Stenting of a hepatic artery pseudoaneurysm rupture secondary to a celiac artery dissection

Hepatic artery (HA) pseudoaneurysm rupture is a rare and potentially lethal pathology. We present the case of a celiac artery dissection complicated by an HA pseudoaneurysm rupture that was treated successfully with endovascular stenting. The patient's postoperative course was uncomplicated, and he was further evaluated for an underlying connective tissue disorder. There is no standard treatment for a ruptured HA pseudoaneurysm, although transarterial embolization is most frequently reported. This report demonstrates that self-expanding stent grafts are effective in the emergent repair of HA pseudoaneurysm rupture.

Multi-institutional patterns of clopidogrel response among patients undergoing transcarotid artery revascularization

OBJECTIVE

Current guidelines recommend dual antiplatelet therapy (DAPT) in patients undergoing carotid artery stenting. The most common DAPT regimen is aspirin and clopidogrel, a P2Y12 receptor antagonist; however, the prevalence of clopidogrel resistance (CR) in patients undergoing percutaneous coronary interventions may exceed 60%. Few studies have investigated the prevalence and impact of CR in patients undergoing extracranial carotid artery stenting, particularly transcarotid artery revascularization (TCAR).

METHODS

Consecutive high-risk patients ≥ 18 years who underwent TCAR for high grade (≥70%) and/or symptomatic (≥50%) carotid stenosis with preoperative P2Y12 testing between August 2019 and December 2021 were identified across five institutions. Preoperative platelet reactivity was measured with the VerifyNow P2Y12 Reaction Unit (PRU) Test (Instrumentation Laboratory, Bedford, MA), with CR defined as PRU ≥ 194 and hyper-response as PRU <70. Patients without preoperative P2Y12 testing within 30 days prior to TCAR or those on a non-clopidogrel P2Y12 inhibitor preoperatively were excluded. The primary outcome of interest was prevalence of CR. Secondary outcomes of interest included the incidence of ischemic and hemorrhagic complications.

RESULTS

Of 92 patients identified, the majority were male (59%) and Caucasian (75%) with a mean age of 75 years (±8, range 56-92). Preoperatively, 93% of patients were on aspirin, 100% on clopidogrel, and 13% on therapeutic anticoagulation. At presentation, 36% were symptomatic. The mean preoperative P2Y12 was 156 PRU (±76, range 6-349). In total, 30 (33%) patients met criteria for CR (mean PRU 240 ± 37; range 197-349), and 15 (16%) met criteria for hyper-responder (mean PRU 38 ± 20; range 6-68). There was no significant difference by clopidogrel response phenotype in terms of sex (p = 0.246), race (p = 0.384), or symptomatic presentation (p = 0.956). Postoperatively, the cumulative incidence of stroke and MI was 2.1%, with no statistically significant difference in the incidence of in-hospital stroke (PRU 238, p = 0.489) or MI (PRU 168, p = 1) between clopidogrel phenotypes. Three (3.3%) patients, one CR (PRU 240) and two responders (PRU 119 and PRU 189), experienced postoperative access site hematomas that required no subsequent intervention. No other index hospitalization hemorrhagic complications occurred.

CONCLUSIONS

Using preoperative P2Y12 testing with a threshold PRU ≥ 194 to define CR, we identified a high prevalence of CR in patients undergoing TCAR similar to that in the pre-existing coronary literature. We found no significant differences in postoperative ischemic or hemorrhagic complications by clopidogrel response phenotype, although complication rates in the overall study cohort were low. CR may be a spectrum from responder to partial responder to complete non-responder, and this may account for the differences in our CR cohort compared to the ROADSTER 2 protocol deviation cohort. Further investigation is warranted to determine if a quantitative assessment of CR is sufficient to identify patients at risk of developing secondary cerebrovascular ischemic events in this patient population.

Implementation of a Vascular Acute Care Surgery Service Model is Associated with Decreased Surgeon Burnout

Vascular surgeons have one of the highest rates of burnout among surgical specialties, often attributed to high patient acuity and clinical workload. Acute Care Surgery (ACS) models are a potential solution used among general and trauma surgeons. This is a retrospective analysis of prospectively collected Accreditation Council for Graduate Medical Education (ACGME) survey results from faculty and residents before and after implementation of a vascular ACS (VACS) model. The VACS model assigns a weekly rotation of an attending surgeon with no elective cases or clinic responsibilities and a monthly rotating resident team. Residents and attendings are in-house to cover all urgent and emergent vascular daytime consultations and procedures, while nights and weekend coverage remain a typical rotating schedule. Survey question results were binned into domains consistent with the Maslach Burnout Inventory (MBI). Both residents and faculty reported an increase in median scores in MBI domains of Emotional Exhaustion (Faculty:2.9 vs. 3.4, p<0.001; Residents:3.1 vs. 3.6, p<0.001) and faculty reported higher Personal Accomplishment scores (Faculty:3.3 vs. 3.8, p=0.005) after the VACS model implementation. A VACS model is a tangible practice change that can address a major problem for current vascular surgeons as it is associated with decreased burnout for faculty and residents through improvement in both emotional exhaustion and personal accomplishment. Improved longitudinal assessment of resident and faculty burnout is needed and future work should identify specific practice patterns related to decreased burnout.

A registry-based study of paclitaxel drug-coated balloon angioplasty for the treatment of in-stent restenosis of the femoral-popliteal artery

OBJECTIVE

The aim of this study was to report the results of a prospective, single-arm, registry-based study assessing the safety and performance of a paclitaxel drug-coated balloon (DCB) for the treatment of superficial femoral artery (SFA) or popliteal artery in-stent restenosis (ISR) in a United States population.

METHODS

We conducted a prospective, non-randomized, multi-center, single-arm, post-market registry of the IN.PACT Admiral DCB for the treatment of ISR lesions in the SFA or popliteal artery at 43 sites within the Society for Vascular Surgery (SVS) Vascular Quality Initiative (VQI) Registry from December 2016 to January 2020. Clinical outcomes were assessed at 12, 24, and 36 months. The primary endpoint was target lesion revascularization at 12 months. Secondary endpoints included technical success, target vessel revascularization, major limb amputation, and all-cause mortality. Results are presented as survival probabilities based on Kaplan-Meier survival estimates.

