Trileaflet mitral valve associated with a bicuspid aortic valve

Abstract

The trileaflet mitral valve is a very rare congenital malformation with three equal size leaflets and three papillary muscles. In this article, we report the first case of trileaflet mitral valve associated with a bicuspid aortic valve in a patient referred for management of infective endocarditis.

<Learning objective: A trileaflet mitral valve is a rare congenital anomaly. There are two cases described in the literature, one associated with hypertrophic cardiomyopathy and the other with a subvalvular stenosis. To the best of our knowledge, we believe that this is the first description of trileaflet mitral valve associated with bicuspid aortic valve.>

Introduction

Congenital malformations of the mitral valve are rare; malformations of the mitral valve involve mitral valve apparatuses and subvalvar apparatuses. The trileaflet mitral valve is a very rare congenital malformation.

We report the case of a patient with infective endocarditis in whom a trileaflet mitral valve associated with a bicuspid aortic valve was detected on the transthoracic echocardiogram.

Case report

A 38-year-old man was referred for management of infective endocarditis. In his past medical history, we noted a rheumatic fever at the age of 16. Recently, he experienced increasing fatigue, stage III dyspnea, and a wrist arthralgia, all evolving in a febrile context. On physical examination, the general condition was preserved. His heart rate was 100 beats/min, Oxygen saturation 99% on room air, and blood pressure 100/60 mm Hg.

He was well perfused with normal and symmetric peripheral pulses. His chest was symmetrical and there were crackling at the base of both lungs. Cardiovascular system examination revealed regular heart rhythm and normal S1 and S2. A grade III ejection systolic murmur was heard maximally at the mitral area, which radiated to the axilla. A diastolic murmur of aortic insufficiency was heard in the third left intercostal space, which radiates along the left sternal border. There was no peripheral edema.

The chest X-ray showed a cardiomegaly predominantly on the left cavities with pulmonary overload signs. The electrocardiogram indicate sinus rhythm and left ventricle hypertrophy.

The transthoracic echocardiogram revealed a dilated left ventricle (end-diastolic diameter 78 mm) and significant aortic regurgitation with suspect mass in aortic sigmoid. A trileaflet mitral valve (Fig. 1A, Supplement 1) with the presence of three equal size leaflets, three commissures (posterior-medial, antero-lateral, and infero-lateral), and three papillary muscles linking the three commissures was seen. A significant mitral regurgitation was associated. The apical four-chamber view showed the normal position of the left ventricle (Fig. 2).

Fig. 1.

(A) Parasternal short axis echocardiographic view demonstrating three mitral valve leaflets wide opened in diastole. (B) Parasternal short axis echocardiographic view of bicuspid aortic valve type-0.

Fig. 2.

Apical four-chamber view showing the normal position of the left ventricle.

Transesophageal Echocardiogram revealed a bicuspid aortic valve Type-0 (Fig. 1B, Supplement 2) on which there were a 20/10 mm vegetation, significant aortic regurgitation, and the presence of trileaflet mitral valve that was confirmed with three papillary muscles (lateral, medial, and posterior) (Fig. 3A and B, Supplements 3 and 4).

Fig. 3.

(A) Short axis transesophageal echocardiography view demonstrating three papillary muscles (lateral, medial, and posterior). (B) Short axis transesophageal echocardiography view showing three mitral valve leaflets wide opened in diastole.

The patient received antibiotic and heart failure treatment. After clinical stabilization and negativity of the inflammatory markers, the patient underwent mitral and aortic valve replacement surgery.

Discussion

The trileaflet mitral valve may be distinguished from isolated leaflet cleft by three equal size leaflets, three evenly spaced commissures, three papillary muscles and central leaflet coaptation [1]. The mechanism of mitral regurgitation is a lack of coaptation of the valve leaflets. There are two cases described in the Literature, one associated with hypertrophic cardiomyopathy and the other to a subvalvular stenosis [1], [2]. To the best of our knowledge, we believe that this is the first description of trileaflet mitral valve associated with bicuspid aortic valve. The Short axis echocardiogram view demonstrates three papillary muscles and shows clearly the three equal size leaflets, separated by three commissures (posterior-medial, antero-lateral, and infero-lateral). The transesophageal echocardiography allows a more precise anatomy study of the mitral valve apparatus and the regurgitation mechanism.

Conflict of interest

The authors declare no conflict of interest.

Appendix A. Supplementary data

The following are the supplementary data to this article: