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At least 109 records · Page 6Linked to original sources

PubMed2005

Preoperative use of intra-aortic balloon counterpulsation in very high-risk patients prior to urgent noncardiac surgery.

The optimal management of high-risk patients requiring urgent or emergency noncardiac surgery when the options for further testing and evaluation are limited, is unclear. The focus of most of the literature, including the American College of Cardiology/American Heart Association guidelines, has been on patients undergoing elective as opposed to urgent surgery. A few reports have suggested the use of intra-aortic balloon counterpulsation as a strategy to help carry such patients through the procedure. We describe three such very high-risk patients who successfully underwent emergency surgery with prophylactic insertion of an intra-aortic balloon pump without any adverse cardiac events or device-related complications. Our experience, as well as that of others suggests that preoperative intra-aortic balloon counterpulsation is a useful (and safe) approach to help very high-risk patients undergo urgent and emergency noncardiac surgery. Randomized trials are needed to assess whether balloon counterpulsation offers an incremental benefit over aggressive preoperative beta blockade.

Aged↗

PubMed1990

A comparative evaluation of pulmonary artery balloon counterpulsation and a centrifugal flow pump in an experimental model of right ventricular infarction.

To compare the efficiency of pulmonary artery balloon counterpulsation and a centrifugal flow pump in reversing the hemodynamic consequences of acute right-sided heart failure, we employed both devices in 14 Yorkshire pigs in which right ventricular infarction was created via surgical ligation of branches of the right coronary artery. Pulmonary artery balloon counterpulsation improved some of the indicators of right heart failure, as manifested by significantly decreased right atrial pressure and increased mean systemic blood pressure. In contrast, the centrifugal flow pump consistently and significantly reversed all of the hemodynamic consequences of right ventricular infarction. In comparison to pulmonary artery balloon counterpulsation, the centrifugal flow pump resulted in lower right atrial pressures (p=0.020), lower mean pulmonary pressures (p less than 0.0001), increased left atrial pressures (p=0.026), increased cardiac output (p less than 0.0001), and increased mean systemic blood pressures (p less than 0.0001). Possible mechanisms to explain the superiority of the centrifugal flow pump include better hemodynamic unloading of the failing myocardium and independence from right ventricular output.

Animals↗

PubMedDate not supplied

Blood flow to the latissimus dorsi muscle pouch during chronic counterpulsation stimulation.

The cyclic contraction of a skeletal muscle ventricle (SMV) stimulated in counterpulsation results in phasic perfusion of the muscle. Perfusion will occur primarily during cardiac systole when the muscle is relaxed. However, the resting preload of the SMV will be systolic arterial pressure, which will impede blood flow to the relaxed muscle. To determine the effect of chronic counterpulsation stimulation on the blood flow to an SMV and identify stimulation regimens that prevent the risk of chronic ischemia, SMVs were created in four mongrel dogs by implementing an implantable mock circulation device. The SMV was stimulated in counterpulsation for 4 weeks after a 2-week vascular delay period and 2 weeks of low-frequency muscle conditioning. During biweekly studies, the muscle was stimulated in four modes against preloads varying from 20 to 120 mm Hg. Resting blood flow decreased significantly at preloads greater than 60 mm Hg. Normalized blood flow increased between 10% and 30% during stimulation; greater increases corresponded to more demanding stimulation modes. The elevated blood flow during stimulation, however, decreased with increasing preload. Stroke work increased with increasing preload until preload exceeded 100 mm Hg. The decreased blood flow and increased stroke work occurring at higher preloads indicate that the supply/demand ratio becomes compromised with increasing preload. A hyperemic response occurred during the resting beats after a stimulated beat, increasing the volume blood flow by as much as 80%. This response occurred regardless of preload or stimulation rate. If the SMV relaxed before the onset of systole, a hyperemic response occurred within the stimulated beat.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2004

[The hemodynamic and myostimulation regimens parallels of the extraaortic counterpulsation and skeletal ventricle in the experiment].

