Benefits of Intraaortic Balloon Support for Myocardial Infarction Patients in Severe Cardiogenic Shock Undergoing Coronary Revascularization

RESEARCH ARTICLE Benefits of Intraaortic Balloon Support for Myocardial Infarction Patients in Severe Cardiogenic Shock Undergoing Coronary Revascularization Chun-Tai Mao1☯, Jian-Liang Wang2☯, Dong-Yi Chen3, Ming-Lung Tsai3, Yu-Sheng Lin4, Wen-Jin Cherng1, Chao-Hung Wang1, Ming-Shien Wen3, I-Chang Hsieh3, Ming-Jui Hung1, Chun-Chi Chen3, Tien-Hsing Chen1* a11111 1 Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung, Taiwan, and Chang Gung University College of Medicine, Taoyuan, Taiwan, 2 Division of Cardiology, Landseed Hospital, Pingzhen City, Taiwan, 3 Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan, 4 Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan, and Chang Gung University College of Medicine, Taoyuan, Taiwan ☯ These authors contributed equally to this work. * OPEN ACCESS Citation: Mao C-T, Wang J-L, Chen D-Y, Tsai M-L, Lin Y-S, Cherng W-J, et al. (2016) Benefits of Intraaortic Balloon Support for Myocardial Infarction Patients in Severe Cardiogenic Shock Undergoing Coronary Revascularization. PLoS ONE 11(8): e0160070. doi:10.1371/journal.pone.0160070 Editor: Katriina Aalto-Setala, University of Tampere, FINLAND Received: April 5, 2016 Abstract Background Prior studies have suggested intraaortic balloon pump (IABP) have a neutral effect on acute myocardial infarction (AMI) patients with cardiogenic shock (CS). However, the effects of IABP on patients with severe CS remain unclear. We therefore investigated the benefits of IABP in AMI patients with severe CS undergoing coronary revascularization. Accepted: July 13, 2016 Published: August 2, 2016 Copyright: © 2016 Mao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The data of our cohort were retrieved from the National Health Insurance Research Database (NHIRD) in Taiwan. NHIRD are available via http://nhird.nhri.org.tw/en/index.htm. Funding: The authors have no support or funding to report. Competing Interests: The authors have declared that no competing interests exist. Methods and Results This study identified 14,088 adult patients with AMI and severe CS undergoing coronary revascularization from Taiwan’s National Health Insurance Research Database between January 1, 1997 and December 31, 2011, dividing them into the IABP group (n = 7044) and the Nonusers group (n = 7044) after propensity score matching to equalize confounding variables. The primary outcomes included myocardial infarction(MI), cerebrovascular accidents or cardiovascular death. In-hospital events including dialysis, stroke, pneumonia and sepsis were secondary outcomes. Primary outcomes were worse in the IABP group than in the Nonusers group in 1 month (Hazard ratio (HR) = 1.97, 95% confidence interval (CI) = 1.84–2.12). The MI rate was higher in the IABP group (HR = 1.44, 95% CI = 1.16–1.79), and the cardiovascular death was much higher in the IABP group (HR = 2.07, 95% CI = 1.92– 2.23). The IABP users had lower incidence of dialysis (8.5% and 9.5%, P = 0.04), stroke (2.6% and 3.8%, P<0.001), pneumonia (13.9% and 16.5%, P<0.001) and sepsis (13.2% and 16%, P<0.001) during hospitalization than Nonusers. PLOS ONE | DOI:10.1371/journal.pone.0160070 August 2, 2016 1 / 14 Benefits of IABP in Severe Cardiogenic Shock Conclusion The use of IABP in patients with myocardial infarction and severe cardiogenic shock undergoing coronary revascularization did not improve the outcomes of recurrent myocardial infarction and cardiovascular death. However, it did reduce the incidence of dialysis, stroke, pneumonia and sepsis during hospitalization. Introduction Acute myocardial infarction (AMI) complicated with cardiogenic shock (CS) is a complex syndrome which may induce low cardiac output and hypotension followed by multi-organ dysfunction [1]. Its mortality rate is between 40% to 60% even after early revascularization, including percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) [2–4]. In order to stabilize these critically ill patients, mechanical assistive devices such as intraaortic balloon pump (IABP), percutaneous left ventricular assist devices (for example, Impella) or venoarterial extracorporeal membrane oxygenationators (ECMO) have been developed to support hemodynamics, in addition to inotropic agents [5–7]. One mechanical assist device, IABP, has been used since 1968 [8], and has become a mature technology; it is the most common method of mechanical cardiac assistance used in acute cardiology today [9]. According to previous studies, IABP can increase diastolic coronary and systemic blood flow, and it reduces afterload and myocardial work, which is supposed to protect LV function and avoid low cardiac output [10,11]. A large national registry study with 23,810 patients in the US revealed that using IABP in patients with CS and AMI undergoing thrombolysis reduced in-hospital mortality by 18% [12], and a meta-analysis of cohort studies revealed that using IABP decreased 30-day mortality by 18% in these patients [9]. However, systemic review of randomized control trials (RCTs) revealed IABP did not improve outcomes either for patients undergoing thrombolysis or early revascularization [5,9]. Furthermore, the CRISP-AMI trial suggested that prophylactic use of IABP in AMI patients without CS does not improve cardiovascular outcomes either [13]. The benefits of IABP have thus become controversial. Then the overall use of IABP decreased significantly from 0.99% in 1998 to 0.36% in 2008 in the US [14]. In an effort to confirm its effect, a large well-designed RCT, IABP-SHOCK II, was performed. Its results showed that IABP may have less or no benefit for patients with AMI complicated by CS compared to standard therapy with inotropic agents in the following 30 days and one year [15,16]. According to the supplementary appendix of IABP-SHOCK II, over 95% of patients in the IABP group received inotropic agents to stabilize their hemodynamics [15]. The median dose of dopamine, norepinephrine and dobutamine administered to both groups was 4 ug/kg per minute, 0.3 ug/kg per minute and 10 ug/kg per minute [15]. The relatively lower doses of inotropic agents used and the relative lower mortality rate in one month (approximately 40%, as compared with 42% to 48% in other RCTs and registries) may indicate that this trial included a higher percentage of patients with mild or moderate CS, a factor that might preclude generalizing the results to patients with severe CS [2–4]. In order to evaluate the effect of IABP in patients with severe CS who need higher dose of inotropic agents, we design this study. Methods Study (...truncated)