A meta-analysis on the effect of proximal landing zone location on stroke and mortality in thoracic endovascular aortic repair.

BACKGROUND: Thoracic endovascular aortic repair (TEVAR) involving the aortic arch may increase the opportunity for stroke owing to disruption of cerebral circulation and embolization. In this study, a systematic meta-analysis was performed to examine the impact of proximal landing zone location on stroke and 30-day mortality after TEVAR. METHODS: MEDLINE and Cochrane Library were searched for all original studies of TEVAR reporting outcomes of stroke or 30-day mortality for at least two adjacent proximal landing zones, based on the Ishimaru classification scheme. Forest plots were created using relative risks (RR) with 95% confidence intervals (CI). An I2 of <40% was regarded as minimal heterogeneity. A P value of <.05 was considered significant. RESULTS: Of the 57 studies examined, a total of 22,244 patients (male 73.1%, aged 71.9 ± 11.5 years) were included in the meta-analysis, with 1693 undergoing TEVAR with proximal landing zone 0, 1931 with zone 1, 5839 with zone 2, and 3089 with zone 3 and beyond. The overall risk of clinically evident stroke was 2.7% for zones ≥3, 6.6% for zone 2, 7.7% for zone 1, and 14.2% for zone 0. More proximal landing zones were associated with higher risks of stroke compared with distal (zone 2 vs ≥3: RR, 2.14; 95% CI, 1.43-3.20; P = .0002; I2 = 56%; zone 1 vs 2: RR, 1.48; 95% CI, 1.20-1.82; P = .0002; I2 = 0%; zone 0 vs 1: RR, 1.85; 95% CI, 1.52-2.24; P < .00001; I2 = 0%). Mortality at 30 days was 2.9% for zones ≥3, 2.4% for zone 2, 3.7% for zone 1, and 9.3% for zone 0. Zone 0 was associated with higher mortality compared with zone 1 (RR, 2.30; 95% CI, 1.75-3.03; P < .00001; I2 = 0%). No significant differences were found in 30-day mortality between zones 1 and 2 (P = .13) and between zone 2 and zones ≥3 (P = .87). CONCLUSIONS: The risk of stroke from TEVAR is lowest in zone 3 and beyond, increasing significantly as the landing zone is moved proximally. Furthermore, perioperative mortality is increased with zone 0 compared with zone 1. Therefore, risk of stent grafting in the proximal arch should be weighed against alternative surgical or nonoperative options. It is anticipated that the risk of stroke will improve with further development of stent graft technology and implantation technique.

Analysis of a Novel Inpatient Acute Limb Ischemia Alert System.

OBJECTIVES: Acute limb ischemia (ALI) is a surgical emergency that generally develops in the outpatient setting. Hospitalized patients are also at risk for acute limb ischemia, but their presentation may be atypical or altered by medical therapy. Our institution developed an alert system to facilitate the prompt recognition and treatment of ALI that occurs in the inpatient population. We aimed to evaluate the usage of the system after the first 2 years of operation. METHODS: All ALI alerts from October 2017 to December 2019 were collected from paging records and analyzed for location, timing, and the need for intervention. Alerts undergoing vascular intervention were classified as urgent (within 8 hours) or delayed (after 8 hr). Time and location data were evaluated to determine patterns of usage and true-positive rate of the system. RESULTS: From October 2017 to December 2019, there were 237 ALI alerts obtained from paging records containing time and location information for the alert. More alerts originated from ICUs relative to non-ICU floors (68% vs. 33%, P< 0.001), however a greater proportion of non-ICU floor alerts required intervention compared to ICU alerts (32.0% vs. 5.1%, P < .0001). The highest number of ALI alerts were from the Medical ICU (MRICU) (45.9%) and medical/surgical floors (33.3%), followed by Surgical ICU (20.2%). Alerts were more common within 3 hr of morning and evening nursing shift changes (47.3%, P < 0.001). From the 237 total alerts, the patient was able to be identified retrospectively in 186 cases, and of these 27 resulted in operative interventions (14.5%, positive predictive value), with 11 patients (40.7%) requiring urgent intervention with a median time to intervention of 3.5 hr (range 2.2-4.8), and 16 (59%) alerts undergoing a delayed intervention at a mean of 3 days (range 2-4). A total of 73 (39.2%) alert patients died during their admission, of which 65 (89.0%) were in an ICU, and no deaths were directly related to ALI. The median time to death was 2 days (range 0-95 days), and in 22 cases death occurred <24 hr from time of alert. CONCLUSION: Our novel hospital-wide ALI alert system demonstrates a 14.5% positive predictive value for ischemia that resulted in an intervention. Alerts were more likely to originate from the ICU setting and during nursing shift changes. Alerts originating from non-ICU floors were 5 times more likely to undergo surgical intervention for ALI. Further analysis is required to assess the effect of this system on patient safety, outcome, and allocation of institutional resources.

