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Hospital market concentration and the use of mechanical circulatory support devices in acute myocardial infarction complicated by cardiogenic shock.

ABSTRACT:

Background

As health care markets in the United States have become increasingly consolidated, the role of market concentration on physician treatment behavior remains unclear. In cardiology, specifically, there has been evolving treatment of acute myocardial infarction complicated by cardiogenic shock (AMI-CS) with increasing use of mechanical circulatory support (MCS). However, there remains wide variation in it use. The role of market concentration in the utilization of MCS in AMI-CS is unknown. We examined the use of MCS in AMI-CS and its effect on outcomes between competitive and concentrated markets.

Methods and results

We used the National Inpatient Sample to query patients admitted with AMI-CS between 2003 and 2009. The primary study outcome was the use of mechanical circulatory support. The primary study exposure was market concentration, measured using the Herfindahl-Hirschman Index, which was used to classify markets as unconcentrated (competitive), moderately concentrated, and highly concentrated. Baseline characteristics, procedures, and outcomes were compared for patients in differently concentrated markets. Multivariable logistic regression was used to examine the association between HHI and use of MCS.

Results

There were 32,406 hospitalizations for patients admitted with AMI-CS. Patients in unconcentrated markets were more likely to receive MCS than in highly concentrated markets (unconcentrated 46.8% [5087/10,873], moderately concentrated 44.9% [2933/6526], and high concentrated 44.5% [6676/15,007], p < 0.01). Multivariable regression showed that patients in more concentrated markets had decreased use of MCS in patients in later years of the study period (2009, OR 0.64, 95% CI 0.44-0.94, p = 0.02), with no effect in earlier years. There was no significant difference in in-hospital mortality.

Conclusion

Multivariable analysis did not show an association with market concentration and use of MCS in AMI-CS. However, subgroup analysis did show that competitive hospital markets were associated with more frequent use of MCS in AMI-CS as frequency of utilization increased over time. Further studies are needed to evaluate the effect of hospital market consolidation on the use of MCS and outcomes in AMI-CS.

SUBMITTER: Vohra AS

PROVIDER: S-EPMC8772168 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceMechanical circulatory support (MCS) devices, including intravascular microaxial left ventricular assist devices (LVADs) and intra-aortic balloon pumps (IABPs), are used in patients who undergo percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) complicated by cardiogenic shock despite limited evidence of their clinical benefit.ObjectiveTo examine trends in the use of MCS devices among patients who underwent PCI for AMI with cardiogenic shock, hospital-level use variation, and factors associated with use.Design, setting, and participantsThis cross-sectional study used the CathPCI and Chest Pain-MI Registries of the American College of Cardiology National Cardiovascular Data Registry. Patients who underwent PCI for AMI complicated by cardiogenic shock between October 1, 2015, and December 31, 2017, were identified from both registries. Data were analyzed from October 2018 to August 2020.ExposuresTherapies to provide hemodynamic support were categorized as intravascular microaxial LVAD, IABP, TandemHeart, extracorporeal membrane oxygenation, LVAD, other devices, combined IABP and intravascular microaxial LVAD, combined IABP and other device (defined as TandemHeart, extracorporeal membrane oxygenation, LVAD, or another MCS device), or medical therapy only.Main outcomes and measuresUse of MCS devices overall and specific MCS devices, including intravascular microaxial LVAD, at both patient and hospital levels and variables associated with use.ResultsAmong the 28 304 patients included in the study, the mean (SD) age was 65.4 (12.6) years and 18 968 were men (67.0%). The overall MCS device use was constant from the fourth quarter of 2015 to the fourth quarter of 2017, although use of intravascular microaxial LVADs significantly increased (from 4.1% to 9.8%; P < .001), whereas use of IABPs significantly decreased (from 34.8% to 30.0%; P < .001). A significant hospital-level variation in MCS device use was found. The median (interquartile range [IQR]) proportion of patients who received MCS devices was 42% (30%-54%), and the median proportion of patients who received intravascular microaxial LVADs was 1% (0%-10%). In multivariable analyses, cardiac arrest at first medical contact or during hospitalization (odds ratio [OR], 1.82; 95% CI, 1.58-2.09) and severe left main and/or proximal left anterior descending coronary artery stenosis (OR, 1.36; 95% CI, 1.20-1.54) were patient characteristics that were associated with higher odds of receiving intravascular microaxial LVADs only compared with IABPs only.Conclusions and relevanceThis study found that, among patients who underwent PCI for AMI complicated by cardiogenic shock, overall use of MCS devices was constant, and a 2.5-fold increase in intravascular microaxial LVAD use was found along with a corresponding decrease in IABP use and a significant hospital-level variation in MCS device use. These trends were observed despite limited clinical trial evidence of improved outcomes associated with device use.

Project description:OBJECTIVES:To review temporary percutaneous mechanical circulatory support devices for the treatment of cardiogenic shock, including current evidence, contraindications, complications, and future directions. DATA SOURCES:A MEDLINE search was conducted with MeSH terms: cardiogenic shock, percutaneous mechanical circulatory support, extracorporeal membrane oxygenation, Impella, and TandemHeart. STUDY SELECTION:Selected publications included randomized controlled trial data and observational studies describing experience with percutaneous mechanical circulatory support in cardiogenic shock. DATA EXTRACTION:Studies were chosen based on strength of association with and relevance to cardiogenic shock. DATA SYNTHESIS:Until recently, there were few options if cardiogenic shock was refractory to vasopressors or intra-aortic balloon pump counterpulsation. Now, several percutaneous mechanical circulatory support devices, including Impella (Abiomed, Danvers, MA), TandemHeart (CardiacAssist, Pittsburgh, PA), and extracorporeal membrane oxygenation, are more accessible. Compared with intra-aortic balloon pump, Impella provides greater hemodynamic support but no reduction in mortality. Similarly, TandemHeart improves hemodynamic variables but not survival. Comparative studies have been underpowered for mortality because of small sample size. Veno-arterial extracorporeal membrane oxygenation offers the advantage of biventricular circulatory support and oxygenation, but there are significant vascular complications. Comparative studies with extracorporeal membrane oxygenation have not been completed. Despite lack of randomized controlled data, there has been a substantial increase in use of percutaneous mechanical circulatory support. Several ongoing prospective studies with larger sample sizes may provide answers, and newer devices may become smaller, easier to insert, and more effective. CONCLUSIONS:Mortality from cardiogenic shock remains unacceptably high despite early coronary revascularization or other therapies. Although evidence is lacking and complications rates are high, improvements and experience with percutaneous mechanical circulatory support may offer the prospect of better outcomes.