Intraoperative Pedal Pressure Changes Offers Another Quantitative Assessment for Revascularization

BACKGROUND

Lower extremity angiography is one of the most prevalent vascular procedures performed, generally via the contralateral common femoral artery. The use of retrograde pedal artery access to perform angiography has long been reserved as a "bail-out" technique to help cross chronic total occlusions that were not amenable from an antegrade approach. Recently, there have been reports and discussions involving increased utilization of pedal access for primary revascularization. The purpose of this study is to describe the outcomes of pedal access as a primary approach and to propose a novel evaluation of distal perfusion changes associated with interventions using direct pressure measurements.

METHODS

A retrospective observational study evaluating all patients who underwent lower extremity angiography via retrograde pedal access between December 1, 2020, and June 30, 2021, within a single health-care system spanning 3 hospitals was performed. Demographics, comorbidities, procedural indications, and details were all recorded. Hemodynamic measurements were obtained and recorded upon initial pedal access and post intervention with a pressure transducer connected directly to the access sheath. Outcomes were analyzed with paired t-test.

RESULTS

Twenty-eight angiograms using primary pedal access for endovascular intervention were performed during the study period. Most patients were African American (75%) females (57.1%) with hypertension (89.3%), hyperlipidemia (78.6%), diabetes (85.7%), coronary artery disease (64.3%), and current tobacco users (57.1%). The most prevalent indication for angiography was nonhealing wounds (67.9%). Pedal access was mostly achieved via the anterior tibial artery (79%). Sixty-three vessels were treated during the 28 angiograms (averaging 2.3 vessels per angiogram), most commonly the superficial femoral (27%), anterior tibial (25%), and popliteal (22%) arteries. Balloon angioplasty with or without stenting (98.5%) was predominately performed with an overall technical success rate of 94%. The mean preintervention and postintervention pressures were 36.5 mm Hg (standard deviation [SD] 25.7) and 83.4 mm Hg (SD 19.5), respectively. The mean change in pressure after intervention was 46.9 mm Hg (SD 23.3) (Table 3). There was a statistically significant difference detected between preintervention and postintervention pressure (P < 0.001) (Figure 1). There were no major amputations or adverse cardiovascular events at a mean first follow-up duration of 89 days. Six of the total 28 patients (21.4%) underwent repeat endovascular intervention on the ipsilateral extremity within a median of 45 (interquartile range 22.5-62.3) days.

CONCLUSIONS

Primary pedal access is a viable option for performing lower extremity angiographic interventions. A significant increase in pedal artery pressure can be observed after angiographic intervention from retrograde pedal artery access. Further studies are necessary to define the clinical prognostic importance of these findings in relation to wound healing rates.

Transcarotid Arterial Revascularization Adoption Should not Be Hindered by a Concern for a Long Learning Curve

BACKGROUND

Transcarotid arterial revascularization (TCAR) offers a novel technique for carotid artery stenting (CAS) that provides flow reversal in the carotid artery and avoids aortic arch manipulation, thus, potentially lowering ipsilateral and contralateral periprocedural stroke rates. As a new technology, adoption may be limited by concern for learning a new technique. This study seeks to examine the number of cases needed for a surgeon to reach technical proficiency.

METHODS

Retrospective analysis was performed using a prospectively collected database of all TCAR procedures performed in a tertiary health care system between 2016 and 2020. Patient demographics and anatomic characteristics were collected. Intraoperative variables and perioperative outcomes were examined. These variables were collated into groups for the first 4 procedures, procedures 5-8, and after 8. Independent Samples t test, 1-way ANOVA, and logarithmic regression were used to statistically analyze the data.

RESULTS

One-hundred and eighty-seven TCARs were performed by 14 surgeons. One hundred and twenty-two (65%) were male, 59 (32%) were older than 75 years, and 83 (44%) were symptomatic. The most common indications were high-lesions in 87 patients (47%) and recurrent stenosis after CEA in 37 patients (20%). Significant differences were found between the first and second groups of 4 cases when comparing mean operative time (71 vs. 58 min; P = 0.001) and flow reversal time (10.8 vs. 7.9 min; P= 0.004). similar significant differences were found between the first and third groups of 4 cases but not between the second and third groups. There was a reduction in contrast usage and fluoroscopy time after the first 4 cases, however, this did not reach statistical significance. There was no ipsilateral perioperative strokes. One patient had a contralateral stroke on postoperative day 2 due to intracranial atherosclerosis, and there was one perioperative mortality that occurred on postoperative day 3 after discharge.

