Presentation
Case Findings: A 50-year old male with family history significant for premature CAD presents with chest pain which started 3 hours ago. Blood pressure 150/90 mm Hg, HR 60/min. EKG in the emergency department is shown (see image below). Successful intervention of the culprit coronary artery is performed with one drug eluting stent. He is started on aspirin, ticagrelor, atorvastatin and metoprolol. Next morning he is found to be hypotensive to SBP 90s. Hemoglobin, creatinine and electrolytes are normal. Right groin access site is without any hematoma. A stat bedside echocardiogram reveals ejection fraction 55%, no significant valvular dysfunction, mild right ventricular dilation. A diagnosis of right ventricular failure is made and intravenous hydration is initiated.
What is the culprit vessel segment?
59% A. Distal right coronary artery
28% B. Distal left circumflex
80% C. Proximal left anterior descending artery
160% D. Proximal right coronary artery
Correct Answer:
D. The EKG shows significant ST elevation in inferior leads (II,III,aVF) with reciprocal changes (ST depressions with T wave inversions in anterior leads). This is suggestive of right coronary artery or dominant left circumflex artery acute thrombosis. Right ventricular failure arises when RV branch is compromised during stent placement. This happens due to displacement of soft plaque specifically during acute coronary syndromes. Since RV branch divides RCA into proximal and mid segments, the culprit lesion has to be in either the proximal or mid RCA. Distal RCA is incorrect because it would not justify the development of RV failure. Left circumflex artery and left anterior descending arteries are also incorrect because RV branch does not arise from these arteries. The question highlights basic knowledge of the coronary segments and major branches.