Category: Research

This post is an excerpt from an article originally published in 2012 by the National Library of Medicine. Click the link at the bottom to read the full article.

Improved pharmacological, invasive, and surgical therapies for cardiovascular diseases over the last few decades have led to an increase in life expectancy of individuals with angina.

Despite treatment with multiple medications and invasive procedures, these patients remain symptomatic and functionally limited. Enhanced external counterpulsation (EECP) is a safe, noninvasive, well-tolerated, and clinically effective outpatient physical therapy for many patients with refractory angina. Numerous trials demonstrate positive clinical responses to EECP, including reductions in angina and nitrate use, increase in exercise tolerance, and enhanced quality of life. Several mechanisms are thought responsible for the clinical benefits of this therapy. Despite the marked success rates EECP achieves, the treatment remains largely unknown. This review will summarize the current evidence for the use of EECP and spark a better understanding of the potential role of this treatment.

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This post is an excerpt from an article originally published in 2012 by the National Library of Medicine. Click the link at the bottom to read the full article.

Clinical effects of enhanced external counterpulsation treatment in patients with ischemic heart failure

Objective: Enhanced external counterpulsation (EECP) is a noninvasive treatment that is proven safe and effective in patients with coronary artery disease (CAD) and heart failure (HF). The aims of this study are to investigate the clinical effects of EECP therapy in patients with symptomatic CAD and chronic HF, and to find out an answer to the question: Does EECP therapy have any effect on the prognostic markers of HF?

Methods: This study was designed as a prospective cohort study. A total of 68 consecutive patients with symptomatic CAD and chronic HF referred to EECP therapy were enrolled in this study between November 2007 and December 2010; 47 patients (39 males and 8 females, 65 ± 7, years), have undergone EECP treatment, and 21 patients (20 males and 1 female, 62 ± 10 years), who did not want to participate in the EECP program comprised the control group. Statistical analysis was performed using t tests for dependent and independent samples, Mann-Whitney U test, Chi-square and Fischer exact tests.

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This post is an excerpt from an article originally published in 2011 by the American Journal of Cardiology. Click the link at the bottom to read the full article.

Effects of enhanced external counterpulsation on arterial stiffness and myocardial oxygen demand in patients with chronic angina pectoris

Enhanced external counterpulsation (EECP) is a noninvasive technique for treatment of symptomatic coronary artery disease in patients not amenable to revascularization procedures. However, the mechanisms underlying the benefits of EECP remain unknown.

We hypothesized that decreases in arterial stiffness and aortic wave reflection are a therapeutic target for EECP. Patients with coronary artery disease and chronic angina pectoris were randomized (2:1 ratio) to 35 1-hour sessions of EECP (n = 28) or sham EECP (n = 14). Central and peripheral arterial pulse-wave velocity and aortic wave reflection (augmentation index) were measured using applanation tonometry before, and after 17 and 35 1-hour treatment sessions. Wasted left ventricular pressure energy and aortic systolic tension-time index, markers of left-ventricular myocardial oxygen demand, were derived from the synthesized aortic pressure wave. Exercise duration, anginal threshold, and peak oxygen consumption were measured using a graded treadmill test. Central arterial stiffness and augmentation index were decreased after 17 and 35 sessions in the treatment group. Measurements of peripheral arterial stiffness were decreased after 35 sessions in the treatment group. Changes in aortic pressure wave reflection resulted in decreased measurements of myocardial oxygen demand and wasted left ventricular energy. No changes in central or peripheral arterial stiffness were observed in the sham group. Furthermore, measurements of exercise capacity were improved in the EECP group but unchanged in the sham group. In conclusion, EECP therapy decreases central and peripheral arterial stiffness, which may explain improvements in myocardial oxygen demand in patients with chronic angina pectoris after treatment.

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This post is an excerpt from randomized study originally circulated in 2010. Click the link at the bottom to read the full article.

Enhanced external counterpulsation improves peripheral artery flow-mediated dilation in patients with chronic angina: a randomized sham-controlled study

Background: Mechanisms responsible for anti-ischemic benefits of enhanced external counterpulsation (EECP) remain unknown. This was the first randomized sham-controlled study to investigate the extracardiac effects of EECP on peripheral artery flow-mediated dilation.

