Regional and global left ventricular function during intra-aortic balloon counterpulsation in patients with acute myocardial infarction shock

Efficacy of Subcutaneous Electrocardiogram Leads for Synchronous Timing During Chronic Counterpulsation Therapy

Counterpulsation devices (CPDs) require an accurate, reliable electrocardiogram (ECG) waveform for triggering inflation and deflation. Surface electrodes are for short-term use, and transvenous/epicardial leads require invasive implant procedure. A subcutaneous ECG lead configuration was developed as an alternative approach for long-term use with timing mechanical circulatory support (MCS) devices. In this study, efficacy testing was completed by simultaneously recording ECG waveforms from clinical-grade epicardial (control) and subcutaneous (test) leads in chronic ischemic heart failure calves implanted with CPD for up to 30 days. Sensitivity and specificity of CPD triggering by R-wave detection was quantified for each lead configuration. The subcutaneous leads provided 98.9% positive predictive value and 98.9% sensitivity compared to the epicardial ECG leads. Lead migration (n = 1) and fracture (n = 1) were observed in only 2 of 40 implanted leads, without adversely impacting triggering efficacy due to lead redundancy. These findings demonstrate the efficacy of subcutaneous ECG leads for long-term CPD timing and potential use as an alternative method for MCS device timing.

Intra-aortic balloon pump counterpulsation (IABP) for myocardial infarction complicated by cardiogenic shock

BACKGROUND

Intra-aortic balloon pump counterpulsation (IABP) is currently the most commonly used mechanical assist device for patients with cardiogenic shock due to acute myocardial infarction. Although there has been only limited evidence from randomised controlled trials, the previous guidelines of the American Heart Association/American College of Cardiology (AHA/ACC) and the European Society of Cardiology (ESC) strongly recommended the use of the IABP in patients with infarction-related cardiogenic shock on the basis of pathophysiological considerations, non-randomised trials and registry data. The recent guidelines downgraded the recommendation based on a meta-analysis which could only include non-randomised trials showing conflicting results. Up to now, there have been no guideline recommendations and no actual meta-analysis including the results of the large randomised multicentre IABP-SHOCK II Trial which showed no survival benefit with IABP support. This systematic review is an update of the review published in 2011.

OBJECTIVES

To evaluate, in terms of efficacy and safety, the effect of IABP versus non-IABP or other assist devices guideline compliant standard therapy on mortality and morbidity in patients with acute myocardial infarction complicated by cardiogenic shock.

SEARCH METHODS

Searches of CENTRAL, MEDLINE (Ovid) and EMBASE (Ovid), LILACS, IndMed and KoreaMed, registers of ongoing trials and proceedings of conferences were updated in October 2013. Reference lists were scanned and experts in the field contacted to obtain further information. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials on patients with acute myocardial infarction complicated by cardiogenic shock.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were performed according to the published protocol. Individual patient data were provided for six trials and merged with aggregate data. Summary statistics for the primary endpoints were hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs).

MAIN RESULTS

Seven eligible studies were identified from a total of 2314 references. One new study with 600 patients was added to the original review. Four trials compared IABP to standard treatment and three to other percutaneous left assist devices (LVAD). Data from a total of 790 patients with acute myocardial infarction and cardiogenic shock were included in the updated meta-analysis: 406 patients were treated with IABP and 384 patients served as controls; 339 patients were treated without assisting devices and 45 patients with other LVAD. The HR for all-cause 30-day mortality of 0.95 (95% CI 0.76 to 1.19) provided no evidence for a survival benefit. Different non-fatal cardiovascular events were reported in five trials. During hospitalisation, 11 and 4 out of 364 patients from the intervention groups suffered from reinfarction or stroke, respectively. Altogether 5 out of 363 patients from the control group suffered from reinfarction or stroke. Reocclusion was treated with subsequent re-revascularization in 6 out of 352 patients from the intervention group and 13 out of 353 patients of the control group. The high incidence of complications such as moderate and severe bleeding or infection in the control groups has to be attributed to interventions with other LVAD. Possible reasons for bias were more frequent in small studies with high cross-over rates, early stopping and the inclusion of patients with IABP at randomisation.

AUTHORS' CONCLUSIONS

Available evidence suggests that IABP may have a beneficial effect on some haemodynamic parameters. However, this did not result in survival benefits so there is no convincing randomised data to support the use of IABP in infarct-related cardiogenic shock.

