Emergency Medicine News:
Dr. Bruen is a fellow in critical care medicine and emergency cardiology at Hennepin County Medical Center in Minneapolis. He has special interest in stabilization, resuscitation, hemodynamic evaluation, and emergency cardiovascular care. Visit his website, http://resusreview.com, follow him @resusreview, and read his past columns at http://bit.ly/SponCirc.
She watched the Camry coming straight at her, obeying the laws that Newton had laid out. Her husband, daughter, and the weatherman had told her not to go out, but she needed milk, and the store was only three blocks away. Her plan was simple: to the store, milk, home. That might have worked if not for the Camry that became a hockey puck on the ice.
The next couple of hours were a blur, but proceeded as readers would expect: 911, paramedics, backboard, cervical collar, ambulance, IV, medicine, stabilization bay, ultrasound, x-rays, more medicine, scanner, hospital bed. She had suffered an acetabular fracture and femoral head fracture. On hospital day 5, her physicians thought she was safe for surgery, and she underwent a successful ORIF of the posterior acetabulum and total hip arthroplasty. But then she developed chest pain, diaphoresis, and nausea on post-op day 1. Her heart rate slowed to 30 bpm, and she was hypotensive: 90 mm Hg systolic. She responded to a 1000 mL bolus of 0.9% saline and atropine. A 12-lead ECG was obtained. (Figure.)
The ECG shows Q-waves in the inferior leads with ST-segment elevation. The R:S ratio is >1 in the right precordial leads, suggestive of a true posterior injury. Reciprocal changes are noted in leads I and aVL. There is a first-degree atrioventricular block. These changes are diagnostic of an inferior ST-elevation myocardial infarction. The bradycardia and hypotension that the patient experienced is suggestive of Bezold-Jarisch reflex, a common epiphenomenon with inferior infarctions.
A STEMI is a clear indication for emergent revascularization, but several factors complicated the medical decision-making. She was at a very high risk for bleeding given her recent surgery. Dual antiplatelet therapy and anticoagulation would exacerbate the bleeding risk, which would persist not only during the angiography but afterward if any intervention was performed. Nevertheless, given the risk-benefits, she was treated with an aspirin and taken to the cardiac catheterization lab to define the coronary anatomy and identify the culprit lesion.
She was found to have diffuse disease in the LAD and circumflex coronary arteries but without high-grade obstructive disease. Patent left-to-right collaterals were seen, but there was a 100% occlusion of the ostium of the RCA. Balloon angioplasty reduced this to 30 percent, which reestablished flow. Unfortunately, a thrombectomy catheter could not cross the lesion. No stenting was performed. Any stent, bare metal or drug-eluting, would have required dual antiplatelet therapy, which would have placed the patient at high risk for bleeding. The distal RCA was small in caliber, indicating chronic disease. Placing a stent would also have required additional contrast dye, which would have placed the patient at risk for contrast-induced nephropathy. A temporary pacemaker was placed given her episode of bradycardia.
She remained hemodynamically stable, and no decrease of renal function was seen. Troponin I peaked at 17 ng/mL, and she had no further episodes of chest pain. She recovered completely from her hip surgery over the following weeks. A month after her STEMI, she underwent PCI to the RCA ostia and mid LAD without any bleeding complications.
Find a complete discussion of this case, two videos, and additional images on June 5 in the EMN iPad app and on June 12 in the Spontaneous Circulation blog on www.EM-News.com, where the EMN app can also be downloaded for free.
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