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PubMed1994

The hostile environment of the aging human aorta and the smaller patient--their implications for the intra-aortic balloon.

Intra-aortic balloon counterpulsation (IABC) has been a clinical modality since 1968. In the intervening years the patient population has become older, sicker and smaller. Modern balloon design permits the insertion of balloons into this evolving patient population and the balloon is increasingly threatened by the calcific plaque of the aging aorta and by the geometry of the shorter descending thoracic aorta in the smaller patient. Balloon sizing consideration and radiographic verification of balloon position within the aorta will reduce the incidence of balloon damage during IABC.

Aged↗

PubMedDate not supplied

Cardiogenic shock: thrombolysis or angioplasty?

Cardiogenic shock (CGS) occurs in 3 to 20% of patients presenting with acute myocardial infarction (MI), and it generally involves dysfunction of at least 40% of the total myocardial mass. Prior to the advent of balloon angioplasty and thrombolysis, in-hospital mortality was greater than 75%. This mortality rate has been consistent in reported series despite the advent of cardiac intensive care units, vasopressor, inotropic, and vasodilator therapy. Intra-aortic balloon counterpulsation therapy provides hemodynamic improvement, and it may provide some mortality benefit when used in conjunction with appropriate revascularization. Survival studies have shown that patency of the infarct-related artery is a strong predictor of survival. No randomized trials have been completed to examine which reperfusion therapy best treats this emergent situation. Subgroup analysis of large scale, multicenter trials, although underpowered, has shown no improvement in mortality with use of thrombolytic agents, leading many to advise use of mechanical intervention. In patients who present with acute MI with contraindications to thrombolysis, primary angioplasty is the treatment of choice. At selected centers, primary angioplasty is comparable to or better than thrombolytic therapy for patients presenting with acute MI, with or without CGS. Studies examining angioplasty in patients with CGS have shown high procedural success rates (75%) and reduced in-hospital mortality (44%), particularly in those patients with successful revascularization. Emergency bypass surgery may improve survival, but it is costly, unavailable to many, and often leads to excessive delays in therapy. If available, we believe that primary angioplasty is the treatment of choice for patients with CGS.

Angioplasty, Balloon↗

PubMed2000

Cardiogenic shock triggered by verapamil and atenolol: a case report of therapeutic experience with intravenous calcium.

Cardiogenic shock developed in a 72-year-old Japanese woman during combination therapy with verapamil and atenolol for recurrent supraventricular arrhythmia. She had coronary atherosclerosis, liver cirrhosis and bradycardia-tachycardia syndrome. Despite of the high-dose catecholamines and counterpulsation, she progressively deteriorated. Bolus administration of intravenous calcium chloride (CaCl2) immediately resolved her hemodynamic collapse.

Adrenergic beta-Antagonists↗

PubMed2006

Evolving treatment strategies for chronic refractory angina.

Chronic refractory angina is a term used to describe patients who, despite optimal medical therapy, have both angina and objective evidence of ischaemia. It is estimated that 5-15% of the 12 million patients with chronic angina in the US meet the criteria for having refractory angina. This review focuses on the following evolving pharmacological therapies for chronic refractory angina: L-arginine, ivabradine, ranolazine, nicorandil and trimetazidine. Evolving devices and invasive procedures including enhanced external counterpulsation, spinal cord stimulation, and transmyocardial revascularisation are also briefly discussed.

Acetanilides↗

PubMedDate not supplied

Early experience using a purpose-built pulse train stimulator for cardiac assistance with skeletal muscle.

We have developed and evaluated a prototype external pulse train stimulator for use with a new technique of circulatory assistance. This involves the use of skeletal muscle (latissimus dorsi) wrapped around the thoracic aorta as an entirely autologous extra-aortic counterpulsation system. The stimulator has been successful in initiating both muscle contraction at the desired part of the cardiac cycle (diastole) and the necessary fibre-type transformation required for long-term work (fatigue resistance). The background to the development of the stimulator and the early haemodynamic results are described in this paper. The evaluation of the prototype design and the areas for future development are discussed.

Animals↗

PubMed2004

Current and future treatment strategies for refractory angina.