OBJECTIVE: Our investigation was aimed to evaluate the effect of extraaortic counterpulsation to central hemodynamics during the two modes of latissimus dorsi muscle electrostimulation. MATERIAL AND METHODS: Two groups of experimental dogs were divided into two subgroups and affected with continuous and work-rest regimens of stimulation. In one group latissimus dorsi muscle was mobilized and left in situ. The contraction force was measured before and during experiment, until it decreased till 50%. Recovery time needed to completely restore contraction force was calculated. In the second group latissimus dorsi muscle was stimulated just after aortomyoplasty and skeletal muscle ventricle by using LD PACE II electrostimulator (ventricle - muscle delay 290 ms). RESULTS: By using continuous stimulation in the first group the contraction force decreased till 50% of pre-assist level after 52+/-8 minutes and returned to baseline after 84+/-16 minutes of rest. Under the work-rest regimen this decrease lasted 105+/-8 minutes and returned to baseline after 25+/-6 minutes (p<0.05). After this regimen light microscopy did not revealed significant changes of muscle tissue. After continuous stimulation increased basophilic degeneration and wavy fibrils were revealed. Thoracic aortic counterpulsation by using continuous stimulation increased hemodynamic parameters from pre-assisted level in 40 minutes. The hemodynamic parameters during work-rest regimen became better after 20 minutes and lasted 100 minutes (p<0.05). When counterpulsation was completed, recovery time to baseline in case of continuous electrostimulation was 96+/-9 minutes; in case of work-rest electrostimulation, it was only 43+/-6 minutes. CONCLUSIONS: Work-rest regimen using LD PACE II electrostimulator may be used safely immediately post cardiac assist procedure.

Animals↗

PubMed2004

[The use of intraaortic balloon counterpulsation in patients with acute myocardial infarction].

Intraaortic balloon counterpulsation was implemented in 11 patients with acute myocardial infarction and 1 patient with unstable angina. All patients had severe multivessel coronary artery disease. In 9 patients counterpulsation was used in conjunction with percutaneous transluminal coronary angioplasty, in 3 - with thrombolytic therapy. During hospitalization 2 patients died of progressing heart failure, while significant improvement of hemodynamic parameters occurred in other patients. Thus intraaortic balloon counterpulsation used in combination with angioplasty and thrombolytic therapy is an easily accessible highly effective method of treatment of cardiogenic shock in patients with acute myocardial infarction

Angioplasty, Balloon, Coronary↗

PubMed1991

Aortic counterpulsation for up to 28 days with autologous latissimus dorsi in sheep.

This article reports the development and assessment of an entirely autologous extraaortic counterpulsation system using skeletal muscle (latissimus dorsi). The technique has been performed and assessed in 16 sheep to quantify the effectiveness of counterpulsation over periods up to 28 days and to optimize the stimulation regimens for muscle contraction and fiber-type transformation. Hemodynamic changes have been quantified by calculation of the endocardial viability ratio. This has shown an increase of between 12% and 89% for 28 days. The wide variety of increase observed has been related to the development of an optimum flap configuration. The technique of surface impedance monitoring of flap blood flow has allowed the start of electrical stimulation after 48 hours with the introduction of hemodynamic benefit (1:4 mode) during the process of fiber-type transformation (in situ training). Extraaortic counterpulsation with autologous latissimus dorsi has been shown to be effective and safe for as long as 28 days. It has not been associated with any thromboembolic or infective complications, which we attribute to the exclusion of any foreign material in the design.

Animals↗

PubMed1979

Comparative effect of counterpulsation and bypass on left ventricular myocardial oxygen consumption and dynamics before and after coronary occlusion.

In this preparation counterpulsation effect was found equivalent to 42 +/- 7% of complete left ventricular bypass before, and 46 +/- 9% post-coronary occlusion. We conclude that counterpulsation is effective mainly by reducing a major determinant of myocardial oxygen consumption, i.e., afterload, whereas left ventricular bypass by reducing primarily preload results in secondary afterload reduction when peripheral resistance is unchanged. At the higher left ventricular bypass levels, reduction of myocardial oxygen consumption is far greater than during balloon counterpulsation. Acute functional loss of myocardium does not alter the effect of these assist methods regarding the reduction of myocardial oxygen consumption. Whether selection of either method for clinical application should be made only on the basis of its capability for reduction of myocardial oxygen consumption remains to be justified by conclusive demonstration of beneficial effect of reduction of myocardial oxygen consumption in the specific circulatory disorders.

Animals↗

PubMed1979

Effects of intraaortic balloon counterpulsation on regional myocardial function during acute coronary occlusion in the dog.

The effects of intraaortic counterpulsation on regional myocardial function were studied using ultrasonic dimension gauges in 24 open chest dogs. Pairs of ultrasonic crystals were implanted in the subendocardium of the left ventricle in control, marginally ischemic and ischemic segments. After coronary arterial occlusion, the end-diastolic length of all three segments was increased. Segment shortening was rapidly replaced by systolic expansion in the ischemic segment. In the marginal segment, active shortening decreased by 53% and, in the control segment, shortening was augmented by compensatory operation of the Frank-Starling mechanism. Balloon pumping initiated 10 minutes after coronary occlusion resulted in an increase in mean aortic diastolic pressure from 103 to 115 mm Hg without any significant change in peak systolic pressure. In the marginal segment, end-diastolic length decreased by 3%, and previously reduced shortening increased to 82% of control value, deteriorating again with discontinuation of counterpulsation. Balloon pumping produced no change in the dyskinetic motion of the ischemic segment but caused compensatory augmentation of shortening of the control segment. Thus, counterpulsation selectively improved segment function of the marginally ischemic segment, presumably as a result of a regional increase in myocardial blood flow and in availability of oxygen due to augmented perfusion pressure. The systolic unloading effect was counterbalanced by improved cardiac performance.

