Thrombolysis plus aortic counterpulsation: improved survival in patients who present to community hospitals with cardiogenic shock

Safety and utility of mechanical circulatory support in patients with acute myocardial infarction complicated by cardiogenic shock: A systematic review and meta-analysis

BACKGROUND

Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) is a major cause of morbidity and mortality. Although mechanical circulatory support (MCS) is an increasingly utilized therapeutic option in AMI-CS, studies evaluating the efficacy and safety of different forms of MCS have yielded conflicting results. This systematic review and meta-analysis aims to evaluate the safety and efficacy of different forms of MCS.

METHODS

A database search was performed for studies reporting on the association of different forms of MCS with clinical outcomes in patients with AMI-CS. The primary efficacy endpoints were short term (≤30 days) and long term (>30 days) all-cause mortality. Secondary efficacy endpoints included recurrent AMI, cardiovascular (CV) mortality, device-related limb complications, moderate to severe bleeding events, and cerebrovascular accidents (CVA).

RESULTS

2752 patients with AMI-CS met inclusion criteria. Results were available comparing ECMO to other MCS or medical therapy alone, comparing IABP to medical therapy alone, and comparing pLVAD to IABP. Use of ECMO was not associated with lower risk of 30-day or long-term mortality compared to pVAD or standard medical therapy with or without IABP placement but was associated with higher risk of device-related limb complications and moderate to severe bleeding compared to pVAD. IABP use was not associated with a lower risk of 30 day or long-term mortality but was associated with higher risk of recurrent AMI and moderate to severe bleeding compared to medical therapy. Compared to IABP, pVAD use was associated with lower risk of CV mortality but not recurrent AMI. pVAD was associated with a higher risk of device-related limb complications and moderate to severe bleeding compared to IABP use.

CONCLUSION

Use of ECMO or IABP in patients with AMI-CS is not associated with significant improvement in mortality. pVAD is associated with a lower risk of CV mortality. All MCS types are associated with increased risk of complications. Additional high-quality studies are needed to determine the optimal MCS therapy for patients with AMI-CS.

Perspectives and Considerations of IABP in the Era of ECMO for Cardiogenic Shock

The development of mechanical circulatory support (MCS) has been rapid, and its use worldwide in patients with cardiogenic shock is increasingly widespread. However, current statistical data and clinical research do not demonstrate its significant improvement in the patient prognosis. This review focuses on the widely used intra-aortic balloon pumps (IABP) and veno-arterial extracorporeal membrane oxygenation (VA-ECMO), analyzing and comparing their characteristics, efficacy, risk of complications, and the current exploration status of left ventricular mechanical unloading. Subsequently, we propose a rational approach to viewing the negative outcomes of current MCS, and look ahead to the future development trends of IABP.

Mechanical Circulatory Support in Acute Myocardial Infarction and Cardiogenic Shock

Mechanical circulatory support devices are increasingly used for the treatment of acute myocardial infarction complicated by cardiogenic shock. These devices provide different levels of univentricular and biventricular support, have different mechanisms of actions, and provide different physiologic effects. Institutions require expert teams to safely implant and manage these devices. This article reviews the mechanism of action, physiologic effects, and data as they relate to the utilization of these devices.

The Preference, Effect, and Prognosis of Intra-Aortic Balloon Counterpulsation in Acute Myocardial Infarction Complicated by Cardiogenic Shock Patients: A Retrospective Cohort Study

BACKGROUNDS

Intra-aortic balloon counterpulsation is increasingly used in acute myocardial infarction complicated by cardiogenic shock. The aim of this study was to explore the preference, effect, and prognosis of intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock patients.

METHODS

Data of acute myocardial infarction complicated by cardiogenic shock patients at the Fourth Medical Center of PLA General Hospital were collected retrospectively. A propensity score was calculated with a logistic regression which contained clinically meaningful variables and variables selected by Lasso and then used to match the control group. The cumulative incidence curve and Gray's test were employed to analyse the effect and prognosis of intra-aortic balloon counterpulsation on mortality.

RESULTS

A total of 1962 acute myocardial infarction cases admitted between May 2015 and November 2018 were identified, and 223 cases with acute myocardial infarction complicated by cardiogenic shock were included as the study cohort, which contained 34 cases that received IABP and 189 cases that did not receive IABP. Patients with higher alanine aminotransferase (OR = 1.93, 95% CI 1.29-2.98), higher triglyceride (OR = 3.71, 95% CI 1.87-7.95), and higher blood glucose (OR = 1.08, 95% CI 0.99-1.18) had a higher probability of receiving intra-aortic balloon counterpulsation. In the propensity score matching analysis, 34 cases received intra-aortic balloon counterpulsation and 102 matched controls were included in the comparison. By comparing the cumulative incidence of in-hospital mortality, there was no statistically significant difference between the intra-aortic balloon counterpulsation group and matched control group (P = 0.454).

