Abstract Body (Do not enter title and authors here):
Introduction: Pressure-adjusted heart rate (PAHR) provides an integrated assessment of hemodynamic decompensation in critically ill patients.
Research Question: How does PAHR perform in critically ill patients with cardiovascular disease?
Aims: We sought to evaluate the prognostic value of PAHR on mortality in patients admitted to the cardiovascular intensive care unit (CICU).
Methods: A retrospective cohort of patients admitted to the CICU at a tertiary-care academic institution, between 2007 and 2018, who had a transthoracic echocardiogram (TTE) within one day of admission were evaluated. Heart rate (HR), right atrial pressure (RAP), and mean arterial pressure (MAP), obtained from TTE, were used to calculate PAHR as RAP * HR / MAP.
Results: Among 5411 patients included for analysis (median age 70.1 years, 38.6% female, 92.4% White), higher PAHR was associated with greater severity of acute illness, burden of comorbidities, and use of critical care therapies. Median values (25^th percentile, 75^th percentile) for HR were 73.0 (63.0, 87.0) beats per minute (bpm), RAP 10.0 (5.0, 14.0) mm Hg, and MAP 81.3 (72.3, 91.7) mm Hg. Median PAHR was significantly higher among patients who died during hospitalization (14.3 bpm vs 6.8 bpm, p <0.001). In addition, TTE measurements of biventricular function, intracardiac filling pressures, and cardiac output were worse among those with higher PAHR (Table). Adjusted in-hospital mortality increased incrementally with higher PAHR, regardless of admission diagnosis, biventricular function, and critical care therapies (adjusted odds ratio [OR] 1.03 per 1 bpm higher, 95% confidence interval [CI] 1.01-1.05, p = 0.001; adjusted OR per quartile 1.37, 95% CI 1.19-1.59, p <0.001, Figure 1). Similarly, one-year mortality increased incrementally with higher PAHR (adjusted hazard ratio 1.03 per 1 bpm higher, 95% CI 1.02-1.04, p <0.001, Figure 2). When compared to component values, including the modified shock index, which is defined by HR / MAP, PAHR had the highest area under the curve (C-statistic 0.75).
Conclusions: PAHR is a readily determinable composite measure of filling pressures and vascular resistance that enhances clinical risk stratification of critically ill patients by TTE. Among a diverse cohort of CICU patients, higher PAHR was associated with greater in-hospital and one-year mortality, regardless of admission diagnosis, biventricular function, or illness severity.