Acute Disease↗

PubMed1984

Identification of patients at high risk for complications of intraaortic balloon counterpulsation: a multivariate risk factor analysis.

Risk factors for vascular complications of intraaortic balloon (IAB) counterpulsation were evaluated in 206 consecutive patients. The approach was percutaneous in 105 patients and surgical cutdown in 101. Vascular complications occurred in 42 patients, and of these 21 required surgery. Multivariate analysis demonstrated the following major risk factors for vascular complications: preexisting peripheral vascular disease (PVD) defined as a history of claudication, femoral bruit or absent pedal pulse (p less than 0.01); and the use of the percutaneous approach (p = 0.02). Evidence of PVD was particularly predictive of major vascular complications requiring surgery (p less than 0.01). In patients with evidence of previous PVD, the risk for a major vascular complication was 31% with the percutaneous, and 16% with the surgical cutdown approach. Without PVD, the risk for a major vascular complication was 4 times higher in women (15%) than in men (3.5%), but in the presence of PVD gender had no significant effect (p = 0.03). Age, duration of IAB counterpulsation and indication for insertion were not significant risk factors. It is concluded that (1) without previous PVD, women are at greater risk than men for major vascular complications (due to smaller arterial size); and (2) evidence of previous PVD identifies patients at high risk for major vascular complications with IAB counterpulsation, particularly by way of the percutaneous approach.

Assisted Circulation↗

PubMed1977

Treatment of cardiogenic shock in myocardial infarction by intraaortic balloon counterpulsation surgery.

Thirty-seven patients in cardiogenic shock due to acute myocardial infarction were treated with intraaortic balloon counterpulsation and/or surgery. Eighteen of these patients were treated with counterpulsation alone; eight survived and five were in functional class I or II at the time of follow-up; two were in functional class III, and one was in functional class IV. Nineteen patients were treated surgically, eight survived and seven were in functional class I or II at the time of follow-up; one was in functional class III. Good functional recovery with counterpulsation alone is most common with inferior infarction. With surgery, functional recovery depends not only on the extent of the infarction and the coronary anatomy, but also on the ability to perform surgery within 12 hours of infarction or to support the patient with mechanical means for 10 to 14 days after the infarction and then perform surgery.

Adult↗

PubMed1993

Enhanced coronary blood flow velocity during intraaortic balloon counterpulsation in critically ill patients.

OBJECTIVES: The aim of this study was to assess coronary blood flow during intraaortic balloon counterpulsation by direct measurement. BACKGROUND: In a majority of human studies, increased coronary blood flow during intraaortic balloon counterpulsation measured by indirect techniques has not been consistently demonstrated. METHODS: Hemodynamic variables and coronary blood flow velocity (20-MHz Doppler-tipped catheter) data were measured in 19 patients requiring intraaortic balloon pumping for clinical indications (11 patients had acute myocardial infarction [9 with shock], 6 had unstable angina, 1 had acute mitral regurgitation and 1 was at high risk undergoing angioplasty). Hemodynamic data, mean and phasic diastolic flow velocity and velocity-time integrals (computed from digitized waveforms) were analyzed during periods of 1:1 balloon counterpulsation. RESULTS: Intraaortic balloon pumping decreased systolic pressure (6 +/- 10%, p < 0.001) and increased diastolic pressure (80 +/- 30% from baseline, p < 0.001) without changing RR interval. Peak phasic, mean coronary flow velocity and diastolic flow velocity integral were significantly increased (115 +/- 115%, 67 +/- 61%, 103 +/- 81%, respectively, all p < 0.001) during intraaortic balloon pumping. In addition, although a wide splay of data was evident due to operator set variations in balloon inflation and deflation timing, the greater increases in diastolic flow velocity integral (DFVi) occurred in patients with basal systolic pressure < or = 90 mm Hg (% delta DFVi = 102 - 0.1.[unaugmented systolic pressure], SEE = 21.7 mm Hg, r = 0.30, p < 0.001). CONCLUSIONS: Intraaortic balloon pumping unequivocally and significantly augments proximal coronary blood flow velocity, nearly doubling the coronary flow velocity integral in most patients. This mechanism may be a significant means of ischemia relief in hypotensive patients.

