Preservação do Aparato Subvalvar Mitral - by Fábio Soares



A preservação do aparato subvalvar mitral durante a cirurgia de troca valvar mitral (TVM), provou ser superior a TVM sem a preservação do mesmo. Ao longo dos anos, a primeira estratégia vem se mostrando benéfica para preservação da função sistólica do VE e para melhora da sobrevida a longo prazo.

Popovic Z, Barac I, Jovic M. Chordal preservation improves postoperative ventricular performance following valve replacement for chronic mitral regurgitation. Cardiovasc Surg 1996;4(5):628–634.

Wu ZK, Sun PW, Zhang FT. Superiority of mitral valve replacement with preservation of subvalvular structure to conventional replacement 

Van der Salm TJ, Pape LA, Mauser JF. Mitral valve replacement with complete retention of native leaflets. Ann Thorac Surg 1995;59:52–55.

Rozich JD, Carabello BA, Usher BW. Mitral valve replacement with and without chordal preservation in patients with chronic mitral regurgitation. Mechanisms for differences in postoperative ejection performance. Circulation 1992;86(6):1718–1726.

Yun KL, Sintek CF, Miller C. Randomized trial of partial versus complete chordal preservation methods of mitral valve

- A prática rotineira desta técnica tem potenciais complicações, como obstruções à via de entrada e saída do VE por interferência entre a prótese valvar e o aparato subvalvar. A obstrução à VSVE ocorre mais freqüentemente devido a implantação de biopróteses de alto perfil; mas também pode ocorrer em próteses mecânicas de baixo perfil.

Bortolotti U, Milano A, Tursi V. Fatal obstruction of the left ventricular outflow tract caused by low-profile bioprosthesis in the mitral valve position. Chest 1993;103(4):1288–1289.

De Canniere D, Janssen JL, Unger P. Left ventricular outflow tract obstruction after mitral valve replacement. Ann Thorac Surg 1997;64:1805–1806.

Melero JM, Rodriguez I, Such M. Left ventricular outflow tract obstruction with mitral mechanical prosthesis. Ann Thorac Surg 1999;68:255–257

- Adicionalmente, alguns fatores de risco para a obstrução à VSVE foram identificados, como uma cavidade ventricular esquerda pequena, hipertrofia ventricular esquerda e hipertrofia do septo interventricular.

Importance of Subvalvular Preservation and Early Operation in Mitral Valve Surgery

(Circulation. 1996;94:2117-2123.)
© 1996 American Heart Association, Inc.
Evelyn M. Lee, MA, MRCP; Leonard M. Shapiro, MD, FRCP; Francis C. Wells, MS, FRCS the Regional Cardiac Unit, Papworth Hospital, Cambridge, UK.

 

Background Mitral valve replacement (MVR) has a high mortality and morbidity. It has been suggested that preservation of the subvalvular apparatus and more optimal timing of surgery might improve outcome.

Methods and Results We performed a retrospective study of 612 consecutive patients who underwent mitral valve repair or replacement: 226 patients had repair, 68 had replacement with subvalvular preservation (MVR/SVP), and 318 had replacement without subvalvular preservation (MVR/NoSVP). Baseline characteristics were most unfavorable in the repair group with respect to age (P=.002) and in the repair and MVR/SVP groups with respect to NYHA functional class and left ventricular function (P=.044). Thirty-day mortality was lower in the repair (1.8%, P=.046) and MVR/SVP (1.5%, P=NS) groups than the MVR/NoSVP group (5.0%). Overall survival at 7 years was better in the repair (71.2±5.6%, P=.022) and MVR/SVP (66.2±12.4%, P=.017) groups than the MVR/NoSVP group (63.5±3.4%). Myocardial failure caused 66 of 107 complication-related deaths. Multivariate analysis confirmed independent beneficial effects of repair on 30-day mortality (odds ratio, 0.27, P<.05) and of repair and MVR/SVP on overall mortality (hazard ratios, 0.43, P<.001 and 0.40, P<.05, respectively) and complication-related death (hazard ratios, 0.38, P<.001 and 0.35, P<.05, respectively). Preoperative NYHA class III or IV symptoms and left ventricular impairment were independent risk factors for death and myocardial failure.

Conclusions Mitral valve repair is superior to replacement. If repair is not feasible, the subvalvular apparatus should be preserved. Early surgery before the development of severe symptoms and demonstrable left ventricular impairment is also needed to optimize outcome.

Mitral valve replacement with total preservation of native valve and subvalvular apparatus.

Aagaard J, Andersen UL, Lerbjerg G, Andersen LI, Thomsen KK.; Department of Cardio Thoracic and Vascular Surgery, Odense University Hospital, Denmark.

J Heart Valve Dis. 1997 May;6(3):274-8; discussion 279-80.

Abstract

BACKGROUND AND AIMS OF THE STUDY: Preservation of the mitral valve and subvalvular apparatus was introduced clinically in the early 1960s, but for two decades the technique for mitral valve replacement included excision of both leaflets and their attached chordae tendineae. Lately, emphasis has been replaced on retaining the mitral subvalvular apparatus during valve replacement because of its role in left ventricular function. Hence, during the past six years, when performing mitral valve replacement we have, when possible, preserved the valvular and sub-valvular mitral apparatus.

METHODS: Between January 1990 and November 1996, complete retention of all mitral tissue in connection with mitral valve replacement was performed in 58 patients (23 women and 35 men). Mean age was 63 years (range: 23 years to 77 years). Coronary bypass was a concomitant procedure in 19 patients; both the mitral and aortic valve was replaced in four cases. Calcified and/or stenotic valves were not a contraindication for the procedure; calcified plaques were removed. Adhesion between anterior and posterior leaflets was treated with sharp dissection. Valve and subvalvular tissue were preserved. The leaflets were reefed within the valve-sutures and compressed between the sewing ring and the native annulus when implanting the valve prosthesis. Chordal tension on the ventricle is thus maintained and the chordae pulled away from the valve effluent.

RESULTS: Six patients died in the postoperative period and three had transient neurological symptoms. In no patient was death or transient neurological symptoms a consequence of the retention of mitral leaflets with subvalvular apparatus.

CONCLUSIONS: We find the described technique to be useful not only in valve insufficiency but also in valve stenosis when preserving the mitral leaflets with sub-valvular apparatus during valve replacement. The technique is without procedure-related complications and prevents obstruction of left ventricular outflow tract.