Global cerebral blood flow linked to cardiovascular outcomes in HF patients
MedWire News: Cerebral blood flow (CBF) may be associated with the development of long-term cardiovascular outcomes in systolic heart failure (HF) patients, Korean researchers say.
Global CBF may be useful for determining the prognosis of systolic HF patients and in the selection of heart transplantation patients, report Min-Seok Kim (University of Ulsan College of Medicine, Seoul) and co-authors in the European Heart Journal.
Currently, the best predictor of survival in HF patients is peak oxygen consumption rate (VO2), which is measured using a cardiopulmonary exercise test (CPET). However, many physicians are reluctant to use this method due to patient comorbidities. CPET is also thought to increase the risk for myocardial infarction.
To investigate whether global CBF levels could be used prognostically in HF, Kim and team conducted a prospective observational study that involved 224 systolic HF patients with a left ventricular ejection fraction of 35% or less. Their global CBF levels were measured using radionuclide angiography. The team also obtained patients' clinical, biochemical, echocardiographic, and exercise data.
During a median follow-up period of 36 months, 52 (23.2%) patients died or underwent urgent heart transplantation.
Multivariate analysis revealed that global CBF, minute ventilation/carbon dioxide production (VE/VCO2) slope, levels of serum sodium, and serum creatinine were associated with cardiac death or urgent heart transplantation. Having a New York Heart Association functional class III or greater and a symptom duration of 12 months or more also increased the risk for this outcome.
Patients with a CBF level lower than 35.4 ml/min/100 g were at a significantly increased risk for death or urgent heart transplantation (hazard ratio=2.47, p=0.0035).
The authors point out that this finding is particularly relevant for patients who cannot undergo exercise testing due to being in poor medical condition.
Further analysis revealed that addition of global CBF to a prognostic model including the VE/VCO2 slope increased the C-index for the prediction of adverse outcomes from 0.826 to 0.837. However, this increase did not reach statistical significance.
"These findings suggest that global CBF data may assist in identifying advanced systolic HF patients who require urgent transplantation," conclude the authors.
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By Piriya Mahendra