Factors associated with successful median arcuate ligament release in an international, multi-institutional cohort.

OBJECTIVE: Prior research on median arcuate ligament syndrome has been limited to institutional case series, making the optimal approach to median arcuate ligament release (MALR) and resulting outcomes unclear. In the present study, we compared the outcomes of different approaches to MALR and determined the predictors of long-term treatment failure. METHODS: The Vascular Low Frequency Disease Consortium is an international, multi-institutional research consortium. Data on open, laparoscopic, and robotic MALR performed from 2000 to 2020 were gathered. The primary outcome was treatment failure, defined as no improvement in median arcuate ligament syndrome symptoms after MALR or symptom recurrence between MALR and the last clinical follow-up. RESULTS: For 516 patients treated at 24 institutions, open, laparoscopic, and robotic MALR had been performed in 227 (44.0%), 235 (45.5%), and 54 (10.5%) patients, respectively. Perioperative complications (ileus, cardiac, and wound complications; readmissions; unplanned procedures) occurred in 19.2% (open, 30.0%; laparoscopic, 8.9%; robotic, 18.5%; P < .001). The median follow-up was 1.59 years (interquartile range, 0.38-4.35 years). For the 488 patients with follow-up data available, 287 (58.8%) had had full relief, 119 (24.4%) had had partial relief, and 82 (16.8%) had derived no benefit from MALR. The 1- and 3-year freedom from treatment failure for the overall cohort was 63.8% (95% confidence interval [CI], 59.0%-68.3%) and 51.9% (95% CI, 46.1%-57.3%), respectively. The factors associated with an increased hazard of treatment failure on multivariable analysis included robotic MALR (hazard ratio [HR], 1.73; 95% CI, 1.16-2.59; P = .007), a history of gastroparesis (HR, 1.83; 95% CI, 1.09-3.09; P = .023), abdominal cancer (HR, 10.3; 95% CI, 3.06-34.6; P < .001), dysphagia and/or odynophagia (HR, 2.44; 95% CI, 1.27-4.69; P = .008), no relief from a celiac plexus block (HR, 2.18; 95% CI, 1.00-4.72; P = .049), and an increasing number of preoperative pain locations (HR, 1.12 per location; 95% CI, 1.00-1.25; P = .042). The factors associated with a lower hazard included increasing age (HR, 0.99 per increasing year; 95% CI, 0.98-1.0; P = .012) and an increasing number of preoperative diagnostic gastrointestinal studies (HR, 0.84 per study; 95% CI, 0.74-0.96; P = .012) Open and laparoscopic MALR resulted in similar long-term freedom from treatment failure. No radiographic parameters were associated with differences in treatment failure. CONCLUSIONS: No difference was found in long-term failure after open vs laparoscopic MALR; however, open release was associated with higher perioperative morbidity. These results support the use of a preoperative celiac plexus block to aid in patient selection. Operative candidates for MALR should be counseled regarding the factors associated with treatment failure and the relatively high overall rate of treatment failure.

Variability in Antithrombotic Therapy after Infrainguinal Lower Extremity Bypass.

BACKGROUND: Antiplatelet monotherapy is recommended after infrainguinal lower extremity bypass (LEB). However, there is a paucity of high-quality data to guide therapy, and antiplatelet therapy is often prescribed in combination with anticoagulation. We therefore aimed to assess the variability in the use of antithrombotic therapy after infrainguinal LEB. METHODS: The Vascular Quality Initiative dataset (2015-2021) was retrospectively reviewed to determine discharge patterns of antithrombotic therapy for all patients undergoing infrainguinal LEB. Monotherapy on discharge was defined as either single antiplatelet therapy (SAPT) or single anticoagulant (SAC). Combination therapy was dual antiplatelet therapy (DAPT), anticoagulant + antiplatelet (ACAP), or triple therapy. Hierarchical multivariable logistic regression with random effects for physician and center was used to identify predictors of combination therapy. Median odds ratios (MOR) were derived to quantify degree of variability in antithrombotic therapy. RESULTS: There were 29,507 patients undergoing infrainguinal LEB (monotherapy = 10,634 vs. combination therapy = 18,873). SAPT (90.6%) was the most common form of monotherapy, while DAPT (57.7%) and ACAP (34.6%) were the most common combination therapies. Patients undergoing LEB to popliteal targets were more likely to be prescribed monotherapy (SAC or SAPT) than to infra-popliteal targets (60.6% vs. 56.6%, P < 0.001). Combination therapy (DAPT, ACAP, or triple therapy) was more often used in patients with tibial or plantar arteries as the bypass target. Patients undergoing bypass using autogenous vein were more likely to receive monotherapy compared with those receiving other conduits (64.8% vs. 52.9%, P < 0.001), while patients with prosthetic grafts were more likely to receive combination therapy (37.9% vs. 28.2%, P < 0.001). There were no significant differences in postoperative bleeding (P = 0.491) or 30-day mortality (P = 0.302) between the two groups. Prior peripheral vascular interventions (PVI) (odds ratio [OR]: 1.89, 95% confidence interval [CI]: 1.79-1.99), concomitant PVI (OR: 1.83, 95% CI: 1.66-2.02), prosthetic graft use (OR: 1.74, 95% CI: 1.64-1.85), prior percutaneous coronary intervention (OR: 1.53, 95% CI: 1.43-1.65), plantar distal target (OR: 1.46, 95% CI: 1.29-1.65), alternative conduits (OR: 1.39, 95% CI: 1.25-1.53), and tibial distal targets (OR: 1.36, 95% CI: 1.28-1.44) were independent predictors of combination therapy in a multivariable regression model. Upon adjusting for patient-level factors, there was significant physician-level (MOR: 1.65, 95% CI 1.61-1.67) and center-level (MOR: 1.64, 95% CI 1.57-1.69) variability in the selection of antithrombotic therapy. CONCLUSIONS: Significant physician- and center-level variability in the use of antithrombotic regimens after infrainguinal bypass reflects the paucity of available evidence to guide therapy. Pragmatic trials are needed to assess antithrombotic strategies and guide recommendations aimed at optimizing cardiovascular and graft-specific outcomes after LEB.