CONCLUSION

The use of intra-aortic balloon counterpulsation may not improve the prognosis of the acute myocardial infarction complicated by cardiogenic shock patients.

Currently Available Options for Mechanical Circulatory Support for the Management of Cardiogenic Shock

Cardiogenic shock (CS) is a complex condition with a high risk for morbidity and mortality. Mechanical circulatory support (MCS) devices were developed to support patients with CS in cases refractory to treatment with vasoactive medications. Current devices include intra-aortic balloon pumps, intravascular microaxial pumps, percutaneous LVAD, percutaneous RVAD, and VA ECMO. Data from limited observational studies and clinical trials show a clear difference in the level of hemodynamic support offered by each device. However, at this point, there are insufficient clinical trial data to guide MCS selection and, until ongoing clinical trials are completed, use of the right device for the right patient depends largely on clinical judgment.

Complications of Temporary Percutaneous Mechanical Circulatory Support for Cardiogenic Shock: An Appraisal of Contemporary Literature

Cardiogenic shock (CS) is associated with hemodynamic compromise and end-organ hypoperfusion due to a primary cardiac etiology. In addition to vasoactive medications, percutaneous mechanical circulatory support (MCS) devices offer the ability to support the hemodynamics and prevent acute organ failure. Despite the wide array of available MCS devices for CS, there are limited data on the complications from these devices. In this review, we seek to summarize the complications of MCS devices in the contemporary era. Using a systems-based approach, this review covers domains of hematological, neurological, vascular, infectious, mechanical, and miscellaneous complications. These data are intended to provide a balanced narrative and aid in risk-benefit decision-making in this acutely ill population.

Percutaneous Mechanical Circulatory Support Devices in Cardiogenic Shock

Despite a high rate of early revascularization and use of intra-aortic balloon pump counterpulsation therapy, the prognosis of patients with cardiogenic shock has remained poor. In the hopes of improving outcomes, clinicians are increasingly turning to percutaneous left and right mechanical circulatory support devices. Until recently, the evidence base for these devices had consisted only of observational data, meta-analyses, and small feasibility trials. In this article, we describe the contemporary outcomes of patients with cardiogenic shock, the hemodynamics of cardiogenic shock, and hemodynamic effects of percutaneous mechanical circulatory support devices. We then use this discussion to provide clinicians with a useful framework for understanding when selecting between or while managing patients with a percutaneous mechanical circulatory support devices. We critically review the recently published data for and against the use of commercially available devices-the intra-aortic balloon pump counterpulsation, the Impella system, the TandemHeart, and venous-arterial extracorporeal membrane oxygenation-and highlight gaps in our understanding. Given such gaps, a consensus multidisciplinary approach that combines expertise from interventional cardiologists, heart failure specialists, cardiac surgeons, and cardiac anesthesiologists may help pair the right patient with the right device at the right time.

Effects of Additional Intra-aortic Balloon Counter-Pulsation Therapy to Cardiogenic Shock Patients Supported by Extra-corporeal Membranous Oxygenation

Extra-corporeal membranous oxygenation (ECMO) has been applied in patients with cardiopulmonary failure. One critical drawback of peripheral ECMO is an increase in left ventricular (LV) afterload which could be counterbalanced by the combination of intra-aortic balloon counter-pulsation (IABP) therapy. We hypothesized that an add-on therapy with IABP could improve outcomes in patients receiving ECMO support. We included patients (>18 years old) from 2002 to 2013 requiring ECMO support due to cardiogenic shock in a medical center. A total of 529 patients (227 ECMO alone and 302 combined IABP plus ECMO) were included. The mortality rates at 2 weeks (48.5 vs. 47.7%) after ECMO implantation were not different between the two groups (ECMO vs. combined group). After adjustment for propensity score and potential confounders, the odds ratios of outcomes within 14 days (combined group vs. ECMO) for poor LV systolic function, high preload, multi-organ failure and mortality were not different. The results remained similar for subgroup analysis. Compared with ECMO alone, combined IABP and ECMO treatment did not improve outcomes in patients with circulatory failure.

The outcomes of intra-aortic balloon pump usage in patients with acute myocardial infarction: a comprehensive meta-analysis of 33 clinical trials and 18,889 patients

BACKGROUND

The effects of intra-aortic balloon pump (IABP) usage in patients with acute myocardial infarction remain controversial. This study sought to evaluate the outcomes of IABP usage in these patients.

