Native T1 is independently predictive of aerobic functional capacity by VO2max in long-term follow-up of individuals with mild initial COVID disease (RF_TH_171)

Background: Cardiovascular inflammatory involvement is an increasingly recognized sequela of COVID-19 disease, acutely and chronically months and years after the resolution of the initial viral illness. Cardiac MRI studies recorded subtle myocardial inflammatory changes, non-ischemic myocardial scarring and pericarditis, also in previously well individuals with a mild initial course of disease. Native T1 and female sex were independent predictors of symptoms after approximately one year from infection. The longer-term outcomes of functional capacity and associations with imaging measures remain to be determined.

Methods: We report the preliminary results in a subcohort of individual from a prospective longitudinal outcome study.  All subjects were evaluated consecutively after a minimum of 3 years from the first documented COVID-19 infection. None of the patients had previously known or had evidence of structural heart disease in previous CMR assessments performed after a minimum of 4 weeks and 4 months). All subjects underwent standardised contrast-enhanced CMR scan at 3 Tesla (gadobutrol 0.1 mmol/kg), echocardiography and cardiopulmonary exercise testing (CPET). Significant myocardial ischaemia was evaluated in all subjects using the vasodilatory myocardial perfusion test. The primary endpoint was the univariate predictive association between the maximum rate of oxygen consumption attainable during physical exertion by VO2 max and the imaging measures.

Results: A total of 102 individuals were included (mean age 50±12 years, 44 males, 43%), the median time from the first infection, median [IQR],  months: 44 [38, 47]). The average measurements of the cohort are included in Table 1. On average, the subjects were normotensive and normocardic at rest. They had normal cardiac volumes and biventricular ejection fraction. About a third (28%) had persistent myocardial LGE, of which one patient had an ischaemic scar, not observed previously. In univariable analyses (Table 2), age, female sex, native T1, LV_EDVi, RVEF and E/e'  were independently associated with VO2 max at follow-up. In multivariable analysis, native T1 was the sole independent predictor of VO2 max at follow-up.

Conclusion: In individuals with no previously known structural heart disease and mild initial COVID-19 illness, age, female sex, LV volumes,  RVEF, native T1 and E/e were univariable predictors of VO2 max in long-term follow-up. In multivariable analysis, native T1 was the sole independent predictor of VO2 max at follow-up.