Left Ventricular Systolic Unloading and Augmentation of Intracoronary Pressure and Doppler Flow During Enhanced External Counterpulsation

Abstract

Background-Enhanced external counterpulsation (EECP) is a noninvasive, pneumatic technique that provides beneficial effects for patients with chronic, symptomatic angina pectoris. However, the physiological effects of EECP have not been studied directly. We examined intracoronary and left ventricular hemodynamics in the cardiac catheterization laboratory during EECP. Methods and Results-Ten patients referred for diagnostic evaluation underwent left heart catheterization and coronary angiography from the radial artery. At baseline and then during EECP, central aortic pressure, intracoronary pressure, and intracoronary Doppler flow velocity were measured using a coronary catheter, a sensor-tipped high-fidelity pressure guidewire, and a Doppler flow guidewire, respectively. Similar to changes in aortic pressure, EECP resulted in a dramatic increase in diastolic (71Ϯ10 mm Hg at baseline to 137Ϯ21 mm Hg during EECP; ϩ93%; PϽ0.0001) and mean intracoronary pressures (88Ϯ9 to 102Ϯ16 mm Hg; ϩ16%; Pϭ0.006) with a decrease in systolic pressure (116Ϯ20 to 99Ϯ26 mm Hg; Ϫ15%; Pϭ0.002). The intracoronary Doppler measure of average peak velocity increased from 11Ϯ5 cm/s at baseline to 23Ϯ5 cm/s during EECP (ϩ109%; Pϭ0.001). The TIMI frame count, a quantitative angiographic measure of coronary flow, showed a 28% increase in coronary flow during EECP compared with baseline (Pϭ0.001). Conclusions-EECP unequivocally and significantly increases diastolic and mean pressures and reduces systolic pressure in the central aorta and the coronary artery. Coronary artery flow, determined by both Doppler and angiographic techniques, is increased during EECP. The combined effects of systolic unloading and increased coronary perfusion pressure provide evidence that EECP may serve as a potential mechanical assist device.

Clinical effects of enhanced external counterpulsation treatment in patients with ischemic heart failure

“…In our study, patients were on optimal tolerated CAD and HF regime but continue to have severe symptoms with low functional capacity. EECP is a noninvasive, pneumatic technique that utilizes electrocardiogram gated diastolic inflation of a series of lower-extremity cuffs to effectively increase diastolic and mean intracoronary pressures as well as coronary flow while reducing systolic pressure in the central aorta and the coronary artery (18). In addition, EECP improves diastolic filling, decreases left ventricular end-diastolic pressure, and improves LV peak filling rate, end-diastolic volume, and time to peak filling rate (19).…”

Enhanced external counterpulsation does not alter arterial stiffness in patients with angina

“…23 On the other hand, several studies have demonstrated increased myocardial perfusion with associated release of endothelial growth factors, improved coronary endothelial function, and decreased neurohumeral factors, which may reflect improved ventricular hemodynamics. 3,[5][6][7] Hence, the bulk of the evidence to date suggests that EECP exerts its sustained clinical benefits through improvements in cardiac status, rather than benefitting the peripheral vascular system. Our study result supports this theory by failing to demonstrate any measurable change in central or peripheral arterial stiffness immediately or 4 months post completion of EECP therapy.…”

Efficacy of Enhanced External Counterpulsation (EECP) in Nepalese chronic stable Angina patient: a single centre prospective study at Shahid Gangalal National Heart Center (SGNHC)

“…4 The hemodynamic effects are similar to intra-aortic balloon pumping (IABP). 6,7 A treatment procedure involves one to two hours/day for a total of 35 hours of therapy. Several studies around the world have shown patient improvement with lowering in Canadian Cardiovascular Society Classification (CCS) angina class.…”

“…15 However, the mechanisms by which these hemodynamic effects lead to a reduction of angina are poorly understood, although the effect is similar to IABP. 7 There is accumulating evidence suggesting that EECP treatment improves endothelial function, which may contribute to the clinical benefit . 8 EECP treatment is associated with an immediate increase in blood flow in multiple vascular beds including the coronary arterial circulation.…”

“…8 EECP treatment is associated with an immediate increase in blood flow in multiple vascular beds including the coronary arterial circulation. 7 This increase in blood flow may result in increased endothelial shear stress, 16 which enhances endothelial function by stimulating the release of the vasodilatory mediator nitric oxide and reduces the release of the vasocontractile endothelin-1. 15,[17][18][19] However, most of the experience is from small animal or human uncontrolled studies, and the mechanism of the sustained antianginal benefit with EECP remains unclear.…”