Quadricuspid aortic valve

Quadricuspid aortic valve (QAV) is a rare congenital heart defect characterized by the presence of four cusps in the aortic valve, instead of the normal three. This anomaly can affect the valve's function, leading to valve-related complications such as aortic regurgitation (leakage of the aortic valve) or, less commonly, aortic stenosis (narrowing of the aortic valve). The condition is often diagnosed incidentally during imaging studies for other reasons, as many individuals with QAV may remain asymptomatic for years.

Etiology and Pathophysiology

The exact cause of quadricuspid aortic valve is not well understood, but it is believed to result from abnormal valve development during the fifth to eighth week of embryonic life. This developmental anomaly results in the formation of an extra cusp in the aortic valve, which can vary in size and shape compared to the normal cusps. The presence of a fourth cusp disrupts the symmetrical opening and closing mechanism of the valve, potentially leading to valvular dysfunction.

Classification

Quadricuspid aortic valves can be classified based on the size and symmetry of the cusps. The most commonly used classification system was proposed by Hurwitz and Roberts, which categorizes QAV into seven types, ranging from Type A (with four equal-sized cusps) to Type G (with three normal cusps and one smaller, dysplastic cusp).

Clinical Presentation

Many individuals with a quadricuspid aortic valve are asymptomatic and may remain undiagnosed. Symptoms, when present, are typically related to the degree of aortic regurgitation or stenosis and may include shortness of breath, fatigue, chest pain, or palpitations. Severe aortic regurgitation can lead to left ventricular dilation and heart failure if left untreated.

Diagnosis

Diagnosis of QAV is usually made through imaging studies. Echocardiography is the primary diagnostic tool, capable of visualizing the abnormal valve structure and assessing the severity of any associated aortic regurgitation or stenosis. Advanced imaging techniques, such as cardiac magnetic resonance imaging (MRI) or computed tomography (CT), may also be used for detailed anatomical assessment.

Treatment

The treatment for quadricuspid aortic valve depends on the severity of the valve dysfunction and the presence of symptoms. Asymptomatic individuals with mild aortic regurgitation may require only regular monitoring. In cases of significant aortic regurgitation or stenosis, surgical intervention may be necessary to repair or replace the aortic valve. Valve repair is preferred to preserve the patient's own valve tissue, but valve replacement with a mechanical or bioprosthetic valve may be required in some cases.

Prognosis

The long-term prognosis for individuals with a quadricuspid aortic valve varies depending on the severity of valve dysfunction and the success of any surgical interventions. With appropriate management, many individuals can lead normal, active lives.

NIH genetic and rare disease info

• NIH info on Quadricuspid aortic valve

Quadricuspid aortic valve is a rare disease.