Mohamed Zayed

Stanford Medicine, Stanford, California, United States

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Publications (5)11.54 Total impact

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    ABSTRACT: OBJECTIVE: Rates of inferior vena cava (IVC) filter retrieval have remained suboptimal, in part because of poor follow-up. The goal of our study was to determine demographic and clinical factors predictive of IVC filter follow-up care in a university hospital setting. METHODS: We reviewed 250 consecutive patients who received an IVC filter placement with the intention of subsequent retrieval between March 2009 and October 2010. Patient demographics, clinical factors, and physician specialty were evaluated. Multivariate logistic regression analysis was performed to identify variables predicting follow-up care. RESULTS: In our cohort, 60.7% of patients received follow-up care; of those, 93% had IVC filter retrieval. Major indications for IVC filter placement were prophylaxis for high risk surgery (53%) and venous thromboembolic event with contraindication and/or failure of anticoagulation (39%). Follow-up care was less likely for patients discharged to acute rehabilitation or skilled nursing facilities (P < .0001), those with central nervous system pathology (eg, cerebral hemorrhage or spinal fracture; P < .0001), and for those who did not receive an IVC filter placement by a vascular surgeon (P < .0001). In a multivariate analysis, discharge home (odds ratio [OR], 4.0; 95% confidence interval [CI], 1.99-8.2; P < .0001), central nervous system pathology (OR, 0.46; 95% CI, 0.22-0.95; P = .04), and IVC filter placement by the vascular surgery service (OR, 4.7; 95% CI, 2.3-9.6; P < .0001) remained independent predictors of follow-up care. Trauma status and distance of residence did not significantly impact likelihood of patient follow-up. CONCLUSIONS: Service-dependent practice paradigms play a critical role in patient follow-up and IVC filter retrieval rates. Nevertheless, specific patient populations are more prone to having poorer rates of follow-up. Such trends should be factored into institutional quality control goals and patient-centered care.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 04/2013; · 3.52 Impact Factor
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    ABSTRACT: The National Kidney Foundation recommends that arteriovenous fistulas (AVFs) be placed in at least 65% of hemodialysis patients. Some studies suggest that African American patients are less likely to receive a first-time AVF than patients of other ethnicities, although the reason for this disparity is unclear. The purpose of our study is to determine (1) whether there are ethnic differences in AVF creation, (2) whether this may be related to differences in vein diameters, and (3) whether AVF patency rates are similar between African American and non-African American male patients. Consecutive male patients undergoing first-time hemodialysis access from 2006 to 2010 at two institutions were retrospectively reviewed. Data collected included age, ethnicity, weight, height, body mass index, diabetes, hypertension, congestive heart failure, smoking history, intravenous drug abuse, need for temporary access placement, and preoperative venous ultrasound measurements. Categoric variables were compared using χ(2) analysis, and the Wilcoxon rank-sum test was used to compare continuous variables. Of 249 male patients identified, 95 were African American. Median age in African American and non-African American patients was 63 years. Hypertension and hyperlipidemia were statistically significantly greater in African American patients. The need for temporary access before hemoaccess was similar between the cohorts. African American patients demonstrated significantly smaller median basilic and cephalic vein diameters at most measured sites. Overall, 221 of 249 (88.8%) underwent AVF first. An AV graft was created in 17.9% of African American patients vs in only 7.1% of non-African Americans (odds ratio, 2.8; 95% confidence interval, 1.3-6.4; P = .009). The difference between median vein diameters used for autologous fistula creation in African American and non-African American patients was not significant. There was no significant difference in the primary patency (80.8% vs 76.2%; P = .4), primary functional patency (73.1% vs 69.2%; P = .5), or secondary functional patency rates (91.0% vs 96.5%; P = .1). Average primary fistula survival time was 257 days in African American and 256 in non-African American patients (P = .2). African American patients are less likely than non-African American patients to undergo AVF during first-time hemodialysis access surgery. This ethnic discrepancy appears to be due to smaller arm vein diameters in African American patients. In African American patients with appropriate vein diameters who do undergo AVF, primary and functional patencies are equivalent to non-African American patients.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 04/2012; 56(2):424-31; discussion 431-2. · 3.52 Impact Factor
