Acquired discrete subaortic stenosis late after mitral valve replacement

Abstract

Although acquired left ventricular outflow obstruction has been reported in a variety of conditions, there are scant reports of its occurrence following mitral valve replacement (MVR). This study describes two female patients, who developed severe discrete subaortic stenosis, five years following MVR. In both cases, the mitral valve was replaced by a porcine Carpentier-Edwards 27-mm bioprosthesis with preservation of mitral valve leaflets. The risk of very late left ventricular outflow tract obstruction after bio-prosthetic MVR with preservation of subvalvular apparatus needs to be kept in mind in symptomatic patients.

A novel case of late left ventricular outflow tract obstruction post mitral valve surgery

“…2B) caused further restriction in flow. It is in our opinion that the band will likely have been formed due to turbulent flow from the valve protrusion, though repeated mitral valve prosthesis contact with the interventricular septum has also been shown to cause fibrous material development [4].…”

Congenital, acquired, or both? The only two congenitally based, acquired heart diseases

“…55 Moreover, contact of prosthetic struts with interventricular septum during systole can trigger subendocardial remodeling thus forming the typical fibromuscular "membrane" of DSS. 53…”

“…According to Kalfa et al, 21 32% of patients had mitral valve anatomical lesions before the occurrence of secondary to previous heart operation DSS 21 . Mitral stenosis is also related to secondary DSS 9,53 . The small left ventricle associated with mitral stenosis alters the aortomitral angle leading to increased shear stress in the LVOT and consequent anomalous subaortic fibroproliferative process 53 .…”

“…29 Interestingly, DSS can also develop in adults after acquired heart disease, even more strengthening our thoughts in favor of the acquired nature of the disease. 9,53 Anomalies of the mitral valve apparatus may be associated with DSS possibly due to abnormal flow patterns that may incite abnormal flow patterns in the LVOT. 2,9,54 According to Kalfa et al, 21 32% of patients had mitral valve anatomical lesions before the occurrence of secondary to previous heart operation DSS.…”

Mechanisms, pathophysiology, and diagnostic imaging of left ventricular outflow tract obstruction following mitral valve surgery and transcatheter mitral valve replacement

“…It is thought that in genetically predisposed individuals, abnormal shear stress associated with these geometries triggers a fibroproliferative phenotype leading to membrane formation . It is interesting to note that all prosthetic‐related cases reported to date have occurred in patients with mitral stenosis in whom high‐profile bioprosthetic valves were implanted, factors likely to disrupt normal laminar flow in the LVOT . Whether subclinical DSS was present prior to surgery in these patients, and only became hemodynamically significant because of SMVR‐related LVOT narrowing, cannot however be excluded.…”