RESULTS

Patients (N = 300) were 58% male, with a mean age of 68 ± 10 years. Diabetes was present in 56%, 80% presented with claudication, and 20% with rest pain. Lesions included ISR of the SFA in 68%, SFA-popliteal in 26%, and popliteal arteries in 7%. The mean lesion length was 17.8 ± 11.8 cm. Lesions were categorized as occlusions in 43% (mean occluded length, 16 ± 10 cm). TASC type was A (17%), B (29%), C (38%), and D (15%). Technical success was 99%. Re-stenting was performed in 5% and thrombolysis in 0.6% of patients. Kaplan-Meier estimates for freedom from target lesion revascularization were 90%, 72%, and 62% at 12, 24, and 36 months. Freedom from target vessel revascularization was 88%, 68%, and 59% and freedom from major target limb amputation was 99.6%, 98.9%, and 98.9%, respectively, at 12, 24, and 36 months. Survival was 95%, 89%, and 85% at 12, 24, and 36 months.

CONCLUSIONS

This post-market registry-based study shows promising results in treating femoral-popliteal ISR with paclitaxel DCB in comparison to the results of plain balloon angioplasty reported in the literature. These results demonstrate the ability of the SVS VQI to conduct post-market evaluation of peripheral devices in partnership with industry and federal regulators.

Early Financial Outcomes of Physician Modified Endograft Programs are Dictated by Device Cost

INTRODUCTION

Physician-modified endografts (PMEGs) have been used for repair of thoracoabdominal aortic aneurysms (TAAAs) for 2 decades with good outcomes but limited financial data. This study compared the financial and clinical outcomes of PMEGs to the Cook Zenith-Fenestrated (ZFEN) graft and open surgical repair (OSR).

METHODS

A retrospective review of financial and clinical data was performed for all patients who underwent endovascular or OSR of juxtarenal aortic aneurysms and TAAAs from January 2018 to December 2022 at an academic medical center. Clinical presentation, demographics, operative details, and outcomes were reviewed. Financial data was obtained through the institution's finance department. The primary end point was contribution margin (CM).

RESULTS

Thirty patients met inclusion criteria, consisting of twelve PMEG, seven ZFEN, and eleven open repairs. PMEG repairs had a total CM of -$110,000 compared to $18,000 for ZFEN and $290,000 for OSR. Aortic and branch artery implants were major cost-drivers for endovascular procedures. Extent II TAAA repairs were the costliest PMEG procedure, with a total device cost of $59,000 per case. PMEG repairs had 30-d and 1-y mortality rates of 8.3% which was not significantly different from ZFEN (0.0%, P = 0.46; 0.0%, P = 0.46) or OSR (9.1%, P = 0.95; 18%, P = 0.51). Average intensive care unit and hospital stay after PMEG repairs were comparable to ZFEN and shorter than OSR.

CONCLUSIONS

Our study suggests that PMEG repairs yield a negative CM. To make these cases financially viable for hospital systems, device costs will need to be reduced or reimbursement rates increased by approximately $8800.

Locoregional Anesthesia's Association With Reduced Intensive Care Unit Stay After Elective Endovascular Aneurysm Repair: Impact of Temporal Changes in Practice Patterns

BACKGROUND

Elective endovascular aneurysm repair (EVAR) can be performed via local anesthetics and/or regional (epidural or spinal) anesthesia (locoregional [LR]), versus general anesthesia (GA), conferring reduced intensive care unit (ICU) and hospital stays. Current analyses fail to account for temporal changes in vascular practice. Therefore, this study aimed to confirm reductions in ICU and hospital stays among LR patients while accounting for changes in practice patterns.

MATERIALS AND METHODS

Using the Society for Vascular Surgery's Vascular Quality Initiative, elective EVARs from August 2003 to June 2021 were grouped into LR or GA. Outcomes included ICU admission and prolonged hospital stay (>2 d). Procedures were stratified into groups of 2 y periods, and outcomes were analyzed within each time period. Univariable and multivariate analyses were used to assess outcomes.

RESULTS

LR was associated with reduced ICU admissions (22.3% versus 32.1%, P < 0.001) and prolonged hospital stays (14.3% versus 7.9%, P < 0.001) overall. When stratified by year, LR maintained its association with reduced ICU admissions in 2014-2015 (21.8% versus 34.0%, P < 0.001), 2016-2017 (23.6% versus 31.6%, P < 0.001), 2018-2019 (18.5% versus 30.2%, P < 0.001), and 2020-2021 (15.8% versus 28.8%, P < 0.001), although this was highly facility dependent. LR was associated with fewer prolonged hospital stays in 2014-2015 (15.6% versus 20.4%, P = 0.001) and 2016-2017 (13.3% versus 16.6%, P = 0.006) but not after 2017.

CONCLUSIONS

GA and LR have similar rates of prolonged hospital stays after 2017, while LR anesthesia was associated with reduced rates of ICU admissions, although this is facility-dependent, providing a potential avenue for resource preservation in patients suitable for LR.

Preoperative Risk Factors Impacting Length of Stay After Transcarotid Artery Revascularization

BACKGROUND

Transcarotid artery revascularization (TCAR), using interoperative flow reversal is a unique, hybrid operation utilized in treating critical carotid artery stenosis. Over the past decade, TCAR has been increasingly used to treat asymptomatic carotid artery disease and has a similar risk profile to traditional carotid endarterectomy. Postoperative length of stay (LOS) has a significant impact on cost-effectiveness and quality outcomes in this expanded setting. The objective of this study is to develop a multivariate regression model to identify key preoperative variables and their impact factor on LOS after TCAR for asymptomatic carotid artery stenosis. We hypothesized that high-risk preoperative patient factors historically identified in carotid endarterectomy would similarly impact LOS after TCAR.

METHODS

A multi-institution, retrospective study of all adult patients undergoing TCAR with flow-reversal for intraoperative neuroprotection was performed using the Society for Vascular Surgery Vascular Quality Initiative (VQI) from January 2016 to August 2021. Patients with prolonged preoperative hospitalization (preoperative LOS ≥1 day) were excluded to enhance the capture of carotid artery stenosis as the index admission. Univariate analysis was done on preoperative factors against LOS using nonparametric statistical tests. A multivariate model was then constructed using a negative binomial regression. The study population was split into 80% "training" data for model formulation and 20% "test" data for model validation.

