Increased risk of renal dysfunction with percutaneous mechanical thrombectomy compared with catheter-directed thrombolysis.

OBJECTIVE: Percutaneous mechanical thrombectomy (PMT) is regularly used in the treatment of both venous and arterial thrombosis. Although there has been no formal report, PMT has been linked to cases of reversible postoperative acute kidney injury (AKI). The purpose of this study is to evaluate the risk of renal dysfunction in patients undergoing PMT vs catheter-directed thrombolysis (CDT) for treatment of an acute thrombus. METHODS: This study is a retrospective review of all patients in a single institution with a Current Procedural Terminology code for PMT or CDT from January 2009 through December 2014. Each patient was grouped into one of the four following procedural categories: PMT only, PMT with tissue plasminogen activator (tPA) pulse-spray, PMT with CDT, or CDT only. Preoperative and postoperative creatinine and glomerular filtration rate (GFR) values were obtained for each patient. The RIFLE (Risk, Injury, Failure, Loss, and End-stage renal disease) criteria were used to categorize the extent of renal dysfunction. χ2 analysis, one-way analysis of variance, and unpaired t-test were used to assess significance. RESULTS: A total of 227 patients were reviewed, of which 82 were excluded due to either existence of preoperative AKI, history of end-stage renal disease, or lack of clinical data. Of the remaining 145 patients, 53 (37%) presented with arterial thrombosis (mean age, 62 years; 43% male) and 92 (63%) presented with venous thrombosis (mean age, 48 years; 45% male). The incidence of renal dysfunction was highest in the PMT/tPA pulse group (21%), followed by the PMT group (20%) and the PMT/CDT group (14%). CDT was not associated with renal dysfunction. PMT (P = .046), and PMT/tPA pulse (P = .033) were associated with higher rates of renal dysfunction than the CDT controls. The average preoperative GFR for the 22 patients who developed AKI was 53.7 ± 9.4 mL/min/1.73 m2. The minimum postoperative GFR within 48 hours was an average of 35 ± 16 mL/min/1.73 m2. Stratified by the RIFLE criteria, 13 (9%) patients progressed to the risk category, 6 (4%) progressed to the injury category, and 3 (2%) progressed to the failure category. None of the patients who developed renal dysfunction from PMT progressed to dialysis within the same admission period. CONCLUSIONS: The use of PMT as a treatment for vascular thrombosis is associated with renal dysfunction. Patients treated with PMT require postoperative vigilance and renal protective measures.

Elevated Peak Systolic Velocity and Velocity Ratio from Duplex Ultrasound are Associated with Hemodynamically Significant Lesions in Arteriovenous Access.

BACKGROUND: Duplex ultrasound (DUS) is reliably used to detect lesions in the peripheral and carotid arterial beds and venous system. Although commonly used in clinical practice, duplex criteria to define lesions in arteriovenous access are not well characterized. This study will define the optimal Doppler-derived peak systolic velocity (PSV) and velocity ratio (VR) to identify >50% lesions in arteriovenous fistulas (AVF) and arteriovenous grafts (AVG). METHODS: This retrospective analysis includes patients with both DUS and fistulogram within 30 days. DUS-derived PSV and VR were recorded for 3 segments of each access and compared with fistulograms of the same 3 segments of each AV access. Receiver operating characteristic (ROC) was used to determine the optimal DUS criteria for diagnosis of >50% stenosis. RESULTS: Fifty pairs of imaging in 40 patients were available for analysis. Mean PSV and VR for segments with greater than 50% stenosis were significantly greater than those without; mean PSV of 480 cm/sec vs. 297 cm/sec (P < 0.001) and mean VR of 3.81 vs. 2.09 (P < 0.001). The ROC analysis demonstrated an optimal PSV of 404 and VR of 2.2 to diagnose >50% stenosis with area under the curve of 0.825 and 0.821 for PSV and VR, respectively. PSV of 500 had sensitivity (Se) of 0.60, specificity (Sp) of 0.86, positive predictive value (PPV) of 0.72, and negative predictive value (NPV) of 0.78. VR of 3.0 had Se of 0.52, Sp of 0.91, PPV of 0.77, and NPV of 0.75. CONCLUSIONS: DUS-derived PSV of 400 cm/sec and VR of 2.25 have good discrimination to predict greater than 50% stenosis in AVFs and AVGs. Given the broad range of velocities in AV accesses, a threshold of PSV greater than 500 cm/sec and VR greater than 3.0, will reliably identify graft-threatening lesions. Se and Sp of PSV 500 are 0.596 and 0.854, respectively. Se and Sp for VR 3.0 are 0.519 and 0.894, respectively.