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PubMedDate not supplied

The effect of intra-aortic balloon counterpulsation on coronary blood flow velocity distal to coronary artery stenoses.

Despite the accepted clinical benefit of intra-aortic balloon counterpulsation (IABC), the physiologic explanation for its benefit remains controversial. Indirect methods of measuring coronary blood flow during IABC in obstructive coronary disease have yielded conflicting results. The direct measurement of coronary blood flow velocity distal to sites of stenoses by methods that do not potentially impede flow has not been previously reported. The aim of our study was to determine the effect of IABC on coronary blood flow velocity distal to a coronary stenosis by employing a method that would not impede flow through the stenosis. In an open-chest canine model, phasic and mean left anterior descending coronary artery flow velocities distal to varying degrees of stenosis were continuously measured by an epicardial Doppler probe with and without counterpulsation. All hemodynamic parameters were recorded in the absence of stenosis (n = 5) and the presence of subcritical (n = 5) and critical stenoses (n = 5). Heart rate was not affected by counterpulsation. Systolic blood pressure and rate-pressure product declined at all times with IABC. Compared to baseline, peak aortic diastolic pressure was augmented by an average of 24 mm Hg during IABC (p < 0.05). However, mean coronary artery flow velocities remained unchanged (101, 103 and 98% of baseline for no stenosis, subcritical stenosis and critical stenosis, respectively; p > 0.05 compared to baseline). Peak diastolic flow velocities were 106, 102 and 96% of baseline for no stenosis, subcritical and critical stenoses, respectively (p > 0.05). Despite the augmentation of peak diastolic pressure, distal coronary blood flow velocity was not increased by IABC in this canine model, irrespective of the severity of proximal coronary stenosis. These data suggest that augmentation of coronary artery flow distal to sites of stenoses is not primarily responsible for the clinical benefit observed when IABC is used in the setting of obstructive coronary artery disease. The reduction in afterload and myocardial oxygen demand observed in this model agrees with previous studies and likely accounts, at least in part, for the positive clinical results with IABC.

Animals↗

PubMed1976

Effect of intra-aortic balloon counterpulsation on the motion and perfusion of acutely ischemic myocardium. An experimental echocardiographic study.

The effect of intra-aortic balloon counterpulsation (IABC) on the motion and perfusion of ischemic left ventricular posterior myocardium was studied in 30 open-chest dogs, using ultrasound to register motion and 7-10 mu radioactive microspheres to determine perfusion. Circumflex coronary artery ligation produced acute aneurysmal bulging during isovolumetric contraction and diminished ischemic wall velocity during systolic ejection. Myocardial perfusion was determined in five dogs; perfusion of the area supplied by the ligated coronary artery fell from a control value of 72.9 +/- 13.8 (SE) to 30.0 +/- 2.3 cc/100 g/min (P less than 0.05) at 5 minutes after coronary occlusion. IABC was then administered for one hour, with a fall in aortic systolic pressure (112 +/- 6 to 105 +/- 7 mm Hg, P less than 0.05) and rise in peak aortic diastolic pressure (94 +/- 6 to 102 +/- 7 mm Hg, P less than 0.05). Despite this the ischemic area showed no change in perfusion (measured at the same time): 30.0 +/- 2.3 to 28.0 +/- 2.4 cc/100 g/min. Little change in wall motion occurred: aneurysmal bulging decreased modestly (4.5 +/- 0.3 to 3.6 +/- 0.3 mm, P less than 0.05), but ischemic wall velocity did not increase. After cessation of counterpulsation and one hour of coronary reperfusion aneurysmal bulging disappeared and wall velocity improved. The addition of norepinephrine (eight dogs) or nitroprusside (seven dogs) to intraaortic balloon counterpulsation did not cause a significant further improvement in the response of the dyskinesis during the period of ischemia. We conclude that IABC has little effect on ischemic dyskinesis, probably due to its failure to improve perfusion of the acutely ischemic myocardium.

Acute Disease↗

PubMedDate not supplied

Vascular complications of the intra-aortic balloon counterpulsation.

From September 1994 to December 2002, 6,274 cardiosurgery operations were performed at the Department of Cardiac Surgery, University Hospital, Hradec Kralove, Czech Republic. Intra-aortic balloon counterpulsation (IABP) was applied in 192 cases (3.1%). From this group of 192 counterpulsated patients 103 were successfully treated (53.6%); 89 counterpulsated patients (46.4%) died from the surgical procedure (30-day mortality rate). In 5 cases (2.6%) from the group of 192, the IABP was introduced before the operation. Ischemic changes of the limb were observed in 11 cases (5.7%). Significant bleeding occurred at the site of puncture in 6 cases (3.1%). Dissection of the femoral and iliac arteries was found in 2 patients (1.0%), perforation of the iliac artery in 1 case (0.5%). In 2 cases (1.0%) the balloon was led into the venous system. In case report No. 1 an introduction of the balloon under a sclerotic plaque of the descending aorta and iliac artery is described. In case report No. 2 a placement of the balloon in the venous bloodstream is reported.

