Safety and effectiveness of Enhanced External Counterpulsation (EECP) in Refractory Angina Patients: Systematic Reviews and Meta-Analysis

Enhanced external counterpulsation (EECP) is believed to be a non-invasive treatment for coronary artery disease and angina. The aim of this study was to determine the safety and effectiveness of EECP in refractory angina patients through a systematic reviews and meta-analysis. We conducted a comprehensive search of the literature published on PubMed, Cochrane library, Scopus, ScienceDirect, Trip Database and Google Scholar databases using appropriate keywords and specific strategy with no time limit. Having selected and screened the studies based on the defined inclusion and exclusion criteria and evaluating their quality based on the Cochrane checklist. For the meta-analysis,the Mantel-Haenszel method or the generic Inverse Variance was used. Analyses were done with Review Manager 5.2 software. A number of 299 studies were initially reviewed and finally, seventeen studies were included in the meta-analysis based on the inclusion and exclusion criteria. Also, thirteen outcomes were analyzed and the results of meta-analysis in twelve outcomes including (Systolic Blood Pressure (7 studies), Diastolic Blood Pressure (7 studies), Pulse Pressure (4 studies), Mean Arterial Pressures (4 studies), Heart Rate (6 studies), Angina episodes (7 studies), Walking distance (2 studies),Canadian Cardiovascular Society classification (6 studies), Flow-Mediated Dilation (3 studies), Daily Nitrate Usage (4 studies), Exercise Treadmill Test-Time (2 studies), ST-segment depression (2 studies)demonstrated a significant clinical advantage in the EECP treatment effectiveness in patients with angina. No significant difference was observed regarding EECP usefulness (P = 0.18) in the outcome of brachial artery diameter (2 studies). Based on the meta-analysis, the results indicate the safety and effectiveness of EECP in patients with angina pectoris and indicate the usefulness of this treatment in these patients. In general, the authors believe that the general conclusion in this regard requires some studies with a large sample size and a control group assignment.

Acute Hemodynamic Responses to Enhanced External Counterpulsation in Patients With Coronary Artery Disease

Purpose: Enhanced external counterpulsation is a non-invasive treatment that increases coronary flow in patients with coronary artery disease (CAD). However, the acute responses of vascular and blood flow characteristics in the conduit arteries during and immediately after enhanced external counterpulsation (EECP) need to be verified.Methods: Forty-two patients with CAD and 21 healthy controls were recruited into this study to receive 45 min-EECP. Both common carotid arteries (CCAs), namely, the left carotid (LC) and right carotid (RC), the right brachial (RB), and right femoral (RF) artery were imaged using a Color Doppler ultrasound. The peak systolic velocity (PSV), end-diastolic velocity (EDV), mean inner diameter (ID), resistance index (RI), and mean flow rate (FR) were measured and calculated before, during, and after the 45 min-EECP treatment.Results: During EECP, in the CCAs, the EDV was significantly decreased, while the RI was markedly increased in the two groups (both P < 0.01). However, immediately after EECP, the RI in the RC was significantly lower than that at the baseline in the patients with CAD (P = 0.039). The FR of the LC was markedly increased during EECP only in the CAD patients (P = 0.004). The PSV of the patients with CAD was also significantly reduced during EECP (P = 0.015) and immediately after EECP (P = 0.005) compared with the baseline. Moreover, the ID of the LC, RB, and RF was significantly higher immediately after EECP than that at the baseline (all P < 0.05) in the patients with CAD. In addition, they were also higher than that in the control groups (all P < 0.05). Furthermore, by the subgroup analysis, there were significant differences in the FR, PSV, and RI between females and males during and immediately after EECP (all P < 0.05).Conclusions: Enhanced external counterpulsation creates different responses of vascular and blood flow characteristics in carotid and peripheral arteries, with more significant effects in both the carotid arteries. Additionally, the beneficial effects in ID, blood flow velocity, RI, and FR after 45 min-EECP were shown only in the patients with CAD. More importantly, acute improvement of EECP in the FR of the brachial artery was showed in males, while the FR and RI of the carotid arteries changed in females.

