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levels of CTGF and TGF-␤ will induce recruitment of myofibroblasts and provoke adventitial reorganization to limit outward remodeling of the vein graft in response to increased intramural wall stress.The authors created a model using a distal arterial venous fistula in the neck of rabbits that results in circumferential wall shear stress. Neck and fistula veins were harvested at 1, 3, and 7 days after implantation. Flow rates were recorded at the time of graft implantation and harvest using an ultrasonic flow meter. Real-time polymerase chain reaction and enzymelinked immunosorbent assays were used to assess production of CTGF and TGF-␤ 1 .With this model, the authors demonstrated increased production of TGF-␤ and CTGF in response to elevated wall stress. TGF-␤ and CTGF increased expression correlated with enhanced differentiation from fibroblasts to myofibroblasts, as reflected in increases in the ␣-actin-positive cells in the adventitia. Levels of ␣-actin, TGF-␤, and CTGF were all inversely correlated with outward remodeling of the graft wall.Comment: Wolinsky and Glagov originally demonstrated arterial adaption to maintain lumen diameter in atherosclerotic arteries. In vein grafts, this adaptive response might be limited by TGF-␤ and CTGF increases in myofibroblasts. Such an adaption may maintain vein wall integrity in the face of increased intraluminal pressure but may ultimately prove disadvantageous because it may limit the ability of the vein graft to maintain luminal diameter in response to the development of intimal hyperplasia. Temporary worsening of renal function after aortic surgery is associated with higher long-term mortalityWelten GM, Schouten O, Chonchol M, et al. Am J Kidney Dis 2007;50: 219-28. Conclusion: Temporary worsening of renal function after open surgery for abdominal aortic aneurysm (AAA) is associated with an increased long-term mortality rate.Summary: The authors sought to determine the effects of temporary renal dysfunction on the long-term mortality rate in patients undergoing AAA surgery. From January 1995 to June 2006, 1324 patients underwent elective open AAA repair in a single center in Rotterdam. Creatinine clearance was measured preoperatively and on postoperative days 1, 2, and 3. The patients were then divided into three groups. Group 1 had improved or unchanged renal function. Group 2 had temporary worsening of renal function with a Ͼ10% decrease on day 1 or 2, and then recovery Յ10% of baseline by day 3. Group 3 patients had persistent worsening of renal function as defined by a Ͼ10% decrease in creatinine clearance compared with the baseline value.The 30-day mortality rates in groups 1, 2, and 3 were 1.2%, 5%, and 12.6%, respectively. Adjusting for postoperative complications and baseline characteristics, the 30-day mortality rate was greatest in the patients with persistent worsening of renal function (hazard ratio (HR), 7.3; 95% confidence interval [CI], 2.7-19.8). Those who had temporary worsening of renal function also had an increased mortality risk (HR, 3.7; 95% CI...

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