Vascular Access Grafts for Chemotherapy Use in Forty Patients at M. D. Anderson Hospital JOHN H. RAAF, M.D., D.PHIL.
Forty-two arteriovenous grafts were placed to provide vascular access in 40 patients with poor or scierosed superficial veins. Thirty-nine patients had malignant disease and required chemotherapy, while one patient with aplastic anemia needed frequent transfusions. Thirty-two grafts were placed in the arm (27 straight and 5 loop), and ten in the leg (femoralfemoral loop). Thirty-seven shunts consisted of 6 mm polytetrafluoroethylene (PTFE), and five were 6 mm Dacron®. The straight brachial artery to axillary vein PTFE graft was preferred, while the PTFE femoral loop graft was a satisfactory alternative. The loop arm graft was associated with a high complication rate and is no longer used. Local anesthesia was employed in all cases except for a 3-year-old child. There was no operative mortality and no severe morbidity, despite subsequent myelosuppression by chemotherapeutic agents injected via these grafts. Thirty patients are alive, while ten died of their malignancy. Twenty-six grafts are functional and have been in place an average 4.4 months (range: 1 to 14 mo.). Acceptance by patients and particularly by personnel in the out-patient chemotherapy unit has been enthusiastic. Vascular access grafts can be inserted safely and provide a convenient route for drawing blood samples, and for administering chemotherapy and intermittent intravenous therapy in selected patients with neoplastic disease. ACCESS in patients receiving chemo5IVASCULAR I therapy is a serious and challenging problem.
Chemotherapy protocols now involve the intense and frequent administration of combinations of drugs, often together with surgery or radiotherapy as part of a multidisciplinary approach. Most chemotherapeutic agents must be administered intravenously, and many are severely irritating and sclerosing when in contact with veins used for infusion. Patients receiving antitumor drugs over months or years are subjected to multiple venipunctures, with gradual thrombosis, sclerosis, and destruction of all available surface
From the Department of Surgery, Section of General Surgery, The University of Texas System Cancer Center, M. D. Anderson Hospital and Tumor Institute, Houston, Texas
vessels. The search for a suitable vein can then become a painful ordeal for the patient and a frustrating experience for the nurse or physician. More seriously, the lack of adequate peripheral veins may lead to infiltration of drugs into extremity soft tissue with subsequent necrosis and ulceration, particularly in the case of Adriamycin.3 Finally, this problem may even prevent the administration of drugs which are
maintaining the patient in remission, resulting in relapse. The problem of vascular access for hemodialysis in the patient with renal failure has been overcome by creation of an arteriovenous fistula, or insertion of an arteriovenous graft. Vascular access grafts now in use consist of double velour Dacron®6, polytetrafluoroethylene (PTFE) expanded Teflon®2, saphenous vein,9'16 or bovine carotid artery.5'12 They most often are placed in the forearm between the radial artery and an antecubital vein, usually the median basilic or
cephalic. We believe cancer patients with poor superficial veins who need chemotherapy can also benefit from a vascular access graft. It should be placed in as central a location as possible to achieve high flow and therefore rapid dilution of the drugs infused. Brisk flow also decreases the risk of graft thrombosis, which is high in patients with neoplasms who may be hypercoagulable secondary to chronic disseminated intravascular
coagulation. 19 Reprint requests: John H. Raaf, M.D., Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, N.Y. (10021). Submitted for publication: April 9, 1979.
The above rationale has led other investigators to insert bovine carotid heterografts from the axillary artery across the sternum to the contralateral axillary vein.5 However, such a procedure is best accomplished
0003-4932/79/1100/0614 $00.95 C J. B. Lippincott Company
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FIG. 1. Brachial artery to axillary vein straight graft in the left arm.
under general anesthesia, and
our
preference in this
group of patients with variable debilitation has been to use only local anesthetics. We now place grafts in one of two positions: 1) a straight brachial artery to axillary vein graft in the upper arm (Fig. 1), or 2) a loop
femoral artery to femoral vein graft in the thigh (Fig. 2). Initially we also placed loop grafts from the axillary artery to axillary vein (Fig. 3), but we now use only straight grafts in the arm.
Materials and Methods All patients were admitted to the hospital, though some authors indicate they place grafts for hemodialysis in outpatients.12 Our procedures were per-
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FIG. 2. Femoral artery to femoral vein loop graft in the right leg.
formed in the operating room using local anesthesia, with an anesthetist in attendance to monitor vital signs and to administer diazepam or fentanyl intravenously for sedation. The single exception was a 3-year-old child who had a general anesthetic. A prophylactic antibiotic (Ancef) was given perioperatively. A modification of the technique of Burdick, Scott and Cosimi6 was developed for placement of straight brachial artery to axillary vein grafts, and this became our preferred method (Fig. 1). Initially, we used 6 mm Dacron,* but we now employ 6 mm polytetrafluoroethylene (PTFE). * Straight tube Double Velour Graft (Meadox Medicals, Inc., P.O. Box 530, Oakland, N.J. 07436).
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FIG. 3.
Loop graft from the
vein in the left arm.
An IV was started, often as a central line in the contralateral subclavian or internal jugular vein, and the arm in which the graft was to be inserted was positioned on an arm board. This was generally the patient's nondominant arm, though in breast cancer patients it was the side opposite the mastectomy. The presence of palpable nodes in an axilla was considered a contraindication to placement of the graft in that arm due to the increased risk of venous occlusion and arm edema. Also, a history of a long-term central line having been placed on one side suggested that the other arm be used, to avoid possible graft occlusion if the subclavian vein on that side was sclerosed or thrombosed. The upper arm was prepped and draped with the arm free. A transverse incision was made under local anesthesia just below the axillary hair line, and the neurovascular structures beneath the fascia exposed. The largest vein was dissected free from the adjacent
Ann.
Surg. November 1979 *
artery and nerves. The size of this vein is the most critical anatomic factor in the success of the graft, and since there are usually at least two veins in this position which join to form a single axillary vein, a determined effort must be made to find the largest. It is frequently on the medial edge of the neurovascular bundle. The selected vein was calibrated and required to accept a 3 mm vascular dilator. If it did not, or if a small catheter failed to pass easily into the subclavian vein, then the graft was placed in the other arm, or a femoral-femoral loop graft was used. Once the vein had been freed over a length of about 2 cm and branches divided and tied with 5-0 silk, a second transverse incision was made across the medial border of the biceps muscle just above the antecubital crease. Once again, the dissection was carried deep to the fascia, and the brachial artery freed over a length of about 2 cm. Small branches were ligated and divided, but a large one was usually not sacrificed. This branch could be temporarily occluded during the creation of the anastomosis by isolation of the entire anastomosis site with a small Satinsky clamp. A subcutaneous tunnel was then created between the two incisions using a 7½ inch clamp,t with the tunnel arching up over the biceps in as superficial a subcutaneous position as possible. This was particularly important in obese patients since the graft tended to sink into the adipose tissue. Also, a graft which lay beneath the medial edge of the biceps was more difficult to locate later for cannulation. A patient with a long arm sometimes required a 1 cm parallel counterincision near the middle part of the tunnel, but a third incision was usually not needed. This incision was placed lateral to the tunnel so that exposure of the graft due to poor healing would not occur. Straight arm grafts were 20-25 cm in length, so two or three grafts could be obtained from the 50-70 cm segment supplied by the PTFE manufacturers (Impra, Inc., 4209 South 36th Place, Phoenix, Arizona 85040; and W. L. Gore and Associates, Inc., 1505 North Fourth Street, Box 1807, Flagstaff, Arizona 86002). Segments to be used were either gas sterilized or flash autoclaved. The patient was systemically heparinized with 5,000 U.S.P. units, and a segment of the vein was isolated with a small Satinsky clamp. The venous anastomosis was performed end-of-graft to side-of-vein using running 6-0 Prolene, with anchoring mattress stitches at the heel and toe of the obliquely cut graft. Magnification with 2.5 power operating loops allowed more accurate placement of these sutures. With the anastomosis complete, the graft was flushed with heparinized saline (10 units/cc) and drawn down through the tunnel, t #32-2075 Varco thoracic forceps, shallow curve. J. Sklar Mfg. Co., Inc., Long Island City, N.Y. 11101.
