Improved aorto-ventricular matching in ischemic dilated cardiomyopathy patients after surgical ventricular restoration

SCOPE: This paper contains (i) derivation of the aorto-ventricular matching (AVM) index in terms of the ratio of aortic elastance and LV end-systolic elastance, E(aorta)/E(es); (ii) procedure for determination of this index, by means of non-invasive measurements of auscultatory pressures, time-variation of blood volume ejected into the aorta, stroke volume and ejection fraction; (iii) results of improved AVM index evaluation in ischemic dilated cardiomyopathy (IDCM) patients following surgical ventricular restoration (SVR), as a result of reduced end-diastolic and end-systolic LV volumes and increased LV E(es). METHODOLOGY: Among the ten recruited IDCM patients, four of them underwent surgical ventricular restoration (SVR) and coronary artery bypass graft (CABG), while six of them underwent CABG alone. All patients were studied by echocardiography pre- and 4 months post-operatively; LV volumes were determined by echo Doppler. LV end-systolic elastance E(es) was determined from a derived expression, by employing blood pressure, stroke volume, ejection fraction, pre-ejection and systolic periods, and estimated normalized ventricular elastance at end-diastole, based on single-beat measurements. Aortic elastance E(aorta) was determined by means of our modified single-beat method for determining aortic pressure profile. RESULTS: In the CABG plus SVR group, the AVM index E(aorta)/E(es) was reduced by 35% from 0.93±0.32 to 0.60±0.33, consistent with improved aorto-ventricular matching. However, in the CABG alone group, the AVM index E(aorta)/E(es) decreased only 11% from 1.02±0.24 to 0.91±0.29. CONCLUSION: There is shown to be increased value of LV E(es) and a more favorable decreased value of AVM index in those IDCM patients who underwent SVR.