Assessment of Renal Artery Stenosis Severity by Pressure Gradient Measurements
Key result
Renal artery stenosis with Pd/Pa <0.90 triggers up to a ~350% increase in plasma renin.
- 346 ± 145% increase
- P=0.006
- n=15
Why the study?
Does the severity of renal artery stenosis, measured by transstenotic pressure gradient (Pd/Pa), determine the up-regulation of renin production?
Population
15 patients with renal artery stenosis undergoing unilateral stenting
Comparison
Graded stenoses created by progressive balloon… vs Baseline/unobstructed state (Pd/Pa >0.90)
Design
Other
Follow-up
10 min per step
Authors
Discussion
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Implication
A Pd/Pa ratio of 0.90 is the physiological threshold below which renal artery stenosis induces renin up-regulation, which may help select patients for renal angioplasty.
Key Points
- The aim is to define significant renal artery stenosis that induces arterial hypertension.
- Transstenotic pressure measurements in 15 patients before and after stenting.
- Balloon catheter created graded stenoses with P_d/P_a ratios from 1.0 to 0.5.
- Plasma renin concentration was measured at each stenosis level.
- No significant change in plasma renin with P_d/P_a >0.90.
- When P_d/P_a <0.90, renin increased significantly in the stenotic kidney, peaking at 346 ± 145% for P_d/P_a of 0.50 (p=0.006).
- Significant renin increase observed in the non-stenotic kidney vein (p=0.02).
Structured PICO
Does the severity of renal artery stenosis, measured by transstenotic pressure gradient (Pd/Pa), determine the up-regulation of renin production?
P
Population
15 patients with renal artery stenosis undergoing unilateral stenting and transstenotic pressure measurements.
I
Intervention
Graded stenoses created by progressive balloon inflation in the stented segment (Pd/Pa from 1.0 to 0.5, 10 min per step)
C
Comparator
Baseline/unobstructed state (Pd/Pa >0.90)
O
Outcome
Plasma renin concentration in the aorta and both renal veinssurrogate
Main Result
Effect estimate: 346 ± 145% increase
p-value: p=0.006
A Pd/Pa ratio of 0.90 is the physiological threshold below which renal artery stenosis induces renin up-regulation, which may help select patients for renal angioplasty.
Cite This Study
Bruyne et al. (2006) studied Renal artery stenosis (n=15). Graded renal artery stenosis via balloon inflation vs. Baseline or relieved stenosis was evaluated on Plasma renin concentration (346 ± 145% increase, p=0.006). A transstenotic pressure gradient (Pd/Pa) <0.90 induced a significant increase in plasma renin concentration, reaching a maximal increase of 346 ± 145% at a Pd/Pa of 0.50 (p=0.006).