16 Safety and feasibility of adenosine stress cardiac MRI in heart transplant recipients

<h3>Introduction</h3> Stress perfusion cardiac magnetic resonance (CMR) is recommended in international guidelines in class I in patients with known or suspected CAD. Patients undergoing cardiac transplantation (OHT) are at risk of developing cardiac allograft vasculopathy (CAV). Adenosine is relatively contraindicated after transplantation because of a presumed risk of atrioventricular block in denervated hearts. We sought to evaluate the safety and feasibility of adenosine stress CMR in patients with OHT and suspected CAV. <h3>Materials and Methods</h3> In an outpatient cohort study, we measured the incidence of adverse effects of adenosine stress CMR in consecutive OHT recipients undergoing quantitative stress perfusion CMR for suspected CAV. We additionally stratified patients based on presence of significant CAV (grades 2–3 versus 0–1) on either invasive or computed tomography coronary angiography to evaluate potential CMR biomarkers of significant coronary disease in this population. <h3>Results</h3> We identified 50 adenosine stress CMR studies performed in 45 individual patients at a median of 19 years after transplantation (IQR 4.7–24.4); 9% of studies were conducted within the first year post-transplantation. No life-threatening adverse events, brief or prolonged atrioventricular block or other arrythmias occurred after adenosine infusion. Significant myocardial ischemia (≥ 1.5 segments) was reported in 17% of patients. When stratified by CAV severity, stress MBF index, but not inducible ischemia on visual inspection, was found to significantly differentiate patients with severe CAV from those without significant coronary disease (ANOVA p = 0.028). <h3>Conclusion</h3> Adenosine stress perfusion CMR is safe and feasible in OHT recipients. Quantitative measurement of stress MBF index may represent a promising marker of coronary disease with incremental value over qualitative assessment of ischemia, and should be evaluated in future studies. <h3>Acknowledgements</h3> None