Reoperative mitral valve replacement: importance of preservation of the subvalvular apparatus

BACKGROUND: Preservation of the subvalvular apparatus has been demonstrated to be beneficial during first-time mitral valve replacement (MVR), but has not been fully examined in reoperative (redo) MVR. The purpose of this study was to analyze outcomes in a large cohort of redo MVR patients, focusing on the effect of subvalvular preservation on mortality. METHODS: We undertook a review of prospectively gathered data on patients undergoing MVR, with or without concomitant cardiac procedures, at our institution from 1990 to 1999. Predictors of mortality were determined by stepwise logistic regression. RESULTS: A total of 1,521 consecutive MVR patients were analyzed, of which, 513 (34%) had undergone one or more previous MV procedures. In-hospital mortality occurred in 6.9% of first-time MVR patients versus 9.0% in redo patients (p = 0.13). The number of prior MV operations ranged from one to five in redo MVR patients, with 115 patients (22% of redos) having two or more. In redo MVR patients, preservation of the native posterior subvalvular apparatus was performed in 103 patients (21%), whereas native anterior and posterior preservation was performed in 31 patients (6%). Gore-Tex neochordal construction was performed in 135 redo MVR patients (26%). Perioperative mortality occurred in 3.6% of redo MVR patients with a preserved subvalvular apparatus (native tissue and/or Gore-Tex reconstruction) versus 13.3% of redo patients without preservation (p < 0.001). Independent predictors of mortality in redo MVR patients were (in decreasing order of magnitude) failure to preserve the subvalvular apparatus, preoperative renal failure, previous stroke/transient ischemic attack, left ventricular dysfunction (left ventricular ejection fraction <40%), and urgent timing. CONCLUSIONS: Redo MVR can be performed with an acceptable risk of mortality. Although preservation of the subvalvular apparatus may increase operative complexity, we recommend subvalvular preservation in order to decrease the risk of early mortality.     

Early aortic bioprosthetic valve deterioration in an octogenarian

We experienced extremely early aortic bioprosthetic valve deterioration with leaflet calcification and stiffening 2 1/2 years after aortic valve replacement in a female octogenarian. We could not identify the possible reason for this devastating complication; however, daily calcium supplement consumption may play a role of acceleration of calcium deposition in the leaflets of implanted bioprosthetic heart valves.     

Intraatrial mitral valve insertion with native valve preservation in children

Two patients underwent intraatrial mitral valve insertion for an unsuccessful valvotomy for severe mitral stenosis and left-sided atrioventricular valve insufficiency associated with corrected transposition utilizing a porcine valve from a valved conduit with preservation of the native valve. The valves were inserted using continuous suture distally at the mitral annulus and proximally at the pulled atrial wall distal to the pulmonary veins. Both patients had uneventful hospital course and are doing well at up to 6 months postoperatively. This approach provides a viable option for congenital mitral stenosis or insufficiency in children.     

Mitral stenosis after mitral valve repair for non-rheumatic mitral regurgitation

BACKGROUND: Mitral stenosis after mitral valve repair for non-rheumatic mitral regurgitation is rare. METHODS: From 1990 to 1999, 478 patients had mitral valve repair for myxomatous and 40 patients had mitral valve repair for ischemic mitral regurgitation. The Carpentier annuloplasty ring (Edwards Lifesciences, Irvine, CA) was used in 72 patients, the Duran ring (Medtronic, Minneapolis, MN) in 152, a posterior band in 221 and no ring or band in 73 patients. RESULTS: Four patients developed mitral stenosis late after mitral valve repair: 2 for myxomatous disease and 2 for ischemic mitral regurgitation. All 4 patients had Duran annuloplasty rings (sizes 25 to 31). The diagnosis of mitral stenosis was made by Doppler echocardiography. The mitral valve area in these 4 patients decreased from 2.7 cm2 (range, 2.3 to 3.2 cm2) early postoperatively to 0.85 cm2 (0.4 to 1.2 cm2) after a mean follow-up of 66 months (range, 38 to 110 months). Three patients had mitral valve replacement and the etiology of the mitral stenosis was the same in all patients (ie, pannus overgrowth on the annuloplasty ring with extension onto both leaflets rendering them stiff and immobile). The fourth patient had a mitral valve area of 1.2 cm2, which was mildly symptomatic with normal pulmonary artery pressure, and this patient has not had reoperation. CONCLUSIONS: Mitral stenosis may develop after mitral valve repair for myxomatous disease or ischemic mitral regurgitation when a Duran ring is used for annuloplasty. The stenosis is caused by pannus on the annuloplasty ring with extension onto the leaflets.     

Clinical outcomes with the Hancock II bioprosthetic valve

Background

The Hancock II bioprosthetic valve, which was first introduced to clinical use in 1978, differs from its predecessor in several ways. This study was designed to evaluate the durability and outcomes with this valve in patients who had isolated aortic or mitral valve replacements.

Methods

From 1991 to 1999, 459 patients underwent aortic valve replacement and 138 patients underwent mitral valve replacement with the Hancock II bioprosthesis (Medtronic Inc, Minneapolis, MN). The mean age was 73.2 ± 0.4 and 72.6 ± 0.8 years in the aortic and mitral groups, respectively. Most patients were in New York Heart Association Class III or IV (50% aortic group and 69% mitral group) and concomitant coronary artery bypass was performed in 49.4% and 52.8% of patients, respectively. Patients were assessed annually and follow-up was up to 129 months in the aortic group and 100 months in the mitral group.

