Intra-aortic balloon counterpulsation in the treatment of infarction-related cardiogenic shock--review of the current evidence

The European ST-elevated myocardial infarction (STEMI) guideline suggested the intra-aortic balloon pump (IABP) with a recommendation level I and a level of evidence C as an effective measure in combination with balloon angioplasty in patients with cardiogenic shock (CS), stent implantation, and inotropic and vasopressor support. Similarly, upon mechanical complication due to myocardial infarction (MI), the guideline suggests that in patients with a ventricular septal defect or in most patients with acute mitral regurgitation, preoperative IABP implantation is indicated for circulatory support. The American College of Cardiology/American Heart Association STEMI guideline recommends the use of the IABP with a recommendation level I and a level of evidence B if CS does not respond rapidly to pharmacological treatment. The guideline notes that the IABP is a stabilizing measure for angiography and early revascularization. Even in MI complications, the use of preoperative IABP is recommended before surgery. Within this overview, we summarize the current evidence on IABP use in patients with CS complicated by MI. From our Cochrane data analysis, we conclude that in CS due to acute MI (AMI) treated with adjuvant systemic fibrinolysis, the IABP should be implanted. In patients with CS following AMI, treated with primary percutaneous coronary intervention (PCI), the IABP can be implanted, although data are not distinctive (i.e., indicating positive and negative effects). In the future, randomized controlled trials are needed to determine the use of IABP in CS patients treated with PCI. When patients with CS are transferred to a PCI center with or without thrombolysis, patients should receive mechanical support with an IABP. To treat mechanical MI complications-in particular ventricular septal defect-patients should be treated with an IABP to stabilize their hemodynamic situation prior to cardiac surgery. Similar recommendations are given in the German Austrian guidelines on treatment of infarction-related CS patients (http://www.awmf.org/leitlinien/detail/ll/019-013.html).     

Intra‐Aortic Balloon Pump Support in the Isolated Beating Porcine Heart in Nonischemic and Ischemic Pump Failure

The blood pressure changes induced by the intra‐aortic balloon pump (IABP) are expected to create clinical improvement in terms of coronary perfusion and myocardial oxygen consumption. However, the measured effects reported in literature are inconsistent. The aim of this study was to investigate the influence of ischemia on IABP efficacy in healthy hearts and in shock. Twelve slaughterhouse porcine hearts (hearts 1–12) were connected to an external circulatory system, while physiologic cardiac performance was restored. Different clinical scenarios, ranging from healthy to cardiogenic shock, were simulated by step‐wise administration of negative inotropic drugs. In hearts 7–12, severe global myocardial ischemia superimposed upon the decreased contractile states was created. IABP support was applied in all hearts under all conditions. Without ischemia, the IABP induced a mild increase in coronary blood flow and cardiac output. These effects were strongly augmented in the presence of persisting ischemia, where coronary blood flow increased by 49 ± 24% (P < 0.01) and cardiac output by 17 ± 6% (P < 0.01) in case of severe pump failure. As expected, myocardial oxygen consumption increased in case of ischemia (21 ± 17%; P < 0.01), while it slightly decreased without (?3 ± 6%; P < 0.01). In case of progressive pump failure due to persistent myocardial ischemia, the IABP increased hyperemic coronary blood flow and cardiac output significantly, and reversed the progressive hemodynamic deterioration within minutes. This suggests that IABP therapy in acute myocardial infarction is most effective in patients with viable myocardium, suffering from persistent myocardial ischemia, despite adequate epicardial reperfusion.     

Elective intraaortic balloon counterpulsation for high-risk off-pump coronary artery bypass operations

