De Bruyne Bernard, Manoharan Ganesh, Pijls Nico H J, Verhamme Katia, Madaric Juraj, Bartunek Jozef, Vanderheyden Marc, Heyndrickx Guy R
Cardiovascular Center Aalst, OLV Clinic, Aalst, Belgium.
J Am Coll Cardiol. 2006 Nov 7;48(9):1851-5. doi: 10.1016/j.jacc.2006.05.074. Epub 2006 Oct 17.
The purpose of this study was to define "significant" renal artery stenosis (i.e., a stenosis able to induce arterial hypertension).
The degree of renal artery stenosis that justifies an attempt at revascularization is unknown.
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.
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).
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.
本研究的目的是定义“显著的”肾动脉狭窄（即能够诱发动脉高血压的狭窄）。
证明血管重建术尝试合理的肾动脉狭窄程度尚不清楚。
对15例患者在单侧支架置入前后进行跨狭窄压力测量。支架置入后，通过球囊导管逐渐充盈在支架段制造分级狭窄。狭窄严重程度用经主动脉压力校正的远端压力（P(d)）比值表示。调整球囊充盈压力以制造6级狭窄（P(d)/P(a)从1.0至0.5，每级持续10分钟）。在主动脉及双侧肾静脉的每个步骤结束时测量血浆肾素浓度。
当P(d)/P(a)比值>0.90时，未观察到血浆肾素浓度有显著变化。然而，当P(d)/P(a)<0.90时，在狭窄肾的肾静脉中观察到肾素显著增加，最终在P(d)/P(a)为0.50时达到最大增幅346±145%（p = 0.006）。当狭窄解除时，这些值恢复到基线水平。此外，非狭窄肾静脉中的血浆肾素浓度也显著增加（p = 0.02）。
在肾动脉狭窄中，P(d)/P(a)比值0.90可被视为一个阈值，低于该阈值，狭窄可能导致肾素产生上调，进而导致肾血管性高血压。这些发现可能有助于更好地选择肾血管成形术的患者。
