Left ventricular stroke work reserve as prognostic marker in severe heart failure

We sought to determine whether an invasive approach based on Swan-Ganz catheterization, coupled with a pharmacologic stressor, might help stratify prognosis in patients with severe heart failure and uniformly depressed indices of cardiac function.

We studied 31 unselected consecutive patients with scalar doses of dobutamine (2.5-10 microg/kg/min) after baseline hemodynamic evaluation. Changes in stroke work index (SWI) from baseline to peak effect (stroke work reserve, SWR) were recorded, and patients classified as responders (SWR above the median) or non-responders to dobutamine (SWR below the median). One-year follow-up data were recorded.

All patients completed the dobutamine challenge test without complications. Dobuta-mine increased SWI from 17+/-9 to 26+/-13 mg/ beat/m2 (P<0.0001 vs baseline), with a median increase of 6.4 g/beat/m2. Basal SWI was not related to stroke work reserve. The only predictor of response to dobutamine was a smaller left ventricular end-diastolic volume (135+/-28 vs 205+/-90 mL/m2; P=0.007). After 1 year, only 7 patients were alive, while 10 had successful transplantation. Transplant-free survival was 47% in responders vs 0% in non responders (P=0.007). At multivariate analysis, none of baseline hemodynamic parameters was predictive of survival. Only age and a SWR above the median were significant independent predictors of survival in this model.

This study allows us to draw the following conclusions: 1) 1-year mortality in severe heart failure remains extremely high; 2) baseline hemodynamics dos not predict survival; 3) a positive response to dobutamine identifies a subgroup with significant lower mortality at 1 year; 4) this response is an independent predictor of survival and is more likely to occur in the presence of a less dilated left ventricle.