Reassessing the operative threshold for abdominal aortic aneurysm repair in the context of COVID-19.

OBJECTIVE: The worldwide pandemic involving the novel respiratory syndrome (COVID-19) has forced health care systems to delay elective operations, including abdominal aortic aneurysm (AAA) repair, to conserve resources. This study provides a structured analysis of the decision to delay AAA repair and quantify the potential for harm. METHODS: A decision tree was constructed modeling immediate repair of AAA relative to an initial nonoperative (delayed repair) approach. Risks of COVID-19 contraction and mortality, aneurysm rupture, and operative mortality were considered. A deterministic sensitivity analysis for a range of patient ages (50 to >80), probability of COVID-19 infection (0.01%-30%), aneurysm size (5.5 to >7 cm), and time horizons (3-9 months) was performed. Probabilistic sensitivity analyses were conducted for three representative ages (60, 70, and 80). Analyses were conducted for endovascular aortic aneurysm repair (EVAR) and open surgical repair (OSR). RESULTS: Patients with aneurysms 7 cm or greater demonstrated a higher probability of survival when treated with immediate EVAR or OSR, compared with delayed repair, for patients under 80 years of age. When considering EVAR for aneurysms 5.5 to 6.9 cm, immediate repair had a higher probability of survival except in settings with a high probability of COVID-19 infection (10%-30%) and advanced age (70-85+ years). A nonoperative strategy maximized the probability of survival as patient age or operative risk increased. Probabilistic sensitivity analyses demonstrated that patients with large aneurysms (>7 cm) faced a 5.4% to 7.7% absolute increase in the probability of mortality with a delay of repair of 3 months. Young patients (60-70 years) with aneurysms 6 to 6.9 cm demonstrated an elevated risk of mortality (1.5%-1.9%) with a delay of 3 months. Those with aneurysms 5 to 5.9 cm demonstrated an increased survival with immediate repair in young patients (60); however, this was small in magnitude (0.2%-0.8%). The potential for harm increased as the length of surgical delay increased. For elderly patients requiring OSR, in the context of endemic COVID-19, delay of repair improves the probability of survival. CONCLUSIONS: The decision to delay operative repair of AAA should consider both patient age and local COVID-19 prevalence in addition to aneurysm size. EVAR should be considered when possible due to a reduced risk of harm and lower resource utilization.

Cannabis use disorder and perioperative outcomes in vascular surgery.

BACKGROUND: Heavy cannabis use is known to have an adverse impact on cardiovascular and cerebrovascular outcomes in the general population and in patients presenting for surgery. However, there have been no studies that have focused on patients undergoing vascular surgical procedures. The objective of this study was to determine the perioperative risk of cannabis use disorder (CUD), primarily cardiovascular risk, in perioperative vascular surgery patients. METHODS: Using the National Inpatient Sample from 2006 to 2015, we conducted a retrospective cohort study involving those undergoing one of six elective and emergent vascular surgical procedures (carotid endarterectomy [CEA], infrainguinal bypasses, open abdominal aortic aneurysm repair, aortobifemoral bypass, endovascular aortic aneurysm repair, or peripheral arterial endovascular procedures). Patients with CUD identified by the International Classification of Diseases, 9th edition, were matched with patients without CUD in a 1:1 ratio using propensity scores. The primary outcome was perioperative myocardial infarction (MI). Secondary outcomes include stroke, sepsis, deep vein thrombosis, pulmonary embolus, acute kidney injury requiring dialysis, respiratory failure, in-hospital mortality, total cost, and length of stay. RESULTS: We identified a total cohort of 510,007 patients. Over the study period, the recorded prevalence of CUD increased from 1.3/1000 to 10.3/1000 admissions (P < .001). After propensity score matching the cohort consisted of 4684 patients. Those with CUD had a higher incidence of perioperative MI (3.3% vs 2.1%; odds ratio [OR], 1.56; 95% confidence interval [CI], 1.09-2.24; P = .016) and perioperative stroke (5.5% vs 3.5%; OR, 1.59; 95% CI, 1.20-2.12; P = .0013) than patients without CUD. In a sensitivity analysis, where the risk was evaluated separately by type of procedure, the higher incidence of perioperative stroke was primarily seen among those undergoing CEA. Patients with CUD had a lower incidence of sepsis (3.3% vs 5.1%; OR, 0.64; 95% CI, 0.47-0.85; P = .0024). We obtained similar results in a sensitivity analysis that included all patients in the complete unmatched cohort and adjusted for confounding using logistic regression models accounting for the survey design, although the findings of sepsis and stroke failed to reach statistical significance after correcting for multiple testing (MI P = .001; stroke P = .031; sepsis P = .009). CONCLUSIONS: CUD was associated with a significantly higher incidence of perioperative MI in vascular surgery patients. Those with CUD had a greater incidence of diagnosis of acute perioperative stroke when undergoing CEA. Owing to limitations in administrative data, it is unclear if this represents a true effect or selection bias. These findings warrant further investigation in a prospective cohort.

