Severity of Remodeling, Myocardial Viability, and Survival in Ischemic LV Dysfunction After Surgical Revascularization

Abstract

Objectives The objectives of this study were to test the hypothesis that end-systolic volume (ESV), as a marker of severity of left ventricular (LV) remodeling, influences the relationship between myocardial viability and survival in patients with coronary artery disease and LV systolic dysfunction. Background Retrospective studies of ischemic LV dysfunction suggest that severity of LV remodeling determines whether myocardial viability predicts improved survival with surgical (CABG) compared to medical (MED) therapy, with CABG only benefitting patients with viable myocardium who have smaller ESV. However, this has not been tested prospectively. Methods Interactions of ESV index (ESVI), myocardial viability and treatment with respect to survival were assessed in patients in the prospective randomized STICH trial of CABG vs MED who underwent viability assessment (n=601, age 61±9 years, ejection fraction ≤35%), median follow-up 5.1 years. Median ESVI was 84 ml/m2. Viability was assessed by SPECT or dobutamine echocardiography using prespecified criteria. Results Mortality was highest among patients with larger ESVI and non-viability (P<0.001), but no interaction was observed between ESVI, viability status, and treatment assignment (P=0.491). Specifically, the effect of CABG versus MED in patients with viable myocardium and ESVI ≤84 ml/m2 (HR 0.85, 95% CI 0.56,1.29) was no different than in patients with viability and ESVI >84 ml/m2 (HR 0.87, 95% CI 0.57,1.31). Other ESVI thresholds yielded similar results, including ESVI ≤60 ml/m2 (HR 0.87, 95% CI 0.44,1.74). ESVI and viability assessed as continuous rather than dichotomous variables yielded similar results (P=0.562). Conclusions Among patients with ischemic cardiomyopathy, those with greater LVESVI and no substantial viability have worse prognosis. However, the effect of CABG relative to MED is not differentially influenced by the combination of these two factors. Lower ESVI does not identify patients in whom myocardial viability predicts better outcome with CABG relative to MED.

2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure

“…CMR may also be used for the assessment of myocardial ischaemia and viability in patients with HF and CAD (considered suitable for coronary revascularization). However, limited evidence from RCTs has failed to show that viability assessed by CMR or other means identified patients who obtained clinical benefit from revascularization …”

2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure

“…Ograniczona liczba dowodów z RCT nie pozwoliła jednak na udokumentowanie klinicznych korzyści z rewaskularyzacji u pacjentów, u których żywotność mięśnia sercowego została oceniona w CMR [105][106][107].…”

Myocardial Viability Assessment is Still Alive and an Important Element in Predicting Prognosis and Providing Optimal Management for Ischemic Heart Failure

“…Bo now et al reported that absence of viability with LV remodeling (end-systolic volume index > 84 ml/m 2 ) predicts the highest mortality regardless of treatment. However, combination of viability and LV remodeling did not influence the effect of CABG relative to medical therapy in STICH cohort [30].…”