Platelet function testing and clinical outcomes in peripheral arterial disease: Systematic review and narrative synthesis.

OBJECTIVE: This systematic review aims to comprehensively assess the contemporary literature on platelet function testing (PFT) in individuals undergoing revascularization therapy for peripheral arterial disease (PAD). The goal is to identify whether PFT can aid in detecting antiplatelet resistance, predicting post-procedural thrombotic complications, and informing tailored treatment strategies. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a literature review was conducted using PubMed databases. Search terms included relevant medical subject headings (MeSH) terms. Eligible articles published in English between 1990 and 2023 were analyzed. Studies that examined PFT outcomes in patients with PAD after lower extremity revascularization were included. RESULTS: Ten studies met the inclusion criteria. Various PFT methods were used, including thromboelastography with platelet mapping, multiplate analyzer, Cytochrome P450 2C19 testing, VerifyNow, corrected whole blood aggregometry, platelet function analyzer-100, and light transmission aggregometry. PFT identified individuals who were resistant or non-sensitive to antiplatelet therapy, with such patients facing increased risks of graft/stent thrombosis, amputation, and reintervention. However, substantial heterogeneity in surgical procedures, drug regimens, and testing methods was observed among the studies. CONCLUSIONS: PFTs can play a crucial role in detecting resistance and non-sensitivity to antiplatelet drugs in patients with PAD post-revascularization. However, heterogeneity of data and methods underlines the need for standardized protocols and consensus-building among PFTs. Enhancing clinical utility and reliability could help optimize antiplatelet thromboprophylaxis, minimize thrombotic complications, and improve treatment strategies in vascular surgery. Further research is necessary to solidify the role of PFTs in guiding antiplatelet therapy post-revascularization in patients with PAD.

Popliteal artery aneurysm ultrasound criteria for reporting characteristics.

INTRODUCTION: Duplex ultrasound (DUS) is the modality of choice for surveillance of popliteal artery aneurysms (PAAs). However, noninvasive vascular laboratories have no standard guidelines for reporting results. This study assessed reports of PAA DUS for inclusion of information pertinent to operative decision-making and timing of surveillance. METHODS: This study was a retrospective review of a multi-institutional repository that was queried for all patients with a PAA from 2008 to 2022 and confirmed via manual chart review. DUS reports were abstracted and images were individually annotated for features of interest including dimensions, flow abnormalities, and percent thrombus burden. RESULTS: A total of 166 PAAs in 130 patients had at least one DUS available for viewing. Postoperative surveillance of PAAs was performed at several intervals: the first at 30 months (IQR 3.7-113, n = 44), the second at 64 months (IQR 20-172, n = 31), and the third at 152 months (IQR 46-217, n = 16) after the operation. The largest diameter of operative PAAs (median 27.5 mm, IQR 21.8-38.0) was significantly greater than nonoperative PAAs (median 20.9 mm, IQR 16.7-27.3); p < 0.01. Fewer than 33 (21%) reports commented on patency of distal runoff. We calculated an average percent thrombus of 60% (IQR 19-81) in nonoperative PAAs, which is significantly smaller than 75% (IQR 58-89) in operative PAAs; p < 0.01. CONCLUSION: In this multi-institutional retrospective study, PAAs are often not followed at intervals recommended by the Society for Vascular Surgery guidelines and do not include all measurements necessary for clinical decision-making in the multi-institutional repository studied. There should be standardization of PAA DUS protocols performed by all noninvasive vascular laboratories to ensure completeness of PAA DUS images and inclusion of characteristics pertinent to clinical decision-making in radiology reports.

Complications of Carotid Interventions for Symptomatic Lesions after Systemic Thrombolysis.

