Reversible Microvascular Ischemia with ST-segment Elevation: An Underrecognized Manifestation of Antibody-mediated Rejection in Cardiac Allograft Recipients

Electrocardiographic manifestations of cardiac allograft rejection are often subtle, and stress-induced ST-segment elevation associated with antibody-mediated rejection (AMR) is rarely reported. We describe a 34-year-old heart transplant recipient with progressive exertional angina, nonobstructive coronary disease on angiography, and exercise-induced ST-segment elevation in lead augmented vector right, high-lateral leads I, and augmented voltage left, along with diffuse ST-segment depressions, hypotension, and transient ventricular tachycardia. Concurrent emergence of complement-binding donor-specific antibodies with high mean fluorescence intensity raised concern for AMR, prompting treatment with corticosteroids, plasma exchange, and intravenous immunoglobulin despite the absence of biopsy confirmation. After therapy, symptoms, exercise-induced ischemic electrocardiographic abnormalities, and donor-specific antibody levels improved. This case suggests that stress-induced ST-segment elevation may represent a reversible marker of AMR-related microvascular ischemia and highlights the importance of immunologic evaluation in transplant recipients with angina and nonobstructive coronaries.