Original articles

Technique and Results of Vascular Endoscopy in Arterial and Venous Reconstructions K.D. Woelfle, MD, H. Bruijnen, N. Zuegel, MD, H. Weber, MD, R. Jakob, H. Eoeprecht, MD, Augsburg, Germany

In an effort to maximize results, vascular endoscopy was used in our institution to monitor arterial and venous reconstructions. Since 1982, angioscopy was applied as a control method in 182 venous thrombectomies to treat iliofemoral thrombosis and 114 aortoiliac thromboendarterectomies. Of the cases with venous thrombectomy reviewed, 50% were incomplete by endoscopic evidence; of these, in 80% the remaining clots could be partly or completely removed. Additionally, in six patients a venous spur was found. Of 114 attempted aortoiliac thromboendarterectomies, only 91 could be completed. In the remainder, endoscopic evidence of persistent intimal flaps forced us to bypass the affected segments. With further miniaturization of the angioscopes, the method was also applied to check vessel repair on small-caliber arteries. In an initial study with 220 femorodistal bypasses we were unable to find a statistically significant difference of primary patency in grafts that were endoscopically controlled or not. In the learning phase with the in situ technique, we identified competent valve remnants in 40%, but this rate could be reduced to 12.7% with growing experience in valvulotomy. We conclude from our data that angioscopy is very helpful in assessing the morphological integrity of aortoiliac thromboendarterectomies and venous thrombectomies. The actual value in infrainguinal arterial reconstructions still remains to be proven. (Ann Vasc Surg 1992;6:347-356). KEY WORDS: Aortoiliac thromboendarterectomy; venous thrombectomy; infrainguinal grafts; endoscopy; grafts.

Vascular endoscopy is currently the most exact monitoring method available for checking the precise performance of vascular reconstructions intraoperatively. Initially introduced by Vollmar [l] for inspection of large-caliber arteries and veins, anFrom the Department of Vascular and Thoracic Surgery, Zentralklinikum, Augsburg, Germany. Reprint requests: K.D. Woelfle, MD, Zentralklinikum, Stenglinstr.2, 8900 Augsburg, Germany.

gioscopy started to move into the area of smallcaliber vessels around 10 years ago thanks to increasing miniaturization of the apparatus used. Vascular endoscopy is currently used in our hospital to check the following operations: aortoiliac thromboendarterectomy, iliofemoral venous thrombectomy, and femorocrural reconstructions. This paper describes our technique and the results we have obtained when using endoscopy in the above fields. 347

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TABLE I.mTechnical data on currently used angioscopes* Model

Viewing angle

Outer diameter

Working length

Angle bend

PF 22

75 °

2.2 mm

1200 mm

URF-P

75 °

3.6 m m

700 m m

100 °

6.0 m m

550 m m

BF-1T20

120 ° 120 ° 160 ° 100 ° 180 ° 100 °

up down up down up down

Application Infrainguinal reconstructions (autologous) T E A of the external iliac artery venous thrombectomy, TEA of the c o m m o n lilac artery

TEA = thromboendarterectomy *Olympus Optical Co, Lake Success, New York.

T E C H N I C A L ASPECTS OF VASCULAR ENDOSCOPY Prerequisites

Endoscopes

Only flexible endoscopes with a steerable tip were used in our series. The specifications of the apparatus currently used by us and the respective applications are shown in Table I. The endoscopes were connected to a light source by means of a cable. We used a halogen lamp with a luminous power of 150 W (Olympus CLE-F 10~). This provided a sufficiently bright image both for direct observation and for photographic documentation of the findings.

