Enhanced external counter pulsation in treatment of refractory angina pectoris: two year outcome and baseline factors associated with treatment failure

Effectiveness of Enhanced External Counterpulsation Treatment on Symptom Burden, Medication Profile, Physical Capacity, Cardiac Anxiety, and Health-Related Quality of Life in Patients With Refractory Angina Pectoris

BACKGROUND

Patients with refractory angina pectoris experience recurrent symptoms that limit their functional capacity, including psychological distress and impaired health-related quality of life (HRQoL), despite optimized medical therapy. Enhanced external counterpulsation (EECP) is an evidence-based alternative noninvasive treatment. Although physical well-being and mental well-being are equally important components of health, few studies have investigated the psychological effects of EECP in patients with refractory angina pectoris.

OBJECTIVE

The aim of this study was to evaluate the effects of EECP treatment in patients with refractory angina pectoris regarding medication profile, physical capacity, cardiac anxiety, and HRQoL.

METHODS

This quasi-experimental study with 1-group pretest-posttest design includes a 6-month follow-up of 50 patients (men, n = 37; mean age, 65.8 years) who had undergone 1 EECP course. The following pretreatment and posttreatment data were collected: medication use, 6-minute walk test results, functional class according to the Canadian Cardiovascular Society, and self-reported (ie, questionnaire data) cardiac anxiety and HRQoL. In addition, the questionnaires were also completed at a 6-month follow-up.

RESULTS

After EECP treatment, patients used significantly less nitrates (P < .001), walking distance increased on average by 46 m (P < .001), and Canadian Cardiovascular Society class improved (P < .001). In addition, all but 1 subscale of cardiac anxiety and all HRQoL components improved significantly (P < .05). The positive effects for cardiac anxiety and HRQoL were maintained at the 6-month follow-up.

CONCLUSIONS

Enhanced external counterpulsation treatment resulted in reduced symptom burden, improved physical capacity, and less cardiac anxiety, leading to increased physical activity and enhanced life satisfaction for patients with refractory angina pectoris. Enhanced external counterpulsation treatment should be considered to improve the life situation for these patients.

Predictors of treatment benefits after enhanced external counterpulsation in patients with refractory angina pectoris

Background

Enhanced external counterpulsation (EECP) is a noninvasive treatment that can decrease limiting symptoms in patients with refractory angina pectoris (RAP). Identifying responders to EECP is important as EECP is not widely available and relatively time intensive.

Hypothesis

The effect of EECP treatment on physical capacity in patients with RAP can be predicted from baseline patient characteristics and clinical factors.

Methods

This explorative study includes all patients from a cardiology clinic who had finished one EECP treatment and a 6 min walk test pre and post EECP. Clinical data, including Canadian Cardiovascular Society (CCS) classification and left ventricular ejection fraction (LVEF), were assessed before treatment. If patients increased their 6 min walking distance (6MWD) by 10% post EECP, they were considered responders.

Results

Of the 119 patients (men = 97, 40–91 years), 49 (41.2%) were responders. Multinomial regression analysis showed that functional status (i.e., CCS class ≥3) (OR 3.10, 95% CI 1.12–8.57), LVEF <50% (OR 2.82, 95% CI 1.02–7.80), and prior performed revascularization (i.e., ≤ 1 type of intervention) (OR 2.77, 95% CI 1.06–7.20) were predictors of response to EECP (p < .05, Accuracy 63.6%). Traditional risk factors (e.g., gender, smoking, and comorbidities) did not predict response.

Conclusions

EECP treatment should be considered preferentially for patients that have a greater functional impairment, evidence of systolic left ventricular dysfunction, and exposure to fewer types of revascularization, either PCI or CABG. Improvement in 6MWD post EECP could imply improvement in physical capacity, which is a likely contributor to improved well‐being among patients with RAP.

Effects of external counter-pulsation on endothelial function assessed by peripheral artery tonometry, levels of glycaemia and metabolic markers in individuals with type 2 diabetes mellitus

BACKGROUND AND AIMS

External counter-pulsation (ECP) generates sheer stress thereby improving endothelial function and anginal symptoms in coronary artery disease. Endothelial dysfunction is also involved in the pathogenesis of T2DM. The aim of this pilot study was to investigate the use of ECP at different doses in improving endothelial function and glycaemic markers in T2DM.