Utility of Hook Sign in the Diagnosis of Median Arcuate Ligament Syndrome.

BACKGROUND: Median arcuate ligament syndrome (MALS) is a clinical syndrome caused by compression of the celiac artery by the median arcuate ligament that often manifests with nonspecific abdominal pain. Identification of this syndrome is often dependent on imaging of compression and upward bending of the celiac artery by lateral computed tomography angiography, the so-called "hook sign." The purpose of this study was to assess the relationship of radiologic characteristics of the celiac artery to clinically relevant MALS. METHODS: An institutional review board-approved retrospective chart review from 2,000 to 2,021 of 293 patients at a tertiary academic center diagnosed with celiac artery compression (CAC) was performed. Patient demographics and symptoms of 69 patients who were diagnosed with symptomatic MALS were compared to 224 patients without MALS (but with CAC) per electronic medical record review. Computed tomography angiography images were reviewed and the fold angle (FA) was measured. The presence of a hook sign (defined as a visual FA < 135°), as well as stenosis (defined as >50% of luminal narrowing on imaging) were recorded. Wilcoxon rank-sum test and Chi-squared test were used for comparative analysis. Logistic model was run to relate the presence of MALS with comorbidities and radiographic findings. RESULTS: Imaging was available in 59 patients (25 males, 34 females) and 157 patients (60 males, 97 females) with and without MALS, respectively. Patients with MALS were more likely to have a more severe FA (120.7 ± 33.6 vs. 134.8 ± 27.9, P = 0.002). Males with MALS were also more likely to have a more severe FA compared with males without MALS (111.1 ± 33.7 vs. 130.4 ± 30.4, P = 0.015). In patients with body mass index (BMI) >25, MALS patients also had narrower FA compared with patients without MALS (112.6 ± 30.5 vs. 131.7 ± 30.3, P = 0.001). The FA was negatively correlated with BMI in patients with CAC. The hook sign and stenosis were associated with diagnosis of MALS (59.3% vs. 28.7%, P < 0.001, and 75.7% vs. 45.2%, P < 0.001, respectively). In logistic regression, pain, stenosis, and a narrow FA were statistically significant predictors of the presence of MALS. CONCLUSIONS: The upward deflection of the celiac artery in patients with MALS is more severe compared with patients without MALS. Consistent with prior literature, this bending of the celiac artery is negatively correlated with BMI in patients with and without MALS. When demographic variables and comorbidities are considered, a narrow FA is a statistically significant predictor of MALS. Regardless of MALS diagnosis, a hook sign was associated with narrower FA. While demographics and imaging findings may inform MALS diagnosis, clinicians should not rely on a visual assessment of a hook sign but should quantitatively measure the anatomic bending angle of the celiac artery to assist with the diagnosis and understand the outcomes.

Frailty and outcomes following revascularization of lower-extremity peripheral artery disease: Insights from the Vascular Quality Initiative (VQI).

BACKGROUND: Multiple frailty screening tools are implemented; however, it is unclear whether they perform in a comparable way for both frailty detection and prediction of perioperative outcomes in patients undergoing lower-extremity revascularization. METHODS: Patients undergoing lower-extremity revascularization were identified from the Vascular Quality Initiative (VQI) national database. Two cohorts were established based on the revascularization type (percutaneous vascular interventions (PVI) or lower-extremity bypass). Frailty was assessed by the 5-item modified frailty index (mFI-5) and the VQI-derived risk analysis index (RAI). RESULTS: Out of 134,081 patients undergoing PVI, frailty was identified in 67% by mFI-5 and 28% by RAI. Similarly, out of 41,316 patients in the bypass cohort, frailty was identified in 69% by mFI-5 and 16% by RAI. There was little agreement between the two frailty tools for both vascular cohorts (PVI: kappa: 0.17; bypass: kappa: 0.13). In an adjusted analysis, frailty as assessed by mFI-5 and RAI was associated with higher odds of mortality in both cohorts (p < 0.001). A significant association between frailty and unplanned amputations was only noted in the bypass cohort when RAI was applied (OR: 1.50, p < 0.01). The addition of frailty to traditional PAD risk factors marginally improved model performance to predict mortality and unplanned major amputations. CONCLUSION: There was significant variation in frailty detection by mFI-5 and RAI. Although frailty was associated with mortality, the predictive value of these tools in predicting outcomes in PAD was limited. Future research should focus on designing new frailty screening tools specific to the PAD population.