METHODS

Medline, EMBASE, and other internet sources were searched for relevant clinical trials. The primary efficacy endpoints (in-hospital, midterm, and long-term mortality) and secondary endpoints (reinfarction, recurrent ischemia, and new heart failure in the hospital) as well as safety endpoints (severe bleeding requiring blood transfusion and stroke in-hospital) were subsequently analyzed.

RESULTS

Thirty-three clinical trials involving 18,889 patients were identified. The risk of long-term mortality in patients suffering from acute myocardial infarction was significantly decreased following IABP use (odds ratio [OR] 0.66, 95% confidence interval [CI]: 0.48-0.91, P=0.010). Both in-hospital and midterm mortality did not differ significantly between the IABP use group and no IABP use group (in-hospital: OR 0.87, 95% CI: 0.59-1.28, P=0.479; midterm: OR 1.12, 95% CI: 0.53-2.38, P=0.768). IABP insertion was not associated with the risk reduction of reinfarction, recurrent ischemia, or new heart failure. However, IABP use increased the risk of severe bleeding requiring blood transfusion (OR 2.05, 95% CI: 1.29-3.25, P=0.002) and stroke (OR 1.71, 95% CI: 1.04-2.82, P=0.035). In the thrombolytic therapy and cardiogenic shock subgroups, reduced mortality rates following IABP use were observed.

CONCLUSION

IABP insertion is associated with feasible benefits with respect to long-term survival rates in patients suffering from acute myocardial infarction, particularly those suffering from cardiogenic shock and receiving thrombolytic therapy, but at the cost of higher incidence of severe bleeding and stroke.

Intra-aortic Balloon Pump Therapy for Acute Myocardial Infarction: A Meta-analysis

IMPORTANCE

Intra-aortic balloon pump (IABP) therapy is a widely used intervention for acute myocardial infarction with cardiogenic shock. Guidelines, which previously strongly recommended it, have recently undergone substantial change.

OBJECTIVE

To assess IABP efficacy in acute myocardial infarction.

DATA SOURCES

Human studies found in Pubmed, Embase, and Cochrane libraries through December 2014 and in reference lists of selected articles. Search strings were "myocardial infarction" or "acute coronary syndrome" and "intra-aortic balloon pump" or "counterpulsation."

STUDY SELECTION

Randomized clinical trials (RCTs) and observational studies comparing use of IABP with no IABP in patients with acute myocardial infarction.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted the data, and risk of bias in RCTs was assessed using the Cochrane risk of bias tool. We conducted separate meta-analyses of the RCTs and observational studies. Data were quantitatively synthesized using random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Thirty-day mortality.

RESULTS

There were 12 eligible RCTs randomizing 2123 patients. In the RCTs, IABP use had no statistically significant effect on mortality (odds ratio [OR], 0.96 [95% CI, 0.74-1.24]), with no significant heterogeneity among trials (I2 = 0%; P = .52). This result was consistent when studies were stratified by the presence (OR, 0.94 [95% CI, 0.69-1.28]; P = .69, I2 = 0%) or absence (OR, 0.98 [95% CI, 0.57-1.69]; P = .95, I2 = 17%) of cardiogenic shock. There were 15 eligible observational studies totaling 15 530 patients. Their results were mutually conflicting (heterogeneity I2 = 97%; P < .001), causing wide uncertainty in the summary estimate for the association with mortality (OR, 0.96 [95% CI, 0.54-1.70]). A simple index of baseline risk marker imbalance in the observational studies appeared to explain much of the heterogeneity in the observational data (R2meta = 46.2%; P < .001).

CONCLUSIONS AND RELEVANCE

Use of IABP was not found to improve mortality among patients with acute myocardial infarction in the RCTs, regardless of whether patients had cardiogenic shock. The observational studies showed a variety of mutually contradictory associations between IABP therapy and mortality, much of which was explained by the differences between studies in the balance of risk factors between IABP and non-IABP groups.

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.

Complications of Intra-Aortic Balloon Pump Use: Does the Final Position of the IABP Tip Matter?