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FIG. 4. View of the medial aspect of the left upper arm, one month after insertion of a straight PTFE graft. This is a cosmetically acceptable result which leaves the patient's activity unrestricted. The inner arm is a relatively protected site for the graft.
Finally, an endto-side graft to brachial artery anastomosis was performed; the heel mattress suture was placed flrst and run down to the toe on each side, since exposure here was better by this open method. The wounds were irrigated with a neomycin solution and closed with interrupted 3-0 Dexon to the subcutaneous tissue and running subcuticular 4-0 Dexon to the skin. Benzoin and Steri-stripsg were applied and the incisions covered by a very loose noncircumferential gauze and paper tape dressing. The procedure usually took 1½ to 2 hours. Heparin, 1000 units/hr, was given intravenously to a few patients during the first 24 hours postoperatively to maintain graft patency, but we abandoned this procedure since it appeared unnecessary and increased the chance of wound hemorrhage. Initially, we felt that a loop axillary artery to axillary vein graft (Fig. 3) would be desirable, to achieve a high flow. However, the straight grafts (Fig. 1) proved to be more satisfactory since they required much less material to be placed in the upper arm, which decreased tissue reaction and time required for healing before the graft could be used. In patients in whom neither arm was a suitable site for graft placement, a femoral artery to femoral vein loop graft approximately 40 cm in length (Fig. 2) was employed. A transverse incision was made 1 cm below and parallel to the groin crease. End-to-side anastomoses joined the graft to the common femoral vein and artery. The saphenous vein was usually ligated to avoid formation of varicosities. Postoperatively, a sign was placed above the patient's bed stating that no blood pressure measure-
care being taken to avoid a kink or twist.
ments were to be taken using the limb containing the graft, and the patient was instructed never to permit a tourniquet to be placed over the graft. Free activity was permitted, though when the patient was in bed the engrafted arm was elevated on a soft pillow, without compression of the graft site. Discharge was on the first or second postoperative day for patients receiving arm grafts, or several days later for patients receiving thigh grafts. The latter patients were kept in bed the first two days postoperatively. Edema and ecchymosis associated with graft placement resolved by two to three weeks (Fig. 4), and at that time we started routine use for vascular access. Administration of chemotherapy was permitted one week postoperatively in urgent cases, if healing of the graft site appeared satisfactory. The access grafts have proved very useful for drawing blood samples and for administering intermittent (less than eight hours) intravenous fluids or chemotherapy. If the patients are hospitalized, we have encouraged use of the grafts for drawing blood, but not for continuous, long-term intravenous therapy. Since long-term iv therapy through the graft increases the risk of sepsis and injury to the graft, we encouraged the use of centrally-placed subclavian or internal jugular lines in these in-patients. In several patients, however, the grafts were used as iv sites for as long as seven days without complication. To initiate the vascular access graft program, meetings were held with the intravenous nurses who administer chemotherapy to these patients. It was recommended that scalp vein needles no larger than a #20 (usually a #23) be used for cannulation, and
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TABLE 1. Diagnoses of Patients Receiving Vascular Access Grafts
Type of Cancer
Number
Breast carcinoma Hodgkin's lymphoma Lung carcinoma Poorly differentiated lymphoma Bladder carcinoma Soft tissue sarcoma Histiocytic lymphoma Prostate carcinoma Osteosarcoma Colon carcinoma Carcinoid Leukemia Melanoma Aplastic anemia
17 5 4 2 2 2 1 1 I 1 I I 1 1
it was emphasized that firm pressure is needed to slip the needle through the wall of the PTFE graft. The intravenous bottle used for administration of chemotherapy is placed high on an IV pole, since gravity flow alone would then allow infusion into the graft. An infusion pump has been used in only rare instances. Nurses were instructed to puncture the graft at different places along its course rather than in a single site, to avoid weakening the graft at that point. Bleeding should be stopped with mild pressure on the puncture site for three to four minutes after withdrawal of the needle, but not firm pressure, so the graft will not thrombose. Nurses were particularly instructed to confirm graft patency before attempting cannulation, We have found that by far the easiest and most reliable method of determining graft patency is to listen for a bruit in the graft. In our experience, absence of a bruit has always meant the graft was thrombosed. Absence of a palpable thrill or pulse in the graft is less reliable, since these signs may be masked by subcutaneous tissue or edema. Use of Doppler techniques can be misleading, since flow through an underlying artery can be misinterpreted as flow through the graft. These guidelines, as well as a description of the graft, were written up as an instruction booklet and given to the patient for his local physician. Follow-up visits were scheduled initially every week, then every one or two months. TABLE 2. Types of Grafts Inserted (42 Grafts in 40 Patients)
Number Position Arm, straight Leg, loop Arm, loop Material 6 mm PTFE (IMPRA-graft) 6 mm PTFE (GORE-TEX) 6 mm Dacron
27 10 5 28 9 5
Ann.