Blood Flow Velocity↗

PubMed1984

A technique for immediate manual external aortic counterpulsation during cardiac surgery.

Intraaortic balloon pump counterpulsation is well established as a lifesaving measure. Aortic counterpulsation may be achieved externally as well as internally. A simple technique for manual external aortic counterpulsation during cardiovascular surgical procedures is presented. This technique is available on immediate demand and identical in effect to intraaortic balloon pumping, and it may be lifesaving in patients with acute cardiovascular decompensation since it allows time for institution of necessary emergency therapy.

Aorta↗

PubMed1985

The hemodynamic effects and mechanism of action of pulmonary artery balloon counterpulsation in the treatment of right ventricular failure during left heart bypass.

The efficacy of pulmonary artery balloon counterpulsation (PABC) was evaluated in improving right ventricular (RV) output during left heart bypass for global cardiac failure. In 13 pigs, a 40-ml balloon was positioned within a graft anastomosed to the pulmonary artery distal to the pulmonary valve, and left heart bypass was instituted from the left atrium to the carotid artery. Global myocardial failure was produced by an infusion of propranolol (range, 25 to 78 mg). In this model, RV output decreased despite volume loading to a right atrial pressure of 15 mm Hg and atrioventricular sequential pacing at 100 beats per minute. Pulmonary artery balloon counterpulsation increased both RV output (from 519 +/- 76 to 1,117 +/- 110 ml/min; p less than 0.01) and RV systolic stroke work (from 1.3 +/- 0.4 to 2.3 +/- 0.6 gm-m; p less than 0.01). Right atrial pressure decreased (from 15.5 +/- 0.9 to 10.7 +/- 1.0 mm Hg; p less than 0.01) in 8 of the pigs studied during RV failure. In 5 pigs, ventricular fibrillation occurred without a stable model of RV failure, and there was no cardiac output before or after counterpulsation. The mechanism of action of PABC was studied by placing a flow probe around a large branch of the right pulmonary artery. During RV failure, balloon inflation caused flow through the pulmonary circulation, and ventricular systole resulted in filling of the graft. During ventricular fibrillation, balloon inflation and deflation produced only a to-and-fro movement of blood in the pulmonary artery branch without net forward flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Use of a counterpulsation balloon as a substitute for the pulmonic valve: a new application.

An inflatable, 3-ml balloon positioned within the distal right ventricular outflow tract was used to restore pulmonic valve function in 8 dogs that had undergone open-chest valvectomy. Balloon inflation and deflation were accomplished with a counterpulsation console. Valvectomy produced loss of the pulmonic incisura, a decrease in pulmonary artery diastolic pressure (PADP; mean +/- standard error) (9.5 +/- 1.3 versus 4.4 +/- 0.6 mm Hg, p less than 0.01), and an increase in pulmonary artery pulse pressure (PAPP) (8.6 +/- 0.7 versus 19.1 +/- 1.9 mm Hg, p less than 0.01) without significantly affecting forward cardiac output (CO) (1,750 +/- 110 versus 1,880 +/- 230 ml/min, p is not significant). Properly timed counterpulsation restored the pulmonic incisura, raised the PADP from 6.1 +/- 0.8 to 9.5 +/- 0.8 mm Hg (p less than 0.01), lowered the PAPP from 15.1 +/- 1.4 to 10.6 +/- 1.0 mm Hg (p less than 0.01), and raised the forward CO from 1,850 +/- 260 to 1,920 +/- 260 ml/min (p less than 0.01). The injection of glass beads, 40 to 150 microns in diameter, into the right ventricular outflow tract increased pulmonary vascular resistance from 383 +/- 87 to 730 +/- 150 dyne . sec cm-5 (p less than 0.05) and decreased forward CO from 1,850 +/- 260 to 1,570 +/- 230 ml/min (p less than 0.05). Following this injection, counterpulsation again restored the pulmonic incisura, raised the PADP from 9.3 +/- 1.4 to 16.0 +/- 1.8 mm Hg (p less than 0.01), lowered the PAPP from 25.0 +/- 2.5 to 18.2 +/- 2.5 mm Hg (p less than 0.01), and raised the forward CO from 1,570 +/- 230 to 1,720 +/- 220 ml/min (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

The muscle-powered dual-chamber counterpulsator: rheologically superior implantable cardiac assist device.

