Myocardial Infarction With Nonobstructive Coronary Arteries With Coronary Microvascular Dysfunction Associated With...

Myocardial infarction with nonobstructive coronary arteries (MINOCA) accounts for a meaningful proportion of acute myocardial infarction presentations and encompasses heterogeneous mechanisms. Coronary microvascular dysfunction (CMD) is a major cause of MINOCA and can be invasively characterized using coronary physiology indices, including the index of microvascular resistance (IMR) and coronary flow reserve (CFR). Systemic sclerosis (SSc) is associated with small-vessel vasculopathy and may predispose individuals to CMD. However, MINOCA attributable to SSc-related CMD confirmed by invasive coronary function testing and cardiac magnetic resonance (CMR) is not widely reported.

A 76-year-old woman with SSc and interstitial pneumonia presented with persistent chest pain. Electrocardiography revealed new T-wave inversions in leads V1-V4, and echocardiography demonstrated mid-anterior left ventricular asynergy. Troponin T was elevated (0.206 ng/mL). Emergency coronary angiography showed no obstructive epicardial stenosis, but left ventriculography confirmed regional wall-motion abnormality. CMR demonstrated base-to-mid anteroseptal dysfunction with increased native T1, T2, and extracellular volume fraction, supporting MINOCA. Transient systemic inflammation was observed (peak C-reactive protein 14.69 mg/dL; white blood cell count 24,600/μL) without evidence of infection and it resolved spontaneously. Six weeks later, acetylcholine provocation testing was negative for epicardial spasm, but invasive physiological assessment identified CMD (IMR 30.5; CFR 1.7). The patient was treated with a calcium-channel blocker and nicorandil. At 3-month follow-up, symptoms, electrocardiographic changes, and CMR abnormalities normalized, which indicated a reverse of the ischemic injury. No recurrence occurred during 1 year of follow-up.

SSc-associated MINOCA, possibly driven by CMD, was diagnosed by comprehensive invasive coronary function testing and CMR. Serial CMR may help to document reversibility of microvascular ischemic injury and guide vasodilator therapy and follow-up.