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PubMed1998

Prior revascularization increases the effectiveness of enhanced external counterpulsation.

BACKGROUND AND HYPOTHESIS: Enhanced external counterpulsation (EECP) is an effective noninvasive treatment for chronic angina. However, its usefulness has been felt to be limited in patients with angiographically demonstrated triple-vessel coronary artery disease (CAD), in accord with the hypothesis that a patent vessel is necessary for transmission of the EECP-augmented coronary artery pressure and volume to the distal coronary vasculature. METHODS: The effect of revascularization [coronary artery bypass grafting (CABG)] prior to EECP was examined in 60 patients with CAD and chronic angina (35 without and 25 with prior CABG). Patients were grouped by the extent of CAD (single-, double-, triple-vessel disease in the unrevascularized group) and by the extent of residual disease (number of stenotic native vessels unbypassed or supplied by a stenotic graft in the CABG group). Significant CAD or graft stenoses were defined as stenoses demonstrating > or = 70% luminal diameter narrowing. Benefit was assessed by improvement in post-EECP treatment over pretreatment radionuclide stress testing. RESULTS: Radionuclide stress testing demonstrated a comparable favorable response (80 vs. 71%; p = NS) in patients with prior CABG versus unrevascularized patients. Enhanced external counterpulsation was highly and comparably effective in patients with unrevascularized native single- and double-vessel CAD and in patients with CABG with residual single- and double-vessel CAD (88 vs. 80%; p = NS). Most notably, CABG significantly increased the beneficial response to EECP in those patients with triple-vessel CAD and stenotic grafts compared with unrevascularized patients with triple-vessel CAD (80 vs. 22%; p < 0.05 by chi-square test). CONCLUSION: The results suggest a new role for EECP as an effective treatment for post CABG ischemia, despite extensive CAD and even in the presence of stenotic grafts.

Aged↗

PubMed2004

Effectiveness of enhanced external counterpulsation in patients with left main disease and angina.

BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive device that uses three pairs of sequentially inflated pneumatic cuffs applied to the lower extremities and synchronized with the heart beat to provide diastolic augmentation, increase coronary blood pressure and flow, venous return and cardiac output, and decrease afterload. HYPOTHESIS: This study examines the safety and effectiveness of EECP therapy in patients with significant left main coronary artery disease (LMD). METHODS: In all, 2,861 patients enrolled in the International EECP Patient Registry (IEPR) were divided into three groups, those without LMD (n = 2,377), those with LMD and prior CABG (n = 431), and those with unbypassed LMD (n = 53). RESULTS: Patients with LMD, with or without prior CABG, were significantly more likely to have triple-vessel disease (98.1 and 88.7%, respectively) than patients without LMD (41.9%). Post-EECP, 74% without LMD, 75% with LMD with prior CABG, and 65% with unbypassed LMD improved their Canadian Cardiovascular Society (CCS) angina by at least one class (p = NS). There were no differences in the mean decrease in weekly angina episodes (7.1 vs. 8.0 vs. 7.6) and in the mean frequency of weekly nitroglycerin use (6.6 vs. 8.1 vs. 8.9). At 6-month follow-up, the CCS class improved further in all three groups, and there was a further reduction in mean weekly angina episodes (4.7 vs. 4.6 vs. 5.3) and nitroglycerin use (6.5 vs. 6.8 vs. 8.2). Kaplan-Meier life table analysis 8 months after starting EECP demonstrated a major cardiovascular event rate of 11.2% in patients without LMD, 15.6% in LMD with CABG, and 24.3% in LMD without prior CABG. Late mortality in unbypassed LMD was 13.2% (confidence interval [CI] 3.3-23.1) versus 4.8% (CI 2.7-7.1) in LMD with CABG, and 2.8% (CI 2.1-3.5) without LMD (p = 0.0039 by log-rank test). CONCLUSION: Enhanced external counterpulsation is equally effective in relieving angina in patients with or without LMD. However, the significantly increased late mortality in patients with LMD without prior CABG suggests that early revascularization should be considered in these patients.

Aged↗

PubMed2004

Enhanced external counterpulsation does not alter arterial stiffness in patients with angina.

BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive treatment for angina that acutely augments diastolic pressure and reduces cardiac afterload. However, the mechanism of the sustained clinical benefit seen with this therapy is not known. HYPOTHESIS: The study aimed to determine whether EECP leads to an improvement in arterial stiffness. METHODS: In all, 22 men and 1 woman with angina (age 63.6 +/- 6.7 years, mean +/- SD) were studied prior to and after 35 h of EECP therapy over 7 weeks. We measured carotid-radial (C-R) pulse wave velocity (PWV), and aortic augmentation index (AI) was derived from radial and carotid artery waveforms using applanation tonometry. Seventeen patients underwent treadmill exercise testing before and after the 7 weeks of EECP. RESULTS: After EECP therapy, despite a significant improvement in treadmill exercise time and a reduction in systolic and diastolic blood pressures, there was no significant change in any arterial stiffness parameters: Mean C-R PWV was 8.4 +/- 0.8 m/s at baseline and 8.0 +/- 1.2 m/s after 7 weeks of EECP, mean change: -0.4, 95% confidence interval (CI): -1.0, + 0.2, p = 0.17. Mean radial-derived AI was 25.7 +/- 10.4% before and 24.6 +/- 10.8% after, mean change: +1.1%, 95% CI: -2.3, +4.5, p = 0.53. Median AI-carotid was 31.5% before and 28.7% after; median change: -0.5, interquartile range: -9.5, +3.5, p = 0.32. Nineteen patients returned for 6-month recordings; neither blood pressure nor arterial stiffness readings were significantly different from baseline. CONCLUSION: Enhanced external counterpulsation therapy does not significantly alter arterial stiffness. Other than an initial reduction in blood pressure, the sustained clinical benefit seen with this therapy is unlikely to be effected through alterations in arterial wall mechanical properties.

Aged↗

PubMed2003

Superior performance of a paraaortic counterpulsation device compared to the intraaortic balloon pump.

The purpose of this study was to compare the hemodynamic effectiveness of a 30-ml stroke volume paraaortic counterpulsation device (PACD), presenting the advantages of ease of implantation and driving by a standard intraaortic balloon pump (IABP) console (Datascope 96, Datascope Corp., Montvale, NJ, USA) to that of a 40-ml IABP, in the setting of experimental heart failure. In an acute heart failure model, the IABP was placed in the descending aorta and the PACD in the ascending aorta of eight pigs. Both devices were driven by the same system, and hemodynamic measurements were obtained with and without mechanical assistance. The two pumps significantly reduced the systolic and end-diastolic aortic pressures, but the PACD reduced the latter more effectively (42.6 +/- 18.1% vs 11.0 +/- 9.9%, p = 0.0001). Both pumps provided significant aortic diastolic augmentation, but the counterpulsation wave of the PACD was significantly greater (augmentation of 44.8 +/- 22.2% vs 37.6 +/- 15.6%, p = 0.031). Both lowered the end-diastolic left ventricular pressure with a trend toward PACD superiority (24.2 +/- 13.7% vs 19.7 +/- 13.5%, p = 0.064). It is concluded that the PACD, even with smaller stroke volume, is more effective than the IABP. The simplicity of its implantation, together with the ability of the standard IABP consoles to control its function, make it a promising device for mechanical assistance of the failing heart.

Animals↗

PubMedDate not supplied

High stroke volume para-aortic counterpulsation device versus centrifugal pump in cardiogenic shock: experimental study.