Surg. * November 1979
Results
Between August, 1977, and March, 1979, 42 vascular grafts were placed in 40 patients with various types of neoplasms (Table 1). All patients were receiving chemotherapy for malignancies, except one patient with idiopathic aplastic anemia who required frequent transfusions. Thirty-three patients were female and seven were male, the predominance of females being in part due to referral of patients with metastatic breast carcinoma. The age range was 3-70 years. Twenty-seven straight arm, five loop arm, and ten loop leg grafts were performed (Table 2). Dacron was used for 5 of the grafts, whereas PTFE was used in 37 (Impra-graftg in 28, Gore-texg graft in 9). No difference in results was noted between the Impra and Gore products. The more frequent use of the Impragraft was based on its lower cost. There was no operative mortality and no severe morbidity. Thirty patients are alive (Table 3), twenty-six of whom have functional grafts which have been in place 1-14 months (mean: 4.4 months). Ten patients died of their malignancy, eight of whom had functional grafts at death which had been in place 1 to 12 months (mean: 3.3 months). There were 18 complications in 15 patients (Table 4). Seven patients experienced thrombosis of their grafts within 24 hours after placement, but four of these had successful thrombectomy and revision. After reoperation, 500-1000 units/hour heparin was given IV continuously for 24-36 hours, then discontinued. These grafts have remained patent and are now one to six months following thrombectomy. In the three other patients early thrombosis was followed by revision, but rethrombosis occurred. In one patient, a 52-year-old woman (D.W.) with metastatic breast carcinoma, a straight Dacron graft placed in her left arm thrombosed within 24 hours after insertion. Revision and thrombectomy were followed by rethrombosis three days later. A loop graft with high flow (1.36 /min. measured by electromagnetic flowmeter) was subsequently placed in her right thigh but thrombosed after one month. By this point she had extensive metastatic breast carcinoma in the lungs, liver, and vertebrae. Dry gangrene of both feet developed, together with hematogical studies consistent with disseminated intravascular coagulation. A bilateral femoral arteriogram showed patent femoral and popliteal arteries, but distal branches below the midcalves could not be visualized. Autopsy one month later confirmed thrombosis of many visceral and peripheral vessels. A 26-year-old woman (M.C.) with Hodgkin's lymphoma rethrombosed her left arm graft after revision, because the single vein available in this arm access
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for the graft-to-vein anastomosis was too small. The graft was removed and a right leg loop graft was placed and is now functioning ten months later. At present, if we find no veins in the upper arm which will accept a 3 mm vascular dilator, we close the incision and use the other arm or a leg. The third patient, a 58-year-old diabetic male (D.R.) in remission from leukemia, thrombosed his straight PTFE right arm graft twice. He had previously had a long silastic central line in his right arm for several weeks, and it was subsequently discovered that his right subclavian vein was thrombosed. Therefore, we now determine whether a previous long-term central line has been used, and confirm patency of the subclavian vein by passing a small catheter into it at the time of surgery. A 51-year-old woman (O.B.) with metastatic colon carcinoma experienced tingling and pain in all fingers of her right hand immediately following insertion of a right upper arm graft. Her right hand was cooler than the left, though motor strength and color were equal. The right radial pulse, which was weak but palpable, could be strengthened by compression of her vascular graft. Her symptoms improved only slightly over the next four weeks. She was returned to the operating room with a diagnosis of a steal syndrome. A small incision was made parallel to the graft under local anesthesia, and a 1-0 silk tie used to band the graft, narrowing it to approximately half its initial diameter. This produced a strong radial pulse, with continued flow through the graft, and disappearance of her symptoms took place over the next few weeks. Four months later she presented to the hospital with cachexia and dehydration, and her graft was found to be thrombosed. Her chemotherapy had been discontinued due to progressive enlargement of her pulmonary metastases, so thrombectomy was not performed. Separation of the skin in a groin incision in two patients healed secondarily without harm to the grafts. Erythema over the graft occurred in three patients, but this resolved in all cases with saline soaks, elevation of the limb, and iv antibiotics. Two grafts were removed for infection. One patient was a 47-year-old woman (F.V.) who had a large open ulceration on the right chest wall due to breast carcinoma. This became infected and the Dacron loop graft placed three months previously in the left arm also became infected. The graft was removed and the graft site healed. A second patient, a 27-year-old man (D.L.) with Hodgkin's lymphoma, had a functioning right arm PTFE loop graft, but he became febrile and severely lymphopenic after receiving chemotherapy at another hospital, and was considered to have possible sepsis secondary to his graft. Therefore, it was removed at that hospital.
TABLE 3. Outcome of Vascular Access Grafts No. grafts Patients alive (30) grafts now in place and functional for: 12-15 months 6-12 months 3-6 months 1-3 months early thrombosis, unsuccessful
7 Average time: 4.4 months 8 10J 2
revision
late thrombosis (both at 4 mos.) graft removed elsewhere for suspected infection (4 mos.)
2
31
Total Patients deceased (10) grafts in place and functional at death early thrombosis, unsuccessful
8
Average time: 3.3 months
revision
late thrombosis (1 mo.) graft removed for late infection (3 mos.) Total
11
Only one patient developed a large ecchymosis over her graft after a blood sample was drawn from it, but this did not prevent further use of the graft. Other described complications of vascular access shunts were not seen in this series. Graft aneurysm or laceration, hematoma, or extravasation of drugs have not occurred. Nor was cardiac failure observed in our series, though many of the patients had received the cardiotoxic drug Adriamycin. Unfortunately, the use of PTFE does not permit the direct measurement of flow through the grafts by electromagnetic flow probes. Discussion In the past, to overcome the problem of difficult vascular access in patients requiring chemotherapy, TABLE 4. Complications After Graft Insertion
Straight
ArmLoop
LegLoop
2
1
1 2
Arm-
Graft function maintained early thrombosis, successful revision skin separation, healed secondarily erythema over graft, cleared with antibiotics steal syndrome, corrected by banding Graft function lost early thrombosis, unsuccessful revision late thrombosis late infection, graft removed suspected late infection, graft removed elsewhere
2
1
1 2 2
1
1
1
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infusion therapy personnel have become skilled in cannulating tiny peripheral vessels. Small bore stainless steel "scalp vein" needles are most often used, because of the ease with which they are inserted and the low incidence of associated infection and inflammation, as emphasized by Center for Disease Control guidelines.1" While scalp vein needles are satisfactory for an infusion over a few hours, their tendency to infiltrate seriously limits their usefulness for administration of, for example, a five day course of chemotherapy. Although short plastic catheters are more secure and less likely to infiltrate, they are associated with a high incidence of phlebitis. Therefore, hospitalized patients receiving a course of chemotherapy lasting several days often have polyethylene central catheters placed via an antecubital, subclavian, or internal jugular vein. Thus the problems of infiltration and drug extravasation are avoided, but they are replaced by the complications of indwelling polyethylene central lines and of repeated insertion of these lines (pneumothorax, brachial plexus or thoracic duct injury, laceration of a major artery, subclavian vein thrombosis, phlebitis, catheter sepsis or leak, and air embolism.17 A more recent approach at M.D. Anderson Hospital has been the use in both in-patients and out-patients of long-term silicone elastomer central venous lines.2'15 Intrasil* (16 Ga., 20" long) or Centrasil* (16 Ga., 8½2" long) catheters introduced through the antecubital or subclavian veins, respectively, now provide access for blood sampling and chemotherapy infusion. Average indwelling time is 30 days, though some of these lines have been used as long as ten months. Over 60 silastic catheters are inserted at our institution per month. Although the patients are frequently immunosuppressed, strict aseptic care with dressing changes three times per week by the patients, their families, or nurses from the Infusion Therapy Team results in a very low rate of infection. A persistent problem has been the frequent occlusion of these lines by clotted blood. A new method for clearing the catheters by instilling 0.4-0.6 ml of a dilute solution of urokinaset (5,000 I.U./cc) or streptokinaset (50,000 I.U./cc) decreased the loss of lines due to clotting from 25% to less than 1%, though declotting by a fibrinolytic agent may be required up to three times per month for each patient.13 Careful flushing after blood has been drawn through the line, and daily instillation of one ml. normal saline containing 100 U.S.P. units of heparin, prevent even more frequent occlusion. * VICRA, Division of Travenol Laboratories, Inc., Dallas, Texas 75220. t Abbokinase (Abbott Laboratories, North Chicago, III. 60064). t Streptase (Hoechst-Roussel Pharmaceuticals, Inc., Behringwerke AG).
