An update on enhanced external counterpulsation

Can enhanced external counter pulsation as a non-invasive modality be useful in patients with ischemic cardiomyopathy after coronary artery bypass grafting?

Background

Angina symptom in patients with ischemic cardiomyopathy (ICM) after coronary artery bypass grafting (CABG) surgery is a major challenging problem in practice. The choice among different treatment modalities available can be judged by different parameters especially measuring the risk/cost ratio to achieve the benefit. Enhanced external counter pulsation (EECP) is one of safest noninvasive modality for treatment of angina as well as it has an anti-failure effect.

Patients and method

42 patients with ICM after CABG were suffering from stable angina and were treated at Al-Hayat Cardiology Centre in Tanta City (ACC). 20 patients of them (group A) received 35 sessions of EECP plus their anti-ischemic and anti-failure treatment, while the other 22 patients (group B) received only medical treatment and were followed up for 3 months regarding their angina class, functional class, frequency of angina attack, frequency of sublingual nitrate and rate of rehospitalization when needed during follow up period.

Results

Despite both groups had nearly similar severity of symptoms regarding the CCS class and NYHA class, yet patients in group A experienced significant improvement in comparison to patients in group B (p-value = .005, p-value = .002 respectively), and this was reflected on frequency of angina and need for sublingual nitrates per week which showed significant decrease in group A (p-value = .001).

Conclusion

As a non-invasive treatment modality EECP is very effective in improving the symptoms of angina and heart failure when combined with medical treatment in patients with ICM after CABG.

Enhanced External Counterpulsation and Short-Term Recovery From High-Intensity Interval Training

PURPOSE

Enhanced external counterpulsation (EECP) is a recovery strategy whose use has increased in recent years owing to the benefits observed in the clinical setting in some cardiovascular diseases (ie, improvement of cardiovascular function). However, its claimed effectiveness for the enhancement of exercise recovery has not been analyzed in athletes. The aim of this study was to determine the effectiveness of EECP on short-term recovery after a fatiguing exercise bout.

METHODS

Twelve elite junior triathletes (16 [2] y) participated in this crossover counterbalanced study. After a high-intensity interval training session (6 bouts of 3-min duration at maximal intensity interspersed with 3-min rest periods), participants were assigned to recover during 30 min with EECP (80 mm Hg) or sham (0 mm Hg). Measures of recovery included performance (jump height and mean power during an 8-min time trial), metabolic (blood lactate concentration at several time points), autonomic (heart-rate variability at several time points), and subjective (rating of perceived exertion [RPE] and readiness to compete) outcomes.

RESULTS

There were no differences between EECP and sham in mean RPE or power output during the high-intensity interval training session, which elicited a significant performance impairment, vagal withdrawal, and increased blood lactate and RPE in both EECP and sham conditions (all P < .05). No significant differences were found in performance, metabolic, or subjective outcomes between conditions at any time point. A significantly lower high-frequency power (P < .05, effect size = 1.06), a marker of parasympathetic activity, was observed with EECP at the end of the recovery phase.

CONCLUSION

EECP did not enhance short-term recovery after a high-intensity interval training session in healthy, highly trained individuals.

Effects of enhanced external counterpulsation on skeletal muscle gene expression in patients with severe heart failure

Enhanced external counterpulsation (EECP) is a non-invasive treatment in which leg cuff compressions increase diastolic aortic pressure and coronary perfusion. EECP is offered to patients with refractory angina pectoris and increases physical capacity. Benefits in heart failure patients have been noted, but EECP is still considered to be experimental and its effects must be confirmed. The mechanism of action is still unclear. The aim of this study was to evaluate the effect of EECP on skeletal muscle gene expression and physical performance in patients with severe heart failure. Patients (n = 9) in NYHA III-IV despite pharmacological therapy were subjected to 35 h of EECP during 7 weeks. Before and after, lateral vastus muscle biopsies were obtained, and functional capacity was evaluated with a 6-min walk test. Skeletal muscle gene expression was evaluated using Affymetrix Hugene 1.0 arrays. Maximum walking distance increased by 15%, which is in parity to that achieved after aerobic exercise training in similar patients. Skeletal muscle gene expression analysis using Ingenuity Pathway Analysis showed an increased expression of two networks of genes with FGF-2 and IGF-1 as central regulators. The increase in gene expression was quantitatively small and no overlap with gene expression profiles after exercise training could be detected despite adequate statistical power. EECP treatment leads to a robust improvement in walking distance in patients with severe heart failure and does induce a skeletal muscle transcriptional response, but this response is small and with no significant overlap with the transcriptional signature seen after exercise training.