BACKGROUND: Series detailing complications after carotid endarterectomy (CEA) and transfemoral carotid stenting (tfCAS) for patients presenting with neurologic symptoms that are treated with systemic thrombolysis (ST) are sparse. We sought to determine if treatment with ST was associated with a higher rate of post-carotid intervention complications. METHODS: A multispecialty, institutional, prospectively maintained database was queried for symptomatic patients treated with CEA or tfCAS from 2007 to 2019. The primary outcomes of interest were bleeding complications (access/wound complications, hematuria, intracranial hemorrhage) or need for reintervention, stroke, and death. We compared rates of these outcomes between patients who were and were not treated with ST. To adjust for preoperative patient factors and confounding variables, propensity scores for assignment to ST and non-ST were calculated. RESULTS: There were 1,139 patients included (949 [82%] CEA and 190 [17%] tfCAS. All treated lesions were symptomatic (550 [48%] stroke, 603 [52%] transient ischemic attack). Fifty-six patients (5%) were treated with ST. Fifteen of 56 patients also underwent catheter-based intervention for stroke. ST was administered 0 to 1 day preoperatively in 21 (38%) patients, 2 to 6 days preoperatively in 27 (48%) patients, and greater than 6 days preoperatively in 8 (14%) patients. ST patients were more likely to present with stroke (93% vs. 45%; P < 0.001) and have higher preoperative Rankin scores. Unadjusted rate of bleeding/return to operating room was 3% for ST group and 3% for non-ST group (P = 0.60). Unadjusted rate of stroke was 4% for ST group and 3% for the non-ST group (P = 0.91), while perioperative mortality was 5% for ST group and 1% for non-ST group (P = 0.009). After adjusting for patient factors, preoperative antiplatelet/anticoagulation, and operative factors, ST was not associated with an increased odds of perioperative bleeding/return to the operating room (odds ratio 0.37; 95% confidence interval: 0.02-1.63; P = 0.309) or stroke (odds ratio 0.62; 95% confidence interval: 0.16-2.40; P = 0.493). CONCLUSIONS: ST does not convey a higher risk of complications after CEA or tfCAS. After controlling for other factors, patients that received ST had similar rates of local complications and stroke when compared to non-ST patients. Early carotid intervention is safe in patients that have received ST, and delays should be avoided in symptomatic patients given the high risk of recurrent stroke.

Local Anesthesia for Endovascular Repair of Abdominal Aortic Aneurysm Allows for Accurate Graft Deployment with Durable Results.

BACKGROUND: Local anesthesia (LA) is sparsely used in endovascular aneurysm repair (EVAR) despite short-term benefit, likely secondary to concerns over patient movement preventing accurate endograft deployment. The objective of this study is to examine the association between anesthesia type and endoleak, sac regression, reintervention, and mortality. METHODS: The Vascular Quality Initiative database was queried for all EVAR cases from 2014 to 2022. Patients were included if they underwent percutaneous elective EVAR with anatomical criteria within instructions for use of commercially approved endografts. Multivariable logistic regression with propensity score weighting was used to determine the association between anesthesia type on the risk of any endoleak noted by intraoperative completion angiogram and sac regression. Multivariable survival analysis with propensity score weighting was used to determine the association between anesthesia type and endoleak at 1 year, long-term reintervention, and mortality. RESULTS: Thirteen thousand nine hundred thirty two EVARs met inclusion criteria: 1,075 (8%) LA and 12,857 (92%) general anesthesia (GA). On completion angiogram, LA was associated with fewer rates of any endoleaks overall (16% vs. 24%, P < 0.001). On multivariable analysis with propensity score weighting, LA was associated with similar adjusted odds of any endoleak on intraoperative completion angiogram (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.47-0.68) as well as combined type 1a and type 1b endoleaks (OR 0.72, 95% CI 0.47-1.09). Follow-up computed tomography imaging at 1 year was available for 4,892 patients, 377 (8%) LA and 4,515 (92%) GA. At 1 year, LA was associated with similar rate of freedom from any endoleaks compared to GA (0.66 [95% CI 0.63-0.69] vs. 0.71 [95% CI 0.70-0.72], P = 0.663) and increased rates of sac regression (50% vs. 45%, P = 0.040). On multivariable analysis with propensity score weighting, LA and GA were associated with similar adjusted odds of sac regression (OR 1.22, 95% CI 0.97-1.55). LA and GA had similar rates of endoleak at 1 year (hazard ratio [HR] 0.14, 95% CI 0.63-1.07); however, LA was associated with decreased hazards of combined type 1a and 1b endoleaks at 1 year (HR 0.87, 95% CI 0.80-0.96). LA and GA had similar adjusted long-term reintervention rate (HR 0.77, 95% CI 0.44-1.38) and long-term mortality (HR 1.100, 95% CI 079-1.25). CONCLUSIONS: LA is not associated with increased adjusted rates of any endoleak on completion angiogram or at 1-year follow-up compared to GA. LA is associated with decreased adjusted rates of type 1a and type 1b endoleak at 1 year, but similar rates of sac regression, long-term reintervention, and mortality. Concerns for accurate graft deployment should not preclude use of LA and LA should be increasingly considered when deciding on anesthetic type for standard elective EVAR.

Optimizing platelet inhibition in peripheral artery disease: A comparison of mono-antiplatelet therapy and dual-antiplatelet therapy using thromboelastography.

