Asian Cardiovasc Thorac Ann 2000;8:189-191
© 2000 Asia Publishing EXchange Pte Ltd
Aortic Valve Replacement With Continuous Suture
Ravi Agarwal, MCh,
Nainar Madhu Sankar, MS, PhD,
Sethurathnam Rajan, MCh,
Rajarathinam Karnan Kalyan Singh, MD,
Kotturathu Mammen Cherian, FRACS
Institute of Cardiovascular Diseases
Madras Medical Mission
Chennai, Tamil Nadu, India
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For reprint information contact: Kotturathu Mammen Cherian, FRACS Tel: 91 44 625 9801 Fax: 91 44 625 9919 or 625 9920 email: mmmbits{at}giasmd01.vsnl.net.in Institute of Cardiovascular Diseases, Madras Medical Mission, 4A Dr. J Jayalalitha Nagar, Mogappair East, Chennai 600050, Tamil Nadu, India.
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Abstract
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A continuous suture technique for aortic valve replacement is described. The technique was used in 462 patients who underwent aortic valve replacement. Hospital mortality was 6.9%. Mild paravalvular leak was seen in 3% and 0.6% needed reoperation for significant paravalvular leak. This continuous suture technique is quick and effective, associated with few postoperative complications, and recommended for patients in developing countries.
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Introduction
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Improvements in surgical results of prosthetic valve replacement have been mainly because of advances in methods of myocardial protection, refinement of surgical techniques, and better prostheses and suture materials. However, these procedures are still associated with significant early mortality and morbidity as well as late complications of prosthetic valve endocarditis, peri-valvular leak, thromboembolic episodes, and prosthesis dysfunction. The preoperative status of the patient, surgical technique, ischemic time, and duration of cardiopulmonary bypass also affect the outcome. In developing countries where most patients present late for surgery and are usually in a decompensated state, good surgical technique can play a vital role. To this end, a continuous suture technique was developed for aortic valve replacement.
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Technique
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All procedures are performed through a median sterno-tomy with standard cardiopulmonary bypass and core cooling to 28°C. Myocardial protection is achieved with antegrade cold blood cardioplegia given directly into the coronary ostia. The aortic valve is exposed through a low transverse aortotomy and stay sutures are applied for exposure. For calcified valves, the left ventricular cavity and left coronary ostium are protected by moist gauze and umbilical tape before decalcification. The aortic valve is excised and debridement and decalcification of the annulus is performed. The annulus is sized and an appropriate prosthesis is selected for implantation. Three commissural stitches are inserted using double-armed 2/0 Ti-Cron suture (Davis & Geek, Wayne, NJ, USA) and a 17-mm needle (Figure 1
). The valve is sutured in place with 2/0 pledgetted double-armed Prolene suture (Ethicon, Johnson & Johnson Ltd, Aurangabad, Maharashtra, India) and a 17-mm needle. The suturing is started in the middle of the right coronary cusp (Figure 2) and both ends of the Prolene suture are passed from the aortic to the left ventricular side through the annulus, with pledgets positioned on the aortic side. The valve is held approxi-mately 5 cm above the annulus and one end of the Prolene stitch is passed sequentially into the valve and aortic annulus and towards the commissure between the right and the left coronary cusps, where it is secured with a rubber-tipped clip. The other end of this Prolene suture is taken towards the commissure between the right and noncoronary cusps. Traction on the previously placed commissural stitches aids visualization of the annulus for placement of the next suture. A second pledgetted Prolene suture is placed in the middle of the left coronary cusp and its ends are taken towards the commissures. Similarly, a third Prolene suture is placed in the middle of the noncoronary cusp and drawn towards the commissural regions. The Ti-Cron stitches placed previously at the 3 commissures are also passed through the annulus of the prosthetic valve. The 2 ends of each Prolene suture are held together and the valve is lowered into position. A nerve hook is used to pull the sutures and any loops are removed (Figure 3). Once the valve is properly seated, the Ti-Cron stitches in the commissural region are tied and triple knotted. The adjacent ends of the Prolene suture are tied (Figure 4A) and this Prolene knot is taken between the ends of the Ti-Cron suture that is tied over the Prolene, thus taking it away from the valve orifice and burying it in the sewing ring of the prosthesis (Figure 4B).
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Figure 1. Placement of the 3 commissural sutures of 2/0 Ti-Cron. LC = left coronary cusp, NC = noncoronary cusp, RC = right coronary cusp.
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Figure 2. Placement of pledgetted 2/0 Prolene sutures in the middle of the cusp and proceeding towards the commissures.
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Figure 4. (A) Ti-Cron and Prolene sutures are tied separately. (B) Prolene suture is buried in the annulus by tying Ti-Cron suture over it.