We report results of a retrospective review of intra-aortic balloon pump (IABP) use in two Australasian centres and evaluate the effect of final IABP tip position on outcome. Indications for counterpulsation, patient demographics and in-hospital outcomes and complications were retrospectively collected. The chest X-ray reports provided the ‘final’ position of the IABP tip. The position was defined as acceptable (tip was seen just below the aortic arch, at T2–T5 vertebrae), malpositioned (tip >5 cm below aortic arch or at T5–T6) or severely malpositioned (tip >10 cm below aortic arch or at T7 or below). Major complications were considered a composite of death secondary to IABP, major limb ischaemia, major IABP malfunction, balloon rupture or haemorrhage, severe renal dysfunction (rise in creatinine >200 μmol/l), stroke and mesenteric ischaemia. Six hundred and forty-five cases were reviewed. The overall major complication rate was 26.2% and 24.3%. Severe renal impairment was the most common complication (16.6%), and second, severe catheter dysfunction (5.4%). Final IABP position was acceptable in 39.9%, malpositioned in 11.1%, severely malpositioned in 6.7% and unavailable for 42.4%. Logistic regression analysis showed IABP tip malposition (compared with satisfactory position odds ratio=3.9 [95% confidence interval=2.0–7.6, P <0.001] and severely malpositioned odds ratio=13.0 [95% confidence interval=5.3–31.7, P <0.001]) were associated with major complications more than the presence of shock (odds ratio=3.8, confidence interval 2.1–6.8 P <0.001). The acceptance of a less than ideal final position was highly predictive of morbidity directly related to IABP device therapy.

Current and future applications of the intra-aortic balloon pump

PURPOSE OF REVIEW

The intra-aortic balloon pump (IABP) has been used for more than 40 years. Although recommended in a wide variety of clinical settings, most of these indications are not evidence-based. This review focuses on studies challenging these traditional indications and evaluates potentially new applications of intra-aortic counterpulsation.

RECENT FINDINGS

Recent studies have failed to confirm an improvement in clinical outcomes conferred by the IABP in patients developing cardiogenic shock after acute myocardial infarction. This issue is in need of further investigations. While conflicting results of several retrospective studies and meta-analyses have been published regarding the performance of the IABP in high-risk percutaneous coronary interventions, it has recently been found to improve the long-term clinical outcomes of patients in whom it was implanted before the procedure. Small, single-center studies have reported the use of the IABP as a bridge to transplantation or candidacy for left-ventricular assist device implantation. The recently reported feasibility and safety of its insertion via the subclavian or axillary arteries will facilitate these applications.

SUMMARY

The revisiting of available data and the performance of new, thoughtfully designed trials should clarify the proper indications for the IABP.

Mechanical circulatory support in acute cardiogenic shock

Cardiogenic shock complicates about 5% to 8% of all admissions for acute myocardial infarction, and despite advancement in treatment over the past 50 years, mortality remains unacceptably high. Management with vasoactive agents after revascularization can have its limitations and thus mechanical circulatory support is often initiated. Intra-aortic balloon pumps (IABPs) are the devices most commonly used worldwide. IABPs appeared to improve mortality when used along with fibrinolytic therapy but may not when used along with percutaneous coronary interventions. Extracorporeal membrane oxygenation (ECMO) is utilized in the setting of worsening tissue perfusion despite inotropes and IABP utilization. Although retrospective studies show some mortality benefit, randomized prospective studies have not yet demonstrated ECMO to be advantageous either with or without IABP. Percutaneous left ventricular assist devices such as TandemHeart® and Impella are easier to institute than ECMO and are better for hemodynamics compared with the IABP but also have not yet shown a mortality benefit. More randomized studies are needed to define the most appropriate role of the various mechanical support devices in cardiogenic shock.

Counterpulsation: a concept with a remarkable past, an established present and a challenging future

The intra-aortic balloon pump (IABP), which is the main representative of the counterpulsation technique, has been an invaluable tool in cardiologists' and cardiac surgeons' armamentarium for approximately half a century. The IABP confers a wide variety of vaguely understood effects on cardiac physiology and mechano-energetics. Although, the recommendations for its use are multiple, most are not substantially evidence-based. Indicatively, the results of recently performed prospective studies have put IABP's utility in the setting of post-infarction cardiogenic shock into question. However, the particular issue remains open to further research. IABP support in high-risk patients undergoing PCI is associated with favorable long-term clinical outcome. In cardiac surgery, the use of IABP in cases of peri-operative low-output syndrome, refractory angina or ischemia-related mechanical complications is a usual, but poorly justified strategy. Anecdotal cases of treatment of incessant ventricular arrhythmias, reversal of right ventricular dysfunction and partial myocardial recovery have also been reported with its use. Converging data demonstrate the potential of safe long-term IABP support as a bridge to decision making or a bridge to transplantation modality in patients with heart failure. The feasibility of IABP insertion via other than the femoral artery sites enhances this potential. Despite the fact that several other counterpulsation devices have been developed and tested overtime none has managed to substitute the IABP, which continues to be most frequently used mechanical assist device.

