CRT 2017 Interventional Challenging Case Anterior ST- Elevation Myocardial Infarction Resulting From Acute Occlusion of Left Internal Mammary Artery Graft With Chronic Total Occlusion of Left Anterior Descending Artery Ibrahim Kassas, MD, Nikolaos Kakouros, MD, PhD University of Massachusetts Medical School Worcester, MA No Disclosures

Clinical Presentation A 72-year-old man with diabetes mellitus, hypertension, dyslipidemia, underwent coronary artery bypass grafting (CABG) surgery 3 years ago with left internal mammary artery graft (LIMA) to distal left anterior descending artery (LAD) and saphenous venous grafts (SVGs) to the obtuse marginal (OM) and right posterior descending (rPDA) arteries. He had severe ischemic cardiomyopathy (LVEF 30%), an implantable defibrillator and prior cerebrovascular event with left sided hemiparesis. He presented with acute onset substernal chest pain associated with significant nausea and vomiting . Physical examination revealed borderline hypotension and euvolemia. ECG revealed sinus rhythm at 85 bpm and ST-segment elevation in the anteriorolateral leads. He was taken emergently to the cardiac catheterization lab.

EKG

Cardiac Catheterization: Diagnostic After initiation of intravenous UFH, patient was taken to the cardiac cath lab for coronary angiogram Left radial artery was not accessible due to hemiplegic contracture so right femoral arterial access was obtained. Coronary angiography revealed occlusion of the ostial LAD with heavy calcification. Left circumflex artery was severely diseased and the proximal right coronary artery was totally occluded.

Cardiac Catheterization: Diagnostic Both SVGs were patent. The patient remained hemodynamically tenuous with persistent chest pain and vomiting; so intravenous infusion of tirofiban was started. The LIMA had TIMI 1 flow with occlusion of the distal third. Intra-Aortic Balloon Pump (IABP) was inserted via the left femoral artery.

Attempting to treat ostial LAD calcified occlusion Initial attempts were made to the ostial LAD using an EBU catheter, Prowater, and FielderXT guidewires with support from a FineCross catheter. The LAD had characteristics of a Chronic Total Occlusion (CTO), so attempts were abandoned and attention turned to the LIMA.

Unexpected Outcome A Prowater was advanced to the distal LIMA via an IMA catheter with some restoration of flow and appearances consistent with dissection. A Runthrough wire was manipulated through the anastomosis to the distal LAD with FineCross support. Serial drug- eluting stents were deployed from the anastomosis covering the entire length of LIMA graft (180 mm) due to proximal dissection propagation.

Final Outcomes ECG and hemodynamics improved after re-establishing blood flow. Echocardiogram showed unchanged LVEF of 30% with no evidence of mechanical complications. The patient was started on optimal medical therapy and eventually discharged to rehabilitation center.

Discussion I IIa IIb III A Primary PCI should be performed in patients with STEMI and ischemic symptoms of less than 12 hours’ duration. Challenges in the Cath lab: Which vessel to revascularize? Ostial LAD Chronic Total Occlusion vs. LIMA occlusion possibly due to dissection. Mechanical Circulatory support upfront versus provisional. Limited surgical back-up options with exposed chest wall wound and prior CABG Intractable vomiting during entire procedure precluding oral administration of anti-platelet therapy and needing intravenous infusion of IIB/IIIA inhibitor. References: O’Gara, et al. J Am Coll Cardiol. 2013;61(4):e78-e140 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction:

Conclusions LIMA graft dissection lead to diminished blood flow to the LAD territory resulting in the clinical presentation with anterior STEMI. Attempting to intervene worsened the dissection and left the interventional team with limited options to safely manage this complex case. We describe a challenging case of ACS that demonstrates the importance of early recognition of dissection in coronary arteries and grafts as well as the early use of mechanical circulatory support to maintain hemodynamic stability during such complicated interventions