EFFECT OF THE PRESERVATION OF ANNULO-PAPILLARY CONTINUITY ON LEFT-VENTRICULAR EJECTION FRACTION AFTER MITRAL-VALVE REPLACEMENT - A CLINICALRANDOMIZED STUDY ON PATIENTS AFFECTED BY RHEUMATIC VALVE DISEASE

This perspective study has been designed to evaluate the modifications induced on left ventricular contractility by the interruption of annu lo-papillary continuity during mitral valve replacement in patients wi th rheumatic valve disease. Patients with associated cardiac diseases were not admitted to the study. Sixty-nine patients entered the trial, each patient was randomly assigned to mitral valve replacement either with preservation of the annulo-papillary continuity (PAPC) or with e xcision of all the chordae (EC). Patients with mitral stenosis (MS) an d combined mitral disease (MS & R) were considered separately. The fou r groups were similar regarding preoperative characteristics including the radioisotopic left ventricular ejection fraction (LVEF). All the patients had the mitral valve replaced with a bileaflet prosthesis fix ed by interrupted mattress sutures in the supra-annular position; the methods of anesthesia, cardiopulmonary bypass and myocardial preservat ion were similar in all patients. In the patients of the two EC groups a complete excision of the mitral valve was performed. In the patient s of the PAPC groups a modified Miki's technique was used to preserve annulo-papillary continuity; in eight cases with heavy calcification o f the subvalvular apparatus, after total excision of the mitral valve, PTFE sutures were used to reconnect the annulus to the papillary musc les. After 6 months' follow-up, 2D and Doppler echocardiography was co mpleted in each patient to confirm the absence of any prosthetic leaka ge and left ventricular outflow tract obstruction. (LVOT). In the grou p of MS randomly assigned to EC the radioisotopic LVEF was 51.7 +/- 9 preoperatively and 53.7 +/- 10 6 months after the operation; this vari ation was significantly different (P = 0.03) from the corresponding gr oup in which the APC was preserved (45.5 +/- 10 preoperatively and 54. 1 +/- 10 6 months after the the operation). In the group of MS & R the radioisotopic LVEF changed from 56.7 +/- 12 to 53.9 +/- 12 6 months a fter the mitral valve replacement in the patients assigned to EC, and from 53.2 +/- 9 to 57.4 +/- 9 in patients assigned to PAPC; the variat ion of the LVEF in these two groups was statistically different (P = 0 .02).