CONCLUSIONS

Procedural and flow reversal times significantly shorten after 4 TCAR procedures are performed. Other metrics, such as fluoroscopy time and contrast usage, are also decreased. Complications, in general, are minimal. Proficiency in TCAR, as measured by these metrics, is met after performing only 4 procedures.

Results of Obturator Foramen Bypass in Patients with Groin Infection and Arterial Involvement

BACKGROUND

Arterial bypass tunneling via the obturator foramen (OFB) can be performed to circumvent groin infections during lower extremity revascularization. The objective of this study is to report safety and efficacy outcomes of OFB in the setting of infected femoral pseudoaneurysms and infected prosthetic femoral bypass grafts.

METHODS

A multihospital, single-entity healthcare system retrospective review was conducted for all patients who underwent OFB between January 2014 through June 2020. Any patient >18 years of age who underwent OFB in the setting of groin infection with a minimum of 30 days follow-up was included in the trial. Demographic, operative, and clinical characteristics of patients were gathered during chart review. Statistical analysis was performed using Microsoft Excel and R studio.

RESULTS

Seventeen patients underwent OFB during the defined time-period. Demographic data are presented in the first table (Demographic Characteristics). Mean American Society of Anesthesiologists score was 3.25. Mean estimated blood loss was 500 mL. Mean operative time was 307 min. Mean follow-up time was 8.5 months (range 0-35 months). In total, 41.2% patients underwent fluoroscopic-guided tunneling, and, when compared to blind tunneling, showed no difference in intraoperative complications or operative time (P value 0.3). In total, 52.9% of patients required ICU admission resulting in a mean number of 0.8 ICU days. The overall mean length of stay was 16.8 days. Two major amputations were reported during follow-up. Patient mortality within 30 days was 0%. Primary patency within 30 days was 100%. Intravenous drug use was not associated with an increased number of subsequent groin wound procedures (P value 0.3). Intravenous drug use was not associated with concomitant methicillin-resistant Staphylococcus aureus infection (P value 0.3).

CONCLUSION

OFB is a safe and effective surgical option in patients who are unable to undergo anatomic tunneling during lower extremity bypass. OFB is associated with favorable rates of primary patency and amputation-free survival at midterm follow-up.

Optimization of factors for the prevention of spinal cord ischemia in thoracic endovascular aortic repair

OBJECTIVES

Spinal cord ischemia following thoracic endovascular aortic repair (TEVAR) is a devastating complication. This study seeks to demonstrate how a standardized protocol to prevent spinal cord ischemia affects incidence in patients undergoing TEVAR.

METHODS

Using CPT codes 33880 and 33881, all TEVAR procedures performed at a single tertiary care center from January 2017 to December 2018 were examined. Patients who had concomitant ascending aortic repairs or a TEVAR for traumatic indications were excluded from analysis, leaving 130 TEVAR procedures. Comorbid conditions, procedural characteristics, extent of coverage, peri-procedural management strategies, and post-operative outcomes were collected and analyzed retrospectively.

RESULTS

One hundred thirty patients undergoing TEVAR were examined for four perioperative variables: postoperative hemoglobin greater than 10 g/dL, subclavian revascularization, preoperative spinal drain placement, and somatosensory evoked potential monitoring (SSEP). All conditions were met in 46.2% (60/130) of procedures; 37.8% (28/74) in emergent/urgent cases and 61.5% (32/52) in elective cases. Of patients who required subclavian coverage, 87.1% (54/62) underwent subclavian revascularization; 70.8% (92/130) of patients received spinal drains preoperatively; 68.5% (89/130) of patients had SSEP monitoring; 73.8% (93/130) of patients obtained a postoperative hemoglobin of >10 g/dL. Out of all patients, two (1.5%) developed spinal cord ischemia.

CONCLUSION

Incidence of spinal cord ischemia in our cohort was low at 1.5% (2/130). Individual and bundled interventions for the prevention of spinal cord ischemia were unable to demonstrate a statistically significant effect given the low rate. Nonetheless, we advocate for a proactive approach for the prevention of spinal cord ischemia given our experience in this complex population.