RESULTS

Thirteen thousand four hundred eighty-three patients undergoing TCAR for asymptomatic carotid stenosis met the study's inclusion criteria with a median postoperative LOS of 1.82 days. Factors in VQI found to have a significant effect on LOS and retained in the multivariate model were lesion type (restenosis versus atherosclerotic), age, gender, chronic obstructive pulmonary disease, preoperative beta blocker, calcific lesion burden, hypertension status, and race (P < 0.05). The model accurately predicted LOS after TCAR within 1 day for 86.04% and within 2 days for 94.51% of patients in the test population.

CONCLUSIONS

This large-scale analysis from 2016 to 2021 spans a considerable expansion in the practice of TCAR for asymptomatic carotid disease. All preoperative variables shown to significantly increase the postoperative LOS were derived from the VQI data set. As LOS is a measure of health-care efficiency and cost-effectiveness, this model can be used to identify patients at risk for increased postoperative LOS. It has the potential to be incorporated into a patient/physician decision support tool to optimize resource planning and patient selection for elective TCAR.

Survival, Reintervention, and Value of Open and Endovascular Repair for Chronic Mesenteric Ischemia

BACKGROUND

There are limited analyses of survival and postoperative outcomes in chronic mesenteric ischemia (CMI) using data from large cohorts. Current guidelines recommend open repair (OR) for younger, healthier patients when long-term benefits outweigh increased perioperative risks or for poor endovascular repair (ER) candidates. This study investigates whether long-term survival, reintervention, and value differ between these treatment modalities.

METHODS

A retrospective cohort analysis was performed on data extracted from the Statewide Planning and Research Cooperative System, the New York statewide all-payer database containing demographics, diagnoses, treatments, and charges. Patients were selected for CMI and subsequent ER or OR using International Classification of Diseases, Ninth Revision codes. Patients with peripheral arterial disease were excluded to account for ambiguity in the International Classification of Diseases, Ninth Revision procedure code for angioplasty of noncoronary vessels, which includes angioplasty of upper and lower extremity vessels. Kaplan-Meier analysis was used to compare 1-year and 5-year survival and reintervention between treatment modalities using a propensity-matched cohort. Cox proportional hazards testing was performed to find factors associated with 1-year and 5-year survival and reintervention. Analysis of procedural value was performed using linear regression.

RESULTS

From 2000 to 2014, 744 patients met inclusion criteria. Of these, 209 (28.1%) underwent OR and 535 (71.9%) ER. No difference between propensity-matched groups was found in 1-year (P = 0.46) or 5-year (P = 0.91) survival. Congestive heart failure (hazard ratio [HR]: 2.8, 95% confidence interval [CI]: 1.7-4.4; P < 0.01), cancer (HR: 2.8, 95% CI: 1.3-5.8; P < 0.01), and dysrhythmia (HR: 1.8, 95% CI: 1.1-2.8; P = 0.02) correlated with 1-year mortality. Cancer (HR: 2.9, 95% CI: 1.6-5.5; P < 0.01), congestive heart failure (HR: 2.2, 95% CI: 1.5-3.2; P < 0.01), chronic pulmonary disease (HR: 1.4, 95% CI: 1.0-2.0; P = 0.04), and age (HR: 1.03, 95% CI: 1.01-1.05; P < 0.01) correlated with 5-year mortality. Treatment modality was not associated with reintervention at 1 year on Kaplan-Meier analysis (P = 0.29). However, ER showed increased instances of reintervention at 5 years (P < 0.01). Additionally, ER was associated with an increased 5-year value (0.7 ± 0.9 vs. 0.5 ± 0.5 life years/charges at index admission [$10k], P < 0.01; b coefficient: 0.2, 95% CI: 0.1-0.4, P < 0.01).

CONCLUSIONS

This is the largest retrospective propensity-matched single-study cohort to analyze long-term survival outcomes after intervention for CMI. Long-term mortality was independent of treatment modality and rather was associated with patient comorbidities. Therefore, treatment selection should depend on anatomic considerations and long-term value. ER should be considered over OR in patients with amenable anatomy based on the superior procedural value.

Intermediate pressure-normalized principal wall strain values are associated with increased abdominal aortic aneurysmal growth rates

Introduction

Current abdominal aortic aneurysm (AAA) assessment relies on analysis of AAA diameter and growth rate. However, evidence demonstrates that AAA pathology varies among patients and morphometric analysis alone is insufficient to precisely predict individual rupture risk. Biomechanical parameters, such as pressure-normalized AAA principal wall strain (ε ρ + ¯ /PP, %/mmHg), can provide useful information for AAA assessment. Therefore, this study utilized a previously validated ultrasound elastography (USE) technique to correlate ε ρ + ¯ /PP with the current AAA assessment methods of maximal diameter and growth rate.

Methods

Our USE algorithm utilizes a finite element mesh, overlaid a 2D cross-sectional view of the user-defined AAA wall, at the location of maximum diameter, to track two-dimensional, frame-to-frame displacements over a full cardiac cycle, using a custom image registration algorithm to produce ε ρ + ¯ /PP. This metric was compared between patients with healthy aortas and AAAs (≥3 cm) and compared between small and large AAAs (≥5 cm). AAAs were then separated into terciles based on ε ρ + ¯ /PP values to further assess differences in our metric across maximal diameter and prospective growth rate. Non-parametric tests of hypotheses were used to assess statistical significance as appropriate.

Results

USE analysis was conducted on 129 patients, 16 healthy aortas and 113 AAAs, of which 86 were classified as small AAAs and 27 as large. Non-aneurysmal aortas showed higher ε ρ + ¯ /PP compared to AAAs (0.044 ± 0.015 vs. 0.034 ± 0.017%/mmHg, p = 0.01) indicating AAA walls to be stiffer. Small and large AAAs showed no difference in ε ρ + ¯ /PP. When divided into terciles based on ε ρ + ¯ /PP cutoffs of 0.0251 and 0.038%/mmHg, there was no difference in AAA diameter. There was a statistically significant difference in prospective growth rate between the intermediate tercile and the outer two terciles (1.46 ± 2.48 vs. 3.59 ± 3.83 vs. 1.78 ± 1.64 mm/yr, p = 0.014).

Discussion

There was no correlation between AAA diameter and ε ρ + ¯ /PP, indicating biomechanical markers of AAA pathology are likely independent of diameter. AAAs in the intermediate tercile of ε ρ + ¯ /PP values were found to have nearly double the growth rates than the highest or lowest tercile, indicating an intermediate range of ε ρ + ¯ /PP values for which patients are at risk for increased AAA expansion, likely necessitating more frequent imaging follow-up.

