Left Ventricular Diastolic Function Similar After On-Pump and Off-Pump CABG

Left ventricular (LV) diastolic function improvement after coronary artery bypass graft (CABG) is similar regardless of whether the patient undergoes surgery on-pump or off-pump, according to a report in the March 1st issue of The American Journal of Cardiology.

Dr. Mario J. Garcia and colleagues from Cleveland Clinic Foundation, Cleveland, Ohio sought to determine the effect of surgical revascularization on LV diastolic function and to determine whether it differed in 16 patients undergoing standard on-pump CABG and 14 patients undergoing off-pump CABG.

Patients operated on-pump experienced significant increases in various measures of diastolic function, the authors report, including mitral atrial wave velocity, low propagation velocity, and left atrial contractility without significant changes in LV operating stiffness.

Patients operated off-pump also showed significant increases in these variables, as well as increases in early diastolic intraventricular pressure gradients.

The improvements in LV filling and relaxation were somewhat greater in the patients operated on-pump, the investigators report, noting that “these observed differences could be related to the use of norepinephrine in the CABG off-pump patients.”

Basic hemodynamics did not change otherwise in the two groups, the researchers note, and the groups had similar numbers of bypass grafts and postoperative creatine kinase-MB subfraction levels.

“We have shown that there is an immediate improvement in diastolic function after operation in patients who underwent CABG,” the authors conclude, “independent of the use of extracorporeal circulation.”

“Diastolic function improved in both groups,” the researchers add, “but indexes of early diastolic filling and myocardial relaxation improved more in patients who underwent on-pump than off-pump CABG.”