A Pilot Study of a Standardized Smoking Cessation Intervention for Patients with Vascular Disease.

BACKGROUND: The goal of this study is to evaluate the efficacy of a smoking cessation intervention performed by a vascular surgery provider compared with current smoking cessation practices. METHODS: Patients with peripheral arterial and aneurysmal disease who presented to the vascular surgery service at a tertiary care center over a 9-month period were randomized to either control or intervention group. Both control and intervention groups received 2 weeks of free nicotine patches and referral to an outpatient smoking-cessation program. The intervention group additionally received a brief presentation by a vascular surgeon regarding the benefits of smoking cessation, with a focus on vascular complications. At enrollment and at follow-up, patients underwent carbon monoxide breath testing and completed a survey. The primary outcome was smoking cessation or reduction among control and intervention groups in patients who underwent medical management, endovascular procedures, or open surgical procedures. Fisher's exact test was used to assess the primary outcome among groups. RESULTS: Fifty-nine patients were enrolled in the trial initially, but 55 had 1-month follow-up (control n = 28, intervention n = 27) and 52 had long-term follow-up (control n = 28, intervention n = 24). By long-term follow-up, 40 patients (77%) had reduced smoking by at least 50% and 16 patients (31%) had quit completely. At long-term follow-up, 88% of patients in the intervention group and 68% of patients in the control group reduced smoking (P = 0.1). CONCLUSIONS: A large proportion of vascular patients who received 2 weeks of nicotine replacement with or without the addition of brief smoking cessation counseling delivered by a vascular surgery provider were able to reduce smoking and maintain reduction after 6 months. Delivery of a brief standardized smoking cessation counseling session by a vascular surgery provider is safe and feasible. Additional randomized controlled trials with large enrollment periods and long follow-up are needed to determine the efficacy of this intervention in comparison to standard care.

Higher Inpatient Mortality for Women after Intervention for Lifestyle Limiting Claudication.

BACKGROUND: Sex-related differences in outcomes have been identified in patients with peripheral artery disease (PAD). We hypothesized that women with PAD would have equivalent inpatient mortality with men after vascular intervention. METHODS: Patients with a primary diagnosis of critical limb ischemia (CLI) or lifestyle-limiting claudication (LLC) receiving endovascular (EV) or open surgical repair from 2003-2012 were identified from the Nationwide Inpatient Sample. Demographics, comorbidities, and inpatient mortality were analyzed by chi-squared tests of independence and independent-samples t-tests. Logistic regression analysis was performed to identify predictors of inpatient mortality. SPSS 24 software was used with P < 0.05 considered statistically significant. RESULTS: We identified 139,435 (59,432 women and 80,003 men) individuals meeting the aforementioned criteria. Women were older than men (71.5 years vs. 68.2, P < 0.001). There were no differences in racial distribution but women had lower rates of diabetes (38.6% vs. 39.7%, P < 0.001), chronic obstructive pulmonary disease (17.9% vs. 19.5%, P < 0.001), and coronary artery disease (38.6% vs. 47.4%, P < 0.001), while having a higher rate of hypertension (60.0% vs. 56.1%, P < 0.001). There was no sex-related difference in the rate of chronic renal failure. Women had higher inpatient mortality than men after vascular intervention (1.3% vs. 1.1%, P < 0.001). When stratified by surgical technique, women also had higher inpatient mortality after EV repair (1.0% vs. 0.8%, P < 0.05) and open repair (1.9% vs 1.3%, P < 0.001). When separated by admitting diagnosis, women with CLI had higher inpatient mortality than men after open surgery (2.3% vs. 1.9%, P < 0.05) but not after EV intervention. Women with LLC had higher inpatient mortality after both open (0.6% vs. 0.3%, P < 0.05) and EV surgery (0.3% vs. 0.1%, P < 0.05). Regression analysis revealed female sex as an independent predictor of inpatient mortality in patients with LLC (OR, 1.74; 95% CI 1.30-2.32, P < 0.001) but not CLI. CONCLUSIONS: Women had higher inpatient mortality than men after vascular intervention for PAD. Women were also older and more likely to have EV intervention than men. Subgroup analysis suggests that these sex-related differences in inpatient mortality are more pronounced in patients with LLC than with CLI. Furthermore, regression analysis shows that sex is a significant predictor for patients diagnosed with LLC but not with CLI. Treatment guidelines should include consideration of sex in their indications for revascularization, particularly for patients diagnosed with LLC.

A survey of vascular specialists' practice patterns of inferior vena cava filter placement and retrieval.

