Major determinants and possible mechanism of dobutamine-induced left ventricular outflow tract obstruction in patients with a sigmoid ventricular septum

Abstract

A short leaflet tethering distance ("α") was the major determinant of a latent obstruction, suggesting that a mitral leaflet displacement/redundancy caused by a short "α" distance contributes to the LVOT obstruction.

Harmful effect of epinephrine on postreperfusion syndrome in an elderly liver transplantation recipient with sigmoid ventricular septum

“…Although dynamic LVOT obstruction has been reported in patients with an SVS, [3,5,6,9,10] our present report is the first to document this phenomenon during LT.…”

“…These include a basal interventricular septal thickness >15 mm, a C-sept distance (distance from the mitral coaptation point to the septum) <25 mm, a mitral-aortic angle (angle formed by the intersection of the mitral annulus and aortic annulus) <120°, and an abnormal mitral leaflet length. Another study by Tano et al [3] showed that a short end-systolic leaflet tethering distance (the distance between the tip of the posterior papillary muscle and the contralateral anterior part of the mitral annulus) in the resting state was a major determinant for developing an LVOT obstruction with SAM of the mitral valve leaflets in patients with an SVS during a dobutamine provocation test (29.9 ± 4.2 vs 35.2 ± 4.6 mm). Our present case satisfied most of these provocative conditions.…”

“…In other previous case reports, dynamic LVOT obstructions were provoked in certain hemodynamic settings such as a dobutamine stress test, exercise test, or administration of a phosphodiesterase 3 inhibitor. [3,6] These settings are all associated with increased contractility and a decreased SVR. During LT surgery, recipients undergo a similar but usually more aggravated hemodynamic derangement during graft reperfusion.…”

“…[1,2] This morphological change has been considered a normal aging process involving elongation or tortuosity of the ascending aorta. [1,3] Because an SVS is frequently observed on echocardiography and has no clinical implications in most subjects, not much attention may have been paid to this feature in daily clinical practice. [4] However, in certain clinical circumstances, an SVS has been reported to cause left ventricular outflow tract (LVOT) obstruction, which may result in a severe hemodynamic derangement.…”

“…[4] However, in certain clinical circumstances, an SVS has been reported to cause left ventricular outflow tract (LVOT) obstruction, which may result in a severe hemodynamic derangement. [3,5,6] …”