Assessment of left atrial volume before and after pulmonary thromboendarterectomy in chronic thromboembolic pulmonary hypertension.

BackgroundImpaired left ventricular diastolic filling is common in chronic thromboembolic pulmonary hypertension (CTEPH), and recent studies support left ventricular underfilling as a cause. To investigate this further, we assessed left atrial volume index (LAVI) in patients with CTEPH before and after pulmonary thromboendarterectomy (PTE).MethodsForty-eight consecutive CTEPH patients had pre- & post-PTE echocardiograms and right heart catheterizations. Parameters included mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index, LAVI, & mitral E/A ratio. Echocardiograms were performed 6 ± 3 days pre-PTE and 10 ± 4 days post-PTE. Regression analyses compared pre- and post-PTE LAVI with other parameters.ResultsPre-op LAVI (mean 19.0 ± 7 mL/m2) correlated significantly with pre-op PVR (R = -0.45, p = 0.001), mPAP (R = -0.28, p = 0.05) and cardiac index (R = 0.38, p = 0.006). Post-PTE, LAVI increased by 18% to 22.4 ± 7 mL/m2 (p = 0.003). This change correlated with change in PVR (765 to 311 dyne-s/cm5, p = 0.01), cardiac index (2.6 to 3.2 L/min/m2, p = 0.02), and E/A (.95 to 1.44, p = 0.002).ConclusionIn CTEPH, smaller LAVI is associated with lower cardiac output, higher mPAP, and higher PVR. LAVI increases by ~20% after PTE, and this change correlates with changes in PVR and mitral E/A. The rapid increase in LAVI supports the concept that left ventricular diastolic impairment and low E/A pre-PTE are due to left heart underfilling rather than inherent left ventricular diastolic dysfunction

“Off-the-shelf” devices for complex aortic aneurysm repair

BACKGROUND: Fenestrated devices currently require a 3- to 4-week manufacturing period before implantation; as such, there have been efforts to develop "off-the-shelf" (OTS) devices to reduce the time before definitive treatment can be accomplished. We examined all patients treated for complex aortic problems at our institution during the past 12 months to evaluate the suitability and early outcomes of the OTS devices vs commercially available endovascular options. METHODS: Between July 2012 and September 2013, patients undergoing aortic aneurysm repair were extracted from a prospectively managed aortic database. Two OTS devices, the Cook (Bloomington, Ind) p-Branch and the Endologix (Irvine, Calif) Ventana device, were being evaluated through clinical trials during this time frame. The custom Cook Zenith fenestrated endovascular (ZFEN) device was also available and approved by the U.S. Food and Drug Administration (FDA) during the study period. RESULTS: Of 224 aortic aneurysms treated at our institution during this period, there were a total of 85 patients with type IV thoracoabdominal aneurysms including juxtarenal aneurysms. Only 23 patients (27%) met anatomic criteria for OTS devices, with 16 patients having these investigational devices implanted. The major exclusion criterion for the p-Branch device was renal axial or circumferential position; the limiting factor for Ventana was infrasuperior mesenteric artery neck length restriction. Five of the patients who would have fit criteria for an OTS device had an FDA-approved (ZFEN) device implanted instead, and two patients opted for open repair as a result of follow-up requirements. An additional 25 patients received custom-designed (ZFEN) devices (n = 30; 35%), whereas 37 (44%) others did not meet criteria for any available endovascular device and were repaired with alternative management strategies. The mean age and maximal aortic diameter of the two cohorts (OTS and ZFEN) were 71.8 years and 72.7 years (P = NS) and 61.3 mm and 58.5 mm (P = NS), respectively. Technical success was 100%, with an overall 30-day mortality of 2.1% (n = 1, ZFEN). Major complications occurred in eight patients (17%; two OTS, six ZFEN). CONCLUSIONS: Whereas OTS device strategies will reduce the waiting times for patients with complex aortic aneurysmal disease, a significant number will still require custom-made device repair until additional device designs become available. Early experience with OTS devices does not demonstrate any significant renal risks; however, the treatment numbers are low and should be interpreted with caution until larger confirmatory studies are published. Further studies comparing the outcomes of these techniques are required to establish the best approach to handle endovascular repair of complex aortic aneurysm