Patients with refractory angina are not candidates for revascularization and have both class III or IV angina and objective evidence of ischemia despite optimal medical therapy. An estimated 300,000 to 900,000 patients in the United States have refractory angina, and 25,000 to 75,000 new cases are diagnosed each year. This review focuses on treatment strategies for refractory angina and includes the mechanism of action and clinical trial data for each strategy. The pharmacological agents that have been used are ranolazine, ivabradine, nicorandil, L-arginine, testosterone, and estrogen; currently, only L-arginine, testosterone, and estrogen are approved by the Food and Drug Administration. Results with the noninvasive treatments of enhanced external counterpulsation and transcutaneous electrical nerve stimulation are provided. Invasive treatment strategies including spinal cord stimulation, transmyocardial revascularization, percutaneous myocardial revascularization, and gene therapy are also reviewed.

Angina Pectoris↗

PubMed2000

[Circulatory support with the mechanical heart, "HeartMate"].

Treatment with the mechanical heart, HeartMate, has been introduced in Denmark. Short-term circulatory support can be obtained by intraaortic balloon counterpulsation, an external centrifugal pump and the total artificial heart. Long-term circulatory support can be established by treatment with the HeartMate. The principle of the mechanical heart is simple--a pump is implanted in parallel to the existing heart and connected to external, portable batteries. The patient quickly improves and is brought in an optimal state for transplantation. A few patients have been able to omit the subsequent heart transplantation. The patient's own heart improved during the treatment and the native heart functioned again after the system was explanted. The main complications during treatment are bleeding, infection, thromboembolic events and systemic failure. Permanent, fully implantable mechanical circulatory pumps are under development--which may herald the beginning of a whole new era for treatment of cardiac failure.

Assisted Circulation↗

PubMed1997

[Model-based study of time-dependent coronary blood flow distribution in left ventricular wall and its dependences on coronary pressure driving force].

The proposed model is of use for understanding the mechanism of intramyocardial circulation. There are three classical myocardial vascular nets in the model; each net has four vessel-size compartments which are characterized by time-dependent nonlinear resistance and compliance. The experimentally measured timed-varying perfusion and left ventricular pressure sources are used as driving inputs for the circulation. The phasic coronary blood flow characteristics predicted by the model exhibit waveform patterns that correlate qualitatively with the generally accepted results. In addition, more work is made about the myocardial infusion which is essentially controlled by the coronary pressure driving force. The results make it clear that the Intra-aortic balloon pumping and External counterpulsation are conducive to the balance between supply and demand of coronary blood flow.

Coronary Circulation↗

PubMed1999

[The study of the control system of new generation EECP].

A new algorithm for the inflation and deflation timing of the Enhanced External Counterpulsation (EECP) have been developed, A pentium PC and 16 bit microcontroller with parallel interrupt communication were used for developing a new kind of EECP system. The 16 bit microcontroller was used to collect and pre-process the ECG and EECP signals. The pre-processing data is transmitted to PC by the parallel communication interface. According to the new algorithm, PC sent out the sequential control signals and monitor the state of EECP. It is necessary to synchronize the time of aortic valve closure and diastolic augmentation during EECP, under the condition of the patients' safety, the effect of therapy have been extremely improved.

Algorithms↗

PubMedDate not supplied

Hemodynamic results of acute thoracic aortomyoplasty in a canine model: comparison of stimulation regimens.

