HOW TO DO IT

A Universally Applicable Continuous Suture Technique for Insertion of Aortic Valve Prostheses J. Cleland, F.R.C.S. ABSTRACT In a series of 55 consecutive patients with both single- and multiple-valvedisease and aortic aneurysm, thiaortic valve was replaced using a continuous suture technique. The technique is applicable for both ball- and disc-valve prostheses. This method resulted in a marked reduction in cardiopulmonarybypass time with a very low incidence of perivalvular leak. It has major advantages over other continuous and interrupted suture techniques.

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echnical advances in prosthetic valve operations which safely reduce the cardiopulmonary bypass time are desirable. A simple continuous suture technique for insertion of aortic valve prostheses is applicable to both disc- and ball-valve prostheses and can be used in patients with calcific and noncalcific aortic valve disease, aortic stenosis or regurgitation, or a small aortic root. The technique results in a considerable reduction in cardiopulmonary bypass time without increasing the incidence of perivalvular leak. The technique depends for its success on the use of polypropylene suture (Prolene),* which has a lower coefficient of friction than other suture materials? and glides through tissue easily with minimal traction. The valve to be inserted is held close to the aortotomy incision so that the aortic annulus is clearly seen, providing one of the advantages of the interrupted technique. The resulting long loops of suture from the prosthetic valve to the annulus are easily pulled down by gentle traction on the free end of the suture without cutting through the tissue annulus or breaking.

From the Cardiac Surgical Unit, Royal Victoria Hospital, Grosvenor Rd., Belfast, Northern Ireland BT12 6BA. Accepted for publication Dec. 1 1 , 1974. 'Ethicon Ltd., United Kingdom. ?The coefficient of friction for monofilament Prolene suture is 0.43; Ethiflex suture (braided Teflon-coated Dacron), 0.55; black braided silk, 0.61; and monofilament Ethilong nylon suture, 0.67. These values were obtained with the use of 2-0 suture drawn through a %-inch thickness of beef muscle. (Data supplied by Ethicon, Inc., Somerville, N.J.)

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Technique The method to be described was that used for the insertion of a Model 2320 Starr-Edwards composite-seat prosthesis.* The heart was approached through a median sternotomy. Cardiopulmonary bypass was instituted by cannulating the ascending aorta for arterial perfusion, and venous drainage was done through a single cannula in the right atrium. A disposable bubble oxygenator was utilized for the entire series.? An oblique aortotomy incision was employed, and coronary perfusion was used in every patient. The heart was decompressed through a left ventricular vent. The perfusion technique has been previously described [13. After excision of the valve, including complete decalcification when necessary, stay-sutures of 2-0 Ethiflext were placed through each of the commissures to improve exposure, as aortic retractors were rarely used. The second assistant held the valve in an inferior position close to the aortotomy incision but not obscuring

A

Technique of suture placement. (A)A continuousover-and-over suture isphcedfirst,from the annulus into the prosthesis and along the edge of the left coronary cusp. (B) The second suture begins at the annulus and continues down the right coronary cusp. *Edwards Laboratories, 17221 Red Hill Ave., Santa Ana, Calif. 92705. ?Disposable bubble oxygenator, Rygg-Kyvgaard, Polystan, Copenhagen. SEthicon Ltd., United Kingdom.

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the view of the aortic annulus. Three double-armed sutures of 2-0 Prolene on a 22 mm taper-cut No. 8977 needle were used for the valve insertion. Commencing at the commissure between the right and left aortic valve cusps, a continuous overand-over suture was begun on the tissue annulus, continuing into the prosthesis and progressing along the cut edge of the left coronary cusp (Figure, A). Loops

C

(C) The third suture completes the suture line. (0) Gentle traction on the sutures gives a tightfit, with the cut edge of the cusps pessed between the prosthesis and the annulus. (LC = left coronary; RC = right coronary; Non C = noncoronary.)