METHODS

This prospective study involved 46 subjects with T2DM randomly assigned to receive 35 sessions of ECP at different regimens (0.5 h versus 1 h) and duration (7 versus 12 weeks). Endothelial function was evaluated by reactive hyperaemia index (RHI) via peripheral arterial tonometry at the start, midpoint and end of study. Other secondary outcomes included fasting glucose, HOMA-IR, HbA1c, blood pressure, lipid profile, weight and vibration sense.

RESULTS

There was no change in RHI across all 3 regimens of ECP individually or collectively at the end of the study (ΔRHI +0.01%, p = 0.458). Glycaemic markers also remained unchanged at endpoint. Subgroup analysis showed an improvement in RHI (ΔRHI +20.6%, p = 0.0178) in subjects with more severe endothelial dysfunction at baseline.

CONCLUSION

ECP did not show a beneficial effect on endothelial function or glycemic control in this South-East Asian population with T2DM at any of the three regimens. This may partly be explained by less severe endothelial dysfunction and less insulin resistance in our population at baseline.

Refractory angina frequencies during 7 weeks treatment by enhanced external counterpulsation in coronary artery disease patients with and without diabetes

Background:

Refractory angina is a clinical diagnosis which implies to chronic pain due to coronary artery insufficiency and it is often resistant to routine cardiac treatment. The present study conducted to compare changes in refractory angina frequencies during 7 weeks treatment by enhanced external counterpulsation (EECP) in coronary artery disease (CAD) patients with and without diabetes.

Methods:

In this retrospective study, 94 CAD patients (30 diabetics vs. 64 nondiabetics) who referred to cardiac rehabilitation department of Imam Ali Hospital of Kermanshah, Iran, during January 2006–2014 were assessed. The interventional method was EECP and medical records and frequencies of self-reported chest pain were research instruments. Data were analyzed through Chi-square test, mixed repeated measures, and Bonferroni test.

Results:

Frequencies of pain in both diabetic and nondiabetic groups during 7 weeks had linear reduction, but this reduction was significant only among nondiabetic patients (P < 0.0005). Furthermore, the significant reduction in frequencies of pain among this group begins after the 5^th week.

Discussion:

Diabetes is one of the obstacles to the successful control of pain frequencies by the EECP in patients with CAD. Future studies may pay attention to the confounding role of diabetes in improving the severity of chest pain.

[Impact of external counterpulsation on microcirculation in patients with coronary heart disease complicated by chronic heart failure after surgical and endovascular myocardial revascularization]

AIM

To study the impact of external counterpulsation (ECP) on endothelial function and microcirculation in patients after myocardial revascularization (stenting and coronary artery bypass grafting) for functional class (FC) II-III chronic heart failure (CHF).

SUBJECTS AND METHODS

Sixty patients aged 50 to 75 years after myocardial revascularization for FC II-III CHF were examined. All the patients received one-hour ECP sessions 5 times per week. The treatment cycle consisted of 35 sessions. To evaluate the microcirculatory bed, capillary blood flow was studied by laser Doppler flowmetry.

RESULTS

The cycle of ECP in patients with FC II-III CHF after myocardial revascularization had a corrective effect on the microhemodynamic system. Microcirculatory changes were due to the normalized myogenic and neurogenic tone of arterioles and to increased oscillations in the endothelial range. The pronounced beneficial effect of ECP on the cardiovascular system in the examined patients was confirmed by a significant increase in exercise tolerance and by a statistically significant improvement in the results of 6-minute walk test. There was a decrease in FC heart failure.

CONCLUSION

ECP is an effective, non-invasive treatment in patients with heart failure.

