CASE 8 STEMI Intervention and Stent Thrombosis

Lawrence W. Gimple, MD, FACC, FSCAI

Case presentation

A 45-year-old man presented to the emergency department with severe substernal chest pain of 2.5 hours duration. In the emergency department, the initial ECG showed sinus rhythm at a rate of 71 bpm with ST segment elevation in leads II, III, aVF, and V4 to V6. A “STEMI-Alert” was initiated to facilitate rapid coordination of reperfusion therapy.

The patient had a past history of atypical chest pain, hyperlipidemia, and gout. He worked as a self-employed artist; he denied tobacco abuse but smoked marijuana daily. He took no prescription medications. His physical examination was unremarkable, and laboratory studies found an initial troponin of 0.03 ng/mL, normal blood count and renal function, and marked lipid abnormalities (HDL 48 and LDL 213 mg/dL). Initial treatment began in the emergency room with aspirin (325 mg), clopidogrel (600 mg), and unfractionated heparin intravenous bolus (60 U/kg). He was referred for an emergency catheterization.

Cardiac catheterization

An ACT was measured and additional heparin administered to achieve an ACT between 250 and 300 seconds. Based on the ECG, the right coronary artery was the suspected infarct artery and was engaged first using a 6 French JR4 guiding catheter. Right coronary angiography revealed occlusion of the distal vessel, with retained contrast at the occlusion site (Figure 8-1 and Video 8-1). Eptifibatide was administered (two boluses, each of 180 mcg per kg, and an infusion of 2.0 mcg/kg per minute for 14 hours). The operator crossed the occlusion with a 0.014 inch floppy-tipped guidewire and TIMI-3 flow was restored after balloon dilatation with a 2.5 mm diameter by 15 mm long, compliant balloon. Following this, a 3.0 mm diameter by 23 mm long bare-metal stent was selected based on visual determination of the proximal and distal reference segments (Figure 8-2 and Video 8-2). A bare-metal stent was selected due to uncertainty about future medication compliance. The stent was positioned across the narrowed arterial segment and deployed at 14 atmospheres of pressure. The operator achieved a satisfactory angiographic result (Figure 8-3 and Video 8-3); intravascular ultrasound was not used.

FIGURE 8-1 Initial angiogram of the right coronary artery in the LAO cranial view showing the acute occlusion of the distal right coronary.

FIGURE 8-2 Placement of a bare-metal stent in the right coronary artery in the LAO cranial view following balloon angioplasty.

FIGURE 8-3 Final image of the right coronary artery in the LAO cranial view showing an excellent angiographic result in the distal right coronary artery. The more distal lesion was not significant in additional views.

Following stenting of the right coronary artery, the left coronary, imaged in standard views, showed minimal coronary atherosclerosis. A biplane left ventriculogram showed inferior and inferolateral hypokinesis with a preserved global ejection fraction estimated at 55%. The patient remained hemodynamically stable throughout the procedure. The vascular access sheath was removed with manual compression after 4 hours when the ACT was measured at less than 180 secs but while the eptifibatide infusion was continuing. He was treated during “off hours” with a door-to-balloon time of 64 minutes.

Postprocedural course

The patient recovered uneventfully, with his troponin level rising to 69 ng/mL. He was enrolled in cardiac rehabilitation and counseled regarding lifestyle modification, diet, weight loss, physical activity, and smoking (tobacco and marijuana) avoidance. He was discharged on the third hospital day and prescribed full-dose aspirin, clopidogrel, simvastatin, ezetimibe, lisinopril, and metoprolol. The importance of medical compliance, especially with aspirin and clopidogrel, was emphasized to the patient.

Three months later, the patient again presented to the emergency department after suffering chest pains for 5 hours. The initial ECG demonstrated 3 to 4 mm ST elevations in leads 2, 3, and aVF with Q waves in those leads. The patient had not kept his previous medical follow-up appointments and admitted to stopping all of his medications after running out of prescriptions 3 weeks prior to the current presentation. Again, he was promptly treated in the emergency department with aspirin (325 mg), clopidogrel (600 mg), and unfractionated heparin (60 U/kg) and brought emergently to the cardiac catheterization laboratory. Right coronary angiography confirmed the suspected occlusion at the site of the previously-placed bare-metal stent (Figure 8-4

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