Residual ischemia after revascularization in multivessel coronary artery disease: insights from measurement of absolute myocardial blood flow using magnetic resonance imaging compared with angiographic assessment.

BACKGROUND: Revascularization strategies for multivessel coronary artery disease include percutaneous coronary intervention and coronary artery bypass grafting. In this study, we compared the completeness of revascularization as assessed by coronary angiography and by quantitative serial perfusion imaging using cardiovascular magnetic resonance. METHODS AND RESULTS: Patients with multivessel coronary disease were recruited into a randomized trial of treatment with either coronary artery bypass grafting or percutaneous coronary intervention. Angiographic disease burden was determined by the Bypass Angioplasty Revascularization Investigation (BARI) myocardial jeopardy index. Cardiovascular magnetic resonance first-pass perfusion imaging was performed before and 5 to 6 months after revascularization. Using model-independent deconvolution, hyperemic myocardial blood flow was evaluated, and ischemic burden was quantified. Sixty-seven patients completed follow-up (33 coronary artery bypass grafting and 34 percutaneous coronary intervention). The myocardial jeopardy index was 80.7±15.2% at baseline and 6.9±11.3% after revascularization (P<0.0001), with revascularization deemed complete in 62.7% of patients. Relative to cardiovascular magnetic resonance, angiographic assessment overestimated disease burden at baseline (80.7±15.2% versus 49.9±29.2% [P<0.0001]), but underestimated it postprocedure (6.9±11.3% versus 28.1±33.4% [P<0.0001]). Fewer patients achieved complete revascularization based on functional criteria than on angiographic assessment (38.8% versus 62.7%; P=0.015). After revascularization, hyperemic myocardial blood flow was significantly higher in segments supplied by arterial bypass grafts than those supplied by venous grafts (2.04±0.82 mL/min per gram versus 1.89±0.81 mL/min per gram, respectively; P=0.04). CONCLUSIONS: Angiographic assessment may overestimate disease burden before revascularization, and underestimate residual ischemia after revascularization. Functional data demonstrate that a significant burden of ischemia remains even after angiographically defined successful revascularization.

Myocardial injury following coronary artery surgery versus angioplasty (MICASA): a randomised trial using biochemical markers and cardiac magnetic resonance imaging.

AIMS: To compare the frequency and extent of Troponin I and late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) defined injury following PCI compared with CABG in patients with multivessel and/or left main coronary artery disease (CAD), and interpret these finding in light of the new ESC/ACCF/AHA/WHF Task Force definitions for necrosis and infarction. METHODS AND RESULTS: Prospective, registered, single centre randomised controlled trial. Eighty patients with 3 vessel CAD (≥ 50% stenoses), or 2 vessel CAD including a type C lesion in the LAD, and/or left main disease were enrolled. Mean SYNTAX and EuroSCOREs were similar for both groups. Forty patients underwent PCI with drug eluting stents and 39 underwent CABG (one died prior to CABG). In the PCI group 6/38 (15.8%) patients had LGE, compared with 9/32 (28.1%) CABG patients (p = 0.25). Using the new Task Force definitions, necrosis occurred in 30/40 (75%) PCI patients and 35/35 (100%) CABG patients (p = 0.001), whilst infarction occurred in 30/40 (75%) PCI patients and 9/32 (28.1%) CABG patients (p = 0.0001). CONCLUSIONS: Periprocedural necrosis according to the Task Force definition was significantly lower in the PCI group, and universal in the CABG group. The incidence and extent of CMR defined infarction following PCI did not differ compared with CABG. This demonstrates that PCI can achieve revascularisation in complex patients without increased procedural myocardial damage.