Myocardial Infarction across COVID-19 Pandemic Phases: Insights from the Veterans Health Affairs System

Abstract

AbstractBackgroundCardiovascular procedural treatments were deferred at scale during the COVID-19 pandemic, with unclear impact on patients presenting with Non-ST Elevation Myocardial Infarction (NSTEMI).MethodsIn a retrospective cohort study of all patients diagnosed with NSTEMI in the U.S. Veterans Affairs Healthcare System from 1/1/19 to 10/30/22 (n=67,125), procedural treatments and outcomes were compared between the pre-pandemic period and six unique pandemic phases (1: Acute phase, 2: Community spread, 3: First Peak, 4: Post-Vaccine, 5. Second Peak, 6. Recovery). Multivariable regression analysis was performed to assess association between pandemic phases and 30-day mortality.ResultsNSTEMI volumes dropped significantly with the pandemic onset (62.7% of pre-pandemic peak) and did not revert to pre-pandemic levels in subsequent phases, even after vaccine availability. Percutaneous coronary intervention (PCI) and/or coronary artery bypass grafting (CABG) volumes declined proportionally. Compared to the pre-pandemic period, NSTEMI patients experienced higher 30-day mortality during Phase 2 and 3, even after adjustment for COVID-19 positive status, demographics, baseline comorbidities, and receipt of procedural treatment (adjusted OR for Phase 2-3 combined: 1.26 [95% CI 1.13-1.43], p<0.01). Patients receiving VA-paid community care had a higher adjusted risk of 30-day mortality compared to those at VA hospitals across all six pandemic phases.ConclusionsHigher mortality after NSTEMI occurred during the initial spread and first peak of the pandemic, but resolved before the second, higher peak – suggesting effective adaptation of care delivery but a costly delay to implementation. Investigation into the vulnerabilities of the early pandemic spread are vital to informing future resource-constrained practices.Clinical PerspectiveWhat is New?After the initial significant decline in NSTEMI presentations during the acute phase of the pandemic, volumes of NSTEMI presentations and procedural treatment have not reverted to pre-pandemic levels despite widespread availability of vaccines in the Veterans Health Administration.Compared to the pre-pandemic period, 30-day mortality after NSTEMI increased during the initial spread and first pandemic peak (Phases 2 and 3) -- but resolved before the subsequent highest pandemic peak of Phase 5 -- suggesting a delay to implementation of adapted systems of cardiovascular care.The increased mortality was not significantly mediated by the decline in procedural volumes, suggesting appropriate triage of procedural care during the pandemic.What are the Clinical Implications?The COVID-19 pandemic appears to have had a lasting impact on health-seeking behaviors among NSTEMI patients, with unclear long-term effects of this increased threshold to obtain cardiovascular care.Investigation into the vulnerabilities that occurred during initial phases of the pandemic are urgently needed to inform ongoing and future resource-constrained practices.