P271 Hypoplastic posterior mitral leaflet associated with Marfan syndrome
Authors: Tafciu E , Ancona F , Stella S , Capogrosso C , Ingallina G , Castiglioni A , De Bonis M , Alfieri O , Agricola E 
Published: January 2020

Abstract

A sixty-two years old female presents with shortness of breath. She has Marfan syndrome (c.6448C &gt; T mutation variant) with a previous history relevant for type A aortic dissection which was treated by Bentall procedure with a mechanical aortic prosthesis and ascending aorta prosthesis, coronary artery bypass graft on the right coronary artery and pacemaker for third degree AV block; subsequent aortic arch reconstruction and endovascular repair of the descending aorta for thoracic aorta aneurism rupture.
Upon visit she is in NYHA class III, blood pressure of 145/85 mmHg and heart rate of 75 bpm. A systolic murmur with a prosthetic second tone was heard at heart auscultation and bilateral crackles were heard at pulmonary auscultation. Peripheral pulses were symmetrical. ECG showed sinus rhythm, right bundle branch block with left anterior hemiblock and left ventricular hypertrophy. Blood tests were within normal range. Chest X-ray showed bilateral pulmonary congestion.
She underwent transesophageal echocardiography which showed severe mitral regurgitation (MR) with a normal bi-ventricular systolic function. Posterior mitral leaflet (PML) was severely hypoplastic especially at the level of P1 which was confirmed by CT (see picture). Diuretic therapy together with an ACE inhibitor was introduced with a decrease in MR severity. The patients was sent home with an indication for strict follow up visits.
Congenital mitral valve defects are very rare and can be isolated or associated with other cardiac malformations. Limited data are available about hypoplastic posterior mitral leaflet (PML) including singular case reports or anecdotal descriptions, therefore its etiology, association with other cardiac or systemic syndromes and prognosis is not well understood. However, it is suggested that absence of PML has a high fetal or infant mortality due to severe mitral regurgitation (MR). The degree of MR varies among patients and in the same patient at different timepoints as it depends on anatomical variations of the anterior mitral leaflet, residual PML tissue, posterior ventricular wall conformation and other associated cardiac abnormalities. We showed a case of a patient with hypoplastic PML and advanced age with a concomitant history of Marfan syndrome.

Picture legend
(A) Mid-esophageal 4-chamber view shows severe hypoplasia of PML (red arrow) and the posterior ventricular myocardial shelf (green arrow). (B) Mid-esophageal commissural view shows a large central MR jet. (C) 3D ventricular perspective of the mitral valve: an almost complete absence of the PML can be appreciated in the central and lateral scallops (grey arrows). (D) CT 3 chamber view shows the myocardial shelf which takes the role of the posterior mitral annulus (blue arrow) and direct PML chordal insertion into the ventricular wall (yellow arrow). (E) CT reconstruction of the mitral valve shows a virtually absent P1 (&lt; 1mm), a P2 length of 4.1 mm, and a P3 length of 5 mm.
Abstract P271 Figure. Hypoplastic posterior mitral leaflet