A novel external counterpulsation system for coronary artery disease and heart failure: pilot studies and initial clinical experiences

Novel external counterpulsation system, compact counterpulsation, was effective to treat severe ischemic heart failure: a case report

Compact counterpulsation (CP) is a novel external counterpulsation system. The preoperative clinical utility of compact CP therapy in patients has not been established. In the present report, we describe a case wherein compact CP therapy was successfully used to treat severe ischemic heart failure. A 70-year-old man was diagnosed with ischemic heart disease and mitral valve regurgitation at 61 years of age. Therefore, he underwent coronary artery bypass and mitral valve plasty. The patient's condition started to gradually deteriorate at 68 years of age, and he became progressively dependent on catecholamine support. Mitral valve regurgitation recurred, which caused worsening of heart function. Before a mitral valve replacement, the patient had been treated with compact CP therapy to improve heart function and general condition. The patient's clinical condition improved with compact CP therapy after only ten sessions; in addition, he could be weaned off catecholamine support. No adverse effects were observed, and therefore, he could complete the CP therapy as an outpatient. Mitral valve replacement was performed after a total of 44 sessions. The patient had an uneventful postoperative course and was discharged on the 18th postoperative day. Compact CP therapy was thus performed on our patient without any discomfort and appears to be an effective treatment for patients with severe ischemic heart failure.

The hemodynamic effect of the support mode for the intra-aorta pump on the cardiovascular system

Intra-aorta pump is a novel rotary ventricular assist device. Because of the special structure and connection with the native heart, the hemodynamic effect of support mode of this pump on the cardiovascular system is not clear. In this work, three support modes, including "constant speed" mode, "co-pulse" mode, and "counter-pulse" mode, have been designed for the intra-aorta pump to evaluate the hemodynamic effect of different support modes on the cardiovascular system. Simulation results demonstrate that that both "co-pulse" mode and "counter-pulse" mode can achieve better unloading performance than "constant speed" mode. The intra-aorta pump controlled by "co-pulse" mode is beneficial for improving coronary flow. Moreover, the external work, which is defined as the product of left ventricular pressure and cardiac output, under "co-pulse" mode is the minimum of the three support modes (0.783 w vs. 0.615 w vs. 0.702 w). The pulsatility ratio, defined as the ratio of the peak-to-peak value of arterial pressure (AP) to the mean arterial pressure value, under "co-pulse" mode is the maximum of the three modes (24% vs. 32.8% vs. 23.7%). The equivalent afterload value, which is the ratio of pulsatile pressure at the pump inflow and pulsatile pump flow, is larger than other support modes (0.596 mm Hg.s/mL vs. 0.9704 mm Hg.s/mL vs. 0.55 mm Hg.s/mL). In brief, the intra-aorta pump under "co-pulse" mode support is beneficial for improving myocardial perfusion and restoring pulsatility of AP, while "counter-pulse" mode is beneficial to the perfusion of vital organs.

Effect of external counterpulsation on cardiac work following cardiac surgery: implications of the mechanism responsible for clinical benefits

BACKGROUND

External counterpulsation (ECP) has been recognized as a non-invasive treatment for chronic refractory angina or heart failure. However, the mechanisms responsible for the clinical benefits of ECP therapy remain elusive. Moreover, the clinical significance of ECP therapy for postoperative patients has not been established yet.

METHODS

Six adult patients received ECP therapy for 60 min under pulmonary artery catheter monitoring after cardiac surgery. Hemodynamic data were obtained before ECP therapy (pre-ECP), 20 min after ECP was commenced (20-min-ECP), 40 min after ECP was commenced (40-min-ECP), and after ECP therapy (post-ECP).

RESULTS

The mean right atrial pressure (pre-ECP: 9 ± 4 mmHg; 20-min-ECP: 12 ± 5 mmHg; 40-min-ECP: 12 ± 4 mmHg; and post-ECP: 9 ± 4 mmHg), pulmonary wedge pressure (16 ± 6 mmHg, 20 ± 7 mmHg, 20 ± 7 mmHg, and 17 ± 7 mmHg, respectively), cardiac index (2.4 ± 0.4 l/min/m(2), 2.8 ± 0.6 l/min/m(2), 2.7 ± 0.5 l/min/m(2), and 2.5 ± 0.4 l/min/m(2), respectively), cardiac work index (2.5 ± 0.4 kgm/m(2), 3.3 ± 0.8 kgm/m(2), 3.1 ± 0.8 kgm/m(2), and 2.6 ± 0.5 kgm/m(2), respectively), and left ventricular stroke work index (32 ± 7 gm/m(2), 41 ± 12 gm/m(2), 39 ± 12 gm/m(2), and 33 ± 8 gm/m(2), respectively) significantly (p<0.05) increased after ECP was commenced (pre-ECP vs. 20-min-ECP) and decreased after ECP was discontinued (40-min-ECP vs. post-ECP). Significant (p<0.001) diastolic augmentation (20-min-ECP: 24 ± 6%, 40-min-ECP: 23 ± 5%) and systolic unloading (3 ± 1%, and 3 ± 1%, respectively) were obtained. No clinical adverse effects were observed.

CONCLUSIONS

ECP increases venous return, cardiac output, and cardiac work in addition to diastolic augmentation and systolic unloading. These actions may play important roles in the clinical benefits of ECP therapy. Our data also suggest that ECP is beneficial for patients undergoing cardiac surgery.

A novel counterpulsation mode of rotary left ventricular assist devices can enhance myocardial perfusion

The effect of rotary left ventricular assist devices (LVADs) on myocardial perfusion has yet to be clearly elucidated, and several studies have shown decreased coronary flow under rotary LVAD support. We have developed a novel pump controller that can change its rotational speed (RS) in synchronization with the native cardiac cycle. The aim of our study was to evaluate the effect of counterpulse mode, which increases the RS in diastole, during coronary perfusion. Experiments were performed on ten adult goats. The EVAHEART LVAD was installed by the left ventricular uptake and the descending aortic return. Ascending aortic flow, pump flow, and coronary flow of the left main trunk were monitored. Coronary flow was compared under four conditions: circuit-clamp, continuous mode (constant pump speed), counterpulse mode (increased pump speed in diastole), and copulse mode (increased pump speed in systole). There were no significant baseline changes between these groups. In counterpulse mode, coronary flow increased significantly compared with that in continuous mode. The waveform analysis clearly revealed that counterpulse mode mainly resulted in increased diastolic coronary flow. In conclusion, counterpulse mode of rotary LVADs can enhance myocardial perfusion. This novel drive mode can provide great benefits to the patients with end-stage heart failure, especially those with ischemic etiology.