Medicinal cannabis use among young adults during California's transition from legalized medical use to adult-use: a longitudinal analysis.

Background: In 2016, California transitioned from legalized medical cannabis use to adult-use. Little is known about how this policy change affected medicinal cannabis use among young adults.Objectives: To identify longitudinal groups of medicinal cannabis users and concurrent changes in health- and cannabis use-related characteristics among young adults in Los Angeles between 2014 and 2021.Methods: Cannabis users (210 patients and 156 non-patients; 34% female; ages 18-26 at baseline) were surveyed annually across six waves. Longitudinal latent class analysis derived groups from two factors - cannabis patient status and self-reported medicinal use. Trajectories of health symptoms, cannabis use motives, and cannabis use (daily/near daily use, concentrate use, and problematic use) were estimated across groups.Results: Three longitudinal latent classes emerged: Recreational Users (39.3%) - low self-reported medicinal use and low-to-decreasing patient status; Recreational Patients (40.4%) - low self-reported medicinal use and high-to-decreasing patient status; Medicinal Patients (20.3%) - high self-reported medicinal use and high-to-decreasing patient status. At baseline, Medicinal Patients had higher levels of physical health symptoms and motives than recreational groups (p < .05); both patient groups reported higher level of daily/near daily and concentrate use (p < .01). Over time, mental health symptoms increased in recreational groups (p < .05) and problematic cannabis use increased among Recreational Patients (p < .01).Conclusions: During the transition to legalized adult-use, patterns of medicinal cannabis use varied among young adults. Clinicians should monitor increases in mental health symptoms and cannabis-related problems among young adults who report recreational - but not medicinal - cannabis use.

Mental and Physical Health-Related Cannabis Motives Mediate the Relationship between Childhood Trauma and Problematic Cannabis Use over Time among Emerging Adult Cannabis Users.

BACKGROUND: While growing evidence has identified mental and physical health-related cannabis use motives as significant mechanisms between childhood trauma and problematic cannabis use (PCU) for emerging adults (EA), there is a need to understand the longitudinal stability of these pathways and how they impact PCU as cannabis users age into later adulthood. METHODS: The current study extends an analysis examining the impact of childhood trauma (e.g., emotional abuse, sexual abuse) on multiple indicators of PCU through a range of cannabis use motives. 339 medical cannabis patient and non-patient EA users from the Los Angeles area were sampled at baseline (mean age = 21.23; SD = 2.48). The present analysis used four waves of follow-up data collected from 2016 to 2018 (W3, W4) and 2019-2020 (W5, W6). RESULTS: Use of cannabis to cope with nausea, sleep, pain, and emotional distress mediated the relationships between some types of childhood abuse and PCU at W4, though most associations attenuated by later adulthood (W6). Specifically, greater emotional distress and nausea motives were associated with greater PCU in models of emotional abuse and neglect and sexual abuse, with emotional distress continuing to mediate at W6. Conversely, sleep and pain motives were associated with lower PCU in models for emotional neglect. CONCLUSIONS: Mental and physical health-related motives reflect potential intervenable factors that predict PCU in emerging adulthood among EA cannabis users with histories of childhood trauma. Results highlight the importance of and value for assessing a wide range of motives and PCU outcomes to target and address areas for intervention.

Investigation of NO Role in Neural Tissue in Brain and Spinal Cord Injury.

Nitric oxide (NO) production in injured and intact brain regions was compared by EPR spectroscopy in a model of brain and spinal cord injury in Wistar rats. The precentral gyrus of the brain was injured, followed by the spinal cord at the level of the first lumbar vertebra. Seven days after brain injury, a reduction in NO content of 84% in injured brain regions and 66% in intact brain regions was found. The difference in NO production in injured and uninjured brain regions persisted 7 days after injury. The copper content in the brain remained unchanged one week after modeling of brain and spinal cord injury. The data obtained in the experiments help to explain the problems in the therapy of patients with combined brain injury.

COVID-19 Vaccine Uptake and Attitudes Within Two Cohorts of Younger Adult Cannabis Users.

