Association of anaesthesia technique with 30-day primary graft patency after open lower limb revascularization: retrospective cohort study.

BACKGROUND: The relationship between anaesthetic technique and graft patency after open lower limb revascularization is unclear. The aim of this study was to evaluate the association between 30-day graft patency after elective infrainguinal bypass and anaesthetic technique (regional anaesthesia (RA, i.e. neuraxial and/or peripheral nerve blockade) compared with general anaesthesia (GA)). METHODS: Patients who underwent elective infrainguinal bypass in the 2014-2019 National Surgical Quality Improvement Program Vascular Procedure Targeted Lower Extremity Open data set were included. Excluded patients were those under 18 years old, those who did not receive RA or GA, and/or had an international normalized ratio of 1.5 of greater, a partial thromboplastin time more than 35 s, or a platelet count less than 80 × 109/L. The primary outcome was primary graft patency without reintervention. The relationship between anaesthetic technique and patency was analysed with multivariable logistic regression. RESULTS: Included were 8893 patients with a mean(s.d.) age of 68(11) years and 31.5 per cent female. Within the cohort, 7.7 per cent (n = 688) patients received RA only, 90.4 per cent (n = 8039) GA only, and 1.9 per cent (n = 166) both GA and RA. In the RA-only group, 91.7 per cent (631 of 688) received neuraxial anaesthesia. The primary patency rate was 93.2 per cent (573 of 615) for RA only, and 91.5 per cent (6390 of 6983) for GA only (standardized mean difference, 0.063). RA was not associated with a higher rate of patency compared with GA (adjusted OR, 1.16; 95 per cent c.i., 0.83 to 1.63; P = 0.378). CONCLUSION: There was no association between anaesthetic technique and 30-day graft patency after elective infrainguinal bypass surgery. Further prospective studies would be useful to study the impact of anaesthesia technique on important patient-centred outcomes such as long-term patency and non-home discharge.

Tailoring intermolecular interactions to develop a low-temperature electrolyte system consisting of 1-butyl-3-methylimidazolium iodide and organic solvents.

Ionic liquids (ILs) exhibit remarkable properties and great tunability, which make them an attractive class of electrolyte materials for a variety of electrochemical applications. However, despite the promising progress for operating conditions at high temperatures, the development of their low-temperature viability as electrolytes is still limited due to the constrains from thermal and ion transport issues with a drastic decrease in temperature. In this study, we present a liquid electrolyte system based on a mixture of 1-butyl-3-methylimidazolium iodide ([BMIM][I]), γ-butyrolactone (GBL), propylene carbonate (PC), and lithium iodide (LiI) and utilize its molecular interactions to tailor its properties for extremely low-temperature sensing applications. In particular, the carbonyl group on both PC and GBL can form hydrogen bonds with the imidazolium cation, as indicated by Fourier transform infrared spectroscopy (FTIR), and the extent of these interactions between ions and molecules was also characterized and quantified via proton nuclear magnetic resonance (1H NMR) spectroscopy. More importantly, at the optimal ratio, the organic solvents do not have excess content to form aggregates, which may cause undesired crystallization before the glass transition. The microscopic evolutions of the systems are correlated with their bulk behaviors, leading to improvements in their thermal and transport properties. The optimized formulation of [BMIM][I]/PC/GBL/LiI showed a low glass transition temperature (T g) of -120 °C and an effectively reduced viscosity of 0.31 Pa s at -75 °C. The electrochemical stability of the electrolyte was also validated to support the targeted iodide/triiodide redox reactions without interference.

A comparison of revision using distal inflow and distal revascularization-interval ligation for the management of severe access-related hand ischemia.