Impact of calcified plaque volume on technical and 3-year outcomes after transcarotid artery revascularization

OBJECTIVE

We sought to quantify the percent calcification within carotid artery plaques and assess its impact on percent residual stenosis and rate of restenosis in patients undergoing transcarotid artery revascularization for symptomatic and asymptomatic carotid artery stenosis.

METHODS

A retrospective review of prospectively collected institutional Vascular Quality Initiative data was performed to identify all patients undergoing transcarotid artery revascularization from December 2015 to June 2021 (n = 210). Patient and lesion characteristics were extracted. Using a semiautomated workflow, preoperative computed tomography head and neck angiograms were analyzed to determine the calcified plaque volume in distal common carotid artery and internal carotid artery plaques. Intraoperative digital subtraction angiograms were reviewed to calculate the percent residual stenosis post-intervention according to North American Symptomatic Carotid Endarterectomy Trial criteria. Peak systolic velocity and end-diastolic velocity were extracted from outpatient carotid duplex ultrasound examinations. Univariate logistic regression was performed to analyze the relationship of calcium volume percent and Vascular Quality Initiative lesion calcification to percent residual stenosis in completion angiograms. Kaplan-Meier analysis examined the relationship between calcium volume percent and in-stent stenosis over 36 months.

RESULTS

One hundred ninety-seven carotid arteries were preliminarily examined. Predilation was performed in 87.4% of cases with a mean balloon diameter of 5.1 ± 0.7 mm and a mean stent diameter was 8.8 ± 1.1 mm. The mean calcium volume percent was 11.9 ± 12.4% and the mean percent residual stenosis was 16.1 ± 15.6%. Univariate logistic regression demonstrated a statistically significant difference between calcium volume percent and percent residual stenosis (odds ratio [OR], 1.324; 95% confidence interval [CI], 1.005-1.746; P = .046). Stratified by quartile, only the top 25% of calcified plaques (>18.7% calcification) demonstrated a statistically significant association with higher percent residual stenosis (OR, 2.532; 95% CI, 1.049-6.115; P =.039). There was no statistical significance with lesion calcification (OR, 1.298; 95% C,: 0.980-1.718; P = .069). A Kaplan-Meier analysis demonstrated a statistically significant increase in the rate of in-stent stenosis during a 36-month follow-up for lesions containing >8.2% calcium volume (P = .0069).

CONCLUSIONS

A calcium volume percent of >18.7% was associated with a higher percent residual stenosis, and a calcium volume percent of >8.2% was associated with higher in-stent stenosis at 36 months. There was one clinically diagnosed stroke during the follow-up period, demonstrating the overall safety of the procedure.

Gore TAG thoracic branch endograft for treatment of a subacute type B aortic dissection complicated by rupture

An 80-year-old man presented with a subacute zone 3-5 type B aortic dissection complicated by rupture and visceral and lower extremity malperfusion. He underwent emergent zone 2 repair with a Gore TAG thoracic branch endograft with inclusion of the left subclavian artery for a dominant left vertebral artery. The patient's postoperative course was uncomplicated. Type B aortic dissections can be anatomically complex, and rupture is a rare complication in the subacute phase. We report the novel use of a Gore TAG thoracic branch endograft for the management of type B aortic dissection complicated by rupture and demonstrate its feasibility for patients with type B aortic dissection complicated by rupture.

Locoregional anesthesia is associated with reduced hospital stay and need for intensive care unit care of elective endovascular aneurysm repair patients in the Vascular Quality Initiative

OBJECTIVE

It has been shown local or regional anesthetic techniques are a feasible alternative to general anesthesia for endovascular aortic aneurysm repair (EVAR). However, studies to date have shown controversial findings with respect to the benefit of locoregional anesthesia (LR) in the elective setting. The objective of this study is to compare postoperative outcomes between LR and general anesthesia (GA) in the setting of elective EVAR, using a large, multicenter database.

METHODS

Using the Society for Vascular Surgery Vascular Quality Initiative database, we retrospectively analyzed all patients who underwent elective EVAR from August 2003 to June 2021. Patients were grouped by anesthetic type based on the level of consciousness afforded by the anesthetic: local or regional anesthesia (LR) vs GA. Primary outcomes were total postoperative hospital length-of-stay (LOS) and intensive care unit (ICU) LOS. Propensity score matching was used for risk adjustment and to analyze the primary outcomes with confirmatory analysis using logistic or linear regression, as appropriate, in single and multilevel models. Secondary outcomes were 30-day mortality, 1-year mortality, postoperative outcomes, operative time, fluoroscopy time, and reoperation rate. These were analyzed following propensity score matching as well as using logistic regression and Cox proportional hazard regression in single and multilevel models, as appropriate.

RESULTS

A total of 50,809 patients underwent elective EVAR from 2003 to 2021. Of these, 4302 repairs used LR (8.5%) and 46,507 (91.5%) were performed under GA. After employing propensity score matching, two groups of 3027 patients were produced. These showed no significant difference in 30-day mortality (odds ratio, 1.22; P = .53), 1-year mortality (hazard ratio, 1.06; P = .62), or any postoperative outcomes. LR was found to be significantly associated with shorter hospital stays (≤2 days) (12.5% vs 14.8%; P = .01), decreased ICU utilization (19.3% vs 30.6%; P < .001), decreased operative time (110.8 vs 117.3 minutes; P < .001), decreased fluoroscopy time (21.0 vs 22.7 minutes; P < .001), and a slight reduction in reoperation rate (1.2% vs 1.9%; P = .02), which all remained significant following single-level and multilevel multivariate analyses accounting for hospital and physician random effects.

CONCLUSIONS

These data suggest that LR anesthesia is safe and may offer advantages in reducing resource utilization for patients undergoing elective EVAR, primarily based on associations with reduced ICU care and reduced hospital stay. Given these findings, LR may prove an advantageous technique in appropriately selected patient populations.

Females are less likely to receive best medical therapy for stroke prevention before and after carotid revascularization than males

BACKGROUND

Current professional guidelines recommend best medical therapy (BMT) with statin agents and antiplatelet therapy for primary and secondary stroke prevention in patients with carotid artery stenosis. We aimed to assess the association of patient sex with preoperative BMT in patients undergoing carotid revascularization.

METHODS

We performed a retrospective review of Vascular Quality Initiative patients who underwent carotid endarterectomy or carotid artery stenting between January 2003 and February 2022. Multivariable logistic regression models were used to assess the association of patient sex with preoperative BMT after adjusting for sociodemographic, comorbidity, and disease severity characteristics. In-hospital outcomes were assessed by sex and preoperative BMT status.