Off pump repair of left ventricular rupture following mitral valve replacement: The crucial assistance of the IntraAortic Balloon Pump

INTRODUCTION

Left ventricular (LV) rupture is a not as frequent, but potentially lethal complication of mitral valve replacement or repair.

PRESENTATION OF CASE

We report a case of a 67-year-old man who underwent mitral valve replacement and Cox Maze IV procedure. A massive bleed from the LV rupture was noted postoperatively while the patient was extubated. The control of bleeding was impossible until an IntraAortic Balloon Pump (IABP) was inserted. A bovine pericardial patch was applied, overlapping an extensive epicardial area, perimetrically of the hematoma. Between the epicardium and the pericardial patch we applied an autologous fibrin sealant.

DISCUSSION

The off-pump technique used to repair the LV rupture after a MVR, is more feasible when the patient is supported by an IABP that subsequently decreases the tension of the myocardial suture site.

CONCLUSION

The IABP, is a necessary device, that decreases the tension along the suture site post a left ventricular rupture following a MVR.

Intra-aortic balloon pump counterpulsation (IABP) for myocardial infarction complicated by cardiogenic shock

BACKGROUND

Intra-aortic balloon pump counterpulsation (IABP) is currently the most commonly used mechanical assist device for patients with cardiogenic shock due to acute myocardial infarction.Although there is only limited evidence by randomised controlled trials, the current guidelines of the American Heart Association/American College of Cardiology and the European Society of Cardiology strongly recommend the use of the intra-aortic balloon counterpulsation in patients with infarction-related cardiogenic shock on the basis of pathophysiological considerations as also non-randomised trials and registry data.   

OBJECTIVES

To determine the effect of IABP versus non-IABP or other assist devices guideline compliant standard therapy, in terms of efficacy and safety, on mortality and morbidity in patients with acute myocardial infarction complicated by cardiogenic shock.

SEARCH STRATEGY

Searches of CENTRAL, MEDLINE and EMBASE, LILACS, IndMed and KoreaMed, registers of ongoing trials and proceedings of conferences were conducted in January 2010, unrestricted by date. Reference lists were scanned and experts in the field contacted to obtain further information. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials on patients with myocardial infarction complicated by cardiogenic shock.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were performed according to a published protocol. Individual patient data were provided for five trials and merged with aggregate data. Summary statistics for the primary endpoints were hazard ratios (HR's) and odds ratios with 95% confidence intervals (CI).

MAIN RESULTS

Six eligible and two ongoing studies were identified from a total of 1410 references. Three compared IABP to standard treatment and three to percutaneous left assist devices (LVAD). Data from a total of 190 patients with acute myocardial infarction and cardiogenic shock were included in the meta-analysis: 105 patients were treated with IABP and 85 patients served as controls. 40 patients were treated without assisting devices and 45 patients with LVAD. HR's for all-cause 30-day mortality of 1.04 (95% CI 0.62 to 1.73) provides no evidence for a survival benefit. While differences in survival were comparable in patients treated with IABP, with and without LVAD, haemodynamics and incidences of device related complications show heterogeneous results.

AUTHORS' CONCLUSIONS

Available evidence suggests that IABP may have a beneficial effect on the haemodynamics, however there is no convincing randomised data to support the use of IABP in infarct related cardiogenic shock.

Intra-aortic balloon counterpulsation for the treatment of myocardial infarction complicated by acute severe heart failure

Intractable heart failure (HF) remains a leading fatal complication of acute myocardial infarction (AMI). Intra-aortic balloon pump (IABP) counterpulsation assists the failing left ventricle and accelerates the functional recovery of stunned myocardium. Despite its remarkable performance, the beneficial effects of the IABP in the setting of acute HF or cardiogenic shock complicating AMI have not been confirmed in a randomized clinical trial. Instead, large amounts of information have been collected in observational studies or in retrospective analyses of randomized trials of reperfusion strategies in patients with AMI. The strategy of "stabilize with IABP, treat with reperfusion, and transfer for complete revascularization" has, thus far, yielded the best outcomes, and every effort should be made to implement this strategy in all patients presenting with AMI and severe HF.

