Multivariate statistical evaluation of intraaortic counterpulsation in pump failure complicating acute myocardial infarction

Intra-aortic balloon pump postcardiac surgery: A literature review

Intra-aortic balloon pump (IABP) has been the most commonly used mechanical assist circulatory device in many postcardiotomy low output disorders for decades. Mechanism of IABP is based on its inflation in time of the diastolic pressure in the aortic root resulting increase in the blood and oxygen amount of the coronary artery and its deflation in left ventricular afterload during the systolic period. Prophylactic and postoperative application of IABP has been suggested by researchers, which has been commonly used in high-risk patients undertaking coronary artery bypass grafting surgery or percutaneous coronary intervention. Other researchers put forward the idea of the percutaneous IABP insertion throughout the left axillary artery as a reliable and relatively well-tolerated approach and also as a recovery tool to bridge patients with end-stage heart failure to heart transplantation. The current review was aimed to give further insight into routine IABP application by presenting the basic principles and trends in the incidence, management, role of IABP recovery, and long-lasting mortality outcomes in patients with cardiovascular disorders and discussing previous and current evidence.

Haemodynamic patterns in ST-elevation myocardial infarction: incidence and correlates of elevated filling pressures

OBJECTIVES.: We sought to study the incidence and clinical correlates of elevated filling pressures in ST-elevation myocardial infarction (STEMI) patients, without physical signs of heart failure and treated with primary coronary angioplasty. BACKGROUND.: Haemodynamic data, as measured with a Swan-Ganz catheter, are not routinely obtained in STEMI patients. At admission, low blood pressure, increased heart rate, sweating, increased respiration rate, rales, oedema, and a third heart sound are indicative of heart failure. METHODS.: All consecutive STEMI patients were monitored by a Swan-Ganz catheter and central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), pulmonary artery pressure (PAS) and cardiac index (CI) were measured. To investigate the clinical correlates of the haemodynamic status patients were classified according to previously defined haemodynamic criteria. RESULTS.: We studied 90 patients, aged 60.5+/-13.1 year, 76% were male. Mortality at 30 days was 2/90 (2.2%). Patients with impaired haemodynamics presented later and had larger myocardial infarct sizes. CVP, PCWP and PAS were above normal in 36 (40%) patients. CONCLUSION.: A large proportion of STEMI patients without physical signs of heart failure have elevation of right- as well as left-sided cardiac filling pressures. (Neth Heart J 2007;15:95-9.).

Immediate and long-term survival after intra-aortic balloon pumping: is advanced age an independent, unfavorable prognostic factor?

OBJECTIVE

To determine whether advanced age is an independent prognostic factor that may increase the risk of complications and reduce the immediate and long-term survival after treatment with intra-aortic balloon pumping (IABP) for acute ischemic heart disease.

DESIGN

Retrospective analysis of a clinical series and long-term follow-up study.

PATIENTS

A total of 142 patients (age range 23-86 years) in whom IABP was indicated following a standardized protocol.

MEASUREMENTS

Univariate analysis of the association between age and anamnestic, clinical, and hemodynamic data significantly affecting prognosis; multivariate logistic regression analysis of variables showing significant associations.

RESULTS

IABP-related complications were independent of age. At univariate analysis, pre-existing, noncardiac, associated conditions (chronic renal failure, stroke, bronchopulmonary disease) (P < .001), an indication to IABP for hemodynamic complications of acute myocardial infarction rather than for medically refractory myocardial ischemia (P < .001), a lack in hemodynamic response to IABP (P < .002), a prolonged delay to IABP initiation (P < .003), and advanced age (P < .025) were all predictors of in-hospital mortality. However, older patients were also more frequently affected by chronic comorbid conditions and by acute left ventricular failure as an indication to IABP. When these variables were entered into logistic regression models, the association between age and mortality was no longer statistically significant. Similarly, advancing age was associated (P < .012) with an increased mortality rate during an average follow-up of 94 +/- 9 months, but, again, such a significant association disappeared when simultaneously adjusting for New York Heart Association functional class, which was the single most important predictor of long-term mortality.

CONCLUSIONS

Several anamnestic and clinical variables, rather than advanced age itself, are independent, prognostic factors negatively affecting the outcome of treatment with IABP. Technique-related complications are independent of age. Thus, old age should not be considered as a criterion to exclude any patient, a priori, from the potential benefits of this type of cardiocirculatory assistance.

Effect of protracted dobutamine infusion on survival of patients in cardiogenic shock treated with intraaortic balloon pumping

The survival of subjects with postmyocardial infarction cardiogenic shock treated with intra-aortic balloon pumping (IABP) differs significantly among various reports. Differences in the criteria for IABP application and in the timing of its initiation have been considered as the main reasons for variations in survival. This study examines whether the way patients in cardiogenic shock are treated prior to IABP may affect their survival. Fifty-five patients in severe postmyocardial infarction cardiogenic shock were classified into three groups according to the rate of dobutamine infusion prior to IABP: the "nondobutamine" (group A, n = 31), the "high-dose dobutamine" (8 to 20 micrograms.kg-1.min-1, group B, n = 17), and the "low-dose dobutamine" (up to 7 micrograms.kg-1.min-1, group C, n = 7). All subjects seen from 1978 to 1983 were recruited for group A, from 1986 to 1990 for group B, and in years 1984, 1985, and 1991 for group C, without using any other classification criteria. It was shown a posteriori that the three groups did not differ in the features of the subjects, in the severity of shock, and in the time length between onset of shock and pumping initiation. None of the 17 subjects of group B could survive under pumping, while 10 of the 31 subjects in group A and 4 of the 7 subjects in group C were weaned off pumping.