It is crucial to understand COVID-19 vaccine uptake and attitudes among young adult cannabis users given the lowest vaccination rates among young adults and negative association between cannabis use and willingness to get vaccinated. 18-21-year-old and 26-33-year-old cohorts of cannabis users, recruited in California, were surveyed about the COVID-19 vaccine uptake/attitudes between March-August 2021. Cannabis use/demographic differences were investigated by vaccination status. Vaccine attitudes data were categorized and presented descriptively. 44.4% of the older and 71.8% of the younger cohorts were vaccinated. Non-Hispanic Black/African American race/ethnicity, lack of health insurance, and medicinal orientation towards cannabis use were negatively associated with vaccine receipt within the older cohort. For both cohorts, top reasons for vaccine hesitancy and rejection were concerns about speed of development, potential side effects, natural immunity, and lack of trust of vaccines. Our results highlight greater vaccine hesitance/rejection and need for targeted interventions among mid-20's-early-30's cannabis users.

Association of preoperative vein mapping with hemodialysis access characteristics and outcomes in the Vascular Quality Initiative.

BACKGROUND: Preoperative vein mapping before arteriovenous fistula (AVF) or arteriovenous graft (AVG) placement has been debated as a possible method of improving hemodialysis access outcomes for patients. However, high-quality national studies that have addressed this relationship are lacking. Thus, we assessed the association of preoperative vein mapping with hemodialysis access configuration and outcomes. METHODS: In the present cohort study, we analyzed all patients who had undergone AVF or AVG placement with data captured in the Vascular Quality Initiative hemodialysis access dataset from August 2011 to September 2019. The patients were stratified by whether they had undergone preoperative vein mapping. The primary (configuration) outcomes were access type (AVF vs AVG) and location (upper arm vs forearm). The secondary (longitudinal) outcomes were the successful initiation of hemodialysis, maintenance of secondary patency, and the need for reintervention 1 year after the index operation. RESULTS: Overall, 85.6% of the 46,010 included patients had undergone preoperative vein mapping. Of the 46,010 patients, 76.1% and 23.9% had undergone AVF and AVG creation, respectively. AVF creation (77.6% vs 67.3%) and forearm location (54.6% vs 47.3%) were more frequent for the patients who had undergone preoperative vein mapping than for those who had not (P < .001). After adjusting for baseline differences between the groups, preoperative vein mapping was associated with increased odds of receiving an AVF vs AVG (adjusted odds ratio, 1.64; 95% confidence interval [CI], 1.55-1.75) and forearm vs upper arm access (adjusted odds ratio, 1.22; 95% CI, 1.16-1.30). The incidence of the loss of secondary patency was lower for patients with preoperative vein mapping (P < .001), and persisted after risk adjustment (adjusted hazard ratio, 0.81; 95% CI, 0.75-0.88). CONCLUSIONS: Preoperative vein mapping was associated with favorable hemodialysis access configurations and outcomes in real-world practice. These data suggest that the use of preoperative vein mapping could improve the likelihood of favorable outcomes for patients requiring hemodialysis access.

COVID-19's Impact on Substance Use and Well-Being of Younger Adult Cannabis Users in California: A Mixed Methods Inquiry.

Few qualitative studies have examined the impact of COVID-19 on cannabis and alcohol use, and overall well-being among cannabis users. Cannabis users (aged 26-32) were surveyed quantitatively (n=158) and interviewed qualitatively (n=29) in April 2020-May 2021 in Los Angeles. 63.3% of the quantitative sample reported increasing use of either cannabis (29.1%) or alcohol (15.2%) or both (19.0%) following the COVID-19 outbreak. Qualitative data revealed that increases in cannabis and alcohol use were largely attributed to changes in employment and staying at home resulting in fewer impediments and boredom. Themes of loneliness and utilization of various coping strategies were more pronounced among those who increased cannabis and/or alcohol use. For some, increases in cannabis/alcohol use were temporary until participants adjusted to "a new normal" or embraced more adaptive coping strategies. Results suggest monitoring cannabis/alcohol use trends and identifying coping strategies to reduce the pandemic's impact on substance use and mental health.

Pain Profiles among Young Adult Cannabis Users: An Analysis of Antecedent Factors and Distal Outcomes.