Acute hemodynamic efficacy of a 32-ml subcutaneous counterpulsation device in a calf model of diminished cardiac function

The acute hemodynamic efficacy of an implantable counterpulsation device (CPD) was evaluated. The CPD is a valveless single port, 32-ml stroke volume blood chamber designed to be connected to the human axillary artery using a simple surface surgical procedure. Blood is drawn into the pump during systole and ejected during diastole. The acute hemodynamic effects of the 32-ml CPD were compared to a standard clinical 40-ml intra-aortic balloon pump (IABP) in calves (80 kg, n = 10). The calves were treated by a single oral dose of Monensin to produce a model of diminished cardiac function (DCF). The CPD and IABP produced similar increases in cardiac output (6% CPD vs. 5% IABP, p > 0.5) and reduction in left ventricular external work (14% CPD vs. 13% IABP, p > 0.5) compared to DCF (p < 0.05). However, the ratio of diastolic coronary artery flow to left ventricular external work increase from DCF baseline (p < 0.05) was greater with the CPD compared to the IABP (15% vs. 4%, p < 0.05). The CPD also produced a greater reduction in left ventricular myocardial oxygen consumption from DCF baseline (p < 0.05) compared to the IABP (13% vs. 9%, p < 0.05) despite each device providing similar improvements in cardiac output. There was no early indication of hemolysis, thrombus formation, or vascular injury. The CPD provides hemodynamic efficacy equivalent to an IABP and may become a therapeutic option for patients who may benefit from prolonged counterpulsation.

Evaluation of effects of intra aortic balloon counterpulsation on autonomic nervous system functions by heart rate variability analysis

BACKGROUND

In patients with acute myocardial infarction (AMI), intraaortic balloon counterpulsation (IABC) may improve cardiac performance, decrease the incidence of recurrent ischemia, and improve survival. Although there have been several reports concerning circulatory maintenance with the IABC, response of the autonomic nervous system to these hemodynamic changes is not clear. Heart rate variability (HRV) analysis has been extensively used to evaluate autonomic modulation of sinus node and to identify patients at risk for an increased cardiac mortality. In this study, we evaluated effects of the IABC on autonomic nervous system functions by HRV analysis.

METHODS

The study group was composed of 32 consecutive patients (13 female, 19 male aged 61.8 +/- 8.8 years) undergoing IABC. Transthoracic echocardiography and 1-hour Holter recordings for HRV analysis in each IAB pumping mode were obtained.

RESULTS

The IABC improved left ventricular diastolic and systolic functions as well as caused an increase in SDNN1, PNN50(1), RMSSD1, and HF1 and a decrease in LF1, LF/HF1, mean heart rate, and the number of ventricular extrasystoles. The improvements in HRV parameters were correlated with some hemodynamic changes such as the increase in MAP and CO during counterpulsation. The only independent factors affecting in-hospital mortality were the change in LF/HF1 ratio (DeltaLF/HF1) and the change in the number of ventricular extrasystole (DeltaVES). The decrease in LF/HF1 > or = 4.9 decreased the mortality by 1.7-folds (RR = 0.6, P = 0.04, 95% CI: 0.1-2.3). The decrease in VES > or = 27/15 minutes resulted in mortality reduction by 16-folds (RR = 0.06, P = 0.02, 95% CI: 0.01-0.4).

CONCLUSIONS

As a result, the IABC, especially in 1:1 support, causes an increase in HRV, decrease in sympathetic overactivity, and improvement in sympathovagal balance besides the favorable hemodynamic changes, and these electrophysiologic changes may explain the role of the IABC in the treatment of ventricular arrhythmias.

Intra-aortic balloon counterpulsation

Intra-aortic balloon counterpulsation (IABP) is sometimes used in critically ill patients with cardiac disease. By increasing diastolic arterial pressure and decreasing systolic pressure, it reduces left ventricular afterload. IABP may be beneficial in subjects with cardiogenic shock, mechanical complications of myocardial infarction, intractable ventricular arrhythmias, or advanced heart failure or those who undergo "high-risk" surgical or percutaneous revascularization, but the evidence to support its use in these patient groups is largely observational. Contraindications to IABP include severe peripheral vascular disease as well as aortic regurgitation, dissection, or aneurysm. The potential benefits of IABP must be weighed against its possible complications (bleeding, systemic thromboembolism, limb ischemia, and, rarely, death).

Basic Principles of the Intraaortic Balloon Pump and Mechanisms Affecting Its Performance

The intraaortic balloon pump (IABP) is the single most effective and widely used device for temporary mechanical assistance of the failing heart. Although the principles underlying IABP function are simple, various biologic factors often determine its performance in a particularly complicated way. We briefly describe the basic disciplines of counterpulsation by IABP and the induced hemodynamic changes while clarifying the biologic mechanisms that play a crucial role in the modification of IABP acute hemodynamic performance.