The conditions necessary to perform angioscopy remain the same as those described by Vollmar [1]: temporary blood flow interruption, blood replacement with a transparent medium, and availability of suitable endoscopes. Since the technical details of vascular endoscopy have been described several times by our working group [2--4], we shall summarize the important aspects only briefly here. Following blood flow interruption, which will be dealt with in detail later on, it is necessary to replace the blood with an optically transparent medium in order to produce clear viewing conditions. We use Ringer's solution, which is supplied in 1000 ml plastic bags, These bags are then pressurized outside the sterile area by means of an inflatable cuff. The bags are connected with the endoscope in the operation area by means of an infusion system. In order to avoid endothelial damage, the pressure shown on the pressure gauge should not exceed 200 mmHg. The irrigation using large-caliber endoscopes is done directly through the working channel of the inserted device. In the case of thin fiberscopes, which do not possess an irrigating channel, the irrigation fluid is introduced either through a double lumen cannula, through which the endoscope is also inserted, or by means of a vein catheter advanced parallel to the angloscope. The advantage of the latter method is more effective irrigation of peripheral bypass sections with heavy blood reflux. While the required irrigation volume for arterial reconstructions is approximately 300-500 ml on average, volumes > 1000 ml must sometimes be expected in the venous area in particular. In the future, we will be able to irrigate using a special roller pump (Olympus Angiopump*), which is controlled by means of a foot pedal, and provides flow rates corresponding to the needs of a particular situation. However, approval for use of this device is still pending in Germany.

The apparatus should be cleaned carefully immediately after use, in accordance with the manufacturer's instructions. This includes checking the sheath for leaks, as well as checking the functioning of the bending mechanism. Excessive kinking of the

*Olympus Corporation, Lake Success, New York.

+ O l y m p uCorporation, s Lake Success, New York.

Angioscopy method

The angioscope is inserted in the vascular section which we wished to inspect after interruption of the blood flow and connection of the irrigation device. Since a constant pressure level of the introduced fluid is necessary to guarantee clear vision, the entry point must be carefully sealed off. This is best done with a tourniquet. The angioscope must be moved in the vessel during examination with the greatest care by slight counterrotation. The examination must be broken off immediately in the event of wall contact, e.g, in narrow crurat vein bypasses. Thanks to the steerable tip, it is possible to overcome bends in the bypass or vessel without problems. At the same time, it is possible to inspect the whole circumference of the vessel. The findings are documented by means of pictures taken with a singlelens reflex camera through the eyepiece. A more elegant solution is provided by connection to a video camera. The examination can then be viewed on a monitor by the whole operating team and can also be recorded. Maintenance of the apparatus

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a

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b

Fig. 1. (a) Blood flow interruption and endoscopy for transfemoral closed and semi-closed TEA through an additional extraperitoneal access. (b) Endoscopy for transperitoneal semi-closed TEA of the common iliac artery.

endoscope must be avoided during all this work in order to prevent fiber breaks in the optical system. A venting cap must be attached before sterilization, otherwise the air in the endoscope will not be able to escape and the sheath will burst. Sterilization is performed with ethylene oxide at a temperature of 55°C for a maximum period of 105 minutes. After this, the apparatus must be aerated in a special aeration chamber for 12 hours.

AORTOILIAC THROMBOENDARTERECTOMIES Vascular e n d o s c o p y was used as a monitoring method in 114 aortoiliac t h r o m b o e n d a r t e r e c t o m y operations in the period from September 1, 1982 to December 31, 1990. These operations consisted of 42 semi-closed transperitoneal thromboendarterectomies of the c o m m o n iliac artery as well as 72

disobliterations of the external iliac artery. The latter operations were performed in 27 patients as a closed retrograde transfemoral procedure and in 45 patients semiclosed via an additional retroperitoneal access. Figure I shows the procedure for blood flow interruption and e n d o s c o p y for the individual operating methods. The quality of angioscopy for this operation was classified as being at least satisfactory for all examinations. In 23 of 114 cases, it was necessary to change to a bypass method due to intimal flaps which could not be removed with the ring (Fig. 2). Consequently, only 91 operations could be completed as thromboendarterectomies (TEA) as planned. Of the unsuccessful TEA attempts, disobliterations of the external iliac artery were involved in 22 cases, whereas the common iliac artery was involved only once. The 30-day occlusion rate was 3.3% in our series after endoscopically monitored TEA.

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vein and twice in the area of the femoral vein. Of 83 disobliterations of pelvic veins which could be assessed, only 42 were classified as complete after endoscopic inspection. Relevant residual clots were identified in 41 cases, and it was then possible to completely (n = 12) or largely (n = 20) remove these by further thrombectomy maneuvers in 32 patients. In nine cases, it was necessary to leave significant residual thrombi (Fig. 4). A venous spur was detected in six patients. Six of 11 thrombectomies of the femoral vein that could be assessed were primarily complete. It was possible to completely or partially remove residual clots in four patients, while all additional thrombectomy attempts were unsuccessful in only one case. In a follow-up examination of our patients a year after surgery, the clinical result was very good for 62%, good for 29% and poor for only 9%, whereby it was possible to obtain this high proportion of unchanged good results for thromboses up to eight days old. The phlebographic examination carried

Fig. 2. Incomplete TEA of external iliac artery with unremovable media/intima cylinder.