RESULTS

Of 214,008 patients who underwent carotid revascularization, 38.7% (n = 82,855) were female and 61.3% (n = 131,153) were male. Overall, 77.2% (n = 63,922) of females were on preoperative BMT, compared with 80.4% (n = 105,375) of males (P < .001). After adjusting for baseline differences, females had 11% lower odds of being on BMT compared with males (adjusted odds ratio, 0.89; 95% confidence interval, 0.86-0.91). Postoperatively, females had 18% lower odds of being prescribed BMT than males (adjusted odds ratio, 0.82; 95% confidence interval, 0.79-0.84). In-hospital stroke (1.20% vs 1.51%), death (0.37% vs 0.66%), and stroke/death (1.46% vs 1.98%) were all significantly lower for patients on BMT (all P < .001).

CONCLUSIONS

There is a significant discrepancy in the proportion of females versus males receiving preoperative BMT for stroke prevention before carotid artery revascularization. In-hospital outcomes are worse in patients without BMT, highlighting the importance of raising awareness and implementing targeted interventions to improve preoperative adherence to stroke prevention guidelines.

Opioid sparing effects of the bupivacaine pleural catheter in surgical decompression of the thoracic outlet

OBJECTIVE

Rib resection in thoracic outlet decompression can result in significant postoperative pain requiring high levels of opioid medications. We evaluated the impact of a bupivacaine infusing pleural catheter on postoperative pain and opioid usage in patients undergoing rib resection for thoracic outlet syndrome. We hypothesized that delivery of local anesthetic via the pleural catheter would improve postoperative pain control compared to standard multimodal analgesia, and that the use of the catheter would decrease opioid use during the index hospitalization and prescriptions for opioid pain medications at discharge.

METHODS

We conducted a single-center retrospective cohort study of 26 patients who underwent rib resection for thoracic outlet decompression. Primary outcome was opioid consumption during the index hospitalization, measured in morphine milligram equivalents (MME). Secondary outcomes were MME prescribed at discharge and pain scores during the index hospitalization before and after the pleural drain and pleural catheter were removed.

RESULTS

Patients in the bupivacaine infusion pleural catheter group (n=11) had significantly lower milligram morphine equivalent (MME) usage during the index hospitalization (22.5 [1.9, 65.6] vs. 119.8 [76.5, 167.4]), and significantly lower MME prescribed at discharge (0 [0, 37.5] vs. 225 [183, 315]), compared to standard multimodal analgesia in controls (n=15). Only 3 patients in the bupivacaine pleural catheter group were discharged with any opioid prescriptions (27%), compared to 14 patients in the control group (93%). There was no difference in postoperative pain scores between groups before or after removal of the pleural drain, which was placed in all cases (p=0.31 and p=0.76, respectively).

CONCLUSIONS

Intraoperative placement of a bupivacaine infusion pleural catheter significantly reduced opioid use during the index hospitalization and opioid prescribing at discharge. Anesthetic infusion pleural catheters should be the treatment modality of choice for postoperative pain management in patients undergoing thoracic outlet decompression.

Left Subclavian Artery Coverage is Not Associated with Neurological Deficits in Trauma Patients Undergoing Thoracic Endovascular Repair

BACKGROUND

Endovascular repair of the thoracic aorta (TEVAR) outcomes have been studied with interest in complications related to left subclavian artery (LSA) coverage in patients with atherosclerotic pathologies; however, specific data on the management of the LSA in a trauma population is lacking. The objective of this study is to evaluate outcomes following TEVAR for traumatic aortic injury based on LSA coverage.

METHODS

The Vascular Quality Initiative thoracic endovascular aortic repair module (2010-2017) was analyzed. Patients were included if they had a traumatic aortic injury requiring TEVAR. Patients were placed in two groups based on coverage of the left subclavian artery. Patients were propensity score matched and the primary outcomes were cerebrovascular symptoms and spinal cord ischemia. Additional clinical and resource utilization outcomes were analyzed.

RESULTS

451 patients were included in the analysis. There were 268 patients in the LSA not covered group and 183 patients in the LSA covered group. The mean aortic injury grade was 2.88±0.056 vs 2.88±0.049 in the covered versus not-covered group (p=0.957). Glasgow coma scale and injury severity score were not different between the groups. There was no difference between groups for cerebrovascular symptoms or spinal cord ischemia, 1.4% vs 2.8% p=0.684 and 0% vs 2.1% p=0.247, after propensity score matching. Significant differences in access site complications and resource utilization were identified between groups.

CONCLUSION

This is the largest series to evaluate complications based on LSA coverage following TEVAR in trauma patients. Our data demonstrate that coverage of the LSA during TEVAR following blunt trauma is associated with no difference in CNS outcomes. As such, LSA revascularization strategies, while possible, are not directly supported by these data, and should be individualized based on each patient's specific clinical scenario.

A Reappraisal of CT Angiography Derived Duplex Ultrasound Velocity Criteria With a Comparison to Digital Subtraction Angiography in Patients With Carotid Artery Stenosis

BACKGROUND

Traditionally, carotid duplex ultrasound (CDUS) velocity criteria have been derived from angiography. Recent studies support a shift toward computed tomography angiography (CTA) derived velocity criteria; however, they lack a comparison to angiography. The purposes of this study are to validate CTA derived measurements with digital subtraction angiography (DSA) and to update our previous CTA-derived velocity criteria for 50% and 80% stenosis.

METHODS

All patients between 2010 and 2019 who underwent CDUS and a neck CTA within 6 months were identified for a retrospective review. Vessel diameter and corresponding CDUS data were recorded. Additional DSA measurements were recorded for a subset of patients. Data from this cohort were added to a previously reported deidentified data set from patients between 2000 and 2009. Receiver operating characteristic (ROC) curves were generated to determine optimal velocity thresholds. Spearman rank correlation was used to correlate measurements obtained by CTA to those obtained by DSA.

RESULTS

A total of 1139 vessels from 636 patients were analyzed. ROC analysis to identify ≥ 50% stenosis resulted in optimized thresholds of 143 cm/sec, 46.2 cm/sec, and 2.15 for peak systolic velocity (PSV), end-diastolic velocity (EDV), and PSV to common carotid artery PSV ratio (PSVR), respectively. ROC analysis to identify ≥ 80% stenosis resulted in optimized thresholds of 319 cm/sec, 87.2 cm/sec, and 3.49 for PSV, EDV, and PSVR, respectively. The degree of carotid artery stenosis for a subset of 124 vessels on CTA correlated well with that of DSA (ρ = 0.89, P< 0.0001).