Cannabis Use Disorder and Perioperative Outcomes in Major Elective Surgeries: A Retrospective Cohort Analysis.

BACKGROUND: Although cannabis is known to have cardiovascular and psychoactive effects, the implications of its use before surgery are currently unknown. The objective of the present study was to determine whether patients with an active cannabis use disorder have an elevated risk of postoperative complications. METHODS: The authors conducted a retrospective population-based cohort study of patients undergoing elective surgery in the United States using the Nationwide Inpatient Sample from 2006 to 2015. A sample of 4,186,622 inpatients 18 to 65 yr of age presenting for 1 of 11 elective surgeries including total knee replacement, total hip replacement, coronary artery bypass graft, caesarian section, cholecystectomy, colectomy, hysterectomy, breast surgery, hernia repair, laminectomy, and other spine surgeries was selected. The principal exposure was an active cannabis use disorder, as defined by International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) diagnostic codes for cannabis dependence and cannabis abuse. The primary outcome was a composite endpoint of in-hospital postoperative myocardial infarction, stroke, sepsis, deep vein thrombosis, pulmonary embolus, acute kidney injury requiring dialysis, respiratory failure, and in-hospital mortality. Secondary outcomes included hospital length of stay, total hospital costs, and the individual components of the composite endpoint. RESULTS: The propensity-score matched-pairs cohort consisted of 27,206 patients. There was no statistically significant difference between patients with (400 of 13,603; 2.9%) and without (415 of 13,603; 3.1%) a reported active cannabis use disorder with regard to the composite perioperative outcome (unadjusted odds ratio = 1.29; 95% CI, 1.17 to 1.42; P < 0.001; Adjusted odds ratio = 0.97; 95% CI, 0.84 to 1.11; P = 0.63). However, the adjusted odds of postoperative myocardial infarction was 1.88 (95% CI, 1.31 to 2.69; P < 0.001) times higher for patients with a reported active cannabis use disorder (89 of 13,603; 0.7%) compared with those without (46 of 13,603; 0.3%) an active cannabis use disorder (unadjusted odds ratio = 2.88; 95% CI, 2.34 to 3.55; P < 0.001). CONCLUSIONS: An active cannabis use disorder is associated with an increased perioperative risk of myocardial infarction.

Use-dependent activation of neuronal Kv1.2 channel complexes.

In excitable cells, ion channels are frequently challenged by repetitive stimuli, and their responses shape cellular behavior by regulating the duration and termination of bursts of action potentials. We have investigated the behavior of Shaker family voltage-gated potassium (Kv) channels subjected to repetitive stimuli, with a particular focus on Kv1.2. Genetic deletion of this subunit results in complete mortality within 2 weeks of birth in mice, highlighting a critical physiological role for Kv1.2. Kv1.2 channels exhibit a unique property described previously as "prepulse potentiation," in which activation by a depolarizing step facilitates activation in a subsequent pulse. In this study, we demonstrate that this property enables Kv1.2 channels to exhibit use-dependent activation during trains of very brief depolarizations. Also, Kv subunits usually assemble into heteromeric channels in the central nervous system, generating diversity of function and sensitivity to signaling mechanisms. We demonstrate that other Kv1 channel types do not exhibit use-dependent activation, but this property is conferred in heteromeric channel complexes containing even a single Kv1.2 subunit. This regulatory mechanism is observed in mammalian cell lines as well as primary cultures of hippocampal neurons. Our findings illustrate that use-dependent activation is a unique property of Kv1.2 that persists in heteromeric channel complexes and may influence function of hippocampal neurons.