Our previous investigations in a sheep model demonstrated that when electrical stimulation (ES) was applied to a newly mobilized latissimus dorsi muscle (LDM) in a work-rest regimen and at a rate of 15 contractions per minute, it did not damage this muscle. This regimen was used twice during a 60 minute period, once a day for 16 days, with no LDM damage. The goal of our current investigation was to apply this regimen in studies of acute thoracic aortomyoplasty. In two experimental groups, we mobilized the LDM but left it in situ. Two hours later, contractile force (CF) testing (20 g/kg preload, six impulses per burst) was performed until CF dropped to 50% of baseline. Recovery time needed to completely restore CF was calculated. In one group (six sheep), we applied continuous ES; in another (six sheep), we applied ES in a work-rest regimen (1 min work, 1 min rest). In two other groups of six dogs each, aortomyoplasty was performed; the LDM flap was subjected to ES immediately postoperatively (six impulses per burst; ventricular-LDM delay, 290 ms). Again, one group received continuous ES, and the other received work-rest ES. In the mobilized LDM under continuous ES, CF decreased to 50% of baseline values after 52 +/- 8 minutes, and returned to baseline after 84 +/- 16 minutes of rest. Under the work-rest regimen, this decrease took 105 +/- 8 minutes, and the return to baseline took 25 +/- 6 minutes (p < 0.05). In LDM subjected to work-rest ES, light microscopy revealed no additional damage to LDM tissue than was seen immediately after mobilization. However, LDM subjected to continuous ES had evidence of increased basophilic degeneration and wavy fibers. After acute thoracic aortomyoplasty, assisted hemodynamic values under the continuous ES exceeded unassisted values for only 40 minutes, compared with 100 minutes for work-rest ES (p < 0.05). When counterpulsation was completed, for continuous ES, recovery time to baseline was 96 +/- 9 minutes; for work-rest ES, it was only 43 +/- 6 minutes. In conclusion, a work-rest regimen of ES can be started safely immediately postprocedure.

Animals↗

PubMedDate not supplied

Skeletal muscle ventricles in circulation long-term: one hundred ninety-one to eight hundred thirty-six days.

It has been shown previously that skeletal muscle ventricles fashioned from canine latissimus dorsi muscle can function as effective blood pumps. We describe four dogs that have been reported on before but have now had skeletal muscle ventricles functioning as effective aortic diastolic counterpulsators for 191 to 836 days. One dog remains well with a skeletal muscle ventricle that has been pumping in circulation for 194 days; there has been no evidence of thrombus in the skeletal muscle ventricle cavity or thromboembolism. None of the three dogs that died had evidence of peripheral embolization, although two of those dogs had thrombus within the cavity of the skeletal muscle ventricle. This study proves that skeletal muscle ventricles can function long-term in the circulation and maintain diastolic pressure augmentation beyond 2 years. To the best of our knowledge, the dog whose skeletal muscle ventricle pumped in circulation for 836 days represents the longest living laboratory animal or human with a functioning heart assist device.

Animals↗

PubMed2004

Angina pectoris: a review of current and emerging therapies.

Angina pectoris is a debilitating indication of the presence of ischemic heart disease that affects millions of Americans. Although a number of pharmacologic treatments are available, the annual number of revascularization surgeries continues to rise in the United States. Other management strategies, such as spinal cord stimulation, enhanced external counterpulsation, metabolic modulators, and gene therapy, are being explored.

Adrenergic beta-Antagonists↗

PubMed1991

Temporary mechanical circulatory support for severe cardiac failure: experimental study.

We describe a technique for mechanical cardiac assistance in an acute model of severe cardiac failure. Cardiac dysfunction was induced by a high dose of halothane in 13 dogs. Seven served as controls. Following median sternotomy, a pneumatically driven device was implanted in the other six dogs in a para-aortic position, using a simple surgical technique without cardiopulmonary bypass. The aorta was cross-clamped during cardiac assistance. During hemodynamic studies, the seven control animals with induced cardiac failure showed high end-diastolic left ventricular and right atrial pressures with low cardiac index and systolic left ventricular and aortic pressures. All dogs in this group died within 30 minutes. Use of a monovalvular cardiac assist device in the experimental group of six dogs to pump blood from the aortic root to the descending aorta in a counterpulsation manner, confirmed good preservation of systemic hemodynamic parameters after induction of heart failure. All animals in this treated group survived more than 45 minutes. Hemodynamically, the device acts as a new ventricle and the impaired left ventricle functionally becomes a left atrium. This condition is clinically appropriate for recovery of left ventricular function in severe acute myocardial failure.

Animals↗

PubMed1990

[The treatment of acute severe cardiac insufficiency].

