Pulmonary Pressures and Death in Heart Failure: A Community Study
What is the association between pulmonary artery systolic pressure (PASP) assessed by Doppler echocardiography and mortality after adjustment for established risk factors?
Between 2003 and 2010, Olmsted County residents with heart failure (HF) prospectively underwent assessment of ejection fraction, diastolic function, and PASP by Doppler echocardiography. Survival was analyzed with the Kaplan-Meier method according to PASP tertiles and was compared by the log-rank test. Cox proportional hazards regression was used to examine the association between PASP and all-cause death and cardiovascular (CV)-specific death, univariately, and while controlling for baseline characteristics.
PASP was recorded in 1,049 of 1,153 patients (mean age 76 ± 13; 51% women). Median PASP was 48 mm Hg (25th to 75th percentile: 37.0-58.0). There were 489 deaths after a follow-up of 2.7 ± 1.9 years. There was a strong positive graded association between PASP and mortality. Increasing PASP was associated with an increased risk of death (hazard ratio, 1.45; 95% confidence interval, 1.13-1.85 for tertile 2; hazard ratio, 2.07; 95% confidence interval, 1.62-2.64 for tertile 3, versus tertile 1), independently of age, sex, comorbidities, ejection fraction, and diastolic function. Adding PASP to models including these clinical characteristics resulted in an increase in the c-statistic from 0.704 to 0.742 (p = 0.007), an integrated discrimination improvement gain of 4.2% (p < 0.001), and a net reclassification improvement of 14.1% (p = 0.002), indicating that PASP improved prediction of death over traditional prognostic factors. All results were similar for CV death.
The authors concluded that among community patients with HF, PASP strongly predicts death and provides incremental and clinically relevant prognostic information independently of known predictors of outcomes.
This study suggests that pulmonary pressures can be readily assessed by Doppler echocardiography among patients with HF in the community, and that pulmonary hypertension or elevated PASP was a strong predictor of all-cause death and CV death independently of other known predictors, including diastolic function measures and B-type natriuretic peptide. Overall, these data support the concept that pulmonary hypertension may be a central determinant in the outcome of HF and may, therefore, represent a potential therapeutic target. A significant limitation of the current study is the lack of investigation between the findings of pulmonary hypertension and measures of right ventricular function since such an investigation may have yielded further discriminatory insight into the clinical value of these observations. Additional studies are warranted to have a clearer understanding of effects of pulmonary hypertension on the right ventricle for more precise prognostic and therapeutic insight.
Keywords: Cause of Death, Prognosis, Follow-Up Studies, Heart Failure, Ventricular Function, Risk Factors, Pulmonary Artery, Echocardiography
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