Department of Internal Medicine.
CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre (MUMC+), Maastricht.
J Hypertens. 2018 Aug;36(8):1729-1735. doi: 10.1097/HJH.0000000000001755.
Fibromuscular dysplasia (FMD) can be classified in a multifocal and a unifocal subtype. As unifocal FMD generally leads to more severe hypertension at younger age, we hypothesized that renal hemodynamics are more disturbed in unifocal renal artery FMD as compared with multifocal FMD, leading to increased renin secretion.
We measured renal blood flow (Xenon washout method), renin secretion, and glomerular filtration rate per kidney in 101 patients with FMD (26 unifocal and 75 multifocal), all off medication and prior to balloon angioplasty.
We found that renal blood flow and glomerular filtration were substantially lower in kidneys with unifocal FMD as compared with multifocal FMD. In the affected kidney from patients with unilateral FMD for example, mean renal blood flow was 173 ± 77 in unifocal vs. 244 ± 79 ml/100 g kidney/min in multifocal FMD (P = 0.013). Moreover, lateralization in renin secretion was only observed in a subset of patients with unifocal FMD, but not in any of the patients with multifocal FMD.
These findings suggest that the impact of unifocal FMD lesions on the kidney is more severe, resulting in a classical pattern of renovascular hypertension. In multifocal FMD, however, renal blood flow is more preserved, local renin secretion is not increased, and the association between renin levels and blood pressure is inverse. These differences may explain the often more severe clinical presentation and higher success rate of revascularization in unifocal FMD, but also suggest that the pathophysiological mechanisms leading to hypertension may differ between these two disease entities.
纤维肌性发育不良（FMD）可分为多灶性和单灶性亚型。由于单灶性 FMD 通常导致年轻时更严重的高血压，我们假设单灶性肾动脉 FMD 比多灶性 FMD 更扰乱肾血流动力学，导致肾素分泌增加。
我们在 101 例 FMD 患者（26 例单灶性和 75 例多灶性）中测量了肾血流（氙气洗脱法）、肾素分泌和单侧 FMD 患者的单侧肾脏肾小球滤过率，所有患者均未服用药物且未行球囊血管成形术。
我们发现单灶性 FMD 肾脏的肾血流和肾小球滤过率明显低于多灶性 FMD。例如，单侧 FMD 患者的受影响肾脏的平均肾血流在单灶性 FMD 中为 173±77ml/100g 肾脏/分钟，而在多灶性 FMD 中为 244±79ml/100g 肾脏/分钟（P=0.013）。此外，只有一部分单灶性 FMD 患者出现肾素分泌的偏侧化，而多灶性 FMD 患者则没有。
这些发现表明，单灶性 FMD 病变对肾脏的影响更为严重，导致典型的肾血管性高血压。然而，在多灶性 FMD 中，肾血流得到更好的保留，局部肾素分泌不增加，肾素水平与血压之间的关联呈负相关。这些差异可能解释了单灶性 FMD 通常更严重的临床表现和更高的血管再通成功率，但也表明导致高血压的病理生理机制可能在这两种疾病实体之间有所不同。