OBJECTIVES: The placement of inferior vena cava filters (IVCF) continues to rise. Vascular specialists adopt different practices based on local expertise. This study was performed to assess the attitudes of vascular specialists towards the placement and retrieval of IVCF. METHODS: An online survey of 28 questions related to practice patterns regarding IVCF was administered to 1429 vascular specialists. Vascular specialists were categorized as low volume if they place less than three IVCF per month and high volume if they place at least three IVCF per month. The responses of high volume and low volume were compared using two-sample t-tests and Chi-square tests. RESULTS: A total of 259 vascular specialists completed the survey (18% response rate). There were 191 vascular surgeons (74%) and 68 interventional radiologists (26%). The majority of responders were in academic practice (67%) and worked in tertiary care centers (73%). The retrievable IVCF of choice was Celect (27%) followed by Denali (20%). Forty-two percent used a temporary IVCF and left it in situ instead of using a permanent IVCF. Eighty-two percent preferred placing the tip of the IVCF at or just below the lowest renal vein. Thirty-one percent obtained a venous duplex of the lower extremities prior to retrieval while 24% did not do any imaging. There were 132 (51%) low volume vascular specialists and 127 (49%) high volume vascular specialists. Compared to low volume vascular specialists, significantly more high volume vascular specialists reported procedural times of less than 30 min for IVCF retrieval (57% vs. 42%, P = 0.026). There was a trend for high volume to have fewer unsuccessful attempts at IVCF retrieval but that did not reach statistical significance ( P = .061). High volume were more likely to have attempted multiple times to retrieve an IVCF (66% vs. 33%, P < .001), and to have used bronchoscopy forceps (32% vs. 14%, P = .001) or a laser sheath (14% vs. 2%, P < .001) for IVCF retrieval. In general, vascular specialists were not comfortable using bronchoscopy forceps (65%) or a laser sheath (82%) for IVCF retrieval. CONCLUSIONS: This study underscores significant variability in vascular specialists practice patterns regarding IVCF. More studies and societal guidelines are needed to define best practices.

Endovascular interventions decrease length of hospitalization and are cost-effective in acute mesenteric ischemia.

OBJECTIVE: Acute mesenteric ischemia (AMI) continues to be one of the most devastating diagnoses requiring emergent vascular intervention. There is a national trend toward increased use of endovascular procedures, with improved survival for the treatment of these patients. Our aim was to evaluate whether this trend has changed the treatment of AMI and the subsequent impact on length of hospitalization and hospitalization costs. METHODS: We identified all patients admitted for AMI from the National Inpatient Sample from 2004 to 2014 who received open surgical revascularization (OPEN) or an endovascular intervention (ENDO). Primary end points included length of hospital stay and cost of hospitalization. Our secondary end points included acute kidney injury (AKI), in-hospital mortality, and routine discharge. RESULTS: Among 10,381 discharges identified in the data set, 3833 (37%; 97.5% confidence interval [CI], 35%-39%) were male patients with a mean age of 69 years (range, 18-98 years); 4543 (44%; 97.5% CI, 41%-47%) patients were treated ENDO, and 5839 (56%; 97.5% CI, 53%-59%) patients were treated OPEN. Although a higher proportion of patients in the ENDO group (28%; 97.5% CI, 24%-31%) vs the OPEN group (14%; 97.5% CI, 11%-16%) had a moderate to severe Charlson Comorbidity Index (P < .0001), ENDO was associated with a lower mortality rate (12.3% [97.5% CI, 9.8%-14.8%] vs 33.1% [97.5% CI, 29.9%-36.2%]; P < .0001) and a lower mean hospitalization cost ($41,615 [97.5% CI, $38,663-$44,567] vs $60,286 [97.5% CI, $56,736-$63,836]; P < .0001). After propensity-adjusted logistic regression analysis, OPEN retained a significant association with higher mortality than ENDO (odds ratio, 3.0; 97.5% CI, 2.2-4.1) and with higher costs (mean, $9196; 97.5% CI, $3797-$14,595). Patients in the OPEN group had higher risk for AKI (P < .0001) and discharge to a skilled nursing facility (P < .0001) rather than home. CONCLUSIONS: Although the rate of ENDO continues to rise nationally, it still has not surpassed OPEN revascularization in the face of AMI. Patients treated endovascularly demonstrated one-third the rate of in-hospital mortality (odds ratio, 3.0; 97.5% CI, 2.2-4.1), an increased hazard ratio for discharge alive (hazard ratio, 2.27; 97.5% CI, 2.00-2.58), and a cost saving of $9196 (97.5% CI, $3797-$14,595) per hospitalization. Furthermore, they were less likely to develop AKI and to be discharged home after hospitalization.

Improved mortality in treatment of patients with endovascular interventions for chronic mesenteric ischemia.