BACKGROUND: Dislocations of the heart required for exposure and construction of distal anastomoses often produce hemodynamic instability when performing coronary artery revascularization without using cardiopulmonary perfusion (OPCAB). We report our early experience with elective intraaortic balloon counterpulsation (IABP) to enable and facilitate selected high-risk patients to undergo OPCAB. METHODS: Sixteen high-risk patients undergoing multivessel OPCAB using elective IABP are reported. The patients were believed to be at increased risk because of the presence of severe proximal multivessel coronary artery obstruction, ventricular dysfunction, recent acute myocardial infarction, cardiomegaly-cardiomyopathy, and documented cerebral vascular disease. The presence of significant comorbid disease also made the avoidance of cardiopulmonary bypass desirable, if at all possible, in all patients. RESULTS: The IABP appeared to facilitate the intraoperative management of our series of patients. This was evidenced by improved hemodynamic stability and virtual elimination of the need for inotropic support during the dislocations of the heart needed for exposure and construction of distal anastomoses. There were no complications related to use of IABP. There was one death. CONCLUSIONS: We believe this strategy to use IABP selectively can allow surgeons to safely extend the benefits of OPCAB procedures to high-risk patients and avoid dangerous hemodynamic instability that otherwise, often occurs.     

Usefulness of preoperative intraaortic balloon pump therapy during off-pump coronary artery bypass grafting in high-risk patients

BACKGROUND: In off-pump coronary artery bypass grafting (OPCABG) surgery, the most critical complication is hemodynamic deterioration, which can occur during displacement of the heart to expose the target vessels. Preoperative intraaortic balloon pump (IABP) therapy improves cardiac performance and facilitates access to the target coronary artery while maintaining hemodynamic stability, especially in high-risk patients. METHODS: One hundred thirty-three consecutive patients who underwent OPCABG through sternotomy between April 2000 and July 2003 were studied. We compared the clinical results of 32 patients who underwent preoperative IABP placement (group 1) with those of 101 patients who did not have IABP placement (group 2). Of the 32 patients satisfying the insertion criteria, 15 had critical left main artery disease, 20 had unstable angina, 5 had acute myocardial infarction, and 5 had left ventricular dysfunction. RESULTS: There were no significant differences in the average number of distal anastomoses performed between group 1 and group 2 (3.1 +/- 0.8 versus 3.3 +/- 0.9, p = not significant). The complete revascularization rate was 95% in both group. There was no conversion to on-pump surgery in either group. There was no operative death in group 1 and only 1 death in group 2. In group 1, the number of patients who required prolonged ventilatory support (longer than 48 hours) was higher (3 versus 1, p = 0.036), and there was a higher incidence of low cardiac output syndrome (1 versus 0, p = 0.074). There were no IABP-related complications in group 1. CONCLUSIONS: Preoperative IABP therapy for high-risk coronary patients is very effective in preventing hemodynamic instability and providing surgical results comparable with those in moderate- to lower-risk patients.     

A case of ischemic mitral regurgitation treated by mitral annuloplasty (MAP) and coronary artery bypass grafting (CABG)]

A 79-year-old woman with a previous history of myocardial infarction, suffered acute myocardial infarction again. A coronary angiogram revealed triple vessel disease, and a left ventriculogram showed severe mitral regurgitation. The patient fell into cardiogenic shock after cardiac catheterization, and IABP was started. She underwent MAP and saphenous vein bypass grafting to the left anterior descending coronary artery and left circumflex coronary artery. Although the postoperative course was complicated by acute renal failure and respiratory dysfunction, the patient recovered from the operation and was discharged on the 137th postoperative day. Since the operative mortality of conventional valve replacement combined with CABG in ischemic mitral regurgitation has been high, we preferred MAP for this case.     

Intraaortic balloon pumping and emergency coronary arterial revascularization for acute myocardial infarction with impending extension

Seven patients had recurrent pain of myocardial ischemia and impending extension in the recovery phase of acute myocardial infarction. Six had institution of intraaortic balloon pump assistance (IABPA) with subsequent coronary arteriography, and all underwent revascularization. Two patients were in cardiogenic shock (CS), 3 had varying degrees of impairment in left ventricular function, and the remaining 2 were hemodynamically stable. The IABPA interrupted ischemic pain in all patients. Pain recurred in 4 with temporary interruption of IABPA. From one to three vein bypass grafts were constructed in each patient, and in 1 patient, infarctectomy also was carried out. Six of 7 patients recovered and are well. Temporary circulatory assistance with IABP, urgent coronary arteriography, and revascularization was shown to be effective therapy for postinfarction patients with impending extension.     

