Vascular access challenges in hemodialysis patients with superior vena cava syndrome.

BACKGROUND: Superior vena cava syndrome in hemodialysis patients resulting from previous or current use of a tunneled central vein catheter is a rare but potentially severe condition. Two aspects have to be addressed during management and treatment: the restoration of central venous flow and the creation of an alternative vascular access to guarantee hemodialysis. RESEARCH DESIGN: Conforming to the current guidelines and literature, we present a stepwise approach and discuss therapeutic options. The removal of the tunneled central vein catheter should be attempted and a native vascular access created whenever feasible. RESULTS: First, an upper extremity AVF should be preserved or, as in our case, made functional. Endovascular treatment of CVSO should primarily consist of balloon dilatation. Placement of a stent or stent graft should be considered as a secondary option. HeRO graft placement may be considered in recurrent CVSO and recanalization with a Surfacer. LL-AVF or AVG need to be discussed and may be an alternative for certain HD patients when the risk of lower limb ischemia and infection is considered. CONCLUSION: Several therapeutic options are available and the basic principles are well established in the literature, although the level of evidence is not high. Therefore, we propose a stepwise and interdisciplinary approach to guide the challenging decision-making process in SVC.

A Novel Percutaneous Technique for Aorto-Iliac Thrombectomy without the Risk of Embolization.

Classic surgical thrombectomy of the aorta and iliac arteries through an incision in the groin vessels harbors the risk of embolization to the viscero-renal as well as hypogastric arteries, while percutaneous endovascular thrombectomy techniques can lead to peripheral embolization to the lower limbs. Therefore, we describe a novel, percutaneous technique that tackles the above issues. Furthermore, we also present our initial experience using the technique. The principle of the technique is to percutaneously place large-bore sheaths in the iliac arteries that deliberately occlude the latter to protect the lower limbs from embolization. Through one of these sheaths, over wire Fogarty® catheters can be placed and inflated in the ostia of the coeliac trunk, superior mesenteric artery, renal arteries, and hypogastric arteries as needed. A large thrombectomy balloon catheter is then used to bring any aorto-iliac thrombus into the sheaths, whereafter the thrombus is removed from the sheaths by simply deflating their valves. Additional endovascular procedures of the aorto-iliac branches can be performed as needed. We report nine procedures in 8 patients (4 males and 4 females) with a median age of 63 (53-68.5). Additional endovascular procedures were performed in 6 (66.7%) procedures. All but one procedure were technically successful, and all patients had palpable foot pulses on completion of the procedures, while no patient had clinical signs of peripheral embolization. This technique is a very valid addition to the vascular surgeon's armamentarium when treating aorto-iliac thrombotic events because it is minimally invasive while still protecting against embolization and offering the flexibility to perform a wide range of additional endovascular procedures where needed.

Therapeutic arteriogenesis by factor-decorated fibrin matrices promotes wound healing in diabetic mice.

Chronic wounds in type-2 diabetic patients present areas of severe local skin ischemia despite mostly normal blood flow in deeper large arteries. Therefore, restoration of blood perfusion requires the opening of arterial connections from the deep vessels to the superficial skin layer, that is, arteriogenesis. Arteriogenesis is regulated differently from microvascular angiogenesis and is optimally stimulated by high doses of Vascular Endothelial Growth Factor-A (VEGF) together with Platelet-Derived Growth Factor-BB (PDGF-BB). Here we found that fibrin hydrogels decorated with engineered versions of VEGF and PDGF-BB proteins, to ensure protection from degradation and controlled delivery, efficiently accelerated wound closure in diabetic and obese db/db mice, promoting robust microvascular growth and a marked increase in feeding arterioles. Notably, targeting the arteriogenic factors to the intact arterio-venous networks in the dermis around the wound was more effective than the routine treatment of the inflamed wound bed. This approach is readily translatable to a clinical setting.

Temporary Extracorporeal Femoro-Femoral Crossover Bypass to Treat Acute Limb Ischemia due to Occlusive Femoral Transaortic Microaxial Left Ventricular Assist Device - A Novel Technique and Case Series.

BACKGROUND: The Impella transaortic microaxial left ventricular assist device (MLVAD) bears the risk of severe ipsilateral limb ischemia due to its percutaneous insertion through the common femoral artery (CFA). As long as the MLVAD is required for cardio - circulatory support, treatment options are limited. Therefore, we developed a temporary extracorporeal femoral - femoral crossover bypass to restore and maintain perfusion of the affected leg. METHODS: From October 2018, we treated all patients with severe limb ischemia due to the MLAVD with a femoral - femoral crossover bypass. For comparison, a consecutive cohort of patients undergoing placement of the MLAVD between January 2011 and October 2018 was identified. The primary outcome is the feasibility and safety of our percutaneously established extracorporeal femoral - femoral crossover bypass. RESULTS: Between January 2011 and July 2019, 25 of 245 (10.3%) patients developed a severe ipsilateral limb ischemia following the MLVAD placement. Until October 2018, 20 patients were treated conventionally (C - cohort) and since October 2018, five (consecutive) patients have been treated by an extracorporeal femoral - femoral cross over bypass (BP - Cohort). Following the BP - procedure, an immediate improvement of the perfusion was seen in all patients. Limb salvage was documented in 100% of our patients and 30 - day mortality was 60% in both groups. CONCLUSION: This is the first case series reporting on this novel technique. We demonstrated that the percutaneous creation of an extracorporeal crossover bypass is feasible, safe and effective and should therefore be promoted.