OBJECTIVE: Chronic mesenteric ischemia (CMI) continues to be a devastating diagnosis. There is a national trend toward increased use of endovascular procedures with improved survival for the treatment of these patients. Our aim was to evaluate whether this trend has changed CMI patients' length of hospitalization and health care cost. METHODS: We identified all patients admitted for CMI from the National Inpatient Sample (NIS) from 2000 to 2014. Our primary end points included length of hospital stay (LOS) and cost of hospitalization (COH). Our secondary end points included mortality assessment of the CMI hospitalization. RESULTS: There were 15,475 patients admitted for CMI. The mean age of patients was 71 years, and 4022 (26.0%) were male. There were 10,920 (70.6%) patients treated endovascularly (ENDO) and 4555 (29.4%) patients treated in an open fashion (OPEN). Although a higher proportion of patients in the ENDO (43.3%) group vs OPEN (33.1%) had a Charlson Comorbidity Index score of ≥2 (P < .0001), they had a lower mortality rate (2.4% vs 8.7%; P < .0001), lower mean LOS (6.3 vs 14.0 days; P < .0001), and lower COH ($21,686 vs $42,974; P < .0001). After adjusting for clinical and hospital factors, OPEN continued to demonstrate higher mortality than ENDO (odds ratio, 7.2; 95% confidence interval, 4.9-10.6; P < .0001), longer LOS (mean, +9.7 days; P < .0001), and higher COH (mean, +$25,834; P < .0001). CONCLUSIONS: The rate of ENDO continues to rise nationally in the treatment of CMI patients. After adjusting for clinical and hospital factors, patients in the ENDO group tend to have lower in-hospital mortality of 2.4% and lower LOS by 10 days, and they incur a cost saving of >$25,000 compared with patients in the OPEN group. ENDO should be considered first line of therapy for patients with CMI.

Increased mortality in octogenarians treated for lifestyle limiting claudication.

OBJECTIVE: Treatment for lifestyle limiting claudication (LLC) that is due to infra-inguinal peripheral artery disease relies on either bypass, angioplasty, and/or stenting. Given the enthusiasm and shift toward more endovascular therapy for treatment of LLC, we sought to analyze whether octogenarians benefit from infra-inguinal interventions in the same manner as their younger counterparts. METHODS: We identified all patients admitted for elective treatment of LLC from the Nationwide Inpatient Sample from 2003 to 2012, who received open surgical or endovascular intervention for infra-inguinal peripheral arterial disease. These patients were divided into two groups including those between the ages 60-80 years (younger cohort) and those older than 80 years (octogenarians). Primary end-points included morbidity and mortality and the secondary end-points were length of hospital stay (LOS) and disposition after dismissal. RESULTS: Among 59,323 discharges identified in the dataset, 34,658 (58%) were males. There were 50,323 (85%) patients in the younger cohort and 9,000 (15%) octogenarians. The mean age was 69.9 ± 5.7 years and 84.2 ± 3.0 years for the younger cohort and octogenarians, respectively. The mean Charlson comorbidity index (CCI) was higher in our younger cohort (2.1 ± 1.1, P < 0.001). Octogenarians mainly treated with open surgery prior to 2004 are now treated endovascularly and this trend has remained stable. The younger cohort's treatment modality has fluctuated through the study period and most recently is treated mainly with open surgery. The rate of acute kidney injury, exacerbation of congestive heart failure and mortality was higher in octogenarians (P < 0.001). The rate of infectious wound complications was higher in the younger cohort (P < 0.05). Octogenarians have longer LOS and are dismissed in higher percentage to a skilled nursing facility (P < 0.001). On binary logistic regression analysis, age over 80 years, female sex, higher CCI and having an open as opposed to an endovascular procedure are independent predictors of in-hospital mortality. CONCLUSIONS: Although endovascular techniques seem to dominate the care for octogenarians with LLC, the overall morbidity and mortality rates are significantly higher in this patient population. Other options such as medical management and/or supervised exercise therapy should be explored in this patient group.

Regulation of Yes-Associated Protein by Laminar Flow.

BACKGROUND: The cells lining the endothelium of blood vessels are recognized as playing critical roles in vascular health and disease. The mechanisms that regulate endothelial cells (ECs) proliferation and release of mediators remain poorly understood but represent a potential source of disease modulation. Actin-cytoskeleton remodeling and cell shape have been suggested as key regulators of phosphorylation of yes-associated protein (YAP) which controls cellular growth and proliferation. Because different types of flow have been shown to affect cell shape and cytoskeleton differently, we hypothesized that the level of phosphorylated yes-associated protein (pYAP; serine 127) decreases in EC exposed to pulsatile uniform flow or steady laminar flow, whereas exposure to pulsatile disturbed flow causes an increase or no change. METHODS: Human umbilical vein endothelial cells (HUVECs) were exposed to pulsatile uniform flow, pulsatile disturbed flow, or steady laminar flow and analyzed by immunoblotting. RESULTS: Exposure of HUVECs to steady laminar flow caused a significant decrease in the levels of pYAP (69.7 + 2.6%, P < 0.05), whereas total YAP levels remained nearly unchanged. Conversely, exposure to either pulsatile uniform or disturbed flow caused a significant decrease in the levels of both pYAP (63.2 + 10.9% and 69.8 + 11.9%, respectively; P < 0.05) and total YAP (57.1 + 17.8% and 58.4 + 16.3%, respectively; P < 0.05). Addition of MG132, a ubiquitin-proteasome system inhibitor, failed to significantly inhibit the decrease in the levels of total YAP in HUVECs exposed to either pulsatile uniform or disturbed flow. CONCLUSIONS: Flow causes a decrease in pYAP. The observed decrease in total YAP levels with pulsatile flow is due to degradation via a proteasome-independent mechanism. This may be a potential target for intervention for disease states such as atherosclerosis and intimal hyperplasia.

