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J Thorac Cardiovasc Surg 2004;127:645-653
© 2004 The American Association for Thoracic Surgery
Surgery for acquired cardiovascular disease |
a Division of Cardiovascular Surgery, Mayo Clinic and Foundation, Rochester, Minn, USA
Read at the Eighty-third Annual Meeting of The American Association for Thoracic Surgery, Boston, Mass, May 4-7, 2003.
Received for publication June 11, 2003; revisions received August 15, 2003; accepted for publication September 12, 2003.
* Address for reprints: Hartzell V. Schaff, MD, 200 First Street SW, Rochester, MN 55905, USA
schaff{at}mayo.edu
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Abstract |
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 Top Abstract Patients and methodsResultsDiscussionReferences |
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METHODS: We retrospectively reviewed 160 consecutive patients (127 men) who underwent aortic valve repair between 1986 and 2001. Ages ranged from 14 to 84 years (mean 55 ± 17 years). Patients were categorized according to the main etiology of valve disease; 63 patients (39%) had annular dilation leading to central leakage, 54 (34%) had bicuspid valve, 34 (21%) with tricuspid valve had cusp prolapse, and 9 (6%) had cusp perforation. Repair methods included commissural plication (n = 154, 96%), partial cusp resection with plication (n = 47, 29%), resuspension or cusp shortening (n = 44, 28%), and closure of cusp perforation (n = 10, 6%).
RESULTS: There was 1 early death (0.6%). Two patients required re-repair of the aortic valve during initial hospitalization. During a mean follow-up of 4.2 years, there were 16 late deaths. Overall, 16 of 159 hospital survivors had late reoperation on the aortic valve (mean interval 2.8 years) without early mortality. Risks of reoperation on the aortic valve were 9%, 11%, and 15% at 3, 5, and 7 years, respectively.
CONCLUSIONS: Aortic valve repair can be performed with low risk and excellent freedom from valve-related morbidity and mortality. Late recurrence of aortic valve regurgitation led to reoperation in 8.8% of patients, but mortality associated with subsequent procedures is low. Aortic valve repair appears to be a good option for selected patients, particularly young patients who wish to avoid chronic anticoagulation with warfarin.
Indeed, data from several centers indicate that survival and functional outcome after mitral valve repair are superior to outcomes following mitral valve replacement; however, overall experience with repair of aortic valve regurgitation is relatively small, and reported series include patients having primary valve disease as well as aortic valve regurgitation secondary to disease of the ascending aorta or ventricular septal defect.4,7-9 As is true for the mitral valve, etiology of valve regurgitation would be expected to have a strong influence on outcome of aortic valve repair, especially on late risk of reoperation.10-12 The aims of this study were to assess the early and late outcomes of valve repair in patients with aortic valve regurgitation particularly as regards incidence and risk of reoperation.
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Patients and methods |
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TopAbstractPatients and methodsResultsDiscussionReferences |
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We reviewed Mayo Clinic charts and operative records to identify the patient characteristics, etiology of valve disease, operative techniques, and surgical results. Late outcomes were determined from Clinic records when available or from written correspondence with patients' physicians and direct patient contact with mailed questionnaire or telephone interviews when necessary. Clinical and echocardiographic data at latest follow-up were collected by contacting referring physicians. This study was approved by the Mayo Foundation Institutional Review Board, and patients or families gave informed consent.
Patient demographics
Of the 160 patients, 127 (79%) were men, and ages ranged from 14 to 84 years (mean 55 ± 17 years). Important associated cardiovascular problems included systemic hypertension (n = 56, 35%) and coronary artery disease (n = 33, 21%), congestive heart failure (n = 27, 17%), infective endocarditis (n = 12, 8%), and prior myocardial infarction (n = 9, 6%). Eight patients (5%) were found to have systemic diseases including Takayasu's arteritis in 3, systemic lupus erythematosus in 2, giant cell arteritis in 1, Kawasaki's disease in 1, and juvenile rheumatoid arthritis in 1. Nine patients (6%) had undergone cardiovascular operations prior to aortic valve repair including repair of aortic coarctation (n = 3) or other procedures. As regards functional status preoperatively, 44 patients (28%) were in New York Heart Association (NYHA) functional class I, 50 patients (31%) were in class II, 63 (39%) were in class III, and 3 (2%) were in class IV.
