Maximum vasoactive-inotropic score and mortality in extremely premature, extremely low birth weight infants

Abstract

Objective: To determine the relationship between maximum vasoactive-inotropic (VIS^max) and mortality in extremely premature (<29 weeks completed gestation), extremely low birth weight (ELBW, <1000 g) infants.

Study design: Single center, retrospective, and observational cohort study.

Results: We identified 436 ELBW, <29 week, inborn infants cared for during the study period. Compared to infants with VIS^max of 0, the frequency of mortality based on VIS^max ranged from 3.3-fold to 46.1-fold. VIS^max > 30 was associated with universal mortality. Multivariable modeling that included gestational age, birth weight, and VIS^max revealed significant utility to predict mortality with negative predictive value of 87.0% and positive predictive value of 84.8% [adjusted AUROC: 0.90, (0.86-0.94)] among patients that received vasoactive-inotropic treatment.

Conclusion: VIS^max is an objective measure of hemodynamic/cardiovascular support that was directly associated with mortality in extremely premature ELBW infants. The VIS^max represents an important step towards neonatal precision medicine and risk stratification of extremely premature ELBW infants.

Figure 1.. Vasoactive-inotropic medication exposure and VIS^max by gestational age and birth weight.

A. Exposure to vasoactive-inotropic medications was inversely proportional to gestational age and ranged from 20 to 91% (p<0.001 by Chi square). B. Exposure to vasoactive-inotropic medications was inversely proportional to birth weight and ranged from 33 to 91% (p<0.001 by Chi square). C. VIS^max among only patients that received vasoactive-inotropic medications was inversely proportional to gestational age with range median values from 5 to 25 (≤23 vs all except 28; 24 vs 26, 24 vs 27; 27 vs 28; p<0.05 by Kruskal-Wallis). D. VIS^max among only patients that received vasoactive-inotropic medications was inversely proportional to birth weight with range median values from 5 to 25. (<500 vs all groups except 500-599; 500-599 vs 800-899, 500-599 vs 900-999; 600-699 vs 900-999; p<0.05 by Kruskal-Wallis).

Figure 2.. Mortality by VIS^max range.

All-cause mortality varied significantly by 5 point VIS^max intervals and ranged from 2.1% (VIS^max = 0) to 100% (VIS^max >30) (p<0.001 by Chi square).

Figure 3.. Modeling mortality risk using VIS^max among those that received vasoactive-inotropic medications.

A. Spearman’s rank correlation coefficients between variables included in the multivariable regression model. A coefficient of 0.64 was found between death and VIS^max (p<0.001). B. Multivariable logistic regression to determine the relationship between death and VIS^max adjusted for gestational age and birth weight yielded a negative predictive value of 87.0% and positive predictive value of 84.8%. C. Adjusted AUROC for mortality was 0.90, (95% confidence intervals 0.86-0.94).