BACKGROUND: Pain is a primary reason for medical cannabis use among young adults, however little is known about the patterns of pain in this group. This study identified pain profiles among young adult cannabis users and examined related antecedents and distal outcomes. METHODS: Past 30-day cannabis users aged 18-26, both medical cannabis patients and non-patients, were enrolled in Los Angeles in 2014-2015. A latent class analysis was used to identify pain classes based on history of chronic pain conditions and recent non-minor pain. The study assessed the predictors of membership in pain classes and examined the association of classes with recent mental health characteristics, cannabis use motives and practices. RESULTS: Three classes were identified: Low pain (56.3%), Multiple pain (27.3%), and Nonspecific pain (16.4%). In adjusted models, lifetime insomnia was associated with membership in Multiple pain and Nonspecific pain classes versus the Low pain class. Medical cannabis patients and Hispanics/Latinos were more likely to belong to the Multiple pain class than the other classes. Regarding recent outcomes, the Multiple pain and Nonspecific pain classes were more likely than the Low pain class to use cannabis to relieve physical pain. Additionally, the Multiple pain class had a higher probability of psychological distress, self-reported medical cannabis use, consuming edibles, and using cannabis to sleep compared to one or both other classes. CONCLUSION: Findings suggest that young adult cannabis users can be separated into distinct groups with different pain profiles. The Multiple pain profile was associated with medically-oriented cannabis use motives and practices.

The Role of Life Events/Contextual Factors and Cannabis Use in Patterns of Other Drug Use Among Young Adult Cannabis Users in Los Angeles: A Qualitative Inquiry.

This analysis examined the role of impactful life events/stressful contextual factors and cannabis use in the patterns of illicit drug use. It utilized semi-structured qualitative interviews with 40 young adult medical cannabis patients and 22 non-patient users collected in Los Angeles during 2014-2015. Three patterns of illicit drug use emerged based on participants' narratives: regular/problematic, recreational/occasional, and never users. Among regular/problematic users, a common theme was the lasting impact of traumatic life events or stressful contextual factors on transition to and away from problematic drug use, and using cannabis to cope with negative after effects of drug use. In contrast, most recreational/occasional and never users, who reported impactful life events or stressful contextual factors, used cannabis to cope with those experiences. Family history of addiction and acceptance of cannabis use within a family as protective factors against illicit drug use among some recreational/occasional and never users was an unexpected finding.

Marijuana sources in a medical marijuana environment: dynamics in access and use among a cohort of young adults in Los Angeles, California.

While a range of sources exist for marijuana users to acquire marijuana for medical or personal use, prior research on marijuana sources primarily focused on single sources. In this analysis, we longitudinally examined characteristics of multiple sources selected by marijuana users, motivations to use sources, and how a blend of marijuana sources accommodated users' needs. Young adult marijuana users (n=60) in Los Angeles, CA, where marijuana has been legal for medical use since 1996, completed two annual qualitative interviews on marijuana use practices and sources between 2014 and 2016. Approximately two-thirds were medical marijuana patients and one-third were non-patient users. Participants reported acquiring marijuana from the following primary sources across two interviews: dispensaries and delivery services, private sellers in the illicit market, friends and family, and marijuana events/conferences. While patients with legal medical access to marijuana typically purchased marijuana from dispensaries or delivery services, they often supplemented from other illicit sources. Non-patients often accessed marijuana through dispensary diversion but also other sources. As patients became non-patients and vice versa during the study period, source type changed too. Broad access to marijuana via legal and illicit sources in this sample is indicative of societal trends towards normalization of marijuana use.

Pharmacies as providers of expanded health services for people who inject drugs: a review of laws, policies, and barriers in six countries.

BACKGROUND: People who inject drugs (PWID) are underserved by health providers but pharmacies may be their most accessible care settings. METHODS: Studies in the U.S., Russia, Vietnam, China, Canada and Mexico employed a three-level (macro-, meso-, and micro-) model to assess feasibility of expanded pharmacy services for PWID. Studies employed qualitative and quantitative interviews, review of legal and policy documents, and information on the knowledge, attitudes, and practices of key stakeholders. RESULTS: Studies produced a mixed assessment of feasibility. Provision of information and referrals by pharmacies is permissible in all study sites and sale and safe disposal of needles/syringes by pharmacies is legal in almost all sites, although needle/syringe sales face challenges related to attitudes and practices of pharmacists, police, and other actors. Pharmacy provision of HIV testing, hepatitis vaccination, opioid substitution treatment, provision of naloxone for drug overdose, and abscess treatment, face more serious legal and policy barriers. DISCUSSION: Challenges to expanded services for drug users in pharmacies exist at all three levels, especially the macro-level characterized by legal barriers and persistent stigmatization of PWID. Where deficiencies in laws, policies, and community attitudes block implementation, stakeholders should advocate for needed legal and policy changes and work to address community stigma and resistance. Laws and policies are only as good as their implementation, so attention is also needed to meso- and micro- levels. Policies, attitudes, and practices of police departments and pharmacy chains as well as knowledge, attitudes, and practices of individual PWID, individual pharmacies, and police officers should support rather than undermine positive laws and expanded services. Despite the challenges, pharmacies remain potentially important venues for delivering health services to PWID.

