Patency and Durability of Stent Grafts Placed in the Dialysis Circuit Cannulation Zone.

PURPOSE: To investigate the safety, durability, and patency rates of stent grafts (SGs) placed in the cannulation zone of hemodialysis access circuits. MATERIALS AND METHODS: From April 2020 to April 2023, all procedures with SGs placed in the cannulation zone were retrospectively analyzed. A total of 40 patients (25 men and 15 women) with SGs placed in the cannulation zone were included in the study. Mean age of the patients was 70 years. The Covera covered stent (BD, Franklin Lakes, New Jersey) was used in all cases. Of these, 26 were arteriovenous (AV) fistulae and 14 were AV grafts. SGs were placed for residual stenosis, perforation, aneurysm, and thrombosis. Follow-up outcomes were determined using follow-up angiographic images and included primary patency, primary-assisted patency, and secondary patency. RESULTS: The primary patency of the target lesion was 89% (SD ± 5) and 74% (SD ± 8.4) at 6 and 12 months, respectively. The primary-assisted patency was 89% (SD ± 5.2) and 78% (SD ± 7.6) at 6 and 12 months, respectively. Secondary patency of the access circuit was 97% (SD ± 2.5) at both 6 and 12 months. Mean follow-up was 332 days (range, 28-661 days). All SGs were successfully cannulated for hemodialysis. No cases of stent fracture or stent infection were observed during follow-up. CONCLUSIONS: SGs placed for cannulation zone pathologies can be safely cannulated for dialysis and have adequate short- and mid-term patency rates.

Complete stent graft relining of the hemodialysis access circuit for access salvage.

BACKGROUND: Stent grafts (SGs) are widely used in hemodialysis access procedures to maintain function and patency of the access circuit. There are no reports to date describing complete relining of the access circuit with SGs for extreme access salvage. OBJECTIVE: To report outcomes and experience with complete SG relining of the hemodialysis access circuit. METHODS: From April 2020 to May 2023, all hemodialysis salvage procedures that included complete relining of the access circuit with SGs were retrospectively analyzed from a prospectively collected database of 970 hemodialysis access interventions. SGs were placed for various pathologies including residual stenosis, perforation, aneurysm, and thrombosis. Follow up outcomes included primary patency, primary assisted patency, and secondary patency. RESULTS: A total of 16 patients were included in the study. Average stented length was 30 cm. Average follow up was 283 days (range 38-647 days). The primary patency of the entire covered segment was 80% and 68% at 6 and 12 months, respectively. The primary assisted patency of the segment was 88% and 77% at 6 and 12 months, respectively. Secondary patency of the access circuit was 94% at both 6 and 12 months. There were no issues with SG cannulation and zero cases of SG fracture or infection. CONCLUSIONS: Salvage of failing hemodialysis access circuits by complete SG relining should be considered for a limited subgroup of patients where the access circuit would otherwise be deemed unsalvageable. Complete SG relining has both good immediate outcomes and 6- and 12-month patency rates.

Stent Grafts Across the Elbow Joint for Access Salvage.

PURPOSE: Covered stent grafts (SGs) are currently being used in a wide variety of situations to maintain function and patency of hemodialysis access circuits. Stent grafts are rarely placed across the elbow joint (EJ), however, due to fear of stent fracture. This study reports on the experience and patency rates with SGs across the EJ. MATERIALS AND METHODS: From April 2020 to August 2023, all procedures with SGs placed across the EJ were retrospectively analyzed. A total of 21 patients with SGs placed across the EJ were included in the study. The Covera Vascular Covered Stent (BD, Franklin Lakes, New Jersey, USA) was used in all cases. Of these, 18 were arteriovenous (AV) fistulae, and 3 were AV grafts. Stent grafts were placed for various pathologies, including residual stenosis, perforation, aneurysm, and thrombosis. Follow-up outcomes were obtained from angiographic images on follow-up angiography and included primary patency, primary assisted patency, and secondary patency. RESULTS: The primary patency of the target lesion was 85% (CI=70%-100%) and 85% (CI=70%-100%) at 6 and 12 months, respectively. The primary assisted patency was 85% (CI=70%-100%) and 85% (CI=70%-100%) at 6 and 12 months, respectively. Secondary patency of the access circuit was 95% (CI=86%-100%) at 6 months and 89% (CI=75%-100%) at 12 months. The average follow-up duration was 393 days (range=27-768 days). There were no instances of stent fracture during follow-up. CONCLUSIONS: Stent grafts should be placed across the EJ for good short-term and mid-term patency rates. CLINICAL IMPACT: The placement of stent grafts across the elbow joint in hemodialysis patients for access salvage is controversial due to the fear of stent fracture or occlusion. This retrospective study evaluated the placement of stent grafts for access salvage in 21 patients for various etiologies. Good patency rates were seen out to 12 months and no stent fractures were observed. Although longer term data is needed, stent grafts should be considered an acceptable option for access salvage when treating lesions that cross the elbow joint.