“Off-the-shelf” devices for complex aortic aneurysm repair

BACKGROUND: Fenestrated devices currently require a 3- to 4-week manufacturing period before implantation; as such, there have been efforts to develop "off-the-shelf" (OTS) devices to reduce the time before definitive treatment can be accomplished. We examined all patients treated for complex aortic problems at our institution during the past 12 months to evaluate the suitability and early outcomes of the OTS devices vs commercially available endovascular options. METHODS: Between July 2012 and September 2013, patients undergoing aortic aneurysm repair were extracted from a prospectively managed aortic database. Two OTS devices, the Cook (Bloomington, Ind) p-Branch and the Endologix (Irvine, Calif) Ventana device, were being evaluated through clinical trials during this time frame. The custom Cook Zenith fenestrated endovascular (ZFEN) device was also available and approved by the U.S. Food and Drug Administration (FDA) during the study period. RESULTS: Of 224 aortic aneurysms treated at our institution during this period, there were a total of 85 patients with type IV thoracoabdominal aneurysms including juxtarenal aneurysms. Only 23 patients (27%) met anatomic criteria for OTS devices, with 16 patients having these investigational devices implanted. The major exclusion criterion for the p-Branch device was renal axial or circumferential position; the limiting factor for Ventana was infrasuperior mesenteric artery neck length restriction. Five of the patients who would have fit criteria for an OTS device had an FDA-approved (ZFEN) device implanted instead, and two patients opted for open repair as a result of follow-up requirements. An additional 25 patients received custom-designed (ZFEN) devices (n = 30; 35%), whereas 37 (44%) others did not meet criteria for any available endovascular device and were repaired with alternative management strategies. The mean age and maximal aortic diameter of the two cohorts (OTS and ZFEN) were 71.8 years and 72.7 years (P = NS) and 61.3 mm and 58.5 mm (P = NS), respectively. Technical success was 100%, with an overall 30-day mortality of 2.1% (n = 1, ZFEN). Major complications occurred in eight patients (17%; two OTS, six ZFEN). CONCLUSIONS: Whereas OTS device strategies will reduce the waiting times for patients with complex aortic aneurysmal disease, a significant number will still require custom-made device repair until additional device designs become available. Early experience with OTS devices does not demonstrate any significant renal risks; however, the treatment numbers are low and should be interpreted with caution until larger confirmatory studies are published. Further studies comparing the outcomes of these techniques are required to establish the best approach to handle endovascular repair of complex aortic aneurysm

Coverage of the left subclavian artery during thoracic endovascular aortic repair

BackgroundThoracic aortic stent grafts require proximal and distal landing zones of adequate length to effectively exclude thoracic aortic lesions. The origins of the left subclavian artery and other aortic arch branch vessels often impose limitations on the proximal landing zone, thereby disallowing endovascular repair of more proximal thoracic lesions.MethodsBetween October 2000 and November 2005, 112 patients received stent grafts to treat lesions involving the thoracic aorta. The proximal aspect of the stent graft partially or totally occluded the origin of at least one great vessel in 28 patients (25%). The proximal attachment site was in zone 0 in one patient (3.6%), zone 1 in three patients (10.7%), and zone 2 in 24 patients (85.7%). Patients with proximal implantation in zones 0 or 1 underwent debranching procedures of the supra-aortic vessels before stent graft repair. In one patient who underwent zone 1 deployment, the left subclavian artery was revascularized before stent graft deployment. Among patients who underwent zone 2 deployment with partial or complete occlusion of the left subclavian artery, none underwent prior revascularization. Patients were assessed postoperatively and at follow-up for development of neurologic symptoms as well as symptoms of left upper extremity claudication or ischemia.ResultsMean follow-up was 7.3 months. Among the 24 patients with zone 2 implantation, 10 (42%) had partial left subclavian artery coverage at the time of their primary procedure. A total of 19 patients experienced complete cessation of antegrade flow through the origin of the left subclavian artery without revascularization at the time of the initial endograft repair as a result of a secondary procedure or as a consequence of left subclavian artery thrombosis. Left upper extremity symptoms developed in three (15.8%) patients that did not warrant intervention, and rest pain developed in one (5.3%), which was treated with the deployment of a left subclavian artery stent. Two primary (type IA and type III) endoleaks (7.1%) and one secondary endoleak (type IA) (3.6%) were observed in patients who underwent zone 2 deployment. Three cerebrovascular accidents were observed. Thoracic aortic lesions were successfully excluded in all patients who underwent supra-aortic debranching procedures.ConclusionIntentional coverage of the origin of the left subclavian artery to obtain an adequate proximal landing zone during endovascular repair of thoracic aortic lesions is well tolerated and may be managed expectantly, with some exceptions

Treatment of superficial and perforator venous incompetence without deep venous insufficiency: is routine perforator ligation necessary?