Enhanced intra-aortic balloon pump: markedly improved systemic hemodynamics and cardiac function in canines with severe,acute left ventricular failure

Intra-aortic balloon pumps (IABPs) cannot sustain hemodynamics if the left heart is severely injured. An enhanced IABP was evaluated in 6 anesthetized dogs with acute stenosis of the left anterior descending coronary artery, regional left ventricular (LV) stunning, and global LV dysfunction. An IABP balloon was inserted into the descending aorta and an external chamber containing another IABP balloon was connected to the aorta through a catheter inserted into the left subclavian artery. This emulated the enhanced IABP with a conduit from its external chamber passing axially through an internal IABP balloon. Compared to IABP, enhanced IABP improved hemodynamics and LV function in all conditions. During severe LV dysfunction and circulatory failure, IABP failed to augment diastolic aortic pressure or improve coronary and carotid flows. Enhanced IABP augmented diastolic pressure from 32 +/- 3 mm Hg to 87 +/- 2 mm Hg and increased coronary and carotid flows. Enhanced IABP may be a lifesaving device for patients with severe LV failure.     

Acute early postpartum cardiac failure associated with dilated cardiomyopathy: successful treatment with intra-aortic balloon counter-pulsation and levosimendan

The use of levosimendan (Simdax^®) was described in cases of acute cardiac failure in patients with peripartum cardiopmyopathy. We report the case of a 36 years old Philippine woman with an undiagnosed dilated myocardiopathy. She developed an acute severe left ventricular dysfunction in the early postpartum period after a cesarean section, possibly related to the recurrence of an unknown peripartum myocardiopathy. Due to failure of the conventional treatment with diuretics and inotropic support, an intra-aortic balloon with counter-pulsation was inserted. In rescue, treatment with levosimendan permitted to wean the patient from haemodynamic support, and a heart transplant was probably avoided. Three months later, a new echocardiography showed a persistent left ventricular dilation and a still marked alteration of left ventricular ejection fraction (28%).     

Mechanical Support for Postcardiotomy Heart Failure

Cardiac failure remains a life-threatening complication for certain patients undergoing intracardiac repair. Despite improvements in surgical techniques, methods of myocardial protection, and postoperative care, patients are frequently at risk to develop postoperative low output syndrome. Approximately 1% of cardiac surgical patients cannot be weaned from extracorporeal circulation in spite of adequate volume loading, the use of inotropic support, and initiation of intraaortic balloon pumping. In these cases, ventricular assist devices (VAD) can mechanically aid the failing heart and reverse the low output state. The concept of mechanical support for the failing left ventricle was first proposed by Clauss et al. in 1961. By 1968, Kantrowitz and associates had developed and refined the first intraaortic balloon pump (IABP). Through the efforts of Moulopolous and others, this device evolved into the present-day intraaortic balloon pump (IABP). Clinical evidence for the efficacy of left ventricular assist devices (LVAD) remained questionable until 1980, when the National Heart, Blood and Lung Institute evaluated short-term LVADs by comparing various types of mechanical aids. This report focused attention primarily on the failing left ventricle (LV). As the use of inotropic support, intraaortic balloon pumping, and LVADs improved, a small group of patients emerged who could not be separated from extracorporeal circulation due to a failing right ventricle. The failing right ventricle emerged as a unique clinical entity similar to postcardiotomy left ventricular failure that also benefited from mechanical cardiac assistance. Current therapy at major centers incorporating mechanical assist devices is based on the premise that the low output state will allow the failing heart to recover from a reversible injury. The frequent occurrence of postcardiotomy ischemia may be due to several factors such as poor myocardial protection, overdistension of the LV, emboli, coronary spasm or technical problems. Whatever the etiology, the end product of cardiac failure is a demand for oxygen consumption that cannot be met, thus leading to cardiac demise.     