CONCLUSIONS

These data demonstrate a high correlation between measurements obtained on CTA and DSA while forming reliable CTA-derived CDUS velocity criteria.

Evaluation of Opioid Prescription and Consumption Habits Following Endovascular Aortic Aneurysm Repair

BACKGROUND

There has been a dramatic rise in opioid-related deaths over the past decade. Most of the reduction strategies have focused on outpatient use; however, recent studies have demonstrated an association between inpatient opioid use and consumption following discharge across a variety of surgical procedures. The objective of this study is to evaluate the association of inpatient use of opioids as well as the consumption of opioids after discharge following endovascular aortic aneurysm repair (EVAR).

METHODS

A prospectively maintained database was reviewed for cases between 2015 and 2018. Patients were included in the study if they underwent an elective EVAR, had an intensive care unit stay less than 1 day and total length of stay less than 3 days. Patients were contacted to participate in a survey of opioid use if they received a prescription at discharge. The primary outcome was percent of prescribed opioids consumed following discharge. Multivariate analyses were performed to determine predictors of receiving an opioid prescription.

RESULTS

One hundred seventy-one patients were included in the analysis; 95% patients were white and 85% male. 59% of patients responded to the survey. Seventy-one (42%) received an opioid prescription at discharge. Patients that received a discharge prescription tended to be younger (71 vs. 75 years, P = 0.005) and more likely to have received opioids while in the hospital (79% vs. 45%, P < 0.001). Additionally, patients who received opioids at discharge received a significantly greater amount of milligram oral morphine equivalents (OME) while in the hospital (27.76 ± 38.91 vs. 10.05 ±29.43, P < 0.001). Multivariate analysis demonstrated age, estimated blood loss (EBL), and OME per day to be significant inpatient predictors of requiring an outpatient opioid prescription. Open femoral access (27%) was not a predictor of opioid prescription at discharge. A total of 1185 pills were prescribed (29.6 ± 2.06 per patient), but only 208 pills consumed (5.2 ± 1.27 per patient). Around 82% of total pills prescribed were not consumed.

CONCLUSIONS

This study evaluates inpatient opioid use and postdischarge consumption following EVAR. These data identify key factors associated with receiving an opioid prescription at discharge and demonstrate that patients consume far fewer opioids than prescribed. These findings provide insight as to which patients may not require an outpatient prescription following EVAR, leading to potential practice-changing opioid reduction strategies.

Postdischarge Opioid Use after Lower Extremity Bypass Surgery

BACKGROUND

Opioid overprescription for acute postoperative pain is an inadvertent contributor to the opioid epidemic via pill diversion and misuse. In response, the surgical community advocates for evidence-based postoperative opioid prescribing guidelines. The objective of this study is to evaluate patient-reported opioid consumption after lower extremity bypass surgery.

METHODS

We conducted a retrospective review of a prospectively maintained database of infrainguinal bypass operations from 2016 to 2019. For patients receiving an opioid prescription at discharge, a telephone survey was administered questioning the percentage of pills used. Exclusion criteria included chronic opioid use and reoperations or amputations within 30 days. The primary outcome was the difference in opioids prescribed versus opioids consumed.

RESULTS

Forty-nine patients met inclusion criteria. Forty-one (84%) were prescribed opioids at discharge, and 27 (65.9%) completed the survey. The average age was 65.8 ± 7.7 years; 29.6% were women. Oxycodone immediate-release was most commonly prescribed (78%). On average, patients received 318 ± 156 morphine milligram equivalent. A total of 940 opioid pills were prescribed (36.0 ± 11.3 per patient), but only 37% were consumed. This difference resulted in 568 unused pills.

CONCLUSIONS

This is the first study to specifically evaluate opioid use in a strictly lower extremity bypass population. Over 60% of pills were unused, which poses significant societal risk for misuse. Our findings contribute to knowledge of operation-specific opioid use, which may shape practice recommendations and reduce opioid overprescription after vascular surgery.

Totally percutaneous endovascular repair of HeartMate 3 ventricular assistive device outflow graft pseudoaneurysm

The rate of heart failure and subsequent placement of left ventricular assistive devices (LVADs) has been increasing. The extra-anatomic placement of the LVAD and outflow graft presents a challenging problem for repair when complications arise. The present report describes a case of a 63-year-old man who had presented with acute pseudoaneurysm of the outflow graft of his recently placed LVAD. Percutaneous access of the left subclavian artery and percutaneous, transthoracic access of the outflow graft was obtained to allow for sheath placement and stent deployment within the outflow graft. The patient underwent successful endovascular repair of the defect without complications.

Regional Variation in Usage of Ultrasound-Guided Femoral Access in the Vascular Quality Initiative

BACKGROUND

Access site complications are among the most common complications following peripheral vascular interventions. Previous studies have demonstrated a reduced rate of complications with ultrasound-guided vascular access (UGVA). The objective of this study is to evaluate the regional use of UGVA within the Vascular Quality Initiative (VQI).

METHODS

The VQI peripheral intervention module between 2010 and 2018 was evaluated. Regional ID was used to compare distribution of ultrasound usage. Regions were grouped into terciles based on the rate of ultrasound use. Patients were categorized based on type of access. Primary outcome was use of ultrasound across regions. Secondary outcomes were access site complications.

RESULTS

Over 43,000 cases across the 18 VQI regions were evaluated. The average rate of ultrasound usage was 71% across the regions with a wide variation (range 38-97%). There is a significant difference in utilization among the top third (87%), middle third (79%), and bottom third (58%) (P < 0.001). Average sheath size was similar across all 3 groups. A higher use of ultrasound-guided access was associated with significantly fewer access site complications (top third 1.96% vs. bottom third 3.04%, P < 0.001), the most significant of which was a decreased rate of access site hematoma (top third 1.37% vs. bottom third 2.35%, P < 0.001).

CONCLUSIONS

This is the first study to evaluate ultrasound-guided access across VQI regions. Our results demonstrate that despite strong evidence supporting the utilization of UGVA, there remains a wide variation in ultrasound usage across VQI regions. This is also the first study to show that the prevalence of ultrasound use in peripheral vascular interventions (PVI) is inversely related to access site complications. Given all of the data supporting the usage of UGVA across numerous specialties, our findings encourage the consideration of an ultrasound-first approach for vascular access in PVI and the implementation of targeted strategies and evidence-based guidelines to enhance UGVA utilization in PVI.

