Myocardial infarction with non-obstructive coronary arteries as compared with myocardial infarction and obstructive coronary disease: outcomes in a Medicare population

Abstract

Aims: The prognosis of patients with MINOCA (myocardial infarction with non-obstructive coronary arteries) is poorly understood. We examined major adverse cardiac events (MACE) defined as all-cause mortality, re-hospitalization for acute myocardial infarction (AMI), heart failure (HF), or stroke 12-months post-AMI in patients with MINOCA versus AMI patients with obstructive coronary artery disease (MICAD).

Methods and results: Multicentre, observational cohort study of patients with AMI (≥65 years) from the National Cardiovascular Data Registry CathPCI Registry (July 2009-December 2013) who underwent coronary angiography with linkage to the Centers for Medicare and Medicaid (CMS) claims data. Patients were classified as MICAD or MINOCA by the presence or absence of an epicardial vessel with ≥50% stenosis. The primary endpoint was MACE at 12 months, and secondary endpoints included the components of MACE over 12 months. Among 286 780 AMI admissions (276 522 unique patients), 16 849 (5.9%) had MINOCA. The 12-month rates of MACE (18.7% vs. 27.6%), mortality (12.3% vs. 16.7%), and re-hospitalization for AMI (1.3% vs. 6.1%) and HF (5.9% vs. 9.3%) were significantly lower for MINOCA vs. MICAD patients (P < 0.001), but was similar between MINOCA and MICAD patients for re-hospitalization for stroke (1.6% vs. 1.4%, P = 0.128). Following risk-adjustment, MINOCA patients had a 43% lower risk of MACE over 12 months (hazard ratio = 0.57, 95% confidence interval 0.55-0.59), in comparison to MICAD patients. This pattern was similar for adjusted risks of the MACE components.

Conclusion: This study confirms an unfavourable prognosis in elderly patients with MINOCA undergoing coronary angiography, with one in five patients with MINOCA suffering a major adverse event over 12 months.

Keywords: AMI and obstructive coronary disease; Clinical outcomes; Myocardial infarction with non-obstructive coronary arteries; Prognosis.

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.

Figures

Figure 1

Study sample selection flow diagram. aMatching by patients through the National Cardiovascular Data Registry patient ID and Centers for Medicare and Medicaid beneficiary ID in the crosswalk data file. This crosswalk data file was created using the patients’ direct identifiers, while the administrative data was requested for all the patients in all the ACC registries. bMatching by patient beneficiary ID and the discharge date.

Figure 2

Kaplan–Meier curves for unadjusted incidence of outcomes over 12 months showing the cumulative incidence for (A) major adverse cardiac events, (B) mortality, (C) acute myocardial infarction re-hospitalization, (D) heart failure re-hospitalization, (E) stroke re-hospitalization, and (F) all-cause re-hospitalization (blue line: MICAD; red line: MINOCA).

Figure 3

A forest plot showing unadjusted/adjusted hazard ratio and 95% confidence interval for the independent effect of MINOCA on (A) 12-month major adverse cardiac events, mortality, and readmission; and (B) readmission for acute myocardial infarction, congestive heart failure, and stroke. Cox models, censored at 12 months; competing risk also considered here.

Take home figure

A forest plot showing unadjusted/adjusted hazard ratio and 95% confidence interval for the independent effect of MINOCA on 12-month outcomes. In the unadjusted model, MINOCA patients had a lower likelihood of major adverse cardiac events, mortality from discharge, and re-hospitalization vs. MICAD patients. After adjusting for confounders, MINOCA patients had a significant but persistently lower hazard of major adverse cardiac events, mortality following discharge, and a lower likelihood of re-hospitalization.