The Application of Virtual Reality in Patient Education.

BACKGROUND: Virtual reality (VR) provides an immersive image-viewing experience that has recently been expanding in use in clinical medicine. We developed a three-dimensional (3D) model of an abdominal aortic aneurysm (AAA) for patients with a diagnosis of an AAA to view in VR to assess the use of VR in patient education. METHODS: This was a cross-sectional study using an educational intervention. A standardized 3D model of an AAA was generated from a computed tomography scan and uploaded onto a 3D image-hosting website. Patients with an AAA who participated in the study wore a Google Cardboard VR headset, with a mobile device displaying the digital 3D AAA image in VR. Patients completed a survey afterward for assessing satisfaction with VR on a 5-point agreement Likert scale. RESULTS: Between September 2017 and January 2018, 19 patients participated in our study (90% participation rate). Most participants had no prior experience with VR (n = 15; 79%), and the mean age was 69 ± 8 years. Seventeen (89%) participants agreed or strongly agreed that they felt better informed about their health status after using VR and would like to see VR used more in their health care, while sixteen (84%) agreed or strongly agreed that they felt more engaged in their health care because of using VR. Almost all participants felt comfortable using VR (n = 17; 90%) and enjoyed using the technology (n = 16; 84%). CONCLUSIONS: VR proved to be an engaging learning tool that patients perceived as beneficial in understanding their health status. Further efforts to investigate the role of VR in education and health care should be explored.

Previous hemodialysis access improves functional outcomes of the proximal radial artery fistula in males.

BACKGROUND: The proximal radial artery fistula (PRA) has been established as an early viable surgical option for arteriovenous fistula creation. The overall assisted primary patency reported in the literature approaches 100% at 1 year. We hypothesize that this excellent patency does not represent a functional result when seen in light of successful cannulation and fistula utilization. METHODS: We retrospectively queried our Veterans Administration Hospital operative database to identify 284 male patients who had 571 access procedures performed by a senior vascular surgeon attending (R.K.D.) from January 1, 2003, to December 31, 2008. Operative details, patient comorbidities, fistula maturation time (time to first cannulation), functional patency (date of access to abandonment, revision to another fistula type, conversion to a prosthetic graft, thrombosis of the fistula, conversion to peritoneal dialysis, renal transplant, or patient death), and total duration (creation of the fistula to the end of its functional patency) were collected and analyzed. RESULTS: A total of 144 PRAs were placed during the study period. In all, 87 patients underwent primary proximal radial artery fistula (P-PRA) placement in a limb without previous access; 57 patients had a secondary proximal radial artery fistula (S-PRA) after a failed previous fistula or graft in the same limb. There were no differences between the 2 groups in terms of age, comorbidities, and operative details. A total of 91 patients (63.2%) were receiving hemodialysis at the time of P-PRA or S-PRA placement. Outcomes of P-PRA and S-PRA populations on hemodialysis were examined. There was increased cannulation success (33% vs. 55%; P = 0.00354, Fisher's exact test), functional patency (755.2 ± 661.2 days vs. 405.4 ± 531.9 days; P = 0.0220, Wilcoxon two-sample test), and total duration (859.5 ± 650.7 days vs. 516.8 ± 547.2 days; P = 0.0361, Wilcoxon two-sample test) of S-PRA over P-PRA. There was no difference in endovascular interventions between the 2 groups (1.6 ± 1.0 interventions per access versus 1.1 ± 0.7 interventions per access; P = 0.2109, Wilcoxon two-sample test). Subgroup analysis (analysis of variance) of the S-PRA group indicated that a patent but failing previous access in the same arm was not superior in terms of successful cannulation, functional patency, or total duration when compared with a thrombosed previous access. CONCLUSIONS: The PRA remains a viable first access procedure undertaken at our institution. Compared with the reported 12-month assisted primary patency of this fistula type, we found a small percentage of PRAs actually being accessed for successful hemodialysis treatment. The S-PRA appears to have a significantly higher successful cannulation rate, functional patency, and total duration time when compared with the P-PRA in patients receiving hemodialysis treatments. The mechanism of these improved outcomes is not known; considering patency or thrombosis of a previous access in the S-PRA group did not predict future access success in the same extremity.