Abstract Purpose We investigated whether routine ligation of incompetent perforator veins is necessary in treatment of symptomatic chronic venous insufficiency (CVI) due to combined superficial and perforator vein incompetence, without deep venous insufficiency. Methods This was a retrospective review of prospectively collected data. Twenty-four limbs with both superficial and perforator venous incompetence but no deep venous insufficiency were identified at venous duplex scanning. Air plethysmography (APG) was performed preoperatively, to obtain venous volume (VV), venous filling index (VFI), ejection fraction (EF), and residual volume fraction (RVF) of the affected limb. Saphenous vein stripping from the groin to knee and powered transilluminated phlebectomy for varicosity ablation were performed in all patients. Postoperatively, all patients underwent duplex scanning and APG to determine the status of the perforator veins and hemodynamic improvement from surgery. Results Average patient age was 55.8 years; 62% of patients were women. CVI was class 3 in 4 limbs, class 4 in 12 limbs, and class 5 and class 6 in 4 limbs each. Postoperative duplex scans demonstrated that 71% of previously incompetent perforator vessels were now competent or absent. Significant improvement in all APG values was documented after superficial surgery. VFI improved from 6.0 ± 2.9 preoperatively to 2.2 ± 1.3 after surgery (P < .001); EF improved from 56.3 ± 18 to 62 ± 21 (P = .02); and RVF improved from 40.1 ± 19 to 28.3 ± 18 (P = .009). Mean preoperative symptom score (5.3 ± 1.9) was significantly improved at mean follow-up of 18.3 months (1.4 ± 1.2; P < .001). Conclusion Patients with superficial and perforator vein incompetence and a normal deep venous system experienced significant improvement in APG-measured hemodynamic parameters and clinical symptom score after superficial ablative surgery alone. This suggests that ligation of the perforator veins can be reserved for patients with persistent incompetent perforator vessels, with abnormal hemodynamic parameters or continued symptoms after superficial ablative surgery

Integrating the Humanities with Engineering through a Global Case Study Course

As the world becomes more connected and globalized, the problems that engineers are called upon to solve are increasingly complex and interdependent. Unfortunately, engineering coursework has traditionally focused on abstract and closed-ended problem solving, offering few opportunities for students to develop these skills. In this practice paper, we argue for the importance of integrating the humanities and engineering to understand the multiple and intersecting layers of context in an engineering project. We then describe the Humanities-Informed Engineering Projects course, which we developed to help students acquire this perspective. The course was piloted in Spring 2021 in response to the obstacles to international and community engineering experiences caused by the COVID-19 pandemic. Lastly, we share preliminary assessment data on the development of systems thinking through the course. This pedagogical description and assessment project contributes to the understanding of the development of systems thinking and it also provides empirical evidence about the potential benefits of integrating the humanities and engineering in the classroom

A Multicenter Randomized Controlled Trial Comparing Treatment of Venous Leg Ulcers Using Mechanically Versus Electrically Powered Negative Pressure Wound Therapy

Objective: This study compares two different negative pressure wound therapy (NPWT) modalities in the treatment of venous leg ulcers (VLUs), the ultraportable mechanically powered (MP) Smart Negative Pressure (SNaP®) Wound Care System to the electrically powered (EP) Vacuum-Assisted Closure (V.A.C.®) System

Comparative effectiveness of a bilayered living cellular construct and a porcine collagen wound dressing in the treatment of venous leg ulcers

Using data from a national wound-specific electronic medical record (WoundExpert, Net Health, Pittsburgh, PA), we compared the effectiveness of a bilayered living cellular construct (BLCC) and an acellular porcine small intestine submucosa collagen dressing (SIS) for the treatment of venous leg ulcer. Data from 1,489 patients with 1,801 refractory venous leg ulcers (as defined by failure to have >40% reduction in size in the 4 weeks prior to treatment) with surface areas between 1 and 150 cm2 in size, treated between July 2009 and July 2012 at 158 wound care facilities across the US were analyzed. Patient baseline demographics and wound characteristics were comparable between groups. Kaplan-Meier–derived estimates of wound closure for BLCC (1,451 wounds) was significantly greater (p = 0.01, log-rank test) by weeks 12 (31% vs. 26%), 24 (50% vs. 41%), and 36 (61% vs. 46%), respectively, compared with SIS (350 wounds). BLCC treatment reduced the median time to wound closure by 44%, achieving healing 19 weeks sooner (24 vs. 43 weeks, p = 0.01, log-rank test). Treatment with BLCC increased the probability of healing by 29% compared with porcine SIS dressing (hazard ratio = 1.29 [95% confidence interval 1.06, 1.56], p = 0.01)

Descending thoracic aorta to iliofemoral artery bypass grafting: A role for primary revascularization for aortoiliac occlusive disease?