Adult↗

PubMed1983

Intra-aortic balloon counterpulsation in an experimental model of myocardial infarction.

The efficacy of intra-aortic balloon counterpulsation for heart failure during acute myocardial infarction has been controversial, and early intervention has been suggested as crucial. We have examined this type of therapy in the intact anesthetized dog during complete occlusion of the proximal left anterior descending coronary artery with a balloon-tipped catheter. Group 1 (n = 8) represented untreated animals undergoing four hours of ischemia. Group 2 (n = 7) consisted of animals undergoing counterpulsation with an intra-aortic balloon after 15 minutes of ischemia. Initially, stroke volume and the mean rate of left ventricular fiber shortening were similarly diminished in both groups, while filling pressure rose proportionately. After four hours, the mean rate of fiber shortening, stroke volume, and left ventricular filling pressure rose to a greater extent in untreated compared to treated animals (p less than 0.01). The degree of swelling in ischemic tissue and the number of sites with ST-segment elevation and their sums were comparable in the two groups. Thus, intra-aortic counterpulsation applied early in the course of ischemia can improve global left ventricular dysfunction without affecting the extent of myocardial injury.

Animals↗

PubMedDate not supplied

Counterpulsation in experimental cardiogenic shock with ventricular arrhythmias. The antiarrhythmic effect of morphine.

In two groups of dogs a cardiogenic shock was induced and their circulation assisted by counterpulsation. In the second group aside from the counterpulsation, 4 mgrs/Kg of morphine was administered when stable ventricular arrhythmias appeared. Morphine showed to eliminate the ventricular arrhythmias in three cases and lessened them considerably in one, permitting better assistance with a counterpulsator.

Animals↗

PubMedDate not supplied

Counterpulsation in atrio-aortic bypass: theoretical and experimental aspects.

Mechanical support of the heart is becoming an established method for emergency situations or bridge to transplant applications. Nevertheless the discussion concerning the importance of co- or counterpulsation isn't yet finished. Using a theoretical model of the cardiovascular system, the influence of a LVAD triggered to co- and counterpulsation will be discussed. The theoretically obtained results are compared to a series of six experiments in calves, where the influence of LVAD-pumping in co- and counterpulsation pumping mode was investigated. Additional benefits were seen compared to the copulsation pump method: there was more reduction of the cardiac stroke work, afterload and an increase of the diastolic pressure, which is important for the coronary blood flow. In order to verify the benefits of the additional reduction of pressure work a small series of animal experiments was performed.

Animals↗

PubMed1975

[Effect of peripheral counterpulsation on the body of an animal with intact heart].

The effect of lasting peripheral counterpulsation upon the haemodynamics and the main biochemical factors of the blood was studied in 14 dogs with intact hearts. In cases of significant tachycardia counterpulsation in a 1:2 regimen results in only a partial reduction of the resistance to the cardiac output. This does not always permit to prevent the formation of the phenomenon of an elevated myocardial contractility. The haemodynamic conditions are most optimal in a 1:1 regimen of counterpulsation. Slowing down of the cardiac rhythm was achieved by means of hypothermia.

Acid-Base Equilibrium↗

PubMed1966

Current status of counterpulsation in cardiac assistance: a summary of experimental experience in the dog.

Synchronized counterpulsation was applied to two groups of nine dogs using a new fluid-coupled pulse generator. Pump performance and synchronization were superior to earlier pneumatic systems. Improvement in cardiac function was evidenced by reduction in left ventricular pressure, work and oxygen consumption. Peripheral hemodynamics were adversely affected as evidenced by reduction in blood pressure, cardiac output, renal and carotid blood flows and decrease in central venous oxygen saturation. Evaluation of counterpulsation in acute left ventricular failure produced in 15 dogs by serial coronary ligations revealed that the elevated left atrial pressure was reduced, but neither cardiac output nor arterial pressure was improved by counterpulsation.

Animals↗

PubMed1978

[The intraaortic balloon counterpulsation (author's transl)].

Indication for and clinical experience with intra aortic balloon counterpulsation at Harefield Hospital are reported. From Sept. 1973 to Sept. 1977, 87 patients had counterpulsation. Indications were: postinfarction cardiogenic shock in 28 cases; acute ischaemic episode in 19 and postoperative cardiogenic shock in 40. Of the 28 patients in postinfarction cardiogenic shock 15 underwent open heart surgery with an hospital mortality of 40%. All the patients with acute ischaemic episodes had surgery with an hospital mortality of 10%. In the group of 40 patients with postoperative cardiogenic shock overall mortality was 47%: it was of 18% in the 22 patients who had coronary artery bypass surgery while it was of 83% in the 18 patients who had valve surgery. Early recognition and treatment of conditions requiring counterpulsation is essential for achieving the best results.