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CLELAND were left as long as necessary, and the prosthetic valve was then displaced upward and held close to the aortotomy incision by the first assistant. A second suture was inserted, again commencing at the commissure between the right and left aortic valve cusps and suturing from the tissue annulus to the prothesis, this time along the cut edge of the right coronary cusp (Figure, B). A third suture was then placed where the previous suture ended at the commi~surebetween the right and noncoronary cusps and was continued along the cut edge of the noncoronary cusp (Figure, C). Only three sutures were needed to complete the suture line. Approximately eight to ten bites were taken along the cut edge of each valve cusp. The ends of each of the sutures were held by a mosquito forceps. At approximately the middle of each of the three suture lines, one of the loops was picked up in a hemostat and withdrawn to give an adequate length for ligation. The prosthesis was then seated on the valve annulus, leaving the valve holder in place. Gentle tension was exerted sequentially on each of the sutures in the line of the cut edge of the cusps so that they fitted tightly between the prosthetic valve and the tissue annulus (Figure, D). It was generally unnecessary to pull up free loops individually. On inspection through the prosthetic valve ring it was easy to see if all loops had been fitted satisfactorily underneath the prosthesis. The circumference of the valve was inspected superiorly to make sure there were no free loops. If there were, they were easily obliterated by gentle traction on the end of the suture. When the seating was satisfactory, each of the sutures was tied. The valve holder was then removed. An identical technique was used for insertion of the Bj6rk-Shiley prosthesis,* but it is a little more difficult to inspect the underside of the prosthetic valve after it has been seated. It is important that the valve holder remain attached to the valve until perfect seating has been assured and the valve has been tied down.

Results The technique was first used in March, 1973, for aortic valve replacement in a series of 33 consecutive patients with single-valve disease and 22 patients with multiple-valve disease. The aortic valve was replaced with a Starr-Edwards composite-seatprosthesis in48 patients and a Bjork-Shiley valve in 7 patients. The sizes of valve inserted ranged from a No. 8 to a No. 13 Starr-Edwards prosthesis and from No. 21 to 23 Bjbrk-Shiley prostheses. The operative mortality was 6% for both single aortic valve replacement (2 of 33 patients) and for mitral and aortic valve replacement ( 1 of 18 patients). Three out of 4 patients who had triple-valve replacement died (75%).At postmortem examination none of the deaths could be attributed to the suture technique, as perivalvular leaks could not be demonstrated. One late death occurred one year postoperatively from dissecting aneurysm. Difficulty with insertion occurred in 5 patients early in my experience. In 4 of these a suture broke during tying. In 3 it was possible to tie the broken ends without difficulty, but for the fourth it was necessary to resuture approximately *Shiley Laboratories, Inc., Santa Ana, Calif

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one-sixth of the circumference of the valve ring, with some difficulty, using a continuous Prolene suture. The fifth patient had a calcified valve and two of the loops cut out of the tissue annulus, making it necessary to resuture one-sixth of the circumference. None of these patients developed a postoperative perivalvular leak. Only 1 patient had clinically detectable evidence of a perivalvular leak. This patient underwent straightforward insertion of a No. 10 Starr-Edwards prosthesis. The aortic valve was heavily calcified, and this may have contributed to the leak. This patient has moderate aortic regurgitation, and although the operation resulted in improvement, the valve will almost certainly need to be replaced. In 15 patients who had single aortic valve replacement with no difficulty in valve excision and with an uncomplicated perfusion, the average bypass time was 60 minutes, a reduction of 40% from the usual perfusion time. Comment Polypropylene (Prolene) has become established as a particularly useful vascular suture material in both coronary artery [21 and peripheral vascular operations [6]. It can be used as a continuous suture for insertion of all types of prosthetic valves in the aortic area. I have also used the material extensively as a continuous suture to insert both ball-valve and disc prostheses in the mitral area. The suture material glides through tissue so easily that each individual loop tightens by gentle traction, eliminating the need for forceps or nerve hooks, which are used in other continuous suture techniques [5, 81. The use of these instruments could weaken the suture line and result in detachment of the prosthesis, as the surface of Prolene is particularly liable to instrument damage and may fracture and break if picked up with forceps or nerve hooks. The technique described can be applied universally, unlike other techniques suitable only for disc-type [3] or ball-valve prostheses [5]. In contrast to other methods, it is unnecessary to remove the ball from the ball-valve prosthesis [S] or to have the prosthetic valve seated when the continuous suture is inserted [3]. The latter could be technically difficult, if not impossible, particularly when inserting a ball valve into a small aortic root. With the method described, even a small ball-valve prosthesis, e.g., a No. 8 Starr-Edwards, can be inserted with ease. Aortic valve calcification is not a contraindication, but it is necessary to take deep bites into the tissue annulus if residual calcification is present. In this series calcification was present in 24 valves and was moderate to severe in 1’7. During insertion, the prosthetic valve is held away from the aortotomy incision so that a clear view of the tissue annulus is obtained for each bite; this is one of the advantages of the widely used interrupted suture technique. It is obviously a much quicker method of valve insertion than the interrupted technique and results in a shorter perfusion time. Only six knots are required to complete the suture line, and theoretically this may help to reduce thromboembolic episodes. The incidence of perivalvular leak after prosthetic valve replacement using the interrupted technique varies between 2.5 and 15% [41. The 2% incidence in VOL. 19, NO. 6, JUNE, 1975