Low incidence of pulmonary embolism associated with upper-extremity deep venous thrombosis.

BACKGROUND: Most recent Chest 2008 guidelines counsel at least 3 months of anticoagulation for acute upper-extremity deep venous thrombosis (UEDVT). These guidelines are inconsistently followed, perhaps owing to relatively limited information regarding clinical outcomes among patients with UEDVT. Our institution maintains an UEDVT registry of consecutively encountered patients with sonographically confirmed UEDVT. We analyzed patient characteristics, treatment, and outcomes among these patients. METHODS: Between April 2005 and November 2008, 300 consecutively encountered peripheral vascular laboratory patients with UEDVTs were identified. Data on UEDVT sonographic characteristics, patient demographics, anticoagulation treatment, pulmonary embolism (PE) incidence and diagnostic modality, hemorrhagic complications, and mortality were then extracted. RESULTS: Among the 300 patients, there was deep venous obstruction in the distal innominate (n = 69), internal jugular (n = 146), subclavian (n = 161), axillary (n = 107), and brachial (n = 91) veins. Two hundred forty-six patients (82%) had UEDVTs identified as clearly acute or acute on chronic, based on sonographic appearance. Most patients with UEDVTs were symptomatic (n = 265, 88%). One hundred six patients had documented malignancy (35%), 92 were postoperative or trauma patients (31%), and 76 patients were obese (body mass index: >30, 25%). Additionally, 240 patients had associated or previous indwelling central venous lines or leads (80%). One hundred twenty-eight patients (43%) were initially anticoagulated with heparin, whereas 121 of these patients were converted to warfarin therapy (40%) for variable lengths of time. One hundred sixty-seven patients were not treated with anticoagulation (56%), of whom 16 had documented contraindication to anticoagulation. Although the anticoagulated subset of patients tended to be younger, the decision to anticoagulate patients correlated significantly with the sonographically documented acute nature of the deep venous thrombosis, and its extent. Six patients (2%) suffered PE in association with their UEDVT diagnosis. There was no PE-related mortality. However, among anticoagulated UEDVT patients, there were four patients who suffered intracranial hemorrhage resulting in three deaths, and an additional three patients who required rehospitalization for upper gastrointestinal (n = 2) or stomal (n = 1) hemorrhage. CONCLUSIONS: Anticoagulation therapy is inconsistently used to treat UEDVT and most often used for patients with multiple vein segments involved and with sonographically acute UEDVT components. However, regardless of the decision to anticoagulate, the incidence of PE attributable to UEDVT is small (2%), regardless of treatment with anticoagulation. Given the observed mortality associated with anticoagulation in this fragile patient cohort, the risk-benefit analysis for anticoagulation does not favor routine anticoagulation among these patients.

Upper extremity deep venous thrombosis: reassessing the risk for subsequent pulmonary embolism.