The outcome of intra-aortic balloon pump support in acute myocardial infarction complicated by cardiogenic shock according to the type of revascularization: a comprehensive meta-analysis

AIMS

Despite the recommendations of the current guidelines, scientific evidence continue to challenge the effectiveness of intra-aortic balloon pump (IABP) in acute myocardial infarction (AMI) complicated by cardiogenic shock. Moreover, 2 recent meta-analyses showed contrasting results. The aim of this study is to test the effect of IABP according to the type of therapeutic treatment of AMI: percutaneous coronary intervention (PCI), thrombolytic therapy (TT), or medical therapy without reperfusion. Articles published from January 1, 1986, to December 31, 2012, were collected and analyzed by meta-analysis.

METHODS AND RESULTS

We evaluated the IABP impact on inhospital mortality, on safety end points (stroke, severe bleeding) and long-term survival, using risk ratio (RR) and risk difference (RD) estimates. We found that the risk of death was (i) not significantly different between the IABP and control groups (RR 0.95, P = .52; RD -0.04, P = .28), (ii) significantly reduced in the TT subgroup (RR 0.77, P < .0001; RD -0.16, P < .0001), and (iii) significantly increased in the PCI subgroup (RR 1.18, P = .01; RD 0.07, P = .01). There were no significant differences in secondary end points (P, not significant). In addition, we compared the meta-analyses collected over the same search period.

CONCLUSION

The results show that IABP support is significantly effective in TT reperfusion but is associated with a significant increase of the inhospital mortality with primary PCI. The comparison of the meta-analyses demonstrates the key role of analysing primary clinical treatments to avoid systematic errors.

[Ischaemic cardiogenic shock. Where do we stand in 2012?]

With a stable frequency (about 5% of acute coronary syndromes) and a mortality of nearly 45%, cardiogenic shock (CS), especially when it occurs in the immediate waning of myocardial infarction, still represents a therapeutic challenge. In this review, will be detailed the actual epidemiologic data of CS, its physiopathology and the different modalities of treatments available to the interventional cardiologist, especially the coronary revascularisation and the percutaneous left ventricular assistance, whether by intra-aortic balloon counterpulsation or by more complex systems.

What is the evidence for IABP in STEMI with and without cardiogenic shock?

Intraaortic balloon pump (IABP) is the most widely used left ventricular support device in a variety of indications. This review focuses on the current literature and discusses the evidence of IABP in ST-elevation myocardial infarction (STEMI) with and without cardiogenic shock. In high-risk STEMI patients without cardiogenic shock several randomized clinical trials have been performed. The majority of the studies could not demonstrate an efficacy benefit for IABP as adjunctive therapy in comparison to standard treatment alone. Hence, recent meta-analyses could not reveal diverging mortality rates at a higher incidence of stroke and major bleedings with IABP use independent of the type of reperfusion therapy. IABP in STEMI patients with cardiogenic shock is recommended according to current American College of Cardiology/American Heart Association (AHA/ACC) and European Society of Cardiology (ESC) guidelines. In recent meta-analyses, IABP in cardiogenic shock complicated by STEMI has been shown to be associated with decreased mortality. However, these beneficial effects are limited to patients treated with thrombolysis, whereas in patients undergoing mechanical revascularization IABP therapy is associated with an increase in mortality. Nevertheless, these data only arise from prospective and retrospective cohort studies, as up to date only one very small randomized clinical trial has been completed. In summary, in high-risk STEMI patients without cardiogenic shock, current data do not support the use of IABP and should only be considered as a standby and bailout strategy if patients develop haemodynamic instability. Current data on IABP in patients with cardiogenic shock complicated by STEMI are scarce and highly limited due to the nonrandomized design of previous trials. However, according to current AHA/ACC and ESC guidelines its use is recommended. Although recent meta-analyses challenge current AHA/ACC/ESC guidelines, adequately powered randomized studies are needed to elucidate the role of IABP in patients with acute myocardial infarction complicated by cardiogenic shock.

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.

Clinical review: mechanical circulatory support for cardiogenic shock complicating acute myocardial infarction

Acute myocardial infarction is one of the 10 leading reasons for admission to adult critical care units. In-hospital mortality for this condition has remained static in recent years, and this is related primarily to the development of cardiogenic shock. Recent advances in reperfusion therapies have had little impact on the mortality of cardiogenic shock. This may be attributable to the underutilization of life support technology that may assist or completely supplant the patient's own cardiac output until adequate myocardial recovery is established or long-term therapy can be initiated. Clinicians working in the intensive care environment are increasingly likely to be exposed to these technologies. The purpose of this review is to outline the various techniques of mechanical circulatory support and discuss the latest evidence for their use in cardiogenic shock complicating acute myocardial infarction.

