Outcomes of coronary artery bypass grafting based on myocardial perfusion imaging

Introduction
Coronary artery disease (CAD) is the foremost single cause of mortality and loss of disability-adjusted life years globally and a large percentage of this burden is found in low and middle income countries, with the treatment strategies based on revascularisation, based on studies that have shown that on revascularisation of viable myocardium there is an improvement of function over a period of time.

Aim
To evaluate the utilization of myocardial perfusion imaging (MPI) for identifying viable myocardium and assessing the improvement.

Material and methods
This prospective observational study was conducted in patients having CAD planned for coronary artery bypass grafting. The patients were evaluated using 2D ECHO and MPI preoperatively and postoperatively after 1 year.

Results
Mean ejection fraction preoperatively was 40.6 ±9.72% and postoperatively it improved to 41.32 ±10.64% and ejection fraction was calculated using MPI and an average improvement from 35.98 ±12.72% to 45.51 ±12.61% (p  0.0001). Summed rest score was calculated and an improvement was noted from 24.28 ±8.47 to 18.02 ±8.75 (p  0.0001). Total perfusion deficit was calculated and was found to have reduced from 32.44 ±11.98 to 25.61 ±12.23 (p  0.0001).

Conclusions
MPI was able to accurately assess the improvement, which correlated not only with the 2D echocardiography data but also with the clinical wellbeing of the patients. Being a non-invasive, quick procedure, it should be added to the arsenal of the cardiac surgeon for evaluation of patients with diffuse diseases, low ejection fractions, patients who might generally be considered inoperable.