Levosimendan: current status and future prospects

PURPOSE OF REVIEW: While patients with acute heart failure typically receive diuretics and vasodilators, contractile dysfunction and peripheral hypoperfusion also leads to a widespread use of inotropic agents despite the lack of evidence for efficacy or safety. Levosimendan, a calcium sensitizer and vasodilator, has been proposed to be superior to standard inotropes. In addition, further possible indications for levosimendan have been described, such as perioperative use, cardioprotection, cardiogenic shock, sepsis, and right ventricular dysfunction. RECENT FINDINGS: The mortality benefit of levosimendan has not been confirmed in two recent trials but the substance improves symptoms, decreases brain natriuretic peptide and is effective during beta-blocker treatment. The use of levosimendan as an add-on therapy in acute heart failure has been encouraged as well as its perioperative use. Levosimendan may also be useful during right ventricular dysfunction and septic shock due to its favorable effects on splanchnic perfusion. SUMMARY: Levosimendan is an established substance in the treatment of acute heart failure in several countries despite disappointing findings concerning a possible survival benefit in two recent clinical trials. Owing to its alternative mechanisms of action as compared with traditional cardiotonic agents, several promising clinical applications have arisen. Available evidence for the use of levosimendan in settings other than decompensated heart failure is currently limited.     

左西孟旦在心脏外科手术的应用

心脏外科手术中体外循环后心功能障碍的病人常需要正性肌力药物的支持.传统的正性肌力药由于存在增加心肌氧耗和致心律失常的危险,临床应用受到一定限制.左西孟旦,一种新型强心剂-钙增敏剂,其强心作用机制是增加心肌收缩蛋白对钙离子的敏感性,并通过激活KATP发挥扩血管和抗缺血效应.现有的临床资料表明左西孟旦在治疗术中高危或合并左心功能不全的心脏手术病人以及帮助病人顺利脱离体外循环方面具有很好的应用前景.     

Infarct exclusion for postinfarction left ventricular free wall rupture with severe congestive heart failure

A 70-year-old man was transferred to our hospital with severe congestive heart failure and ventricular arrhythmia due to acute myocardial infarction. He had experienced chest pain 3 weeks previously and was admitted to another hospital for dyspnea, where he required assist ventilation, 1 week prior to the transfer. An echocardiogram revealed a broad anteroseptal infarction and very poor left ventricular function with an ejection fraction (EF) of 22%. He remained in a severe congestive heart failure condition despite a full administration of catecholamines. Coronary angiogram findings revealed an occlusion of the proximal left anterior descending coronary artery and 1 week later severe hypotension was suddenly presented. An echocardiogram showed pericardial effusion with signs of cardiac tamponade. A pericardiocentesis was performed and hemodynamic improvement was obtained for a short time, after which the patient underwent urgent open heart surgery. During the operation, exclusion of the anteroseptal akinetic area using an oval patch was performed under a cardiopulmonary bypass and ventricular fibrillation. Severe cardiac failure remained postoperatively and the patient could not be weaned from cardiopulmonary bypass, therefore, we implanted a percutaneous cardiopulmonary support (PCPS) and started intraaortic balloon pumping (IABP). The patient was weaned from PCPS at 26 days after surgery and from IABP at 30 days. Following hospital release, he has continued to do well without heart failure for 39 months after the operation.     

Intraaortic balloon counterpulsation: its influence alone and combined with various pharmacological agents on regional myocardial blood flow during experimental acute coronary occlusion

We investigated the separate and combined effects of pharmacological and intraaortic balloon pump (IABP) support on regional myocardial blood flow in an experimental model of acute myocardial ischemia. Chloralose-anesthetized dogs were ventilated with an oxygen-air mixture, and cardiac output, arterial pressure, and heart rate were held constant. Treatment was begun 20 minutes following permanent ligation of the left anterior descending coronary artery (LAD). We evaluated the following pharmacological interventions: 25% hypertonic mannitol, isosorbide dinitrate, methyl-prednisolone sodium succinate, and propranolol. We measured left ventricular hemodynamics and intramyocardial blood flow by the radioactive microsphere technique prior to treatment and at 15-minute intervals thereafter. Compared with control measurements 20 minutes following LAD ligation, collateral blood flow to ischemic myocardium tended to decrease with no treatment. Treatments with the four pharmacological interventions and with IABP alone produced no significant improvement in collateral blood flow to ischemic myocardium 15 minutes following treatment. In contrast, mannitol, isosorbide dinitrate, and propranolol, each combined with IABP support, produced significant improvements in collateral flow within the same time periods. In nonischemic myocardium, combined pharmacological and IABP treatment did not enhance myocardial blood flow above that obtained with the pharmacological agents alone. The most effective combination of mechanisms for improving the ischemic region's myocardial blood flow appeared to be a reduction of extravascular coronary flow resistance coupled with a simultaneous increase in diastolic arterial pressure.     