Acute Limb Ischemia in an 8-Year-Old Patient: A Case Report.

We report the case of an 8-year-old patient with a history of nephrotic syndrome, who presented to the emergency department with right foot pain. The patient's mother described intermittent pain that woke her son from sleep and was accompanied by the foot turning purple and becoming cold to touch. Physical examination revealed capillary refill of over 10 seconds in the right and less than 2 seconds in the left foot. Ankle-brachial indices (ABIs) were 0.0 on the right and 0.96 on the left. The patient was admitted and started on therapeutic intravenous heparin. After consultation with his parents, right lower extremity angiography and thrombolysis was performed over 2 days. He subsequently underwent fasciotomy and amputation of the tip of all 5 toes. Eighteen months later, there is no leg length discrepancy, he is walking with foot inserts and has normal ABIs bilaterally.

Systemic and cell-specific mechanisms of vasculopathy induced by human immunodeficiency virus and highly active antiretroviral therapy.

OBJECTIVE: Patients infected with human immunodeficiency virus (HIV) have higher rates of dyslipidemia, atherosclerosis, and chronic inflammation that can damage the vascular system compared with the general population. This can be attributed both to HIV itself and to highly active antiretroviral therapy (HAART) they receive. This review outlines the mechanisms by which HIV and HIV medications can cause vascular complications and identifies strategic areas of research to treat these dysfunctions. REVIEW: HIV and HAART affect the vascular system through several mechanisms that target systemic or metabolic systems and specific cells. HIV causes dyslipidemia and chronic immune activation, which can contribute to atherosclerosis. In addition, HIV damages macrophages, endothelial cells, smooth muscle cells, and platelets, and this damage also plays a role in the development of atherosclerosis. HAART, particularly protease inhibitors, interferes with cholesterol metabolism and can affect macrophages, endothelial cells, and smooth muscle cells. The metabolic changes and cell damage induced by HIV and HAART put HIV patients at increased risk for atherosclerosis, dyslipidemia, and serious cardiovascular events such as myocardial infarction and stroke. CONCLUSIONS: HIV patients have increased risk of developing potentially life-threatening cardiovascular pathology, which cannot be explained by traditional cardiovascular risk factors alone. More research is needed into therapies to target this HIV-specific vasculopathy.

Distal embolization during lower extremity endovascular interventions.

OBJECTIVE: Distal embolization (DE) during peripheral arterial endovascular interventions is a well-known complication that is poorly studied. The goal of this study was to determine the incidence, risk factors, and effect of DE on the outcomes of lower extremity endovascular interventions (LEIs). METHODS: All LEIs between 2010 and 2014 in the Vascular Study Group of New England (VSGNE) database were reviewed. Patient characteristics were analyzed to determine predictors of DE. LEIs involving the superficial femoral artery (SFA) were reviewed to assess the effect of type of treatment on DE. The outcomes examined were loss of patency, limb loss, and mortality after LEI involving the SFA. A multivariable regression was used to determine predictors of DE. RESULTS: There were 10,875 procedures. The incidence of DE was 17.3 per 1000 procedures, and 68% required treatment (57% endovascular, 11% open surgery). DE was more common in patients treated for critical limb ischemia compared with claudication (relative risk [RR], 2.06; 95% confidence interval [CI], 1.24-3.45; P = .006) and for emergency interventions compared with elective (RR, 2.98; 95% CI, 1.22-7.30; P = .017). DE increased with the number of arteries treated (P < .0001) and with the length of occlusion (P < .0001). The SFA was the most commonly treated artery (4751 [43.7%]). In comparison with atherectomy and balloon angioplasty, stenting alone (RR, 0.36; 95% CI, 0.17-0.73; P = .005), balloon angioplasty alone (RR, 0.23; 95% CI, 0.13-0.41; P < .0001), and combined stenting and balloon angioplasty (RR, 0.29; 95% CI, 0.17-0.49; P < .0001) were associated with a significantly lower risk of DE. DE was not significantly associated with loss of patency, major amputation, or mortality. CONCLUSIONS: The incidence of DE during LEIs is 1% to 2% in the VSGNE database, and most patients are treated with additional endovascular interventions. The incidence increases in patients with critical limb ischemia and with the use of atherectomy.

Explantation of infected aortic aneurysm and endograft with ascending aorta to mesenteric bypass for mesenteric ischemia.

A 65-year-old man presented with an infected perivisceral aortic aneurysm after previous treatment of an abdominal aortic aneurysm with an endograft. On presentation, he was septic and had occlusion of the celiac, superior mesenteric, inferior mesenteric, and bilateral renal arteries. He underwent a three-stage procedure: first, axillobifemoral bypass; then resection of the thoracoabdominal aorta; and finally bypass from the ascending aorta to the celiac and superior mesenteric arteries with a rifampin-soaked Gelsoft graft (Vascutek, Renfrewshire, Scotland). The abdominal pain resolved, and the patient remains symptom free 10 months postoperatively. This rare surgical revascularization technique offered a nontraditional solution to a difficult surgical issue.

Percutaneous endovascular aneurysm repair in morbidly obese patients.