Clinical effects of the enhanced external counterpulsation therapy in patients with ischemic chronic heart failure exacerbation COVID-19

Objectives The aim of the study was to assess the effects of the enhanced external counterpulsation (EECP) therapy as a rehabilitation method in patients with ischemic chronic heart failure (CHF) after COVID-19. Methods 54 (n=54) stable symptomatic CHF (NYHA, functional class I-II; 35%≤LVEF≤50%) subjects (44 male and 10 female; mean age 61±9,8) with prior anamnesis of CAD, at least one myocardial infarction got the exacerbation of CHF after COVID-19 episode. They were randomized in a 2:1 manner into either 35 1-hour 250–300 mm Hg sessions of EECP (n=36; 30 male, 6 female) or Sham-EECP (n=18; 14 male, 4 female). All subjects had been received optimal CHF and CAD drug therapy. At baseline, a month and half a year after EECP course every subject was examined with echocardiography and 6-minute walk test. Results All 36 active EECP treatment group subjects improved by at least 1 NYHA class, 66% of them had no heart failure symptoms post treatment (p<0.01). 84% of treatment group pts. had sustained NYHA class improvement at half a year follow-up (p<0.01), compared with baseline. There was significant difference between LVEF 44±6,5% at baseline vs post-EECP LVEF 50±4,6% (p<0.01) in active EECP treatment group subjects. At the same time there were no significant changes of NYHA class and LVEF in Sham-EECP subjects. No one subject dies after half a year of follow up. Conclusions Enhanced external counterpulsation (EECP) therapy sustainably improves NYHA functional class and LVEF in patients with ischemic CHF exacerbation after COVID-19. FUNDunding Acknowledgement Type of funding sources: None.

Hemodynamic Responses in Carotid Bifurcation Induced by Enhanced External Counterpulsation Stimulation in Healthy Controls and Patients With Neurological Disorders

Enhanced external counterpulsation is a Food and Drug Administration–approved, non-invasive, assisted circulation therapy for ischemic cardiovascular and cerebrovascular diseases. Previous studies have confirmed that EECP stimulation induces largely different cerebral hemodynamic responses in patients with ischemic stroke and healthy controls. However, the underlying mechanisms remain uncertain. We hypothesize that different blood redistributions at the carotid bifurcation may play a key role. Ten subjects were enrolled in this study, namely, five patients with neurological disorders and five young healthy volunteers as controls. Magnetic resonance angiography (MRA) was performed on the carotid artery. All the subjects received a single session of EECP treatment, with external cuff pressures ranging from 20 to 40 kPa. Vascular ultrasound measurements were taken in the common carotid artery (CCA), external carotid artery (ECA) and internal carotid artery (ICA). Three-dimensional patient-specific numerical models were developed to calculate the WSS-derived hemodynamic factors. The results indicated that EECP increased CCA and ECA blood flow in both groups. The ICA blood flow in the patient group exhibited a mean increase of 6.67% during EECP treatment compared with the pre-EECP condition; a mean decrease of 9.2% was observed in the healthy control group. EECP increased the averaged wall shear stress (AWSS) throughout the carotid bifurcation in the patient group; the ICA AWSS of the healthy group decreased during EECP. In both groups, the oscillatory shear index (OSI) in the ICA increased proportionally with external cuff pressure. In addition, the relative resident time (RRT) was constant or slightly decreased in the CCA and ECA in both groups but increased in the ICA. We suggest that the benefits of EECP to patients with neurological disorders may partly result from blood flow promotion in the ICA and increase in WSS at the carotid bifurcation. In the healthy subjects, the ICA blood flow remained constant during EECP, although the CCA blood flow increased significantly. A relatively low external cuff pressure (20 kPa) is recommended as the optimal treatment pressure for better hemodynamic effects. This study may play an important role in the translation of physiological benefits of EECP treatment in populations with or without neurological disorders.