The probability of renal artery stenosis in certain patients with hypertension can be predicted using a rule based on clinical data. This can be used to appropriately select patients for angiography, which is both expensive and invasive. This study was done at the Hospital Dijkzigt, Rotterdam, the Netherlands.
NOTE: The clinical rule is based on an equation using variables derived from a multivariate logistic regression analysis, as described in the next section.
Patients selected: 18 to 75 years of age with preserved renal function (serum creatinine <= 200 µmol/L) and either:
(1) drug resistant hypertension, or
(2) increase in serum creatinine concentration during therapy with an angiotensin-converting enzyme (ACE) inhibitor
Parameters used for the clinical score:
(1) age in years
(2) gender
(3) smoking history
(4) signs and symptoms of atherosclerotic vascular disease
(5) duration of hypertension
(6) body mass index (BMI)
(7) presence of abdominal bruit
(8) serum creatinine
(9) serum cholesterol and/or history of cholesterol lowering drug therapy
|
Parameter |
Finding |
Never Smoked |
History of Smoking |
|---|---|---|---|
|
age in years |
20 |
0 |
3 |
|
|
30 |
1 |
4 |
|
|
40 |
2 |
4 |
|
|
50 |
3 |
5 |
|
|
60 |
4 |
5 |
|
|
70 |
5 |
6 |
|
gender |
male |
0 |
0 |
|
|
female |
2 |
2 |
|
signs and symptoms of atherosclerotic vascular disease |
absent |
0 |
0 |
|
|
present |
1 |
1 |
|
onset of hypertension |
within <= 2 years |
1 |
1 |
|
|
more than 2 years |
0 |
0 |
|
body mass index |
< 25 kg/m^2 |
2 |
2 |
|
|
>= 25 kg/m^2 |
0 |
0 |
|
abdominal bruit |
absent |
0 |
0 |
|
|
present |
3 |
3 |
|
serum creatinine |
40 µmol/L |
0 |
0 |
|
|
60 µmol/L |
1 |
1 |
|
|
80 µmol/L |
2 |
2 |
|
|
100 µmol/L |
3 |
3 |
|
|
150 µmol/L |
6 |
6 |
|
|
200 µmol/L |
9 |
9 |
|
serum cholesterol |
<= 6.5 mmol/L and not on cholesterol lowering therapy |
0 |
0 |
|
|
<= 6.5 mmol/L and on cholesterol lowering therapy |
1 |
1 |
|
|
> 6.5 mmol/L |
1 |
1 |
Table 2, page 708
where:
• Signs or symptoms of atherosclerotic vascular disease include: femoral or carotid bruit, angina pectoris, claudication, myocardial infarction, cerebrovascular accident, or vascular surgery.
• Intermediate values for age and serum creatinine are to be linearly interpolated:
points for age if nonsmoker =
= (0.1 * (age in years)) - 2
The points for age if smoker is nonlinear, so will assign points from a table, rounding to the next decade (for example: 25 to 34 rounded to 30).
points for serum creatinine =
= (0.0565 * (serum creatinine in µmol/L)) - 2.4373
score =
= SUM(values for parameters present)
Interpretation:
• minimum score: 0
• maximum score if nonsmoker: 24
• maximum score if current or past smoker: 25
|
Score |
Probability of Renal Artery Stenosis |
|---|---|
|
0 |
0% |
|
1 |
0% |
|
2 |
0% |
|
3 |
0.5% |
|
4 |
1% |
|
5 |
2% |
|
6 |
3% |
|
7 |
5% |
|
8 |
8% |
|
9 |
12% |
|
10 |
18% |
|
11 |
25% |
|
12 |
38% |
|
13 |
50% |
|
14 |
62% |
|
15 |
72% |
|
16 |
82% |
|
17 |
88% |
|
18 |
92% |
|
19 |
95% |
|
20 |
97% |
|
21 |
98% |
|
22 |
99% |
|
23 |
99.5% |
|
24 |
100% |
|
25 |
100% |
estimated from Figure 2, page 708
Limitations:
• The clinical rule should not be applied if secondary causes of hypertension such as renal parenchymal disease are present, or if the patient has impaired renal function (as indicated by a serum creatinine > 200 µmol/L).
Purpose: To predict the risk of renal artery stenosis in an adult with hypertension not responding to therapy appropriately by using a clinical score.
Specialty: Nephrology, Clinical Laboratory
Objective: clinical diagnosis, including family history for genetics
ICD-10: I70.1, I70.1, I70.1, N28,
