Relation of Right Atrial Strain to Mortality in Infants With Single Right Ventricles

Abstract

We explored associations of surveillance testing in infants with single right ventricle (sRV) physiology with clinical outcomes. This prospective, single-center study included patients with sRV who had initial palliative surgery (September 2019 to December 2020). Echocardiograms and B-type naturetic peptide (BNP) obtained as a pair within 24hours as part of clinical care were included. The primary outcome was death/heart transplant. Secondary outcomes included interstage duration of milrinone use, hospital length of stay, and no digoxin use. sRV functional assessment (subjective grade, fractional area change, tricuspid annular plane systolic excursion, global longitudinal strain, right atrial strain [RAS]) was performed offline. Associations between echocardiography, BNP, and clinical outcomes were determined. Of 26 subjects (47 encounters), 20 had hypoplastic left heart syndrome (77%). Median age at data collection was 50days (interquartile range 26 to 90). In most encounters (73%), sRV function was subjectively normal. Median BNP was 332pg/ml (interquartile range 160 to 1,085). A total of 5 patients (19%) met the primary outcome and had lower RAS (14.1 vs 21.3, p=0.038), but all other parameters were similar to transplant-free survivors. RAS (16.1%, 0.83) had the highest area under curve, followed by global longitudinal strain (-14.4%, 0.77). Higher RAS was associated with fewer days on milrinone (coefficient -1.37, 95% confidence interval [CI] -2.54 to -0.20, p=0.02) and higher odds of digoxin use (odds ratio 1.09, 95% CI 1.01 to 1.18, p=0.047). Higher BNP was only associated with a lower odds of digoxin use (odds ratio 0.69, 95% CI 0.5 to 0.96, p=0.03). In conclusion, RAS is a potentially important imaging marker in infants with sRV and merits further investigation in larger studies.