Resection, Plication, Release--the RPR procedure for obstructive hypertrophic cardiomyopathy

The surgical management of left ventricular outflow tract (LVOT) obstruction secondary to hypertrophic cardiomyopathy (HCM) has classically consisted of a septal myectomy. To address inconsistent results the extended myectomy or resection (R) and papillary muscle release (R) have been described. Our group introduced a novel addition to the surgical management consisting of an anterior mitral leaflet plication (P). We call the procedure resection - plication- release for repair of complex HCM pathology - the RPR operation. We investigated the mid-term results of all our patients undergoing surgical management for simple and complex HCM pathology.

Forty-two patients have undergone surgery for HCM at our hospital center since we began to look critically at the pathophysiology. Patients received either an extended myectomy alone, a myectomy plus either papillary muscle release or mitral leaflet plication, or the total RPR procedure. Pre and post-operative transesophageal echocardiograms were obtained in all patients to assess LVOT gradient, adequacy of resection and degree of mitral insufficiency. Subsequently, all patients had a trans-thoracic echocardiogram at a mean follow-up period of 3.4 +/- 3.1 years (range, 0.5 to 7).

Twenty-one patients underwent the full RPR procedure; thirteen received portions of the procedure and only seven underwent myectomy alone (including three with concomitant mitral valve replacement (MVR) for insufficiency unrelated to their obstructive pathology). One patient had an isolated MVR as primary therapy for HCM management. The average age was 56 +/-14 years. The preoperative LVOT obstruction gradient was 137 +/- 45 mm Hg and reduced to 10 +/- 17 mm Hg post-operatively. All patients had mitral insufficiency pre-operatively, grade 3.1 on average (scale 0-4), and reduced post-operatively to trivial, grade 0.2. During the follow-up period, LVOT gradient remained low at 6 +/- 14 mm Hg, and mitral insufficiency remained trivial, grade 0.4 (All p values <0.0001). There were no hospital deaths and overall, no need for reoperations.

Hypertrophic cardiomyopathy patients often present with wide anatomic variation. When these variations are understood, the operative approach should be directed to correct or ameliorate those specific aspects, termed simple or complex pathophysiology. Durable long-term results can be achieved in all patients when the mitral valve pathology is appreciated and appropriately repaired, along with a properly located and adequately sized septal myectomy.