Extracellular Volume Estimation in the Assessment of Myocardial Viability in Ischaemic Cardiomyopathy

OBJECTIVES: To determine the role of extracellular volume estimation (ECV) along with Late gadolinium enhanced (LGE) MRI in assessing viability in patients with chronic ischemic cardiomyopathy. BACKGROUND: Imaging techniques form myocardial viability estimation have shown varying results and outcomes in patients with chronic ischemic cardiomyopathy. In the current form viability estimation is being questioned as a single important prognostic prerevascularisation variable. Hence there is a need to explore new and a robust technique to achieve the above goal. METHODS: 22 consecutive patients diagnosed with chronic ischemic cardiomyopathy which were considered for bypass grafting and had angiographic proven triple vessel disease and or left main stenosis with reduced ejection fraction of 50% were labeled as nonviable. Six month primary outcome measure was improved ejection fraction following revascularisation. RESULTS: Sensitivity and specificities for detection of nonviable segments on LGE and ECV-LGE were 69%, 100%and 96%, 100% with AUC’s being 0.84 and 0.98 respectively. Patients with CV score of >8 showed positive primary outcome of improved ejection fraction of 42.8% while those with CV score<8 showed a negative primary outcome. Group II patients with viable myocardium with significant fibrous tissue i.e. ECV of 28-49% showed partially improved function. CONCLUSION: Estimation of ECV-LGE method had 96% sensitivity in the detection of nonviable segments and also showed a positive primary outcome with improved ejection fraction at six months with viability being a Bayesian variable which depended upon the quantity of fibrous tissue in the viable myocardium.