Duplex ultrasound evaluation of hemodialysis access: a detailed protocol.
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ABSTRACT:
SUBMITTER: Teodorescu V
PROVIDER: S-EPMC3400354 | biostudies-literature | 2012
REPOSITORIES: biostudies-literature
Publications
Duplex ultrasound evaluation of hemodialysis access: a detailed protocol.
Teodorescu Victoria V Gustavson Susan S Schanzer Harry H
International journal of nephrology 20120710
A detailed protocol for the performance and interpretation of duplex ultrasound evaluation of hemodialysis access is described. ...[more]
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Project description:OBJECTIVE:Arteriovenous fistula (AVF) creation is the preferred approach for hemodialysis access; however, the maturation of AVFs is known to be poor. We established a proactive early duplex ultrasound (DUS) surveillance protocol for evaluating AVFs before attempted access. This study determined the effect of this protocol related to improving AVF maturation. METHODS:From 2008 to 2013, 153 patients received new upper extremity AVFs and an early DUS surveillance protocol at a single academic institution. The protocol involved an early DUS evaluation before hemodialysis cannulation of the AVF at 4 to 8 weeks after AVF creation. A positive DUS result was identified as a peak systolic velocity of >375 cm/s or a >50% stenosis on gray scale imaging, along with decreased velocity in the outflow vein. Patients with positive DUS findings underwent prophylactic endovascular or open intervention to assist with AVF maturation. Nature of secondary interventions, as well as AVF patency and maturation, were assessed. Overall clinical outcomes and fistula patency were investigated. RESULTS:During the study period, 183 upper extremity AVFs were created in 153 patients, including 82 radiocephalic, 63 brachiocephalic, and 38 brachiobasilic AVFs. A mortality rate of 43% (n = 66) was observed in a median follow-up period of 34.5 months (interquartile range, 19.6-46.9). A total of 164 early DUS were performed at a median of 6 weeks (interquartile range, 3.4-9.6 weeks) after the initial creation. Early DUS showed nine AVFs were occluded and were excluded from further analysis. Hemodynamically significant lesions were found in 62 AVFs (40%); however, only 17 (11%) were associated with an abnormal physical examination. Positive DUS finding prompted a secondary intervention in 81% of the patients. Among those with positive early DUS findings, AVF maturation was 70% in those undergoing a secondary intervention compared with 25% in those not undergoing a prophylactic intervention (P = .011). Primary-assisted patency for AVFs with early positive and negative DUS findings were 83% and 96% at 6 months, 64% and 89% at 1 year, and 52% and 82% at 2 years, respectively (P < .001). CONCLUSIONS:Early DUS surveillance of AVFs before initial access is reasonable to identify problematic AVFs that may not be reliably detected on clinical examination. Although DUS criteria for AVFs have yet to be universally accepted, proactive early postoperative DUS interrogation assists in the early detection of dysfunctional AVFs and improvement of fistula maturation. Despite improved patency in those with positive DUS findings who undergo prophylactic secondary intervention, overall patency remains inferior to those without an abnormality detected on early DUS imaging.
| S-EPMC6706077 | biostudies-literature
Project description:The rise in prevalence of end stage renal disease (ESRD) and the impact on health care resulted in increasing focus on delivery of vascular access. Hemodialysis vascular access is the most common renal replacement therapy method. The vascular access types include arteriovenous fistula, arteriovenous graft, and tunneled central venous catheters. Vascular access function remains an important outcome measure with significant impact on morbidity and health care cost. The survival and quality of life of patients on hemodialysis is dependent on the adequacy of dialysis through proper vascular access. Early detection of failure to mature vascular access, stenosis, thrombosis, and aneurysm or pseudoaneurysm formation remains crucial. Ultrasound can help identify complications, even though ultrasound evaluation of the arteriovenous access is less well defined. Some published vascular access guidelines support ultrasound for detecting stenosis. The evolution of ultrasound has improved throughout the years, both multi parametric top-line systems and hand-held systems. Ultrasound evaluation is inexpensive, rapid, noninvasive, and repeatable, it is a powerful tool used for early diagnosis. The ultrasound image quality still depends on the skill of the operator. Careful attention to technical details is needed and avoidance of several diagnostic pitfalls is necessary. This review is focused on the role of ultrasound for hemodialysis access surveillance, evaluation of maturation, detection of access complications, and aid with cannulation.