During the last decades a number of left ventricular assist devices has been used especially for patients resistant to pharmacologic treatment and to intraaortic balloon pump (IABP) support for left ventricular failure. A high stroke volume para-aortic counterpulsation device (PACD) has been developed utilizing the principle of the diastolic counterpulsation technique. In this study the hemodynamic effects of the valveless PACD were compared to those of the centrifugal blood pump (CBP) in nine dogs in acute experimental cardiogenic shock. Hemodynamic measurements were obtained at baseline with both devices off, PACD on and CBP off, or PACD off and CBP on. There was no difference in mean aortic pressure between PACD on (60.0 +/- 11.5 mmHg) and CBP on (69.0 +/- 26.8 mmHg). Similarly, there was no difference in left ventricular end-diastolic pressure with the PACD on (11.9 +/- 5.4 mmHg) versus the CBP on (9.9 +/- 5.2 mmHg) or the cardiac index with the PACD on (84 +/- 36 ml/kg/min) versus the CBP on (77 +/- 36 ml/kg/min). However, the left ventricular systolic pressure (55.0 +/- 19.0 with PACD versus 73.0 +/- 26.0 with CBP,p < 0.001), the tension time index (712 +/- 381 versus 1333 +/- 694,p < 0.01), and the double product (5629 +/- 2574 versus 7440 +/- 3294,p < 0.01) were significantly lower during assistance with the PACD than with the CBP. It was concluded that PACD is at least as effective as CBP for restoring hemodynamic status during acute experimental cardiogenic shock. Moreover, the PACD unloads the left ventricle more effectively than CBP, making it suitable for left ventricular mechanical support in cases with reversible myocardial damage.

Animals↗

PubMed1998

[Pneumatic external counterpulsation--a therapy option in angina pectoris].

Pneumatic external counterpulsation operates by applying ECG-triggered diastolic pressure via cuffs to the vascular bed of the lower limbs. Comparable with intra-aortic balloon pumping, PECP produces a diastolic augmentation combined with increase of mean arterial pressure and coronary perfusion. American, Asian, and our own data demonstrated a reduction of angina pectoris through repeated use of PECP one or two hours daily for four to seven weeks. Exercise testing and thallium scanning confirmed the clinical improvement. PECP is a virtually risk-free treatment option in patients suffering from angina despite medical and interventionell treatment. Opening of collaterals and collateral growth induced by external counterpulsation are discussed as the cause of clinical benefit.

Angina Pectoris↗

PubMed1991

Pulmonary artery balloon counterpulsation for intraoperative right ventricular failure.

Two cases of severe low cardiac output and right ventricular failure after coronary artery bypass grafting necessitated pulmonary artery balloon counterpulsation after intraaortic balloon pumping and maximal inotropic/pressor support were unsuccessful in maintaining a satisfactory cardiac output. Hemodynamic improvement was sufficient to allow removal of the device 2 and 3 days postoperatively, with survival in 1 patient. Pulmonary artery counterpulsation is less morbid in comparison with other mechanical methods of right ventricular support and is applicable in right ventricular failure of intermediate severity.

Aged↗

PubMed1994

A simulation study of external counterpulsation.

To study the haemodynamic effect of external counterpulsation, a computer model has been extended based on our previous work. Using this model, computer simulations have been performed on following aspects: the relationship between blood flow distributions and the control scheme; counterpulsation with and without buttock balloons; effects of duration and time intervals for sequential pulsing; and the potential to use a performance index for the optimal control of this assist device to the failing heart. The results indicate that effective assistance can be achieved by a proper setting of the control scheme. The results also show that this device is effective to improve the circulation status of other organs in addition to the heart. Simulation results agree well with the clinical data.

Abdomen↗

PubMed1991

Effect of intra-aortic balloon counterpulsation on right-left shunt following right ventricular infarction.

Intra-aortic balloon counterpulsations decrease the left ventricular end-diastolic pressure and, subsequently, the left atrial pressure in patients with impaired myocardial function following myocardial infarction. This paper reports a case of right ventricular infarction in a patient with patency of the oval foramen where the use of intra-aortic balloon counterpulsation led to the perpetuation of the right-to-left shunt.

Coronary Artery Bypass↗

PubMed2004

Two-year outcomes after enhanced external counterpulsation for stable angina pectoris (from the International EECP Patient Registry [IEPR]).

We assessed the long-term outcomes of enhanced external counterpulsation in relieving angina and improving the quality of life in a large cohort of patients with chronic angina pectoris. Seventy-three percent had a reduction by > or =1 angina class at the end of treatment, and 50% reported an improvement in the quality-of-life assessment after enhanced external counterpulsation; these results were sustained at 2-year follow-up.

Adult↗

PubMed2006

Cyclic GMP release by acute enhanced external counterpulsation.

BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive, pneumatic technique that provides favorable effects in patients with coronary artery disease and heart failure. The mechanisms by which EECP exerts its beneficial effects remain poorly understood. Cyclic GMP (cGMP) regulates vascular smooth muscle tone that may improve arterial function. We investigated the effect of a single session of EECP on plasma and platelet cGMP in asymptomatic subjects with cardiovascular risk factors (HCVR) and in patients with coronary artery disease (CAD). METHODS: Fifty-five subjects were included (25 HCVR and 30 CAD) and randomized into two groups to receive either sham (control) or active EECP during 1 h. Plasma and platelet cGMP were measured immediately before and after EECP by radioimmunoassay. RESULTS: One hour of EECP increased cGMP plasma concentration by 52% +/- 66% (SD) (P < .001) and platelet content by 19% +/- 28% (P < .01). The increase in plasma cGMP was particularly marked in CAD patients receiving active EECP (P < .01), mainly in those with low LDL-cholesterol. Platelets, inhibition of nitric oxide synthesis by N(G)-monomethyl-l-arginine (L-NMMA) reduced cGMP by 23% +/- 31% (P < .001), whereas presence of superoxide dismutase and inhibition of phosphodiesterase-5 increased cGMP by 46% +/- 49% and 70% +/- 77%, respectively (P < .001). In all of the cases EECP increased additional platelet cGMP content, which suggests nitric oxide synthase activation. CONCLUSIONS: Acute external counterpulsation showed that very early treatment increases the cGMP production that may participate in the mechanism by which EECP exerts its clinical benefit. Analysis of the modulation of platelet cGMP content suggests that EECP activated the nitric oxide-dependent pathways.

Cholesterol, LDL↗

PubMed2005

A simple method of triggering balloon counterpulsation accurately during off-pump coronary artery bypass surgery.

With increasing experience, off-pump coronary artery bypass grafting for high-risk patients can be performed safely. However, in patients who need intraaortic balloon counterpulsation support, mistriggering of intraaortic balloon counterpulsation during mobilization of the heart can induce unstable hemodynamic conditions. My colleagues and I have developed a simple method of detecting the trigger signal accurately: an epicardial pacemaker wire is placed close to the apex of the left ventricle, and 1 precordial V lead is disconnected and then linked to the epicardial pacemaker wire. This method provides an excellent detection of R-wave potentials in any position of the heart throughout an entire off-pump coronary artery bypass grafting procedure.

Coronary Artery Bypass, Off-Pump↗

PubMed2004

Muscular counterpulsation: preliminary results of a non-invasive alternative to intra-aortic balloon pump.

OBJECTIVES: IABP is the most widely used form of temporary cardiac assist and its benefits are well established. We designed an animal study to evaluate a device based on muscular counterpulsation (MCP) that should reproduce the same hemodynamic effects as IABP in a completely non-invasive way. METHODS: Six calves, 60+/-4 kg, divided into 2 groups, in general anaesthesia, equipped with EKG, Swan-Ganz, pressure probe in the femoral artery and flow probe in the left carotid artery, received either IABP through right femoral artery, or muscle counterpulsation (MCP). MCP consists of electrically induced skeletal muscle contraction during early diastole, triggered by EKG and microprocessor controlled by a portable device. For each animal the following parameters were also considered: mean aortic pressure (mAoP), CO, CI, left ventricular stroke work index (LVSWI), systemic vascular resistance (SVR) and mean femoral artery flow (Faf). We did 3 sets of measurements: baseline (BL), after 20 (M20) and 40 (M40) min of cardiac assistance. These measurements have been repeated after 40 min of rest for 3 times. Results are expressed as mean+/-SD. RESULTS: Baseline values: mAoP, 76.51+/-12 mmHg; mCVP, 11.5+/-3 mmHg; CO, 5+/-1 l/min per m(2); LVSWI, 0.77+/-0.2 KJ/m(2); SVR, 1040+/-15 dyns/cm(-5); Faf, 75.5+/-10 ml/min. IABP group: mAoP, 81.1+/-6 mmHg; mCVP, 1+/-0.1 mmHg; CO, 4.5+/-0.7 l/min per m(2); LVSWI, 0.69+/-0.2 KJ/m(2); SVR, 1424+/-8 dyns/cm(-5); Faf, 64.3+/-3 ml/min. MCP group: mAoP, 60.1+/-7 mmHg; mCVP, 23.6+/-2 mmHg; CO, 4.8+/-0.4 l/min per m(2); LVSWI, 0.69+/-0.2 KJ/m(2); SVR, 608+/-25 dyns/cm(-5); Faf, 92.3+/-12 ml/min. CONCLUSIONS: MCP and IABP had the same effects on CO and LVSWI. Moreover, MCP reduced SVR and increased the peripheral circulation without requiring any vascular access nor anticoagulation therapy.