Short-term effects of intra-aortic balloon pumping on renal blood flow and renal oxygen consumption in cardiogenic shock

Intra-aortic balloon pumping is frequently used in patients with cardiogenic shock when oliguria persists despite maximal pharmacologic support. The objective of this study was to measure the effect of intra-aortic balloon pumping on renal blood flow, renal oxygen delivery, and renal oxygen consumption in such patients. Central hemodynamics, renal blood flow, and oxygen transport were measured in 10 patients in low cardiac output states. Measurements were made with and without intra-aortic balloon counterpulsation. Renal blood flow was measured by continuous renal vein thermodilution. Small improvements were observed in cardiac output (3.1 +/- 0.8 vs 3.5 +/- 0.8 L/min, P < .01) and pulmonary capillary wedge pressure (22 +/- 5.6 vs 19 +/- 5.3 mmHg, P < .05), but mean arterial blood pressure was unchanged (69 +/- 11 vs 69 +/- 5 mmHg, not significant). Baseline renal blood flow was reduced to approximately 37%, renal oxygen delivery to 31%, and renal oxygen consumption to 60% of normal values. No significant improvement was seen in single-kidney renal blood flow (184 +/- 108 vs 193 +/- 107 mL/min), renal oxygen delivery (28 +/- 16 vs 30 +/- 16 mL/min), or renal oxygen consumption (4.9 +/- 2.0 vs 4.7 +/- 2.5 mL/min) in response to 1:1 counterpulsation. In comparison with measurements made during short-term suspension of counterpulsation, 1:1 aortic balloon pumping failed to result in an increase in renal blood flow, oxygen delivery, or oxygen consumption from the low levels observed in these patients.

Transesophageal echocardiographic evaluation of left ventricular function during intraaortic balloon pump counterpulsation

Transesophageal echocardiography was used to study the effects of intraaortic balloon pump counter pulsation (IABP) on left ventricular dimensions and function in 16 hypotensive patients after cardiac surgery. The short-axis cross section at midpapillary muscle level was used to determine systolic and diastolic dimensions. We found a significant decrease in end-systolic and end-diastolic area and increase in fractional area change during IABP-supported circulation. Regional area ejection fraction analysis demonstrated an improvement during IABP of impaired (particularly severely impaired) function at baseline. We conclude that both regional and global left ventricular function improve by the use of IABP in conjunction with a decrease of left ventricular size.

Myocardial infarct size can be estimated from serial plasma myoglobin measurements within 4 hours of reperfusion

BACKGROUND

An early estimation of infarct size is useful for the appropriate early treatment of patients with acute myocardial infarction. We evaluated how early and how accurately infarct size could be estimated from serial plasma myoglobin (Mb) measurements in patients with successful reperfusion.

METHODS AND RESULTS

We measured plasma Mb and creatine kinase (CK) in 35 patients in whom reperfusion therapy was successfully performed. Blood samples were collected at 15-minute intervals for 2 hours after reperfusion, at 30-minute intervals for the subsequent 2 hours, and at 3-6-hour intervals until 52 hours after reperfusion. Plasma Mb was measured by a newly developed turbidimetric latex agglutination assay. Total Mb and CK release (sigma Mb, sigma CK) were calculated with a one-compartment model. The mean chord motion in the most hypokinetic 50% of the infarct-related artery territory was calculated from follow-up ventriculograms as an index of the severity of regional hypokinesis. There were significant correlations between sigma Mb and sigma CK (r = 0.89), between log sigma Mb and the severity of regional hypokinesis (r = -0.85), and between log sigma CK and the severity of regional hypokinesis (r = -0.74). The time required for the cumulative Mb release curves to reach a plateau was 64 +/- 28 minutes. An additional 53 +/- 14 minutes was required to calculate the disappearance rate constant of Mb, and 15 minutes was necessary for the assay. Therefore, the total time required for sigma Mb to be available was 132 +/- 40 minutes, significantly shorter than the time required for sigma CK, 24.3 +/- 9.1 hours (p < 0.001). The infarct size could be estimated from the sigma Mb in 34 of 35 patients within 4 hours of reperfusion.

CONCLUSIONS

Infarct size can be estimated accurately 4 hours after reperfusion by calculating the sigma Mb in patients with successful reperfusion.