BACKGROUND: Antiplatelet therapy is used to prevent thrombosis in patients with peripheral artery disease (PAD) following revascularization. However, the current standard of care for these patients remains at the physician's discretion, varying from mono-antiplatelet therapy (MAPT) to dual-antiplatelet therapy (DAPT). Viscoelastic assays such as Thromboelastography with Platelet Mapping (TEG-PM) provide insight into individual coagulation profiles and measure real-time platelet function. This prospective, observational study looks at the differences in platelet function for patients on MAPT versus DAPT using TEG-PM. METHODS: Patients with PAD undergoing revascularization were prospectively evaluated between December 2020 and June 2023. TEG-PM analysis compared platelet function for patients prescribed MAPT (aspirin or clopidogrel) at the initial encounter and DAPT (aspirin and clopidogrel) at the next visit. Platelet function measured in percent inhibition was evaluated at these visits, and within-group t-tests were performed. RESULTS: Of the 195 patients enrolled, 486 samples were analyzed by TEG-PM. Sixty-four patients met the study criteria. At the initial visit, 52 patients had been prescribed aspirin, and 12 patients had been prescribed clopidogrel. For patients initially prescribed aspirin MAPT, an increase of 96.8%in the mean ADP platelet inhibition was exhibited when transitioning to DAPT [22.0% vs. 43.3%, p < .01], as well as an increase of 34.6%in the mean AA platelet inhibition when transitioning to DAPT [60.9% vs. 82.0%, p < .01]. For patients prescribed initial clopidogrel MAPT, an increase of 100% in AA platelet inhibition was exhibited on DAPT compared to the MAPT state [42.3% vs. 84.6%, p < .01]. CONCLUSIONS: Patients on DAPT showed a significant increase in platelet inhibition when compared to initial aspirin MAPT. A significant difference in AA %platelet inhibition was shown for patients on DAPT when compared to initial clopidogrel MAPT. The results show that patients may benefit from DAPT post-revascularization. Personalizing antiplatelet therapy with objective viscoelastic testing to confirm adequate treatment may be the next step in optimizing patient outcomes to reduce thrombosis in PAD patients.

Reassuring Intraoperative Parameters Do Not Obviate the Need for Infrainguinal Bypass Completion Angiograms.

OBJECTIVE: To determine if routine completion angiography for lower extremity bypasses using vein conduit results in lower rates of postoperative bypass occlusion. SUMMARY OF BACKGROUND DATA: With the increasing availability of on-table angiography and significant advancements in endovascular techniques, some operators routinely perform completion angiograms. The effect of this surgical paradigm has yet to be rigorously compared to the more widespread selective use of completion imaging in the modern era. METHODS: This retrospective cohort study included infrainguinal arterial bypass procedures utilizing vein conduit completed at a single hospital system from 2001 to 2018 and compared postoperative outcomes between bypasses that underwent routine completion angiography versus selective completion angiography. Notably, any bypasses that underwent completion angiography due to intraoperative concerns were excluded from this analysis. RESULTS: 666 bypasses that were performed in 589 patients met inclusion criteria. 126 (16.9%) bypasses were classified into the routine completion angiogram group compared to 540 (81.0%) into the selective completion angiogram group. Patients who underwent routine completion angiograms had a rate of intraoperative reintervention of 22.2%. The routine angiogram group had lower rates of reintervention (3.9% vs 10.0%, P = 0.03) and graft occlusion (2.3% vs 9.2%, P = 0.01) at 1-month postoperatively. CONCLUSION: Lower extremity bypasses using vein conduit that undergo routine completion angiography are associated with lower rates of graft occlusion at 30-days postoperatively. Completion angiography should thus be routinely performed in infrainguinal bypasses that utilize venous conduit.

Effect of after-hours presentation in ruptured abdominal aortic aneurysm.

