Does enhanced external counterpulsation reduce symptoms of chronic and refractory angina pectoris?

Angina pectoris is a form of cardiovascular disease.   Symptoms include episodic tightness in the chest accompanied by pain in the jaw, back, shoulder or arm and normally last for between 1 to 5 minutes.  Angina is classified according to its severity and may be treated with drugs, lifestyle modifications, education and counselling.  Refractory angina is a form of angina that does not respond well to conventional treatments and patients experience limitations in their ability to undertake physical activity. 

Enhanced external counterpulsation is a treatment that involves placing cuffs around the legs of a patient, which when inflated assist blood to return to the heart and as the cuffs deflate allow blood vessels to return to normal.  It is believed that this treatment may alleviate some of the symptoms of angina.  Treatment consists of one hour daily sessions for a period of up to seven weeks and is performed in a medically supervised environment.

This review studied the effectiveness and safety of enhanced external counterpulsation in improving health outcomes for patients aged 18 years or over with chronic stable and refractory angina (graded Canadian Cardiovascular Society angina class III to IV).  The review compared outcomes in patients treated with enhanced external pulsation to patients treated with a sham treatment.  Searches found over 300 potentially eligible studies however only one study met most of the inclusion criteria.  The study used in the review involved 139 participants in the United States.  Participants in the study were treated with hour long sessions, either once or twice daily of active enhanced external counterpulsation or inactive enhanced external counterpulsation (sham).  Limited data was available on the health related outcomes of patients participating in the study; however health related quality of life outcomes were larger in the enhanced external counterpulsation patients than patients receiving the inactive (sham) treatment; but the improvement was only significant in three of nine parameters.  Angina pain counts decreased in the patients receiving enhanced external counterpulsation and this result was statistically significant

55% of patients receiving treatment reported adverse events compared to 26% in the control group with approximately half of these events considered as device-related.  Adverse events reported included leg and back pain and skin abrasions. 

The review found that there is a lack of reliable and conclusive evidence that enhanced external counterpulsation can improve symptoms of angina in patients with chronic stable or refractory forms of the condition.

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.

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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.

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