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Enhanced external counterpulsation.

Enhanced external counterpulsation is a noninvasive technique designed to increase myocardial perfusion and reduce cardiac workload in patients with coronary artery disease. Recent trials have documented beneficial hemodynamic effects. Stress testing and radionuclide imaging have demonstrated improvements in functional capacity and myocardial perfusion. This procedure may be the therapeutic choice for patients with severe diffuse disease or in whom repeat revascularization is not possible. The relatively low cost of the technique makes it feasible for patients in developing countries.

Coronary Artery Disease↗

Treatment of inoperable coronary disease and refractory angina: spinal stimulators, epidurals, gene therapy, transmyocardial laser, and counterpulsation.

Intractable angina from refractory coronary disease is a severe form of myocardial ischemia for which revascularization provides no prognostic benefit. Inoperable coronary disease is also accompanied by a "vicious cycle" of myocardial dystrophy from a chronic alteration of the cardiac sympathetic tone and sensitization of damaged cardiac tissues. Several adjunctive treatments have demonstrated efficacy when revascularization is either unsuccessful or contraindicated. Spinal cord stimulation modifies the neurologic input and output of the heart by delivering a very low dose of electrical current to the dorsal columns of the high thoracic spinal cord. Neural fibers then release CGRP and other endogenous peptides to the coronary circulation reducing myocardial oxygen demand and enhancing vasodilation of collaterals to improve the myocardial blood flow of the most diseased regions of the heart. Randomized study has shown the survival data at five years is comparable to bypass for high-risk patients. Transmyocardial laser revascularization creates small channels into ischemic myocardium in an effort to enhance flow though studies have shown no improvement in prognosis over medical therapy alone. Enhanced external counterpulsation uses noninvasive pneumatic compression of the legs to improve diastolic filling of the coronary vessels and promote development of collateral flow. The compressor regimen requires thirty-five hours of therapy over a seven-week treatment period. Therapeutic angiogenesis requires injection of cytokines to promote neovascularization and improve myocardial perfusion into the regions affected by chronic ischemia. Phase 3 trials are pending. High thoracic epidural blockade produces a rapid and potent sympatholysis, coronary vasodilation and reduced myocardial oxygen demand in refractory coronary disease. This technique can be used as an adjunct to bypass surgery or medical therapy in chronic or acute unstable angina. Epidurals are easy to perform and often available for outpatient or inpatient use. The rapid anti-ischemic effect may complement therapeutic angiogenesis or other interventions with delayed onset to clinical benefit. A new era for interventional and implant cardiology is beginning to emerge as more clinicians, including cardiologists, gradually learn new procedures to safely provide more therapeutic options for patients suffering refractory angina.

Anesthesia, Epidural↗

One year follow-up of patients with refractory angina pectoris treated with enhanced external counterpulsation.

BACKGROUND: Enhanced external counterpulsation (EECP) is a non-invasive technique that has been shown to be effective in reducing both angina and myocardial ischemia in patients not responding to medical therapy and without revascularization alternatives. The aim of the present study was to assess the long-term outcome of EECP treatment at a Scandinavian centre, in relieving angina in patients with chronic refractory angina pectoris. METHODS: 55 patients were treated with EECP. Canadian cardiovascular society (CCS) class, antianginal medication and adverse clinical events were collected prior to EECP, at the end of the treatment, and at six and 12 months after EECP treatment. Clinical signs and symptoms were recorded. RESULTS: EECP treatment significantly improved the CCS class in 79 +/- 6% of the patients with chronic angina pectoris (p < 0.001). The reduction in CCS angina class was seen in patients with CCS class III and IV and persisted 12 months after EECP treatment. There was no significant relief in angina in patients with CCS class II prior to EECP treatment. 73 +/- 7% of the patients with a reduction in CCS class after EECP treatment improved one CCS class, and 22 +/- 7% of the patients improved two CCS classes. The improvement of two CCS classes could progress over a six months period and tended to be more prominent in patients with CCS class IV. In accordance with the reduction in CCS classes there was a significant decrease in the weekly nitroglycerin usage (p < 0.05). CONCLUSION: The results from the present study show that EECP is a safe treatment for highly symptomatic patients with refractory angina. The beneficial effects were sustained during a 12-months follow-up period.

Aged↗

Effects of enhanced external counterpulsation on hemodynamics and its mechanism.