OBJECTIVE: Ruptured abdominal aortic aneurysms (RAAAs) are surgical emergencies that require immediate and expert treatment. It has been unclear whether presentation during evenings and weekends, when "on call" teams are primarily responsible for patient care, is associated with worse outcomes. Our objective was to evaluate the outcomes of patients presenting with RAAAs after-hours vs during the workday. METHODS: A retrospective cohort study of all RAAAs in Nova Scotia between 2005 and 2015 was performed through linkage of administrative databases. Patients who had presented to the hospital with RAAAs during the workday (Monday through Friday, 6 am to 6 pm) were compared with those who had presented after-hours (6 pm to 6 am during the week and on weekends). The baseline and operative characteristics were identified for all patients through the available databases and a review of the medical records. Mortality before surgery, 30-day mortality, and operative mortality were compared between groups using multivariable logistic regression, adjusting for factors clinically significant on univariable analysis. RESULTS: A total of 390 patients with RAAAs were identified from 2005 to 2015, of whom 205 (53%) had presented during the workday and 185 (47%) after-hours. The overall chance of survival (OCS) was 45% overall, 49% if admitted to hospital, and 64% if surgery had been performed. During the workday, the OCS was 43% overall, 48% if admitted to hospital, and 67% if surgery had been performed. After-hours, the OCS was 46% overall, 49% if admitted to hospital, and 61% if surgery had been performed. Mortality before surgery was increased for patients who had presented to the hospital during the workday compared with after-hours (36% vs 26%; P = .04). The 30-day mortality (57% vs 54%; P = .62), rates of operative management (63% vs 72%; P = .06), and operative mortality (33% vs 39%; P = .33) were similar between the workday and after-hours groups (57% vs 54%; P = .06). After adjusting for significant clinical variables, the patients who had presented with RAAAs after-hours had had a similar odds of dying before surgery (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.41-1.03), operative management (OR, 1.47; 95% CI, 0.93-2.31), 30-day mortality (OR, 0.98; 95% CI, 0.63-1.51), and operative mortality (OR, 1.33; 95% CI, 0.78-2.26). In the subgroup of patients presenting to a hospital with endovascular capabilities, patients presenting after-hours had had similar odds of 30-day mortality (OR, 1.07; 95% CI, 0.57-2.02), and operative mortality (OR, 1.14; 95% CI, 0.58-2.23). CONCLUSIONS: We found that patients presenting to the hospital with RAAAs after-hours did not have increased adjusted odds of mortality before surgery, operative management, 30-day mortality, or operative mortality.

Impact of Factor Xa Inhibition on Coagulation, Platelet Reactivity, and Thrombosis in Patients with Peripheral Artery Disease.

BACKGROUND: The role of thrombin in vascular pathology is a focus of investigation. The incorporation of direct Factor Xa inhibition into practice patterns is based on its theoretical dual-pathway attenuation of both thrombin generation and platelet aggregation. However, quantification of the effect of direct anti-Xa medications on platelet function is not established. Thromboelastography with platelet mapping (TEG-PM) leverages dual-pathway metrics to provide comprehensive coagulation profiles. We evaluated the effects of direct oral anticoagulants (DOACs) on coagulation and platelet function profiles and correlate these data with postoperative major adverse limb events (MALEs) in patients with PAD. METHODS: We conducted a prospective study of patients undergoing lower extremity revascularization with serial perioperative TEG-PM analysis. Patients on DOACs were compared to those not on DOACs, and stratified by concurrent mono-antiplatelet or dual-antiplatelet regimens (MAPT/DAPT). Postoperative MALE was recorded and difference in antithrombotic regimens and TEG-PM analysis compared between groups. RESULTS: Four hundred seventy-one samples from 141 patients were analyzed. Twenty-nine point five percent were reflective of circulating DOAC therapy. Compared to MAPT alone, patients on DOAC + MAPT exhibited longer time to clot formation (R-time) [7.4 (±2.4) vs. 6.7 (±2.7); P < 0.02], but less platelet inhibition. Patients on DAPT exhibited greater platelet inhibition compared to either group [23.7 (±26.9) vs. 31.0 (±28.3) vs. 42.2 (±31.2); P < 0.01]. Patients who experienced MALE were more likely to be on DOAC therapy [43.8% vs. 22.0% P = 0.02]. Thromboelastography with platelet mapping analysis from patients who experienced MALE also demonstrated longer R-time [8.6 (±3.9 vs. 7.3 (±3.0); P = 0.05] and increased maximum clot amplitude (MA) [66.7 (±4.2) vs. 61.8 (±8.2); P = 0.001]. CONCLUSIONS: Direct oral anticoagulant therapy resulted in a prolonged R-time but had no impact on platelet inhibition. Patients who experienced MALE were more often on DOACs and demonstrated an increased R-time, but also showed greater platelet reactivity evident by increased MA, suggesting DOACs may not be effective at protecting against MALE. Further research comparing DOAC therapy to a DAPT approach may add clarity to emerging multimodal antithrombotic recommendations.

Trends in Incidence of Abdominal Aortic Aneurysm Rupture, Repair, and Mortality in Nova Scotia.