BACKGROUND: Although the incidence of upper extremity deep venous thrombosis (UEDVT) diagnoses has increased, anticoagulation therapy for UEDVT remains inconsistent and of variable duration. This study sought to analyze our institution's current treatment practices for UEDVT and assess the risk for subsequent pulmonary embolism (PE). METHODS: Between April 2005 and July 2007, 200 consecutively encountered patients with UEDVTs were identified in the Peripheral Vascular Laboratory. Then, UEDVT location and sonographic characteristics, patient demographics, anticoagulation treatment, and PE incidence and mortality were examined. RESULTS: Among the 200 patients with UEDVT, 156 (78%) had UEDVTs identified as clearly acute or acute on chronic, based on sonographic appearance. In all, 85% of the patients were symptomatic (n = 171). Among the patients, 71 (36%) had documented malignancy, 58 (29%) were postoperative or suffering from trauma, and 52 (26%) were obese (body mass index: >30). In addition, 153 (76%) had associated current or previous indwelling lines or leads. A total of 73 patients (36%) were put on anticoagulation therapy for variable periods. Younger age of the patient, duplex evidence of an acute deep venous thrombosis, and involvement of multiple named upper extremity venous segments were independent predictors of the decision to initiate anticoagulation therapy for patients with UEDVT. Two patients (1%) suffered PE, most likely the consequence of their UEDVTs. An additional two patients with UEDVT treated with coumadin died months after hospital discharge from intracranial bleedings after minor falls. CONCLUSION: Currently, the clinical decision to initiate anticoagulation therapy for patients with UEDVT is most associated with the documented acute nature of the deep venous thrombosis by duplex ultrasonography, involvement of multiple venous segments, and younger age of the patient. The incidence of PE attributable to previously documented UEDVT is very small (1%), regardless of anticoagulant therapy. Anticoagulation therapy for UEDVT is most likely to be best suited to address the symptoms of UEDVT; its proposed use to decrease the very small risk of PE may be rarely indicated, and must be carefully weighed with the risks associated with therapeutic anticoagulation in this patient population.

Saphenous vein graft aneurysm with graft-enteric fistula after renal artery bypass.

A 65-year-old female presented with upper gastrointestinal hemorrhage thirty years following an aorta-to-right renal artery bypass constructed with saphenous vein. Upper endoscopy demonstrated a duodenal ulcer, and a CAT scan demonstrated aneurysmal degeneration of her renal artery bypass with duodenal impingement. Laparotomy demonstrated erosion of the aneurysm through the posterior wall of the duodenum; extra-anatomic renovascular reconstruction and primary duodenal repair was performed. Although aneurysmal degeneration of intraabdominal saphenous vein grafts is well described and rupture likewise reported, this report represents the first description of an intraabdominal autogenous vein graft aneurysm presenting with gastrointestinal erosion and fistula.

Analysis of noncatheter-associated upper extremity deep venous thrombosis from the RIETE registry.

OBJECTIVE: We sought to determine the risk factors for subsequent bleeding and recurrent venous thromboembolism (VTE) events following isolated noncatheter-associated upper extremity deep venous thrombosis (non-CA-UEDVT) to better inform future treatment decisions for this group of patients. METHODS: The RIETE registry (Registro Informatizado de Enfermedad TromboEmbólica [Computerized Registry of Patients with Venous Thromboembolism]) is a prospective international registry of patients with objectively confirmed symptomatic VTE. Patients with a symptomatic, isolated, proximal UEDVT from March 2001 through March 2015 were analyzed. Any patient with an indwelling catheter or pacemaker lead at the DVT site and at the time of thrombosis was considered to have a CA-UEDVT and was excluded. Patient and treatment characteristics such as age, gender, comorbidities, VTE risk factors, treatment drug, and duration were collected. Outcomes examined included recurrent DVT, subsequent pulmonary embolism (PE), and hemorrhage. Multivariate analysis was performed using stepwise logistic regression. RESULTS: Of the 1100 patients who met the study criteria, 580 (53%) were male. The mean age of the patients was 50 ± 20 years, and overall patient survival at 1 year was 85%. Recurrent VTE occurred in 59 patients (5.4%). Of these, 46 patients (4%) had recurrent DVT, 10 (0.9%) had a PE following UEDVT diagnosis, and 3 (0.3%) had both. PE was fatal in three patients (0.3%). Bleeding occurred in 50 patients (4.5%), major bleeding in 19 patients (1.7%), and fatal bleeding in 6 patients (0.5%). On multivariate analysis, malignant disease was associated with VTE recurrence (odds ratio [OR], 2.00; 95% confidence interval [CI], 1.04-3.45; P < .04), whereas hemorrhage was associated with age (OR, 1.03; 95% CI, 1.01-1.05; P = .002) and malignant disease (OR, 2.53; 95% CI, 1.34-4.76; P < .005). Hemorrhage and recurrent VTE were also significantly associated (OR, 2.79; 95% CI, 1.16-6.76; P < .03). CONCLUSIONS: PE following non-CA-UEDVT is rare. Malignant disease was associated with VTE recurrence. Age and malignant disease were associated with hemorrhage, and VTE recurrence was associated with hemorrhage. Further prospective studies should be undertaken to best determine length of anticoagulation treatment for the varied populations of patients with UEDVT.

