Pre-operative regional block anesthesia enhances operative strategy for arteriovenous fistula creation.

PURPOSE: We aim to assess the effect of regional block anesthesia on vein diameter, type of AVF placement, and fistula size and flow volume. METHODS: 30 patients presenting for AV access procedures were followed prospectively. Vein diameters via venous ultrasound and planned location for AV access were documented. Supraclavicular brachial plexus block was followed by repeat ultrasound and alterations in operative plan were noted. Patients returned to clinic for duplex ultrasound assessment. RESULTS: Average increase from baseline vein diameter with regional block was most pronounced in the lower cephalic (34%), upper cephalic (24.2%), and basilic veins (31.3%) and less in the brachial vein (8.7%). Type of AVF was modified following regional block in 14%. The rate of native AVF placement improved from 89% to 93% with regional block. Twenty-three AVF patients were available for follow-up (mean 24 weeks). Average fistula size was 7.9 mm (CI 6.9-8.9) and all patent fistulas developed flow volume >600 mL/min. Primary patency was attained in 83%. One thrombosis occurred after a basilic artery was lacerated during dialysis access. The average fistula increased 0.33 cm from post-block diameter (SD 0.22, P<.05). CONCLUSIONS: Vein diameter increases significantly in the basilic and cephalic veins following regional block anesthesia and may improve the rate of native fistula placement. Propensity to dilate after regional block anesthesia does not predict size of the fistula.

Aortic remodeling, volumetric analysis, and clinical outcomes of endoluminal exclusion of acute complicated type B thoracic aortic dissections.

OBJECTIVE: Structural changes within the aorta after thoracic endovascular aortic repair (TEVAR) for acute complicated type B thoracic aortic dissections (ABAD) remain unknown. This study reviewed and analyzed morphologic changes, volumetric data, and clinical outcomes of patients with ABAD. METHODS: Forty-one consecutive patients with ABAD, all with the volumetric analysis of aortic luminal changes and ≥1 year of follow-up, were treated as a part of a single-center U.S. Food and Drug Administration (FDA)-approved investigational device exemption (IDE) trial from 2002 to 2009. Indications were malperfusion in 17, rupture in 12, chest pain in 6, acute enlargement in 4, and uncontrolled hypertension in 2. Duration of symptoms was ≤14 days. Three-dimensional M2S computed tomography reconstructions (Medical MetRx Solutions, West Lebanon, NH) were analyzed for aortic volume and diameter changes, regression of the false lumen, and expansion of the true lumen. RESULTS: Emergent surgery was required in 17 (42%) patients, excluding one death at induction. Procedural success rate was 92.5%. The 30-day mortality was 4.9% for malperfusion, 4.9% for rupture, and 0% for all others, with late mortality of 0%, 9.8%, and 7.3%, respectively. Mean follow-up was 12.4 months. Permanent stroke and paraplegia rates were 4.9% (n = 2) and 0%. Ten of 12 secondary interventions were performed for 6 proximal endoleaks, 1 distal cuff endoleak, and 3 distal reperfusions. For the 33 patients without endoleaks, the true lumen volume increased by 29% at 1 month, 51% at 1 year, and 80% at 5 years. Volume regression of the false lumen was 69%, 76%, and 86%, respectively. The true lumen volume did not change at 1 month or 1 year in the endoleak group (n = 7) but increased 50% at 2 years after secondary intervention. A 10% reduction of abdominal aortic volume distal to endograft occurred over 5 years in the absence of endoleaks. CONCLUSIONS: TEVAR offers a promising solution to patients with ABAD. Aortic morphologic changes occur shortly after TEVAR and remain predictable up to 5 years with continuous expansion of the true lumen and regression of the false lumen. A lack of increase in the true lumen volume is associated with endoleaks or distal reperfusion.

Scrotal necrosis following endovascular abdominal aortic aneurysm repair.

Scrotal necrosis is an extremely rare complication following endovascular abdominal aortic aneurysm repair. Sloughing of scrotal skin and penile necrosis owing to therapeutic hypogastric artery occlusion for endoluminal aortoiliac aneurysm repair have been documented. We present herein one case of scrotal necrosis following endovascular abdominal aortic aneurysm repair. The presentation of combined scrotal necrosis, buttock ischemia, lower extremity livedo reticularis, and left blue toes with palpable pulses in the posterior tibial and dorsalis pedis arteries suggested that microembolization during endovascular aneurysm repair was the major cause of the devastating ischemic complications in this patient.

Duplex ultrasound surveillance can be worthwhile after arterial intervention.

A surveillance program based on duplex ultrasound testing after peripheral arterial intervention can increase long-term patency by identifying and by repairing clinical significant lesions. Its successful application requires numerous conditions regarding pathobiology of arterial repair failure and its consequences, arterial testing expertise, and durability of secondary procedures used to repair duplex-detected lesions. The methodology of surveillance should be tailored to the type of arterial intervention. Clinical reports on the efficacy of duplex ultrasound surveillance have supported its routine use, but controversy of cost-effectiveness remains. Duplex surveillance will decrease procedural primary patency, but when successful, the primary-assisted and secondary patency rates should be significantly higher than the rates when no surveillance was performed. An examination of the primary, primary-assisted, and secondary patency rates of an arterial procedure will indicate the benefit (or lack of benefit) of a surveillance program and the appropriateness of the threshold criteria used for secondary interventions.

The application of duplex surveillance after carotid intervention.

Carotid duplex ultrasound testing provides a safe and accurate method to detect and grade the severity of atherosclerotic internal carotid artery stenosis both before and following carotid intervention. Testing after surgical endarterectomy or stent angioplasty allows assessment of the technical success by excluding residual stenosis. The focus of duplex surveillance after carotid intervention is to identify recurrent stenosis, repair site occlusion, and progression of contralateral internal carotid artery disease. Patients who develop a neurologic event or a duplex-detected >75% diameter-reducing internal carotid artery stenosis with a peak systolic velocity >300 cm/s and end-diastolic velocity >125 cm/s should be further evaluated by angiographic imaging and should be considered for reintervention if an appropriate lesion is confirmed. Duplex surveillance allows the vascular surgeon to evaluate patency of the rendered intervention, its stenosis-free durability, and its effectiveness in stroke prevention.