Surgical indications and echocardiographic findings
Most patients were referred for operation because of severe aortic valve regurgitation. Other indications for operation included aortic valve regurgitation in patients referred for repair of severe mitral valve leakage and moderate or severe aortic valve regurgitation in patients with severe coronary artery disease who required revascularization. In the latter patients, the decision for aortic valve repair was made intraoperatively with information from transesophageal echocardiography. Transesophageal Doppler echocardiography was used to judge adequacy of repair intraoperatively, and transthoracic Doppler echocardiographic studies were performed routinely prior to hospital dismissal.
Operative techniques and classification of main etiology of aortic valve regurgitation
All patients underwent operations via median sternotomy with cardiopulmonary bypass established through ascending aortic cannulation and single or bicaval venous cannulation with normothermia or mild hypothermia. Profound hypothermia was used in 4 patients who required circulatory arrest for proximal aortic arch reconstruction. The mean aortic crossclamp and cardiopulmonary bypass times were 46 ± 20 and 64 ± 33 minutes, respectively.
The patients were categorized into 4 groups according to etiology of aortic valve regurgitation:
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Results |
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TopAbstractPatients and methodsResultsDiscussionReferences |
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Two patients had reoperation for aortic valve re-repair during initial hospitalization. In each patient, routine predismissal transthoracic echocardiography identified significant new aortic valve regurgitation compared with that present intraoperatively at the conclusion of repair. Both patients had bicuspid aortic valves and were found to have dehiscence at the plication sutures on the conjoint cusp. Re-repair by resuturing the cusp was successful with satisfactory late results.
Other nonfatal complications included exploration for bleeding in 3 patients (1.9%), neurological event in 3 (1.9%) and respiratory failure in 3 (1.9%).
Preoperative and postoperative echocardiographic evaluations of the aortic valve are summarized in Table 2. Notice that in 11 patients, significant aortic valve regurgitation was missed by the prebypass echocardiographic study.
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Late reoperation and other valve-Related complications
Seventeen patients required late cardiovascular operations, and 16 of these had aortic valve replacement (Table 3); 1 patient had thoracoabdominal aortic aneurysm repair. Mean interval between initial operation and late aortic valve reoperation was 2.8 ± 2.5 years. Among patients having late aortic valve reoperation, the etiologies of aortic valve regurgitation at the initial operation were bicuspid valve in 6 patients, annular dilation in 5 patients, and cusp prolapse of tricuspid valve in 5 patients. No patients having repair of cusp perforation required late reoperation.
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Among the 143 late survivors, 27 patients (19%) were receiving warfarin for various reasons, including thromboembolism prophylaxis for a mechanical prosthesis (aortic or mitral position, n = 14), chronic atrial fibrillation (n = 6), history of deep venous thrombosis (n = 3), and history of stroke (n = 2). The indication for anticoagulation was unknown in 2 patients. Of the 130 patients who at most recent follow-up were alive with their original aortic valve repair, only 11 (8.5%) were on warfarin.
Follow-up Doppler echocardiographic data were obtained from 104 of 130 survivors (free from death and aortic valve reoperation). The mean interval between the date of operation and the date of most recent transthoracic echocardiogram was 2.8 years. Degrees of aortic valve regurgitation were severe in 2, moderately severe in 3, moderate in 26, trivial to mild in 62, and none in 11. There were no patients with hemodynamically important aortic stenosis (Table 2).
At last contact, 107 patients (75%) were in NYHA class I, 30 (21%) were in class II, and 5 (3%) were in class III.
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Discussion |
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TopAbstractPatients and methodsResultsDiscussionReferences |
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In contrast to the situation with degenerative mitral valve disease, where repair is the rule rather than the exception, operation for chronic aortic valve regurgitation usually leads to prosthetic replacement, and concerns of clinicians regarding late complications of prostheses only reinforces a conservative clinical approach to patients.