VENOUS THROMBECTOMIES The angioscopy findings of 120 operations performed in the period from 1986 to 1990 were evaluated retrospectively from a total of 182 endoscopically-checked venous thrombectomies. The information was complete for 101 patients. Thrombosis affected all three levels in 50 cases, while the pelvic/femoral level was affected in 24 patients and the femoral/tibial level in 13 patients. There was isolated occlusion of the pelvic vein in 14 cases. In cases where the pelvic veins were affected (n = 88), the endoscopic findings refer only to checking of this vascular section, since the femoral vein was checked only sporadically in this constellation. In contrast, the femoral vein was routinely subjected to retrograde endoscopy if the femoral/tibial veins were involved. The procedure for orthograde inspection of the iliac vein is shown in Figure 3. The following procedure has proven itself suitable for retrograde assessment of the femoral vein: the endoscope is positioned in front of the first valve closed, owing to the irrigation pressure. This valve opens as a result of powerful sural compression with simultaneous cessation of irrigation, and the endoscope can then pass the valve site. This method normally allows the device to be advanced into the distal popliteal vein without damaging the valves. Angioscopic monitoring was assessed as insufficient with respect to image quality or as not technically feasible in five cases in the area of the pelvic

Fig. 3. Blood flow interruption and endoscopy after transfemoral venous thrombectomy.

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performed in one group in addition to intraoperative arteriography (Fig. 5). The angioscopic check was insufficient twice, owing to poor vision and was not possible once owing to technical problems out of a total of 65 patients. In the remaining cases, it was possible to examine the whole bypass and distal anastomosis. Three cases of protruding plaques in the distal anastomosis area and five cases of large clots in the

Fig. 4. Relevant residual clots in patient with thrombectomy of the pelvic veins.

out at this time showed complete patency of the vascular sections subjected to thrombectomy for 75% of patients.

FEMOROCRURAL RECONSTRUCTIONS Since October 1983, vascular endoscopy has also been used in infrainguinal reconstructions. Initially, the effects of endoscopic lumen control on the patency rates of conventional femorocrural bypasses were investigated in a retrospective study. After introduction of the in situ technique, angioscopy was also used to check this operation from the middle of 1986 on. The patency rates after infrainguinal revascularizations were calculated in accordance with the guidelines laid down by Rutherford, whereby curve characteristics of different groups were checked for statistically significant differences with the log rank test [5]. Conventional reconstructions

In total, 220 femorocrural bypass operations for limb salvage were recorded between October 1, 1983 and September 30, 1986. Of these, 155 were checked arteriographically only and 65 both arteriographically and endoscopically. The peripheral graft insertion was located distal to the popliteal artery in the proximal third of the leg arteries. Use of the chi-square test did not reveal any significant differences between both groups with respect to age, clinical stage, type of reconstruction and location of the distal anastomosis. After completion of the distal anastomosis, an endoscopic check of the transplant and of the anastomosis was

Fig. 5. Bleeding control and endoscopy for infrainguinal bypass operations.

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352

Fig. 6. Thrombus formation (right) as well as protruding plaque (left) in the area of the distal anastomosis.

bypass, including anastomoses, were found in a total of eight patients (Fig. 6). In spite o f intraoperative correction of these findings, the curve characteristics for both groups (Tables It and III, Fig. 7) did not differ in a statistically significant way (p > 0.05). In situ reconstructions