Arrhythmias, Cardiac↗

PubMed1981

[Nitroglycerin, sodium nitroprusside and intra-aortic counterpulsation in acute myocardial infarct].

The effect of nitroglycerin and sodium nitroprusside in patients with acute myocardial infarction and signs of cardiac insufficiency was studied. These drugs reduced the increased pressure in the pulmonary artery. The systemic arterial pressure also reduced, but more markedly under the effect of nitroglycerin. Nitroglycerin often reduced the cardiac rhythm rate, whereas sodium nitroprusside caused no changes or increased it. Counterpulsation with an intra-aortic balloon was conducted in cardiogenic shock. The most marked positive changes in systemic arterial pressure occurred under the effect of counterpulsation. Changes in the cardiac output and pulmonoarterial pressure were much less conspicuous. The favourable dynamics disappeared in most patients after counterpulsation was discontinued.

Acute Disease↗

PubMed1981

Intra-aortic balloon counterpulsation: rationale, application and results.

Intra-aortic balloon counterpulsation is an effective means of reducing myocardial ischemia and supporting the failing circulation. Its therapeutic benefits are the direct result of distolic augmentation and systolic unloading, the former increasing myocardial perfusion and the latter enhancing cardiac performance. Indirect effect include diminution of ischemia by decrease in the determinants of myocardial oxygen demand and improved ventricular function secondary to the decreased ischemia. Intra-aortic balloon counterpulsation is indicated in clinical syndromes related to intractable cardiac ischemia, including myocardial infarction shock and severe left ventricular failure, refractory ischemic pains, and ventricular arrhythmias unresponsive to medical management. It is also of importance in other situations associated with low cardiac output. This therapeutic modality has recently been considered for early use in extensive myocardial infarction to limit cardiac damage and avert complications. Recent technical advances have facilitated the ease and safety of application of intra-aorta balloon counterpulsation. Complication are of low frequency but can be serious and employment of the method is predicated upon consideration of both potential benefits and risks.

Acute Disease↗

PubMed1982

[Counterpulsation in clinical practice].

A. N. Bakulev Institute of Cardiovascular Surgery, Academy of Medical Sciences of the USSR has 10 years of experience with counterpulsation in 209 patients with acute cardiac insufficiency. The main indications for assisted circulation were cardiogenic shock in 102 patients, myocardial infarction complicated by cardiac insufficiency in 43, cardiac insufficiency developing during or after cardiosurgical operations in 60 cases, prophylaxis of complications in high risk patients during intracardiac methods of investigation in 4 cases. The use of counterpulsation in 102 patients with post-infarction cardiogenic shock enabled the authors to liquidate the shock in half of the cases and to discharge 20% of the number from hospital. The study of peculiarities of shock enabled the authors to trace measures for decreasing mortality rate: use of counterpulsation as early as possible during transportation to hospital (29 cases), extension of indications for urgent surgery on the heart.

Assisted Circulation↗

PubMed1981

[Hemodynamic effect of intra-aortic balloon counterpulsation in the acute period of myocardial infarct].

The author studied changes in central hemodynamics during counterpulsation with an intra-aortic balloon in 38 patients in the acute period of myocardial infarction. The main hemodynamic values were determined by thermodilution. A positive effect of counterpulsation on the cardiac output was revealed in patients with congestive cardiac insufficiency and marked disorders of rhythm and conduction. It is recommended that counterpulsation with an intra-aortic balloon be included in the complex of measures for treating acute hemodynamic disorders in the first 24 hours of complicated myocardial infarction.

Adult↗

PubMed1979

Left ventricular mechanics of counterpulsation and left heart bypass, individually and in combination.

Counterpulsation and left heart bypass devices have been successfully used to salvage patients with severe left ventricular power failure following cardiopulmonary bypass. Each of these techniques is believed to reduce or minimize myocardial work, yet the effects of these devices on the force of myocardial contraction have not been defined. In the present investigation the effects of counterpulsation produced by intravascular (intra-aortic balloon pumping) and extravascular (pulsatile assist device) balloon devices, partial left atrial-aortic bypass, and total bypass on left ventricular mechanics were examined. The devices were studied individually and in combination in 10 anesthetized open-chest dogs. Left ventricular wall stress, external work, and contractility indices were calculated by computer using a changing volume spherical model of the left ventricle. Results indicate that although all currently available circulatory assist devices reduced peak left ventricular wall stress, a spectrum of relative effectiveness progressed from intra-aortic balloon pumping or pulsatile assist device alone through the combination intra-aortic balloon pumping plus the pulsatile assist device. Partial left heart bypass was more effective than intra-aortic balloon pumping plus the pulsatile assist device in reducing peak wall stress, but the difference was small. Total left heart bypass was vastly superior to any of the other modalities tested in its effects on peak wall stress as well as external work. The addition of counterpulsation to partial or total left heart bypass produced minimal changes in left ventricular systolic mechanics.