Early Outcomes in the ROADSTER 2 Study of Transcarotid Artery Revascularization in Patients With Significant Carotid Artery Disease

Background and Purpose:

Transcarotid artery revascularization (TCAR) is comprised of carotid artery stent placement with cerebral protection via proximal carotid artery clamping and reversal of cerebral arterial flow. The aim of the present study was to evaluate the safety and efficacy of TCAR performed by a broad group of physicians with variable TCAR experience.

Methods:

The ROADSTER 2 study is a prospective, open label, single arm, multicenter, postapproval registry for patients undergoing TCAR. Patients considered at high risk for complications from carotid endarterectomy with symptomatic stenosis ≥50% or asymptomatic stenosis ≥80% were included. The primary end point was procedural success, which encompassed technical success plus the absence of stroke, myocardial infarction, or death within the 30-day postoperative period. Secondary end points included technical success and individual/composite rates of stroke, death, and myocardial infarction (MI). All patients underwent independent neurological assessments before the procedure, within 24 hours, and at 30 days after TCAR. An independent clinical events committee adjudicated all major adverse events.

Results:

Between 2015 and 2019, 692 patients (Intent to Treat Population) were enrolled at 43 sites. Sixty cases had major protocol violations, leaving 632 patients adhering to the Food and Drug Administration-approved protocol (per-protocol population). The majority (81.2%) of operators were TCAR naïve before study initiation. Patients underwent TCAR for neurological symptoms in 26% of cases, and all patients had high-risk factors for carotid endarterectomy (anatomic-related 44%; physiological 32%; both 24%). Technical success occurred in 99.7% of all cases. The primary end point of procedural success rate in the Intent to Treat population was 96.5% (per-protocol 97.9%). The early postoperative outcomes in the Intent to Treat population included stroke in 13 patients (1.9%), death in 3 patients (0.4%), and MI in 6 patients (0.9%). The composite 30-day stroke/death rate was 2.3%, and stroke/death/MI rate was 3.2%. In the per-protocol population, there were strokes in 4 patients (0.6%), death in one patient (0.2%), and MI in 6 patients (0.9%) leading to a composite 30-day stroke/death rate of 0.8% and stroke/death/MI rate of 1.7%.

Conclusions:

TCAR results in excellent early outcomes with high technical success combined with low rates of postprocedure stroke and death. These results were achieved by a majority of operators new to this technology at the start of the trial. Adherence to the study protocol and peri-procedural antiplatelet therapy optimizes outcomes. Longer-term follow-up data are needed to confirm these early outcomes.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02536378.

Technical tips for success in transcarotid artery revascularization

Transcarotid artery revascularization is a minimally invasive technique performed by vascular surgeons for the management of carotid artery stenosis via direct access of the common carotid artery and stenting of the common and internal carotid artery atherosclerotic stenosis. Unlike the transfemoral approach for carotid artery stent angioplasty, the transcarotid artery revascularization procedure allows cerebral protection from embolization without manipulation of the internal carotid artery stenotic lesion via the ENROUTE Transcarotid Neuroprotection System (Silk Road Medical, Sunnyvale, CA). The ENROUTE reverse flow cerebral protection affords the opportunity to predilate carotid artery lesions with relative impunity before stent deployment. Our technique of transcarotid artery revascularization is detailed in this report of 70 patients (112 procedures) with <1% perioperative neurologic morbidity and documents clinical and hemodynamic (duplex ultrasound testing) success at more than 6 months' follow-up.

(PEAK) WALL STRESS AS AN INDICATOR OF ABDOMINAL AORTIC ANEURYSM SEVERITY

Abdominal aortic aneurysms, which consist of dilatations of the infra-renal aorta by at least 1.5 times of its normal diameter, are becoming a leading cause of death worldwide. Rupture often occurs unexpectedly, before a repair procedure is conducted. The AAA maximum diameter has been used as a clinical criterion to monitor AAA severity. However, assessment of AAA rupture risk requires knowledge of wall stress and wall strength at the potential rupture location. We conducted a study on 37 patient specific CT datasets to investigate the benefits of using peak wall stress instead of D_max for AAA rupture severity. Correlation between PWS and 24 geometric indices and biomechanical factors was studied where eleven of them showed a statistically significant correlation with PWS. A Finite Element Analysis Rupture Index was used to conclude that the use of D _max as a single predictor of AAA behavior and severity may be insufficient based on our patient population with a D_max smaller than the 5.5 cm, clinically recommended repair threshold.

Aortic Anatomic Severity Grade Correlates with Midterm Mortality in Patients Undergoing Abdominal Aortic Aneurysm Repair

BACKGROUND

Anatomic severity grade (ASG) can be used to assess abdominal aortic aneurysm (AAA) anatomic complexity. High ASG is associated with complications following endovascular repair of AAAs and we have demonstrated that ASG correlates with resource utilization. The hypothesis of this study is that ASG is directly related to midterm mortality in patients undergoing AAA repair.

METHODS

Patients who underwent infrarenal AAA repairs between July 2007 and August 2014 were retrospectively reviewed and ASG scores were calculated using 3-dimensional computed tomography reconstructions. Perioperative mortalities (≤30 days) were excluded. The ASG value of 15 was chosen based on previous receiver-operator curve analysis, which showed that an ASG of 15 was predictive of postoperative complications and resource utilization. The 5-year survivors and mortalities were compared utilizing comorbidities, pharmacologic variables, and anatomic variables at or above the defined threshold.

RESULTS

A total of 402 patients (80% male and 96% Caucasian) with complete anatomic and survival data were included in the analysis. Mean ASG and age at the time of repair were 16 ± 0.15 and 73 ± 0.43 years old, respectively. The 5-year mortality was significantly associated with ASG >15 (hazard ratio [HR]: 1.504, confidence interval [CI]: 1.077-2.100, P < .017), hyperlipidemia (HR: 1.987, CI: 1.341-2.946, P < .001), coronary artery disease (HR: 1.432, CI: 1.037-1.978, P < .029), and chronic obstructive pulmonary disease (HR: 1.412, CI: 1.027-1.943, P < .034). Kaplan-Meier analysis demonstrated improved survival in the low score ASG ≤15 group at 1, 3, and 5 years (96% vs 93%, 81% vs 69%, and 53% vs 41%; P = .0182; Figure 1).