Intrathymic islet transplantation in the canine: I. Histological and functional evidence of autologous intrathymic islet engraftment and survival in pancreatectomized recipients.

BACKGROUND: Although an attractive alternative to daily insulin therapy, allogeneic pancreatic islet transplantation has yielded suboptimal results in clinical trials, in contrast to islet allotransplantation in animal models, which have demonstrated consistent success. The successful transplantation of isolated islets to the thymus, with a single concomitant dose of antilymphocyte serum, has been demonstrated in rodents, and more significantly, such intrathymic islet allografts have been shown to induce recipient tolerance toward subsequent extrathymic donor strain islet allografts. Intrathymic islet autotransplantation has been pursued, as a prelude to studies of allogeneic IT islet transplantation and tolerance induction, in canine, porcine, and non-human primate models, to assess the large animal thymus as a site capable of supporting a viable islet graft. However, little functional or histological evidence has established definitive survival of islets transplanted within the thymus of a phylogenetically advanced species, which may be requisite to tolerance induction. This study describes the successful intrathymic autotransplantation of isolated islets using a canine model. METHODS: Purpose-bred juvenile dogs, aged 4-6 months, underwent partial (n=4), or total pancreatectomy (n=11), and transplantation of autologous islets. The pancreas (or pancreatic limb) was distended with collagenase solution, and digested using a modification of the semiautomated system of Ricordi. Islets were purified by discontinuous gradient centrifugation, using Euroficoll (ficoll in Euro-Collin's kidney preservation solution). Partially pancreatectomized canines underwent IT transplantation of purified autologous islets (8000+/-4000 IEs), and were killed 8 weeks posttransplant. Totally pancreatectomized canines underwent transplantation of autologous islets to the liver (via portal vein embolization, n=5, IPO group) or the thymus (via direct IT injection, n=6, IT group), and were serially evaluated for a period of 8 weeks posttransplant to assess fasting blood glucose (FBG), serum insulin (SI) levels, and i.v. glucose tolerance (IVGTTs). K values (defined as the %-decrease/minute of the log(e) of blood glucose values) were calculated from IVGTT results. RESULTS: After autotransplantation in this cohort of animals, five of five IPO, and three of six IT islet recipients, remained normoglycemic (mean FBG< or =250 mg%) immediately posttransplant, and all recipients exhibited significantly elevated SI levels compared to apancreatic controls (n=10, followed 72 hr postpancreatectomy). Normal k values (=-1.1) were observed in two of five IPO, and in one of six IT recipients, 8 weeks after transplantation, and thymic tissue insulin content was increased compared to non-islet-bearing thymi (93.7+/-48.6 ng/g tissue vs. 0.7+/-0.4 ng/g tissue). At 8 weeks posttransplantation thymi from both partially and totally pancreatectomized animals were resected and processed for histological examination. Microscopic analysis of islet-bearing thymi revealed positive staining for islet-specific hormones (insulin and glucagon) within all IT recipients., Identification of islets within thymi of hyperglycemic IT recipients was problematic as islet beta cells were highly degranulated as a result of the recipients glycemic state. CONCLUSIONS: These results indicate that autologous islets, transplanted to the canine thymus, engraft, function, and survive for up to 8 weeks after islet autotransplantation to the canine thymus and establish the feasibility of intrathymic islet transplantation in a phylogenetically advanced animal model. The ability of islets to survive within the thymic environment for a period of at least 8 weeks after transplantation suggests that the successful induction of specific unresponsiveness secondary to intrathymic transplantation will not be impaired or limited by the inability of a viable islet mass to survive within the thymus for a sufficient period.

