The renal arterial resistance index: a marker of renal function with an independent and incremental role in predicting heart failure progression.
OBJECTIVE
The renal arterial resistance index (RRI) is a measure of renal blood flow obtained by Doppler ultrasonography, which has been demonstrated to reflect both vascular and parenchymal renal abnormalities. The aim of the study was to evaluate clinical correlates and the prognostic relevance of RRI in a group of patients affected by chronic heart failure (CHF).


RESULTS
We enrolled 250 CHF outpatients in a stable clinical condition and receiving conventional therapy. Peak systolic velocity and end-diastolic velocity of a segmental renal artery were obtained by pulsed Doppler flow. Then the RRI was calculated. Standard renal function assessment was obtained by the measurement of creatinine serum levels and the estimation of the glomerular filtration rate (GFR). During follow-up (21.4 ± 11.3 months), 41 patients experienced heart failure progression (hospitalization and/or heart transplantation and/or death due to worsening heart failure). Considered as a continuous variable, RRI was associated with events at univariate [hazard ratio (HR) 1.14; 95% confidence interval (CI) 1.09-1.19; P < 0.001] as well as at multivariate Cox regression analysis (HR 1.08; 95% CI 1.02-1.13; P = 0.004) after correction for independent predictors of the reference model. When the RRI was added to the reference model including GFR, a significant improvement of reclassification according to both category-free net reclassification improvement (NRI, 47%; 95% CI 13-80%; P = 0.006) and integrated discrimination improvement (IDI, 0.034; 95% CI 0.006-0.061; P = 0.016) was observed.


CONCLUSIONS
Quantification of arterial renal perfusion provides a new parameter that independently predicts CHF patient outcome, thus strengthening its possible role in current clinical practice in order to better characterize renal function and stratify patients' prognosis.
Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy.
Marco Matteo
MM
Ciccone
Massimo
M
Iacoviello
Loreto
L
Gesualdo
Agata
A
Puzzovivo
Valeria
V
Antoncecchi
Annalisa
A
Doronzo
Francesco
F
Monitillo
Gaetano
G
Citarelli
Valeria
V
Paradies
Stefano
S
Favale
D000368:Aged; D059347:Cardio-Renal Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology; D002908:Chronic Disease; D015331:Cohort Studies; D018450:Disease Progression; D018618:Echocardiography, Doppler, Color; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012077:Renal Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018617:Ultrasonography, Doppler, Pulsed; D014655:Vascular Resistance / Q000502:physiology*
Cardiorenal syndrome; Chronic heart failure; Prognosis; Renal function