Ann. Surg. * November 1979
These light-weight, flexible catheters are removed only infrequently because of phlebitis, fever without a known source ("catheter related sepsis"), central vein thrombosis, or catheter leak. Many cancer patients are not ideal candidates for percutaneous central lines. Some will need chemotherapy for periods longer than a year (often two years), while others cannot or prefer not to undertake the meticulous care required to maintain a percutaneous catheter, or to restrict activities such- as swimming. Individuals who are obese, who have had a mastectomy, or who have had previous complications of central line placement such as subclavian vein thrombosis, may present serious difficulties in the placement of a new silastic line. Therefore, based on experience with hemodialysis patients, permanent arteriovenous fistulae and grafts should be considered as alternative solutions to the problem of angioaccess for chemotherapy. The uremic patient on hemodialysis who has a vascular access problem usually receives a BresciaCimino radial artery-cephalic vein fistula,4 which will dilate the surface veins of his forearm. Patency of such small fistulae is assisted by the hypocoagulability asso-. ciated with azotemia, thought to be secondary to platelet dysfunction. Patients with neoplasia, however, may develop a chronic form of disseminated intravascular coagulation (DIC) manifested by thrombophlebitis, hemorrhage, or arterial thrombosis.19 Cancer patients with even subclinical DIC would be unlikely to keep a small fistula open. In 1974, Steckler, Martin, and colleagues20 created a Brescia-Cimino fistula in 22 patients with leukemia at M. D. Anderson Hospital. They found that those patients who had previously received chemotherapy rarely dilated their already sclerosed veins, but fistulae created before treatment usually were successful. Using this technique, there is considerable variability in the degree of venous dilation and length of time (up to six weeks) needed for dilation to occur. Since the majority of cancer patients with vascular access problems have already received some chemotherapy, it appeared that in most instances a vascular access graft would be more satisfactory than a fistula. Our recent experience with placement of vascular access grafts in 40 patients with neoplasia has been encouraging. We found that the straight brachial artery to axillary vein graft can be safely inserted, heals with minimal discomfort in most patients in two to three weeks, and rarely causes difficulty once healed. Persistent edema of the arm has not occurred, even though the venous anastomosis is performed end-to-side. The loop axillary artery to axillary vein graft, however, was associated with a high complication rate (four complications in three of the five grafts inserted), so is no
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longer used. Other investigators, using looped bovine heterografts in the forearm and upper arm, have been discouraged by their frequent thrombosis.8'12 Haimov and Jacobson suggest that this configuration is "hemodynamically wrong.'"12 The femoral artery to femoral vein loop graft is an alternative when neither arm is a suitable graft site. The large vessels make it technically easy to perform and ensure success as a high-flow, low resistance system. Yet it is a second choice compared to the straight arm graft since 1) postoperative edema persists longer in the thigh than the arm, 2) the wound appears to heal more slowly and skin separation can occur, 3) the patient is usually hospitalized and incapacitated longer, and 4) he must undress each time the graft is used. Nonetheless, two of our femoral loop shunts have been used longer than a year. Once healed, these grafts are quite satisfactory. The thigh is a useful site for vascular access procedures in infants and children, since their arm vessels are so small. Levey and colleagues,16 operating on 74 patients at Boston Children's Hospital, found the access operation of choice in children to be a saphenous vein loop, with the saphenous vein dissected free in the thigh, swung laterally through a subcutaneous tunnel, and the distal end anastomosed end-to-side to the superficial femoral artery. Our own limited experience in the pediatric age group has been with a 3-year-old girl (weighing 12 kg), whose fibrosarcoma of the gingiva was regressing with intensive chemotherapy. She received a 6 mm PTFE femoral-femoral loop graft which has functioned well. PTFE was selected for the majority of our grafts because of previous experience with this material in performing bypasses for arterial insufficiency. However, there does not yet appear to be a clear superiority of one material over others in constructing access grafts. We did notice a tendency of the Dacron graft to erode the overlying skin of one debilitated patient, as did Burdick who advocated a relatively deep tunnel for Dacron shunts.6 Many groups use bovine carotid heterografts (as summarized by Butt et al.8), though authors comparing PTFE and bovine grafts usually favor the PTFE material.7'421 Problems associated with the bovine grafts have been: 1) formation of thinwalled aneurysms (usually due to use of 14 gauge needles for hemodialysis), 2) "blow-out" with severe hemorrhage secondary to infection (a complication not seen with PTFE grafts, which are stable and usually need not be removed despite localized infection), 3) gradual formation of a pseudointima at the venous anastomosis, and 4) difficulty in removal due to tenacious adherence to surrounding tissue. Time is needed to determine the frequency of similar or other difficulties with PTFE, and whether its patency rate
621
is superior to that of bovine heterograft as some have claimed.7'14'21 Insertion of vascular access grafts requires the meticulous techique demanded in all vascular surgery, particularly in the arm where vascular structures lie in close association with the median and ulnar nerves. Ultimate success, as always, depends on persistence and aggressiveness in dealing with complications. Our most frequent complication was graft thrombosis, often occurring within 24 hours after insertion. Early thrombosis was usually due to outflow resistance secondary to an inadequate sized vein. We now avoid this problem by rejecting any vein which will not accept a 3 mm vascular dilator. Thrombosis in the early postoperative period may also be related to poor inflow, due to an unusually small or diseased brachial artery, or to arterial spasm; the radial pulse in the engrafted arm is often weak during the early postoperative period, but will strengthen over the next few days. The dorsalis pedis pulse, however, is always strong immediately after a femoral-femoral graft, likely due to the larger femoral vessels. The few late thromboses we have seen in our cancer patients appear to have been related to low blood volume secondary to dehydration, or to chronic intravascular coagulopathy with a low platelet count and elevated fibrin split products. There have been no cardiac complications in this group of patients, many of whom received the cardiotoxic drug Adriamycin. In none of our patients has any change in heart rate or blood pressure been observed when the graft was first opened. Nor was a positive Branham sign (decrease in heart rate with temporary occlusion of the shunt) observed. Remarkably, longterm use of arteriovenous fistulae and shunts for hemodialysis seldom produces congestive failure.8 Friedberg10 estimates that circulatory disturbances occur when 20-50%o of the cardiac output is shunted through an arteriovenous fistula. In fact, though quite variable, the average increase in cardiac output in asymptomatic patients after opening a fistula or graft created for vascular access is approximately 10-200o.58 A flow greater than 1,000 ml/min through a fistula or graft may8 (but usually does not6) result in congestive failure. Anderson reviewed this rare complication of high output failure and found that the mean fistula flow rate in a group of these patients was 1.5 liters/min.1 All these patients had had previous episodes of congestive heart failure, prolonged hypertension, or coronary insufficiency. Sabistont8 found that even a large (10 mm) fistula created between the aorta and vena cava of a healthy mongrel dog, which increased the cardiac output from 2,540 to 5,640 cc/min, was initially well tolerated. In these animals, heart failure usually appeared by the end of the first month following
Ann. Surg. * November 1979
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operation. In summary, it would appear that an arteriovenous fistula or graft less than 8 mm in diameter (e.g. a 6 mm PTFE shunt) in a patient without a history of heart disease is very unlikely to produce congestive failure. We have found few contraindications to insertion of a vascular access graft. The operation should be timed so as to interfere as little as possible with the patient's chemotherapy protocol, and one should obviously avoid periods of maximum immunosuppression. A low hematocrit (
Forty-two arteriovenous grafts were placed to provide vascular access in 40 patients with poor or scierosed superficial veins. Thirty-nine patients had malignant disease and required chemotherapy, while one patient with aplastic anemia needed frequent transfusions. Thirty-two grafts were placed in the arm (27 straight and 5 loop), and ten in the leg (femoralfemoral loop). Thirty-seven shunts consisted of 6 mm polytetrafluoroethylene (PTFE), and five were 6 mm Dacron®. The straight brachial artery to axillary vein PTFE graft was preferred, while the PTFE femoral loop graft was a satisfactory alternative. The loop arm graft was associated with a high complication rate and is no longer used. Local anesthesia was employed in all cases except for a 3-year-old child. There was no operative mortality and no severe morbidity, despite subsequent myelosuppression by chemotherapeutic agents injected via these grafts. Thirty patients are alive, while ten died of their malignancy. Twenty-six grafts are functional and have been in place an average 4.4 months (range: 1 to 14 mo.). Acceptance by patients and particularly by personnel in the out-patient chemotherapy unit has been enthusiastic. Vascular access grafts can be inserted safely and provide a convenient route for drawing blood samples, and for administering chemotherapy and intermittent intravenous therapy in selected patients with neoplastic disease. ACCESS in patients receiving chemo5IVASCULAR I therapy is a serious and challenging problem.