A case of acute right ventricular infarction and life-saving right ventricular assistance following emergency coronary revascularization and resection of a left ventricular aneurysm--discussion of indication and proper assist flow volume]

Right ventricular assistance (RVA) using centrifugal pump in combination with IABP was used to treat a patient who was difficult to wean from a cardiopulmonary bypass following emergency coronary revascularization and resection of a ventricular aneurysm performed to treat acute right ventricular infarction due to a PTCA complication. After 131 hours of RVA at 3.2 to 4.8 l/min, it was possible to remove the pump. No heparin was administered during this time, changing the pump head twice, was used for 64 and 50 hour period, no thrombi were detected either time. After being weaned from RVA, the patient developed severe respiratory dysfunction, but on the 10th postoperative day (POD) IABP was weaned, and on the 13th POD the artificial respirator was withdrawn. The results of the postoperative cardiac catheterization were favorable, the patient was discharged on the 57th POD, and has returned to society at the present time. The indications for RVA include a central venous pressure > 20 mmHg and a cardiac index < 1.8 l/min/m2, and tissue perfusion pressure and general preoperative condition should severe as guides. The higher the assisted flow volume the more efficacious in relieving ventricular load, but, since there is a limit to how much the left ventricle and lungs can withstand, it should not exceed levels which ensure the maintainance of cardiac output and tissue perfusion pressure.     

A Novel Subcutaneous Counterpulsation Device: Acute Hemodynamic Efficacy During Pharmacologically Induced Hypertension,Hypotension, and Heart Failure

The miniaturization of mechanical assist devices and less invasive implantation techniques may lead to earlier intervention in patients with heart failure. As such, we evaluated the effectiveness of a novel, minimally invasive, implantable counterpulsation device (CPD) in augmenting cardiac function during impaired hemodynamics. We compared the efficacy of a 32‐mL stroke volume CPD with a standard 40‐mL intra‐aortic balloon pump (IABP) over a range of clinically relevant pathophysiological conditions. Male calves were instrumented via thoracotomy, the CPD was anastomosed to the left carotid artery, and the IABP was positioned in the descending aorta. Hemodynamic conditions of hypertension, hypotension, and heart failure were pharmacologically simulated and data were recorded during CPD and IABP support (off, 1:2, 1:1 modes) for each condition. In all three pathophysiological conditions, the CPD and IABP produced similar and statistically significant (P < 0.05) increases in coronary artery blood flow normalized to the left ventricular (LV) workload. During hypotension and heart failure conditions, however, the CPD produced significantly greater reductions in LV workload and myocardial oxygen consumption as compared with the IABP. A novel 32‐mL CPD connected to a peripheral artery produced equivalent or greater hemodynamic benefits than a standard 40‐mL IABP during pharmacologically induced hypertension, hypotension, and heart failure conditions.     

Case of epicardial left ventricular pacing lead implantation under general anesthesia in a patient with severe cardiac dysfunction

An 82-year-old man with severe cardiac dysfunction due to ischemic cardiac myopathy was diagnosed as indication for biventricular pacing. His left ventricular ejection fraction was 22%. Because of difficulty in coronary sinus lead fixation, epicardial lead implantation through a thoracotomy under general anesthesia was scheduled. Intraaortic balloon pumping (IABP) was started prior to the operation. Anesthesia was induced by midazolam and fentanyl, and maintained with fentanyl and low dose propofol infusion. Milrinone was infused throughout the operation. Except for just after the anesthesia induction, systolic blood pressure was kept well around 100 mmHg. The operation was completed without any ploblems. NYHA classification improved markedly (class IV to class II) by biventricular pacing. Using IABP, we could maintain blood pressure and stabilize hemodynamics during left ventricular lead implantation in a patient with severe heart failure.     

