A score based on 3 indicators can be used to predict if surgery will cure renovascular hypertension due to unilateral vascular involvement.
Indicators:
(1) plasma renin activity in aorta or inferior vena cava below renal veins
(2) renal vein PRA relative to arterial PRA in stenotic kidney
(3) renal vein PRA relative to arterial PRA in contralateral kidney
Patient Preparation, Specimen Collection and Testing: As for plasma renin activity studies (13.19.02).
In addition, to interpret renin activity urine studies to evaluate 24 hour sodium excretion are needed.
Factor |
Finding |
Score |
---|---|---|
peripheral plasma renin activity |
elevated |
3 |
|
normal |
0 |
|
subnormal |
-3 |
((V-A) / A) for stenotic kidney |
>= 0.70 |
4 |
|
0.48 - 0.69 |
2 |
|
< 0.48 |
-3 |
((V-A) / A) for contralateral kidney |
<= 0.23 |
3 |
|
0.24 - 0.38 |
1 |
|
> 0.38 |
-3 |
Evaluating peripheral renin activity versus urinary sodium excretion in mEq/day (Figure 2, page 405, Vaughan, 1973; Figure 1, page 443, Brunner, 1972): The normal renin activity difficult to assess (patient preparation for determining relative PRA enhances renin activity; normal range higher in children under 10; affected by posture)
Urine Sodium Excretion |
Upper Limit of the Normal Reference Range for Renin |
---|---|
< 25 mEq sodium/day |
unlimited |
25 - 49.9 mEq sodium/day |
(0.0019733 * ((sodium excretion) ^ 2)) - (0.34 * (sodium excretion)) + 19.166667 |
50 - 212 mEq sodium/day |
(- 4.2 * 10^(-7) * ((sodium excretion) ^3)) + (0.0003213 * ((sodium excretion) ^ 2)) - (0.085104 * (sodium excretion)) + 10.605739 |
> 212 mEq sodium/day |
3 ng/mL/hr |
Urine Sodium Excretion |
Lower Limit of the Normal Reference Range for Renin |
---|---|
< 25 mEq sodium/day |
(0.001328 * ((sodium excretion) ^ 2)) - (0.1372 * (sodium excretion)) + 5.73 |
25 - 212 mEq sodium/day |
(- 5.1 * 10^(-7) * ((sodium excretion) ^3)) + (0.0002677 * ((sodium excretion) ^ 2)) - (0.054303 * (sodium excretion)) + 4.2991603 |
> 212 mEq sodium/day |
0 |
Interpretation:
• maximum score 10
• minimum score -9
Criteria for Evaluating Response to Surgery |
Diastolic Pressure after Surgery |
Change in Diastolic Pressure from Preoperative Levels |
---|---|---|
cured |
<= 90 mm Hg |
>= 10 mm Hg drop |
improved |
> 90 mm Hg |
>= 15% decrease |
failed |
> 90 mm Hg |
< 15% decrease |
Purpose: To attempt to identify a kidney affected by renovascular disease and to whether surgery is likely to be effective.
Specialty: Endocrinology, Clinical Laboratory, Nephrology, Cardiology
Objective: severity, prognosis, stage, selection
ICD-10: I12.9,