Stenosis of the renal artery: assessment of slowed systole in the downstream circulation with Doppler sonography.

Abstract

Slowing and dampening of systole in the arterial network distal to stenosis is a well-known Doppler sign of severe arterial stenosis. To determine whether this sign is present in boys and girls with such stenosis, intrarenal Doppler curves (acceleration index [AI] and resistive index [RI]) were compared with findings on renal arteriograms in 20 boys and girls; the AI was also measured in 10 boys and girls without renal disease. Statistical analysis of AI and RI measurements was performed. Eleven of 32 renal arteries were normal. The normal AI was 4.0-7.0; in arteries with greater than 75% stenosis, the AI was 0.7-1.7. In five arteries studied after angioplasty, the AI had changed from 0.7-1.5 to 4.0-5.6 at the first posttreatment examination (performed 28 hours to 1 week after angioplasty), and it remained normal during the 3-year follow-up period. In kidneys with stenotic arteries, the RIs were lower (0.43-0.54) than in healthy subjects (0.56-0.63). Regression and correlation coefficients of AI and RI measurements were statistically significant, and discrimination between normal arteries and those with greater than 75% stenosis was excellent.

Doppler ultrasound and renal artery stenosis: An overview

“…On the other hand, in a comprehensive review, the authors [19,34] found for AT and AI a sensitivity of 80% and 74% and a specificity of 88% and 85%, respectively. Many factors influence systolic acceleration and may make the test nonspecific.…”

Doppler Ultrasound in the Diagnosis of Renal Transplant Artery Stenosis - Value of Resistive Index

“…To overcome this, some investigators have utilized so-called dampening of the waveform distal to a significant stenosis. A pressure drop across a stenosis is reflected distally by diminished systolic velocity and prolonged systolic acceleration time (3,7,8,12,13,20). The use of the Doppler technique in suspected renal transplant artery stenosis was first introduced by REINITZ et al (1 5).…”

“…The use of acceleration time (AT), acceleration index (AI) and RI have been reported earlier (9,12,20). STAVROS et al (20) used in addition a simple pattern recognition method, in which a loss of the early systolic compliance peak/reflective wave complex was the sign of a more than 60% stenosis.…”

“…The criteria of a significant stenosis have relied on the increased Doppler frequency or velocity at the site of a stenosis and poststenotic turbulence (1,4,6,10,15,19,21). Recent reports concerning arterial stenosis of the native kidneys suggest that intrarenal Doppler waveform analysis would be useful (9,12,20).…”

Diagnostic imaging of renal artery stenosis

“…The first type manifested as a slowed rise to peak systolic velocity ('pulsus tardus phenomenon') and loss of the normally occurring early systolic velocity peak. [21][22][23][24] The second type was a lowering of the renal resistive index (peak systolic velocity/maximum end diastolic velocity). 25,26 These changes were shown to be result of a complex interaction between the resistance to flow and the compliance of the post-stenotic vessel wall.…”