Impact of left ventricular function and the extent of ischemia and scar by stress myocardial perfusion imaging on prognosis and therapeutic risk reduction in diabetic patients with coronary artery disease: Results from the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial

Abstract

Background The Bypass Angioplasty Revascularization Investigation 2 Diabetes trial demonstrated similar long-term clinical effectiveness of revascularization (REV) and intensive medical (MED) therapy. Comparisons of post-intervention ischemic burden have not been explored but are relevant to treatment decisions. This study examined differences in 1-year stress myocardial perfusion SPECT (MPS) abnormalities by randomized treatment. Methods MPS was performed in 1,505 patients at 1-year following randomization. MPS images were analyzed (masked to treatment) by a Nuclear Core Laboratory using a quantitative percent (%) of total, ischemic, and scarred myocardium. Cox proportional hazards models were used to estimate the relationship between MPS variables and trial endpoints. Results At 1-year, nearly all REV patients underwent the assigned procedure; while 16% of those randomized to MED received coronary REV. Patients randomized to REV exhibited fewer stress perfusion abnormalities than MED patients (P < .001). CABG patients had more frequent ischemic and scarred myocardium encumbering ≥5% of the myocardium when compared to those receiving PCI. Patients randomized to MED had more extensive ischemia and the median % of the myocardium with perfusion abnormalities was lower following REV (3% vs 9%, P = .01). A total of 59% of REV patients had no inducible ischemia at 1-year compared to 49% of MED patients (P < .001). Within the CABG stratum, those randomized to MED had the greatest rate of ischemic (P = .032) and scarred (P = .017) perfusion abnormalities. At 1-year, more extensive and severe stress myocardial perfusion abnormalities were associated with higher 5-year rates of death and a combined endpoint of cardiac death or myocardial infarction (MI) rates (11.3%, 8.1%, 6.8%, for ≥10%, 5%-9.9%, and 1-4.9% abnormal myocardium at stress, respectively, P < .001). In adjusted models, selected MPS variables were significantly associated with an increased hazard of cardiac death or MI (hazard ratio = 1.11 per 5% increase in abnormal myocardium at stress, P = .004). Conclusions Patient management strategies that focus on ischemia resolution can be useful to guide the efficacy of near-term therapeutic approaches. A 1-year post-therapeutic intervention myocardial perfusion scan provides important information regarding prognosis in stable CAD patients with diabetes. (J Nucl Cardiol 2012;19:658–69.)

A multifunctional CT technology: Reality or illusion for patient risk assessment?

“…There is robust evidence that myocardial burden size of functional myocardial ischemia and ischemia-related left ventricular dysfunction both of which are assessed simultaneously by stress electrocardiogram-gated myocardial single-photon emission computed tomography have mid-to long-term cardiac events. [15][16][17][18] Together with the issue previously mentioned, two types of non-negligible false positive features in the assessment of anatomical narrowing by coronary CT angiography and functional ischemia by stress myocardial CT perfusion imaging have to be furthermore overcome for the improvement in the clinical values of the presented findings so that their complementary assessment using a contrast medium and a stress agent could be more effective in the clinical setting.…”

Noninvasive assessment myocardial viability: Current status and future directions

“…They found that the reduction of ischemia by revascularization and extent of scar as defined on SPECT at 1 year to be powerful predictors of patient outcome. 164 …”

Refining risk in diabetes and CAD with SPECT MPI: New insights and future challenges

“…[18][19][20] The DIAD study reported that 22% of asymptomatic diabetic patients had myocardial ischemia on adenosine Tc-99 m SPECT MPI, 18 and subsequent COURAGE, INSPIRE, and BARI-2D trials confirmed the powerful incremental risk assessment with SPECT MPI as well as favorable effects of optimal medical therapy in patients with CAD and/or DM. [21][22][23] In the current issue of the Journal of Nuclear Cardiology, Morales et al report a large retrospective analysis of 17,499 patients undergoing SPECT MPI at a single tertiary center from 1996 to 2006. 24 The study explores the interaction of risks of subsequent hard coronary events identified by diabetes mellitus, history of CAD, and the presence of greater than mild stress perfusion defect (SSS C 4) 24 equivalent to a 6% total stress LV perfusion defect score.…”