Animals↗

PubMed2005

Synchronously counterpulsating extracorporeal life support enhances myocardial working conditions regardless of systemic perfusion pressure.

OBJECTIVE: A new pulsatile extracorporeal life support (pECLS) system has entered the market. We wanted to investigate what potential advantages pECLS may have over current non-pulsatile systems (NPS). Our research was focused on the pump's functional interaction with the left ventricle and the coronary circulation. METHODS: Extensive hemodynamic measurements were performed during asynchronous and synchronous pECLS in 10 calves. The two extremes regarding LV afterload, namely systolic arrival (SA) and diastolic arrival (DA) of the pump pulse were studied. RESULTS: SA was associated with increased oxygen consumption (+57%) and decreased diastolic coronary perfusion (-43%). DA increased left ventricular output (DA: 4.5+/-2.4 l/min vs SA: 3.5+/-2.2 l/min), LV ejection fraction (+10%), and ventricular efficiency (+17%). Mean aortic pressure and mean coronary flow were only marginally affected by pulse incidence. Systolic impairment was more pronounced with higher bypass flows. These results indicate that myocardial working conditions can be optimized by phasing pECLS ejection into cardiac diastole. CONCLUSION: We conclude that during pECLS, myocardial working conditions can be improved by avoidance of systolic impairment. Synchronously counterpulsating pECLS could be a more economic and versatile alternative to NPS or NPS combined with intra-aortic balloon pumping. The potential benefits of synchronously counterpulsating pECLS over the current alternatives remain to be investigated.

Animals↗

PubMed2004

Reduction of "no-reflow" phenomenon by intra-aortic balloon counterpulsation in a randomized magnetic resonance imaging experimental study.

OBJECTIVES: Intra-aortic balloon counterpulsation (IABC) can improve post-myocardial infarction (MI) outcomes, but the mechanisms of such effect remain unclear. We hypothesized that IABC augmentation reduces the extent of microvascular obstruction after acute infarction. BACKGROUND: Microvascular obstruction or "no-reflow" (MO) has been shown to negatively influence left ventricular (LV) remodeling after myocardial infarction (MI). METHODS: Seventeen dogs underwent 90 min of coronary artery occlusion followed by reperfusion. Animals were then randomized to either IABC (n = 9) or control (n = 8); IABC augmentation was performed for 24 h after MI. Microvascular obstruction and infarct size by first-pass and delayed contrast-enhanced magnetic resonance imaging (MRI) were measured at 1 and 24 h after reperfusion and compared with postmortem infarct size and MO by microspheres. RESULTS: Microvascular obstruction by MRI, expressed as percent LV mass, decreased significantly in IABC (4.9 +/- 2.2% to 3.6 +/- 1.5%) and increased in controls (3.4 +/- 0.5% to 4.9 +/- 1.1% from 1 to 24 h, respectively; p < 0.001). Similar results were found for MO defined by microspheres. In the control group, MO increased significantly, during 24 h of study (from 8.8 +/- 1.7% to 43.2 +/- 11.1% of infarcted myocardium; p < 0.05), whereas not important change was observed in the IABC group (from 21.3 +/- 7.1% to 25.8 +/- 14.7%; p < 0.05 vs. control at 24 h). Infarct size, measured by MRI, increased in both groups (13.2 +/- 1.8 to 15.5 +/- 2.1 from 1 to 24 h, respectively; p < 0.05). CONCLUSIONS: Intra-aortic balloon counterpulsation augmentation performed after reperfusion improves myocardial perfusion at the tissue level, and reduces the extent of no-reflow caused by microvascular obstruction.

Animals↗

PubMedDate not supplied

Enhanced external counterpulsation for the treatment of angina pectoris.