To enable long-term studies of a totally implantable cardiac assist device powered by transformed fatigue-resistant skeletal muscle, we developed a dual-chamber extraaortic counterpulsator implanted, 2 of which fluid for power transfer. Six dogs had our dual-chamber extraaortic counterpulsator implanted, 2 of which had undergone prior transformation of their latissimus dorsi muscle. The blood pump, with a Dacron graft at each end, was anastomosed end-to-side and parallel to the thoracic aorta, allowing continuous blood flow to minimize thrombus formation caused by stasis and turbulence. The blood pump was powered by a hydraulic bulb placed beneath the latissimus dorsi muscle. The latissimus dorsi muscle was stimulated to contract during diastole using a synchronized burst electrical stimulator. The ratio of diastolic pressure time product over systolic time tension index, which reflects the myocardial oxygen supply and demand ratio, was calculated from ascending aortic pressure tracings. A consistent increase in this ratio of 44% in 4 dogs with nontransformed latissimus dorsi muscle and of 70% in 2 dogs with transformed latissimus dorsi muscle was obtained when the device was activated. Preliminary chronic implantation studies using a Medtronic cardiomyostimulator (Model SP1005) as the burst stimulator for our dual-chamber extraaortic counterpulsator produced an average augmentation in aortic diastolic pressure of 34 mm Hg for up to six days. Our results indicate that, with further refinement of this device, a long-term totally implantable cardiac assist device powered by endogenous skeletal muscle will be feasible.

Animals↗

PubMed2003

Survival of patients treated with intra-aortic balloon counterpulsation for cardiogenic shock in a tertiary centre: variables correlated with death.

OBJECTIVE: To describe the characteristics and mortality rates of 132 cardiogenic shock patients treated with intra-aortic balloon counterpulsation at a university hospital. INTERVENTIONS: All patients underwent intra-aortic balloon counterpulsation. A total of 99 out of 132 patients were revascularized with angioplasty, surgery or were transplanted (intervention group), 33 out of 132 had no further intervention (no-intervention group). MEASUREMENTS AND RESULTS: Overall mortality was 54.5% (72/132). In the intervention group mortality was 50.5% (50/99), in the no-intervention group mortality was 66.6% (22/33). The odds ratio for death comparing the intervention group with the no-intervention group was 0.533 (95% confidence interval 0.238-1.189, P = 0.122). By univariate analysis, diabetes and a left ventricular ejection fraction of less than 0.35 represented an increased odds ratio of death of 4.25 (1.813-9.965, P = 0.001) and 3.03 (1.22-7.54, P = 0.015), respectively. A lactate level greater than 2.5 mg/dl at baseline resulted in an increased odds ratio of death of 5.185 (1.988-13.525, P = 0.0001). Using a multivariate logistic regression analysis, a left ventricular ejection fraction less than 0.35 and diabetes remained significantly correlated with death. CONCLUSION: Mortality rates remain high in cardiogenic shock patients in need of intra-aortic balloon counterpulsation. The odds ratio for death tended to be lower in the intervention group compared with the no-intervention group, although the absolute difference in mortality as a result of an intervention was only 15.2%, and did not reach statistical significance probably because of the small sample size. Diabetes and an ejection fraction lower than 35% are significant predictors for a worse prognosis.

Adult↗

PubMed1977

Experience with counterpulsation in cardiac surgical patients.

At Sheffield Regional Cardiothoracic Unit, the AVCO intra-aortic balloon pump has been used on 25 occasions in 21 months. Of the 25 patients, 12 survived and left hospital. The procedure is particularly beneficial in patients who have suffered some failure of myocardial protection during operation and to those who are suffering from acute ischaemia or the sequelae of myocardial infarction. The place of preoperative counterpulsation is discussed. Patients with long-standing cardiac disease who have emergency surgery benefit less from counterpulsation. Those patients with chronic ischaemic damage to the heart have nothing to gain from the use of counterpulsation.

Adolescent↗

PubMed1979

Arterial counterpulsation in continuing myocardial ischaemia after acute myocardial infarction.

Twenty-six patients underwent arterial counterpulsation for refractory heart failure without shock complicating acute myocardial infarction. Patients were divided into a group of 12 with continuing myocardial ischaemia, evidenced by anginal pain associated with abnormal ST segment elevation, and a group of 14 without continuing ischaemia. Clinical features (apart from pain) and prognostic indices were similar in the two groups when counterpulsation was started but short- and long-term results were different. Hospital survival was 92 per cent (11/12) and 43 per cent (6/14), respectively, in the groups with and without ischaemia and four-year survival was 73 per cent and 7 per cent. Counterpulsation is of greatest value in acute infarction when used to relieve myocardial ischaemia.

Assisted Circulation↗