Mycotic Abdominal Aortic Aneurysm Secondary to BCG Therapy for Non-muscle Invasive Urothelial Carcinoma of the Bladder.

Bacillus Calmette-Guerin (BCG) therapy for treatment of bladder cancer is a rare cause of Mycobacterium bovis infected aortic aneurysm. Typical presentations have included general malaise, fever, and lower back pain. We present a case with lower back pain and constipation as presenting symptoms, leading to diagnosis of mycotic aneurysm presumed secondary to intravesical BCG therapy. Treatment included open surgical repair with femoral vein grafting and anti-tubercular therapy. This case highlights the importance of a high index of suspicion for less common infectious complications of BCG therapy.

The Association of Cannabis Use Disorder with Acute Limb Ischemia and Critical Limb Ischemia.

OBJECTIVES: Heavy cannabis use has been associated with the development of acute myocardial infarction and stroke. The objective of this study was to determine if heavy, chronic cannabis use is associated with the development of acute limb ischemia (ALI) or critical limb ischemia (CLI). METHODS: We conducted a retrospective cohort study within the National Inpatient Sample (2006-2015). Patients without cannabis use disorder (CUD) were matched to patients with CUD in a 2:1 ratio using propensity scores. Our primary outcomes were incidence of ALI and CLI. Secondary outcomes included incidence of acute mesenteric ischemia (AMI), chronic mesenteric ischemia (CMI), frequency of open or endovascular interventions, length of stay, and total costs. Sensitivity analyses were performed with alternative models, including in the entire unmatched cohort with regression models utilizing survey weights to account for sampling methodology. RESULTS: We identified a cohort of 46,297 857 unmatched patients. Patients with CUD in the unmatched cohort were younger, with less cardiovascular risk factors, but higher rates of smoking and substance abuse. The matched cohort included 824,856 patients with CUD and 1,610,497 controls. Those with CUD had a higher incidence of ALI (OR 1.20 95% CI: 1.04-1.38 P=.016). Following multiple sensitivity analyses, there was no robust association between CLI and CUD. We observed no robust association of CUD with AMI, CMI, procedures performed, frequency of amputation, costs, or total length of stay. CONCLUSIONS: Cannabis use disorder was associated with a significantly higher incidence of admission for acute limb ischemia. CUD was not associated with an increased risk of critical limb ischemia following sensitivity analysis. Given CUD is often seen in younger, less co-morbid patients it provides an important target for intervention in this population.

A Scoping Review on the Use of Antibiotic-Impregnated Beads and Applications to Vascular Surgery.

INTRODUCTION: Surgical site infection (SSI) presents a ubiquitous concern to surgical specialties, especially in the presence of prosthetic material. Antibiotic-impregnated beads present a novel and evolving means to combat this condition. This review aims to analyze the quality of evidence and methods of antibiotic bead use, particularly for application within vascular surgery. METHODS: A systematic scoping review was conducted within Embase, MEDLINE, and the Cochrane Registry of Randomized Controlled Trials. Articles were evaluated by 2 independent reviewers. Level of evidence was evaluated using the Oxford Center for Evidence-Based Medicine Criteria and the Cochrane Risk of Bias Tool for Randomized Controlled Trials. RESULTS: The search yielded 6951 papers, with 275 included for final analysis. Publications increased in frequency from 1978 to the present. The most common formulation was polymethyl methacrylate; however publications on biodegradable formulations, including calcium sulfate beads, have been published with increasing frequency. Most publications had positive conclusions (94.2%); however, the data was mainly subjective and may be prone to publication bias. Only 11 randomized controlled trials were identified and all but one was evaluated to be at a high risk of bias. The most common indication was for osteomyelitis (52%), orthopedic prosthetic infections (20%), and trauma (9%). Within vascular surgery, beads have been used primarily for the treatment of graft infection, with freedom from recurrence rates being reported from 41% to 87.5%. CONCLUSIONS: Antibiotic-impregnated beads provide a means to deliver high doses of antibiotic directly to a surgical site, without the risks of parenteral therapy. There has yet to be significant high-level quality data published on their use. There is a large body of evidence that suggests antibiotic beads may be used in SSIs in high-risk patients, prosthetic infections, and other complex surgical infections. Important potential areas of application in vascular surgery include graft infection, prevention of wound infection in high-risk patients, and diabetic foot infection.