BACKGROUND: The hemodynamic effects of enhanced external counterpulsation (EECP) and its mechanism(s) were investigated in relation to neurohumoral factors in patients with acute myocardial infarction (AMI). METHODS AND RESULTS: Twenty-four patients with AMI were studied before, during and after EECP treatment for 60 min. Heart rate (HR), right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP) and cardiac index (CI) were determined. In addition, circulating concentrations of neurohumoral factors were determined at each time point. HR did not change following EECP treatment. However, RAP and PCWP increased significantly and CI was significantly elevated during EECP and thereafter. Blood atrial natriuretic peptide (ANP) concentration was significantly increased 15 and 60 min after the start of EECP treatment, but brain natriuretic peptide (BNP) did not change. Renin, aldosterone and catecholamine concentrations also did not change. CONCLUSION: Treatment with EECP resulted in an increased preload because of increased venous return, and CI was increased thereafter. In patients with AMI, EECP increased blood ANP concentration, but not BNP, which suggests that an increase in ANP without an increase in BNP is an important mechanism for the effects of EECP treatment.

Aged↗

Improvement of regional myocardial and coronary blood flow reserve in a patient treated with enhanced external counterpulsation: evaluation by nitrogen-13 ammonia PET.

Enhanced external counterpulsation (EECP) is a noninvasive treatment for chronic stable angina, which works by recruiting and developing the coronary collateral vessels. Coronary perfusion and coronary flow reserve (CFR) were evaluated by nitrogen-13 (13N) ammonia positron emission tomography (PET) in a patient who had undergone EECP. The patient, who had 3-vessel coronary artery disease, required a percutaneous transluminal coronary angioplasty (PTCA) for the right coronary artery. The PTCA was successful, but 6 months later he again felt chest oppression. The coronary angiography showed re-stenosis at the PTCA site, and other progressive coronary stenosis. The patient was again treated with EECP for 35 h. The 13N-ammonia PET was performed both at baseline and during dipyridamole provocation, before and after EECP treatment. Coronary perfusion of each myocardial wall increased at the baseline (anterior: 0.52-0.75; septal: 0.48-0.66; lateral: 0.61-0.68; inferior: 0.46-0.57 ml min(-1) g(-1), and the CFRs in the septal and inferior walls (septal: 2.07-2.15; inferior: 1.99-2.06) also increased after the treatment. Thus, the EECP treatment improved both coronary perfusion at baseline and CFR, which suggests that it may be one of the choices for treatment of angina.

Ammonia↗

Anticoagulation therapy in intra-aortic balloon counterpulsation: does IABP really need anti-coagulation?

OBJECTIVE: To investigate if intra-aortic balloon pump (IABP) is contraindicated without anticoagulation therapy. METHODS: Some 153 IABP patients in the King Abdulaziz Cardiac Center (KSA) were randomly assigned into two groups. Anticoagulation group (Group A) consisted of 71 patients who were given heparin intravenously with target aPTT 50-70 seconds. Non-anticoagulation group (Group B) consisted of 82 patients without intravenous heparin during balloon pumping. Hematological parameters including platelet count, D-dimer, Plasminogen activator inhibitor-1 (PAI-1) and fibrinogen degradation products (FDP) were checked respectively at the point of baseline, 24 hours, 48 hours and 24 hours post IABP counterpulsation. Clot deposits on balloon surface, vascular complications from IABP including bleeding and limb ischemia were recorded. RESULTS: Platelet count and PAI-1 level decreased at 24 hours and 48 hours in both groups (P<0.05). D-dimer and FDP level increased at 24 hours and 48 hours in both groups (P<0.05), but returned to the baseline level 24 hours post IABP removal (P>0.05). Three patients in Group A and 2 patients in Group B developed minor limb ischemia (P>0.05). No major limb ischemia in either group. Two patients in Group A suffered major bleeding and required blood transfusion or surgical intervention, whereas no patient had major bleeding in Group B. Eight patients had minor bleeding in Group A, but only 2 patients in Group B (P<0.05). No clot deposit developed on IABP surface in either group. CONCLUSION: IABP is safe without routine anticoagulation therapy. Selecting appropriate artery approach and early detection intervention are key methods for preventing complications.

Adult↗

Enhanced external counterpulsation for treatment of refractory angina pectoris.

