Quadricuspid Aortic Valve Presenting with Aortic Regurgitation in Adulthood: A Case Report

Abstract

Quadricuspid aortic valve (QAV) is a rare congenital cardiac anomaly characterized by four aortic cusps instead of the normal three. It is most commonly associated with progressive aortic regurgitation and is often diagnosed incidentally on echocardiography. A woman in her fifties presented with palpitations and exertional dyspnea (New York Heart Association Class II). Clinical examination revealed an early diastolic murmur at the left sternal border. Transthoracic echocardiography demonstrated a QAV with Hurwitz and Roberts Type F morphology and moderate aortic regurgitation with preserved left ventricular systolic function. Transoesophageal echocardiography confirmed central cusp malcoaptation. The patient was managed conservatively and remained stable at 6-month follow-up. QAV is an uncommon congenital anomaly that may present in adulthood with aortic regurgitation. Echocardiography is essential for diagnosis and classification. Early recognition has important implications for surveillance and procedural planning.

INTRODUCTION

Quadricuspid aortic valve (QAV) is a rare congenital malformation with an estimated prevalence of <0.05%.[1] It is characterized by the presence of four aortic cusps and is most frequently associated with aortic regurgitation. Before the widespread use of echocardiography, QAV was commonly identified incidentally during surgery or autopsy. Advances in transthoracic and transoesophageal echocardiography have significantly improved early detection and anatomical characterization.[2,3]

We present a case of QAV diagnosed in adulthood, presenting with moderate aortic regurgitation.

CASE REPORT

A woman in her fifties presented with intermittent palpitations and exertional dyspnea (New York Heart Association Class II) for 6 months. She had no history of rheumatic heart disease, hypertension, diabetes mellitus, or known congenital heart disease.

On examination, a high-pitched grade 2/6 early diastolic murmur was best heard along the left sternal border. There were no signs of heart failure. Peripheral pulses were normal.

The electrocardiogram and chest radiograph were unremarkable.

Transthoracic echocardiography demonstrated an aortic valve with four cusps, two equal, larger cusps and two unequal, smaller cusps, consistent with Hurwitz and Roberts Type F morphology [Figures 1 and 2]. Color Doppler imaging revealed moderate central aortic regurgitation. Left ventricular systolic function was preserved (ejection fraction 60%) with mild left ventricular dilatation [Video 1]. No associated congenital cardiac anomalies were identified.

Figure 1.

Transthoracic echocardiography with colour Doppler and continuous-wave Doppler interrogation across the aortic valve, demonstrates a central aortic regurgitation jet directed from the aorta into the left ventricle during diastole

Figure 2.

Transoesophageal echocardiography demonstrating a quadricuspid aortic valve morphology. The right panel shows four distinct aortic cusps in systole. The left panel highlights a central noncoaptation zone between the cusps, consistent with malcoaptation leading to aortic regurgitation

Transoesophageal echocardiography confirmed quadricuspid morphology with a central non-coaptation zone contributing to regurgitation [Figures 3, 4 and Video 2].

Figure 3.

The left panel (transthoracic echocardiography, parasternal long-axis view) shows a diastolic regurgitant jet originating from the aortic valve and directed into the left ventricle. The right panels demonstrate a prominent eccentric aortic regurgitation jet with a clearly defined vena contracta at the level of the aortic valve, suggestive of significant aortic regurgitation

Figure 4.

Three-dimensional transesophageal echocardiography reveals four distinct cusps consistent with a quadricuspid aortic valve morphology. The abnormal cusp configuration explains the malcoaptation and associated aortic regurgitation

The patient was managed conservatively with metoprolol and lifestyle modification. Serial echocardiographic follow-up was planned every 6–12 months. At 6 months, she remained asymptomatic with stable echocardiographic findings.

DISCUSSION

QAV is an uncommon congenital anomaly with heterogeneous cusp morphology. Hurwitz and Roberts classified QAV into seven subtypes based on cusp size distribution, with type A (four equal cusps) being the most common variant.[2] Our patient demonstrated type F morphology, characterized by two larger, equal cusps and two unequal, smaller cusps.

The embryological origin of QAV remains unclear. Proposed mechanisms include abnormal septation of the conotruncus, defective fusion of the aorticopulmonary septum, abnormal division of endocardial cushions, and excessive mesenchymal proliferation within the truncus arteriosus.[4,5]

The most common clinical manifestation is progressive aortic regurgitation due to cusp malcoaptation. Symptoms typically develop gradually and include dyspnea, fatigue, and palpitations. Infective endocarditis has been reported, but appears less common compared with bicuspid aortic valves.[6]

Echocardiography remains the diagnostic modality of choice. Transthoracic echocardiography is usually sufficient, while transoesophageal and three-dimensional imaging provide superior anatomical delineation.[3] Cardiac computed tomography and magnetic resonance imaging may assist in preoperative planning.[7]

Management depends on regurgitation severity and ventricular function. Asymptomatic patients with moderate regurgitation and preserved left ventricular function can be managed conservatively with regular surveillance.[8] Surgical repair or replacement is indicated in severe regurgitation or ventricular dysfunction.

With increasing use of transcatheter aortic valve implantation, accurate identification of cusp number and annular geometry is essential. Atypical anatomy may influence prosthesis sizing and increase the risk of paravalvular leak or coronary obstruction if unrecognized.[9,10,11]

CONCLUSION

QAV is a rare congenital anomaly that may present in adulthood with aortic regurgitation. Echocardiography is crucial for diagnosis and classification. Conservative management with periodic monitoring is appropriate in asymptomatic patients with preserved ventricular function. Recognition of QAV has important implications for long-term management and procedural planning.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.