Coronary Revascularization Based on CMR Viability Study Vs Direct Revascularization in Ischemic Cardiomyopathy Patients

The study aiming to demonstrate the baseline characteristics and outcomes of patients undergoing revascularization by PCI vs those kept only on medical treatment, based on CMR viability assessment.

Cardiac magnetic resonance (CMR) has an ever-increasing role in the assessment and management of patients with coronary artery disease (CAD). Advantages of CMR include the lack of ionizing radiation and its flexibility, high spatial resolution, and three-dimensional capabilities that enable imaging in any desired plane.

In the evaluation of patients with ischemic cardiomyopathy, CMR is primarily used in the setting of chronic CAD for the evaluation of myocardial ischemia and viability.

Left ventricular systolic dysfunction, resulting from coronary artery disease is reversible with revascularization in cases of hibernation and stunned myocardium. Revascularization is dependent not only on the presence but also the extent of viability, and a viable myocardium is necessary for functional recovery.

In a CMR study, in areas with dysfunctional myocardium as detected in cine sequences, the end diastolic wall thinning \>5.5 mm, the extent of subendocardial fibrosis together with response to low dose dobutamine were shown to predict functional recovery.

However, in the famous viability sub study of the STICH (Surgical Treatment for Ischemic Heart Failure) trial, there was a significant association between myocardial viability and outcome by univariate analysis, but not on multivariable analysis. Thereby, the value of CMR in this regards is still debatable.

So, according to the recent state of art paper from the American Heart Association, data is still limited regarding CMR use to guide revascularization strategies or predict outcomes in patients with severe LV dysfunction. The statement recommended that future trials should continue to address the clinical impact of specific modality-based strategies or multimodality strategies in guiding treatment in terms of patient outcomes.

On the other hand, appropriately guided coronary revascularization may go beyond providing recovery of myocardial systolic contractility by improving patient's functional class and heart failure symptoms, enhancing diastolic relaxation, reducing the burden of rhythm abnormalities, or decreasing the burden of polypharmacy, thereby reducing the risk of drug toxicity and improving quality of life. These additional benefits need also to be explored in clinical trials.

Eligibility Criteria:
Inclusion Criteria:

1. Patients \>18 years of age, with LVEF\<40%.
2. Patients presenting for viability assessment to Assiut university Heart Hospital, starting from October 2020 till September 2021, will be retrospectively recruited.
3. Patients with a coronary angiography that is amenable for revascularization. The decision and type of revascularization will be determined by the treating physicians.

Exclusion Criteria:

1. Classic CMR and gadolinium-based dye contraindications including non-MRI compatible implants/foreign bodies (e.g. non-MRI compatible pacemaker, large pieces of shrapnel) and patients with eGFR\<30 ml/min/1.73 m2.
2. Patients with non-ischemic cardiomyopathy confirmed by both CMR and coronary angiography.