OBJECTIVE: Endovascular aneurysm repair (EVAR) with percutaneous femoral access (PEVAR) has several potential advantages. Morbidly obese (MO) patients present unique anatomical challenges and have not been specifically studied. This study examines the trends in the use of PEVAR and its surgical outcomes compared with open femoral cutdown (CEVAR) in MO patients. METHODS: The American College of Surgeons National Surgical Quality Improvement Program files for the years 2005 to 2013 were reviewed. The study included all MO patients (body mass index [BMI] ≥40 kg/m2) undergoing EVAR. Patients were categorized as having CEVAR if they had any one of 11 selected Current Procedural Terminology (American Medical Association, Chicago, Ill) codes describing an open femoral procedure. The PEVAR group included any remaining patients who had only codes for EVAR and endovascular procedures. Linear correlation was used to evaluate temporal trends in the use of PEVAR among MO patients. Baseline comorbidities and surgical outcomes were compared between the PEVAR and CEVAR groups using χ2 tests or t-tests. RESULTS: There were 833 MO patients (470 CEVAR and 363 PEVAR) constituting 3.0% of all patients undergoing EVAR. The use of PEVAR in MO patients significantly increased from 27.3% of total EVARs in the years 2005 to 2006 to 48.6% in 2013 (P = .039). The two groups had similar baseline characteristics, including age, BMI, comorbidities, and emergency procedures, except for history of severe chronic obstructive pulmonary disease (29.6% CEVAR vs 22.6% PEVAR; P = .024). PEVAR patients had shorter duration of anesthesia (244 vs 260 minutes; P = .048) and shorter total operation time (158 vs 174 minutes; P = .002). PEVAR patients had significantly decreased wound complications (5.5% vs 9.4%; P = .039). There was a trend towards PEVAR patients being more likely to be discharged home than to a facility (93.6% vs 87.8%; P = .060). There was no difference in any other complication or mortality. A subgroup analysis of 109 superobese patients with BMI ≥50 kg/mg2 (59 CEVAR and 50 PEVAR) demonstrated no significant differences in outcomes between groups. CONCLUSIONS: PEVAR is increasingly used in MO patients and decreases operating time and rates of wound infection compared with CEVAR. The advantages of PEVAR seem to be lost in the superobese patients.

Clinical Decision Analysis and Markov Modeling for Surgeons: An Introductory Overview.

This study addresses the use of decision analysis and Markov models to make contemplated decisions for surgical problems. Decision analysis and decision modeling in surgical research are increasing, but many surgeons are unfamiliar with the techniques and are skeptical of the results. The goal of this review is to familiarize surgeons with techniques and terminology used in decision analytic papers, to provide the reader a practical guide to read these papers, and to ensure that surgeons can critically appraise the quality of published clinical decision models and draw well founded conclusions from such reports.First, a brief explanation of decision analysis and Markov models is presented in simple steps, followed by an overview of the components of a decision and Markov model. Subsequently, commonly used terms and definitions are described and explained, including quality-adjusted life-years, disability-adjusted life-years, discounting, half-cycle correction, cycle length, probabilistic sensitivity analysis, incremental cost-effectiveness ratio, and the willingness-to-pay threshold.Finally, the advantages and limitations of research with Markov models are described, and new modeling techniques and future perspectives are discussed. It is important that surgeons are able to understand conclusions from decision analytic studies and are familiar with the specific definitions of the terminology used in the field to keep up with surgical research. Decision analysis can guide treatment strategies when complex clinical questions need to be answered and is a necessary and useful addition to the surgical research armamentarium.

Use of hyperspectral imaging to assess endothelial dysfunction in peripheral arterial disease.

BACKGROUND: Hyperspectral imaging (HSI) is a technology that with limited training can noninvasively measure oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin concentrations in the skin to create an oxygenation map. This pilot study determined whether HSI could be used to demonstrate vascular dysfunction in the upper extremity of patients with peripheral artery disease (PAD) and coronary artery disease (CAD). METHODS: This prospective study included 93 consecutive, consented patients presenting to the vascular clinic, with and without diagnosed arterial disease, and healthy volunteers. Patients underwent HSI at the upper arm, forearm, and palm before and after cuff occlusion (50 mm Hg above systolic) for 5 minutes. Medical records of enrolled patients were reviewed for demographic data, medications, surgical history, and other pertinent information. RESULTS: Significant changes occurred with oxyHb, with minimal to no effects on deoxygenated hemoglobin. The highest values of oxyHb were detected in the upper arm, followed by the forearm and hand. The absolute and percentage change in oxyHb measured in the upper arm and forearm was significantly reduced in controls aged >40 years compared with controls aged <40 years. Significant differences were noted in the upper arm oxyHb absolute change in response to cuff occlusion comparing PAD or CAD (n = 47) vs the older control cohort (P = .028). When the 23 patients with PAD only were separated out, the upper arm oxyHb response to cuff occlusion is even more significantly impaired (P < .01) compared with controls. CONCLUSIONS: Our study suggests the ability of HSI to assess the presence of PAD or CAD based on systemic vascular dysfunction at sites remote from the clinically diseased vascular bed. This could enable early screening and tracking of arterial disease patients before the development of clinically advanced disease.