BACKGROUND: The purpose of this study was to examine sex-based trends in incidence of elective abdominal aortic aneurysm (AAA), ruptured AAA, ruptured AAA repair, and AAA-related mortality. METHODS: A retrospective analysis of patients presenting with AAA from 2005 to 2015 was conducted. Rates of elective AAA repair, ruptured AAA, ruptured AAA repair, and mortality were obtained from linking provincial administrative data using medical services insurance billing number. The age-adjusted incidence of elective AAA repair, overall rate of ruptured AAA, ruptured AAA repair, and AAA-related mortality was calculated for each sex based on Canadian census estimates, adjusted to the Canadian standard population. Weighted linear regression was performed to analyze trends in incidence over time. RESULTS: One thousand nine hundred eighty-six elective AAA repairs were identified, of which 1,098 were repaired open and 898 underwent endovascular abdominal aneurysm repair (EVAR). Five hundred and seventy ruptured AAAs were identified, of which 295 (52%) were repaired: 259 open and 36 EVAR. The proportion of ruptured AAA that was repaired did not change over time (P = 0.54). The proportion repairs performed using EVAR increased significantly in both elective (P < 0.001) and rupture repairs (P < 0.001). During the study period, 662 patients died of AAA-associated mortality. The average incidence of elective AAA repair in men was 29.3 (95% confidence interval (CI): 27.8 to 30.8) per 100,000 and decreased over time (P = 0.04), whereas the average incidence in women was 9.2 [8.3 to 10.0] and stable (P = 0.07). The incidence of open elective AAA repair was 10.5 [9.9-11.1] with a decreasing trend over time (P < 0.001) and EVAR was 9.0 (8.5-9.6) with an increasing trend over time (P < 0.001). A decreasing trend of overall ruptured AAA (5.4 [5.0-5.9], P < 0.001), ruptured AAA repair (2.9 [2.5-3.2], P = 0.02), and of AAA-related mortality (6.2 [5.8-6.8], P < 0.001) was found, with consistent trends in both sexes. The incidence of open ruptured AAA repair decreased over time (P = 0.001) whereas the incidence of ruptured EVAR remained stable (P = 0.23). CONCLUSIONS: The incidence of elective AAA repair is decreasing in males but not females, whereas the incidence of rupture has decreased in both sexes. This has translated into reduced incidence of AAA-related mortality. Increased adoption of EVAR for ruptured AAA should continue these trends.

Dying to Get There: Patients Who Reside at Increased Distance from Tertiary Center Experience Increased Mortality Following Abdominal Aortic Aneurysm Rupture.

BACKGROUND: Centralization of vascular surgery care for Ruptured Abdominal Aortic Aneurysms (RAAAs) to high-volume tertiary centers may hinder access to timely surgical intervention for patients in remote areas. The objective of this study was to determine the association between distance from vascular care and mortality from RAAAs in the province of Nova Scotia, Canada. METHODS: A retrospective cohort study of all RAAAs in Nova Scotia between 2005 and 2015 was performed through linkage of administrative databases. Patients were divided into groups by estimated travel time from their place of residence to the tertiary center (<1 hr and ≥1 hr) using geographic information software. Baseline and operative characteristics were identified for all patients through available databases and completed through chart review. Mortality at home, during transfer to the vascular center, and overall 30-day mortality were compared between groups using t-test and chi-squared test, as appropriate. Multivariable logistic regression analysis was used to calculate the independent effect of travel time on survival outcomes. RESULTS: A total of 567 patients with RAAA were identified from 2005-2015, of which 250 (44%) resided <1 hr travel time to the tertiary center and 317 (56%) resided ≥1 hr. On multivariable analysis, travel time ≥1 hr from vascular care was an independent predictor of mortality at home (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.07-2.63, P = 0.02), mortality prior to operation (OR 2.64, 95% CI 1.81-3.83, P < 0.001), and overall 30-day mortality (OR 1.61, 95% CI 1.10-2.37, P = 0.02). In patients who received an operation (n = 294), there was no association between increased travel time and mortality (OR 1.02, 95% CI 0.60-1.73, P = 0.94). CONCLUSIONS: Travel time ≥1 hr to the tertiary center is associated with significantly higher mortality from ruptured abdominal aortic aneurysm (AAA). However, there was no difference in overall chance of survival between groups for patients that underwent AAA repair. Therefore, strategies to facilitate early detection, and timely transfer to a vascular surgery center may improve outcomes for patients with RAAA.

Atorvastatin Effect on Clopidogrel Efficacy in Patients with Peripheral Artery Disease.

