Myocardial Infarction among Veterans across COVID-19 Pandemic Phases
In 2020, the rapid spread of the novel coronavirus worldwide forced VA hospitals across the country to start triaging the delivery of medical procedures, in efforts to flatten the curve of COVID-19 growth and its associated high mortality. VA hospitals nationwide received mandates to postpone all elective cardiovascular procedures, while permitting only urgent, life-threatening ones. In tandem, federal mandates and professional medical societies published guidelines recommending similar deferrals of non-urgent cardiovascular procedures at hospitals nationwide.
There are important reasons why this novel approach – both triaging cardiovascular procedures and deferring those that are non-urgent – warrants rapid evaluation: (1) COVID-19 has produced an unprecedented, natural experiment to demonstrate the comparative effectiveness of a vast number of high cost procedures to guide future treatment decisions on usefulness of therapies or de-implementation; (2) evaluation of this approach will inform how to best manage healthcare rationing responses in disaster situations, pandemics, workforce disruptions, and abrupt changes in operational capacity or funding; and (3) we must determine whether vulnerable populations are disproportionately impacted by this approach to ensure that we are delivering equitable care to our Veterans at the highest risk of adverse health outcomes. The pandemic has created an opportunity to evaluate this approach, an evaluation that traditional randomized controlled trials will likely never accomplish.
As part of an HSR&D-funded COVID-19 Rapid Response project, we are examining how the new treatment paradigm during the pandemic has impacted Veterans presenting with myocardial infarction. We are focusing on procedural treatments for myocardial infarction given the strong evidence base for their potential to reduce mortality, particularly if delivered in a timely manner in the case of ST-Elevation MI (STEMI). We are comparing trends in myocardial infarction presentation, procedural treatments, and outcomes between the pre-pandemic phase and four unique pandemic phases, with sub-analysis across race, ethnicity, and sociodemographic factors. We are also performing mediation analysis to assess the impact of decreased procedures on 30-day mortality.
Using the VA Corporate Data Warehouse and the VA Cardiovascular Assessment Reporting and Tracking System for Cath Labs, we are using ICD-10 codes to identify patients requiring inpatient care for STEMI or non-STEMI (NSTEMI). We are including all patients diagnosed with STEMI or NSTEMI in the VA healthcare system from January 1, 2019 to August 15, 2021 (n=30,840). Veterans are being categorized into one of four pre-defined COVID phases according to the date of their first STEMI or Non-STEMI diagnosis during the study period, as described below.
Pre-Pandemic (January 1, 2019 through February 15, 2020). Defined as the one-year period prior to the pandemic.
Phase 1 (“Acute Phase,” February 16, 2020 through April 14, 2020). Defined as the two-month period surrounding the initial nadir of patient and procedural volumes due to the pandemic, which included the period of initial stay-at-home orders and VA directives to limit cardiovascular procedures to essential ones.
Phase 2 (“Recovery Phase,” April 15, 2020 through December 14, 2020). Defined as the initial recovery period during which VA hospitals started to phase back elective procedures but no vaccines were yet available to Veterans.
Phase 3 (“Vaccine Initiation Phase,” December 15, 2020 through May 31, 2021). Defined as the period during which Veterans started receiving the COVID-19 vaccine through VA.
Phase 4 (“Post-Vaccine Phase,” June 1, 2021 through August 15, 2021). Defined as the most recent recovery period after which all Veterans who desired vaccination should have had the opportunity to receive one, and cardiac catheterization labs had largely resumed routine practices.
We hope to better understand whether our methods of triage within VA were appropriately executed, and whether cardiovascular outcomes among Veterans changed during this evolving paradigm of care. Findings from this study will be important for informing the optimal triage of cardiovascular procedures under resource-constrained settings, including the ongoing pandemic, as well as how we routinely prioritize cardiovascular procedures moving forward.