Acute Severe Aortic Regurgitation Immediately After Cardiopulmonary Bypass Initiation in a Patient With a Bicuspid Aortic Valve.

Antegrade cardioplegia delivery during cardiopulmonary bypass (CPB) is standard practice in cardiac surgery, but it carries a risk of perfusion failure and acute myocardial distension in the presence of aortic regurgitation (AR). In patients with a bicuspid aortic valve (BAV), acute exacerbation of AR can occur immediately after initiating CPB. An 80-year-old man with a bicuspid aortic valve (Sievers classification type 1: L/R fusion), severe aortic stenosis, mild AR, and an ascending aortic aneurysm underwent elective aortic valve replacement and ascending aortic replacement. Immediately after starting CPB and entering ventricular fibrillation (VF), the patient developed sudden, severe AR (vena contracta: 10 mm). This caused rapid left ventricular (LV) dilation and subsequent dislodgement of the LV vent cannula into the left atrium. Real-time transesophageal echocardiography (TEE) promptly identified both the severe AR and the cannula displacement. Following aortic cross-clamping, antegrade cardioplegia failed due to massive regurgitant volume overload into the LV. Prophylactically placed retrograde cardioplegia via the coronary sinus was immediately initiated, successfully achieving rapid cardiac arrest. The planned surgical procedures were completed successfully without further complications, and the patient was discharged in good condition on postoperative day 11. In this patient, the acute exacerbation of AR was likely driven by two key factors: first, a rapid elevation in the transvalvular pressure gradient following CPB onset and VF; and second, the unmasking of latent coaptation failure, stemming from BAV asymmetry and calcification, due to the loss of myocardial tone during VF. Real-time TEE monitoring and prophylactic placement of a retrograde cardioplegia cannula are critical for rapid diagnosis, troubleshooting, and ensuring effective myocardial protection.