OBJECTIVE: Enhanced external counterpulsation (EECP) is a noninvasive, well-tolerated treatment, effective for managing patients with refractory angina pectoris. The aim of this study was to evaluate the efficacy of EECP to relieve symptoms, to decrease myocardial ischaemia and to improve cardiac performance in patients with intractable angina, refractory to surgical and medical treatment. METHODS: Twenty-five patients (24 men and one woman, mean age 65 years) with persistent ischaemia notwithstanding optimal medical therapy or after interventional or surgical procedure, received EECP sessions for 35 h. Each patient underwent dobutamine stress echocardiography before and after treatment. We evaluated modifications in either cardiac systolic or diastolic function, and in wall motion score index. RESULTS: Eighty-four percent of patients showed an increase in at least one functional angina class. We did not observe any significant changes in fractional shortening and diastolic function. Thirty-six percent of patients had a reduction in the area of inducible ischaemia at dobutamine stress echocardiography after treatment. Unfortunately, because of the small sample size, we did not find any statistically significant difference. There was a trend showing that patients who benefited the most were those with the worst systolic function and with severely compromised segmental kinesis (P = NS). CONCLUSIONS: EECP is effective in relieving symptoms in patients with refractory angina and may reduce inducible ischaemia at dobutamine stress echocardiography, especially in patients with reduced systolic function and compromised segmental kinesis.

Aged↗

Noninvasive revascularization by enhanced external counterpulsation: a case study and literature review.

Nearly 8 million people in the United States suffer from symptoms of coronary artery disease (CAD). Unfortunately, the population of patients with ischemic coronary disease that is not readily amenable to surgical or percutaneous revascularization continues to grow. For patients who are not candidates for standard revascularization procedures and in whom aggressive medical therapy fails to control symptoms, enhanced external counterpulsation (EECP) is a new, noninvasive outpatient method to improve quality of life by decreasing ischemic symptoms and permit increased activity. We report the case of a 56-year-old woman with severe, symptomatic CAD receiving maximal medical therapy who underwent a course of EECP therapy because she was not a good candidate for other forms of revascularization. She demonstrated dramatic improvement in her anginal symptoms and complete resolution of myocardial ischemia on repeat nuclear stress imaging. This case suggests that EECP is a safe and effective method for reducing symptoms of myocardial ischemia in patients for whom standard percutaneous or surgical revascularization is not suitable treatment.

Activities of Daily Living↗

Successful treatment of symptomatic coronary endothelial dysfunction with enhanced external counterpulsation.

Enhanced external counterpulsation (EECP) is a valuable therapeutic option for patients with coronary artery disease and refractory angina. Although the exact mechanisms by which this technique exerts favorable effects remain unclear, improvement in endothelial function is considered a potential mechanism contributing to the clinical benefit associated with EECP. We describe a young woman with severely symptomatic coronary endothelial dysfunction in the absence of obstructive coronary artery disease who experienced a dramatic and sustained reduction in symptoms in response to a standard 35-hour course of EECP.

Adult↗

Techniques for IABP timing, use--and discontinuance. Counterpulsation can reduce ischemia and improve hemodynamics.

By restoring the balance between myocardial oxygen supply and demand, intra-aortic balloon counterpulsation can aid the ischemic or failing left ventricle. Rapid inflation and deflation of the balloon reduces afterload and improves coronary perfusion. Timing of inflation and deflation is adjusted according to the arterial pressure waveform. The balloon should inflate just after the aortic valve closes and deflate just before the aortic valve opens; early or late balloon inflation or deflation blunts the therapeutic effects. Discontinue the IABP support gradually; monitor the patient frequently for any signs of hemodynamic compromise, redevelopment of ischemic chest pain, or electrocardiographic changes.

Coronary Circulation↗

Experimental study of the effect of external counterpulsation on blood circulation in the lower extremities.

A bidirectional ultrasonic Doppler flowmeter with direct single sideband separation was used to measure blood flow in the femoral and dorsalis pedis arteries of 18 normal volunteers. Changes in blood-flow velocity and volume during external counterpulsation (ECP) with various sustaining times (the time for maintaining pressure) for inflation were studied. The results showed that blood-flow velocity in the femoral and dorsalis pedis arteries is increased significantly by ECP, but the change is not closely related to the duration of inflation. For a short sustaining time, the net forward blood-flow volume in arteries increased remarkably, but at longer sustaining times it dropped back significantly to a value even lower than that before ECP. The sustaining time for inflation to produce the maximum net forward flow volume (the optimal sustaining time of inflation) was found to be at one-quarter to one-third of the cardiac cycle. In a second study, changes in the calibre of the femoral artery and its collateral and anastomotic branches in the hind extremities in 5 dogs before and after ECP with an optimal sustaining time of inflation were examined by femoral arteriography. The experiments showed that the patency of collateral and anastomotic branches of the femoral artery was greater before than after ECP. The study suggests that ECP could be an effective treatment for improving the blood circulation in extremities.