BACKGROUND: Both clopidogrel and atorvastatin metabolism are rooted in hepatic cytochrome p450 activation. There are published reports of atorvastatin interfering with clopidogrel metabolism by inhibiting the activation of clopidogrel. This in turn would decrease the therapeutic effect of clopidogrel potentially resulting in an increase in thrombotic events in patients who are taking both medications. The emergence of viscoelastic assays, such as Thromboelastography with platelet mapping (TEG-PM), has been utilized to identify prothrombotic states and may provide insight into a patient's microvascular coagulation profile. The aim of this prospective, observational study was to delineate the differences in platelet function between patients on clopidogrel alone versus those on clopidogrel and atorvastatin in patients that are undergoing peripheral revascularization. METHODS: All patients undergoing revascularization between December 2020 and August 2022 were prospectively evaluated. Patients on clopidogrel and atorvastatin were compared to those on clopidogrel alone. Serial perioperative TEG-PM analysis was performed up to 6 months postoperatively and the platelet function in terms of percent inhibition was evaluated in both groups. Statistical analysis was performed using unpaired t-test to identify differences in platelet function. RESULTS: Over the study period, a total of 182 patients were enrolled. Of this cohort 72 patients met study criteria. 87 samples from the 72 patients were analyzed. 31 (43.05%) patients were on clopidogrel alone and 41 (56.94%) were on clopidogrel and atorvastatin. Patients on clopidogrel alone showed significantly greater platelet inhibition compared to those on clopidogrel and atorvastatin [49.01% vs. 34.54%, P = 0.03]. There was no statistical difference in platelet inhibition between groups in terms of aspirin use alone versus aspirin and atorvastatin. CONCLUSIONS: Patients on clopidogrel and atorvastatin showed significantly less platelet inhibition compared to those on clopidogrel alone, supporting the concept that atorvastatin may interfere with the therapeutic effect of clopidogrel. Patients taking atorvastatin may require an alternative antiplatelet therapy regimen that does not include clopidogrel to achieve adequate thromboprophylaxis.

Effect of socioeconomic status on patients undergoing elective abdominal aortic aneurysm repair in a publicly funded health care system.

BACKGROUND: The association between socioeconomic status (SES) and outcomes after abdominal aortic aneurysm (AAA) repair in publicly funded health care systems is poorly described. The purpose of this study was to determine the effect of SES on postoperative outcomes in patients who underwent AAA repair in Nova Scotia, Canada. METHODS: We performed a retrospective analysis of all elective AAA repairs in Nova Scotia between November 2005 and March 2015 using administrative data sources. We compared postoperative 30-day outcomes and long-term survival across socio-economic quintiles, defined as the Pampalon Material Deprivation Index (MDI) and Social Deprivation Index (SDI). We also compared the relation between baseline characteristics, MDI quintile, SDI quintile and 30-day mortality. We used multivariable logistic regression and survival analysis to calculate adjusted 30-day mortality and long-term survival, respectively. RESULTS: A total of 1913 patients underwent AAA repair during the study period. The overall 30-day mortality rate was 2.6% (50 patients). Thirty-day outcomes including death (p = 0.8), stroke (p = 0.7), myocardial infarction (p = 0.06), length of stay (p = 0.3) and discharge disposition other than home (p = 0.8) were similar across MDI quintiles. Similarly, there was no statistically significant association between SDI quintile and postoperative outcomes. Multivariable analysis showed that age greater than 70 years (odds ratio [OR] 3.06, 95% confidence interval [CI] 1.55-6.06) and open repair (OR 3.22, 95% CI 1.59-6.52) but not MDI quintile (p = NS) or SDI quintile (p = NS) were associated with increased 30-day mortality. There was no effect of MDI or SDI quintile on long-term survival on univariable or multivariable analysis. CONCLUSION: Socioeconomic status does not appear to affect short- or long-term mortality after AAA repair in a publicly funded health care system. Further research is needed to address any existing gaps in screening and referral before repair.

Risk factors and consequences of graft infection after femoropopliteal bypass: A 25-year experience.

OBJECTIVE: In this multi-institutional series, we aimed to determine the incidence, risk factors, and long-term outcomes of graft infection in patients post-femoropopliteal bypass. METHODS: A multi-institutional database was retrospectively queried for all femoropopliteal bypass procedures from 1995 through 2020. Cumulative incidence function estimated the long-term rate of bypass graft infection (BGI), and the Fine-Gray model was used to determine independent risk factors for BGI to account for death as a competing risk. RESULTS: Over the 25-year period, 1315 femoral popliteal bypasses were identified with a median follow-up of 2.89 years (interquartile range, 0.75-6.55 years). BGI was diagnosed in 34 patients (2.6%). BGI occurred between 9 days and 11.2 years postoperatively, with a median of 109 days. Estimated 1- and 5-year incidence of BGI was 2.1% (95% confidence interval [CI], 1.4%-3.1%) and 2.8% (95% CI, 1.9%-3.9%), respectively. Medical comorbidities, indications for bypass, and popliteal bypass targets (above- vs below-knee) were similar between patients with BGI and all patients (P = not significant for each). Patients with BGI were more frequently complicated by postoperative hematoma (14.7% vs 3.7%), superficial wound infection (38.2% vs 19.2%), lymphocele/lymphorrhea (8.8% vs 2.1%), and 30-day readmission rates (47.1% vs 21.3%) (P < .05 for each). Most commonly isolated pathogens were Staphylococcus aureus (n = 19; 55.9%) and polymicrobial cultures (n = 5; 14.7%). Reoperation for BGI involved incision and drainage (n = 7; 20.6%), graft excision without reconstruction (n = 12; 35.3%), graft excision with in-line reconstruction (n = 11; 32.4%), and graft excision with extra-anatomic reconstruction (n = 2; 5.9%). Nine patients with BGI (26.5%) ultimately required major amputation. Prosthetic bypass (subdistribution hazard ratio [SHR], 3.73; 95% CI, 1.64-8.51; P = .002), postoperative hematoma (SHR, 3.44; 95% CI, 1.23-9.61; P = .018), and 30-day readmission (SHR, 2.75; 95% CI, 1.27-5.44; P = .010) were independently associated with BGI. One-year amputation-free survival was 50% (95% CI, 31.9%-65.7%) after BGI. CONCLUSIONS: BGI is a rare complication of femoral-popliteal bypass with significant morbidity. Graft infection is associated with the use of prosthetic grafts, postoperative hematoma, and unplanned hospital readmission. Mitigation of these risk factors may decrease the risk of this dreaded complication.