Animals↗

PubMed2006

Two-year outcomes in patients with mild refractory angina treated with enhanced external counterpulsation.

BACKGROUND: In the International Enhanced External Counterpulsation Patient Registry (IEPR), approximately 85% of the patients treated are in Canadian Cardiovascular Society (CCS) class III-IV with no option for further invasive coronary revascularization procedures. HYPOTHESIS: This study sought to determine whether it is clinically important to establish whether the observed durable reduction in disabling severe angina with enhanced external counterpulsation (EECP) treatment can be extended to those with less severe CCS class II angina, who also have no option for further revascularization. METHODS: This study evaluated the immediate response, durability and clinical events over a 2-year period after EECP treatment in 112 patients with Canadian Cardiovascular Society (CCS) class II angina versus 1346 patients with class III-IV angina using data from the International EECP Patient Registry (IEPR). RESULTS: Treatment with EECP significantly (by at least one CCS class) reduced angina frequency, nitroglycerin use, and improved quality of life in both groups. At 2-year follow-up, 74% of class II and 70% of class III-IV patients remained free of major adverse cardiovascular events (MACE) and continued to demonstrate a durable CCS class improvement over baseline. CONCLUSION: The robust effectiveness of EECP as a noninvasive device, together with its relatively low start-up and recurrent costs, makes it an attractive consideration for treating patients with milder refractory angina in addition to the patient with severely disabling angina treated in current practice.

Aged↗

PubMedDate not supplied

Enhanced external counterpulsation in the management of angina in the elderly.

This study was undertaken to determine whether enhanced external counterpulsation is a safe and effective treatment for angina in octogenarians. In this prospective observational study, demographic and clinical outcome data on patients consecutively enrolled in the International EECP Patient Registry was examined. Of the 3037 patients analyzed, 249 (8%) were >/=80 years old. Octogenarians were more likely to be female and have a history of congestive heart failure (41% vs. 29%; p<0.001). They were less likely to have had previous revascularization. Fewer patients in the octogenarian group (76% vs. 84%; p<0.01) completed a course of treatment. Of those octogenarian patients who completed treatment, 76% reported a reduction in angina and quality of life improved significantly. Adverse events related to treatment were low. At 6-month follow-up, 81% reported maintenance of angina improvement. Thus, enhanced external counterpulsation is a low-risk intervention that offers octogenarians the ability to return to more normal activity and a better quality of life.

Adrenergic beta-Antagonists↗

PubMed1990

"High-risk" percutaneous transluminal coronary angioplasty with preventive intra-aortic balloon counterpulsation.

Between January 1987 and February 1988, 1,385 patients underwent percutaneous transluminal coronary angioplasty; 27 procedures were performed using prophylactic intraaortic balloon counterpulsation. Twenty-four patients had poor left ventricular function (EF less than 40%), and coronary dilatation was performed in arteries opposite to an occluded myocardial necrosis related vessel. In three patients of advanced age with distal stenoses and normal left ventricular function a multivessel dilatation was performed. Primary success rate was achieved in all patients. There were no deaths, myocardial infarctions or emergency bypass operations in the hospitalization period. During the follow-up (9 to 21 months) there were 2 deaths, 1 cardiac transplantation, and 6 restenosis with repeated dilatation. If revascularization is warranted, in high-risk patients, coronary angioplasty can be performed safely and successfully with protection by intraaortic balloon counterpulsation. However the long-term prognosis of these patients is complicated by the presence of other high-risk variables, such as advanced age or poor left ventricular function.

Age Factors↗

PubMed1991

Vascular entrapment of intra-aortic balloon after short-term balloon counterpulsation.

Prolonged, continuous intra-aortic balloon (IAB) counterpulsation for several weeks can result in balloon entrapment secondary to thrombus formation in the balloon lumen. In this report, we describe a patient who developed IAB entrapment, early (1 wk) after initiation of counterpulsation. A trace amount of blood was noted in the tubing connecting the balloon catheter to the console for 3 days prior to IAB malfunction and vascular entrapment. We suggest that the balloon catheter be removed immediately when blood is detected in the external connecting tubing even if the IAB is functioning satisfactorily.

Adult↗