The treatment of refractory chronic angina pectoris presents an increasing problem for all physicians caring for patients with coronary artery disease because of the large number of individuals who have either failed multiple revascularization procedures or are not appropriate candidates for such procedures. The aim of this study was to review the safety, efficacy, and clinical applicability of a noninvasive technique (external counterpulsation) for the treatment of angina pectoris. A MEDLINE search for all English language abstracts, meeting presentations, journal articles, and reviews from 1960 through December 2005 was conducted. Of the 194 citations in the literature, 60 appeared before 1983 when the enhanced version of the technique (the one that is presently used) was first reported. Criteria for further evaluation of the 134 post-1983 citations were either (1) randomized trial, (2) observational study of at least 10 patients, or (3) investigations into possible mechanisms. Of the 134 citations, 45 were used for data extraction. Observational studies from the United States, Asia, and Europe have demonstrated improvement in symptoms, reduction in anginal episodes, better quality of life, and improved exercise performance in over 5000 patients. The only randomized study (Multicenter Study of Enhanced External Counterpulsation) confirmed these findings as well as the continuation of clinical benefits at least 1 year posttreatment. Although the mechanisms by which diastolic augmentation achieves these beneficial results are still under investigation, this is a promising noninvasive therapy in a group of patients with limited treatment options.

Angina Pectoris↗

PubMed2003

Enhanced External Counterpulsation for the relief of angina in patients with diabetes: safety, efficacy and 1-year clinical outcomes.

BACKGROUND: Patients with diabetes are at greater risk for coronary events, yet they are less likely to benefit from revascularization than those without diabetes. Enhanced external counterpulsation has recently emerged as a treatment option for select patients with chronic stable angina. METHODS: We examined baseline characteristics, angina response, and cardiac outcomes of patients with diabetes mellitus treated with Enhanced External Counterpulsation (EECP) for chronic stable angina. Data were collected from patients enrolled in the International EECP Patient Registry (IEPR) before and after a course of EECP, and at 1 year after completion of treatment. RESULTS: Of 1532 IEPR patients studied, 43% had diabetes mellitus at baseline. Patients with diabetes were experiencing, on average, 11 episodes of angina per week. Most had been revascularized with prior percutaneous coronary intervention or coronary artery bypass graft surgery (86%) and most were considered unsuitable for either additional procedure (87%). Treatment was completed as prescribed in 79% of patients (mean, 32 hours). Immediately after EECP, 69% of patients with diabetes demonstrated a reduction in angina of > or =1 Canadian Cardiovascular Society angina class. After 1 year, maintenance of angina reduction was reported in 72% of patients with diabetes. Quality of life was significantly improved. Despite a high-risk profile among the diabetic group in this study, 1-year mortality was similar to coronary intervention registry populations. CONCLUSION: This study suggests that in select patients with diabetes, EECP can be a safe, effective, well-tolerated treatment option for the relief of angina.

Aged↗

PubMed2003

Enhanced external counterpulsation for ischemic heart disease: what's behind the curtain?

Enhanced external counterpulsation (EECP) has been shown to reduce angina and to improve objective measures of myocardial ischemia in patients with refractory angina. Prospective clinical studies and large treatment registries suggest that a course of EECP is associated with prolongation of the time to exercise-induced ST-segment depression and resolution of myocardial perfusion defects, as well as with enhanced exercise tolerance and quality of life. With a growing knowledge base supporting the safety and beneficial clinical effects associated with EECP, this therapy can be considered a valuable treatment option, particularly in patients who have exhausted traditional revascularization methods and yet remain symptomatic despite optimal medical care. However, although the concept of external counterpulsation was introduced almost four decades ago, and despite growing evidence supporting the clinical benefit and safety of this therapeutic modality, little is firmly established regarding the mechanisms responsible for the beneficial effects associated with this technique. Suggested mechanisms contributing to the clinical benefit of EECP include improvement in endothelial function, promotion of coronary collateralization, enhancement of ventricular function, peripheral effects similar to those observed with regular physical exercise, and nonspecific placebo effects. This review summarizes the current evidence for a contribution of these mechanisms to the clinical benefit associated with EECP.

Counterpulsation↗