Access to syringes for HIV prevention for injection drug users in St. Petersburg, Russia: syringe purchase test study.

BACKGROUND: The HIV epidemic in Russia is concentrated among injection drug users (IDUs). This is especially true for St. Petersburg where high HIV incidence persists among the city's estimated 80,000 IDUs. Although sterile syringes are legally available, access for IDUs may be hampered. To explore the feasibility of using pharmacies to expand syringe access and provide other prevention services to IDUs, we investigated the current access to sterile syringes at the pharmacies and the correlation between pharmacy density and HIV prevalence in St. Petersburg. METHODS: 965 pharmacies citywide were mapped, classified by ownership type, and the association between pharmacy density and HIV prevalence at the district level was tested. We selected two districts among the 18 districts--one central and one peripheral--that represented two major types of city districts and contacted all operating pharmacies by phone to inquire if they stocked syringes and obtained details about their stock. Qualitative interviews with 26 IDUs provided data regarding syringe access in pharmacies and were used to formulate hypotheses for the pharmacy syringe purchase test wherein research staff attempted to purchase syringes in all pharmacies in the two districts. RESULTS: No correlation was found between the density of pharmacies and HIV prevalence at the district level. Of 108 operating pharmacies, 38 (35%) did not sell syringes of the types used by IDUs; of these, half stocked but refused to sell syringes to research staff, and the other half did not stock syringes at all. Overall 70 (65%) of the pharmacies did sell syringes; of these, 49 pharmacies sold single syringes without any restrictions and 21 offered packages of ten. CONCLUSIONS: Trainings for pharmacists need to be conducted to reduce negative attitudes towards IDUs and increase pharmacists' willingness to sell syringes. At a structural level, access to safe injection supplies for IDUs could be increased by including syringes in the federal list of mandatory medical products sold by pharmacies.

Understanding Changes in Social Cannabis Use among Young Adults During the COVID-19 Pandemic: A Social Network Analysis.

Introduction: As the COVID-19 pandemic has caused historic morbidity and mortality and disrupted young people's social relationships, little is known regarding change in young adults' social cannabis use following social distancing orders, or other factors associated with such changes before and during the pandemic. Methods: 108 young adult cannabis users in Los Angeles reported on their personal (egocentric) social network characteristics, cannabis use, and pandemic-related variables before (July 2019 - March 2020) and during the COVID-19 pandemic (August 2020 - August 2021). Multinomial logistic regression identified factors associated with increasing or maintaining the number of network members (alters) participants used cannabis with before and during the pandemic. Multilevel modeling identified ego- and alter-level factors associated with dyadic cannabis use between each ego and alter during the pandemic. Results: Most participants (61%) decreased the number of alters they used cannabis with, 14% maintained, and 25% increased. Larger networks were associated with a lower risk of increasing (vs. decreasing); more supportive cannabis-using alters was associated with a lower risk of maintaining (vs. decreasing); relationship duration was associated with a greater risk of maintaining and increasing (vs. decreasing). During the COVID-19 pandemic (August 2020 - August 2021), participants were more likely to use cannabis with alters they also used alcohol with and alters who were perceived to have more positive attitudes towards cannabis. Conclusions: The present study identifies significant factors associated with changes in young adults' social cannabis use following pandemic-related social distancing. These findings may inform social network interventions for young adults who use cannabis with their network members amid such social restrictions.

Pre-Post Cannabis Legalization for Adult Use: A Trend Study of Two Cohorts of Young Adult Cannabis Users in Los Angeles.

Cannabis was legalized for adult use in California in 2016 for individuals 21 and older. Among 18-20-years-olds, who can possess cannabis legally as medical cannabis patients (MCP) but not as non-patient cannabis users (NPU), the impact of adult use legalization (AUL) on cannabis and other substance use is unknown. Two cohorts of 18-20-year-old cannabis users (MCP and NPU) were surveyed, one in 2014-15 (n = 172 "pre-AUL") and another in 2019-20 (n = 139 "post-AUL"), using similar data collection methods in Los Angeles, California. Logistic and negative binomial regressions estimated cohort and MCP differences for cannabis and other drug use outcomes based on past 90-day use. In both pre- and post-AUL cohorts, MCP were more likely to self-report medical cannabis use (p < .001) while the post-AUL cohort reported greater use of edibles (p < .01), but fewer mean days of alcohol (p < .05) and cigarette (p < .01) use in multivariate models. Notably, frequency of cannabis use (days or hits per day) did not significantly differ between the pre- and post-AUL cohorts, except for greater use of edibles, despite potentially greater access to cannabis.

