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Surgical Repair of the Mitral Valve, 2001

Tomasini, Marcos; Ficarra, Alejandro;
Milano, Santiago; Giordano, Carlos;
Moll, Fernando; Navarini, Emilio;
Pendino, Diego; Tomasini, Germán

Servicio de Cirugía Torécica y Cardiovascular Instituto
Médico Quirúrgico Sanatorio Rosario, Sta. Fe. Argentina
Servicio de Cirugía Torácica y Cardiovascular
Hospital Italiano, Rosario, Sta. Fe, Argentina.

SUMMARY
Introduction: The surgical repair of the mitral valve allows to preserve the subvalvular apparatus, the ventricular function and avoids the long-term complication of the prosthesis itself or the anticoagulant treatment that implies its use.
Objectives: To asses the long term results of the surgical repair of the mitral valve.
Material And Methods: Forty-six consecutive patients were submitted to a surgical repair of the mitral valve by many different surgical procedures. Twenty-six patients (56,52%) were male, 20 (43,48%) were female patients. The age was 52,9+/- 12,16 years (average +/- Standard Deviation) with a range of 27 to 76 years. Preoperatively 2 patients (4,53%) were in functional class II, 27 (58,52%) in class III and 17 (36,95%) in class IV (NYHA). The techniques of valvular repair used were based on the functional approach preconized by Carpentier and Gomez Duran. Twenty patients were submitted to complementary surgical procedures: tricuspid annuloplasty in 10 patients, myocardial revascularization in 7, aortic valve replacement in 3 and manual aortic decalcification in 1.
Results: The perioperative mortality was 4,3% (2 patients). One patient died on the late postoperative period because of bacterial endocarditic of the prosthetic aortic valve and one other patient was reoperated 5 months later because of hemolysis and severe mitral regurgitation. Of the patients who survived the operation, 32 (69,73%) has no mitral insufficiency, 9 (28,26%) has mild insufficiency and 1 (2,01%) moderate insufficiency. All are in functional class I-II.
Discussion. Conclusion: The decision to repair a mitral valve will depend on the surgical experience of the surgical team, the complexity of the valve lesion independently of the etiology, age or functional class of the patient. The feasibility of the repair is of 95% in degenerative, 70% in rheumatic and 75% in ischemic disease. Except in cases of bacterial endocarditic or congenital mitral insufficiency the use of ring is mandatory to stabilize the repair. The transesophaged echocardiograph allows a safe intraoperative assessment.

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INTRODUCTION
   Approximately in the decade of 60, after the beginning of open heart surgery, Lilleher, Merendino and Wooler started the era of surgical repair of mitral valve disease.

   Although the early results were encouraging, the advent of valve prosthesis, the lack of adequate criteria in the selection of patients, reproduction and prediction of the results of the techniques used, caused the abandonment of such techniques giving place to the techniques of valve replacement.

   Years later, with the development of new methods of myocardial protection, Carpenter in France and Gomez Dub an in Spain reported the late results of the so called "Functional approach in the surgical repair of the mistral valve".

OBJECTIVES.
   The aim of present report is to describe our experience in the surgical reconstruction of the acquired mistral insufficiency.

MATERIAL AND METHODS.
   Forty six patients, 28 men (60,9%) and in 18 women (39,1%) were submitted to a variety of surgical procedure to repair and preserve the mitral valve, the average age was 53,26 +/- 12,03 year (SD) with a range of 27 to 76 years. Preoperatively 2 patients (4,3%) were in functional class II, 29 (63%) in class III and 15 (32,7%) in class IV (NYHA). All patients were operated by means of conventional sternotomy with extracorporeal circulation, moderate hypothermia 28°C, antegrade and retrograde crystalloid cardioplegia.

   Once aorta was cross-clamped and the left atrium opened, all three components of the mitral valve, the ring leaflets and the subvalvular apparatus, which may be involved overall or separately were assessed very carefully in order to determine the presence of calcification, thickening, commissural or/and chordal fusion and/or prolapse. The different procedures of valvular reconstruction are detailed in table 1

 

   Once the valve repaired was done and before the atrial closure, the left ventricular cavity was filled with a catheter placed in the apex and connected to the arterial line of the extracorporeal circulation, this allows to assess the valve competence as a first step.

   Twenty patients (43,68%) of 46 were submitted to complimentary procedures to the valve repair, they are detailed in table 2. All patients were evaluated by two dimensional echocardiogram and Doppler color before discharge, every three months or more often if dictated clinically.

   They received oral antiplatelet therapy at discharge from the hospital, except in the presence of atrial fibrillation or giant left atrium, were oral anticoagulation was given during a three month period.

RESULTS
   Two patients (4,4%) died in the postoperative period. One of them, a patient of 56 years old who presented a massive mitral regurgitation, class functional IV dypsnea, pulmonary hypertension with suprasystemic valves and generalized edema, and was treated with a continuos drip of prostaglandin through venous line and noradrenaline infusion by catheter placed in the left atrium, she died suddenly 48 hours later.