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Project description:Objectives This study clarified the usefulness of carotid duplex ultrasound (CDU) in evaluating large vessel occlusion (LVO) in patients with acute stroke planned to be treated with mechanical thrombectomy (MT). Methods This study was single-center, prospective, observational trial. If the ratio of end-diastolic velocity in the common carotid arteries was ≥1.4, or diastolic flow in the affected internal carotid artery (ICA) was absent on CDU, patients were immediately transferred to the angio-suite without additional cerebrovascular imaging. Clinical parameters, including time metrics and outcomes, were evaluated in participants. Patients We enrolled stroke patients with a National Institutes of Health Stroke Scale score ≥6 and Alberta Stroke Program Early CT score ≥6 in whom MT could be initiated within 6 hours of the stroke onset. Results Among 140 patients screened during the study period, 48 were ultimately enrolled. Twenty-seven patients were diagnosed with LVO by CDU alone. CDU offered 83% sensitivity and 82% specificity for identifying the occlusion of the ICA or M1 segment of the middle cerebral artery. Among the 29 total patients treated with MT, 20 (67%) showed a modified Rankin Scale score ≤2 at 90 days. The door-to-puncture time was significantly shorter in patients evaluated by CDU alone (34 minutes) than in those evaluated by magnetic resonance angiography after CDU (47.5 minutes, p<0.001). Conclusion CDU might reduce the time metrics for early initiation of MT with good sensitivity and specificity in identifying LVO.
| S-EPMC10037017 | biostudies-literature
Project description:IntroductionArteriovenous (AV) access thrombosis remains 1 of the most troubling AV access-related complications affecting hemodialysis patients. It necessitates an urgent and occasionally complicated thrombectomy procedure and increases the risk of AV access loss. AV access stenosis is found in the majority of thrombosed AV accesses. The routine use of AV access surveillance for the early detection and management of stenosis to reduce the thrombosis rate remains controversial.MethodsWe have conducted a multicenter, prospective, randomized clinical trial comparing the standard of care coupled with ultrasound dilution technique (UDT) flow measurement monthly surveillance with the standard of care alone.ResultsWe prospectively randomized 436 patients with end-stage renal disease on hemodialysis with arteriovenous fistula (AVF) or arteriovenous graft (AVG) using cluster (shift) randomization to surveillance and control groups. There were no significant differences in the baseline demographic data between the 2 groups, except for ethnicity (P = 0.017). Patients were followed on average for 15.2 months. There were significantly less per-patient thrombotic events (Poisson rate) in the surveillance group (0.12/patient) compared with the control group (0.23/patient) (P = 0.012). There was no statistically significant difference in the total number of procedures between the 2 groups, irrespective of whether thrombectomy procedures were included or excluded, and no statistically significant differences in the rate of or time to the first thrombotic event or the number of catheters placed due to thrombosis.ConclusionThe use of UDT flow measurement monthly AV access surveillance in this multicenter randomized controlled trial reduced the per-patient thrombotic events without significantly increasing the total number of angiographic procedures. Even though there is a trend, surveillance did not reduce the first thrombotic event rate.