Robust Angiogenesis and Arteriogenesis in the Skin of Diabetic Mice by Transient Delivery of Engineered VEGF and PDGF-BB Proteins in Fibrin Hydrogels.

Non-healing ulcers are a serious complication of diabetes mellitus and a major unmet medical need. A major cause for the lack of healing is the impairment of spontaneous vascularization in the skin, despite mostly normal blood flow in deeper large vessels. Therefore, pro-angiogenic treatments are needed to increase therapeutic perfusion by recruiting new arterial connections (therapeutic arteriogenesis). Vascular endothelial growth factor (VEGF) is the master regulator of angiogenesis in physiology and disease, but exploitation of its therapeutic potential requires careful control of its dose distribution in tissue. Co-delivery of platelet derived growth factor-BB (PDGF-BB) has been shown to expand the therapeutic window of VEGF and also improve associated arteriogenesis. We used a highly controlled protein delivery system, based on a clinically applicable fibrin-based platform, to investigate the angiogenic and arteriogenic potential of engineered versions (TG-) of VEGF and PDGF-BB proteins in the skin of diabetic and obese db/db mice. Intradermal delivery of therapeutically relevant doses of TG-VEGF and TG-PDGF-BB induced robust growth of new microvascular networks with similar efficacy as in normal littermate control mice. Further, TG-PDGF-BB prevented the formation of aberrant vascular enlargements by high TG-VEGF levels. As fibrin was degraded after the first week, the induced angiogenesis mostly regressed by 4 weeks, but it promoted effective arteriogenesis in the dermal layer. Therefore, controlled co-delivery of TG-VEGF and TG-PDGF-BB recombinant proteins is effective to induce angiogenesis and arteriogenesis in diabetic mouse skin and should be further investigated to promote diabetic wound healing.

Plication for the treatment of a radio-cephalic fistula with ulnar artery steal.

PURPOSE: Generally the steal syndrome occurs in proximal arterial-venous fistulas and only exceptionally with distal vascular access because of the high number of arteries supplying the hand. We describe a rare case of steal syndrome of a proximalized distal radio-cephalic fistula stealing from both the radial and ulnar artery through the palmar arch. METHODS: An 86 year old man was admitted because of a cyanotic, swollen left hand with trophic lesions at the third finger. He had a latero-terminal radio-cephalic fistula performed in 2006 with subsequent proximalization performed four years later after failure of the first one. Duplex ultrasound examination showed a high flow within the fistula (2080 mL/min) and a retrograde perfusion of the radial artery from the ulnar artery through the palmar arch and an angiography excluded stenosis along the radial artery. RESULTS: We treated the steal syndrome through a plication technique that was performed with careful flow variations measurement, under duplex evaluation, during the surgical procedure. That procedure was effective to maintain the fistula flow and obtain the symptoms relief. The patient was evaluated the day after the intervention and after 10 weeks. The clinical examination highlighted the resolution of hand ischemia. The Duplex Ultrasound examination showed a lower flow within the fistula (1060 mL/min) and a retrograde perfusion of the radial artery from the ulnar artery through the palmar arch with a three-phase flow. dialysis access from the fistula was never interrupted from immediately after surgery to the present date. CONCLUSIONS: Plication is an effective technique for treatment of steal syndrome requiring a short operative time and it is related to satisfying post-operative results.

Impact of duplex ultrasound surveillance program on patency of prosthetic arteriovenous graft for hemodialysis: a single-center experience.

BACKGROUND: Arteriovenous prosthetic graft (AVG) is an alternative hemodialysis vascular access choice; however, its performance is limited by a high rate of thrombosis. The aim of the study was to compare the long-term secondary patency of AVG in patients undergoing a surveillance program and the long-term secondary patency of AVG in patients with clinical assessment of AVG malfunction. METHODS: From 2009 to 2012, all patients with AVG entered in a duplex ultrasound (DUS) surveillance program (at 3 months and then every 6 months postoperatively) to assess AVG malfunction and/or stenosis (stenosis >50% and blood flow decrease [<600 mL/min]) and eventually treated by endovascular revascularization. AVG long-term patency in the surveillance group was compared with that obtained in a historical control group in which the malfunction was clinically detected. As secondary end point, the central vein catheter (CVC) placement after AVG thrombosis was compared in the 2 groups. RESULTS: Sixty patients were included in the study, 33 (55%) in the surveillance program and 27 (45%) in the historical group. The 2 groups had similar clinical characteristics and follow-up (59, interquartile range [IQR]: 45 vs. 56 [IQR, 40 months], P = 0.32). Fifteen (45%) AVG malfunctions were detected in the surveillance group and successfully treated (10 [66.6%] angioplasty and 5 [33.4%] angioplasty stenting). No malfunction was detected in the historical control group. By Kaplan-Meier analysis, the 5-year secondary patency was significantly higher in the surveillance group compared with the historical group: 42 ± 13% vs. 9 ± 7%, P = 0.03. By Cox analysis, the DUS surveillance was a significantly protective factor for AVG thrombosis, otherwise the use of CVC before the AVG and diabetes mellitus were AVG thrombosis risk factors. The CVC placement was significantly lower in the surveillance group compared with the historical group (14.0% vs. 42.2%, P = 0.02). CONCLUSIONS: The DUS surveillance allows a greater secondary patency compared with a clinical evaluation and reduces CVC placement rate.