Adult↗

A method to ease removal of surgically-introduced intra-aortic balloon counterpulsation catheters.

BACKGROUND: A surgical cut-down may be necessary when an emergency intra-aortic balloon counterpulsation catheter insertion has to be performed. Closure requires reopening the wound to extract the catheter and close the arteriotomy, or a graft has to be presutured to allow simple ligation. These methods are cumbersome. A method permitting rapid surgical access and easy removal in an intensive care unit is highly desirable. Such an insertion technique that, after insertion, includes placement of transcutaneous hemostatic purse-string sutures was evaluated. METHOD: All intra-aortic balloon catheter insertions done between August 1996 and March 2000, where all patients underwent an attempt at percutaneous intra-aortic balloon insertion, were evaluated. Failure to insert the balloon percutaneously was followed by direct surgical exposure and insertion with the placement of 2 transcutaneous purse-string sutures. The balloon pump catheter was removed when deemed appropriate and hemostasis was achieved by compression (percutaneous), or by tying of the preplaced sutures followed by compression. Patients were followed and both groups were compared with respect to mortality and vascular complications and any other complications were noted. RESULTS: There were 157 intra-aortic balloon insertions. Surgical introduction was required in 9 (5.7%) cases. These represent 17.3% of all emergency introductions. There was no statistical difference in original diagnosis, mortality, or vascular complications. The survivors (8/9) have been followed up for a mean of 2.8 years with no late complications. CONCLUSIONS: The removable transcutaneous suture method permits easy intra-aortic balloon catheter insertion and easy removal in an intensive care unit. This method has not been associated with complications in the follow-up period (mean 2.8 years).

Adult↗

Acute and chronic hemodynamic effects of enhanced external counterpulsation in patients with angina pectoris.

BACKGROUND: Enhanced external counterpulsation (EECP) is an effective noninvasive treatment for patients with angina pectoris. However, the hemodynamic effects of EECP are still unknown and have been theorized to simulate the clinical use of the intra-aortic balloon pump, enhancing cardiac output, stroke volume, and retrograde aortic diastolic flow. METHODS: Twelve hemodynamic parameters were measured, using the BioZ System (CardioDynamics International Corporation, San Diego, Calif) after 1 hour (n=22) and after 35 hours (n=16) of EECP treatment compared with baseline. The BioZ System noninvasively measures hemodynamic parameters using the thoracic electrical bioimpedance method. RESULTS: One hour of EECP treatment revealed a significant decrease in cardiac output, stroke volume, contractility, afterload, preload, and myocardial energy production, but systolic time ratios and thoracic fluid content were unchanged. However, after 35 hours of therapy, stroke volume (P < or = 0.05), index of contractility (P < or = 0.05), and thoracic fluid content (P < or = 0.01) were decreased. CONCLUSIONS: The acute reduction in contractility, preload, and concurrent bradycardia may have favorable hemodynamic effects for patients with angina pectoris. Further studies are needed to elucidate the mechanism of EECP therapy and its efficacy for patients with angina pectoris.

Aged↗

[Experiment study of the effect of enhanced external counterpulsation on shear stress].

This study inquired into the therapeutic mechanism of external counterpulsation(ECP) in the treatment of myocardial ischemia. Blood flow was measured at the arteria carotics, truncus brachiocephalics and other places in six chest-open dogs, and shear stress was operated. The statistical results show that the average, the range of change, and the changing rate were augmented with ECP, i.e. the phasic characteristics of shear stress were increased.

Animals↗

[Cerebral hemodynamic impairment and therapeutic effect of external counterpulsation on elderly patients with brain infarction].

Hemodynamic parameters of middle cerebral artery(MCA) were measured with Transcranial Doppler (TCD) in 31 elderly patients with brain infarction during convalescence and 28 healthy elderly controls. Twenty-two elderly patients with brain infarction and cerebral hemodynamic impaired were treated by External Counterpulsation(ECP). The results showed that the Vp and Vm of MCA in patients were significantly lower than that in the healthy controls(P < 0.001), the DVp, DVm and asymmetry of MCA in patients were greater than that in the healthy elderly(P < 0.001, P < 0.005). The Vp and Vm of MCA in patients after ECP were significantly higher than before(P < 0.001). The DVp, DVm and asymmetry of MCA in patients after ECP were significantly lower than before(P < 0.001, P < 0.005). The hemodynamic therapeutic effect is 81.8%.

