Enhanced external counterpulsation ameliorates endothelial dysfunction and elevates exercise tolerance in patients with coronary artery disease

Hemodynamics of ventricular-arterial coupling under enhanced external counterpulsation: An optimized dual-source lumped parameter model

BACKGROUND AND OBJECTIVE

Enhanced external counterpulsation (EECP) is a mechanically assisted circulation technique widely used in the rehabilitation and management of ischemic cardiovascular diseases. It contributes to cardiovascular functions by regulating the afterload of ventricle to improve hemodynamic effects, including increased diastolic blood pressure at aortic root, increased cardiac output and enhanced blood perfusion to multiple organs including coronary circulation. However, the effects of EECP on the coupling of the ventricle and the arterial system, termed ventricular-arterial coupling (VAC), remain elusive. We aimed to investigate the acute effect of EECP on the dynamic interaction between the left ventricle and its afterload of the arterial system from the perspective of ventricular output work.

METHODS

A neural network assisted optimization algorithm was proposed to identify the ordinary differential equation (ODE) relation between aortic root blood pressure and flow rate. Based on the optimized order of ODE, a lumped parameter model (LPM) under EECP was developed taking into consideration of the simultaneous action of cardiac and EECP pressure sources. The ventricular output work, in terms of aortic pressure and flow rate cooperated with the LPM, was used to characterize the VAC of ventricle and its afterload. The VAC subjected to the principle of minimal ventricular output work was validated by solving the Euler-Poisson equation of cost function, ultimately determining the waveforms of aortic pressure and flow rate.

RESULTS

A third-order ODE can precisely describe the hemodynamic relationship between aortic pressure and flow rate. An optimized dual-source LPM with three energy-storage elements has been constructed, showing the potential in probing VAC under EECP. The LPM simulation results demonstrated that the VAC in terms of aortic pressure and flow rate yielded to the minimal ventricular output work under different EECP pressures.

CONCLUSIONS

The ventricular-arterial coupling under EECP is subjected to the minimal ventricular output work, which can serve as a criterion for determining aortic pressure and flow rate. This study provides insight for the understanding of VAC and has the potential in characterizing the performance of the ventricular and arterial system under EECP.

Enhanced external counterpulsation increases coronary flow reserve in coronary microvascular disease

OBJECTIVES

To investigates the outcomes of enhanced external counterpulsation (EECP) among coronary microvascular disease (CMD) patients.

METHODS

Coronary microvascular disease patients were separated into the EECP (n=41) and control cohorts (n=42). Prior to and following the 4-week EECP program, coronary flow reserve (CFR) was recorded using transthoracic Doppler echocardiography. The serum endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) contents were analyzed by ELISA. Quality of life (QoL) was assessed by the Seattle Angina Questionnaire (SAQ) and the Canadian Cardiovascular Society (CCS) angina class.

RESULTS

After four weeks, CFR was substantially enhanced in the EECP versus control cohort (p<0.05). Endothelin-1 was strongly diminished whereas eNOS was considerably upregulated in the EECP cohort. EECP also enhanced patients' SAQ scores and decreased the CCS angina class.

CONCLUSION

Enhanced external counterpulsation may improve CFR and enhance the CMD patient QoL.

Impact of Enhanced External Counter-pulsation Therapy on Glycaemic Control in People With Prediabetes and Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis

Background: Enhanced external counter-pulsation (EECP) therapy is approved for refractory angina in coronary artery disease (CAD). EECP is being explored as a treatment modality in type 2 diabetes mellitus (T2DM). Methods: The Embase, Web of Science, Cochrane Library, MEDLINE (PubMed), ClinicaltTrials. gov, CNKI database, Clinical Trials Registry-india (CTRI), and Google Scholar databases were searched for randomized controlled trials (RCTs) involving patients receiving EECP therapy in the intervention arm. The primary outcome was the changes in glycated haemoglobin (HbA1c). The secondary outcomes were the changes in blood glucose parameters, inflammatory markers and any adverse events. Results: Data from 3 RCTs involving 71 people with T2DM/prediabetes was analysed to find out the impact of EECP therapy compared with placebo. As compared with placebo, patients receiving EECP had significantly lower HbA1C immediately after completion of therapy (mean difference [MD] -0.70%, 95% confidence interval (CI) -0.95. -0.45;p<0.00001), at 2-4 weeks post completion of therapy (MD -1.04%, 95%CI -1.32. -0.77; p<0.00001) and 7-12 weeks after therapy completion (MD -0.98%, 95% CI -1.22, -0.74; p<0.00001). EECP therapy was well tolerated without any increased side effects (risk ratio 2.36, 95% CI 0.11-52.41; p=0.59. Conclusion: EECP therapy is effective in blood glucose and pressure lowering over at least 7-12 weeks of therapy completion. Blood glucose and pressure should be monitored with suitable modulation of drug doses to prevent hypoglycaemia and hypotension in patients with angina undergoing EECP therapy. The PROSPERO registration number is CRD42023434533.