Pave and Pop: A novel addition to the endovascular treatment of hemodialysis access aneurysms.

BACKGROUND: Hemodialysis access sites can be complicated by both true and false aneurysms with significant potential morbidity. Aneurysms have traditionally been treated by a variety of surgical methods. Less commonly, endovascular treatment with stent graft placement has been used as an alternative to open surgery. METHODS: Four patients with symptomatic aneurysmal disease in the hemodialysis access site were treated. All patients had stent grafts (SGs) placed across the diseased segment. Once the diseased segment was excluded, blood was drained from the aneurysm with an 18 g needle. All patients were seen in clinic at 1- and 3-months post procedure. RESULTS: All patients were able to receive adequate hemodialysis post procedure. Two patients were cannulated via the SG after 1 month. No aneurysm refilling was seen. No SG infections or fractures were seen. CONCLUSION: A novel addition to the endovascular treatment of aneurysmal disease in hemodialysis patients is described, that both excludes the aneurysm and drains it, providing improvement in the aesthetic appearance of the access site.

Early experience with the Abre venous stent for central venous stenoses and occlusions in hemodialysis patients.

BACKGROUND: Hemodialysis patients are prone to stenoses and occlusions throughout the access circuit. Central venous stenoses or occlusions (CVO) can be particularly challenging. There are many different types of balloons and stents available for treatment, including a new generation of dedicated venous stents (VS). In this study, we report our experience and patency rates with the Abre VS in central venous lesions in hemodialysis patients. METHODS: From April 2020 to May 2023, all procedures with Abre VSs placed for central venous lesions in hemodialysis patients were retrospectively analyzed from a prospectively collected database of 980 hemodialysis access interventions. Follow up outcomes were obtained from angiographic images on follow up angiography and included primary patency and primary assisted patency. Effective hemodialysis was considered a surrogate for access patency if no angiographic follow-up was available. RESULTS: A total of 15 patients with CVO were treated with the Abre VS. Technical success was 100%. All patients were able to achieve adequate hemodialysis after VS placement. Stents were placed across the thoracic inlet in 73% of patients. Post procedure primary patency at the target lesion site was 85% at 6 months and 70% at 12 months. Primary assisted patency of the circuit was 93% at 6 and 12 months. No stent fractures were observed. CONCLUSION: Treatment of CVO remains extremely challenging, especially when the lesion is located at the thoracic inlet. In these patients, VSs provide acceptable primary patency rates and allow patients to continue to receive effective hemodialysis. However, routine follow-up and re-interventions will likely be necessary to maintain patency in the long term.

In-thrombus thrombin secretion: a new diagnostic marker of atrial fibrillation in cryptogenic stroke.

Endovascularly retrieved clots may be a potential resource for diagnosing stroke etiology. This method may influence secondary prevention treatment. We measure thrombin activity eluted by serially washing clots. We concluded that an assay measuring the change in thrombin in clots retrieved during acute stroke endovascular thrombectomy procedures may serve as a diagnostic marker of the origin of the clot. The suggested mechanism for these differences may be the clot location before its retrieval, with high blood flow causing thrombin washout in atherosclerotic clots, in contrast to atrium appendage low blood flow retaining high thrombin levels.

In-thrombus thrombin secretion: a new diagnostic marker of atrial fibrillation in cryptogenic stroke.

BACKGROUND: Endovascularly retrieved clots are a potential resource for diagnosing stroke etiology, which may influence secondary prevention treatment. In this study we measured thrombin activity eluted by serially washing clots. METHODS: Clots were retrieved from 68 patients with acute ischemic stroke, freshly frozen and classified by standard criteria into proven atrial fibrillation (AF, 18 patients), atherosclerotic origin (AS, 15 patients), cryptogenic stroke (Cr, 17 patients) and other known causes (18 patients). Thawed clot samples were washed by transferring them into 1 mL buffer in seven hourly cycles and a fluorescent substrate assay was used to measure secreted thrombin activity. The clots were also examined histologically. Artificial fibrin and red blood cell-rich clots were similarly assayed for wash-eluted thrombin activity as an external control. RESULTS: Thrombin activity eluted from clots of AF origin decreased significantly with time in contrast to steady levels eluted from AS origin thrombi (P<0.0001 by repeated measures ANOVA). The Cr stroke group was indistinguishable from the AF group and differed statistically from the AS group (P=0.017 by repeated measures ANOVA). In artificial clots we found a biphasic activity pattern, with initially decreasing levels of eluted thrombin (AF pattern) and then, with continuing washes, steady eluted thrombin levels (AS pattern). CONCLUSIONS: An assay measuring the change in thrombin in clots retrieved during acute stroke endovascular thrombectomy procedures may serve as a diagnostic marker of the origin of the clot. The suggested mechanism for these differences may be the clot location before its retrieval, with high blood flow causing thrombin washout in atherosclerotic clots, in contrast to atrium appendage low blood flow retaining high thrombin levels.

