Acute Chest Pain After PCI
A 67-year-old man with hypertension, hyperlipidemia, and a remote history of pulmonary embolism (PE) presented with sudden onset non-pleuritic substernal chest pain while walking around his home. He also noted dyspnea and lightheadedness followed by syncope. Emergency medical services responded and found the patient to have fluid-responsive hypotension (blood pressure of 64/48 improved to 124/57 mmHg with 1L normal saline, initial recorded heart rate of 54 bpm, SpO2 of 99% placed immediately on 2L nasal cannula). He was taken to a nearby hospital.
An electrocardiogram (ECG) on arrival revealed inferior ST-segment depressions. The initial troponin I was elevated (8.9 ng/mL), but laboratory results were otherwise unremarkable. Complete transthoracic echocardiogram (TTE) showed normal right ventricular (RV) size and function and a hyperdynamic left ventricle with an ejection fraction of 70-75%. High-risk non-ST-segment elevation myocardial infarction (MI) was diagnosed, and urgent left heart catheterization revealed an 80% right coronary artery lesion (Thrombolysis in Myocardial Infarction [TIMI] 3 flow, no thrombus) successfully treated with a drug-eluting stent (0% residual lesion, no dissection, TIMI 3 flow). In the hospital, the patient experienced complete resolution of symptoms. Troponin I peaked at 13.6 ng/mL. Upon discharge on hospital day 2, he walked to the nearby Veterans Administration hospital to pick up his prescriptions, and identical symptoms recurred. In the emergency department at that hospital, his vital signs were afebrile, with a heart rate of 67 bpm, blood pressure of 131/62 mmHg, respiratory rate of 20, and SpO2 of 98% on room air. An ECG was done. Troponin I was elevated to 2.7 ng/mL and N-terminal pro-B-type natriuretic peptide was 1004 pg/mL. Renal function was normal. Troponin I down-trended to 2.3 ng/mL 3 hours later.
What is the next best step in management?