Dr. Hartzell Schaff discusses apical myectomy, a new surgical treatment for patients with severely symptomatic apical hypertrophic cardiomyopathy. Dr. Schaff and colleagues presented a study on apical myectomy at the 2009 Annual Meeting of the American Association for Thoracic Surgery.
ABSTRACT
Objective: Apical hypertrophic cardiomyopathy (ApHCM) is a morphologic variant in which the hypertrophy is primarily localized to the apex of the left ventricle (LV). A subset of patients develop progressive drug refractory diastolic heart failure with severely limiting symptoms due to a resultant low cardiac output. Heart transplant has been the only therapeutic option available for such patients. This study analyzes clinical and hemodynamic outcomes of a novel surgical technique to improve diastolic filling by LV cavity enlargement.
Methods: From 1993 through May, 2008, 43 symptomatic patients with ApHCM underwent apical myectomy to augment LV end-diastolic volume (EDV). Information from a prospective database was supplemented by survey information, patient contact, and review of medical records.
Results: The mean age was 50±17yr and 65% were female. All patients were severely limited with dyspnea, 63% had angina, and 60% had syncope or pre-syncope. Ninety-one percent of patients were in New York Heart Association (NYHA) class III or IV. Myectomy was performed through an apical incision, and the LV cavity was augmented by excision of hypertrophic muscle at the apex and mid ventricle; a mean of 16±7 g of muscle was removed. In 14 patients who underwent pre- and postoperative hemodynamic catheterization, the LV end-diastolic pressure decreased from 28±9 to 24±7 mmHg (P=0.002) and the EDV index increased from 55±17 to 68±18 cc/m2 (P=0.003). Invasive measurements of stroke volume increased from of 56±17 cc to 63±19 cc (p=0.007). Forty of forty-one hospital survivors had improvement in symptoms after operation. The mean peak maximum oxygen consumption on exercise testing (n=5) increased from 13.5±4.4 to 15.8±4.6 mL/kg per minute. Survival at 1, 3, and 5 years was 95%, 81%, and 81%, respectively. At an average follow-up of 2.6±3.1years, 23 patients (74%) were in NYHA class I or II. One patient underwent heart transplant 5 years after apical myectomy.
Conclusion: For patients with ApHCM who have limiting symptoms despite optimal medical treatment, apical myectomy can improve functional status by decreasing LV end-diastolic pressure, thus improving the effective operative compliance of the LV and increasing stroke volume. This procedure may be of value in other patients with HCM who have severe hypertrophy and small LV end-diastolic volumes.
Authors
Hartzell V. Schaff1, Morgan L. Brown1, Steve R. Ommen1, Joseph A. Dearani1, Martin D. Abel1, A. J. Tajik2, Rick A. Nishimura1; 1Mayo Clinic, Rochester, MN; 2Mayo Clinic, Scottsdale, AZ