DVT surveillance program in the ICU: analysis of cost-effectiveness.

BACKGROUND: Venous Thrombo-embolism (VTE--Deep venous thrombosis (DVT) and/or pulmonary embolism (PE)--in traumatized patients causes significant morbidity and mortality. The current study evaluates the effectiveness of DVT surveillance in reducing PE, and performs a cost-effectiveness analysis. METHODS: All traumatized patients admitted to the adult ICU underwent twice weekly DVT surveillance by bilateral lower extremity venous Duplex examination (48-month surveillance period--SP). The rates of DVT and PE were recorded and compared to the rates observed in the 36-month pre-surveillance period (PSP). All patients in both periods received mechanical and pharmacologic prophylaxis unless contraindicated. Total costs--diagnostic, therapeutic and surveillance--for both periods were recorded and the incremental cost for each Quality Adjusted Life Year (QALY) gained was calculated. RESULTS: 4234 patients were eligible (PSP--1422 and SP--2812). Rate of DVT in SP (2.8%) was significantly higher than in PSP (1.3%) - p<0.05, and rate of PE in SP (0.7%) was significantly lower than that in PSP (1.5%) - p<0.05. Logistic regression demonstrated that surveillance was an independent predictor of increased DVT detection (OR: 2.53 - CI: 1.462-4.378) and decreased PE incidence (OR: 0.487 - CI: 0.262-0.904). The incremental cost was $509,091/life saved in the base case, translating to $29,102/QALY gained. A sensitivity analysis over four of the parameters used in the model indicated that the incremental cost ranged from $18,661 to $48,821/QALY gained. CONCLUSIONS: Surveillance of traumatized ICU patients increases DVT detection and reduces PE incidence. Costs in terms of QALY gained compares favorably with other interventions accepted by society.

Feasibility of endovascular repair in penetrating axillosubclavian injuries: a retrospective review.

BACKGROUND: Penetrating injuries to the axillary and subclavian vessels are a source of significant morbidity and mortality. Although the endovascular repair of such injuries has been increasingly described, an algorithm for endovascular versus conventional surgical repair has yet to be clearly defined. On the basis of institutional endovascular experience treating vascular injuries in other anatomic locations, we defined an algorithm for the management of axillosubclavian vascular injuries. Subsequently, a near decade long experience with the management of axillosubclavian vascular injuries was retrospectively analyzed, so as to more accurately assess the true feasibility of endovascular treatment in these patients. METHODS: We defined a management algorithm that included (1) indications, (2) relative contraindications, and (3) strict contraindications for the endovascular repair of axillosubclavian vascular injuries. Anatomic indications for endovascular repair were restricted to relatively limited axillosubclavian injuries (pseudoaneurysms, arteriovenous fistulas, first-order branch vessel injuries, intimal flaps, and focal lacerations). Relative contraindications for endovascular repair included injury to the axillary artery's third portion, substantial venous injury (eg, transection), refractory hypotension, and upper extremity compartment syndrome with neurovascular compression. Strict contraindications to endovascular repair included long segmental injuries, injuries without sufficient proximal or distal vascular fixation points, and subtotal/total arterial transection. Within the context of these definitions, we retrospectively reviewed 46 noniatrogenic subclavian and axillary vascular injuries in 45 patients identified by a prospectively maintained computer registry during a 9-year period. Presentations were reviewed concurrently by two endovascular surgeons, and potential candidates for endovascular management were defined. RESULTS: Among 46 total case presentations and among the 40 patients who maintained vital signs on presentation, 17 were potentially treatable with endovascular therapy. Among the cohort of 40 presentations, the most common contraindications to endovascular therapy were hemodynamic instability (n = 10), vessel transection (n = 7), and no proximal vascular fixation site (n = 3). CONCLUSIONS: Despite growing enthusiasm for endovascular repair of injuries to the axillary and subclavian vessels, realistic clinical presentation and anatomic locations restrict the broad application of this technique at present. In our experience, less than but approaching 50% of all injuries encountered could be addressed with an endovascular approach. This percentage will increase during the upcoming decades if the endovascular technologies available in hybrid endovascular operating rooms uniformly improve.