Objectives: To examine the prevalence of organic mitral valve pathology requiring valve repair, in addition to myectomy in hypertrophic obstructive cardiomyopathy (HOCM) patients and the impact of myectomy on postoperative mitral regurgitation (MR).
Methods: Since January 2005, 80 patients with HOCM underwent septal myectomy due to left ventricle outflow tract (LVOT) obstruction and MR. The mean age was 61±15 (22-85) and 36 were males (45%).
Results: Sixty patients underwent isolated myectomy. Twenty patients (25%) underwent mitral valve repair (8 patients) or replacement (12 patients) in addition to myectomy due to organic mitral valve disease. The mitral valve pathology in this subgroup, was degenerative in 12, rheumatic in 5, one ischemic mitral and two sub-acute endocarditis. The additional reparable lesion was detected by preoperative TEE in 15 patients. In 5 patients evidence of organic MR became apparent only after septal myectomy, and required 2nd pump run to repair (1 patient) or replace (4 patients) the valve.
There was one (1.3%) early mortality. Major complications included 6 patients (7.5%) requiring renal replacement therapy and 6 patients (7.5%) underwent permanent pacemaker implantation.
In the isolated myectomy group, 40 patients (66%) had pre-operative significant MR (at least moderate). Mean echocardiographic follow-up of 31± 24 months, demonstrated, three patient (7.5%) with residual recurrent moderate MR. One with residual LVOT gradient (insufficient myectomy) and two with organic mitral valve disease. The NYHA score have been changed from 2.8±0.5 to 1.9±0.8; The LVOT gradients went down from 55±25 mmHg to 10±14 (p<0.01) ; The MR degree decreased from 2.1 ±0.7 to 1.2±0.8 (p<0.01).
Conclusions: In up to 25% of patients with HOCM and significant MR it may be difficult to predict whether abolishing systolic anterior motion by septal myectomy may also effectively abolish MR. Therefore, the HOCM candidates should be screened for masked organic MV disease by careful preoperative TEE, and with intraoperative TEE following septal myectomy. For patients with HOCM and systolic anterior motion MR, myectomy significantly reduced the degree of MR without requirement for additional mitral valve intervention.