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Patients
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From June 1987 to March 1996, 462 patients underwent aortic valve replacement using the continuous suture technique. The mean age was 37.4 years (range, 9 to 76 years) and 76.6% were male. Most (86%) were in New York Heart Association functional class II or III and 14% had class IV symptoms. Aortic stenosis was present in 43%, aortic incompetence in 34%, and combined aortic stenosis and incompetence in 23%. There was a high incidence of associated lesions and 42.2% had pulmonary arterial hypertension. Isolated aortic valve replacement was performed in 58.1% of cases and concomitant pro-cedures were carried out in 41.9%. Starr-Edwards valves (Baxter Healthcare, Irvine, CA, USA) were implanted in 228 patients, Medtronic-Hall valves (Medtronic, Inc., Minneapolis, MN, USA) in 101, St. Jude Medical (St. Jude Medical, Inc., St. Paul, MN, USA) in 56, Bjork-Shiley (Shiley, Inc., Irvine, CA, USA) in 55, and various other types of mechanical prostheses in the remaining 22 patients.
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Results
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The aortic crossclamp time for isolated aortic valve replacement ranged from 24 to 56 minutes (mean, 44.3 ± 12.4 minutes). Cardiopulmonary bypass time ranged from 56 to 92 minutes (mean, 67.4 ± 24.2 minutes). In-hospital mortality was 6.9%. Mild paravalvular leak was detected in 3% by postoperative echocardiography. However, 3 patients (0.6%) required reoperation for significant paravalvular leak. No major thromboembolic complications were seen but embolic phenomena were detected in 2 patients taking irregular anticoagulant therapy. Late prosthetic valve endocarditis occurred in 1 patient who ultimately succumbed to infection.
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Discussion
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The continuous suture technique using 3 sutures has the following advantages over the interrupted suture tech-nique: shorter crossclamp and cardiopulmonary bypass times; secure placement; no reduction in annular size; fewer knots, leading to less physical damage to the annulus, valve prosthesis, and aortic wall; and reduced incidence of thromboembolism and prosthetic valve endocarditis by less exposure of the blood to foreign material. The low postoperative mortality and morbidity in this series are attributed to reduced aortic crossclamp and cardio-pulmonary bypass times. Cleland1 found a 40% reduction in bypass time with a continuous suture technique. Hjelms and colleagues2 reported mean aortic crossclamp and bypass times of 52.5 and 79 minutes, respectively, for their continuous suture group, whereas these were 77 and 101.5 minutes, respectively, in the interrupted suture group.
A similar technique was reported by Cooley.3 However, the use of 3 sutures in the method described here, aids correct alignment of the sewing ring to the annulus without any crowding or pursestring effect along any section of the aortic annulus. With this technique, the suture margin was effectively everted, ensuring secure placement of the prosthesis. In this series, 57% of patients had aortic regurgitation alone or combined with aortic stenosis. Aortic regurgitation was noted by Wada4 to be associated with a high incidence of perivalvular leak (26%). Fishman and colleagues5 and Bedderman and Borst6 reported that a continuous suture technique for aortic valve replacement predisposed to perivalvular leak but our results show otherwise.
By using a single pledget at the aortic side of the suture margin, it was always possible to insert an adequate size of prosthesis because the lumen of the annulus was not compromised, in contrast to the use of multiple pledgetted sutures.3 However, a calcified annulus is a problem that even in the best hands demands highly skilful placement of sutures and careful tightening of knots.3 We feel that the pledgets used in this technique prevented the sutures from cutting through calcified annuli and contributed to the low incidence of perivalvular leak.
Much has been said about the potentially thrombogenic "tooth brush" of multiple knots around prostheses.7,8 We buried the knot of the Prolene suture in the sewing ring of the prosthesis with the help of the commissural Ti-Cron stitches, hence very little suture material protruded into the aortic lumen to form a nidus for accumulation of platelets or growth of bacteria. We consider that this technique is quick, secure, associated with few post-operative complications, and especially suitable for patients in developing countries. It is reproducible and combines the advantages of interrupted as well as continuous suture techniques.
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References
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Cleland J. A universally applicable continuous suture technique for insertion of aortic valve prostheses. Ann Thorac Surg 1975;19:719–24.[Abstract]
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Hjelms E, Vilhelmzen R, Rygg IH. Continuous suture technique in prosthetic aortic valve replacement. J Cardiovasc Surg 1982;23:145–8.[Medline]
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Cooley DA. Simplified techniques of valve replacement. J Card Surg 1992;7:357–62.[Medline]
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Wada J. The knotless method for prosthetic valve fixation. Int Surg 1966;46:317–22.[Medline]
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Fishman NH, Hutchinson JC, Benzon BR. Prevention of prosthetic cardiac valve detachment. Surgery 1970;67: 867–73.[Medline]
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Bedderman C, Borst HG. Comparison of two suture techniques and materials: relationship to perivalvular leaks after cardiac valve replacement. Cardiovascular disease. Bull Texas Heart Inst 1978;5:345–9.
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Doty DB, Nelson LRM. Aortic valve replacement: con-tinuous suture technique. J Card Surg 1986;4:379–82.
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Laks H, Pearl JM, Barthel SW, Elami A, Sorenson TJ, Milgalter E. Aortic valve replacement using a continuous suture technique. J Card Surg 1993;8:459–65.[Medline]
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Abstract
Introduction