The clinical syndrome of severe acute heart failure may be caused by several distinct mechanisms. Some of these require a specific approach in addition to general measures, and prompt diagnosis is thus of great importance in order to define the initial and long-term therapeutic targets. This review recalls the basic principles of differential diagnosis and pharmacological treatment. The logistics of diagnosis and treatment inside the hospital are also discussed. The respective uses of mechanical ventilation, intraaortic balloon counterpulsation and ventricular assist devices are outlined.

Acute Disease↗

PubMed1989

[Cardiogenic shock].

In spite of advances in our understanding of the pathophysiology of cardiogenic shock, and the introduction of potent vasoactive pharmacological agents in its management, prognosis continued to be dismal with hospital mortalities over 85%. It has been only through additional and aggressive interventions--including intraaortic balloon counterpulsation (IABC), percutaneous transluminal coronary angioplasty (PTCA) and surgical revascularization--that improved survival can be achieved. Today's management of cardiogenic shock requires an early and integrated approach including physiological monitoring, vasoactive drugs, IABC, coronary angiography and PTCA, with the expectation of improving prognosis.

Angioplasty, Balloon↗

PubMed1993

Chronic in vivo function of a new ventricular assist device: the extracorporeal pulsatile assist device (EPAD).

An extracorporeal pulsatile assist device (EPAD) is a valveless, single-chambered, pneumatically-actuated blood pump composed of a graft conduit, connecting ring, bladder, and blowmolded housing. This allows a simple and quick surgical procedure and is easily actuated with a conventional intraaortic balloon pumping console if desired. To evaluate in vivo pump functions, the EPAD was tested in calves as a left ventricular assist device for 6-24 days. The EPAD was well synchronized to the natural heart beat up to 130 bpm in the counterpulsation mode with mild systemic heparinization (active clotting time: 200-250 seconds). Heart rate, coronary flow and cardiac output were not significantly changed by on-off testing. However, the pump showed promising diastolic augmentation (10.8% increase in the diastolic pressure time index) in these chronic animal experiments.

Animals↗

PubMed1996

Emergency percutaneous transluminal coronary angioplasty in acute myocardial infarction complicated with cardiogenic shock.

OBJECTIVE: To approach the efficacy of emergency percutaneous transluminal coronary angioplasty (PTCA) in Chinese patients with acute myocardial infarction (MI) complicated by cardiogenic shock. METHODS: Twelve patients with cardiogenic shock treated by emergency PTCA in this institution from January 1990 to May 1994 were retrospectively reviewed. There were anterio-lateral MI in 4 cases, inferio-posterial MI in 7, anterial and inferial MI in I, of which triple vessel disease in 4 cases, double vessel disease in 6, single vessel disease in I and left main coronary artery (LM) disease in 1. PTCA was performed under assistance of IABP in 7 cases and of centrifugal pump in 1. Only infarct-related Coronary artery (IRCA) was dilated during acute phase. Direct PTCA was done in 7 cases and rescue PTCA after failure of thrombolytic therapy in 5. RESULTS: PTCA was successful in 11 (91.7%) of the 12 cases, in 1 case with failure of PTCA the IRCA was reperfused by intracoronary thrombolytic therapy. Cardiogenic shock was reverted in 7 (63.6%) of the 11 cases reperfused by PTCA, among whom 6 (54.5%) survived. Four died of irreversible shock after 3 hours-9 days and 1 case with reversed shock died of cardiac rupture after 4 days. During a period of 13-55 months follow-up, long-term survivals were obtained in 4 cases. CONCLUSIONS: Emergency PTCA can achieve a high success rate and significantly decrease the mortality rate to less than 50% in Chinese patients with acute MI complicated with cardiogenic shock. The patients tolerate the PTCA procedure very well under the assistance of intra-aortic balloon counterpulsation (IABP) even in very severe condition.

Aged↗

PubMed1997

Dynamic aortomyoplasty: clinical experience.

Dynamic aortomyoplasty has been the subject of experimentation for the treatment of congestive heart failure during the last few years. This method consists of diastolic counterpulsation of the ascending aorta through the stimulation of the latissimus dorsi wrapped around it. This report describes the results of aortomyoplasty in a patient with dilated cardiomyopathy resulting from Chagas' disease and contraindications for heart transplantation or cardiomyoplasty.

Aorta↗