One-hundred ten femorocrural in situ bypass operations were performed from June I, 1986 to D e c e m b e r 31, 1990. Endoscopic lumen control was carried out in the course of 75 bypass operations for which an angioscope was available, in addition to the arteriographic examination. Ten patients were in Stage III and 98 in Stage IV. The operation was pertbrmed twice with incomplete ischemia owing to a thrombosed popliteal aneurysm. The distal arias-

tomosis was in the proximal half of the leg 45 times and was in the distal half 65 times. Of the latter cases, it was located in the area of the malleoli 16 times. The groups with endoscopic examination and without endoscopic examination (n = 35) were comparable with respect to their composition. Valvulotomes from various manufacturers ~ were used for valve destruction. In one group, orthograde angioscopy of the bypass was performed to assess valvulotomy and to locate the side branches before connection of the anastomoses. Corrections were performed immediately if valve destruction was incomplete. in total, it was possible to view the whole length of 63 bypasses, whereby there were no complaints about vision in any examinations. In the first 20 in situ reconstructions checked in this way, incomplete valvulotomy was assumed for eight patients. In a further 55 such operations, insufficient valve destruction was found in only seven cases (Fig. 8). Conspicuous findings at the distal anastomosis, which was inspected in 20 patients, could not be detected. Localization of all side branches was not completely possible by endoscopy for eight patients, with the result that final arteriography. showed the still remaining arteriovenous fistulae. The results which we obtained with in situ recon-

~American V. Mueller, USA: Braun. Melsungen, Germany: Hell & Co, Switzerland.

TABLE ll.--Primary cumulative patency rates after endoscopically checked infrainguinal bypasses (n = 65) Interval

Grafts at risk

Failure

Withdrawn

Patency rate (%)

Standard error (%)

0--1 2-6 7-12 13-18 19-24 25-30 31-36 37-42 43-48 49-54

65 61 55 51 43 34 30 27 25 20

4 3 3 2 8 0 1 1 0 1

0 3 1 6 1 4 2 1 5 5

94 89 84 81 66 66 63 61 61 57

3 4 5 5 6 7 7 7 8 8

TABLE III.--Primary cumulative patency rates of the control group checked by anteriography (n = 155) Interval

Grafts at risk

Failure

Withdrawn

Patency rate (%)

Standard error (%)

0-1 2-6 7-12 13-18 19-24 25-30 31-36 37-42 43-48 49-54

155 136 101 96 90 69 60 49 35 32

17 16 3 3 13 2 1 3 1 2

2 19 2 3 8 7 10 11 2 2

89 78 75 73 62 60 59 55 53 50

2 3 4 4 4 5 5 5 6 6

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ll~:CttNIQUE AND RESULTS OF VASCULAR ENDOSCOPY

1,0

•

checked endoscopically (n=65)

0,5

~, checked by angiography only (n=155)

0,0

I

t

I

t '¸

-t

-6

-12

I

-18

I

-24

I

-30

I

-36

~

-42

I

-48

-54 months

Fig. 7. Primary cumulative patency rates of endoscopically (n = 65) and arteriographically checked (n = 155) infrainguinal bypasses. (Bars indicate standard error).

Vascular endoscopy has become a valuable method for checking arterial and venous reconstructions since it was introduced in 1982. With respect to applicability, the technique described by us allowed clear vision in all cases for aortoiliac thromboendarterectomies and in 93% of cases for venous thrombectomies. In all these cases, it was possible to inspect the whole disobliterated vascular section. Of 140 endoscopic examinations per-

formed in the infrainguinal area, it was not possible to achieve sufficient visualization for only two patients. H o w e v e r , angioscopy of the whole graft length was possible in only 63 cases from a total of 75 in situ bypasses, in spite of good vision. The reason for this was that only one endoscope with an outer diameter of 2.7 mm (Olympus PF-27L**) was available to us in the initial phase for infrainguinal reconstructions. Consequently, there were frequent problems with the caliber acceptance of the apparatus. While it was normally possible to achieve very good vision in the lumen using the technique employed by us, there were difficulties in about 7% of the venous thrombectomies performed. The reason for this was massive inflow from side branches. The following procedure is nevertheless helpful in permitting assessment of the success of the operation: the endoscope is pushed forward up to the blocking balloon and then pulled back in contact with this. Exact assessment o f the vascular walt is then possible through the transparent balloon, which is in close contact with the wall. Use of the roller pump mentioned above may also guarantee more efficient irrigation in the venous area. We observed vascular damage related directly to endoscopy in only one case. With this patient, the proximal end of a reversed vein bypass was damaged during insertion of the double lumen cannula used for irrigation. Theoretically, angioscopy can

Fig. 8. Incomplete valvulotomy after femorocrural in situ bypass operation.