Systematic review and meta-analysis of endovascular interventions for Stanford type A aortic dissection

OBJECTIVE

The standard surgical approach to Stanford type A aortic dissection is open repair. However, up to one in four patients will be declined surgery because of prohibitive risk. Patients who are treated nonoperatively have an unacceptably high mortality. Endovascular repair of the ascending aorta is emerging as an alternative treatment for a select group of patients. The reported rates of technical success, mortality, stroke, and reintervention have varied. The objective of the study was to systematically report outcomes for acute type A dissections repaired using an endovascular approach.

METHODS

The systematic review and meta-analysis was conducted in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. We performed online literature database searches through April 2020. The demographic and procedural characteristics of the individual studies were tabulated. Data on technical success, short-term mortality, stroke, and reintervention were extracted and underwent meta-analysis using a random effects model.

RESULTS

Fourteen studies with 80 cases of aortic dissection (55 acute and 25 subacute) were included in the final analysis. A wide variation was found in technique and device design across the studies. The outcomes rates were estimated at 17% (95% confidence interval [CI], 10%-26%) for mortality, 15% (95% CI, 8%-23%) for technical failure, 11% (95% CI, 6%-19%) for stroke and 18% (95% CI, 9%-31%) for reintervention. The mean Downs and Black quality assessment score was 13.9 ± 3.2.

CONCLUSION

The technique for endovascular repair of type A aortic dissection is feasible and reproducible. The results of our meta-analysis demonstrate an acceptable safety profile for inoperable patients who otherwise would have an extremely poor prognosis. Data from clinical trials are required before the technique can be introduced into routine clinical practice.

Transcarotid Endovascular Repair of Extracranial Internal Carotid Artery Aneurysms Using Flow Reversal for Distal Embolic Protection

Extracranial carotid artery aneurysms (ECAAs) have a low incidence between 0.4% and 4% of all peripheral artery aneurysms and involving 0.1-2% of all carotid artery procedures. Some form of repair is generally warranted as nonoperative management has shown mortality as high as 71%. However, to date a standard method for ECAA repair has not been suggested. Generally, open surgical repair is the preferred technique; however, it has its own limitations and risks. Recently, endovascular approach is increasingly being used not only for the elective repair of unruptured ECAA but also for the management of ruptured ECAA. Herein we present 3 cases of distal extracranial internal carotid artery aneurysms treated with placement of stent grafts.

The role of selective stenting for superior mesenteric artery scallops during fenestrated endovascular aneurysm repair

OBJECTIVE

Stenting of small fenestrations of the Zenith fenestrated endograft (ZFEN; Cook Medical, Bloomington, Ind) is necessary during fenestrated endovascular aneurysm repair (FEVAR) of complex abdominal aortic aneurysms to avoid malalignment. However, stenting of superior mesenteric artery (SMA) scallops of ZFEN devices is optional according to the instructions for use. The objective of this study was to assess the early and midterm outcomes of selective use of stents in SMA scallops of ZFEN during FEVAR procedures.

METHODS

This study is a single-institution retrospective review of prospectively enrolled patients treated at the University of North Carolina at Chapel Hill between July 2010 and August 2014. Only patients with SMA scallops were included for analysis. We compared results between patients grouped as stented or unstented SMA scallops. The scallops were stented when one or more of the following criteria were present: misalignment of scallop determined by balloon testing intraoperatively; configuration consisting of an SMA scallop and a single renal fenestration or stent; and pre-existing stenosis in the vessel adjacent to the graft scallop. The study was approved by the local Institutional Review Board. Primary outcomes addressed were mortality, vessel patency, early and late complications, and reintervention rates. Baseline characteristics of the patients and procedure data were also described.

RESULTS

During the 48-month study period, 61 patients were treated for complex abdominal aortic aneurysms at the University of North Carolina with a mean age of 73 years, and 74.3% of patients were male. Thirty-nine of 61 patients (63.9%) had a device design with an SMA scallop and were included for analysis. Eleven of 39 patients (28%) had the SMA primarily stented and 28 (72%) were unstented. There was only one death (2.5%) during the 30-day postoperative period, with 100% technical success and branch patency. In the unstented group, there were three SMA complications during follow-up, two requiring reintervention; however, there were no associated deaths. Among the stented group, there was one branch-related complication that occurred during the procedure but no stent stenosis or occlusion during the long-term follow-up. During the mean follow-up period of 21.7 months, no SMA stent thrombosis occurred. There was no statistical difference in outcomes between groups.