Effects of intraaortic balloon pumping on mitral flow dynamics in patients with coronary artery bypass operations

We evaluated the improvement in left ventricular function in 26 patients after coronary artery bypass grafting who were treated with intraaortic balloon pumping (IABP). Mitral flow velocity-time integral in the rapid filling phase (IntR) and that in the atrial contraction phase (IntA), the sum of IntR and IntA (IntR+IntA), and the ratio of IntA to IntR (IntA/IntR) were calculated with patients on and off balloon pumping (IABP ON-OFF test). IABP increased IntR and IntR+IntA, decreased IntA/IntR, and did not change IntA, suggesting that a decreased afterload or augmented coronary perfusion improves left ventricular relaxation. When the balloon inflated on every other beat (IABP 1:2 test), IntR and IntR+IntA increased without balloon assist, IntA/IntR decreased off IABP, and IntA did not change. The afterload reduction or augmented coronary perfusion on the previous beat with IABP might help ventricular filling on the next beat without balloon assist. A drastic decrease in IntR after IABP stopped indicated the need to continue IABP. Since the change in IntR during IABP ON-OFF test was significantly correlated with that in IntR during IABP 1:2 test, the change in IntR during IABP 1:2 test could help to predict the optimal time of weaning.

Outcome and complications of prolonged intraaortic balloon counterpulsation in cardiac patients

The risks and benefits of prolonged intraaortic balloon support for the management of refractory congestive heart failure and ischemia were studied in patients with end-stage heart disease who needed support for greater than or equal to 5 days. Fifty-two insertions were performed by the percutaneous femoral route in 49 patients. The duration of insertion ranged from 5 to 46 days (mean 11.3). Clinical outcome including hemodynamic parameters and complications were recorded. Mean systemic arterial pressure did not change with balloon insertion (74 +/- 19 vs 76 +/- 11 mm Hg; p = not significant). Both the mean pulmonary artery and pulmonary arterial wedge pressures decreased (33 +/- 8 to 26 +/- 9 mm Hg [p less than 0.01], and 25 +/- 8 to 17 +/- 6 mm Hg [p less than 0.01], respectively). Over time, both parameters tended to increase, but remained significantly less than those before insertion. Cardiac index increased from 1.6 +/- 0.4 to 2.2 +/- 0.5 liters/min/m2 on insertion and continued to increase to 2.7 +/- 0.5 liters/min/m2 (p less than 0.01) before removal. Definite balloon catheter infection developed in 7 patients, and hemorrhage occurred in an additional 7. Eleven patients had vascular compromise, with loss of pulse in 6, thrombosis of the femoral artery in 1, and pseudoaneurysm in 2. Lacerated femoral artery occurred in 1 patient, and mesenteric artery thrombosis in another. Twenty patients died from progressive heart failure and multiorgan system failure, and 19 survived to receive left ventricular assist device and heart transplantation. Only 10 patients were weaned off the balloon. In conclusion, prolonged intraaortic balloon pump support may be successfully used in end-stage heart disease.

The combined use of diastolic counterpulsation and coronary dilation in unstable angina due to multivessel disease under unstable hemodynamic conditions

Sixteen patients with multivessel ischemic heart disease and severely jeopardized myocardium required intra-aortic balloon counterpulsation subsequent to a deterioration in hemodynamics during or following a coronary angioplasty procedure. They had all suffered unstable angina which was refractory to intensive medical therapy, consisting of a combination of nitroglycerin, beta-adrenergic antagonists, and calcium blockers. Thirty angioplasties had been attempted (1.9 artery stem/patient) with a primary success rate of 90%. The symptoms of prolonged myocardial ischemia had disappeared, and the patient's blood pressure had normalized. No complications were associated with the use of the mechanical circulatory assistance. There were no deaths related to the procedure itself, and no myocardial infarctions. Emergency surgery was not required. One patient did die in hospital, however, due to cerebrovascular accident which occurred 4 days after removal of the mechanical circulatory support. Two also died suddenly later. One patient also required later elective coronary arterial bypass surgery and another needed repeated coronary dilation. The 12 remaining patients are asymptomatic at a follow-up with mean value of 22 months. Temporary intra-aortic diastolic counterpulsation is a useful adjunct to coronary angioplasty in patients with multivessel unstable angina and compromised hemodynamics.

Cardiogenic shock

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