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.

Comparison of hospital mortality with intra-aortic balloon counterpulsation insertion before versus after primary percutaneous coronary intervention for cardiogenic shock complicating acute myocardial infarction

Primary percutaneous coronary intervention (PCI) and intra-aortic balloon pump counterpulsation (IABP) are established treatment modalities in acute myocardial infarction complicated by cardiogenic shock. We hypothesized that the insertion of the IABP before primary PCI might result in better survival of patients with cardiogenic shock compared to postponing the insertion to after primary PCI. We, therefore, retrospectively studied 48 patients who had undergone primary PCI with IABP because of cardiogenic shock complicating acute myocardial infarction (26 patients received the IABP before and 22 patients after primary PCI). No significant differences were present in the baseline clinical characteristics between the 2 groups. The mean number of diseased vessels was greater in the group of patients treated with the IABP before primary PCI (2.8 +/- 0.5 vs 2.3 +/- 0.7, p = 0.012), but the difference in the number of treated vessels was not significant. The peak creatine kinase and creatine kinase -MB levels were lower in patients treated with the IABP before primary PCI (median 1,077, interquartile range 438 to 2067 vs median 3,299, interquartile range 695 to 6,834, p = 0.047, and median 95, interquartile range 34 to 196 vs median 192, interquartile range 82 to 467, p = 0.048, respectively). In-hospital mortality and the overall incidence of major adverse cardiac and cerebrovascular events were significantly lower in the group of patients receiving the IABP before primary PCI (19% vs 59% and 23% vs 77%, p = 0.007 and p = 0.0004, respectively). Multivariate analysis identified renal failure (odds ratio 15.2, 95% confidence interval 3.13 to 73.66) and insertion of the IABP after PCI (odds ratio 5.2, 95% confidence interval 1.09 to 24.76) as the only independent predictors of in-hospital mortality. In conclusion, the results of the present study suggest that patients with cardiogenic shock complicating acute myocardial infarction who undergo primary PCI assisted by IABP have a more favorable in-hospital outcome and lower in-hospital mortality than patients who receive IABP after PCI.

Percutaneous coronary intervention or coronary artery bypass surgery for cardiogenic shock and multivessel coronary artery disease?

BACKGROUND

Despite advances in treatment of cardiogenic shock (CS), the incidence of this serious complication of acute ST-elevation myocardial infarction (STEMI) has stayed relatively constant, and rates of mortality, although somewhat improved in recent decades, remain dauntingly high. Although both percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are used in patients with CS with multivessel coronary disease, the optimal revascularization strategy in this setting remains unknown.

METHODS

We conducted a literature search and review of English language publications on CS in multiple online medical databases. Studies were included if they were (1) randomized controlled trials or observational cohort studies, (2) single-center or multicenter reports, (3) prospective or retrospective studies, and (4) contained information on PCI and CABG. Non-English language studies were excluded.

RESULTS

Our search retrieved no published findings from randomized clinical trials, and only 4 observational reports evaluating PCI versus CABG. Our review of the limited available data suggests similar mortality rates with CABG and PCI in patients with STEMI and multivessel coronary disease complicated by CS.

CONCLUSIONS

Limited data from observational studies in patients with CS and multivessel disease suggest that CABG should be considered a complementary reperfusion strategy to PCI and may be preferred, especially when complete revascularization with PCI is not possible. Our data highlight the need for large randomized trials to further evaluate the relative benefit of PCI versus CABG in patients with multivessel coronary disease and CS using contemporary surgical and percutaneous techniques.

Experiencia inicial con la asistencia ventricular izquierda tipo «Impella» para el shock cardiogénico poscardiotomía y la angioplastia de tronco coronario izquierdo no protegido con baja fracción de eyección ventricular izquierda

Low-output syndrome is one of the leading causes of death following open-heart surgery or high-risk angioplasty. Ventricular assist devices have been used to treat patients who suffer from postoperative cardiogenic shock despite use of an intraaortic balloon pump and maximum inotropic support. The Impella pump (Impella Cardiosystems AG, Aachen, Germany) is a newly introduced left ventricular assist device that has been shown to reduce infarct size and to accelerate recovery of stunned myocardium. We report our initial experience using the Impella device for the treatment of cardiogenic shock following cardiopulmonary bypass and for maintaining hemodynamic stability in high-surgical-risk patients undergoing unprotected left coronary artery angioplasty.