Methods and results: Forty-two symptomatic patients with coronary artery disease were randomized (2:1 ratio) to thirty-five 1-hour sessions of either EECP (n=28) or sham EECP (n=14). Flow-mediated dilation of the brachial and femoral arteries was performed with the use of ultrasound. Plasma levels of nitrate and nitrite, 6-keto-prostaglandin F(1α), endothelin-1, asymmetrical dimethylarginine, tumor necrosis factor-α, monocyte chemoattractant protein-1, soluble vascular cell adhesion molecule, high-sensitivity C-reactive protein, and 8-isoprostane were measured. EECP increased brachial (+51% versus +2%) and femoral (+30% versus +3%) artery flow-mediated dilation, the nitric oxide turnover/production markers nitrate and nitrite (+36% versus +2%), and 6-keto-prostaglandin F(1α) (+71% versus +1%), whereas it decreased endothelin-1 (-25% versus +5%) and the nitric oxide synthase inhibitor asymmetrical dimethylarginine (-28% versus +0.2%) in treatment versus sham groups, respectively (all P<0.05). EECP decreased the proinflammatory cytokines tumor necrosis factor-α (-16% versus +12%), monocyte chemoattractant protein-1 (-13% versus +0.2%), soluble vascular cell adhesion molecule-1 (-6% versus +1%), high-sensitivity C-reactive protein (-32% versus +5%), and the lipid peroxidation marker 8-isoprostane (-21% versus +1.3%) in treatment versus sham groups, respectively (all P<0.05). EECP reduced angina classification (-62% versus 0%; P<0.001) in treatment versus sham groups, respectively.

Conclusions: Our findings provide novel mechanistic evidence that EECP has a beneficial effect on peripheral artery flow-mediated dilation and endothelial-derived vasoactive agents in patients with symptomatic coronary artery disease.

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This post is an excerpt from an article originally published in 2010 by the J Pak Med Association. Click the link at the bottom to read the full article.

Enhanced external counterpulsation (EECP) for refractory angina pectoris (RAP): results from a first case series

Enhanced External Counterpulsation (EECP) has emerged as a promising non-invasive modality not only for patients with refractory angina pectoris (RAP) but also for patients with heart failure.

To our knowledge, no published data exists in Pakistan about the benefits of EECP. We report on a case series of 16 consecutive patients undergoing EECP. All patients were either deemed not to be candidates for revascularization or had failed revascularization with RAP on optimal medical therapy. Data was collected regarding the coronary anatomy, clinical presentation, Pre and Post EECP Canadian Cardiovascular Society (CCS) class, nitrate use and 6-min walk test. Patients with severe peripheral vascular disease and arrhythmias were excluded. The mean age was 56 +/- 11.1 years. Eight patients had 3-vessel disease. 4 post-CABG with occluded grafts and the rest with variable combination of coronary disease. Seven (44%) patients had Unstable Angina and 9 (56%) had Stable Angina. The mean 6 min walk distance before EECP was 295 +/- 148.60 meters and after EECP was 360 +/- 102.12 meters (p = 0.013). The CCS class before and after EECP also showed significant improvement (p = 0.017). Sublingual nitroglycerine use also showed a positive trend after EECP. EECP was noted to be a safe and effective modality for patients with RAP with statistically significant improvement in measures of quality of life.

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This post contains excerpts from an article originally published in 2010 by the Pharmacotherapy. Click the link at the bottom to read the full article.

Impact of enhanced external counterpulsation on Canadian Cardiovascular Society angina class in patients with chronic stable angina

Study objective: To evaluate the true magnitude of benefit from enhanced external counterpulsation (EECP) by determining the effect of EECP on Canadian Cardiovascular Society (CCS) angina class in patients with chronic stable angina.

Design: Meta-analysis of 13 prospective studies that evaluated patients with stable angina and reported adequate data on CCS angina class.

Patients: A total of 949 adult patients with stable angina who underwent EECP treatment.

Measurements and main results: A systematic literature search of studies published between 1950 and February 2009 was performed.

Studies were included for meta-analysis if they were reported in the English language, included human subjects, had a prospective study design, and reported adequate data on CCS angina class. The EECP treatment consisted of 35 sessions-1 hour/day, 5 days/week, for 7 weeks. Improvement in angina class was reported as the weighted proportion of patients improving by at least one CCS class from before to after EECP treatment. Heterogeneity was assessed by performing subgroup analyses and using the Cochran Q statistic. Publication bias was assessed by inspection of funnel plots and the Egger bias statistic. Among the 13 studies incorporating 949 patients, angina class was reduced by at least one CCS score in 86% of the patients (95% confidence interval 82-90%, Q statistic p=0.008]. Inspection of funnel plots showed some asymmetry, but the Egger bias statistic showed no publication bias (p=0.97).

