Miller WL, Grill DE, Qian Q: Intravascular Volume Modulates the Outcomes Predictive Capacity of Clinical Renal Function Biomarkers in Clinically “Euvolemic” Chronic Heart Failure Patients. Kidney Dis DOI 10.1159/000502210
Plasma volume (PV) assessment by clinical means (arterial or venous blood pressure, orthostasis, pulse rate, skin turgor, capillary refilling rate, etc.) is often insensitive and unreliable. Chronic PV expansion in heart failure (HF) and chronic kidney disease (CKD) can be subtle but have important adverse consequences.
Miller and co-workers examined PV expansion by objective and quantitative tools (tracer dilution methods) in 110 adult patients with clinically stable mild-moderate HF with co-existing normo-albuminemic CKD. Substantial PV expansion compared to healthy subjects was evident in 76% of the cohort. Left ventricular ejection fraction ranged from 14–70%, so both heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) were represented in the cohort. Estimated glomerular filtration rate (eGFR) ranged from 30–66ml/min/1.73m2 (interquartile range). About 55% of the subjects had sever PV expansion (26%+ above normal PV) and these subjects had much higher NT-proBNP levels.
Not surprisingly, patients with lower eGFR levels had lower event free survival (cardiovascular death or hospitalization), especially in those with concomitant severe PV expansion. Anemia, unrelated to the dilutional effect of PV expansion was also a risk factor. The one-time assessment of PV status and the lack of a separate analysis of HFrEF and HFpEF are weaknesses of the study design, in my opinion.
Nevertheless, several “take-home” messages emerge:
- Subclinical PV expansion is very common in clinically “euvolemic” mild-moderated HF with concomitant CKD
- Standard biomarkers for prediction of cardiovascular risk in such subjects is influenced by the status of the PV
- Quantitative assessment of the degree of PV expansion in such patients may be a useful tool to refine the risk of subsequent risk of cardiovascular events or hospitalization.
Quoted Karger Article