Interhospital transfer for early revascularization in patients with ST-elevation myocardial infarction complicated by cardiogenic shock--a report from the SHould we revascularize Occluded Coronaries for cardiogenic shocK? (SHOCK) trial and registry

BACKGROUND

Early revascularization (ERV) in patients with ST-elevation myocardial infarction (STEMI) and cardiogenic shock (CS) reduces mortality rates. Patients admitted to hospitals without revascularization capability have high mortality rates and are not often transferred for ERV.

METHODS

Transfer and direct-admit patients with STEMI from the SHOCK Trial and Registry with left ventricular failure (N = 969) were analyzed to determine benefit of ERV in transfer patients.

RESULTS

Transfer patients (46%) were younger and less likely to have prior hypertension, myocardial infarction, and heart failure. They received more aggressive treatment, were revascularized later after CS (median 7.3 vs 3.9 hours, P = .0002), and had similar adjusted inhospital mortality compared with direct-admit patients (55% vs 56%). Inhospital mortality was lower in ERV than no/late revascularization (41% vs 53%, P = .017 for transfer patients; 55% vs 71%, P = .0003 for direct-admit patients). Multiple logistic regression showed that inhospital mortality was associated with age (odds ratio [OR] 1.50 per decade increase, 95% CI 1.31-1.73, P < .0001), mean arterial pressure (OR 0.98 per 1 mm Hg increase, 95% CI 0.97-0.99, P < .0001), fibrinolysis before CS (OR 0.65, 95% CI 0.52-0.96, P = .040), and ERV (OR 0.70, 95% CI 0.52-0.96, P = .028), but not transfer admission (OR 1.23, 95% CI 0.86-1.74, P = .26).

CONCLUSIONS

Despite longer time to treatment, transfer patients are a selected population with similar adjusted inhospital mortality and ERV benefit as direct-admit patients. Selected patients with STEMI and CS admitted to hospitals without revascularization capability should be transferred to centers with revascularization capability for immediate angiography.

Management of Perioperative Myocardial Infarction in Noncardiac Surgical Patients

Perioperative myocardial infarction (PMI) is a major cause of morbidity and mortality in patients undergoing noncardiac surgery. The incidence of PMI varies depending on the method used for diagnosis and is likely to increase as the population ages. Studies have examined different methods for prevention of myocardial infarction (MI), including the use of perioperative beta-blockers, alpha(2)-agonists, and statin therapy. However, few studies have focused on the treatment of PMI. Current therapy for acute MI generally involves anticoagulation and antiplatelet therapy, raising the potential for surgical site hemorrhage in this population. This article reviews the possible mechanisms, diagnosis, and treatment options for MI in the surgical setting. We also suggest algorithms for treatment.

Therapeutic strategies for cardiogenic shock, 2006

Cardiogenic shock, a devastating consequence of acute myocardial infarction, is associated with extremely high mortality. Treatment strategies should focus on prompt reperfusion and hemodynamic support. The primary approach for therapy is emergent angiography and revascularization using percutaneous coronary intervention or coronary artery bypass surgery, with the assistance of intra-aortic balloon pump counterpulsation. Several adjunctive pharmacologic agents, particularly inotropic drugs and vasopressors, are also helpful for hemodynamic support. However, these agents have not been shown to provide a survival benefit, and their use is primarily based on clinical experience. Since our last publication, several important advances have been made in the understanding and treatment of cardiogenic shock. Recent evidence suggests that a systemic inflammatory response, including the upregulation of inducible nitric oxide synthase, complement activation, and an inflammatory cytokine cascade, play a role in the development of cardiogenic shock. Newer therapeutic strategies, including C5 inhibitors and nitric oxide synthase inhibitors, are being combined with traditional strategies, such as inotropic agents, vasopressors, and circulatory assist, to treat cardiogenic shock.

Management of cardiogenic shock attributable to acute myocardial infarction in the reperfusion era

Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction. It is defined as tissue hypoperfusion resulting from ventricular pump failure in the presence of adequate intravascular volume. Rapid assessment and triage of patients presenting in cardiogenic shock followed by appropriate institution of supportive therapies including vasopressor and inotropic agents, mechanical ventilatory support, and intra-aortic balloon pump counterpulsation are critical for effective management of these patients. However, emergency percutaneous coronary intervention or coronary artery bypass graft surgery is required to decrease mortality rates. Novel approaches, including inhibition of nitric oxide synthase and new mechanical support devices, may further decrease mortality rates, which remain high despite reperfusion therapy.

