The surgical management of hypertrophic obstructive cardiomyopathy with the concomitant mitral valve abnormalities

The purpose of this retrospective study was to analyse the pathogenesis and the treatment strategies of hypertrophic obstructive cardiomyopathy (HOCM) with the concomitant mitral valve abnormalities.

Between October 1996 and December 2009, 76 patients with the HOCM underwent the ventricular septal myotomy-myectomy in Fuwai hospital. There were 51 males and 25 females aged between 6 and 68 years (mean: 37.18 ± 15.85 years) old. All the patients had left ventricular outflow tract (LVOT) obstruction with a resting or physically provoked gradient of ≥50 mmHg and the systolic anterior movement (SAM) of the mitral leaflets, and 64 patients had mitral regurgitation (MR). These patients underwent the ventricular septal myotomy-myectomy under general anaesthesia and cardiopulmonary bypass. The concomitant surgical procedures included mitral valve replacement (MVR, n = 14) and mitral valve plasty (MVP, n = 12).

All the surgical procedures were technically successful. In comparison with the preoperative conditions, the resting LVOT gradient had marked reduction (99.73 ± 38.61-23.55 ± 16.53 mmHg, P < 0.001), the mean septal thickness was decreased from 26.23 ± 5.24 to 17.33 ± 4.74 mm. MR had significant improvement, SAM was resolved completely or only mild. Four patients (5.3%, 4/76) died during the hospital stay. The causes of death included severe ventricular arrhythmias with low cardiac output, severe acute renal failure, septic shock with acute renal dysfunction and the complete AV block with low cardiac output. The others were followed up for 5-18 years: there were no deaths. Moderate MR was noted in two patients at 2 months or 2 years after operation respectively, who had undergone MVP with the edge-to-edge technique stitch procedure, and only had mild or trivial MR at hospital discharge, of whom one received repeat operation with MVR and the other is still in follow-up. All surviving patients were evaluated as New York Heart Association Functional class I or II, and had a significant increase in physical capacity and a significant reduction in disabling symptoms.

The ventricular septal myotomy-myectomy can be performed successfully for the severe obstructive HOCM and MR with the low morbidity and mortality and excellent survival in the great majority of patients. But for the few patients with the intrinsic mitral valve disease, the concomitant MVP or MVR may be required, and MVR should be performed only as a priority choice for the inherent risks of prosthetic valves and anticoagulation therapy.