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    ABSTRACT: Loeys-Dietz syndrome (LDS) is a rare congenital connective tissue disorder (CTD) caused by mutations in the gene encoding for transforming growth factor-β receptors I and II. This recently described syndrome is characterized by aortic aneurysms and dissections, arterial tortuosity, and spontaneous organ perforation. The technical feasibility of endovascular interventions, particularly endovascular aneurysm repair (EVAR), in CTDs is relatively unknown. A 38-year-old man presented with asymptomatic bilateral common iliac artery aneurysms measuring 5.3 cm on the right and 4.3 cm on the left. The patient had an extensive surgical and medical history, including a recently repaired Stanford type-A aortic dissection, total colectomy with end ileostomy for a colonic perforation, splenectomy for rupture, and cirrhosis secondary to chronic hepatitis C. The patient's CTD, multiple abdominal surgeries performed in the past, and ileostomy made him a poor candidate for open repair. We elected to offer him a complex endovascular repair and hoped to preserve his pelvic circulation by using "double-barrel" configuration of stent-grafts in the right iliac artery system. Successful deployment of the devices and repair of femoral access allowed routine discharge on postoperative day 2. At 6-month follow-up, the patient's pelvic circulation has been maintained, the aneurysms are excluded without endoleak, and sac regression has been shown. LDS is a rare connective tissue disorder characterized by vascular aneurysms and arterial tortuosity. When vascular reconstruction is necessary, open techniques are often preferred given the lack of data on endovascular procedures. In the present case, we report the first successful abdominal EVAR in a high-risk patient with LDS, providing excellent short-term results.
    Annals of Vascular Surgery 08/2011; 26(1):107.e5-10. · 0.99 Impact Factor
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    ABSTRACT: Brachiobasilic arteriovenous fistulas (BBAVF) can be performed in one or two stages. We compared primary failure rates, as well as primary and secondary patency rates of one- and two-stage BBAVF at two institutions. Patients undergoing one- and two-stage BBAVF at two institutions were compared retrospectively with respect to age, sex, body mass index, use of preoperative venous duplex ultrasound, diabetes, hypertension, and cause of end-stage renal disease. Categorical variables were compared using chi-square and Fisher's exact test, whereas the Wilcoxon rank-sum test was used to compare continuous variables. Patency rates were assessed using the Kaplan-Meier survival analysis and the Cox proportional hazards model with propensity analysis to determine hazard ratios. Ninety patients (60 one-stage and 30 two-stage) were identified. Mean follow-up was 14.2 months and the mean time interval between the first and second stage was 11.2 weeks. Although no significant difference in early failure existed (one-stage, 22.9% vs two-stage, 9.1%; P = .20), the two-stage BBAVF showed significantly improved primary functional patency at 1 year at 88% vs 61% (P = .047) (hazard ratio, 0.2 (95% confidence interval [CI], .04-.80; P = .03). Patency for one-stage BBAVF markedly decreased to 34% at 2 years compared with 88% for the two-stage procedure (P = .047). Median primary functional patency for one-stage BBAVF was 31 weeks (interquartile range [IQR], 11-54) vs 79 weeks (IQR, 29-131 weeks) for the two-stage procedure, respectively (P = .0015). Two-year secondary functional patency for one- and two-stage procedures were 41% and 94%, respectively (P = .015). Primary and secondary patency at 1 and 2 years as well as functional patency is improved with the two-stage BBAVF when compared with the one-stage procedure. Lower primary failure rates prior to dialysis with the two-stage procedure approached, but did not reach statistical significance. While reasons for these finding are unclear, certain technical aspects of the procedure may play a role.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 06/2011; 53(6):1632-8; discussion 1639. · 3.52 Impact Factor
  • Source
    Journal of Vascular Surgery. 08/2010; 52(2):527.