CONCLUSIONS

Increasing aortic anatomic complexity as characterized by ASG >15 is an independent predictor of midterm mortality following elective infrarenal AAA repair. Therefore, it may be a useful tool for appropriate patient selection and risk stratification prior to elective infrarenal AAA repair.

Aortic endograft explantation in the setting of prior heterotopic renal allograft

It is rare to require explantation of an aortic endograft placed for endovascular aneurysm repair (EVAR). Sustained aneurysm growth in the setting of prior endovascular repair, despite secondary interventions and use of adjuncts, is the most common cause of EVAR explantation. An infected endograft and aneurysm rupture after EVAR represent more urgent or emergent indications for explantation and have a significantly greater associated morbidity and mortality. This case of endograft explantation is of even greater complexity, given the patient's specific history of aneurysm repair in the concomitant setting of a functioning renal allograft.

Aortoiliac calcification correlates with 5-year survival after abdominal aortic aneurysm repair

BACKGROUND

An anatomic severity grade (ASG) score to categorize and to define anatomic factors for abdominal aortic aneurysm (AAA) repair was proposed. Other studies have previously reported that aortic anatomic complexity is a marker of survival and resource utilization after repair, although it remains unclear whether individual components of the ASG score independently contribute to survival. This study analyzed and validated an aortic and iliac artery calcium scoring system that can potentially predict survival after AAA repair.

METHODS

Patients who underwent infrarenal AAA repairs from July 2007 to May 2012 were analyzed using complete 5-year records. Those who died ≤30 days of surgery were excluded. Calcium score (CS) was defined using the ASG scoring system for its basis by preoperative imaging <6 months before surgery. A CS for any patient was 0 to 5 points, the sum of the points assigned to aortic neck (2 points total) and iliac artery (3 points total) calcification. A receiver operating characteristic curve was used to determine a CS threshold for mortality. The 5-year survivors and deaths were compared in regard to comorbidities, pharmacology, and CS at or above the defined threshold. Each variable with a P value <.1 between the groups was then placed into a Cox proportional hazards model, with statistical significance of P < .05.

RESULTS

There were 356 patients who underwent AAA repair with complete 5-year follow-up data; 26% died within 5 years of surgery. Of these, 13% had CS of 0 with 15% mortality, 28% had CS of 1 with 21% mortality, 24% had CS of 2 with 24% mortality, 23% had CS of 3 with 35% mortality, 10% had CS of 4 with 40% mortality, and 2% had CS of 5 with 17% mortality. The receiver operating characteristic curve demonstrated an appropriate threshold of CS 3. Of these patients, 65% had a CS <3, whereas 35% had a CS ≥3. Patients with a CS ≥3 had a lower 5-year survival probability (P = .003). Comparing 5-year survivors and deaths in a Cox proportional hazards analysis, CS ≥3 was associated with a hazard ratio of 1.579 (95% confidence interval, 1.038-2.402; P = .0328).

CONCLUSIONS

A CS ≥3 is linked to a lower 5-year survival after AAA repair in our population. This system potentially can be another measure for risk stratification and serve as a means to predict midterm mortality in AAA repairs. Future study will be needed for further validation to predict midterm mortality and to better guide surgical decision-making.

Manufacturing Abdominal Aorta Hydrogel Tissue-Mimicking Phantoms for Ultrasound Elastography Validation

Ultrasound (US) elastography, or elasticity imaging, is an adjunct imaging technique that utilizes sequential US images of soft tissues to measure the tissue motion and infer or quantify the underlying biomechanical characteristics. For abdominal aortic aneurysms (AAA), biomechanical properties such as changes in the tissue's elastic modulus and estimates of the tissue stress may be essential for assessing the need for the surgical intervention. Abdominal aortic aneurysms US elastography could be a useful tool to monitor AAA progression and identify changes in biomechanical properties characteristic of high-risk patients. A preliminary goal in the development of an AAA US elastography technique is the validation of the method using a physically relevant model with known material properties. Here we present a process for the production of AAA tissue-mimicking phantoms with physically relevant geometries and spatially modulated material properties. These tissue phantoms aim to mimic the US properties, material modulus, and geometry of the abdominal aortic aneurysms. Tissue phantoms are made using a polyvinyl alcohol cryogel (PVA-c) and molded using 3D printed parts created using computer aided design (CAD) software. The modulus of the phantoms is controlled by altering the concentration of PVA-c and by changing the number of freeze-thaw cycles used to polymerize the cryogel. The AAA phantoms are connected to a hemodynamic pump, designed to deform the phantoms with the physiologic cyclic pressure and flows. Ultra sound image sequences of the deforming phantoms allowed for the spatial calculation of the pressure normalized strain and the identification of mechanical properties of the vessel wall. Representative results of the pressure normalized strain are presented.

Hypoxia and Ischemia Promote a Maladaptive Platelet Phenotype

Supplemental Digital Content is available in the text.

Objective—

Reduced blood flow and tissue oxygen tension conditions result from thrombotic and vascular diseases such as myocardial infarction, stroke, and peripheral vascular disease. It is largely assumed that while platelet activation is increased by an acute vascular event, chronic vascular inflammation, and ischemia, the platelet activation pathways and responses are not themselves changed by the disease process. We, therefore, sought to determine whether the platelet phenotype is altered by hypoxic and ischemic conditions.

Approach and Results—

In a cohort of patients with metabolic and peripheral artery disease, platelet activity was enhanced, and inhibition with oral antiplatelet agents was impaired compared with platelets from control subjects, suggesting a difference in platelet phenotype caused by the disease. Isolated murine and human platelets exposed to reduced oxygen (hypoxia chamber, 5% O₂) had increased expression of some proteins that augment platelet activation compared with platelets in normoxic conditions (21% O₂). Using a murine model of critical limb ischemia, platelet activity was increased even 2 weeks postsurgery compared with sham surgery mice. This effect was partly inhibited in platelet-specific ERK5 (extracellular regulated protein kinase 5) knockout mice.

Conclusions—

These findings suggest that ischemic disease changes the platelet phenotype and alters platelet agonist responses because of changes in the expression of signal transduction pathway proteins. Platelet phenotype and function should, therefore, be better characterized in ischemic and hypoxic diseases to understand the benefits and limitations of antiplatelet therapy.