Date of Award

9-11-2009

Document Type

Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Dr. John Concato

Second Advisor

Dr. Aldo Peixoto

Third Advisor

Dr. Peter Aronson

Abstract

The impact of percutaneous renal artery angioplasty and stenting (PTRAS) for treatment of atherosclerotic renal artery stenosis (ARAS) is not fully understood, especially in patients with chronic kidney disease (CKD). We performed a retrospective cohort study of patients with significant ARAS and moderate to severe chronic kidney disease (estimated GFR 15-60 ml/min/1.73m2) who were treated medically or with PTRAS. The primary endpoint of this study was change in renal function over the first year after treatment. Secondary endpoints included hemodynamic outcomes, antihypertensive medication doses, end stage renal disease (ESRD), and death. We reviewed all patients with a diagnosis of significant ARAS and impaired GFR treated between 1997-2007 in the Veterans Affairs Connecticut Healthcare System (VACHS). A total of 118 patients met inclusion criteria (71 medical treatment, 47 PTRAS), with an average follow-up of 34 months. The students t-test was used to compare baseline characteristics, as well as renal and hemodynamic endpoints between the two treatment groups. The cohort had a mean age of 73 ± 9 years and average baseline GFR of 37.2 ± 14.9 ml/min/1.73m2. Demographic, clinical and laboratory characteristics at baseline were similar between the two groups, with the exception of higher diastolic blood pressure in the stent group at baseline (75 versus 70 mmHg, p=0.028). No statistically significant difference was found between the two treatment groups for any renal endpoints. After a steady decline in GFR in both the medical treatment and stent groups during the 12 months preceding diagnosis (-4.2 versus -4.0 ml/min/1.73m2, p=0.911), GFR stabilized in both groups over the year following diagnosis (decline in GFR of -1.6 versus -1.4 ml/min/1.73m2, p=0.938). Multivariate models did not reveal an association between treatment modality and percent change in GFR during follow-up. No difference was found in blood pressure outcomes at 12 months between the medical and stent groups. Antihypertensive therapy, measured in defined daily doses (DDDs), was significantly higher in the medical treatment group at 12 months (4.5 versus 3.5 DDDs, p=0.048), but lost significance thereafter. In addition, the number of deaths was significantly higher in the stented group on univariate analysis, although this did not remain significant on multivariable Cox analysis. No difference was found between treatment groups in the development of ESRD. These data suggest that, among patients with ARAS and CKD, medical therapy and renal artery stenting are comparable in stabilizing renal function.

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