CONCLUSIONS

Single-wide SMA scallops of ZFEN during FEVAR procedures may be selectively stented using specific criteria and rigorous follow-up, without compromising the safety and efficacy of the SMA.

Performance of acoustic radiation force impulse ultrasound imaging for carotid plaque characterization with histologic validation

OBJECTIVE

Stroke is commonly caused by thromboembolic events originating from ruptured carotid plaque with vulnerable composition. This study assessed the performance of acoustic radiation force impulse (ARFI) imaging, a noninvasive ultrasound elasticity imaging method, for delineating the composition of human carotid plaque in vivo with histologic validation.

METHODS

Carotid ARFI images were captured before surgery in 25 patients undergoing clinically indicated carotid endarterectomy. The surgical specimens were histologically processed with sectioning matched to the ultrasound imaging plane. Three radiologists, blinded to histology, evaluated parametric images of ARFI-induced peak displacement to identify plaque features such as necrotic core (NC), intraplaque hemorrhage (IPH), collagen (COL), calcium (CAL), and fibrous cap (FC) thickness. Reader performance was measured against the histologic standard using receiver operating characteristic curve analysis, linear regression, Spearman correlation (ρ), and Bland-Altman analysis.

RESULTS

ARFI peak displacement was two-to-four-times larger in regions of NC and IPH relative to regions of COL or CAL. Readers detected soft plaque features (NC/IPH) with a median area under the curve of 0.887 (range, 0.867-0.924) and stiff plaque features (COL/CAL) with median area under the curve of 0.859 (range, 0.771-0.929). FC thickness measurements of two of the three readers correlated with histology (reader 1: R² = 0.64, ρ = 0.81; reader 2: R² = 0.89, ρ = 0.75).

CONCLUSIONS

This study suggests that ARFI is capable of distinguishing soft from stiff atherosclerotic plaque components and delineating FC thickness.

Better survival for African and Hispanic/Latino Americans after infrainguinal revascularization in the Society for Vascular Surgery Vascular Quality Initiative

OBJECTIVE

Inferior survival outcomes have historically been reported for African Americans with cardiovascular disease, and poorer outcomes have been presumed for peripheral arterial disease (PAD) as well. The current study evaluates the effect of race and ethnicity on survival of patients undergoing open or endovascular interventions for lower extremity PAD.

METHODS

Data of patients from the Society for Vascular Surgery Vascular Quality Initiative database were obtained for patients undergoing open infrainguinal (INFRA) or suprainguinal (SUPRA) bypass, peripheral vascular intervention (PVI), and amputation (AMP). Patients were further stratified as suprainguinal (SupraPVI) if any of the first three interventions listed included the aorta or iliac vessels or infrainguinal (InfraPVI) if not. The primary outcome was the patient's death (overall mortality) as recorded in the database or determined by cross-reference with the Social Security Death Index (SSDI). The secondary outcome consisted of perioperative mortality during the index hospitalization. Generalized linear modeling provided multivariate analysis, with entry of variables dependent on results of univariate analysis.

RESULTS

From January 2003 through September 2015, a total of 24,241 INFRA bypass, 8028 SUPRA bypass, 48,048 InfraPVI, 21,196 SupraPVI, and 3423 AMP patients met criteria for analysis, with a median follow-up of 18 (interquartile range, 8-33) months. Combining all procedures, overall mortality was lower among African Americans than among white Americans (12.4% vs 14.2%; P < .0001) but not death in the periprocedural period (1.1% vs 1.2%; P = .26). To account for differences in length of follow-up, Cox proportional hazards analysis confirmed that the African American race was independently associated with a significantly lower occurrence of overall mortality after INFRA bypass (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.70-0.88; P < .0009), InfraPVI (HR, 0.72; 95% CI, 0.67-0.78; P < .0001), and SupraPVI (HR, 0.77; 95% CI, 0.66-0.90; P = .0009) interventions but not after SUPRA bypass or AMP. Similarly, by Cox proportional hazards, Hispanic/Latino ethnicity was also independently associated with lower overall mortality after INFRA bypass (HR, 0.75; 95% CI, 0.62-0.91; P = .0030), InfraPVI (HR, 0.69; 95% CI, 0.62-0.78; P < .0001), and SupraPVI (HR, 0.68; 95% CI, 0.52-0.89; P = .0045) but not after SUPRA bypass or AMP.