OBJECTIVE: Access-related hand ischemia (ARHI) is a potentially limb-threatening complication of arteriovenous access for dialysis. The distal revascularization-interval ligation (DRIL) and revision using distal inflow (RUDI) procedures both allow treatment of ischemic symptoms while maintaining fistula patency. Although outcomes with the DRIL are well established, experience with the RUDI for ARHI remains preliminary. We compared outcomes in these procedures with respect to cumulative patency, resolution of symptoms, and patient survival. METHODS: A large, prospectively maintained database was used to identify all patients after autogenous arteriovenous fistula construction at two hospitals between 2005 and 2015. Patients with severe Society for Vascular Surgery grade 3 ARHI were included for analysis. RESULTS: A total of 2035 autogenous accesses were created during the study period, and 58 (3%) developed grade 3 ARHI. Of this cohort, RUDI was performed in 20 and DRIL in 21. The indication for intervention was tissue loss (61%) or ischemic rest pain (39%). Mean age was 57.5 years, and 54% of patients were female. Most patients had diabetes (86%) and symptomatic peripheral arterial disease (63%). The mean preoperative digital-brachial index was 0.25 ± 0.12. There were no preoperative differences in patient comorbidities between the RUDI and DRIL cohorts. Primary patency between the RUDI and DRIL cohorts at 12 months (58% ± 11% vs 55% ± 12%) and 36 months (51% ± 12% vs 41% ± 12%) were similar (P = .841). Cumulative secondary patency at 12 months (84% ± 8% vs 94% ± 6%) and 36 months (78% ± 9% vs 86% ± 9%) showed no significant difference (P = .398). Resolution of ischemic symptoms, including resolution or improvement in pain or healing of ischemic ulcers or amputations, occurred in 90% with RUDI and in 81% with DRIL (P = .131). Survival for patients who underwent RUDI or DRIL procedures at 1 and 3 years was 85% vs 86% (P = .948) and 55% vs 49% (P = .278). CONCLUSIONS: In this preliminary study, the RUDI demonstrated similar patency, symptom resolution, and survival compared with the DRIL for patients with severe ARHI. All-cause mortality after any procedure for severe steal syndrome is high, and the particular intervention for management of steal must account for anatomic-, patient-, and disease-related considerations.

Antegrade balloon occlusion of inferior vena cava during thrombectomy for renal cell carcinoma.

Nephrectomy with inferior vena cava (IVC) thrombectomy for advanced renal cell carcinoma (RCC) is a challenging and morbid surgical case. We describe the use of a simple endoluminal technique to occlude the suprahepatic IVC during thrombectomy. A 60-year-old male presented with a large right-sided RCC and IVC tumour thrombus. The tip of the thrombus, which was non-adherent to the caval wall, extended to the level of the hepatic veins. After complete dissection of the kidney, we obtained suprahepatic control of the IVC by a large compliant balloon, introduced through the right internal jugular vein and inflated just below the level of the diaphragm. The IVC thrombectomy was performed in a bloodless field. Mean blood pressure remained stable during IVC balloon inflation with a total occlusion time of 10 minutes. Intraprocedural completion cavogram and postoperative Doppler ultrasonography showed no residual IVC clot. Blood loss during the thrombectomy portion of the case was scant. The patient's postoperative course was uncomplicated and, at the last follow-up, he had stable metastatic disease on sunitinib therapy. For the surgical treatment of RCC with retrohepatic IVC tumour extension, transjugular balloon occlusion of the suprahepatic IVC offers an alternative to extensive hepatic mobilization to obtain suprahepatic thrombus control. Advantages over traditional surgical methods may include decreased surgical time, lower risk of liver injury and tumour embolism. We suggest this method for further evaluation.

Endovascular aortic aneurysm repair via the left ventricular apex of a beating heart.

An elderly man presented with a ruptured aortic arch, left lung compression, and hemoptysis. Multiple comorbidities and inadequate aortoiliac access disqualified him from conventional open repair or hybrid retrograde transarterial thoracic endovascular aortic repair (TEVAR). Because our center has recently reported that a thoracic aortic endograft can be successfully placed through the apex of the LV of a beating heart in a pig model, we received approval for the compassionate use of antegrade transapical TEVAR (TaTEVAR) with bilateral femoral-carotid revascularization to repair the aortic arch. As in our animal model, TaTEVAR was performed with accuracy and minimal hemodynamic compromise. The patient was quickly weaned from inotropic and respiratory support postoperatively and was neurologically intact, but died on the tenth postoperative day from respiratory failure.

