Renal frame count and renal blush grade: quantitative measures that predict the success of renal stenting in hypertensive patients with renal artery stenosis.
OBJECTIVE
This study sought to identify angiographic parameters of favorable clinical response to renal artery stenting.


BACKGROUND
Stenting improves blood pressure (BP) control in patients with renal artery stenosis (RAS), but markers predicting a favorable clinical response are limited.


METHODS
Renal perfusion was quantified in hypertensive patients (BP >or=140/90 mm Hg) without RAS by determining renal frame count (RFC) (angiographic frames [30 frames/s] for contrast to reach distal renal parenchyma after initial renal artery opacification) and renal blush grade (RBG) (0: none, 1: minimal, 2: normal, 3: hyperemic parenchymal blush). It was hypothesized that stenting unilateral RAS in hypertensive patients would result in decreased RFC and increased RBG, which might predict BP reduction.


RESULTS
The RFC in 17 consecutive hypertensive patients without RAS (control group) (64.4 +/- 14.2 years, 12 male, 22 kidneys) was 20.1 +/- 5.4, whereas RBG was 2.33 +/- 0.66. In 24 consecutive hypertensive patients with unilateral RAS (study group) (72.7 +/- 11.3 years, 8 male), reduced RFC (26.6 +/- 9.1 to 21.4 +/- 6.7, p < 0.001) and increased RBG (1.63 +/- 0.71 to 2.13 +/- 0.85, p = 0.03) were observed after renal stenting. At 6 months, reduced BP (systolic BP 150.6 +/- 15.6 mm Hg to 128.6 +/- 15.5 mm Hg, p < 0.001; diastolic BP 77.2 +/- 15.6 mm Hg to 68.3 +/- 10.4 mm Hg, p = 0.022) without change in number of hypertensive medications was observed. Clinical responders (systolic BP reduction >15 mm Hg) had a greater decrease in RFC (7.7 +/- 4.6 vs. 1.7 +/- 5.1, p = 0.009) and 78.6% of patients with >4 RFC decrease were responders (p = 0.024).


CONCLUSIONS
This study shows that quantitative indices of renal perfusion (RFC and RBG) are impaired in patients with RAS and improve after stenting, and that RFC reduction is associated with BP reduction.
Mahmud
Ehtisham
E
Division of Cardiovascular Medicine, School of Medicine, University of California, San Diego, California 92103-8784, USA. emahmud@ucsd.edu
Smith
Thomas W R
TW
Palakodeti
Vachaspathi
V
Zaidi
Owais
O
Ang
Lawrence
L
Mitchell
C Robinson
CR
Zafar
Nayab
N
Bromberg-Marin
Guilherme
G
Keramati
Shahin
S
Tsimikas
Sotirios
S
D000368:Aged; D000369:Aged, 80 and over; D000800:Angioplasty, Balloon / Q000295:instrumentation*; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001783:Blood Flow Velocity; D002932:Cineangiography; D005260:Female; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012078:Renal Artery Obstruction / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D012079:Renal Circulation; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015607:Stents; D016896:Treatment Outcome
D000959:Antihypertensive Agents