When Echo is Blinded – Quadricuspid Pulmonary Valve presenting with Severe Pulmonary Regurgitation

Description of Clinical Presentation: A 28-year-old female with colon cancer from familial adenomatous polyposis presented with syncopal episodes, progressive exertional shortness of breath, dizziness, and palpitations following a total colectomy 2 months prior. She had a history of congenital pulmonary valve stenosis, status post balloon valvotomy at 1 day old. A transthoracic echocardiogram suggested significant pulmonary regurgitation without a clear etiology or valve anatomy. A cardiac MRI (CMR) showed a quadricuspid pulmonary valve (QPV) with severe regurgitation. Surgical replacement was recommended.

Diagnostic Techniques and Their Most Important Findings: CMR showed a quadricuspid pulmonary valve with severe central regurgitation from leaflet malcoaptation without stenosis, regurgitant volume 48.3 mL, regurgitant fraction 47.9%, dilated right ventricle size (End Diastolic Volume index – 145 ml/m²) with normal systolic function (ejection fraction 54%), main pulmonary artery aneurysm measuring 4 cm, normal left ventricle size and systolic function (ejection fraction 65%), tricuspid aortic valve, and mild mitral and tricuspid regurgitation (Figure 1).

Learning Points from this Case: QPV is a rare congenital anomaly affecting 1 in 400 to 1 in 2,000 people, with a male-to-female ratio of 2:1. It rarely presents with clinical complications like valvular insufficiency or stenosis, making it most often a post-mortem finding.^1-3 QPV has no negative consequences on pulmonary circulation unless it is associated with severe pulmonic valve stenosis or regurgitation.³ Only a few cases of QPV combined with pulmonary artery aneurysm have been reported.^2,4,5 Given the degree of interobserver variability and limited acoustic windows associated with echocardiography, Cardiac MRI is justifiably a Class I indication in the valvular guidelines for quantitation of pulmonary valve regurgitation, right heart size, and right ventricular function if pulmonic regurgitation is suspected to be moderate, severe, or indeterminate.⁶ The patient met a Class I indication for pulmonary valve replacement;⁷ however, immediate surgical intervention was deferred to allow rehabilitation from her recent colorectal surgery. Referral to a valvular center of excellence for percutaneous options was also considered.

A- Steady State Free Precession four-chamber cine showing a dilated right ventricle. B- Steady State Free Precession right ventricular outflow tract cine showing pulmonary artery aneurysm. C- Steady State Free Precession short axis cine showing Quadricuspid Pulmonary valve