Clinical study in patients with ocular ischemic diseases treated with enhanced external counterpulsation combined with drugs

The aim of this study was to evaluate the clinical effect in patients with ocular ischemic diseases treated with enhanced external counterpulsation (EECP) combined with drugs. A total of 65 patients with carotid artery stenosis were included in this study. Group A consisted of 31 patients (43 eyes) treated with EECP and medication, and group B consisted of 34 patients (49 eyes) treated with medication alone. The clinical effect was analyzed by comparing the visual acuity, visual fields and optical hemodynamics between the two groups of patients. Ocular ischemic diseases mainly included ischemic optic neuropathy, central (branch) retinal artery occlusion, ophthalmoplegia externa and ocular ischemic syndrome. Significant improvement of visual acuity, visual fields and optical hemodynamics was observed in the patients of group A, and statistically significant differences were found between groups A and B (χ2=4.935, 7.124 and 5.478, respectively; P<0.05). In conclusion, ophthalmologists should observe for ocular ischemic diseases. The symptoms of the disease and the vision of the patient could be effectively improved by EECP, which has no evident complications.

The effects of enhanced external counterpulsation on health-related quality of life in patients with angina pectoris

BACKGROUND

The complicated concept of quality of life (QOL) has been considered as an important criterion for health outcomes in chronic diseases, such as heart disease, in recent years. The aim of this study was to evaluate the QOL of patients with angina pectoris after treatment with enhanced external counterpulsation (EECP).

MATERIALS AND METHODS

This quasi-experimental study was conducted on 64 patients with angina pectoris undergoing EECP who came to Shahid Chamran and Sina Hospitals in Isfahan. Sampling was performed by the convenient method. Data were collected using a questionnaire containing socio-demographic and clinical data. A standard questionnaire called 36-item Short-Form Health Survey was also used. Questionnaires were completed through interviews and phone calls in three stages (before, immediately and three months after the treatment). The results were analyzed using descriptive statistics (frequency, mean, and standard deviation) and analytical statistics (paired t-test and repeated measures test) in SPSS11.5.

FINDINGS

The obtained results demonstrated that the majority of patients were men (59.4%) and aged 56-71 years. In addition, 57.8% had hypertension and 56.3% had hyperlipidemia. A history of myocardial infarction was found in 70.3% of the subjects and the familial history of coronary artery disease was detected in73.4%. Although QOL evaluations showed improvements in all subscales immediately and three months after the treatment, the changes were not statistically significant in case of general health, role limitations due to physical problems and role limitations due to mental problems.

CONCLUSIONS

Similar to previous research, this study showed QOL to improve in patients who undergo EECP. This improvement will remain stable three months after the treatment in all subscales. Therefore, EECP is an efficient noninvasive method in treating patients with angina pectoris and in developing their QOL.

Enhanced external counterpulsation for chronic angina pectoris

BACKGROUND

Cardiovascular disease is a major cause of death in developed and developing countries. Refractory stable angina pectoris is, in general, inadequately responsive to conventional medical therapy.Enhanced external counterpulsation is a non-invasive treatment for patients with refractory angina and involves the placing of compressible cuffs around the calves and lower and upper thighs. These are inflated sequentially so that during early diastole they help propel blood back to the heart and when deflated at end of diastole allow the blood vessels to return to their normal state. It is claimed that enhanced external counterpulsation can help reduce aortic impedance and thereby alleviate some of the symptoms of angina.

OBJECTIVES

To assess the effects of enhanced external counterpulsation therapy in improving health outcomes for patients with chronic stable or refractory stable angina pectoris.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (2008, Issue 1), MEDLINE (1966 to February 2008), EMBASE (1980 to February 2008), LILACS via BIREME (to February 2008) and ISI Science Citation Index on Web of Science (to February 2008). No language restrictions were applied.

SELECTION CRITERIA

Randomized controlled trials and cluster-randomized trials comparing enhanced external counterpulsation therapy to sham treatment in adults, aged over 18 years, with chronic stable and stable refractory angina pectoris graded Canadian Cardiovascular Society Class III to IV at baseline.

DATA COLLECTION AND ANALYSIS

Two authors independently screened papers, extracted trial details and assessed risk of bias.

MAIN RESULTS

One trial (139 participants) was included in this review. Poor methodological quality, in terms of trial design and conduct, incompleteness in reporting of the review's primary outcome, limited follow up for the secondary outcomes and subsequent flawed statistical analysis, compromised the reliability of the reported data.

AUTHORS' CONCLUSIONS

We found one relevant trial which failed to address the characteristics of interest satisfactorily, in terms of severity of angina, for the participants in this review. Participants with the most severe symptoms of angina were excluded, therefore the results of this study represent only a subsection of the broader population with the disorder, are not generalizable and provide inconclusive evidence for the effectiveness of enhanced external counterpulsation therapy for chronic angina pectoris.

Residual high-grade angina after enhanced external counterpulsation therapy

OBJECTIVE

We evaluated the degree of residual angina on the outcomes of enhanced external counterpulsation (EECP) therapy for chronic stable angina.

BACKGROUND

Angina refractory to medical therapy is common in the pool of patients who are not completely revascularized by angioplasty or bypass surgery.

METHODS

We examined 902 patients enrolled from 1998 to 2001 in the Second International Enhanced External Counterpulsation Patient Registry. Baseline and outcome variables were stratified by the last recorded Canadian Cardiovascular Society class.