Inguinal lymphadenopathy as a predicting factor for ipsilateral primary limb amputation after a successful endovascular treatment.

PURPOSE: To assess the correlation between inguinal lymph node characteristics and ipsilateral limb amputation rates in patients with ischemic foot ulcers after a successful endovascular treatment. METHOD: A retrospective review of patients who were endovascularly treated for ischemic foot ulcers between January 2015 and May 2017. Technical success was defined as arterial recanalization with stenosis less than 30 % and ankle brachial index improvement by > 0.2 after 24 h. Unilateral lymph node size, contrast enhancement, necrosis, and perinodular fat stranding were assessed on pre-procedural CTA. Primary endpoints were amputation and sepsis within 12 months following treatment. The relationship between lymph node characteristics and limb amputation and septic shock were examined. RESULTS: Endovascular treatment of 202 limbs in 202 patients (135 males; median age 72.8 years [42.2-93.7]) was technically successful. Forty-two (20.8 %) patients underwent amputation, six (3 %) patients had septic shock. There was a significant difference in lymph node sizes between the amputated and the non-amputated limbs (P = 0.000). Lymph node characteristics (size, enhancement, necrosis, and perinodular fat stranding) were significantly related to amputation (P < 0.001). Patients with perinodular fat stranding or increased node size were 5.940 and 1.109 times more likely to undergo limb amputation, respectively. Lymph node characteristics were also significantly related to septic shock (P < 0.05). CONCLUSIONS: Certain lymph node characteristics are associated with amputation in patients with ischemic foot ulcers, after a technically successful endovascular treatment of the limb. Large lymph node size and perinodular fat stranding are predictive of limb amputation.

Primary Retrograde Dorsalis Pedis Artery Single Access for Revascularization of Chronic Total Occlusion in Patients with Critical Limb Ischemia.

PURPOSE: To evaluate the dorsalis pedis artery (DPA) approach as a single access site for revascularization in patients with critical limb ischemia (CLI) when the femoral approach is hostile or unavailable. MATERIALS AND METHODS: A retrospective review of patients who underwent iliac and femoropopliteal ipsilateral revascularization via a single access site from the DPA between January 2017 and February 2018 was performed. Fifteen limbs in 15 patients (10 men and 5 women; average age 72 y; range, 49-96 y) with CLI and unavailable femoral access were included. Patients were unsuitable candidates for a surgical bypass graft. Treated limbs were classified as Rutherford category 5 and 6 in 12 patients and category 4 in 3 patients. Treated occluded segments involved 2 iliac arteries, 12 femoropopliteal arteries, 1 bypass graft, and 2 posterior tibial arteries. Technical success was defined as recanalization of the occluded artery with residual stenosis < 30% and improvement in ankle-brachial index after 24 hours. Patients were followed for up to 13 months. Endpoints were freedom from reintervention and limb salvage for 1 year. RESULTS: Technical success was achieved in 14 of 15 patients (93%). Stents were placed in 13 of 15 patients (86%). No complications were encountered immediately after the procedure. Median follow-up was 7.1 months (range, 1.4-13.5 mo). One patient was lost to follow-up. Reintervention was needed in 5 limbs after an average of 4.2 months. Limb salvage rate at 1 year was 83%. CONCLUSIONS: Using the DPA as a single access could be a valuable approach when traditional access sites are unavailable for treating patients with CLI.

The Aortic Bifurcation Angle as a Factor in Application of the Outback for Femoropopliteal Lesions in Ipsilateral Versus Contralateral Approaches.

PURPOSE: To assess the technical success of the Outback reentry device in contralateral versus ipsilateral approaches for femoropopliteal arterial occlusion. MATERIALS AND METHODS: A retrospective review of patients treated for critical limb ischemia (CLI) using the Outback between January 2013 and July 2016 was performed. Age, gender, length and site of the occlusion, approach site, aortic bifurcation angle, and reentry site were recorded. Calcification score was assigned at both aortic bifurcation and reentry site. Technical success was assessed. RESULTS: During the study period, a total of 1300 endovascular procedures were performed on 489 patients for CLI. The Outback was applied on 50 femoropopliteal chronic total occlusions. Thirty-nine contralateral and 11 ipsilateral antegrade femoral were accessed. The device was used successfully in 41 patients (82%). There were nine failures, all in the contralateral approach group. Six due to inability to deliver the device due to acute aortic bifurcation angle and three due to failure to achieve luminal reentry. Procedural success was significantly affected by the aortic bifurcation angle (p = 0.013). CONCLUSION: The Outback has high technical success rates in treatment of femoropopliteal occlusion, when applied from either an ipsi- or contralateral approach. When applied in contralateral access, acute aortic bifurcation angle predicts procedural failure.