Enhanced External Counterpulsation Therapy: Past, Present, and Future

External counterpulsation therapy was first developed over half a century ago as a resuscitative tool to support the failing heart and was based on hemodynamic principles of the intraaortic balloon pump. Over the course of last few decades, it has evolved into the modern enhanced external counterpulsation (EECP) therapy, which has proven to be a safe, effective, and low-cost noninvasive treatment for patients with debilitating angina and chronic heart failure who are poor candidates for revascularization procedures and have suboptimal results from other therapies. Numerous studies have shown EECP to be efficacious in patients with chronic angina, with its effects lasting for several years after completion of therapy. Besides being safe in patients with coexisting left ventricular dysfunction, there is emerging evidence that EECP therapy may result in improvement in exercise capacity and oxygen consumption in heart failure patients. Several mechanisms have been postulated to explain the therapeutic effects of EECP, including improvement in endothelial function, promotion of angiogenesis and new collaterals, reduction in atherosclerotic burden, improvement in ventricular function, and peripheral training effects analogous to that of exercise. With greater understanding of these complex mechanisms, possible applications of EECP have broadened in recent years, with its use being studied in conditions like hepatorenal syndrome, erectile dysfunction, and restless leg syndrome. This review article offers a historical perspective on the origins of EECP, an overview of our current understanding of its physiological effects, and a glimpse at its future utilization in clinical practice.

Efficacy of Enhanced External Counterpulsation in Patients With Chronic Refractory Angina on Canadian Cardiovascular Society (CCS) Angina Class: An Updated Meta-Analysis

A growing number of patients with chronic artery disease suffer from angina, despite the optimal medical management (ie, β-blockers, calcium channel blockers, and long-acting nitrates) and revascularization. Currently, enhanced external counterpulsation (EECP) therapy has been verified as a noninvasive, safe therapy for refractory angina. The study was designed to evaluate the efficacy of EECP in patients with chronic refractory angina according to Canadian Cardiovascular Society (CCS) angina class.We identified systematic literature through MEDLINE, EMBASE, the Cochrane Clinical Trials Register Database, and the ClinicalTrials. gov Website from 1990 to 2015. Studies were considered eligible if they were prospective and reported data on CCS class before and after EECP treatment. Meta-analysis was performed to assess the efficacy of EECP therapy by at least 1 CCS angina class improvement, and proportion along with the 95% confidence interval (CI) was calculated. Statistical heterogeneity was calculated by I statistic and the Q statistic. Sensitivity analysis was addressed to test the influence of trials on the overall pooled results. Subgroup analysis was applied to explore potential reasons for heterogeneity.Eighteen studies were enrolled in our meta-analysis. Pooled analysis showed 85% of patients underwent EECP had a reduction by at least one CCS class (95%CI 0.81-0.88, I = 58.5%, P < 0.001). The proportion of patients enrolled at primarily different studies with chronic heart failure (CHF) improved by at least 1 CCS class was about 84% after EECP (95%CI 0.81-0.88, I = 32.7%, P = 0.1668). After 3 large studies were excluded, the pooled proportion was 82% (95%CI 0.79-0.86, I = 18%, P = 0.2528). Funnel plot indicated that some asymmetry while the Begg and Egger bias statistic showed no publication bias (P = 0.1495 and 0.2859, respectively).Our study confirmed that EECP provided an effective treatment for patients who were unresponsive to medical management and/or invasive therapy. However, the long-term benefits of EECP therapy needed further studies to evaluate in the management of chronic refractory angina.

Overview of the 2012 Food and Drug Administration circulatory system devices panel meeting on the reclassification of external counterpulsation, intra-aortic balloon pump, and non-roller-type cardiopulmonary bypass blood pump devices

The Food and Drug Administration held a Circulatory System Devices Advisory Panel meeting, December 5 and 6, 2012, to review the classification or potential reclassification of the following device types: external counterpulsation, intra-aortic balloon pump (IABP), and non-roller-type cardiopulmonary bypass blood pumps. These 3 devices are preamendment (Medical Device Amendments of 1976) class III devices. The advisory panel discussed the data and provided recommendations for reclassification of these devices. The panel recommended reclassification of ECP to class II for stable angina pectoris and to retain a class III for all other indications. For IABP, the recommendation was to reclassify IABP to class II for several indications (acute coronary syndrome, cardiac and noncardiac surgery, and heart failure complications) and remain class III for all other indications. As for non-roller type, the panel recommended that for cardiopulmonary bypass and temporary circulatory bypass, these devices should be reclassified to class II while retaining a class III device status for all other indications, including ventricular support both for hemodynamically unstable patients and for prophylactic support in high-risk percutaneous interventions.

