Onuigbo M A C, Onuigbo N T C
College of Medicine, Mayo Clinic, Rochester, MN, USA.
QJM. 2008 Jul;101(7):519-27. doi: 10.1093/qjmed/hcn039. Epub 2008 Mar 28.
The current US chronic kidney disease (CKD)/end stage renal disease (ESRD) epidemic, coincident with the increasing application of renin angiotensin aldosterone system (RAAS) blockade, has raised concerns of iatrogenic renal failure. The US population is an ageing one, further raising the possibility of increasing renal artery stenosis (RAS) in our patients. Current literature regarding worsening renal failure in CKD patients with RAS is based almost wholly on retrospective studies, and therefore may be poorly understood.
To prospectively examine the syndrome of worsening renal failure in CKD patients with hemodynamically significant RAS concurrently on RAAS blockade.
Prospective cohort study.
Between September 2002 and February 2005, CKD patients, concurrently on RAAS blockade, with RAS >70% by magnetic resonance angiography, who presented with accelerated azotemia (> or =25% increase in baseline serum creatinine) were consecutively enrolled. In addition to standard nephrology care, RAAS blockade was discontinued and renal percutaneous transluminal angioplasty (PTA)/stenting performed according to standard guidelines. Renal function as measured by MDRD-derived eGFR (estimated glomerular filtration rate) was monitored.
Twenty-six Caucasian patients were enrolled-M:F = 10:16, mean age 75.3 years. Prior duration of RAAS blockade was 20.2 months. Known risk factors were absent in 15/26. Unilateral RAS with dual kidneys was common-19/26. Five patients, with higher baseline creatinine-2.1 +/- 0.6 vs. 1.5 +/- 0.4 mg/dl, P = 0.013, progressed to ESRD; 4/5 ESRD patients died after 6.3 months. Excluding the 5 with ESRD, and 2 lost to follow-up, in 19 patients, eGFR increased from 27.8 +/- 9.5 to 39.7 +/- 14.9 ml/min/1.73 m(2) BSA (P = 0.001), 26.4 months after stopping RAAS blockade. In these same 19 patients, mean arterial blood pressure improved from 100 +/- 9 to 92 +/- 10 mmHg, with 8 patients requiring additional antihypertensive substitutions. Renal PTA/stenting further improved eGFR in 7/9 patients.
Contrary to previous retrospective reports, we observed that renal failure/ESRD in this older CKD patient population is common in patients with unilateral RAS lesions with dual kidneys; precipitating risk factors are often absent, and progression to ESRD with increased mortality is not infrequent. Older age, higher baseline creatinine (>2.0) and/or lower eGFR (<35) predicted ESRD. eGFR improved following discontinuation of RAAS blockade, generally. Furthermore, in selected patients, renal PTA and stent placement led to additional improvements in eGFR. Our observations call for further studies.
当前美国慢性肾脏病（CKD）/终末期肾病（ESRD）的流行，恰逢肾素血管紧张素醛固酮系统（RAAS）阻滞剂应用的增加，引发了对医源性肾衰竭的担忧。美国人口老龄化，这进一步增加了我们患者中肾动脉狭窄（RAS）加重的可能性。目前关于RAS的CKD患者肾衰竭恶化的文献几乎完全基于回顾性研究，因此可能理解不足。
前瞻性研究在接受RAAS阻滞剂治疗的同时合并血流动力学显著RAS的CKD患者中肾衰竭恶化综合征。
前瞻性队列研究。
在2002年9月至2005年2月期间，连续纳入接受RAAS阻滞剂治疗、磁共振血管造影显示RAS>70%且出现加速氮质血症（基线血清肌酐升高≥25%）的CKD患者。除了标准的肾脏病护理外，停用RAAS阻滞剂，并根据标准指南进行肾经皮腔内血管成形术（PTA）/支架置入术。监测通过MDRD衍生的估算肾小球滤过率（eGFR）测量的肾功能。
纳入了26例白种人患者，男:女 = 10:16，平均年龄75.3岁。之前接受RAAS阻滞剂治疗的持续时间为20.2个月。26例中有15例无已知危险因素。双侧肾脏单侧RAS很常见，为19/26。5例患者基线肌酐较高，分别为2.1±0.6 vs. 1.5±0.4 mg/dl，P = 0.013，进展为ESRD；4/5例ESRD患者在6.3个月后死亡。排除5例ESRD患者和2例失访患者，19例患者在停用RAAS阻滞剂26.4个月后，eGFR从27.8±9.5增加到39.7±14.9 ml/min/1.73 m²体表面积（P = 0.001）。在这19例相同患者中，平均动脉血压从100±9改善到92±10 mmHg，8例患者需要额外的降压替代治疗。肾PTA/支架置入术使7/9例患者的eGFR进一步改善。
与之前的回顾性报告相反，我们观察到在这个老年CKD患者群体中，肾衰竭/ESRD在双侧肾脏单侧RAS病变患者中很常见；往往不存在促发危险因素，进展为ESRD且死亡率增加并不罕见。高龄、较高的基线肌酐（>2.0）和/或较低的eGFR（<35）可预测ESRD。一般来说，停用RAAS阻滞剂后eGFR会改善。此外，在部分患者中，肾PTA和支架置入导致eGFR进一步改善。我们的观察结果需要进一步研究。
