Abstract 2308: Does Peak Oxygen Consumption add to the Seattle Heart Failure Model?
OBJECTIVES: The Seattle Heart Failure Model (SHFM - SeattleHeartFailureModel.org) is a validated multivariate risk model that uses New York Heart Failure Classification to assess functional capacity rather than peak oxygen consumption (PVO2). As PVO2 has been shown to be a multivariate risk predictor in heart failure, we investigated whether the addition of PVO2 improves the predictive accuracy of the SHFM.
METHODS AND RESULTS: 1,240 outpatients evaluated for transplant at Center A (n=647, era 1990 –2006), Center B (n=498 era 1993–2006) and Center C (n=95, era 1999 –2001) had the SHFM calculated and PVO2 measured. Demographics were age (53 yrs), Male 67%, Ischemic etiology (45%), NYHA class (2.4), EF (24%), PVO2 (15.2 ml/kg/min), SBP (107 mm Hg), ACEI (78%), ARB (15%), beta blocker (60%), aldosterone blocker (33%), statin (36%), ICD (28%) and furosemide (1.5 mg/kg/day). The outcome was death/LVAD/Urgent transplant with censoring at the time of elective transplant. During 4.1 mean years of observation, there were 571 events. Both the Seattle Heart Failure Model (chi square 225, p<0.0001) and PVO2 (chi square 90, p<0.0001) were highly predictive of outcomes. The SHFM and PVO2 were modestly correlated (r=0.39, P<0.0001). In a multivariate Cox model, PVO2 added to the SHFM with a hazard ratio of 0.947 (p<0.0001) for each 1 ml/kg, similar to the hazard ratio of 0.95 for PVO2 in the Heart Failure Survival Score. Within each quartile of PVO2, the SHFM was prognostically significant (all p<0.0001). Similarly, within each quartile of the SHFM, PVO2 was significant (p=0.04 to <0.0001) The 1 year ROC were; PVO2 (0.645, 95% CI 0.606 – 0.684), SHFM (0.758, 95% CI 0.721–.795) and SHFM with PVO2 (0.766, 95% CI 0.731– 0.802). The SHFM predicted vs. actual survival free of death/LVAD/UNOS 1 transplant at 1 year (86% vs. 83%), 2 years (77% vs. 73%), and 5 years (58% vs. 53%) were similar.
CONCLUSIONS: The multivariate SHFM is powerful predictor of death/LVAD/urgent transplant. Peak oxygen consumption adds prognostic information across the spectrum of the SHFM.