Chemotherapy protocols now involve the intense and frequent administration of combinations of drugs, often together with surgery or radiotherapy as part of a multidisciplinary approach. Most chemotherapeutic agents must be administered intravenously, and many are severely irritating and sclerosing when in contact with veins used for infusion. Patients receiving antitumor drugs over months or years are subjected to multiple venipunctures, with gradual thrombosis, sclerosis, and destruction of all available surface
From the Department of Surgery, Section of General Surgery, The University of Texas System Cancer Center, M. D. Anderson Hospital and Tumor Institute, Houston, Texas
vessels. The search for a suitable vein can then become a painful ordeal for the patient and a frustrating experience for the nurse or physician. More seriously, the lack of adequate peripheral veins may lead to infiltration of drugs into extremity soft tissue with subsequent necrosis and ulceration, particularly in the case of Adriamycin.3 Finally, this problem may even prevent the administration of drugs which are
maintaining the patient in remission, resulting in relapse. The problem of vascular access for hemodialysis in the patient with renal failure has been overcome by creation of an arteriovenous fistula, or insertion of an arteriovenous graft. Vascular access grafts now in use consist of double velour Dacron®6, polytetrafluoroethylene (PTFE) expanded Teflon®2, saphenous vein,9'16 or bovine carotid artery.5'12 They most often are placed in the forearm between the radial artery and an antecubital vein, usually the median basilic or
cephalic. We believe cancer patients with poor superficial veins who need chemotherapy can also benefit from a vascular access graft. It should be placed in as central a location as possible to achieve high flow and therefore rapid dilution of the drugs infused. Brisk flow also decreases the risk of graft thrombosis, which is high in patients with neoplasms who may be hypercoagulable secondary to chronic disseminated intravascular
coagulation. 19 Reprint requests: John H. Raaf, M.D., Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, N.Y. (10021). Submitted for publication: April 9, 1979.
The above rationale has led other investigators to insert bovine carotid heterografts from the axillary artery across the sternum to the contralateral axillary vein.5 However, such a procedure is best accomplished
0003-4932/79/1100/0614 $00.95 C J. B. Lippincott Company
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FIG. 1. Brachial artery to axillary vein straight graft in the left arm.
under general anesthesia, and
our
preference in this
group of patients with variable debilitation has been to use only local anesthetics. We now place grafts in one of two positions: 1) a straight brachial artery to axillary vein graft in the upper arm (Fig. 1), or 2) a loop
femoral artery to femoral vein graft in the thigh (Fig. 2). Initially we also placed loop grafts from the axillary artery to axillary vein (Fig. 3), but we now use only straight grafts in the arm.
Materials and Methods All patients were admitted to the hospital, though some authors indicate they place grafts for hemodialysis in outpatients.12 Our procedures were per-
615
FIG. 2. Femoral artery to femoral vein loop graft in the right leg.
formed in the operating room using local anesthesia, with an anesthetist in attendance to monitor vital signs and to administer diazepam or fentanyl intravenously for sedation. The single exception was a 3-year-old child who had a general anesthetic. A prophylactic antibiotic (Ancef) was given perioperatively. A modification of the technique of Burdick, Scott and Cosimi6 was developed for placement of straight brachial artery to axillary vein grafts, and this became our preferred method (Fig. 1). Initially, we used 6 mm Dacron,* but we now employ 6 mm polytetrafluoroethylene (PTFE). * Straight tube Double Velour Graft (Meadox Medicals, Inc., P.O. Box 530, Oakland, N.J. 07436).
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FIG. 3.
Loop graft from the
vein in the left arm.
An IV was started, often as a central line in the contralateral subclavian or internal jugular vein, and the arm in which the graft was to be inserted was positioned on an arm board. This was generally the patient's nondominant arm, though in breast cancer patients it was the side opposite the mastectomy. The presence of palpable nodes in an axilla was considered a contraindication to placement of the graft in that arm due to the increased risk of venous occlusion and arm edema. Also, a history of a long-term central line having been placed on one side suggested that the other arm be used, to avoid possible graft occlusion if the subclavian vein on that side was sclerosed or thrombosed. The upper arm was prepped and draped with the arm free. A transverse incision was made under local anesthesia just below the axillary hair line, and the neurovascular structures beneath the fascia exposed. The largest vein was dissected free from the adjacent
Ann.
Surg. November 1979 *
artery and nerves. The size of this vein is the most critical anatomic factor in the success of the graft, and since there are usually at least two veins in this position which join to form a single axillary vein, a determined effort must be made to find the largest. It is frequently on the medial edge of the neurovascular bundle. The selected vein was calibrated and required to accept a 3 mm vascular dilator. If it did not, or if a small catheter failed to pass easily into the subclavian vein, then the graft was placed in the other arm, or a femoral-femoral loop graft was used. Once the vein had been freed over a length of about 2 cm and branches divided and tied with 5-0 silk, a second transverse incision was made across the medial border of the biceps muscle just above the antecubital crease. Once again, the dissection was carried deep to the fascia, and the brachial artery freed over a length of about 2 cm. Small branches were ligated and divided, but a large one was usually not sacrificed. This branch could be temporarily occluded during the creation of the anastomosis by isolation of the entire anastomosis site with a small Satinsky clamp. A subcutaneous tunnel was then created between the two incisions using a 7½ inch clamp,t with the tunnel arching up over the biceps in as superficial a subcutaneous position as possible. This was particularly important in obese patients since the graft tended to sink into the adipose tissue. Also, a graft which lay beneath the medial edge of the biceps was more difficult to locate later for cannulation. A patient with a long arm sometimes required a 1 cm parallel counterincision near the middle part of the tunnel, but a third incision was usually not needed. This incision was placed lateral to the tunnel so that exposure of the graft due to poor healing would not occur. Straight arm grafts were 20-25 cm in length, so two or three grafts could be obtained from the 50-70 cm segment supplied by the PTFE manufacturers (Impra, Inc., 4209 South 36th Place, Phoenix, Arizona 85040; and W. L. Gore and Associates, Inc., 1505 North Fourth Street, Box 1807, Flagstaff, Arizona 86002). Segments to be used were either gas sterilized or flash autoclaved. The patient was systemically heparinized with 5,000 U.S.P. units, and a segment of the vein was isolated with a small Satinsky clamp. The venous anastomosis was performed end-of-graft to side-of-vein using running 6-0 Prolene, with anchoring mattress stitches at the heel and toe of the obliquely cut graft. Magnification with 2.5 power operating loops allowed more accurate placement of these sutures. With the anastomosis complete, the graft was flushed with heparinized saline (10 units/cc) and drawn down through the tunnel, t #32-2075 Varco thoracic forceps, shallow curve. J. Sklar Mfg. Co., Inc., Long Island City, N.Y. 11101.