CONCLUSIONS

A protracted, high-dose pre-IABP administration of dobutamine may adversely affect the survival of patients with postmyocardial infarction cardiogenic shock.

Evaluation of an extraaortic counterpulsation device in severe cardiac failure

A valveless, single-orifice polyurethane ventricle with a maximum stroke volume of 60 mL was implanted on the brachiocephalic artery just above the aortic arch in sheep (n = 14) to act as an extraaortic counterpulsation device. In parallel, an intraaortic balloon was placed in the descending thoracic aorta. Both devices were pneumatically driven with an intraaortic balloon pump console that was gated by the electrocardiogram to provide aortic diastolic augmentation at a stroke volume of 40 mL. To compare the efficacy of counterpulsation for each device during severe cardiac failure, biventricular block was induced by continuous infusion of esmolol (100 to 600 micrograms.kg-1.min-1), titrated to reduce aortic flow and pressure to less than 75% of baseline. Pulsatile coronary and aortic flows were recorded with ultrasonic flow probes placed around their respective vessels. Aortic root and left ventricular pressures were recorded using micromanometers. The enhancement of hemodynamic variables for both devices were compared for optimal timing conditions, which were defined as inflation set just before the dicrotic notch and deflation bordering on isovolumetric systole. The extraaortic counterpulsation device was able to significantly augment aortic and coronary flows while simultaneously decreasing left ventricular tension time index and aortic end-diastolic pressure (p less than 0.02). The intraarotic balloon pump was able to significantly reduce only tension time index (p less than 0.002) to a lesser extent that the extraaortic counterpulsation device. All analysis was performed with the paired-samples t test. The extraaortic counterpulsation device greatly improves the myocardial oxygen supply-consumption ratio of the left ventricle by increasing diastolic coronary flow and reducing left ventricular wall tension during systole.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanical assistance in cardiogenic shock

Cardiogenic shock following myocardial infarction or surgical interventions with extracorporeal circulation, not responding to conventional treatment, is an "intractable" condition, unless mechanical assistance is applied. In today's practice mechanical assistance consists in counterpulsating an intraaortic balloon or, if this does not improve the condition, in using a left ventricle bypassing pump. In spite of the complexity of the procedures and the complications, a number of patients can recover with or without a subsequent corrective intervention or heart transplantation. The need for developing systems for chronic assistance to non-correctable hearts and the difficulties of the endeavour are pointed out.

Comparison of an implanted abdominal aortic counterpulsation device with the intraaortic balloon pump in a heart failure model

The abdominal aortic counterpulsation device is a round pumping chamber with a valveless opening which is implanted retroperitoneally on the abdominal aorta. The Utah driver is connected to the device through an air conduit and is synchronized on the electrocardiographic signal to provide diastolic aortic augmentation. For comparison an intraaortic balloon was also driven by the Utah driver system. The abdominal aortic counterpulsation device (stroke volume = 30, 40 and 60 ml) and the intraaortic balloon pump (balloon volume = 20 ml) were tested in dogs with acute left ventricular failure. The abdominal aortic counterpulsation device was also tested in normal animals. In acute left ventricular failure the abdominal aortic counterpulsation device at a stroke volume of 30, 40 or 60 ml decreased left ventricular end-diastolic pressure by an average of 28.56 (p less than 0.001), 39.56 (p less than 0.001) and 44.14% (p less than 0.005), respectively; aortic end-diastolic pressure by 24.11 (p less than 0.001), 26.67 (p less than 0.001) and 19.57% (p less than 0.01); and aortic systolic pressure by 18.56 (p less than 0.002), 26.0 (p less than 0.001) and 22.43% (p less than 0.005). It increased cardiac index by 27.58 (p less than 0.02), 35.59 (p less than 0.005) and 43.42% (p less than 0.001) and it provided peak aortic diastolic augmentation of 64.5 (p less than 0.001), 69.78 (p less than 0.001) and 74.43% (p less than 0.001), respectively, above the control aortic end-diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical experience with intra-aortic balloon counterpulsation in 112 consecutive patients

Intra-aortic balloon pumping (IABP) was attempted in 112 consecutive patients, resulting in successful placement in 49 of 50 (98%) patients when the percutaneous technique was used and in 60 of 62 (97.3%) patients when the surgical technique was used. Complications following acute myocardial infarction and perioperative problems were the two most frequent (47% and 52%, respectively) indications for IABP. A favorable survival was observed in patients with acute myocardial infarction with ventricular septal defect undergoing surgery after IABP (80%) and in patients in whom IABP was used in the perioperative setting (57.6%); survival remained poor in patients with postinfarction shock or severe heart failure (20% and 23%, respectively). Complications related to IABP occurred in 23 (20.5% patients but tended to occur more frequently in patients undergoing placement by the percutaneous route than by the surgical route (31% vs 9.6%; p less than 0.03) and in patients over age 70. Thus IABP can be successfully inserted in the majority of patients, but the high complication rate, especially with the percutaneous route, suggests caution in its indiscriminate use, particularly in patients whose mortality remains high despite its use.