Surviving critical COVID-19 requiring mechanical ventilation is associated with a high risk of cardiovascular events post discharge
Authors: Liliequist A , Nordberg P , Stahlberg M , Hofmann R , Svensson P 
Published: November 2023

Abstract

Background
The long-term risk for cardiovascular adverse events after severe COVID-19 requiring intensive care are largely unknown.

Purpose
The primary aim of this study was to investigate the composite risk of incident atherosclerotic cardiovascular disease (ASCVD) during six months after discharge from an intensive care unit (ICU) for severe COVID-19 requiring mechanical ventilation. Secondary aims were to assess the risk for individual cardiovascular and thrombotic events.

Methods
We performed a nationwide case-control study on all patients with severe COVID-19 treated with mechanical ventilation and discharged alive from an intensive care unit in Sweden between March 2020 and June 2021. Each case was matched (age, sex, district of residence) with up to 10 population-based controls. The study database was merged with multiple national registries. Patients with pre-existing diagnosis for MI longer than one month ago, CVL or Heart failure were excluded. Also COVID-19 patients receiving the same diagnosis during their ICU-stay as in the follow up period were excluded, making sure all post-covid events were new.
The primary outcome was a composite of ASCVD defined as a fatal or non-fatal myocardial infarction, unstable angina pectoris requiring urgent revascularization, fatal and non-fatal ischemic stroke and cardiovascular death. Secondary outcomes were pre-specified as, fatal or nonfatal MI, fatal or nonfatal stroke, myocarditis, pericarditis, PE and DVT. To compare groups, Hazard ratios (HR) with (95% CI) were calculated with adjustments for age, sex, comorbidities (hypertension, hyperlipedemia, diabetes 1&2, obesity, chronic kidney failure, atrial fibrillation, COPD, asthma, malignancy), level of education, marital status, and income quintile.

Results
In total, included 3 023 patients with severe Covid-19 that were treated with mechanical ventilation at a Swedish ICU and were subsequently discharged alive and compared with 28,463 control subjects. All results in Table 1.
The incidence rate for ASCVD was 22.2 (14.9-33.2) per 1,000 person years in patients discharged after severe COVID-19 compared to 2.9 (2.3-3.8) in control subjects. When adjusted for confounders, the risk for ASCVD during the follow-up period was increased compared to control subjects (HR 4.0, 95% CI 2.4-6.7).
The incidence rate for pulmonary embolism was 97.4 (80.6-120.0) per 1,000 person years after severe COVID-19 compared to 1.0 (0.6-1.7) in control subjects with a markedly increased risk HR 89.8 (95% CI 48.6-166.1) in patients discharged after severe Covid-19 compared to controls.

Conclusions
Among patients treated at the intensive care due to severe Covid-19, we found a significant and substantial increased risks for ASCVD and thrombotic events within 6 months from discharge. This finding implies that these patients should be closely monitored after discharge with a low threshold to initiate preventive treatment for ASCVD and thrombotic events during this period.