Egocentric Network Characteristics and Cannabis Use in a Sample of Young Adult Medical Cannabis Patients and Nonpatient Users.

OBJECTIVE: Social factors play an important role in young adults' substance use behaviors, but little is known about how egocentric social network factors are related to young adults' cannabis use. Young adults also report medicinal and recreational uses of cannabis, which may alter the strength of these relationships. Therefore, medical cannabis patient status and medicinal/recreational orientation toward cannabis were examined as moderators of these relationships. METHOD: Young adult medical cannabis patients (n = 182) and nonpatient users (n = 157) were surveyed in Los Angeles in 2015-2016 about their cannabis use, orientation (medicinal and/or recreational), and egocentric networks (cannabis use network size, social support network size, descriptive and injunctive norms). Regression models examined associations between network characteristics and past-90-day use and problematic use, and tested interactions between network characteristics and both patient status and cannabis use orientation. RESULTS: Only descriptive norms (adjusted incidence rate ratio [aIRR] = 1.19, 95% confidence interval [CI] [1.06, 1.33]) were associated with more frequent use, but not problematic use. Descriptive norms interacted with cannabis use orientation: descriptive norms were positively associated with cannabis use days among medicinally oriented users (aIRR = 1.22, 95% CI [1.02, 1.46]). However, this relationship was stronger for recreationally oriented users (aIRR = 1.62, 95% CI [1.31, 2.01]). No interactions were found predicting problematic use. CONCLUSIONS: Descriptive cannabis use norms among one's personal network members are an important variable predicting young adults' cannabis use, but not problematic use. Perceived descriptive norms may be a stronger motivator to use for recreational users than medicinal users.

Changes in Medical Cannabis Patient Status before and after Cannabis Legalization in California: Associations with Cannabis and Other Drug Use.

It is unknown how patterns of cannabis and other drug use changed among young adult cannabis users as they became, exited or stayed medical cannabis patients (MCPs) after California legalized cannabis for adult use in 2016. A cohort of 18-26 year-old cannabis users was recruited in Los Angeles in 2014-15 (64.8% male; 44.1% Hispanic/Latinx). Based on wave 1 (pre-legalization) and wave 4 (post-legalization) MCP status, four transition groups emerged: MCP, Into MCP, Out of MCP and NPU (non-patient user). Relationships between self-reported medical cannabis use, transition group membership, and cannabis/other drug use outcomes were examined. Changes in cannabis practices were consistent with changes in MCP status. Cannabis days, concentrate use, self-reported medical cannabis use and driving under influence of cannabis were highest among MCP, increased for Into MCP, and decreased for Out of MCP in wave 4. A majority of drug use outcomes decreased significantly by wave 4. Self-reported medical cannabis use was associated with more frequent cannabis use but less problematic cannabis and other drug use. Future studies should continue to monitor the impact of policies that legalize cannabis for medical or recreational use, and medical motivations for cannabis use on young adults' cannabis and other drug use.

Antireflux and Endoscopic Therapies for Barrett Esophagus and Superficial Esophageal Neoplasia.

Barrett esophagus (BE), defined as intestinal metaplasia of the distal esophageal mucosa, typically results from chronic gastroesophageal reflux disease and is the only known precursor of esophageal adenocarcinoma. The standard of care for the management of early esophageal neoplasia in the setting of BE has changed drastically over the past 15 years. Further investigation into diagnostic and therapeutic adjuncts will continue to improve our ability to control or cure BE before its advancement to a life-threatening malignancy.

Cannabidiol (CBD) and other drug use among young adults who use cannabis in Los Angeles.

