Regurgitant leak from the area between the stent post and the sewing ring of a stented bovine pericardial valve implanted in the aortic valve position

Biologic valves can sometimes have a small closure or leakage backflow jet originating from the central coaptation point. This is physiologic regurgitation that usually only requires monitoring, and not treatment. Another non-central transvalvular leakage is occasionally seen in both porcine and pericardial valves and originates from the base of the stent post. Typically, it spontaneously decreases or even disappears by the end of the surgery, after administration of protamine. This leak, however, needs to be distinguished from abnormal paravalvular leakages, especially if the regurgitation is relatively large, as this may require an extra cardio-pulmonary bypass (CPB) run. In our case with stented bovine pericardial valves, detailed transesophageal echocardiography (TEE) examination immediately after CPB showed oblique and turbulent flow, which originated from the base of the stent post and flowed toward the anterior mitral leaflet. An extra CPB run, assessment of the cause of the leakage, and restoration if necessary, might have been required if the leakage did not improve or was exacerbated, because contact of the anterior mitral valve leaflet by the oblique flow is associated with the risks of infective endocarditis and hemolysis. Detailed TEE examination accurately delineated the site of the leak, which was subsequently found to originate from the site between the anterior stent post and the sewing ring. The leakage in this case was classified as non-paravalvular, non-central leakage within the sewing ring. Accurate diagnosis of the leakage by intra-operative TEE led to the decision to administer protamine and to adopt a wait-and-watch approach.