The cardiac catheterization procedure will be done according to standard protocol as part of the standard clinical care. This has become the standard of care in any patient in which it feasible and is performed with low risk.

Arterial elastance (Ea) is measured by the pressure volume (PV) loop catheter in the left ventricle. The PV loop catheter measures pressure and volume simultaneously during the entire cardiac cycle. Arterial elastance is a measure of ventricular afterload and will be calculated using previously described formula;

Ea (arterial elastance): Ea = Pend systole/ SV

(where P, is pressure at end systole, and SV is stroke volume).

Elastance will be reported as a continuous variable in mmHg/mL with a higher number indicating an increase in elastance and a negative number indicating a decrease in elastance. Change in elastance before and after stent placement will be compared using paired T test.

The end systolic pressure volume relationship (ESPVR) summarizes ventricular systolic function and is measured as a slope of End systolic ventricular elastance (Ees) and volume-axis intercept Vo such that ESP = Ees (ESV-Vo) (ESP = end-systolic pressure, ESV = end-systolic volume, Vo represents the unstressed volume, which is the volume required to fill the ventricle before pressure rises). Shifts of the ESPVR occur with changes in ventricular contractility such that increases in contractility are associated with upward/leftward shifts of the ESPVR. ESPVR is obtained by analysing the data and PV loops obtained by PV loop catheter in the left ventricle before and after intervention. It will be depicted as a continuous variable in mmHg/ml as well as graphically as a slope. Changes before and after intervention will be compared as shifts in ESPVR.