CONCLUSIONS

Contrary to the published data for other forms of cardiovascular disease, African American patients as well as patients identified with Hispanic/Latino ethnicity with PAD included in the Society for Vascular Surgery Vascular Quality Initiative undergoing INFRA revascularization for lower extremity PAD experienced better overall survival compared with white Americans.

Ultralow Iodine Dose Transarterial Catheter-Directed CT Angiography for Fenestrated Endovascular Aortic Repair Planning

BACKGROUND

Preoperative planning for fenestrated endovascular aortic repair (fEVAR) requires high-quality cross-sectional imaging, most commonly computed tomography angiography (CTA). However, in the setting of chronic kidney disease (CKD), the iodine load delivered during conventional CTA is associated with risk for acute kidney injury (AKI). In this report, we describe the feasibility of using transarterial catheter directed CT angiography (tcd-CTA) with ultralow-dose iodine as an alternative for fEVAR planning in patients with stage 3-4 CKD to lower the risk of AKI.

METHODS

Preserum and postserum creatinine levels were retrospectively evaluated from 8 patients with stage 3-4 CKD who underwent tcd-CTA with 20 mL of Iohexol for fEVAR planning for the treatment of pararenal abdominal aortic aneurysms. The tcd-CTA images were evaluated by two vascular surgeons for adequacy for fEVAR planning and progression to fEVAR completion was recorded.

RESULTS

The mean serum creatinine before tcd-CTA was 2.1 ± .32 mg/dL, and the mean estimated glomerular filtration rate was 29.7 ± 6.31 mL/min/1.73 m(2). After tcd-CTA, the mean serum creatinine was 1.9 ± .25 mg/dL and the mean estimated glomerular filtration rate was 32.9 ± 5.12 mL/min/1.73 m(2). All 8 of the studies were determined to be adequate for fEVAR planning independently by two vascular surgeons. Six of the patients underwent successful fEVAR and 2 opted for watchful waiting.

CONCLUSIONS

tcd-CTA with ultralow-dose iodine is a feasible option for pre-fEVAR planning in patients with stage 3-4 CKD.

Non-invasive in vivo characterization of human carotid plaques with acoustic radiation force impulse ultrasound: comparison with histology after endarterectomy

Ischemic stroke from thromboembolic sources is linked to carotid artery atherosclerotic disease with a trend toward medical management in asymptomatic patients. Extent of disease is currently diagnosed by non-invasive imaging techniques that measure luminal stenosis, but it has been suggested that a better biomarker for determining risk of future thromboembolic events is plaque morphology and composition. Specifically, plaques that are composed of mechanically soft lipid/necrotic regions covered by thin fibrous caps are the most vulnerable to rupture. An ultrasound technique that non-invasively interrogates the mechanical properties of soft tissue, called acoustic radiation force impulse (ARFI) imaging, has been developed as a new modality for atherosclerotic plaque characterization using phantoms and atherosclerotic pigs, but the technique has yet to be validated in vivo in humans. In this preliminary study, in vivo ARFI imaging is presented in a case study format for four patients undergoing clinically indicated carotid endarterectomy and compared with histology. In two type Va plaques, characterized by lipid/necrotic cores covered by fibrous caps, mean ARFI displacements in focal regions were high relative to the surrounding plaque material, suggesting soft features were covered by stiffer layers within the plaques. In two type Vb plaques, characterized by heavy calcification, mean ARFI peak displacements were low relative to the surrounding plaque and arterial wall, suggesting stiff tissue. This pilot study illustrates the feasibility and challenges of transcutaneous ARFI for characterizing the material and structural composition of carotid atherosclerotic plaques via mechanical properties, in humans, in vivo.

"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.

