Transradial renal artery angioplasty and stenting

Transradial arterial access is an alternative approach for coronary interventions. The utilization of these cardiac systems may facilitate endovascular treatment of other vascular territories. This report describes our first experience with percutaneous transluminal renal artery angioplasty and stenting (PTRAS) using the transradial approach. This case demonstrates the feasibility of the radial approach to treat severe renal artery disease safely with PTRAS. Comparison with femoral and brachial arterial access sites is beyond the scope of this paper, but the cardiac literature has demonstrated the safety and efficacy of transradial artery access. With refinement of the endovascular equipment, the radial approach could become an attractive alternative entry site for renal artery interventions.     

Reduced store-operated Ca2+ entry impairs mesenteric artery function in response to high external glucose in type 2 diabetic ZDF rats

Diabetes is a major risk factor for cardiovascular disease, affecting both endothelial and smooth muscle cells. Store-operated Ca²⁺ channels (SOCCs) have been implicated in many diabetic complications. Vascular dysfunction is common in patients with diabetes, but the role of SOCCs in diabetic vasculopathy is still unclear. Our research aimed to investigate the effects of high glucose (HG) on store-operated Ca²⁺ entry (SOCE) in small arteries. Small mesenteric arteries from type 2 diabetic Zucker fatty rats (ZDF) versus their non-diabetic controls (Zucker lean, ZL) were examined in a pressurized myograph. Vascular smooth muscle cells (VSMC) were isolated and intracellular Ca²⁺ was measured (Fura 2-AM). A specific protocol to deplete intracellular Ca²⁺ stores and thereby open SOCCs, as well as pharmacological SOCE inhibitors (SKF-96365, BTP-2), were used to artificially activate and inhibit SOCE, respectively. High glucose (40 mmol/L) relaxed arteries in a SKF-sensitive manner. Diabetic arteries exhibited reduced HG-induced relaxation, as well as reduced contraction after Ca²⁺ replenishment. Further, the rise in intracellular Ca²⁺ on account of SOCE is diminished in diabetic versus non-diabetic VSMCs and was insensitive to HG in diabetic VSMCs. The expression of SOCC proteins was measured, detecting a downregulation of Orai1 in diabetes. In conclusion, diabetes leads to a reduction of SOCE and SOCE-induced contraction, which is unresponsive to HG-mediated inhibition. The reduced expression of Orai1 in diabetic arteries could account for the observed reduction in SOCE.     

Suitability of incorporated vascular stents for surgical patch-plasty: An experimental study

Purpose: Evaluate the feasibility of expanding arterial and venous stents incorporated into the vessel wall by surgical patch-plasty in an experimental study. Methods: An 8-mm Wallstent was percutaneously implanted into the carotid artery of 11 sheep and into the ipsilateral jugular vein in three of them. Three months after implantation, a patch-plasty was performed on the incorporated stents using a 0.4-mm-thick synthetic patch made of polytetrafluoroethylene (PTFE). Stent patency was monitored by color-coded duplex ultrasound and angiography for 6 months after operation. Results: No suture dehiscence or aneurysm formation were observed. Nine of 11 arterial and 2 of 3 venous stents remained fully patent during follow-up. In arteries, complications encountered were a complete stent thrombosis early after surgery, as well as a floating thrombus in the stent, found at final angiography after 6 months. In veins, one partial stent thrombosis was observed. Microradiographic and histological examinations revealed marked intimal hyperplasia in both arterial and venous stents. Intimal hyperplasia was significantly more pronounced in patched than in stented arterial segments (p<0.005). Conclusion: Patch-plasty surgery of previously incorporated vascular stents is technically feasible. Midterm patency rates were acceptable.     

Use of a cutting balloon for dilatation of a resistant venous stenosis of a hemodialysis fistula

In a 71-year-old patient with a Brescia-Cimino hemodialysis fistula, high-pressure balloon dilatation failed to open the stenosis completely and a constant waist of the balloon was found. The use of a 3.5-mm coronary cutting balloon (Barath balloon) was helpful in preparing the stenosis for subsequent successful dilatation.     

Stent Placement on Fresh Venous Thrombosis

Purpose: To report on the efficacy of fixing fresh venous thrombus to the venous wall by stent placement. Methods: Seven patients underwent stenting to treat acute venous thrombosis. In two patients, the hemodialysis fistula was thrombosed with the thrombus extending into the brachial veins. In three patients, the hemodialysis fistula was patent but massive swelling of the ipsilateral arm was caused by proximal venous thrombosis. Two patients presented with iliac venous thrombosis within stented pelvic veins. Stent placement was preceded by other mechanical thrombectomy methods in all cases. Results: Attachment of thrombus to the venous wall was successful in all cases treated. Acute rethrombosis did not occur. Follow-up patency in dialysis patients was 7.2 ± 2.1 months. One patient had rethrombosis of the dialysis graft 3 months after primary treatment. Three patients developed restenosis within a mean period of 7.7 months. One shunt remained patent for 10 months with no event of reobstruction during follow-up. In both patients with iliac stent placement, the vein remained patent over a follow-up period of 8 and 12 months respectively. Conclusion: Stenting fresh venous thrombus can achieve immediate venous patency. It may be used as an alternative approach when all other percutaneous methods fail. Frequent restenosis within stented veins limits its use to very selected cases. Received: 0/00/00/Accepted: 0/00/00     

A simple trick to facilitate bleeding control after percutaneous hemodialysis fistula and graft interventions

A simple technique of performing a circular subcutaneous suture that helps to stop bleeding after cannulation of hemodialysis grafts and fistulas following percutaneous revision is described.