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CLELAND this series compares favorably with these figures and is lower than those reported for other continuous techniques: 4% by Fernandez [3], 3% by Messmer and colleagues 153, and 8% by Wada and co-workers [9]. Perivalvular leak, if it occurs, may be more detrimental, in that a segment of the aortic valve may become detached (although this can also occur when interrupted sutures are used). In my method the suture line is interrupted six times, so that only one-sixth of the circumference would become detached if a segment of suture cut through the tissue annulus or fractured. The technique can also be used with the suture ends tied outside the aortic lumen over pledgets of Teflon [8]. The overall reduction in perfusion time with this technique has encouraged me to consider using hypothermia in preference to coronary artery perfusion, especially because the technique described by Sapsford and associates [7] is so attractive.

References 1. Cleland, J., and Molloy, P. J. Thrombo-embolic complications of the cloth covered Starr-Edwards prosthesis No. 2300 aortic and No. 6300 mitral. Thorax 28:41, 1973. 2 . Ellertson, D. G., McGough, E. C., and Hughes, R. K. End-to-side vascular anastomosis - a modified technique. Ann Thoruc Surg 17:510, 1974. 3. Fernandez, J. Insertion of Bjork-Shiley aortic prosthesis by continuous suture technique. Ann Thoruc Surg 17:587, 1974. 4. Fishman, N. H., Hutchinson, J. C., and Roe, B. B. Prevention of prosthetic cardiac valve detachment. Recent Adv Surg 67:867, 1970. 5. Messmer, B. J., Hallman, G. L., Liotta, D., Martin, C., and Cooley, D. A. Aortic valve replacement: New techniques, hydrodynamics and clinical results. Surgery 68: 1026, 1970. 6. Sanders, R. J. A new monofilament polypropylene suture. ExpMedSurg 28:224,1970. 7. Sapsford, R. N., Blackstone, E. H., Kirklin, J. W., Karp, R. B., Kouchoukos, N. T., Pacifico, A. D., Roe, C. R., and Bradley, E. L. Coronary perfusion versus cold ischemic arrest during aortic valve surgery: A randomized study. Circulation 49: 1190, 1974. 8. Wada, J. T h e knotless suture method for prosthetic valve fixation. Znt Surg 46:317, 1966. 9. Wada, J., Komatsu, S., and Kamata, K. Cardiac valve replacement with Wada-Cutter prosthesis. Ann Thoruc Surg 14:38, 1972.

Addend urn The patients in this study have continued to be followed, and no further paravalvular leaks have occurred. The technique has been used in 18 additional patients without clinically detectable paravalvular leak, including 11 with StarrEdwards prostheses, 2 with Bjork-Shiley valves, and 5 with Hancock heterografts.

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A universally applicable continuous suture technique for insertion of aortic valve prostheses.

In a series of 55 consecutive patients with both single- and multiple-valve disease and aortic aneurysm, the aortic valve was replaced using a continu...
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