   The other patient, a 45 years old male also with class functional IV dypsnea, died of postoperative low cardiac output syndrome.

   Of the 44 patients (95,6%) who survived the operation the follow up period was of 2927,70 month/patient with an average of 66,54 +/- 37,75 months (SD) with a range of 3- 145,8 months.

   The late mortality was of 2,27, a 53 years old male patient died 5 months later because of bacterial endocarditic of aortic valve prosthesis without a mitral regurgitation at the time of death.

   One patient (2,27%) 59 years old man had a peripheral arterial embolism and one patient (2,27%) 69 years old male died at 13 months of sudden death.

   The actuarial survival curve (preoperative and late) was of 91% at ten years. The curve of event free survival (embolization and reoperation) was of 95% at ten years.

   Of the patients who survive the operation and assessed by color Doppler and two dimensional echocardiogram one (2,27%) showed a severe mitral insufficiency that required reoperation 5 months later (just mentioned), 33 (75%) no mitral regurgitation, 10 (22,7%) mild mitral regurgitation and one (2,27%) moderate regurgitation.

   In the postoperative, 29 patients (65,9%) were functional class I, 14 patients class II and one patient (2,3%) was in functional class III.

DISCUSSION.
   The mitral Valve repair in mitral insufficiency when feasible, is undoubtedly superior to mitral valve replacement, because it permits the preservation of the subvalvular apparatus of great importance in the postoperative left ventricular function, avoiding the long term postoperative complications inherent to the valvular prosthesis itself and also to the anticoagulant treatment that its use could imply.

   We have adopted as the therapeutic criteria of repair of the mitral insufficiency the so called functional approach preconized by Carpentier et al. which restores the normal function of the valve more than its anatomy and is based on alterations in the motility of the leaflets, which may be normal (Type I), prolapsed during systole (Type II) or restricted during diastole (Type III). These abnormalities of de valvar motility can present isolated or associated so that the mitral insufficiency is the result of multiple lesions that can involve the distinct components of the mitral apparatus, and they may require multiples techniques, sometimes complex for their correction. In our experience 43 patients (95%) out of 46 two or more procedures were used.

   Except of cares of congenital mitral insufficiency or as secuela of bacterial endocarditic the placement of a ring mandatory in the surgical procedure in order to the repair, prevents the annular dilatation which is progressive that affects selectively the commissure and the posterior leaflet. In the first 9 patients of our series we used the flexible ring of Gomez Duran.

   Later, it was replaced in 24 patients according to physiopathologic concepts just mentioned, we have adopted the use of hemiring advocated by Cosgrove (fig 1-2) or of autologous pericardium treated with glutaraldehyde (fig. 3) and recently of gore-tex (fig. 4). Although the surgical treatment of prolapsed of posterior or mural leaflet (rupture or chordeal elongation is well standardized, Quadrangular Resection), (fig. 5) and its technical simplicity is easily reproducible (21 patients of our series of 46) is not the same with that of the anterior valve in which several techniques has been advised. The chordal transposition has yielded superior results compare to the technique of chordal shortening of Carpentier et al, these procedures mainly the last, poses a high technical challenge and a prolonged aortic crossclamping and in occasions, mainly in advanced rheumatic disease, the chordal tissue may be thick calcified and does not allow a satisfactory repair.

   Recently and following the publication of others authors, we used the replacement of chordal with gore-tex suture. This procedure was applied to 9 patients in our series of 46. The 3 patients of our series treated by means of valve repair with pericardial patch treated with glutaraldehyde suffered a rheumatic disease with localized fibrosis and calcification and was completed with a commisurotomy and ring implantation respectively.

   Although the first assessment of the valve repair may be carried out with the left atrium open filling the left ventricle, watching the line closure and leaflet coaptation paralled to the posterior or mural portion of the ring, which indicates correct competence such assessment is made with a flaccid and relaxed heart, because of that at the present time once the patient is off the extracorporeal circulation we made a more physiological evaluation with the intraoperative transesophageal echocardiography.
The incidence of functional tricuspid insufficiency in mitral valve disease is approximately 20-25% and its correction reduces magnificently the postoperative mortality. Is our policy in those patients with pulmonary hypertension and dilated right cavities, to complete the valve repair with a tricuspid annulopasty, both with the Vega or segmental technique, 11 patients (23,91%) of our series of 46.

   The results achieved in these series of 46 patients with mitral insufficiency are encouraging and the actuarial survival is 91% at ten years and of 95% event free survival.

CONCLUSION
   The decision to repair or not the mitral valve will depend on the experience of the surgical team and its predisposition to do it, like as the complexity of valvular disease more than its etiology, age or functional class of the patient. Nowadays, the feasibility of valve repair is 95% in patients with degenerative disease, 70% with rheumatic and 75% ischemic, as an absolute contraindication we could point out the diffuse fibrosis and calcification in the rheumatic valve disease extense valvular destruction post acute bacterial endocarditic, massive prolapsed of both leaflet myxomatoid disease.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
rbretal@netverk.com.ar
apacher@fac.org.ar
apacher@satlink.com

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