Magid Fahim

BackgroundHemodialysis arteriovenous fistulas (AVFs) are suboptimally used primarily due to problems with maturation, early thrombosis, and patient nonacceptance. An endovascular approach to fistula creation without open surgery offers another hemodialysis vascular access option.Study DesignProspective, single-arm, multicenter study (Novel Endovascular Access Trial [NEAT]).Settings & ParticipantsConsecutive adult non−dialysis-dependent and dialysis-dependent patients referred for vascular access creation at 9 centers in Canada, Australia, and New Zealand.InterventionUsing catheter-based endovascular technology and radiofrequency energy, an anastomosis was created between target vessels, resulting in an endovascular AVF (endoAVF).OutcomesSafety, efficacy, functional usability, and patency end points.MeasurementsSafety as percentage of device-related serious adverse events; efficacy as percentage of endoAVFs physiologically suitable (brachial artery flow ≥ 500 mL/min, vein diameter ≥ 4 mm) for dialysis within 3 months; functional usability of endoAVFs to provide prescribed dialysis via 2-needle cannulation; primary and cumulative endoAVF patencies per standardized definitions.Results80 patients were enrolled (20 roll-in and 60 participants in the full analysis set; the latter are reported). EndoAVFs were created in 98% of participants; 8% had a serious procedure-related adverse event (2% device related). 87% were physiologically suitable for dialysis (eg, mean brachial artery flow, 918 mL/min; endoAVF vein diameter, 5.2 mm [cephalic vein]). EndoAVF functional usability was 64% in participants who received dialysis. 12-month primary and cumulative patencies were 69% and 84%, respectively.LimitationsDue to the unique anatomy and vessels used to create endoAVFs, this was a single-arm study without a surgical comparator.ConclusionsAn endoAVF can be reliably created using a radiofrequency magnetic catheter-based system, without open surgery and with minimal complications. The endoAVF can be successfully used for hemodialysis and demonstrated high 12-month cumulative patencies. It may be a viable alternative option for achieving AVFs for hemodialysis patients in need of vascular access. Hemodialysis arteriovenous fistulas (AVFs) are suboptimally used primarily due to problems with maturation, early thrombosis, and patient nonacceptance. An endovascular approach to fistula creation without open surgery offers another hemodialysis vascular access option. Prospective, single-arm, multicenter study (Novel Endovascular Access Trial [NEAT]). Consecutive adult non−dialysis-dependent and dialysis-dependent patients referred for vascular access creation at 9 centers in Canada, Australia, and New Zealand. Using catheter-based endovascular technology and radiofrequency energy, an anastomosis was created between target vessels, resulting in an endovascular AVF (endoAVF). Safety, efficacy, functional usability, and patency end points. Safety as percentage of device-related serious adverse events; efficacy as percentage of endoAVFs physiologically suitable (brachial artery flow ≥ 500 mL/min, vein diameter ≥ 4 mm) for dialysis within 3 months; functional usability of endoAVFs to provide prescribed dialysis via 2-needle cannulation; primary and cumulative endoAVF patencies per standardized definitions. 80 patients were enrolled (20 roll-in and 60 participants in the full analysis set; the latter are reported). EndoAVFs were created in 98% of participants; 8% had a serious procedure-related adverse event (2% device related). 87% were physiologically suitable for dialysis (eg, mean brachial artery flow, 918 mL/min; endoAVF vein diameter, 5.2 mm [cephalic vein]). EndoAVF functional usability was 64% in participants who received dialysis. 12-month primary and cumulative patencies were 69% and 84%, respectively. Due to the unique anatomy and vessels used to create endoAVFs, this was a single-arm study without a surgical comparator. An endoAVF can be reliably created using a radiofrequency magnetic catheter-based system, without open surgery and with minimal complications. The endoAVF can be successfully used for hemodialysis and demonstrated high 12-month cumulative patencies. It may be a viable alternative option for achieving AVFs for hemodialysis patients in need of vascular access.

BACKGROUND: Patients with chronic kidney disease (CKD) are at increased risk of coronary artery disease (CAD) and adverse cardiac events. Screening for CAD is therefore an important part of preoperative evaluation for kidney transplant candidates. There is significant interest in the role of non-invasive cardiac investigations and their ability to identify patients at high risk of CAD. OBJECTIVES: We investigated the accuracy of non-invasive cardiac screening tests compared with coronary angiography to detect CAD in patients who are potential kidney transplant recipients. SEARCH METHODS: MEDLINE and EMBASE searches (inception to November 2010) were performed to identify studies that assessed the diagnostic accuracy of non-invasive screening tests, using coronary angiography as the reference standard. We also conducted citation tracking via Web of Science and handsearched reference lists of identified primary studies and review articles. SELECTION CRITERIA: We included in this review all diagnostic cross sectional, cohort and randomised studies of test accuracy that compared the results of any cardiac test with coronary angiography (the reference standard) relating to patients considered as potential candidates for kidney transplantation or kidney-pancreas transplantation at the time diagnostic tests were performed. DATA COLLECTION AND ANALYSIS: We used a hierarchical modelling strategy to produce summary receiver operating characteristic (SROC) curves, and pooled estimates of sensitivity and specificity. Sensitivity analyses to determine test accuracy were performed if only studies that had full verification or applied a threshold of ≥ 70% stenosis on coronary angiography for the diagnosis of significant CAD were included. MAIN RESULTS: The following screening investigations included in the meta-analysis were: dobutamine stress echocardiography (DSE) (13 studies), myocardial perfusion scintigraphy (MPS) (nine studies), echocardiography (three studies), exercise stress electrocardiography (two studies), resting electrocardiography (three studies), and one study each of electron beam computed tomography (EBCT), exercise ventriculography, carotid intimal media thickness (CIMT) and digital subtraction fluorography (DSF). Sufficient studies were present to allow hierarchical summary receiver operating characteristic (HSROC) analysis for DSE and MPS. When including all available studies, both DSE and MPS had moderate sensitivity and specificity in detecting coronary artery stenosis in patients who are kidney transplant candidates [DSE (13 studies) - pooled sensitivity 0.79 (95% CI 0.67 to 0.88), pooled specificity 0.89 (95% CI 0.81 to 0.94); MPS (nine studies) - pooled sensitivity 0.74 (95% CI 0.54 to 0.87), pooled specificity 0.70 (95% CI 0.51 to 0.84)]. When limiting to studies which defined coronary artery stenosis using a reference threshold of ≥ 70% stenosis on coronary angiography, there was little change in these pooled estimates of accuracy [DSE (9 studies) - pooled sensitivity 0.76 (95% CI 0.60 to 0.87), specificity 0.88 (95% CI 0.78 to 0.94); MPS (7 studies) - pooled sensitivity 0.67 (95% CI 0.48 to 0.82), pooled specificity 0.77 (95% CI 0.61 to 0.88)]. There was evidence that DSE had improved accuracy over MPS (P = 0.02) when all studies were included in the analysis, but this was not significant when we excluded studies which did not avoid partial verification or use a reference standard threshold of ≥70% stenosis (P = 0.09). AUTHORS' CONCLUSIONS: DSE may perform better than MPS but additional studies directly comparing these cardiac screening tests are needed. Absence of significant CAD may not necessarily correlate with cardiac-event free survival following transplantation. Further research should focus on assessing the ability of functional tests to predict postoperative outcome.