INTRODUCTION: Cannabidiol (CBD) is purportedly a promising therapeutic agent to provide relief for a variety of medical conditions with mild or no psychoactive effects. However, little is known about young adults who use cannabis and CBD-dominant products, and associations between CBD use and other drug use. METHODS: Young adults (aged 24-32) who currently used cannabis (n = 239) were surveyed in Los Angeles in March 2019 through March 2020. The sample was divided into CBD-dominant (at least 1:1 CBD:THC ratio) and THC-dominant product users. We described CBD forms, reasons and conditions for CBD use and examined between-group differences in sociodemographic characteristics, cannabis practices, health and other drug use. RESULTS: CBD-dominant users were more likely to be female, use cannabis at lower frequency and amount (except for edible/drinkable/oral products), self-report medical motivation for cannabis use, use cannabis for pain and report more health problems. Oil, flower, topicals and sprays/drops/tinctures were the most prevalent CBD forms. Psychological problems and pain were commonly reported conditions and medical reasons for CBD use. CBD-dominant users were more likely to report illicit drug use, where psilocybin use was markedly different between the two groups. CONCLUSIONS: CBD use was associated with health histories and motivations linked to pain and psychological problems. Positive association between CBD use and illicit drug use may indicate self-medication for psychological conditions. Future studies should evaluate the effectiveness of various CBD forms and dose regimens for treatment of pain and psychological problems, and as a potential intervention for decreasing other drug use and associated harms.

Evaluation of the C60 biodistribution in mice in a micellar ExtraOx form and in an oil solution.

The article is devoted to the study of the pharmacokinetics of fullerene C60 in oil and micellar forms, analysis of its content in blood, liver, lungs, kidneys, heart, brain, adrenal glands, thymus, testicles, and spleen. The highest accumulation of C60 was found in the liver and adrenal glands. As a result of the studies carried out, it was shown that the bioavailability of C60 in the micellar form is higher than that in an oil solution.

Developmental trajectories of illicit drug use, prescription drug misuse and cannabis practices among young adult cannabis users in Los Angeles.

INTRODUCTION AND AIMS: Young adults have the highest rates of drug use and contribute significantly to the growing population of medical cannabis patients (MCP). This study examined relationships between longitudinal patterns of illicit/prescription drug use/misuse and cannabis practices among young adult cannabis users. DESIGN AND METHODS: In 2014-2015, 210 young adult MCP and 156 nonpatient users were recruited in Los Angeles and surveyed annually over four waves. The analytical sample was limited to completers of all four waves (n = 301). Distinct developmental trajectories of illicit drug use and prescription drug misuse were identified. Fixed effects regression analysis evaluated changes in cannabis practices by trajectory groups. RESULTS: Results supported two-trajectory solutions (high/low) for illicit drug use and prescription drug misuse. Decreases in use within all four trajectories occurred by wave 4. Low illicit drug use trajectory members were more likely to self-report medical cannabis use. Membership in both types of high-use trajectories was associated with use of concentrates and edibles. The prevalence of MCP, edibles use and cannabis days decreased significantly by wave 4. DISCUSSION AND CONCLUSIONS: While alternative cannabis forms use was associated with membership in high drug use trajectories, self-reported medical cannabis use (not MCP) was negatively associated with high illicit drug use trajectory membership. Reductions in the prevalence of MCP, cannabis days, edibles use and other drug use by wave 4 alongside stable levels of self-reported medical cannabis use might reflect the changing legal status of cannabis in California, maturing out phenomenon and safer patterns of cannabis use.

Thromboembolic Events with Enterprise Versus Pipeline: Porcine In Vivo Experiment.

BACKGROUND: Thromboembolic complications are serious adverse events associated with stenting of intracranial aneurysms. For the development of novel devices, currently no practical model exists to evaluate distal embolic events. The purpose of the current study was 2-fold: 1) assess the feasibility of a porcine carotid bifurcation model for in vivo testing of stent thrombogenicity and 2) compare the thrombogenicity of the Enterprise vascular reconstruction device versus the Pipeline embolization device (PED). METHODS: Six Yorkshire pigs underwent implantation of size-matched devices across the carotid bifurcation. Each animal received 1 Enterprise and 1 PED contralaterally. Baseline and 2-week follow-up angiography were performed. Images were analyzed including detailed measurements of the rete mirabile, a small-vessel conglomerate supplied by branches of the common carotid artery. RESULTS: In the absence of thromboembolic events at 2 weeks (n = 8), the perfused rete area measured 134.4 ± 6.9 mm2. In the presence of thromboembolic events (n = 4), the perfused rete was reduced to an area covering 37.1 ± 8.6 mm2 (P < 0.01). There was no difference in thrombogenicity between Enterprise and PED with a thromboembolic event rate of 33.3% for both devices (P > 0.99). CONCLUSION: The swine carotid stent model allows in vivo analysis of device-related thrombogenicity and distal embolic event rates. Size reduction of the perfused rete mirabile indicates the presence of thromboembolic events. Both Enterprise and PED were associated with similar thrombogenicity in this experiment.