Most previous reports of aortic valve repair have included patients with acute and chronic aortic dissection,14 annuloaortic ectasia,15,16 or congenital heart problems,5,7 and the role of repair for primary aortic valve disease is not well defined. The present study provides information on the safety and durability of aortic valve repair in such patients. Although patients in this series were highly selected, the very low operative mortality compares very favorably with contemporary reports on risk of aortic valve replacement with biological and mechanical heart valves.1,2,17-20 Surely, there is no suggestion that early mortality is increased with valve repair. Our study population did not include those patients in whom an initial attempt at valve repair was unsuccessful and immediate conversion to prosthetic valve replacement was undertaken. There were few such patients during the study interval, and there were no operative deaths related to an initial attempt at aortic valve repair.
The late results of aortic valve repair that have been presented should be interpreted in the context of expected results from prosthetic valve replacement. Certainly, replacement with a mechanical or a biological prosthesis would be expected to have a lower rate of reoperation during the first 5 to 7 years postoperatively, but this durability comes at the expense of valve-related complications, which, for mechanical valves, occur at a rate of approximately 5% per patient-year.21 In this series, the linearized rate of thromboembolism, anticoagulant-related bleeding, and infective endocarditis combined was 1.0% per patient-year.
Thromboembolism and anticoagulant-related bleeding after aortic valve replacement are lower with biological valves than with mechanical valves, but structural valve deterioration is predictable with heterografts, and rates of valve failure at 10 years postoperatively are 13% to 30% for patients in their fifth decade of life and 18% to 25% for patients in their sixth decade.22-24 Although our follow-up is not sufficiently long to allow formal comparison, durability of valve repair appears similar to that of porcine heterografts in younger patients and offers some hope of function beyond 15 years. In the present series, the mean age of the patients was 55 years with a freedom from reoperation of 85% at 7 years; additional observation will be necessary for secure conclusions regarding durability in comparison to heterograft prostheses.
Also, it should be recognized that these results represent the learning curve for this procedure, and experience in selection of patients and operative methods might be expected to improve subsequent results. For example, early failure resulting from suture dehiscence at the repair site of the bicuspid valve has not occurred since 1997, and late breakdown at the repair site was the cause of recurrent valve leakage in only 1 of the 14 patients who had late aortic valve replacement for aortic valve regurgitation.
The important influence of the learning curve on late outcome is illustrated in Figure 5, which shows the cumulative risk of reoperation after mitral valve repair at our institution during 2 decades. Rates of late reoperation have been reduced by half in the latter portion of this experience. Indeed, the risk of late reoperation after aortic valve repair is very similar to the risk of late reoperation following mitral valve repair involving the anterior leaflet in the 1980s.25
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In conclusion, aortic valve repair in patients with aortic valve regurgitation can be performed with very low mortality and morbidity. Intermediate-term follow-up suggests that valve-related complications are very low and risk of reoperation is acceptable, particularly when compared with the anticipated risk of structural valve deterioration of heterograft valves in young patients.
Discussion
Dr Lawrence H. Cohn (Boston, Mass). This is a very interesting article, very well presented by Dr Minakata, who is a member of one of the premier valve surgery groups in the United States, if not the world, the Mayo Clinic. They took a look at 15 years of data and accumulated 160 patients; that is about 10 to 12 patients per year. My first question to you is this. Is this rate of repair increasing, decreasing, or staying the same, and what might be the denominator per year, approximately, that this fraction represents?
Dr Minakata. During the same time range, approximately 4000 patients underwent first-time aortic valve replacement due to aortic valve disease. Of those, 1250 patients underwent aortic valve replacement due to severe aortic valve regurgitation. The repair rate is increasing for probably the last 5 years.
Dr Cohn. At the Brigham last year we probably did something in the range of 5 to 8 such operations, and I certainly agree that in any noncalcified valve in any form, whether it be bicuspid or tricuspid, aortic valve repair should certainly be considered, but what is not clear to me and maybe to you is your degree of comfort with calcification of the valve. In other words, were any of these valves partially calcified, moderately calcified? What is your comfort level with repairing a valve that is moderately calcified?
Dr Minakata. If there is any significant aortic stenosis, we prefer not doing repair of the aortic valve. In terms of the degree of calcification of the valve, if we resect the calcified portion of the conjoining cusp and still have enough tissue to sew and plicate, I think we can still try the repair.
Dr Cohn. Another question is, how do you test for competence of your repair prior to closing the aorta?
Dr Minakata. Literally, there is no way to evaluate the repair appropriately before closing the aortic wall.