**Olympus Corporation. Lake Success. New York.

structions are summarized in Table IV and Figure 9. T w e n t y bypass occlusions occurred in the first six months in the group where e n d o s c o p y was performed (n = 75) and 15 in the group where endoscopy was not performed (n = 35). These differences are not significant (chi-square test = 2.89: p > 0.05).

DISCUSSION

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TABLE IV.--Primary cumulative patency rates after femorodistal in situ bypass operations Interval 0-1 2-6 7-12 13-18 19-24 25-3O 31-36 37-42

Grafts at risk

Failure

Withdrawn

Patency rate (%)

Standard error (%)

110 72 48 37 23 2O

26 9 3 4 0 2

12 15 8 10 3 6

75 64 60 52 52 46

3 4 5 6 7 8

12

0

0

46

10

12

0

2

46

10

cause endothelial trauma in the bypass. Hashizume, for example, has been able to observe endothelial injuries in animal experiments; however, these were no longer detectable after a few weeks [6]. He concluded from this that endoscopy can be used safely for diagnostic purposes. In order to prevent endothelial damage, the device is moved in the center of the vessel only when there is sufficient irrigation during angioscopy. The examination is always stopped in the event of wall contact in vessels whose caliber corresponds practically to that of the angioscope. In addition, the irrigation pressure is restricted to 200 mmHg. This also prevents the worst imaginable complication, namely bursting of the vessel wall, something which could occur, for example, with a still functioning valve of an in situ vein and careful central sealing of the endoscope entry point. Although we have not conducted any studies on this, our impression is that endoscopy does not result in increased infection frequency. While the connections for lighting and irrigation fluid at the interfaces to the sterile area, as well as the possible contact between the eye of the examining person and the eyepiece represent weak points from a hygienic point of view, no danger should result from this if work is performed in a disciplined manner, in our opinion, hygienic optimization is possible through the use of a fully sterilizable chip camera,

t

,

±

0,5

I

0,0 -1

-6

-12

"t8

-24

-30

-35

-42 months

Fig. 9. Primary cumulative patency rate of femorodistal in situ bypass grafts. (Bars indicate standard error).

which is connected to the angioscope in a sterile cover. As regards possible fluid overloading of the patient, no risks need be expected for an average irrigation volume of 300 ml in infrainguinal reconstructions. Quantities of > 1000 mt in some cases are required only for venous thrombectomies. However, this operation mostly involves significant blood loss, with the result that the consumed irrigation fluid also does not present any risk to the patient if it is included exactly in the intraoperative fluid balance. The duration of the endoscopic examination was not recorded prospectively. Currently, it takes five to I0 minutes to check aortoiliac TEAs, venous thrombectomies, and conventional femorocrural bypasses. The preparation of an in situ vein with valvulotomy and subsequent endoscopic control with simultaneous localization of the side branches requires approximately 30 minutes. The results of intraoperative angioscopy provided reasons for many corrections and changes in operating tactics in our series. Of 72 thromboendarterectomies, which predominantly affected the external lilac artery, 22 were assessed as incomplete, owing to significant nonremovable intimal flaps, necessitating a bypass operation in these cases. This vessel was thus more problematic to disobliterate than the mostly shorter and wider common iliac artery where ring thromboendarterectomy was unsatisfactory in only one case. Apart from these effects on the operative procedure, we consider 3.3% to be an acceptable immediate occlusion rate for our series of endoscopicallychecked thromboendarterectomies, whereas the figure quoted in the relevant literature is 1 to 13% [7,8]. Using improved instruments for endovascular manipulation or lasers in conjunction with endoscopic vision, it may be possible to perform TEA operations more often in future than is currently possible with conventional ring probes. Overall, our experience correlates with that of Vollmar's working group, which was also not able to achieve complete disobliteration of the iliac arteries in approximately 20% of cases [9]. After venous thrombectomies of the iliofemoral veins, slightly more than half of these operations