Early protection and compression of residual limbs may improve and accelerate prosthetic fit: a preliminary study

BACKGROUND

The goal of rehabilitation following lower extremity amputation is to restore the highest level of independent function. As much as possible, this includes the functional use of a prosthetic device fitted to the residual limb. Early prosthetic fit depends, in turn, on rapid healing of the amputation site.

METHODS

We hypothesized that compliance with a novel custom-designed amputation protection and compression system (CAPCS) to the residual limb can accelerate and improve the likelihood of successful prosthesis use. We conducted a retrospective study of all patients who were offered CAPCS by certified prosthetists (Hanger Prosthetics and Orthotics, Bethesda, MD) during the period between April 2004 and November 2009. Variables included age, sex, indication for amputation, and compliance with CAPCS. Compliance was defined as consistent observed wearing of the CAPCS as directed. The primary end point was the fitting of a prosthetic device to the amputated limb, with time to prosthetic fit being the secondary outcome.

RESULTS

Out of 100 patients who were offered CAPCS (n = 100) during the study period, 76% were considered compliant (n = 76). Sixty five patients (65%) were ultimately fitted with prosthetic limbs. In multivariate analysis, we found that patients who had compliant use of CAPCS were significantly more likely to be successfully fit with prosthesis (72 vs. 42%, p = 0.005). At 100 days post amputation, the cumulative incidence of prosthesis fitting was significantly higher in CAPCS compliant patients (69.7 vs. 22.2%, p = 0.012).

CONCLUSIONS

Compliant use of a CAPCS following amputation is associated with earlier and more frequent use of a prosthetic. Based on this limited data set, a conclusion can be drawn that the potential exists to significantly improve functional outcomes after amputation, but well-designed prospective studies are needed to confirm this association.

Characterization of DISC formation and TNFR1 translocation to mitochondria in TNF-α-treated hepatocytes

Tumor necrosis factor receptor 1 (TNFR1) activation in hepatocytes can trigger apoptotic or inflammatory signaling. The factors that determine which signaling pathway dominates are not clear and are thought to relate to the efficiency of death-inducing signaling complex (DISC) formation. However, the steps involved in DISC formation in hepatocytes are poorly understood. In characterizing DISC formation within cultured hepatocytes, we demonstrated that TNF-α exposure leads to the rapid formation of a DISC involving TNF-α, the TNFR-associated death domain adaptor molecule (TRADD), the Fas-associated death domain adaptor molecule (FADD), caspase-8, TNFR-associated factor 2 (TRAF2), and receptor-interacting protein (RIP). The inclusion of the sensitizing agent actinomycin D both accelerated and amplified the appearance of the DISC. Notably, TNFR1 along with some DISC components also appeared within mitochondria within 30 minutes. Whereas TNFR1 consistently co-localized with the TRADD, FADD, the caspase-8, and TRAF2 in the cytosolic fraction, TNFR1 in the mitochondria was associated only with caspase-8 after TNF-α exposure. Similar observations were made in vivo using TNF-α with D-galactosamine. Actinomycin D alone also enhanced the appearance of DISC components in both cytosol and the mitochondria. Thus the DISC that includes TNFR1 forms in the cytosol of hepatocytes under both survival and pro-apoptotic conditions. The observations also suggest that TNF-α-mediated signaling includes the translocation of TNFR1 to mitochondria.

Nitrite-generated NO circumvents dysregulated arginine/NOS signaling to protect against intimal hyperplasia in Sprague-Dawley rats

Vascular disease, a significant cause of morbidity and mortality in the developed world, results from vascular injury. Following vascular injury, damaged or dysfunctional endothelial cells and activated SMCs engage in vasoproliferative remodeling and the formation of flow-limiting intimal hyperplasia (IH). We hypothesized that vascular injury results in decreased bioavailability of NO secondary to dysregulated arginine-dependent NO generation. Furthermore, we postulated that nitrite-dependent NO generation is augmented as an adaptive response to limit vascular injury/proliferation and can be harnessed for its protective effects. Here we report that sodium nitrite (intraperitoneal, inhaled, or oral) limited the development of IH in a rat model of vascular injury. Additionally, nitrite led to the generation of NO in vessels and SMCs, as well as limited SMC proliferation via p21Waf1/Cip1 signaling. These data demonstrate that IH is associated with increased arginase-1 levels, which leads to decreased NO production and bioavailability. Vascular injury also was associated with increased levels of xanthine oxidoreductase (XOR), a known nitrite reductase. Chronic inhibition of XOR and a diet deficient in nitrate/nitrite each exacerbated vascular injury. Moreover, established IH was reversed by dietary supplementation of nitrite. The vasoprotective effects of nitrite were counteracted by inhibition of XOR. These data illustrate the importance of nitrite-generated NO as an endogenous adaptive response and as a pathway that can be harnessed for therapeutic benefit.

