Sudden Development of Intraoperative Left Ventricular Outflow Obstruction: Differential and Mechanism. An Intraoperative Two-Dimensional Echocardiographic Study

Abstract

Systolic anterior motion (SAM) of the mitral valve, once considered to be pathognomonic of hypertrophic cardiomyopathy, has been reported in the absence of asymmetric septal hypertrophy. Of the 1,000 open heart operations performed with intraoperative two-dimensional epicardial echocardiography monitoring, four patients developed intraoperative dynamic left ventricular outflow obstruction associated with systolic anterior motion of the mitral valve that was not present preoperatively: three cases of mitral valve annuloplasty with Carpentier ring insertion and one of coronary artery bypass grafting. Though no patient had asymmetric septal hypertrophy or echocardiographic evidence of outflow obstruction by either preoperative cardiac catheterization or echocardiography, intraoperative two-dimensional epicardial echocardiography revealed SAM, and hyperdynamic left ventricles with three of these patients having documented left ventricular outflow tract gradients causing hemodynamic compromise. (Case 4 was hemodynamically stable following mitral valve repair, but had SAM and significant residual mitral regurgitation [MR] requiring reinstitution of cardiopulmonary bypass and re-repair). Measurement of mitral annular dimension demonstrated a normal decrease in size from diastole to systole in control operative subjects but not in the patients who developed outflow obstruction. The pathophysiology, treatment, and role of intraoperative echocardiography of dynamic left ventricular outflow tract obstruction are discussed.

Mitral valve repair with a malleable bovine pericardium ring

“…At a later date, the same group clinically confirmed this by reporting such rings to be a determinant for depressed ventricular function 14 , and supporting the use of malleable rings in carriers of a rheumatic valve pathology with reduced annular contractility, as occurred in 87.6% of the presently studied cases. Furthermore, the rigid ring may also cause the obstruction of the left ventricular outflow tract observed in 4.5 to 10% of the cases [15][16][17][18] , a fact not observed in annuloplasty with completely flexible rings 14,31 or with flexible posterior rings 26,28,29 , results of the present study included.…”

“…These techniques started to be used together with annuloplasty for recovery of valve function 7,12 . Accumulated experience and new concepts about the physiology of the mitral valve apparatus showed the limitations of this technique, such as fixation of the contractile annulus 13,14 and eventual obstruction of left ventricle outflow [15][16][17][18][19] .…”

Catecholamine therapy inducing dynamic left ventricular outflow tract obstruction

“…Additionally, other conditions such as dehydration, sepsis, vasodilatation, or mitral valve repair have been associated with LVOT obstruction [4,5]. Martinez-Useros et al [6] once reported the case of a patient who had a severe fixed stenotic lesion in the left anterior descending coronary artery that led to dynamic obstruction of the LVOT.…”

Mitral valve repair in rheumatic disease. The flexible solution.

“…Of the 316 surviving patients, 42 (Fig 3A). Hazard function for mitral structural deterioration is shown in Fig 3B. Thromboembolism Thirty-eight thromboembolic events occurred in this series, 12 peripheral and 26 central (15 transient, 10 with permanent neurologic impairment, and 1 patient died).…”