In traditional coronary artery disease, patients often experience symptoms such as angina. However, heart transplant patients lack nerve connections in the transplanted heart and therefore usually do not notice any symptoms. For this reason, routine examinations are performed using traditional coronary angiography at one, three, and six years after transplantation, sometimes with the addition of coronary ultrasound.

A new technique, photon-counting computed tomography, has now been developed and may potentially replace both traditional coronary angiography and intravascular ultrasound. In this study, we aim to investigate how well this method works in diagnosing coronary artery changes compared to the established methods.

Cardiac allograft vasculopathy (CAV) is a major cause of graft failure and mortality in heart transplant recipients. Unlike traditional atherosclerosis, CAV is characterized by diffuse intimal hyperplasia and concentric narrowing of coronary arteries, affecting both epicardial vessels and the microvasculature. The cause is largely unknown, although it is believed that both immunologic and non-immunologic factors could be at play. CAV is frequently asymptomatic due to denervation of the transplanted heart, underscoring the importance of routine surveillance to enable early and accurate detection. Such monitoring is essential to optimize post-transplant outcomes.

Invasive coronary angiography (ICA) is the gold standard for diagnosing CAV, while intravascular ultrasound (IVUS) can be considered as the gold standard for the assessment of intimal thickening and plaque burden. Photon-counting computed tomography (PCCT) represents a novel, non-invasive imaging modality with superior spatial resolution and tissue contrast compared to conventional CT systems.

A systematic comparison of PCCT with ICA and IVUS for detecting CAV has not yet been performed. This study aims to assess the diagnostic accuracy, clinical relevance, and cost-effectiveness of PCCT in comparison to ICA and IVUS. By evaluating the advantages and limitations of non-invasive versus invasive modalities, the study seeks to define the optimal surveillance strategy for CAV, ultimately guiding the management of heart transplant recipients and improving long-term outcomes.

Inclusion Criteria:

• Adult heart transplant recipients.
• Clinically stable and scheduled for routine ICA.
• Ability to provide informed consent

Exclusion Criteria:

• Contrast allergy
• Renal insufficiency with eGFR < 30 ml/min/m2
• Other contraindications for PCCT, ICA, or IVUS
• Acute cardiac events within 30 days prior to enrollment.

Adult heart transplant recipients scheduled for routine coronary angiography

IPD used in the results publication will be shared

January 1 2028

Reasonable request