Results

At 8 years, actuarial survival was 52% ± 5% in the aortic group and 57% ± 8% in the mitral group. Furthermore, the actuarial freedom from structural failure necessitating reoperation was 99% ± 0.5% in the aortic group and 98% ± 2% in the mitral group, and the actuarial freedom from repeat valve surgery due to all causes was 97% ± 2% and 96% ± 2%, respectively. Actuarial freedom from thromboembolic events was 89% ± 2% in the aortic group and 90% ± 5% in the mitral group.

Conclusions

The Hancock II valve has excellent midterm durability and clinical performance in older patients.     

Early acute thrombosis of bioprosthetic mitral valve presenting with cardiogenic shock

Early thrombosis of bioprosthetic mitral valves is an extremely rare occurrence. We present an unusual case of a patient with polycythemia presenting with cardiogenic shock, secondary to acute thrombosis of a bioprosthetic mitral valve which was placed 14 months prior to presentation. Our report also reviews predisposing factors and treatment options for bioprosthetic mitral valve thrombosis.     

Robotic "haircut" mitral valve repair: posterior leaflet-plasty

Posterior leaflet prolapse has been repaired traditionally by leaflet resection with or without a sliding annuloplasty. However, substantial annular calcification, thin leaflets, or deficient P1 or P3 scallops can complicate this technique. Annular closure after large posterior leaflet resection introduces substantial radial stress even in the presence of a sliding annuloplasty. We describe a novel technique that corrects posterior leaflet prolapse, minimizes leaflet resection, and preserves posterior leaflet-annulus continuity. This reconstructive technique can be applied in traditional mitral valve repairs but is suited particularly to the robotic approach, in which enhanced visualization and dexterity make the "haircut" repair easy to perform.     

Annuloplasty of the regurgitant mitral valve after myocarditis in children

Acute myocarditis is characterized by the development of rapid life-threatening congestive heart failure and arrhythmias. In many cases with hemodynamic compromise, medical therapy and mechanical support alone are not sufficient. Various surgical procedures have been tried to bridge patients with myocarditis to both transplant and recovery. Mitral regurgitation is a frequent association with end stage cardiomyopathy and predicts poor outcome. Mitral annuloplasty is well-established in adults with ischemic and dilated cardiomyopathy and the results are superior to medical therapy alone and are comparable to cardiac transplantation. However, its effectiveness and use is not well-established in children with cardiomyopathy. We report our experience in two children.     

"Adjustable" artificial chordal replacement for repair of mitral valve prolapse

Achieving a stable repair of mitral valve prolapse can be difficult in complex pathologies, and a 5% to 20% late reoperation rate exists with leaflet resection and reconstruction. During an 8-year period, prolapse was managed uniformly with "adjustable" Gortex (W. L. Gore & Associates Inc, Flagstaff, AZ) artificial chordal replacement and Carpentier ring annuloplasty (Edwards Lifesciences LLC, Irvine, CA), without leaflet resection. Artificial chords were placed initially in the papillary muscles, and then after ring annuloplasty they were adjusted to optimize length to the prolapsing segment(s). Of 52 patients with prolapse, 100% were repaired successfully with artificial chords. Operative mortality was 1.9%, and 4, 6, and 8-year survivals were 87%, 81%, and 71%, respectively. Only 1 of 52 patients (1.9%) experienced late failure, and this patient was re-repaired with artificial chords. Thus, "adjustable" artificial chordal replacement facilitates uniform repair of mitral valve prolapse with a low late failure rate.     

Risk of repeat mitral valve replacement for failed mitral valve prostheses

Background

Advances in tissue prosthetic valve design and manufacturing have stimulated renewed interest in the use of biological valves in younger patients. This approach, however, risks reoperation. We therefore reviewed our recent experience with repeat mitral valve replacement to better define its contemporary risks.

Methods

Using a computerized database, we identified and compared 106 patients undergoing repeat mitral valve replacement with 562 control patients undergoing primary mitral valve replacement between January 1993 and December 2000 at our institution.

Results

There were no significant differences between repeat and primary surgery groups with respect to age (mean 66 ± 12 vs 64 ± 13 years), gender distribution (women 65% vs 64%), preoperative functional class, ejection fraction, or active endocarditis (6.6% vs 3.4%). The indication for reoperation in the repeat group was structural dysfunction in 49 patients (46%), paravalvular leak in 21 patients (20%), nonstructural dysfunction in 11 patients (10%), and progression of other native valve disease in 8 patients (8%). Prior prostheses were mechanical in 46 patients (43%). Mean time to reoperation was 11.5 ± 7.1 years. There were 5 deaths out of 106 patients in the repeat group (4.7%) and there were 23 deaths out of 562 patients in the control group (4.1%) (p = NS). Multivariate analysis identified prior myocardial infarction (p = 0.014, odds ratio 2.9) and nonelective surgical status (p = 0.004, odds ratio 2.3) as significant predictors of operative mortality.

Conclusions

The risk of repeat mitral valve replacement was low suggesting that there should be less reluctance to recommend patients choose a bioprosthesis over a mechanical prosthesis. Given the expected durability of current designs, bioprosthetic use may be explored in younger patients without subjecting those individuals to excessive risk.