Conclusion: The results of our meta-analysis call for further long-term studies to determine the place of EECP therapy in the management of chronic stable angina. Currently, EECP therapy should be considered for patients with stable angina who are refractory to or not suitable for invasive therapy and/or medical management.

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This post is an excerpt from an article originally published in 2009 by the American Journal of Therapeutics. Click the link at the bottom to read the full article.

Effect of enhanced external counterpulsation on clinical symptoms, quality of life, 6-minute walking distance, and echocardiographic measurements of left ventricular systolic and diastolic function after 35 days of treatment and at 1-year follow up in 47 patients with chronic refractory angina pectoris

In a prospective study, enhanced external counterpulsation (EECP) was performed for 1 hour each day for 35 days in 47 patients, mean age 61 +/- 8 years, with prior coronary revascularization who had chronic refractory angina pectoris despite antianginal drugs and who were not candidates for further coronary revascularization.

Compared with baseline values, EECP significantly improved anginal symptoms, dyspnea on exertion, and quality of life after 35 days of treatment (P < 0.001) and at 1-year follow up (P < 0.001). Compared with the baseline value of 653 +/- 249 feet, EECP significantly improved the 6-minute walking distance to 1025 +/- 234 feet after 35 days of treatment (P < 0.001) and to 1040 +/- 221 feet at 1-year follow up (P < 0.001). However, EECP did not significantly affect left ventricular ejection fraction, left ventricular end-diastolic and end-systolic dimensions, left ventricular end-diastolic and end-systolic volumes, E/A ratio, isovolumic relaxation time, and deceleration time measured by two2-dimensional and Doppler echocardiography.

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This post is an excerpt from an article originally published in 2009 by the National Library of Medicine. Click the link at the bottom to read the full article.

Treatment options for refractory angina pectoris: enhanced external counterpulsation therapy

Refractory angina pectoris, defined as angina refractory to maximal medical therapy and standard coronary revascularization procedures, remains a significant health problem in the United States and the world.

Despite a panoply of recent therapeutic advances, patients with refractory angina pectoris are not adequately treated; therefore, scientists have been investigating new technologies to help these patients. The technique of counterpulsation, studied for almost half a century, is considered a safe, highly beneficial, low-cost, noninvasive treatment for these angina patients and now also for those with heart failure. Recent evidence suggests that enhanced external counterpulsation (EECP) therapy may improve symptoms and decrease long-term morbidity via several mechanisms, including improvement in endothelial function, promotion of collateralization, enhancement of ventricular function, improvement in oxygen consumption (Vo(2)), regression of atherosclerosis, and peripheral “training effects” similar to exercise. Numerous clinical trials in the past two decades have shown EECP therapy to be safe and effective for patients with refractory angina, with a clinical response rate averaging 70% to 80%, which is sustained up to 5 years. This review summarizes the current evidence to support EECP’s use in treating refractory angina pectoris.

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This post is an excerpt from an article originally published in 2010 by the International Journal of Cardiology. Click the link at the bottom to read the full article.

A new treatment modality in management of patients with cardiac syndrome X: enhanced external counterpulsation

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This post is an excerpt from an article originally published in 2007 by the Journal of the American College of Cardiology. Click the link at the bottom to read the full article.

Enhanced external counterpulsation and future directions: step beyond medical management for patients with angina and heart failure

Between 25,000 and 75,000 new cases of angina refractory to maximal medical therapy and standard coronary revascularization procedures are diagnosed each year.

In addition, heart failure also places an enormous burden on the U.S. health care system, with an estimated economic impact ranging from $20 billion to more than $50 billion per year. The technique of counterpulsation, studied for almost one-half century now, is considered a safe, highly beneficial, low-cost, noninvasive treatment for these angina patients, and now for heart failure patients as well. Recent evidence suggests that enhanced external counterpulsation (EECP) therapy may improve symptoms and decrease long-term morbidity via more than 1 mechanism, including improvement in endothelial function, promotion of collateralization, enhancement of ventricular function, improvement in oxygen consumption (VO2), regression of atherosclerosis, and peripheral training effects similar to exercise. Numerous clinical trials in the last 2 decades have shown EECP therapy to be safe and effective for patients with refractory angina with a clinical response rate averaging 70% to 80%, which is sustained up to 5 years. It is not only safe in patients with coexisting heart failure, but also is shown to improve quality of life and exercise capacity and to improve left ventricular function long-term. Interestingly, EECP therapy has been studied for various potential uses other than heart disease, such as restless leg syndrome, sudden deafness, hepatorenal syndrome, erectile dysfunction, and so on. This review summarizes the current evidence for its use in stable angina and heart failure and its future directions.

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