Thrombolysis and Counterpulsation to Improve Survival in Myocardial Infarction Complicated by Hypotension and Suspected Cardiogenic Shock or Heart Failure: Results of the TACTICS Trial

BACKGROUND

Sustained hypotension, cardiogenic shock, and heart failure all imply a poor prognosis in acute myocardial infarction (MI). We assessed the benefit of adding 48 hours of intra-aortic balloon counterpulsation (IABP) to standard treatment for MI, in an international trial among hospitals without primary angioplasty capabilities.

METHODS

We randomized 57 patients with MI complicated by sustained hypotension, possible cardiogenic shock, or possible heart failure to receive either fibrinolytic therapy and IABP or fibrinolysis alone. The primary end point was all-cause mortality at 6 months.

RESULTS

In all, IABP was inserted in 27 of 30 assigned patients a median 30 minutes after fibrinolysis began and continued for a median 34 hours. Of the 27 patients assigned to fibrinolysis alone, 9 deteriorated such that IABP was required. The IABP group was at slightly higher risk at baseline, but the incidence of the primary end point did not differ significantly between groups (34% for combined treatment versus 43% for fibrinolysis alone; adjusted P = 0.23). Patients with Killip class III or IV showed a trend toward greater benefit from IABP (6-month mortality 39% for combined therapy versus 80% for fibrinolysis alone; P = 0.05).

CONCLUSIONS

While early IABP use was not associated with a definitive survival benefit when added to fibrinolysis for patients with MI and hemodynamic compromise in this small trial, its use suggested a possible benefit for patients with the most severe heart failure or hypotension. ABBREVIATED ABSTRACT: We assessed the benefit of adding 48 hours of intra-aortic balloon counterpulsation to fibrinolytic therapy among 57 patients with acute myocardial infarction complicated by sustained hypotension, possible cardiogenic shock, or possible heart failure. The primary end point, mortality at 6 months, did not differ between groups (34% for combined treatment versus 43% for fibrinolysis alone [n = 27]; adjusted P = 0.23), although patients with Killip class III or IV did show a trend toward greater benefit from IABP (39% for combined therapy versus 80% for fibrinolysis; P = 0.05).

Therapeutic Strategies for Cardiogenic Shock

Cardiogenic shock is a devastating consequence of acute myocardial infarction; it is associated with an extremely high mortality. Treatment strategies should be focused on prompt reperfusion, as well as hemodynamic support. The optimal approach for therapy is emergent angiography and revascularization using percutaneous coronary intervention or coronary artery bypass surgery, with the assistance of intra-aortic balloon pump counterpulsation. Several adjunctive pharmacologic agents, particularly inotropic drugs and vasopressors, are also helpful for hemodynamic support. However, these agents have not been shown to provide a survival benefit, and their use is primarily based on clinical experience.

Effects of intraaortic balloon augmentation in a porcine model of endotoxemic shock

OBJECTIVE

Patients with septic shock commonly have myocardial dysfunction associated with lactic acid production and troponin I release. The purpose of this study was to evaluate the effects on intraaortic balloon pump (IABP) support on myocardial dysfunction.

DESIGN

Prospective, randomized controlled study.

SETTING

Animal research laboratory.

METHODS

Ten pigs had arterial, pulmonary arterial, and coronary catheters inserted. After receiving endotoxin infusion over 30 min, half the animals received IABP support.

RESULTS

Coronary sinus lactic acid levels (P< 0.05 for both 90 min versus baseline and 60 min versus baseline) and arterial lactic acid levels (P < 0.05 for both 90 min versus baseline and 60 min versus baseline) increased with time but did not differ between IABP and sham groups. While overall there was no difference with time in myocardial lactic acid consumption or production (calculated as arterial lactic acid level minus coronary sinus lactic acid level), the IABP group showed net myocardial lactic acid consumption at 90 min, while the sham group showed myocardial lactic acid production. Three of five animals in each group showed troponin I release. The levels were similar and did not differ between groups.

CONCLUSION

IABP had no benefits in this porcine model of endotoxemic shock.

Acute myocardial infarction: disposition to the operating room?

Given their low incidence, mechanical complications of AMI represent a diagnostic and therapeutic challenge for the EP. When the panoply of medical interventions has reached its limitation, surgical treatment plays a role in the management of the patient who has AMI. For patients who have CS and severe compromise of myocardial reserve, surgical intervention might represent the only means of restoring blood flow to the myocardium. For patients who have mechanical complications, correction of the defect before the onset of terminal organ failure might provide long-term survival.