Effect of enhanced external counterpulsation on coronary slow flow and its relation with endothelial function and...

Although enhanced external counterpulsation (EECP) showed short-term effects in improving coronary flow in patients with coronary slow flow (CSF), whether such improvement is durable remains uncertain, and the relationships between such improvement and changes in endothelial function as well as inflammatory markers have not been elucidated.

The aim of the present study was to investigate the effects of EECP on transthoracic coronary flow, flow-mediated dilatation (FMD), and high-sensitivity C-reactive protein (hsCRP) in patients with CSF.

Forty-five patients with documented CSF underwent transthoracic Doppler echocardiography (TTDE) for the assessment of coronary diastolic peak flow velocity (DPFV) and coronary flow reserve (CFR), and measurements of FMD and hsCRP; they were then nonrandomly assigned to two groups. Subjects in the control group (n = 24) received only medical therapy, and those in the EECP group (n = 21) were additionally treated with the 36 one-hour sessions of EECP. After 8 weeks of medical/EECP therapy, TTDE, FMD, and hsCRP examinations were repeated, and TTDE was additionally repeated after the 6-month clinical follow-up.

In the EECP group, resting DPFV, hyperemic DPFV, and CFR were significantly increased shortly after therapy (p < 0.001) and the improvement was maintained up to the 6-month follow-up, whereas in the control group those variables were not statistically increased. Meanwhile, hsCRP significantly decreased and FMD increased after therapy in the EECP group (p < 0.001). In all subjects, CFR improvement was negatively correlated with hsCRP change and positively correlated with FMD increase (p < 0.001).

EECP may have a durable effect in improving coronary flow in patients with CSF. Such improvement is related to the favorable effects of EECP on vascular inflammation and endothelial function.