AbstractPurpose: Bypass grafts that originate from the descending thoracic aorta to the iliac or femoral arteries are well described but are not commonly used as primary procedures, and the long-term results remain unknown. A 15-year experience with 50 descending thoracic aorta to iliofemoral artery bypass grafts for aortoiliac occlusive disease is the basis of this report. Methods: From January 1983 to December 1997, patients who underwent bypass grafting procedures from the descending thoracic aorta to the iliac or femoral arteries were identified. Surgical indications, morbidity and mortality rates, primary and secondary patency rates, limb salvage rates, and survival rates were determined. Results: Fifty descending thoracic aorta to iliofemoral artery bypass grafting procedures were performed—24 (48%) for severe claudication, 22 (44%) for rest pain, and 4 (8%) for ischemic ulceration. A primary procedure was performed in 31 patients (62%) for complete occlusion (21 patients) and severe atherosclerotic disease (10 patients) of the infrarenal aorta. The indications for 19 secondary revascularizations (38%) were prior aortic or extra-anatomic graft failure in 17 cases and aortic graft infection in 2 cases. The follow-up periods ranged from 1 to 150 months (mean, 39 months). The cumulative life-table 5-year primary patency, secondary patency, limb salvage, and survival rates were 79%, 84%, 93%, and 67%, respectively. An improved patency trend was observed for patients who underwent operation for severe claudication as compared with limb-threatening ischemia (92% and 69%; P = .07). However, there was no difference between primary and secondary operations in primary patency rates (81% and 79%; P = NS) or survival rates (72% and 62%; P = NS). Conclusion: Descending thoracic aorta to iliofemoral artery bypass grafting has excellent overall long-term results. These results support its more liberal use for primary revascularization, especially for patients with severe atherosclerotic disease or complete occlusion of the infrarenal aorta. (J Vasc Surg 1999;29:249-58.

Descending thoracic aorta to iliofemoral artery bypass grafting: A role for primary revascularization for aortoiliac occlusive disease?

AbstractPurpose: Bypass grafts that originate from the descending thoracic aorta to the iliac or femoral arteries are well described but are not commonly used as primary procedures, and the long-term results remain unknown. A 15-year experience with 50 descending thoracic aorta to iliofemoral artery bypass grafts for aortoiliac occlusive disease is the basis of this report. Methods: From January 1983 to December 1997, patients who underwent bypass grafting procedures from the descending thoracic aorta to the iliac or femoral arteries were identified. Surgical indications, morbidity and mortality rates, primary and secondary patency rates, limb salvage rates, and survival rates were determined. Results: Fifty descending thoracic aorta to iliofemoral artery bypass grafting procedures were performed—24 (48%) for severe claudication, 22 (44%) for rest pain, and 4 (8%) for ischemic ulceration. A primary procedure was performed in 31 patients (62%) for complete occlusion (21 patients) and severe atherosclerotic disease (10 patients) of the infrarenal aorta. The indications for 19 secondary revascularizations (38%) were prior aortic or extra-anatomic graft failure in 17 cases and aortic graft infection in 2 cases. The follow-up periods ranged from 1 to 150 months (mean, 39 months). The cumulative life-table 5-year primary patency, secondary patency, limb salvage, and survival rates were 79%, 84%, 93%, and 67%, respectively. An improved patency trend was observed for patients who underwent operation for severe claudication as compared with limb-threatening ischemia (92% and 69%; P = .07). However, there was no difference between primary and secondary operations in primary patency rates (81% and 79%; P = NS) or survival rates (72% and 62%; P = NS). Conclusion: Descending thoracic aorta to iliofemoral artery bypass grafting has excellent overall long-term results. These results support its more liberal use for primary revascularization, especially for patients with severe atherosclerotic disease or complete occlusion of the infrarenal aorta. (J Vasc Surg 1999;29:249-58.