外置主动脉旁反搏装置对急性心衰的辅助效果

目的 探讨外置主动脉旁反搏装置(out-thoracic paraaortic counterpulsation device,OTPACD)对急性心衰的辅助效果。方法 选成年绵羊8只,将自制OTPACD(每搏量60 ml)的无瓣人工血管吻合于降主动脉,反搏泵放置于胸外。同时于降主动脉内置入IABP球囊(容量40ml)。结扎冠状动脉分支建立急性心衰动物模型,随机采用OTPACD或IABP进行反搏辅助。记录心衰前后和采用不同辅助方法后实验动物血流动力学指标。结果 IABP和OTPACD辅助后,实验动物心输出量增加13.46％(P=0.002)和17.79％ (P=0.000),二者相比,P=0.803;舒张期平均动脉压分别增高为15.01％ (P =0.003)和29.48％ (P =0.000),二者相比,P=0.001。IABP和OTPACD辅助后左室舒张末压分别降低为15.79％ (P =0.002)和35.09％ (P =0.001),二者相比,P=0.004;左侧颈动脉流量分别增加6.70％ (P =0.003)和14.52％(P=0.001),二者相比,P=0.006。结论 IABP对急性心衰动物有良好的辅助作用,而OTPACD进一步增加了心输出量,提高了舒张期平均动脉压,降低了左心室舒张末压,改善心脏功能,增加脑部灌注,对急性心衰辅助效果优于IABP。     

Levosimendan in cardiac surgery: current best available evidence

Recent upsurge in referral of patients with high perioperative risk or compromised left ventricular function for cardiac surgery has lead to an increasing use of pharmacologic support in the form of vasodilator and inotropic therapy to achieve improvement of tissue perfusion in the perioperative period or to support weaning from cardiopulmonary bypass. Traditionally, perioperatively used inotropic agents, epinephrine, dobutamine, and milrinone, are limited by significant increases in myocardial oxygen consumption, proarrhythmia, or neurohormonal activation. Levosimendan, a new inodilator for the treatment of decompensated heart failure, has also shown promise in elective therapy of cardiac surgical patients with high perioperative risk or compromised left ventricular function, as well as in rescue therapy of patients with difficult weaning from cardiopulmonary bypass. This review article briefly discusses the pharmacology of levosimendan and evaluates current best available evidence to assess the safety and efficacy of levosimendan usage in cardiac surgery.     

Emergency aortocoronary bypass grafting

We evaluated operative results of emergency aortocoronary bypass grafting in 17 patients (surgical group) with impending myocardial infarction or acute myocardial infarction, and compared them to those of medical therapy in 16 patients (medical group) required IABP with same condition. Mortality in surgical group is significantly lower than that in medical group. In patients with severe coronary artery disease, mortality in surgical group is significantly lower than that in medical group. In patients with severe left ventricular dysfunction, mortality in surgical group is significantly lower than that in medical group. The period using IABP before the operation in expired patients is longer than that in survived patients. These data indicate that emergency operation should be performed immediately after IABP in patients with severe coronary artery disease or severe left ventricular dysfunction.     

Improved efficacy of intra-aortic balloon pumping by pharmacological myocardial protection for postoperative pump failure after coronary revascularization

Fifty patients took part in a randomized and prospective study to define the effect of pharmacological myocardial protection when using IABP in patients with postoperative pump failure, following coronary revascularization under cardiopulmonary bypass employing moderate hypothermia and cardioplegia. Pharmacological protection was given to 23 patients, administering coenzyme Q, 5 mg/kg, and aprotinin, 10,000 KIU/kg, intravenously, every 12 hours, following surgery. A single dose of each drug was also given intraoperatively. The postoperative haemodynamics, serum enzyme levels and success of weaning from IABP, were compared between the group of patients who received pharmacological protection (the treated group) and the control group which comprised 27 patients who were treated only with IABP. Among the surviving patients, no significant differences were seen in the hemodynamics or cardiac enzyme levels between the two groups. The rate of successful weaning from IABP however, was 95 per cent in the treated group as compared with only 74 per cent in the control group, p=0.02. These results suggest that pharmacological myocardial protection, using coenzyme Q and aprotinin in both the intra- and post-operative periods, improves the efficacy of IABP in the treatment of post-operative pump failure following coronary revascularization. This paper was presented at the Xth World Congress of Cardiology at Washington, DC in 1986.