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proved to be complete when checked endoscopically, in spite of free catheter passage and good blood reflux. Only after perfbrming additional maneuvers was it possible to achieve acceptable clearance of the clots in a further 36 patients. It is thus possible to achieve a satisfactory thrombectomy in around 90% of patients only with the help of angioscopy. In our opinion, vascular endoscopy has a crucial role in this operative procedure, being superior to intraoperative phlebography as a control method [I0]. With endoscopic vision, it is possible to reliably direct a correspondingly bent thrombectomy catheter into the closed common iliac vein, which had been previously introduced "blind" into the ascending lumbar vein. If a temporary arteriovenous fistula is not generally performed as in our hospital--this should be done at least for initially incomplete thrombectomies, something which is, however, practically only visible through an endoscope. If a venous spur is present, something which can also be detected reliably only by means of endoscopy, the operation should be ended--without further thrombectomy or dilation attempts-and a "Palma operation" considered if a severe postthrombotic syndrome will occur. Correspondingly, our follow-up examinations, carried out one year after surgery, showed a poor clinical result for only 9%, compared with 14 to 39% quoted by other authors [1 I]. We attribute this, as well as the patency apparent in 75% of cases, to the maximal possible completeness of the thrombectomy which can be achieved using angioscopy. Assessment of the findings obtained during angioscopy of femorocrural bypasses has not yet been completed and requires further studies. Although correction of endoscopic findings was performed in eight cases from a total of 65 conventional infrainguinal reconstructions, there was no improvement in patency rates compared with a control group where endoscopy was not performed. It is possible that the findings were overestimated owing to the magnification of the endoscopic image, something which has also been observed by Olcott [12], with the result that unnecessary revision was performed. For this reason, we have now given up general angioscopic examination of conventional bypasses because we do not expect any improvement in results with our increasing experience in crural surgery. Overall, however, it must be stated that vascular endoscopy is superior to intraoperative arteriography for recognition of fine details, since it was possible to see only four of the detected eight abnormalities by means of arteriography as well. Having said this, the study also clearly showed that it is not possible to draw a satisfactory conclusion about the outflow tract with the apparatus we used, because we could not pass the crural arteries with the endoscopes. It is thus also not possible to verify

355

so-called clamp damage which may occur during control of backbleeding in the anastomosis area. Use of the new ultra-thin fiberscopes (diameter 1.4 ram) could remedy this problem, but even these devices will never permit a statement to be made about the plantar arches. It must therefore be recorded that vascular endoscopy, as an additional control method, has not resulted in any improvement in patency for conventional bypasses and has also not been able to displace arteriography, which is still necessary to assess the outflow tract. As regards femorodistal in situ reconstructions, we found incomplete valvulotomy in 40% of a first series of cases by endoscopic examination, a figure which corresponds to that obtained by Grundfest [13]. We explain this high percentage by our initial lack of experience in valvulotomy. Later on, it was possible to reduce the percentage of incompletely incised valves to 12.7%. In our opinion, such relevant valve remnants can be detected reliably only by means of endoscopic examination, particularly since several studies [14,15] have shown residual valves in up to 10% of cases in spite of arteriography being performed without any findings. A further reason in favor of carefully checked vaivulotomy operations is the fact that 26% of early revisions and 27% of late revisions were the result of inadequate valve destruction according to a study by Bandyk [16]. Irrespective of this, we did not achieve any statistically significant reduction in the occlusion rate by endoscopic checking of valvutotomy in the first six months, compared with a group where endoscopic examination was not performed. Nevertheless, we are currently continuing endoscopic monitoring of in situ bypasses, because we, like other authors [13,17-20], still consider this method to be extremely valuable for assessment of valve destruction and because it is additionally very useful for localization of the side branches. In this context, however, it should be combined with intraoperative or postoperative arteriography, because around 10% of tributaries were overlooked, in spite of extreme care being taken.

CONCLUSION We can make the following assessment from our experience with vascular endoscopy: (1) angioscopy represents an easily applicable diagnostic method for vascular reconstructions without recognizable morbidity for the patient; (2) owing to the information obtained with this method, we believe it to be the standard control method for venous thrombectomies and aortoiliac thromboendarterectomies; and (3) even if endoscopic lumen control of infrainguinal reconstructions cannot be generally recommended on the basis of our results, it never-

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theless offers some advantages in conjunction with the in situ technique. I1.

REFERENCES

12.

