Evaluation of renal artery stenosis: Comparison of angiography with invasive blood pressure measurement and Doppler ultrasound.

Purpose: In the procedure of renal artery angioplasty, the angiographically measured degree of stenosis should be compared with the intraarterial tran sstenotic blood pressure gradient and pre-interventional Doppler findings. Methods: In a total of 46 renal arteries in 35 patients with renovascular h ypertension. the angiographic-morphological parameters: "linear", "geometri c" and "densitometric" degree of stenosis are compared with the invasive tr ansstenotic blood pressure gradient and the pre-interventional Doppler ultr asound. Results: All angiographically determined degrees of stenosis ("line ar", "geometric" and "densitometric") correlate - moderately - with the tra nsstenotic blood pressure gradient (correlation coefficients: 0.67 ("linear "), 0.65 ("geometric") and 0.49 ("densitometric"), each versus systolic pre ssure gradient, respectively). Stenoses that are angiographically ciassifie d as "low grade" (< 50%) nevertheless have a high number of high transsteno tic pressure gradients: 21 of 22 show systolic values greater than or equal to 10 mmHg, 13 of 22 even greater than or equal to 30 mmHg. All stenoses D oppler sonographically classified as "high or very high grade" (V-max,V-sys t greater than or equal to 3 m/s) are confirmed by angiography and/or press ure measurement. Conclusions: Angiography has the tendency to underestimate the degree of renal artery stenosis, especially in "low grade" stenoses (< 50 %). However, in those greater than or equal to 50 % a high transstenoti c blood pressure gradient can be taken for granted. If the angiographic deg ree of stenosis seems uncertain, we recommend measurement of blood pressure gradient.