Coronary Artery Vasospasm: A Under-recognized Phenomenon in Orthotopic Heart Transplant

Introduction Cardiac allograft vasculopathy (CAV) is known as the primary cause of death in the first year after orthotopic heart transplant (OHT). Coronary artery spasm (CAS) in OHT is a rare and under-recognized phenomenon in patients undergoing surveillance. The mechanism of coronary vasospasm in OHT remain largely unknown. The presentation can vary from an incidental finding to severe episodes of symptomatic ventricular arrhythmias, high-degree atrioventricular block, syncope, cardiac arrest, or even myocardial infarction in cases of prolonged ischemia. Case Presentation 65 yo female with history of chronic kidney disease, diabetes mellitus type 2, hypertension, hyperlipidemia, and orthotopic heart transplantation with CMV mismatch in 2016 secondary to apical hypertrophic cardiomyopathy. Prior coronary angiography (CA) done at our institution had shown no evidence of vasculopathy. During one of her follow-up visits in the Clinic, she complained of increasing dyspnea on exertion, prompting urgent referral for CA, as per our surveillance protocols. Prior to the procedure, echocardiography was performed which revealed normal graft function and no valvular abnormalities. She underwent CA which showed a proximal significant diffuse luminal narrowing of the right coronary artery (RCA) (Image 1) and normal left coronary artery anatomy (Image 2). We proceed to repeat CA with intracoronary administration of nitroglycerin (ICN) and measurement of fractional flow reserve (FFR) of RCA (Image 3, 4). Angiography revealed near resolution of the RCA lesion, ultimately suggesting that transient vasospasm had been responsible for the previous angiographic appearance (Image 1). Summary CAS can present in patients with or without vasculopathy. It can produce luminal narrowing and can be difficult to distinguish angiographically from CAV. Misdiagnosis of this entity has led to the incorrect diagnosis of CAV and subsequent unnecessary stenting. ICN use can improve angiographic visualization, and prevent the adverse effects of coronary spasm. In conclusion, CAS is a rare and potential complication post OHT. It is a difficult entity to prognosticate due to scarcity of clinical evidence, as prevalence ranges from 4.9% to 12.1%. Some authors hypothesize that CAS in OHT carries a poor prognosis as it is often an early manifestation of CAV. However, this remains largely hypothetical and further studies are needed to better understand this disease.