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J Am Coll Cardiol. 2006 Nov 7;48(9):1851-5. Epub 2006 Oct 17.

Assessment of renal artery stenosis severity by pressure gradient measurements.

Author information

1
Cardiovascular Center Aalst, OLV Clinic, Aalst, Belgium. bernard.de.bruyne@olvz-aalst.be

Abstract

OBJECTIVES:

The purpose of this study was to define "significant" renal artery stenosis (i.e., a stenosis able to induce arterial hypertension).

BACKGROUND:

The degree of renal artery stenosis that justifies an attempt at revascularization is unknown.

METHODS:

In 15 patients, transstenotic pressure measurements were obtained before and after unilateral stenting. After stenting, graded stenoses were created in the stented segment by progressive inflation of a balloon catheter. Stenosis severity was expressed as the ratio of distal pressure (P(d)) corrected for aortic pressure (P(a)). Balloon inflation pressure was adjusted to create 6 degrees of stenosis (P(d)/P(a) from 1.0 to 0.5, each step during 10 min). Plasma renin concentration was measured at the end of each step in the aorta and in both renal veins.

RESULTS:

For a P(d)/P(a) ratio >0.90, no significant change in plasma renin concentration was observed. However, when P(d)/P(a) became <0.90, a significant increase in renin was observed in the renal vein of the stenotic kidney, finally reaching a maximal increase of 346 +/- 145% for P(d)/P(a) of 0.50 (p = 0.006). These values returned to baseline when the stenosis was relieved. In addition, plasma renin concentration increased significantly in the vein from the non-stenotic kidney (p = 0.02).

CONCLUSIONS:

In renal artery stenoses, a P(d)/P(a) ratio of 0.90 can be considered a threshold value below which the stenosis is likely responsible for an up-regulation of renin production and, thus, for renovascular hypertension. These findings might contribute to better patient selection for renal angioplasty.

PMID:
17084261
DOI:
10.1016/j.jacc.2006.05.074
[Indexed for MEDLINE]
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