Impact of anticoagulation/antiplatelet therapy on femoropopliteal bypass graft outcomes.

BACKGROUND: Anticoagulant and antiplatelet (AC/AP) medications have been reported to improve bypass graft patency, however, the optimal AC/AP strategy remains unclear in the heterogenous peripheral artery disease population. METHODS: A multi-institutional retrospective review utilizing the Research Patient Data Registry database from 1995 to 2020 was performed for all patients who underwent femoropopliteal bypass procedures. Electronic medical records were used to obtain demographic information, comorbidities, smoking status, operative details (bypass target), postoperative AC/AP medications, postoperative complications, and long-term outcomes and were reviewed for the cohort. Cox proportional hazards model was used to determine independent risk factors for major adverse limb events (MALE) after bypass. MALE was defined as reintervention for patency or major amputation of index limb (above- or below-knee amputation). RESULTS: A total of 1421 patients underwent femoropopliteal bypass between 1995 and 2020 throughout five institutions included in this study. Complete data were available for 1292 of the 1421 patients (90.9%). The indications for bypass included intermittent claudication (21.4%), rest pain (30.3%), tissue loss (33.5%), and nonatherosclerotic disease (14.8%). Distal bypass targets comprised above-knee (38.6%) and below-knee (61.4%) popliteal arteries. Patients were divided into six groups based on postoperative AC/AP use including none (n = 57 [4.4%]), monoantiplatelet therapy (n = 587 [45.4%]), dual AP therapy (n = 214 [16.6%]), AC alone (n = 73 [5.7%]), AC + monoantiplatelet therapy (n = 319 [24.7%]), and AC + dual AP therapy (n = 42 [3.3%]). Postoperative bleeding complications were low for both hematoma (3.7%) and pseudoaneurysm (0.7%). There was no difference in bleeding complications across AC/AP groups (hematoma, P = .61; pseudoaneurysm, P = .31). After adjusting for patient factors, below-knee bypass target (hazard ratio [HR], 1.25; 95% confidence interval [CI], 1.04-1.52; P = .019) and bypass for tissue loss (HR, 1.40; 95% CI, 1.04-1.88; P = .028) were independent predictors for MALE. Great saphenous vein conduit trended toward protection for MALE, compared with prosthetic grafts (HR, 0.84; 95% CI, 0.70-1.01; P = .06). No AC/AP regimen was associated with of MALE, even stratifying by above-knee and below-knee bypass cohorts. The median follow-up period was 2 years. CONCLUSIONS: Among patients undergoing femoropopliteal bypass grafting, no combination of AC or AP medications was associated with improved graft patency; however, a below-knee target and tissue loss were associated with adverse limb events. AC and AP regimen may be individualized after bypass with regard to other concomitant medical comorbidities.

Outcomes of Femoropopliteal Bypass for Lifestyle-Limiting Claudication in the Endovascular Era.