Reduced peripheral vascular reactivity in refractory angina pectoris: Effect of enhanced external counterpulsation

AIMS

To examine if the skin microvascular bed is altered and can be modified by enhanced external counterpulsation (EECP) in patients with chronic refractory angina.

METHODS

Twenty patients diagnosed with refractory angina were divided into EECP (n = 10) or no EECP (n = 10) groups. The data were compared to matched healthy subjects (n = 20). The cutaneous forearm microvascular blood flow was measured by Laser-Doppler flowmetry. The vascular responsiveness to iontophoretic administration of acetylcholine (ACh), sodium nitroprusside (SNP) and local skin warming were studied. Measurements of Canadian Cardiovascular Society (CCS)-class, blood pressure and plasma samples were registered.

RESULTS

EECP patients showed reduced CCS-class compared to no EECP (P < 0.05). Both EECP and no EECP (P < 0.05) groups had decreased systolic blood pressure (SBP) as compared to SBP at baseline (P < 0.05). There was no difference in resting blood flow between the two refractory groups at baseline as well as after EECP and seven weeks of follow-up. Responses to heating, the responses to ACh and SNP in the cutaneous microcirculation were lower in both groups of refractory angina patients as compared to healthy subjects (P < 0.05). EECP patients corresponded positively to the treatment shown by reduced plasma level of soluble interleukin-2 receptor and CCS-class.

CONCLUSIONS

Refractory angina patients have reduced responsiveness in their cutaneous microcirculation to ACh, SNP and heat compared to healthy subjects. Although EECP reduced the CCS-class, this effect was not associated with improvements in responsiveness of the cutaneous microcirculation.

Recent advances in the management of chronic stable angina II. Anti-ischemic therapy, options for refractory angina, risk factor reduction, and revascularization

The objectives in treating angina are relief of pain and prevention of disease progression through risk reduction. Mechanisms, indications, clinical forms, doses, and side effects of the traditional antianginal agents - nitrates, β-blockers, and calcium channel blockers - are reviewed. A number of patients have contraindications or remain unrelieved from anginal discomfort with these drugs. Among newer alternatives, ranolazine, recently approved in the United States, indirectly prevents the intracellular calcium overload involved in cardiac ischemia and is a welcome addition to available treatments. None, however, are disease-modifying agents. Two options for refractory angina, enhanced external counterpulsation and spinal cord stimulation (SCS), are presented in detail. They are both well-studied and are effective means of treating at least some patients with this perplexing form of angina. Traditional modifiable risk factors for coronary artery disease (CAD) - smoking, hypertension, dyslipidemia, diabetes, and obesity - account for most of the population-attributable risk. Individual therapy of high-risk patients differs from population-wide efforts to prevent risk factors from appearing or reducing their severity, in order to lower the national burden of disease. Current American College of Cardiology/American Heart Association guidelines to lower risk in patients with chronic angina are reviewed. The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial showed that in patients with stable angina, optimal medical therapy alone and percutaneous coronary intervention (PCI) with medical therapy were equal in preventing myocardial infarction and death. The integration of COURAGE results into current practice is discussed. For patients who are unstable, with very high risk, with left main coronary artery lesions, in whom medical therapy fails, and in those with acute coronary syndromes, PCI is indicated. Asymptomatic patients with CAD and those with stable angina may defer intervention without additional risk to see if they will improve on optimum medical therapy. For many patients, coronary artery bypass surgery offers the best opportunity for relieving angina, reducing the need for additional revascularization procedures and improving survival. Optimal medical therapy, percutaneous coronary intervention, and surgery are not competing therapies, but are complementary and form a continuum, each filling an important evidence-based need in modern comprehensive management.