Transient cortical blindness after thoracic endovascular aneurysm repair

We report a patient who presented with transient cortical blindness 12 hours after completion of a thoracic endovascular aneurysm repair. Computed tomography of the brain demonstrated no acute findings. The patient's symptoms resolved spontaneously after 72 hours. To our knowledge, this is the first report of transient cortical blindness after endovascular aortic aneurysm repair. This is an uncommon diagnosis that is important to recognize in a modern vascular surgery practice.

Systemic inflammation and remote organ injury following trauma require HMGB1

High-mobility group box 1 (HMGB1) is a 30-kDa DNA-binding protein that displays proinflammatory cytokine-like properties. HMGB1-dependent inflammatory processes have been demonstrated in models of sterile injury, including ischemia-reperfusion injury and hemorrhagic shock. Here, we tested the hypothesis that the systemic inflammatory response and associated remote organ injury that occur after peripheral tissue injury are highly dependent on HMGB1. Toll-like receptor 4 (TLR4) wild-type (WT) mice subjected to bilateral femur fracture after treatment with neutralizing antibodies to HMGB1 had lower serum IL-6 and IL-10 levels compared with mice treated with nonimmune control IgG. Similarly, compared with injured mice treated with control IgG, anti-HMGB1 antibody-treated mice had lower serum alanine aminotransferase levels and decreased hepatic and gut mucosal NF-κB DNA binding. TLR4 mutant (C3H/HeJ) mice subjected to bilateral femur fracture had less systemic inflammation and liver injury than WT controls. Residual trauma-induced systemic inflammation and hepatocellular injury were not ameliorated by treatment with a polyclonal anti-HMGB1 antibody, even though HMGB1 levels were transiently elevated just 1 h after injury in both WT and C3H/HeJ mice. Collectively, these data demonstrate a critical role for a TLR4-HMGB1 pathway in the initiation of systemic inflammation and end-organ injury following isolated peripheral tissue injury.

Increased interactive format for Morbidity & Mortality conference improves educational value and enhances confidence

OBJECTIVES

The Mortality and Morbidity (M&M) conference is a staple of surgical training programs. With reduced resident work hours, maximizing limited educational opportunities has become essential. We attempted to determine whether increasing the perceived educational value in M&M conference is associated with enhanced confidence levels in the future. We analyzed which features of M&M case reviews are associated with greater perceived educational value and enhanced confidence to deal with similar future clinical scenarios.

DESIGN

Educational process variables were prospectively collected for 47 consecutive cases reviewed over a 16-week period at a single institution's surgical M&M conference. General surgery residents completed self-reporting surveys rating the educational value of cases and impact on confidence in managing similar future clinical situations. Univariate regression analysis and multivariate regression analysis were calculated to study the relationship between various process variables and perceived educational and confidence values surveyed by residents.

SETTING

Tertiary academic medical center.

PARTICIPANTS

General surgery residents PGY1 to PGY5.

RESULTS

Increased perceived educational value was associated with increased confidence (p < 0.001). Perceived educational value was increased with more questioning of the audience, increasing explanations of cases, use of slides, increase in number of questions directed to attendings, use of radiologic images, the more junior the resident surveyed, and when teaching points were made specifically for the medical students in attendance. (p < 0.05) Level of confidence was increased with increased questioning to the audience, increased explanations, increased questioning of the attendings, and more junior the resident surveyed. Increased questioning of presenter did not increase perceived educational value or resident perceived confidence value.

CONCLUSIONS

These data demonstrate that audience interaction, not directed questioning of the presenter, may improve surgical resident perceived educational value and confidence in managing problems discussed at M&M. These data suggest that M&M moderators can play a central role in maximizing audience interaction and improve the educational value of this important conference.