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FIG. 4. View of the medial aspect of the left upper arm, one month after insertion of a straight PTFE graft. This is a cosmetically acceptable result which leaves the patient's activity unrestricted. The inner arm is a relatively protected site for the graft.
Finally, an endto-side graft to brachial artery anastomosis was performed; the heel mattress suture was placed flrst and run down to the toe on each side, since exposure here was better by this open method. The wounds were irrigated with a neomycin solution and closed with interrupted 3-0 Dexon to the subcutaneous tissue and running subcuticular 4-0 Dexon to the skin. Benzoin and Steri-stripsg were applied and the incisions covered by a very loose noncircumferential gauze and paper tape dressing. The procedure usually took 1½ to 2 hours. Heparin, 1000 units/hr, was given intravenously to a few patients during the first 24 hours postoperatively to maintain graft patency, but we abandoned this procedure since it appeared unnecessary and increased the chance of wound hemorrhage. Initially, we felt that a loop axillary artery to axillary vein graft (Fig. 3) would be desirable, to achieve a high flow. However, the straight grafts (Fig. 1) proved to be more satisfactory since they required much less material to be placed in the upper arm, which decreased tissue reaction and time required for healing before the graft could be used. In patients in whom neither arm was a suitable site for graft placement, a femoral artery to femoral vein loop graft approximately 40 cm in length (Fig. 2) was employed. A transverse incision was made 1 cm below and parallel to the groin crease. End-to-side anastomoses joined the graft to the common femoral vein and artery. The saphenous vein was usually ligated to avoid formation of varicosities. Postoperatively, a sign was placed above the patient's bed stating that no blood pressure measure-
care being taken to avoid a kink or twist.
ments were to be taken using the limb containing the graft, and the patient was instructed never to permit a tourniquet to be placed over the graft. Free activity was permitted, though when the patient was in bed the engrafted arm was elevated on a soft pillow, without compression of the graft site. Discharge was on the first or second postoperative day for patients receiving arm grafts, or several days later for patients receiving thigh grafts. The latter patients were kept in bed the first two days postoperatively. Edema and ecchymosis associated with graft placement resolved by two to three weeks (Fig. 4), and at that time we started routine use for vascular access. Administration of chemotherapy was permitted one week postoperatively in urgent cases, if healing of the graft site appeared satisfactory. The access grafts have proved very useful for drawing blood samples and for administering intermittent (less than eight hours) intravenous fluids or chemotherapy. If the patients are hospitalized, we have encouraged use of the grafts for drawing blood, but not for continuous, long-term intravenous therapy. Since long-term iv therapy through the graft increases the risk of sepsis and injury to the graft, we encouraged the use of centrally-placed subclavian or internal jugular lines in these in-patients. In several patients, however, the grafts were used as iv sites for as long as seven days without complication. To initiate the vascular access graft program, meetings were held with the intravenous nurses who administer chemotherapy to these patients. It was recommended that scalp vein needles no larger than a #20 (usually a #23) be used for cannulation, and
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TABLE 1. Diagnoses of Patients Receiving Vascular Access Grafts
Type of Cancer
Number
Breast carcinoma Hodgkin's lymphoma Lung carcinoma Poorly differentiated lymphoma Bladder carcinoma Soft tissue sarcoma Histiocytic lymphoma Prostate carcinoma Osteosarcoma Colon carcinoma Carcinoid Leukemia Melanoma Aplastic anemia
17 5 4 2 2 2 1 1 I 1 I I 1 1
it was emphasized that firm pressure is needed to slip the needle through the wall of the PTFE graft. The intravenous bottle used for administration of chemotherapy is placed high on an IV pole, since gravity flow alone would then allow infusion into the graft. An infusion pump has been used in only rare instances. Nurses were instructed to puncture the graft at different places along its course rather than in a single site, to avoid weakening the graft at that point. Bleeding should be stopped with mild pressure on the puncture site for three to four minutes after withdrawal of the needle, but not firm pressure, so the graft will not thrombose. Nurses were particularly instructed to confirm graft patency before attempting cannulation, We have found that by far the easiest and most reliable method of determining graft patency is to listen for a bruit in the graft. In our experience, absence of a bruit has always meant the graft was thrombosed. Absence of a palpable thrill or pulse in the graft is less reliable, since these signs may be masked by subcutaneous tissue or edema. Use of Doppler techniques can be misleading, since flow through an underlying artery can be misinterpreted as flow through the graft. These guidelines, as well as a description of the graft, were written up as an instruction booklet and given to the patient for his local physician. Follow-up visits were scheduled initially every week, then every one or two months. TABLE 2. Types of Grafts Inserted (42 Grafts in 40 Patients)
Number Position Arm, straight Leg, loop Arm, loop Material 6 mm PTFE (IMPRA-graft) 6 mm PTFE (GORE-TEX) 6 mm Dacron
27 10 5 28 9 5
Ann.