PECAM-1 phosphorylation and tissue factor expression in HUVECs exposed to uniform and disturbed pulsatile flow and chemical stimuli.

INTRODUCTION: We analyzed the relationship between platelet endothelial cell adhesion molecule-1 (PECAM-1) activation and tissue factor (TF) RNA expression in human umbilical vein endothelial cells (HUVECs) exposed to mechanical and chemical stimulation. METHODS: Fifty percent confluent and 100% confluent HUVEC cultures were exposed to pulsatile forward flow, as a model for uniform flow, or pulsatile to-and-fro flow, as a model for disturbed flow, using a parallel-plate flow chamber system for up to 4 hours in the presence or absence of 4 U/mL thrombin. Protein lysates were immunoprecipitated for PECAM-1 and then immunoblotted with anti-phospho-tyrosine antibody. TF RNA expression was determined using quantitative reverse transcription polymerase chain reaction. RESULTS: HUVECs exposed to disturbed flow induced higher TF expression at 4 hours than HUVECs exposed to uniform flow in sparse cultures (16.8 ± 5.8 vs 5.1 ± 1.2; P < .05). HUVECs exposed to disturbed flow and thrombin induced higher TF RNA expression at 4 hours than cultures exposed to uniform flow and thrombin in both confluent (47.0 ± 6.0 vs 30.2 ± 4.9; P < .05) and sparse (72.3 ± 10.7 vs 49.8 ± 4.7; P < .05) cultures. In confluent HUVEC cultures, PECAM-1 is minimally phosphorylated by disturbed and uniform flow, while in sparse HUVEC cultures, PECAM-1 phosphorylation at 15 minutes is greater in both disturbed and uniform flow (2.0 ± 0.2 and 2.1 ± 0.4 respectively; P < .05). Thrombin treatment of static HUVECs exhibited greater PECAM-1 phosphorylation at 15 minutes in confluent compared with sparse cultures (3.0 ± 0.5 vs 2.3 ± 0.1; P < .05). PECAM-1 phosphorylation of HUVECs exposed to both flow and thrombin is significantly higher in sparse cultures compared with either flow or thrombin stimulation alone but was suppressed in confluent cultures. CONCLUSIONS: The significantly higher TF RNA expression induced by disturbed flow and cell confluence indicates that suppression of PECAM-1 phosphorylation may be an important contributory mechanical signal pathway that promotes TF expression when HUVECs are exposed to disturbed flow.

Consequences of hypogastric artery ligation, embolization, or coverage.

OBJECTIVE: Interruption of the hypogastric artery by ligation, embolization, or coverage frequently results in ischemic complications. The aim of this study was to compare the rate and risk factors for the development of ischemic complications after interruption of the hypogastric artery in obstetrics and gynecology (OBG), vascular surgery, oncology, and trauma patients. METHODS: MEDLINE, Ovid, and Scopus were searched for articles containing data of patients who underwent interruption of the hypogastric artery. Based on the indication, details of the procedure, and complications developed, data were categorized and a systematic review was done to evaluate any significant differences. RESULTS: A total of 394 patients (median age, 48.5 years) from 124 papers were included in the study; 31% of the study population was male and 69% was female. Indication for interruption was OBG related in 53.3%, vascular surgery related in 25.1%, oncology related in 17.5%, and trauma related in 4.1% of patients. Overall ischemic complication rate was 22.6%, comprising buttock claudication in 12.2%, buttock necrosis in 4.8%, erectile dysfunction in 2.7%, spinal cord ischemia in 4.0%, colonic ischemia in 2.5%, and bladder necrosis in 0.8%. Complications were fewer in patients younger than the median age of 48.5 years (12.8%) compared with those older than the median age (36.3%; P < .01), women compared with men (13.1% vs 41.7%; P < .01), OBG patients compared with vascular surgery patients (9.5% vs 37.4%; P < .01), patients after ligation compared with embolization (9.4% vs 31.0%; P < .01), and proximal interruption compared with distal interruption (19.6% vs 51.4%; P < .01). No significant difference in complications was seen after bilateral interruption compared with unilateral interruption (20.6% vs 27.1%; P > .05). Similarly, no significant difference in complication rate was seen with the type of embolization material used. Among OBG patients, ligations resulted in fewer complications compared with embolization (4.1% vs 16.7%; P < .01). Among vascular surgery patients, bilateral embolization resulted in a higher rate of complications compared with bilateral ligation (83.3% vs 30.5%; P < .01). Among oncology patients, fewer complications were seen after proximal interruption compared with distal interruption (25.5% vs 75%; P = .01). No significant differences in outcome were seen with regard to gender, laterality, and material used for embolization when patients were compared within each specialty. CONCLUSIONS: Interruption of the hypogastric artery is relatively safe in young and OBG patients compared with vascular surgery and oncology patients. Ligation of the hypogastric arteries is preferred to embolization, and proximal embolization should be preferred to distal embolization to decrease the risk of ischemic complications. Randomized controlled trials with larger sample size are needed to definitively elucidate clear risk factors for development of complications after hypogastric artery interruption.