Acute Right Coronary Artery Stent Thrombosis: A Case of Prolonged Right Ventricular Shock
Presenter
Timothy Pow, MD, Beaumont Health, Beaumont, --
Timothy Pow, MD1, Sorcha Allen, MD2, Michael Gallagher, MD3, Ivan Hanson, M.D., FSCAI4 and James A. Goldstein, M.D., FSCAI2, (1)Beaumont Health, Beaumont, --, (2)Beaumont Hospital - Royal Oak, Royal Oak, MI, (3)Beaumont Health, Royal Oak, MI, (4)Beaumont Hospital - Royal Oak, Troy, MI
Title
Acute Right Coronary Artery Stent Thrombosis: A Case of Prolonged Right Ventricular Shock
Introduction
Nearly 50% of patients with acute inferior ST-segment elevation myocardial infarction (STEMI) have concomitant right ventricular (RV) infarction which may result in predominant RV shock characterized by hypotension, clear lungs and disproportionate elevation of right heart filling pressures. Although revascularization by primary percutaneous coronary intervention typically leads to rapid improvement in RV performance and hemodynamics, recovery lags in some patients and supportive care is essential. This case describes a patient with acute right coronary artery (RCA) stent thrombosis that led to prolonged RV shock.
Clinical Case
A 67-year-old man presented to the emergency room with chest pain, electrocardiogram (ECG) showing incomplete right bundle branch block and a troponin of 0.04 ng/mL. Chest pain initially resolved but then recurred and ECG showed an inferior STEMI. Emergency angiography demonstrated the culprit RCA with an 80% proximal-to-mid stenosis. Intravascular ultrasound (IVUS) guided stenting achieved excellent result, but several hours later his chest pain recurred and repeat ECG showed marked sinus bradycardia with persistent inferior ST elevation. Repeat angiography documented acute stent thrombosis. IVUS guided aspiration thrombectomy and balloon angioplasty were performed and his chest pain initially resolved but again recurred 6 hours later, associated with hypotension and bradycardia. Emergency angiography demonstrated recurrent acute stent thrombosis at the RCA ostium. After a multidisciplinary Heart Team discussion, no further coronary intervention was performed and echocardiography showed the RV was severely dilated, the RV free wall (RVFW) dyskinetic and RV ejection fraction profoundly depressed; the left ventricle (LV) was under-filled with preserved function. An RV Impella was implanted which stabilized his aortic pressure and over 4 days the RV Impella was slowly weaned and removed. After 15 days, he was discharged from the hospital in stable condition, although echocardiography showed persistent RVFW dysfunction with LV basal inferoseptal hypokinesis. Over the next several months, repeat echocardiography showed gradual improvement in RV function. 10 months later, his RV function recovered to nearly normal and he was remaining physically active doing well.
Discussion
Studies in experimental models and in humans have established that the acutely ischemic RV is remarkably resistant to infarction and recovers rapidly following successful reperfusion. The present case illustrates prolonged ischemic RV dysfunction attributable to proximal RCA stent thrombosis compromising the main vessel and the major RV branches, with clot and stent likely delaying collateralization that ultimately restored perfusion and facilitated complete but slow recovery of RV function. This case demonstrates the importance of mechanical support in RV shock, which maintains hemodynamics thereby facilitating recovery of the resilient RV.