Surg. * November 1979
Results
Between August, 1977, and March, 1979, 42 vascular grafts were placed in 40 patients with various types of neoplasms (Table 1). All patients were receiving chemotherapy for malignancies, except one patient with idiopathic aplastic anemia who required frequent transfusions. Thirty-three patients were female and seven were male, the predominance of females being in part due to referral of patients with metastatic breast carcinoma. The age range was 3-70 years. Twenty-seven straight arm, five loop arm, and ten loop leg grafts were performed (Table 2). Dacron was used for 5 of the grafts, whereas PTFE was used in 37 (Impra-graftg in 28, Gore-texg graft in 9). No difference in results was noted between the Impra and Gore products. The more frequent use of the Impragraft was based on its lower cost. There was no operative mortality and no severe morbidity. Thirty patients are alive (Table 3), twenty-six of whom have functional grafts which have been in place 1-14 months (mean: 4.4 months). Ten patients died of their malignancy, eight of whom had functional grafts at death which had been in place 1 to 12 months (mean: 3.3 months). There were 18 complications in 15 patients (Table 4). Seven patients experienced thrombosis of their grafts within 24 hours after placement, but four of these had successful thrombectomy and revision. After reoperation, 500-1000 units/hour heparin was given IV continuously for 24-36 hours, then discontinued. These grafts have remained patent and are now one to six months following thrombectomy. In the three other patients early thrombosis was followed by revision, but rethrombosis occurred. In one patient, a 52-year-old woman (D.W.) with metastatic breast carcinoma, a straight Dacron graft placed in her left arm thrombosed within 24 hours after insertion. Revision and thrombectomy were followed by rethrombosis three days later. A loop graft with high flow (1.36 /min. measured by electromagnetic flowmeter) was subsequently placed in her right thigh but thrombosed after one month. By this point she had extensive metastatic breast carcinoma in the lungs, liver, and vertebrae. Dry gangrene of both feet developed, together with hematogical studies consistent with disseminated intravascular coagulation. A bilateral femoral arteriogram showed patent femoral and popliteal arteries, but distal branches below the midcalves could not be visualized. Autopsy one month later confirmed thrombosis of many visceral and peripheral vessels. A 26-year-old woman (M.C.) with Hodgkin's lymphoma rethrombosed her left arm graft after revision, because the single vein available in this arm access
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for the graft-to-vein anastomosis was too small. The graft was removed and a right leg loop graft was placed and is now functioning ten months later. At present, if we find no veins in the upper arm which will accept a 3 mm vascular dilator, we close the incision and use the other arm or a leg. The third patient, a 58-year-old diabetic male (D.R.) in remission from leukemia, thrombosed his straight PTFE right arm graft twice. He had previously had a long silastic central line in his right arm for several weeks, and it was subsequently discovered that his right subclavian vein was thrombosed. Therefore, we now determine whether a previous long-term central line has been used, and confirm patency of the subclavian vein by passing a small catheter into it at the time of surgery. A 51-year-old woman (O.B.) with metastatic colon carcinoma experienced tingling and pain in all fingers of her right hand immediately following insertion of a right upper arm graft. Her right hand was cooler than the left, though motor strength and color were equal. The right radial pulse, which was weak but palpable, could be strengthened by compression of her vascular graft. Her symptoms improved only slightly over the next four weeks. She was returned to the operating room with a diagnosis of a steal syndrome. A small incision was made parallel to the graft under local anesthesia, and a 1-0 silk tie used to band the graft, narrowing it to approximately half its initial diameter. This produced a strong radial pulse, with continued flow through the graft, and disappearance of her symptoms took place over the next few weeks. Four months later she presented to the hospital with cachexia and dehydration, and her graft was found to be thrombosed. Her chemotherapy had been discontinued due to progressive enlargement of her pulmonary metastases, so thrombectomy was not performed. Separation of the skin in a groin incision in two patients healed secondarily without harm to the grafts. Erythema over the graft occurred in three patients, but this resolved in all cases with saline soaks, elevation of the limb, and iv antibiotics. Two grafts were removed for infection. One patient was a 47-year-old woman (F.V.) who had a large open ulceration on the right chest wall due to breast carcinoma. This became infected and the Dacron loop graft placed three months previously in the left arm also became infected. The graft was removed and the graft site healed. A second patient, a 27-year-old man (D.L.) with Hodgkin's lymphoma, had a functioning right arm PTFE loop graft, but he became febrile and severely lymphopenic after receiving chemotherapy at another hospital, and was considered to have possible sepsis secondary to his graft. Therefore, it was removed at that hospital.
TABLE 3. Outcome of Vascular Access Grafts No. grafts Patients alive (30) grafts now in place and functional for: 12-15 months 6-12 months 3-6 months 1-3 months early thrombosis, unsuccessful
7 Average time: 4.4 months 8 10J 2
revision
late thrombosis (both at 4 mos.) graft removed elsewhere for suspected infection (4 mos.)
2
31
Total Patients deceased (10) grafts in place and functional at death early thrombosis, unsuccessful
8
Average time: 3.3 months
revision
late thrombosis (1 mo.) graft removed for late infection (3 mos.) Total
11
Only one patient developed a large ecchymosis over her graft after a blood sample was drawn from it, but this did not prevent further use of the graft. Other described complications of vascular access shunts were not seen in this series. Graft aneurysm or laceration, hematoma, or extravasation of drugs have not occurred. Nor was cardiac failure observed in our series, though many of the patients had received the cardiotoxic drug Adriamycin. Unfortunately, the use of PTFE does not permit the direct measurement of flow through the grafts by electromagnetic flow probes. Discussion In the past, to overcome the problem of difficult vascular access in patients requiring chemotherapy, TABLE 4. Complications After Graft Insertion
Straight
ArmLoop
LegLoop
2
1
1 2
Arm-
Graft function maintained early thrombosis, successful revision skin separation, healed secondarily erythema over graft, cleared with antibiotics steal syndrome, corrected by banding Graft function lost early thrombosis, unsuccessful revision late thrombosis late infection, graft removed suspected late infection, graft removed elsewhere
2
1
1 2 2
1
1
1
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infusion therapy personnel have become skilled in cannulating tiny peripheral vessels. Small bore stainless steel "scalp vein" needles are most often used, because of the ease with which they are inserted and the low incidence of associated infection and inflammation, as emphasized by Center for Disease Control guidelines.1" While scalp vein needles are satisfactory for an infusion over a few hours, their tendency to infiltrate seriously limits their usefulness for administration of, for example, a five day course of chemotherapy. Although short plastic catheters are more secure and less likely to infiltrate, they are associated with a high incidence of phlebitis. Therefore, hospitalized patients receiving a course of chemotherapy lasting several days often have polyethylene central catheters placed via an antecubital, subclavian, or internal jugular vein. Thus the problems of infiltration and drug extravasation are avoided, but they are replaced by the complications of indwelling polyethylene central lines and of repeated insertion of these lines (pneumothorax, brachial plexus or thoracic duct injury, laceration of a major artery, subclavian vein thrombosis, phlebitis, catheter sepsis or leak, and air embolism.17 A more recent approach at M.D. Anderson Hospital has been the use in both in-patients and out-patients of long-term silicone elastomer central venous lines.2'15 Intrasil* (16 Ga., 20" long) or Centrasil* (16 Ga., 8½2" long) catheters introduced through the antecubital or subclavian veins, respectively, now provide access for blood sampling and chemotherapy infusion. Average indwelling time is 30 days, though some of these lines have been used as long as ten months. Over 60 silastic catheters are inserted at our institution per month. Although the patients are frequently immunosuppressed, strict aseptic care with dressing changes three times per week by the patients, their families, or nurses from the Infusion Therapy Team results in a very low rate of infection. A persistent problem has been the frequent occlusion of these lines by clotted blood. A new method for clearing the catheters by instilling 0.4-0.6 ml of a dilute solution of urokinaset (5,000 I.U./cc) or streptokinaset (50,000 I.U./cc) decreased the loss of lines due to clotting from 25% to less than 1%, though declotting by a fibrinolytic agent may be required up to three times per month for each patient.13 Careful flushing after blood has been drawn through the line, and daily instillation of one ml. normal saline containing 100 U.S.P. units of heparin, prevent even more frequent occlusion. * VICRA, Division of Travenol Laboratories, Inc., Dallas, Texas 75220. t Abbokinase (Abbott Laboratories, North Chicago, III. 60064). t Streptase (Hoechst-Roussel Pharmaceuticals, Inc., Behringwerke AG).