RESULTS

Residual Class 3 (12.1%) or 4 (2.3%) angina was uncommon among patients with severe coronary artery disease after treatment with EECP. Prevalence of diabetes, hypertension, dyslipidemia, and heart failure was similar among the anginal post-EECP anginal classes. Multivessel coronary disease was more common in those with higher-grade angina at completion. More frequent and severe angina at entry was more common in those with the higher anginal classes at EECP (P<.001). There were no differences in the rates of chronic medications utilized or prior revascularization. At 3-year follow-up, rates of death, myocardial infarction, percutaneous coronary intervention, and coronary artery bypass surgery tended to be higher across increasing residual angina classes. The composite cardiac event rates were 34%, 33%, and 44% for those with Class 0, Class 1/2, and Class 3/4 angina at EECP completion (P=.01), respectively. Multivariate analysis for the composite endpoint found residual Class 3/4 angina (OR=1.59, 95% CI=1.19-2.17, P=.002), diabetes (OR=1.57, 95% CI=1.23-2.01, P=.0003), age (per decile OR=1.17, 95% CI=1.04-1.31, P=.007), and greater EECP augmentation (OR=0.79, 95% CI=0.65-0.96, P=.02) as significant predictors.

CONCLUSIONS

Residual high-grade angina after EECP occurs in those with more severe angina and multivessel disease at baseline and is associated with cardiac events over the next 3 years. These data suggest that close clinical observation and intensive management of those with high-grade angina post-EECP are warranted.

Effects of enhanced external counterpulsation on anginal symptoms and improvements in objective measures of myocardial ischaemia

BACKGROUND

Enhanced external counterpulsation (EECP) is a novel, potentially beneficial adjunct therapy used for angina pectoris. We assessed the efficacy of this method in relieving angina and improving objective measures of myocardial ischaemia.

METHODS

All patients (67) who referred for EECP to Shahid Chamran Hospital, Isfahan, Iran from 2002 to 2005 were included. Demographic data, coronary artery disease (CAD) risk factors and baseline angiographic data were collected. Anginal symptoms, Canadian Cardiovascular Society (CCS) functional class, echocardiographic parameters (ejection fraction, left ventricular end-diastolic and end-systolic diameters) and exercise test duration before and after the treatment were compared.

RESULTS

Seventy-seven per cent of patients who had undergone EECP had a positive clinical response. Exercise test duration and CCS functional class improved after the treatment. However, EECP had no significant effect on echocardiographic parameters. Efficacy was independent of age, gender, CAD risk factors, prior CCS functional class and echocardiographic parameters. Patients without left main artery involvement and those who had at least one non-obstructed artery demonstrated a greater likelihood of improvement.

CONCLUSION

The results of this study suggested that EECP is a safe, well tolerated, and significantly effective treatment for angina pectoris.

Novel therapeutic approaches to treating chronic angina in the setting of chronic ischemic heart disease

Pharmacologic therapy to alleviate symptoms in chronic angina has been enhanced by the recent approval of several novel compounds that complement the traditional approach using beta-adrenergic blocking drugs, calcium antagonists, and long-acting nitrates. In the United States, ranolazine, a drug that inhibits late I(Na), was approved for patients with chronic angina that remain symptomatic on beta-blockers, calcium antagonists, or long-acting nitrates, on the basis of an acceptable safety profile and efficacy in several randomized placebo controlled studies. A slight increase in the QT interval is observed (<10 ms on average) at the maximum approved dose of 1,000 mg twice daily. Therefore, an ECG should be acquired at baseline and during follow-up, and the drug should not be used in patients with QT prolongation or those who are on QT prolonging drugs unless longer term randomized outcome data demonstrates no excess risk. The MERLIN trial of non-ST-elevation acute coronary syndrome (NSTE ACS) randomized 6,560 patients to assess the potential benefit of ranolazine in reducing the composite endpoint of cardiovascular death, myocardial infarction, and recurrent ischemia, with results expected in 2007. In Europe, ivabradine, a drug that inhibits the hyperpolarization-activated mixed sodium/potassium inward I(f) current, which slows the rest and exercise heart rate, was approved in 2005. Ivabradine at a dose of 10 mg twice daily has been shown to have similar efficacy to amlodipine 10 mg once daily or atenolol 100 mg once daily in alleviating chronic angina symptoms. In this review, several other novel investigational approaches are presented and patient selection considerations for the most recent approved drugs for chronic angina are discussed.

Biomechanopharmacology: a new borderline discipline

Flowing blood is more than a drug transporter in pharmacology; its mechanical impact should also be considered. The in vitro pharmacological dose-response pattern of endothelial cellular functions can be significantly modified by in vivo shear stress. A new borderline discipline, biomechanopharmacology, is forming at the boundary between biomechanics and pharmacology. Biomechanopharmacology will probably consist of both the pharmacological intervention of signals induced by biomechanical factors and the biomechanical influence on pharmacokinetics and pharmacodynamics, in addition to the joint effect of biomechanical and pharmacological factors. Recent investigations show that exercise enhances the shear of pulsatile blood flow to stimulate angiogenesis. The benefits of exercise for gaining joint biomechanical and pharmacological effects should be emphasized.