Dr Cohn. No way to do that? Would Dr Schaff like to comment on that maybe?
Dr Hartzell V. Schaff. Evaluation of the repair is more difficult with the aortic valve than with mitral valve repair because the aortic root is relaxed and it is not possible to inspect the valve under physiologic pressure. After repair of a bicuspid valve, you can displace the 2 commissures and check for good central apposition of the cusps, but often you have to wait until the aorta is closed to assess valve competence.
Dr Cohn. My final question is, do your good results suggest to your team that in patients in whom you are doing mitral valve repair that oftentimes have moderate aortic regurgitation, should you be more, shall we say, "aggressive," in repairing those aortic valves along with the mitral valves?
Dr Minakata. For the last question, interestingly, if we exclude the patients who had both mitral and aortic valve repair, the risk of reoperation at 5 years would be about 6% versus 11% in entire series of our paper. If patients have both diseases, mitral and aortic valve regurgitation, they might not be good candidates for this repair.
Dr. Robert A. Dion (Leiden, The Netherlands). I congratulate you for this magnificent paper, and I would like to ask you which technique you would prefer in the presence of a prolapse of 1 of the cusps of a tricuspid aortic valve. We favor the reinforcing of the free edge with a continuous suture of 7-0 polytetrafluoroethylene (Gore-Tex; W. L. Gore & Associates, Inc, Flagstaff, Ariz) above the triangular resection. What would you recommend for the monocusp failure?
Dr Minakata. There were only a couple of patients who had a triangular resection in the tricuspid aortic valve patients. We usually plicate using the commissural plication under each commissure of the prolapsing cusp so that we could decrease the length of the free edge and increase the coaptation area, and oftentimes we also do what we call a "Trusler stitch" to shorten the cusp. Those are the main techniques we usually use.
Dr Schaff. Let me add to that, Dr Dion. We have used primarily 3 methods: 1 would be a Trusler stitch to shorten the free edge of the cusp near the commissures; another would be a very limited triangular resection; and the third maneuver would be to support or resuspend the free edge of the cusp, as you describe, with a suture passed from outside the aorta inward and then along the free edge; we usually use 5-0 polytetrafluoroethylene for cusp resuspension.
Dr Christophe Acar (Paris, France). Congratulations, Dr Minakata. I wish to ask you a question concerning the identification of the mechanics of aortic regurgitation. In your article you mentioned that you had 40% of patients with annulus dilatation. We find it very difficult to identify, especially on the aortic valve. So could you tell us, how do you know that the mechanics of aortic regurgitation were precisely annulus dilatation rather than cusp retraction or rather than dilatation of the sinotubular junction, and did you evaluate this using transesophageal echocardiography or any other method?
Dr Minakata. Essentially we excluded the patients who had dilatation of the sinotubular junction or annuloaortic ectasia from this series. With patients who had tricuspid valve and annular dilation, usually we felt that the main reason for regurgitation was spreading out the cusps toward the outside of the annulus. This is what we usually see in the elderly patients. The regurgitation was almost always central and due to essentially dilatation of the annulus.
Dr Schaff. I might add that, as Dr Minakata mentioned, this series does not include patients with dilatation of the sinotubular junction. Those are easily repaired by inserting a tube graft or narrowing that segment of the aorta. For patients with tricuspid valves and annular dilatation, we don't have specific formulas to determine the extent to which the annulus can be reduced. In practice one often has to place those plication sutures and see if you then have good central apposition of the three cusps. We don't use any formulas or specific guidelines of measurement.
Dr A. Sampath Kumar (New Delhi, India). Were there any cases in which the aortic repair failed on the table and how did you detect and treat this?
Dr Minakata. We encountered 2 early re-repairs. Both patients had bicuspid valves that were found to have dehiscence in the plication sutures on the conjoining cusps. We always try to make a smaller resection in the conjoining cusps with probably 30% of length of the height of the cusp so that we could avoid the tension of the suture lines. And we also had 2 patients who had to go back on cardiopulmonary bypass to have a better repair after initial repair, but all patients had satisfactory results of the additional repair or re-repair of the aortic valve.
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Acknowledgments |
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References |
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TopAbstractPatients and methodsResultsDiscussionReferences |
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