Zhang, Xin

The significance of peristenotic collateral circulation (PCC) development around a stenotic renal artery is unknown. We tested the hypothesis that PCC is linked to loss of kidney function and recovery potential in patients with atherosclerotic renovascular disease (ARVD). Thirty-four patients with ARVD were assigned to medical-therapy with or without revascularization based on clinical indications. The PCC was visualized using multidetector computed tomography and defined relative to segmental arteries in patients with essential hypertension. PCC number before and 3 months after treatment was correlated with various renal parameters. Thirty-four stenotic kidneys from 30 patients were analyzed. PCC number correlated inversely with kidney volume. ARVD–stenotic kidneys with baseline PCC (collateral ARVD [C-ARVD], n=13) associated with elevated 24-hour urine protein and stenotic kidney vein level of tumor necrosis factor-α, lower single-kidney volume and blood flow, and greater hypoxia than in stenotic kidneys with no PCC (no collateral ARVD [NC-ARVD], n=17). Revascularization (but not medical-therapy alone) improved stenotic kidney function and reduced inflammation in both NC-ARVD and C-ARVD. In C-ARVD, revascularization also increased stenotic kidney volume, blood flow, and oxygenation to levels comparable to NC-ARVD, and induced PCC regression. However, revascularization improved systolic blood pressure, plasma renin activity, and filtration fraction only in NC-ARVD. Therefore, patients with C-ARVD have greater kidney dysfunction, atrophy, hypoxia, and inflammation compared with patients with NC-ARVD, suggesting that PCC does not effectively protect the stenotic kidney in ARVD. Renal artery revascularization improved in C-ARVD stenotic kidney function, but not hypertension or renin-angiotensin system activation. These observations may help direct management of patients with ARVD.

Abstract Background: Anemia is an extremely prevalent disease and contributes to a substantial percentage of worldwide years lived with disability. Clinicians generally agree that investigation of the gastrointestinal (GI) tract with colonoscopy and/or endoscopy is warranted in the presence of either overt clinical evidence of GI bleeding or in the presence of documented iron deficiency. However, little is known about the appropriateness of these procedures in the evaluation of patients without either overt GI bleeding or iron deficiency. Additionally, while a large number of colonoscopies and endoscopies are performed each year, the proportion of such procedures performed in the absence of suspect history or findings has not been characterized. Methods: We performed a retrospective review of all patients at Mayo Clinic Rochester who underwent endoscopy, colonoscopy, or both procedures between July 1, 2014 and June 30, 2015 for an indication of either "anemia" or "iron deficiency anemia." Sources of data included provider notes, laboratory values, procedure notes, and pathology reports. Information including patient demographic characteristics, medical comorbidities, laboratory values related to anemia, findings at the time of gastrointestinal procedure, and procedure-related complications was collected. Data was entered into an electronic database and data analysis was performed using Microsoft Excel. Results: 999 procedures were included, including 224 colonoscopies, 306 endoscopies, and 469 combined colonoscopy/endoscopies. Of the 999 total procedures, 78 (8%) had no documented pre-procedure hemoglobin value, 666 (67%) were performed after documented anemia (defined as hemoglobin ≤12 g/dL), and 255 (26%) were performed after a documented hemoglobin of >12 g/dL. Of the 675 procedures performed for "iron deficiency anemia," 462 (68%) patients had documented anemia and documented ferritin prior to the procedure, including only 237 (35%) with both hemoglobin ≤12 and ferritin ≤ 20. 388 (39%) had a documented pre-procedure patient and/or provider report of blood in the stool, and 111 (11%) had a documented pre-procedure positive hemoccult test. 365 (37%) of the 999 procedures identified a probable benign source of bleeding, 54 (5.4%) identified a probable malignant source, and 580 (58%) had no findings consistent with a bleeding source. Patients with documented anemia were more likely to have a probable bleeding source identified than those without documented anemia [46% versus 34%, p<.001]. Of the 83 patients with hemoglobin >12 and ferritin >20, only 1 procedure in 83 demonstrated a malignant finding, and this patient did have blood in the stool at the time of the procedure. There were 46 patients who underwent a procedure without any "warning signs" (either anemia and/or blood in the stool and/or positive hemoccult). Of these patients, 0 had a malignant finding. Conclusions: A large number of procedures performed for either "anemia" or "iron deficiency anemia" were done without pre-procedure documentation of anemia and/or iron deficiency. Documentation of anemia is associated with an increased chance of finding a source of bleeding during the procedure. There were no missed diagnoses of malignancy among patients undergoing procedures without anemia, blood in the stool, and/or positive hemoccult. Careful attention to documentation should be encouraged, and quality improvement initiatives requiring appropriate documentation prior to performing these procedures may be helpful. Disclosures No relevant conflicts of interest to declare.

Objective— Endothelial outgrowth cells (EOC) decrease inflammation and improve endothelial repair. Inflammation aggravates kidney injury in renal artery stenosis (RAS), and may account for its persistence upon revascularization. We hypothesized that EOC would decrease inflammatory (M1) macrophages and improve renal recovery in RAS. Approach and Results— Pigs with 10 weeks of RAS were studied 4 weeks after percutaneous transluminal renal angioplasty (PTRA+stenting) or sham, with or without adjunct intrarenal delivery of autologous EOC (10×10 6 ), and compared with similarly treated normal controls (n=7 each). Single-kidney function, microvascular and tissue remodeling, inflammation, oxidative stress, and fibrosis were evaluated. Four weeks after PTRA, EOC were engrafted in injected RAS-kidneys. Stenotic-kidney glomerular filtration rate was restored in RAS+EOC, RAS+PTRA, and RAS+PTRA+EOC pigs, whereas stenotic-kidney blood flow and angiogenesis were improved and fibrosis attenuated only in EOC-treated pigs. Furthermore, EOC increased cell proliferation and decreased the ratio of M1 (inflammatory)/M2 (reparative) macrophages, as well as circulating levels and stenotic-kidney release of inflammatory cytokines. Cultured-EOC released microvesicles in vitro and induced phenotypic switch (M1-to-M2) in cultured monocytes, which was inhibited by vascular endothelial growth factor blockade. Finally, a single intrarenal injection of rh-vascular endothelial growth factor (0.05 μg/kg) in 7 additional RAS pigs also restored M1/M2 ratio 4 weeks later. Conclusions— Intrarenal infusion of EOC after PTRA induced a vascular endothelial growth factor–mediated attenuation in macrophages inflammatory phenotype, preserved microvascular architecture and function, and decreased inflammation and fibrosis in the stenotic kidney, suggesting a novel mechanism and therapeutic potential for adjunctive EOC delivery in experimental RAS to improve PTRA outcomes.