Morphological features of mitral annular calcification leading to systolic anterior motion of the mitral valve

Background Systolic anterior motion (SAM) of the mitral valve (MV) can develop after mitral valve repair with placement of an annuloplasty ring. It is occasionally seen in patients with mitral annular calcification (MAC) but mechanisms have not been carefully delineated. Using 2-dimensional echocardiography we explored morphologic parameters which may contribute to SAM in patients with MAC. Hypothesis We hypothesized that in cases of MAC where SAM is present there would be anterior displacement of the valve by the posterior annular calcification. Methods From our echocardiographic database we identified 20 patients with severe MAC who also had SAM with definite septal contact. Each subject was paired with 2 controls free of MAC and 1 control with severe MAC but no SAM. All controls were matched for age, sex, BSA, and septal wall thickness (±1.5 mm). 2-D echocardiographic measurements were taken from the parasternal long-axis (PLAX), apical 3-chamber and apical 4-chamber views. Results MAC+SAM vs MAC no-SAM. Three notable differences were observed: MAC+SAM patients, as compared with MAC no-SAM, had a smaller left ventricular outflow tract (LVOT), longer anterior mitral leaflet, and greater displacement of the MV coaptation point towards the interventricular septum (Figure 1). Median values for these 3 factors were determined using the no-MAC controls; each MAC subject was then scored for number of factors exceeding those values. MAC+SAM patients had a mean score of 2.7 vs 1.1 for MAC no-SAM patients. By combining anterior mitral leaflet length and coaptation point-septal distance as a ratio we could effectively separate MAC+SAM vs MAC no-SAM when >0.9 with one exception (Figure 2). We also observed a smaller anteroposterior annular dimension in the MAC+SAM group. MAC no-SAM vs no-MAC. Comparing these groups there were no differences in LVOT diameter or coaptation-septal distance; effective anterior mitral leaflet length was smaller in MAC no-SAM subjects vs no-MAC controls while anteroposterior dimension of the annulus was larger. Conclusions SAM develops in a subset of patients with severe calcification of the mitral annulus. These patients have a smaller anteroposterior annular dimension, possibly due to severe MAC. Other notable differences characterize MAC patients with SAM from those without. The LVOT is smaller, the effective anterior mitral leaflet length is longer, and the point of leaflet coaptation is displaced towards the septum. Using the ratio of anterior mitral leaflet length/coaptation point-septal distance in this study sample effectively separated those MAC patients with SAM from those without. FUNDunding Acknowledgement Type of funding sources: None. Figure 1 Figure 2

Surgery for Hypertrophic Obstructive Cardiomyopathy: Comprehensive LVOT Management beyond Septal Myectomy

Hypertrophic cardiomyopathy (HCM) is a complex, underestimated, multifaceted disease frequently associated with left ventricular outflow tract (LVOT) obstruction. It is clearly demonstrated that this is due not only to septal hypertrophy but also to systolic anterior motion (SAM) of mitral valve leaflets secondary to mitral valve/subvalvular apparatus abnormalities. Surgical treatment involves performing an extended septal myectomy, eventually followed by ancillary procedures to those structures responsible for maintaining LVOT obstruction, if necessary. In this review, we describe the spectrum of possible surgical techniques beyond septal myectomy and their pathophysiologic rationale.

Systolic anterior motion of the mitral valve associated with acute type A aortic dissection: a case report describing one-step surgery of ascending aortic replacement and interventricular septal myectomy

Background Systolic anterior motion of the mitral valve associated with acute type A aortic dissection is rare in daily clinical practice. The prevention of systolic anterior motion is important, because once it occurs, the hemodynamics may become unstable, leading to a critical situation. In the surgical procedure to treat systolic anterior motion, the prevention of new iatrogenic aortic intimal tears is important in the context of acute type A aortic dissection. Case presentation We present a case of systolic anterior motion in a 68-year-old woman with an acute type A aortic dissection and suspected acute relative adrenal insufficiency. Preoperative transthoracic echocardiography revealed left ventricular outflow tract obstruction due to systolic anterior motion without left ventricular hypertrophy and interventricular septal bulging due to a narrow aorto-mitral angle. We successfully performed a one-step surgery for ascending aortic replacement and interventricular septal myectomy using the needle stick technique for the treatment of systolic anterior motion. Conclusions Concomitant interventricular septal myectomy using the needle stick technique with thoracic aortic replacement is a safe and feasible technique. Interventricular septal myectomy may be effective in preventing postoperative unstable hemodynamics due to systolic anterior motion in the management of acute aortic dissection.

Dynamic thromboembolic left ventricular outflow tract obstruction after aggressive procoagulant treatment in hemorrhagic shock: a case report

Background In cases of hypertrophic obstructive cardiomyopathy (HOCM), the systolic anterior motion of the mitral valve apparatus results in an obstruction of the left ventricular outflow tract (LVOT), which is known as the SAM [systolic anterior motion] phenomenon. Hypothetically, a pathological obstruction of the LVOT of a different etiology would result in a comparable hemodynamic instability, which would be refractory to inotrope therapy, and may be detectable through echocardiography. Case presentation We observed a severely impaired left ventricular function due to a combination of a thrombotic LVOT obstruction and distinctive mitral regurgitation in a 56-year-old Caucasian, female patient after massive transfusion with aggressive procoagulant therapy. Initially, the patient had to be resuscitated due to cardiac arrest after a long-distance flight. The resuscitation attempts in combination with lysis therapy due to suspected pulmonary artery embolism were initially successful but resulted in traumatic liver injury, hemorrhagic shock and subsequent acute respiratory distress syndrome (ARDS). Oxygenation was stabilized with veno-venous extracorporeal membrane oxygenation (ECMO), but the hemodynamic situation deteriorated further. Transesophageal echocardiography (TEE) showed a massive, dynamic LVOT obstruction. Two thrombi were attached to the anterior leaflet of the mitral valve, resulting in a predominantly systolic obstruction. Unfortunately, the patient died of multiple-organ failure despite another round of lysis therapy and escalation of the ECMO circuit to a veno-venoarterial cannulation for hemodynamic support. Conclusion Massive transfusion with aggressive procoagulant therapy resulted in mitral valve leaflet thrombosis with dynamic, predominantly systolic LVOT obstruction, comparable to the SAM phenomenon. The pathology was only detectable with a TEE investigation.