Endograft salvage of hemodialysis accesses threatened by pseudoaneurysms.

OBJECTIVE: Currently, no formal practice guidelines exist regarding the use of endografts to exclude hemodialysis access pseudoaneurysms and prolong access lifespan in dialysis patients. We evaluated the efficacy of percutaneous endograft placement for exclusion of hemodialysis access pseudoaneurysms. METHODS: Between July 2005 and October 2009, 32 patients were prospectively evaluated. Twenty-four patients were actively enrolled in the study based upon clinical and ultrasonographic evaluation of their hemodialysis accesses. Self-expanding covered endografts were placed percutaneously to exclude access pseudoaneurysms. Patients were evaluated at 2 and 6 months to assess for graft patency, access or outflow stenosis, endoleak, or stent graft migration. RESULTS: No procedural complications resulted from these interventions. An average of 1.8 endografts was placed per patient, with patients requiring between 1 and 3 endografts to exclude pseudoaneurysms. Primary-assisted patency was 83% at completed 2-month follow-up and 54% at 6-month follow-up. At 12 months, primary-assisted patency was 50%. Eleven patients left the study before 6-month follow-up: five (21%) required explantation secondary to infection between 1 and 4 months; three (13%) were lost to follow-up; two (8%) died of unrelated causes; and 1 requested explantation citing pain from the "stent poking the vein." Mean time to explantation secondary to infection was 2.4 months. Mean duration of patency was 17.6 months with a range from 0 to 76 months. Mean duration of patency for patients who completed 6-month follow-up was 28.7 months. The longest duration of patency is 6 years 4 months, after stent fracture and subsequent placement of a new stent at 6 years 2 months. One other incident of stent fracture occurred at 36 months. Dialysis patterns were not interrupted in either patient. CONCLUSIONS: The long-term results demonstrate that endograft salvage of failing hemodialysis accesses is a viable and safe alternative to open surgical revision that excludes pseudoaneurysms while maintaining uninterrupted access patency. A larger sample size and longer follow-up are needed to support the study data.

Effects of cilostazol on human venous smooth muscle.

In this study, we evaluated the effect of therapeutic doses of cilostazol on human venous smooth muscle. Saphenous vein rings (two to four per patient sample) were suspended in tissue baths for isometric tension recordings. At the beginning of the experiment, optimal tension for isometric contraction was achieved for each ring in a stepwise fashion in the presence of norepinephrine (10(-2) M). Norepinepherine was then added cumulatively in half-molar increments and isometric tension developed by the rings was measured, thereby obtaining a dose-response curve. Following washout and reequilibration, the rings were precontracted with a 30-50% submaximal dose of norepinepherine determined from the dose-response curve and allowed to contract until a stable plateau was reached. Cilostazol was then added in a cumulative manner (680-2,720 microg/L), and the tension generated was recorded. A total of 76 venous rings were tested, and all relaxed in the presence of cilostazol. The amount of relaxation increased as the concentration of cilostazol increased. Relaxation of 15 +/- 1.9% (mean +/- SEM) at low cilostazol doses (680 microg/L) to 37+/-3% at high cilostazol doses (2,720 microg/L) was demonstrated. A second finding of this study was demonstrated when the patient samples were divided according to the presence or absence of risk factors for arteriosclerosis. The specific risk factors examined included diabetes mellitus, smoking, hypercholesterolemia, and hypertension. The presence or absence of hypertension (n = 52) or hypercholesterolemia (n = 18) did not affect the amount of relaxation of the venous rings. Smokers (n = 46) had less relaxation 16 +/- 2.4% (680 microg/L) to 41 +/- 3.6% (2,720 microg/L) compared to nonsmokers (n = 53) who relaxed 22 +/- 3.5% (680 microg/L) to 48 +/- 5.7% (2720 microg/L). This did not reach statistical significance at any concentration cilostazol (p = 0.11-0.18). Diabetics (n = 53) did have statistically significantly less relaxation at every concentration of cilostazol compared to nondiabetics (n = 11, p < 0.05). All venous rings relaxed in the presence of cilostazol. Veins of nondiabetics relaxed statistically significantly more than those of diabetics. Smokers had less relaxation than non-smokers, but this was not statistically significant. We are the first to demonstrate that human venous smooth muscle cells undergo relaxation when exposed to therapeutic concentrations of cilostazol.

Takayasu's arteritis presenting as uveitis in a 5-year-old girl.

A 5-year-old patient presented with uveitis as initial manifestation of Takayasu's arteritis. Our patient is unique not only in the initial presentation but also in the extent of arteritis in the aortic arch and great vessels. This is only the second case reported in the literature with this unusual presentation.