A comparison of duplex ultrasound findings after cyanoacrylate embolization versus endovenous laser ablation of the great saphenous vein.

BACKGROUND: Whereas numerous studies have demonstrated noninferiority of cyanoacrylate embolization (CAE) relative to endovenous laser ablation (EVLA), little is known about the natural history of the vein or the glue that is implanted. This study provides the first description of duplex ultrasound changes of the great saphenous vein (GSV) after CAE relative to EVLA as well as a pragmatic view of outcomes in clinical practice. METHODS: Patients treated with CAE and EVLA at our institution were matched by time of procedure and vein size. GSV diameter was measured at the saphenofemoral junction, midthigh, and knee. Duplex ultrasound imaging was repeated after treatment in the same noninvasive laboratory with an identical protocol. Clinical data were collected by retrospective chart review. RESULTS: Of 481 eligible patients, 119 underwent postoperative duplex ultrasound imaging. Although there was a trend toward decreased vein diameter over time in CAE patients relative to their preoperative vein diameter, this failed to reach statistical significance at the midthigh (P = .32) or at the knee (P = .511). In EVLA patients, as follow-up interval increased, the vein was less frequently visualized on ultrasound at the midthigh (P = .046) and knee (P = .038). At >2 years of follow-up, >80% of EVLA patients had no visible vein segment. Anatomic recurrence was observed in 10.5% of CAE patients and 8.2% of EVLA patients, which was not statistically significantly different (P = .60). The majority of recurrence was observed in the presence of incompetent tributaries. CONCLUSIONS: After CAE of the GSV, our results indicate that the glue cast remains for at least 3 years. Although our results suggest that the glue is broken down over time, this process is much slower than expected. In contrast, after EVLA, the vein tissue is remodeled and is no longer visible with time. In our study, which represents a pragmatic clinical population with a large (median, 9.2 mm) vein diameter, we again demonstrate no statistically significant difference in recurrence rates. Whereas CAE offers an attractive treatment option for GSV incompetence, the glue cast remains for a prolonged time, and longer follow-up studies than those currently available are indicated.

Safety of Propofol versus Nonpropofol-Based Sedation in Children Undergoing Gastrointestinal Endoscopy: A Systematic Review and Meta-Analysis.

BACKGROUND: The majority of children who undergo gastrointestinal (GI) endoscopy require anesthesia or procedural sedation for comfort, cooperation, and procedure efficiency. The safety profile of propofol is not well established in children but has been studied in the literature. OBJECTIVE: The aim of this study is to evaluate and compare the safety of propofol-only sedation for GI endoscopy procedures to other anesthetic regimes in the pediatric population. METHODS: A search was conducted in the MEDLINE, Embase, and Cochrane Library databases. Randomized clinical trials and prospective cohorts were included in the study. RESULTS: No significant difference was noted in total complications between the two cohorts with a pooled OR of 1.31 (95% CI: 0.57-3.04, chi2 = 0.053, I2 = 54.31%). The pooled rate of complications in the studies was 23.4% for those receiving propofol only and 18.2% for those receiving other anesthetic regimens. Sensitivity analysis was performed removing a study with a very different control comparison compared to the rest of the studies included. Once excluded, there was minimal heterogeneity in the remaining studies and a significant difference in overall complications was detected, with more complications seen in the propofol-only group compared to the other anesthetic groups (OR 1.87, 95% CI 1.09-3.20). CONCLUSION: Significantly higher incidence of cardiorespiratory complications was noted in the propofol-only versus other anesthetic regimens in pediatric patients undergoing GI endoscopy in this meta-analysis. However, the overall quality of the evidence is very low. HOW TO APPLY THIS KNOWLEDGE FOR ROUTINE CLINICAL PRACTICE: Clinicians providing sedation to a pediatric population for GI endoscopy should consider there may be increased risks when using a propofol-only regimen, but further study is needed.