Successful ventricular transapical thoracic endovascular graft deployment in a pig model.

PURPOSE: Aortoiliac occlusive disease may preclude retrograde thoracic endovascular aortic repair. This study evaluated the physiologic and anatomic feasibility of introducing an aortic endograft in an antegrade manner into the descending thoracic aorta of a pig through the left ventricular apex. METHODS: Twelve adult pigs were to undergo antegrade endograft deployment. Under fluoroscopic guidance, a stiff guidewire was introduced past the aortic valve and into the distal abdominal aorta through the left ventricular apex on a beating heart. An 18F introducer sheath containing a 24 x 36-mm aortic endograft was introduced and deployed in the descending thoracic aorta. The accuracy of graft delivery was determined at necropsy by measuring the distance from the trailing edge of the graft to the downstream margin of the ostium of the left subclavian artery. Aortic valve competency was assessed angiographically and at necropsy. Left ventricular function was assessed angiographically. Five hemodynamic and respiratory variables were recorded at 12 stages during the procedure and assessed for significant changes from baseline. RESULTS: One animal died during the sternotomy. All remaining pigs survived the experiment with minimal hemodynamic support. A significant drop in systolic blood pressure (75 +/- 2 to 60 +/- 4 mm Hg, P = .05) was noted when the aortic valve was crossed with an 18F sheath. The systolic blood pressure returned to baseline on endograft deployment and at the end of the procedure. Bradycardia was noted at several stages of the procedure, requiring treatment in two pigs. Eleven endografts were deployed; seven grafts were delivered within 5 mm and three grafts within 10 to 20 mm of the intended landing point. One graft was deployed 10 mm too proximally, covering the left subclavian artery. No aortic valvular insufficiency or left ventricular dysfunction was noted. CONCLUSION: An aortic endograft can be delivered in an antegrade manner transapically into the descending thoracic aorta in a pig model with a reasonable degree of accuracy and minimal hemodynamic compromise.

Percutaneous closure of a para-anastomotic abdominal aortic graft leak.

Para-anastomotic graft leaks are a potential complication following surgical repair of an aortic aneurysm. Reoperation may be associated with significant morbidity and mortality. We report successful percutaneous transcatheter closure of an anastomotic graft leak utilizing an occluder device.

Results of prosthetic-vein composite graft with remote popliteal arteriovenous fistula in infragenicular bypass.

OBJECTIVE: The purpose of this study is to report the results of a novel procedure for femoral-distal bypass grafting using a composite graft with an adjunctive remote popliteal fistula distal to the prosthetic portion of the graft. This reconstruction was developed for use in limb salvage in the absence of satisfactory autogenous vein. METHOD: Data were collected prospectively on all patients undergoing this procedure from January 1, 1993 to December 31, 1999. Graft patency was determined from follow-up duplex scanning. Patient survival was determined by clinic follow-up. RESULTS: A total of 43 procedures were performed in 38 patients. In 34 patients, 72 previous arterial operations had been previously performed on the ipsilateral limbs. There were 20 men and 18 women with a mean age of 72 years. The indication for surgery was limb salvage in all, with rest pain in 30, and tissue loss in 13. The outflow artery was the below-knee popliteal artery in 10 and a tibial artery in the remainder. Operative mortality was 6.8%. Mean follow up was 26.9 months. The primary patency was 54% at 12 months. Six reconstructions were revised for a primary assisted patency of 60% at 16 months. Secondary patency was 69% at 16 months. Patient survival was 62% at 2 years and 26% at 5 years. CONCLUSIONS: The technique of composite grafting with remote popliteal arteriovenous fistula may be a useful alternative in infragenicular bypass when a satisfactory autogenous vein is not available.