Functional Prosthetic Valve Dysfunction: An Underrecognized Cause of Elevated Transprosthetic Gradients

Abstract

Background: Elevated transprosthetic gradients are commonly considered a sign of prosthetic valve obstruction. However, certain haemodynamic or physiological conditions may result in increased gradients despite a structurally normal prosthesis. Recognizing these functional abnormalities is essential to avoid misdiagnosis of prosthetic obstruction and inappropriate management. Aims: To assess the frequency and principal clinical, echocardiographic and aetiological characteristics of functional prosthetic valve dysfunction associated with elevated transprosthetic gradients in a single-centre cohort. Methodology: We conducted a retrospective single-centre study at the Department of Cardiology, Mohammed VI University Hospital, Marrakech, including 77 patients with prosthetic valve dysfunction. Clinical, transthoracic and transoesophageal echocardiographic data, together with laboratory data, were analysed. Functional prosthetic valve dysfunction was defined as elevated transprosthetic gradients in the absence of morphological evidence of prosthetic obstruction, with an identified haemodynamic or physiological condition explaining the increased gradients. Results: Functional prosthetic valve dysfunction was identified in 9 of 77 patients (11.7%). The mean age was 55.9 ± 14.3 years, with a female predominance (66.7%). The main underlying conditions were severe anaemia in 4 patients (44.4%), hyperthyroidism in 2 patients (22.2%), patient–prosthesis mismatch in 2 patients (22.2%), and pregnancy in 1 patient (11.1%). All patients were symptomatic, with NYHA functional class II in 3 patients and class III in 6 patients. The mean transprosthetic gradient was 10.3 ± 1.6 mmHg across mitral prostheses and 30.3 ± 7.0 mmHg across aortic prostheses. No definitive morphological evidence of thrombus or pannus was identified in this subgroup. Conclusion: Functional prosthetic valve dysfunction accounted for 11.7% of prosthetic valve dysfunctions in our series. Severe anaemia, hyperthyroidism, patient–prosthesis mismatch, and pregnancy were the main associated conditions. An elevated transprosthetic gradient should therefore not be interpreted in isolation as evidence of prosthetic obstruction. Its assessment should integrate transvalvular flow, Doppler parameters, the clinical context, and prosthetic valve morphology.