Aged↗

[Therapeutic hemodynamic effects of external counterpulsation on elderly patients with brain infarction during convalescence].

The therapeutic hemodynamic effects of external counterpulsation(ECP) and medical routine therapy in elderly patients with brain infarction during convalescence were investigated by Transcranial Doppler (TCD). The results showed that hemodynamic parametres(Vp, Vm, DVp, DVm) and asymmetry of MCA in elderly patients with brain infarction who were treated with ECP have improved significantly(P < 0.001), but that of MCA in elderly patients with brain infarction who were treated with medical routine therapy have not significantly improved. Therapeutic hemodynamic effects of ECP on elderly patients with brain infarction were much better than that of medical routine therapy(P < 0.001).

Aged↗

[Effects of external counterpulsation on the pulsatility of blood pressure and blood flow in dogs].

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of artery blood pressure and blood flow in dogs and effects of enhanced external counterpulsation (EECP) on the pulsatility were taken in this study. Common carotid artery blood pressure and blood flow were measured in 6 beagle dogs that had suffered from an acute myocardial infarction 6 weeks before. A 6F tip transducer catheter was inserted into the right common carotid artery to measure blood pressure, and blood flow was measured in the left common carotid artery by an electromagnetic blood flow probe under anesthesia before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure were calculated to evaluate the pulsatility of arterial blood pressure. Blood pulse flow, pulsatility index (ratio of peak flow to trough flow) and standard deviation of blood flow were calculated to evaluate the pulsatility of blood flow. Mean vascular resistance (MVR) was calculated as MVR = mean blood pressure/mean blood flow. Blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 30 +/- 9 mmHg, 1.26 +/- 0.05 and 8.7 +/- 2.5 mmHg to 43 +/- 8 mmHg (P < 0.05), 1.54 +/- 0.13 and 12.4 +/- 2.0 mmHg (P < 0.05) before and during EECP, respectively. Blood pulse flow, pulsatility index and standard deviation of blood flow were elevated from 317 +/- 48 ml/min, 2.85 +/- 0.21 and 96 +/- 21 ml/min to 447 +/- 88 ml/min, 4.56 +/- 0.90 and 131 +/- 39 ml/min before and during EECP (P < 0.05). MVR was decreased from 578 +/- 72 before EECP to 476 +/- 85 Wood units during EECP(P < 0.05). These data demonstrate that EECP gives an elevation of pulsatility to blood pressure and blood flow, thus it may lead to the decrease of vascular resistance.

Animals↗

[A comparative study of finger plethysmography and aortic pressure for monitoring the effect of external counterpulsation].

Invasive pressure detecting and monitoring of aortic root was conducted in 20 volunteers so as to study the effect of Enhanced External Counterpulsation (EECP) on aortic pressure and finger plethysmography. The results demonstrated that the changes of aortic diastolic pressure linearly related to the counterpusation's bladder pressure, and the aortic augmentation increased to the top of 168.56 mmHg with a D/S ratio of 2.75(amplitude ratio of diastolic waveform and systolic waveform, D/S ratio) following the bladder pressure of 0.45 Kg/cm2. With the increase of bladder pressure, the dp/dt of aortic augmentation elevated gradually, but a down-regulating trend was seen in systolic waveform. During EECP, the starting time of plethysmographic augmentation had a mean delay of 108.20 +/- 25.70 ms comparing with that of aortic augmentation. The duration between the starting time of aortic systolic waveform and that of finger plethysmogram was arround 96.69 +/- 38.70 ms. When the bladder pressure changed, no significant difference was observed among them. The D/S ratio of finger plethysmographic waveform changed in concord with that of aortic pressure with the promotion of bladder pressure. Therefore, a relationship between aortic D/S ratio (Y) and plethysmographic D/S ratio (x) was constructed by the linear regression analysis: Y = 0.376 + 0.457X. It can be concluded that EECP has significant effects on aortic D/S ratio, aortic peak augmentation and its dp/dt value. Finger plethysmography, to date, still plays important roles in monitoring and controlling EECP work safely and effectively.

Adolescent↗