The Unusual Suspect: Anemia-induced Systolic Anterior Motion of the Mitral Valve and Intraventricular Dynamic Obstruction in a Hyperdynamic Heart as Unexpected Causes of Exertional Dyspnea after Cardiac Surgery

Abstract

Dynamic left ventricular (LV) outflow tract obstruction is a characteristic feature of hypertrophic cardiomyopathy; however, it can also occur in association with hyperdynamic LV contraction and/or changes in the cardiac loading condition, even in a structurally normal or near-normal heart. Here, we report a case of anemia-induced systolic anterior motion of the mitral valve and the resultant intraventricular obstruction in a patient who underwent coronary artery bypass grafting and suffered from anemia associated with recurrent gastrointestinal bleeding.

Cardiogenic Shock Secondary to Dynamic Left Ventricular Outflow Tract Obstruction and Apical Ballooning after Nonmitral Cardiovascular Surgery

“…In contrast to the SAM after mitral valve repair, which is a relatively common postoperative manifestation [ 1 , 6 ], SAM that occurs after nonmitral cardiovascular surgery is still an exceptional entity [ 2 , 3 ] and more likely to be missed or not quickly detected as the primary cause of hemodynamic instability. In a patient who underwent a CABG surgery, the principal causes of hypotension would be poor contractility due to cardiac stunning or graft flow abnormality.…”

“…It has been sporadically reported that dynamic SAM occurred in patients with acute coronary syndrome [ 7 ], sepsis [ 8 ], and severe anemia [ 3 ]. Said and coworkers suggested that the thickening of the interventricular septum (bulging subaortic septum) was one of the most important factors of dynamic LVOT obstruction after mitral valve repair [ 9 ].…”

“…The incidence of dynamic systolic anterior movement of the anterior mitral leaflet (SAM) leading to left ventricular outflow tract (LVOT) obstruction after mitral annuloplasty was reported to range between 1 and 16% [ 1 ]. In contrast, SAM in major nonmitral cardiovascular surgery is a rare condition [ 2 , 3 ] but could theoretically worsen an unstable hemodynamics or even trigger a refractory cardiogenic shock. Prompt recognition of this rare presentation is of clinical importance because vasodilators and inotropic agents used in cardiogenic shock can worsen hemodynamics in such patients [ 4 ].…”