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Project description:To evaluate the feasibility and potential on therapy management of time-resolved dynamic computed tomography angiography (dCTA) in patients with forearm arterio-venous fistula (AVF)/arterio-venous grafts (AVG). Thirty-five patients with complex failing forearm AVF/AVGs were examined with ultrasound and a dCTA protocol. Diagnosis and therapy management was evaluated versus duplex ultrasound (DUS) in three different readouts: 1. all dCTA datasets; 2. one arterial phase of the dCTA dataset; 3. one arterial and one venous dataset out of the dCTA dataset. All reads were performed >30 days apart from each other. Using all data of the dCTA examination, 20 patients were classified as having a stenosis >50%, 12 high-shunt flow, 11 partial thrombosis, 5 venous aneurysms and 5 complete thrombosis of their AVF/AVG grafts. This lead to 13 additional pathologic findings not visible on DUS and reclassification as normal in one patient with suspected AVF stenosis and complete thrombus on DUS. These additional findings lead to a direct change of therapeutic management in 8 patients. Compared to readout 1 (53 pathologies), readout number 2 and 3 revealed only 33 and 41 pathologies, respectively. dCTA provides additional information, improving diagnostic confidence and leading to changes in therapy management when compared to DUS alone.
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Project description: Not available
| S-EPMC8039423 | biostudies-literature
Project description:Most arteriovenous grafts fail due to irreversible thrombosis, and most clotted grafts have an underlying stenotic lesion. These observations raise the plausible hypothesis that early detection of graft stenosis with preemptive angioplasty will reduce the likelihood of graft thrombosis. A number of noninvasive methods can be used to detect hemodynamically significant graft stenosis with a high positive predictive value. These tests include clinical monitoring, as well as surveillance by static dialysis venous pressures, flow monitoring, or duplex ultrasound. However, these surveillance tests have a much lower positive predictive value for graft thrombosis in the absence of preemptive angioplasty. In other words, none of the currently available surveillance tests can reliably distinguish between stenosed grafts destined to clot, and those that will remain patent without intervention. As a consequence, any program of graft surveillance necessarily results in a substantial proportion of unnecessary angioplasties. Moreover, a substantial proportion of grafts thrombose despite a normal antecedent surveillance test. Numerous observational studies have found an impressive reduction of graft thrombosis after implementation of a stenosis surveillance program. In contrast, 5 of 6 randomized clinical trials failed to show a reduction of graft thrombosis in patients undergoing graft surveillance, as compared with those receiving only clinical monitoring. The lack of benefit of surveillance is largely attributable to the rapid recurrence of stenosis after angioplasty. Thus, routine surveillance for graft stenosis, with preemptive angioplasty, cannot be recommended for reduction of graft thrombosis. Future research should be directed at pharmacologic interventions to prevent graft stenosis.
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Project description:IntroductionThe anatomy and physiology of the temporomandibular joint can be studied clinically and by diagnostic imaging. Magnetic resonance imaging (MRI), radiography (X-ray) and computed tomography (CT) have thus for many years contributed to the study of the kinetics in the mandibular condyle. However, also duplex Doppler ultrasound (US) examination is widely used in the study of structures during movement, particularly vascular structures.Materials and methodsA total of 30 patients were referred by the Department of Orthodontics to the Department of Radiological, Oncological and Pathological Sciences, University of Rome "La Sapienza". All patients underwent duplex Doppler ultrasound (US) examination of the temporomandibular joint using Toshiba APLIO SSA-770A equipment and duplex Doppler multi-display technique, which allows simultaneous display of US images and color Doppler signals. A linear phased array probe with crystal elements was used operating at a basic frequency of 6 MHz during pulsed Doppler spectral analysis and 7.5 MHz during US imaging.ResultsIn normal patients a regular alternation in the spectral Doppler waveforms was obtained, while in patients with temporomandibular joint meniscus dysfunction there was no regularity in the sum of the Fourier series with an unsteady waveform pattern related to irregular movements of the temporomandibular joint.ConclusionsIn all cases duplex Doppler US examination proved able to differentiate between normal and pathological patients and among the latter this technique permitted identification of the most significant aspects of the dysfunctional diseases.
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