Ann. Surg. * November 1979
These light-weight, flexible catheters are removed only infrequently because of phlebitis, fever without a known source ("catheter related sepsis"), central vein thrombosis, or catheter leak. Many cancer patients are not ideal candidates for percutaneous central lines. Some will need chemotherapy for periods longer than a year (often two years), while others cannot or prefer not to undertake the meticulous care required to maintain a percutaneous catheter, or to restrict activities such- as swimming. Individuals who are obese, who have had a mastectomy, or who have had previous complications of central line placement such as subclavian vein thrombosis, may present serious difficulties in the placement of a new silastic line. Therefore, based on experience with hemodialysis patients, permanent arteriovenous fistulae and grafts should be considered as alternative solutions to the problem of angioaccess for chemotherapy. The uremic patient on hemodialysis who has a vascular access problem usually receives a BresciaCimino radial artery-cephalic vein fistula,4 which will dilate the surface veins of his forearm. Patency of such small fistulae is assisted by the hypocoagulability asso-. ciated with azotemia, thought to be secondary to platelet dysfunction. Patients with neoplasia, however, may develop a chronic form of disseminated intravascular coagulation (DIC) manifested by thrombophlebitis, hemorrhage, or arterial thrombosis.19 Cancer patients with even subclinical DIC would be unlikely to keep a small fistula open. In 1974, Steckler, Martin, and colleagues20 created a Brescia-Cimino fistula in 22 patients with leukemia at M. D. Anderson Hospital. They found that those patients who had previously received chemotherapy rarely dilated their already sclerosed veins, but fistulae created before treatment usually were successful. Using this technique, there is considerable variability in the degree of venous dilation and length of time (up to six weeks) needed for dilation to occur. Since the majority of cancer patients with vascular access problems have already received some chemotherapy, it appeared that in most instances a vascular access graft would be more satisfactory than a fistula. Our recent experience with placement of vascular access grafts in 40 patients with neoplasia has been encouraging. We found that the straight brachial artery to axillary vein graft can be safely inserted, heals with minimal discomfort in most patients in two to three weeks, and rarely causes difficulty once healed. Persistent edema of the arm has not occurred, even though the venous anastomosis is performed end-to-side. The loop axillary artery to axillary vein graft, however, was associated with a high complication rate (four complications in three of the five grafts inserted), so is no
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VASCULAR ACCESS GRAFTS
longer used. Other investigators, using looped bovine heterografts in the forearm and upper arm, have been discouraged by their frequent thrombosis.8'12 Haimov and Jacobson suggest that this configuration is "hemodynamically wrong.'"12 The femoral artery to femoral vein loop graft is an alternative when neither arm is a suitable graft site. The large vessels make it technically easy to perform and ensure success as a high-flow, low resistance system. Yet it is a second choice compared to the straight arm graft since 1) postoperative edema persists longer in the thigh than the arm, 2) the wound appears to heal more slowly and skin separation can occur, 3) the patient is usually hospitalized and incapacitated longer, and 4) he must undress each time the graft is used. Nonetheless, two of our femoral loop shunts have been used longer than a year. Once healed, these grafts are quite satisfactory. The thigh is a useful site for vascular access procedures in infants and children, since their arm vessels are so small. Levey and colleagues,16 operating on 74 patients at Boston Children's Hospital, found the access operation of choice in children to be a saphenous vein loop, with the saphenous vein dissected free in the thigh, swung laterally through a subcutaneous tunnel, and the distal end anastomosed end-to-side to the superficial femoral artery. Our own limited experience in the pediatric age group has been with a 3-year-old girl (weighing 12 kg), whose fibrosarcoma of the gingiva was regressing with intensive chemotherapy. She received a 6 mm PTFE femoral-femoral loop graft which has functioned well. PTFE was selected for the majority of our grafts because of previous experience with this material in performing bypasses for arterial insufficiency. However, there does not yet appear to be a clear superiority of one material over others in constructing access grafts. We did notice a tendency of the Dacron graft to erode the overlying skin of one debilitated patient, as did Burdick who advocated a relatively deep tunnel for Dacron shunts.6 Many groups use bovine carotid heterografts (as summarized by Butt et al.8), though authors comparing PTFE and bovine grafts usually favor the PTFE material.7'421 Problems associated with the bovine grafts have been: 1) formation of thinwalled aneurysms (usually due to use of 14 gauge needles for hemodialysis), 2) "blow-out" with severe hemorrhage secondary to infection (a complication not seen with PTFE grafts, which are stable and usually need not be removed despite localized infection), 3) gradual formation of a pseudointima at the venous anastomosis, and 4) difficulty in removal due to tenacious adherence to surrounding tissue. Time is needed to determine the frequency of similar or other difficulties with PTFE, and whether its patency rate
621
is superior to that of bovine heterograft as some have claimed.7'14'21 Insertion of vascular access grafts requires the meticulous techique demanded in all vascular surgery, particularly in the arm where vascular structures lie in close association with the median and ulnar nerves. Ultimate success, as always, depends on persistence and aggressiveness in dealing with complications. Our most frequent complication was graft thrombosis, often occurring within 24 hours after insertion. Early thrombosis was usually due to outflow resistance secondary to an inadequate sized vein. We now avoid this problem by rejecting any vein which will not accept a 3 mm vascular dilator. Thrombosis in the early postoperative period may also be related to poor inflow, due to an unusually small or diseased brachial artery, or to arterial spasm; the radial pulse in the engrafted arm is often weak during the early postoperative period, but will strengthen over the next few days. The dorsalis pedis pulse, however, is always strong immediately after a femoral-femoral graft, likely due to the larger femoral vessels. The few late thromboses we have seen in our cancer patients appear to have been related to low blood volume secondary to dehydration, or to chronic intravascular coagulopathy with a low platelet count and elevated fibrin split products. There have been no cardiac complications in this group of patients, many of whom received the cardiotoxic drug Adriamycin. In none of our patients has any change in heart rate or blood pressure been observed when the graft was first opened. Nor was a positive Branham sign (decrease in heart rate with temporary occlusion of the shunt) observed. Remarkably, longterm use of arteriovenous fistulae and shunts for hemodialysis seldom produces congestive failure.8 Friedberg10 estimates that circulatory disturbances occur when 20-50%o of the cardiac output is shunted through an arteriovenous fistula. In fact, though quite variable, the average increase in cardiac output in asymptomatic patients after opening a fistula or graft created for vascular access is approximately 10-200o.58 A flow greater than 1,000 ml/min through a fistula or graft may8 (but usually does not6) result in congestive failure. Anderson reviewed this rare complication of high output failure and found that the mean fistula flow rate in a group of these patients was 1.5 liters/min.1 All these patients had had previous episodes of congestive heart failure, prolonged hypertension, or coronary insufficiency. Sabistont8 found that even a large (10 mm) fistula created between the aorta and vena cava of a healthy mongrel dog, which increased the cardiac output from 2,540 to 5,640 cc/min, was initially well tolerated. In these animals, heart failure usually appeared by the end of the first month following
Ann. Surg. * November 1979
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operation. In summary, it would appear that an arteriovenous fistula or graft less than 8 mm in diameter (e.g. a 6 mm PTFE shunt) in a patient without a history of heart disease is very unlikely to produce congestive failure. We have found few contraindications to insertion of a vascular access graft. The operation should be timed so as to interfere as little as possible with the patient's chemotherapy protocol, and one should obviously avoid periods of maximum immunosuppression. A low hematocrit (