I. VOLLMAR JF, LOEPRECHT H, HUTSCHENREITER S. Advances in vascular endoscopy. Thorac Cardiovasc Sttrg 1987;35:334-341. 2. LOEPRECHT H, WEBER H, MONNIG J. Vascular endoscopy. In: GREENHALGH RM (ed). Diagnostic techniques and assessment procedures in vascular sar~er.v. London: Grune & Stratton, 1985; pp 303-317. 3. WEBER H. LDEPRECHT H, WOELFLE KD, et al. In: MAURER PC ed). Praktischer Wert der G~[~iendoskopie Iohnt sich der Aufwand? Stuttgart: Thieme Verlag. 1991 : pp 34-44. 4. WOELFLE KD, LOEPRECHT H, WEBER H. et al. lntraoperative assessment of in situ saphenous vein bypass grafts by vascular endoscopy. Eur J Vasc Sltt'li~ 1988;2:257-262. 5. RUTHERFORD RB, FLAN1GAN DP, GUPTA SK. Suggested standards for reports dealing with lower extremity ischemia. J Vase Sttrg 1986:4:80-94. 6. HASH1ZUME M, YANG Y. GALT S. Intimal response of saphenous vein to intraluminal trauma by simulated angioscopic insertion. J Vasc Sltrg 1987:5:862-868. 7. BREWSTER DC. DARLING RC. Optimal methods of aortoiliac reconstruction. SttrL,etT 1978:84:739-748 8. LANGERON P, PHOLSENA P, BARAKAT S. Incidence and causes of early thrombosis after aortoiliac endarterectomy. J Cardiovasc Sttrg 1975:16:362-367. 9. VOLLMAR JF, HUTSCHENREITER S. Vascular endoscopy for thromboendarterectomy. In: MOORE WS (ed). Endovascular Surgeo'. Philadelphia: W.B. Saunders, 1989: pp 87-94. 10. VOLLMAR JF, HUTSCHENREITER S. Vascular endos-

mmll

13.

14.

15, 16.

17.

t8. 19.

20.

ANNALS OF VASCULARSURGERY

copy for venous thrombectomy. In: MOORE WS (ed). Endovascular Surgeo'. Philadelphia: W.B, Saunders, 1989, pp 64-73. WEBER H, LOEPRECHT H. Venoese Thrombektomie: lndikation, Technik und Ergebnisse. Langenbecks Arch Chit" 1988:Suppl.ll: 169-175. OLCOTT C. Angioscopic inspection of an anastomosis: indications and technique. In: MOORE WS (ed). Endovascular Surgeo'. Philadelphia: W.B. Saunders, 1989, pp 50--54. GRUNDFEST WS. LITVACK F, GLICK D. Intraoperative decisions based on angioscopy in peripheral vascular surgery. Ch'culation 1988:78(suppI.l):13-17. BUSH HL, COREY CA, NABSETH DC. Distal in situ saphenous vein bypass grafts for limb salvage: increased operative blood flow and postoperative patency. Am J Sttrg 1983:145:542-548. LEVINE AW, BANDYK DF, BONIER PH, et al. Lessons learned in adopting the in situ saphenous vein bypass. J Vasc Surg 1985:2: 145-153. BANDYK DF, KAEBNICK HW, STEWART GW, et al. Durability of the in situ saphenous vein arterial bypass: a comparison of primary and secondary patency. J Vasc Surg 1987:5:256-268. CHIN AK, FOGARTY TJ. Angioscopic preparation for saphenous vein in situ bypass grafting. In: MOORE WS (ed). Endovascular Surgery, Philadelphia: W.B. Saunders, 1989. pp 74-81. FLEISHER HL, THOMPSON BW, McCOWAN TC. Angioscopically monitored saphenous vein valvulotomy. J Vase Sarg 1986:4:360-364. MEHIGAN JT. SCHELL WW. Angioscopic control of in situ saphenous vein arterial bypass. In: MOORE WS (ed). Endovascular S,rgeo'. Philadelphia: W.B. Saunders. 1989: pp 82-86. SEEGER JM, ABEELA GS. Angioscopy as an adjunct to arterial reconstructive surgery: a preliminary report. J Vasc Surg 1986:4:315-320.