INTRODUCTION: Outcomes after femoropopliteal bypass for intermittent claudication (IC) remain unclear in the endovascular era. METHODS: A multi-institutional database was retrospectively queried for all femoropopliteal bypass procedures performed between 1995 and 2020. Demographics, operative details, and outcomes were documented. A statistical analysis included Kaplan-Meier curves and Cox proportional hazards ratios (HR). RESULTS: A total of 282 patients underwent femoropopliteal bypass surgery for IC. Median age was 68 y (interquartile range, 61-73 y). Bypass conduits included great saphenous vein (GSV) (48.2%), prosthetic grafts (48.9%), and non-GSV autogenous grafts (2.8%). Distal bypass target was above-knee in 62.1% and below-knee in 37.9% of patients. The most common postoperative complications were wound infections (14.2%) followed by unplanned 30-d hospital readmissions (12.4%). Mortality rates were low at 0.4% (30 d) and 3.2% (1 y). Five-year primary patency rates trended highest for claudicants undergoing above-knee bypass with GSV conduit (log-rank P = 0.065). Five-year amputation-free survival rates were highest using GSV conduit regardless of distal bypass target (log-rank P = 0.017). On a multivariable analysis, age (HR 1.02 [1.00-1.04], P = 0.023) and active smoking (HR 1.48 [1.06-2.06], P = 0.021) were identified as risk factors for diminished primary graft patency. Risk factors for amputation-free survival included age (HR 1.03 [1.01-1.05], P < 0.001) and GSV conduit type (HR 0.65 [0.46-0.90], P = 0.011). CONCLUSIONS: Femoropopliteal bypass among claudicants is associated with high rates of wound infection and hospital readmission. Active smoking portends worse outcomes in this population. These data may inform clinical decision-making regarding surgical intervention for claudication in the endovascular era.

Where to start? Injury prevention priority scores for traumatic injuries in Canada.

BACKGROUND: Given limited resources for injury prevention, it is essential to determine which mechanisms of injury to target to provide the most benefit to the largest proportion of the population. We developed objective, evidence-based injury prevention priority scores (IPPSs) for the Canadian population across 4 prevention perspectives: mortality, injury severity, resource use and societal cost. METHODS: We performed a retrospective cohort study of all injuries in Canada from 2009/10 to 2013/14. Hospital admissions were obtained from the Discharge Abstract Database, and deaths from the Statistics Canada Canadian Vital Statistics Death Database. For each mechanism of injury, we calculated an IPPS as a balanced measure of injury frequency and 1) mortality rate, 2) median 1 - ICISS (Injury Severity Score derived from the International Statistical Classification of Diseases and Related Health Problems, 10th revision, enhanced Canadian version), 3) median cost per hospital stay or 4) median potential years of life lost (PYLL), providing a ranking of mechanisms of injury in priority order. The IPPS by definition has a mean of 50 and a standard deviation of 10. The higher the IPPS, the higher the priority for injury prevention. RESULTS: A total of 694 535 injuries were identified over the study period. The most frequent mechanism of injury was falls (391 068 [56.3%]). The overall mortality rate was 0.09 deaths/injured person, the median 1 - ICISS was 0.017, the median cost was $5217, and the median PYLL was 0. The mechanisms with the 3 highest IPPSs were falls (75), self-harm (67) and drowning (66) for mortality; falls (77), drowning (70) and suffocation (61) for severity; falls (80), suffocation (63) and fire (60) for resource use; and falls (72), assault (62), and firearms and legal interventions (59 in both cases) for societal cost. CONCLUSION: This study produced IPPSs for traumatic injuries in Canada that provide objective and quantifiable methods for identifying mechanisms of injury to target for specific prevention initiatives. Preventing falls would provide the most benefit to the largest proportion of Canadians and should be prioritized in injury-prevention policy.

Safety and effectiveness of single ProGlide vascular access in patients undergoing endovascular aneurysm repair.

OBJECTIVE: The objective of this study was to evaluate the safety and effectiveness of single ProGlide use per bilateral access site for endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms. METHODS: A retrospective cohort study was performed for all elective percutaneous EVARs from November 2015 to December 2017 at the QEII Health Sciences Centre (Halifax, Nova Scotia, Canada). Exposure of interest was number of ProGlides used per access site, dichotomized into bilateral single ProGlide closure vs nonsingle ProGlide closure on at least one femoral arteriotomy. Outcomes included Valve Academic Research Consortium (VARC)-2 and Bleeding Academic Research Consortium (BARC) criteria. Groups were compared with Fisher exact test, analysis of variance, or Wilcoxon rank sum, as appropriate. Logistic regression was used to compare the effect of single ProGlide use on VARC-2 and BARC criteria. RESULTS: A total of 131 cases were included, of which 116 had bilateral single ProGlide use for access closure. Baseline characteristics including comorbidities and smoking status were compared between groups. Groups were similar for all characteristics except smoking status, with an increased proportion of former smokers in the nonsingle ProGlide group. There were 119 (90.8%) patients who had single ProGlide use on the right femoral artery and 121 (92.4%) on the left; 16 (12.2%) patients had ProGlide deployment issues. Median maximal right and left femoral sheath diameters were 16F (interquartile range [IQR], 16F-18F) and 14F (IQR, 14F-16F), respectively. Median length of stay was 1 day (IQR, 1-1 day). VARC-2 criteria occurred in 8 of 131 (6.11%) patients, 6 of 116 (5.17%) with bilateral single ProGlides and 2 of 15 (13.3%) with nonsingle ProGlides. BARC criteria occurred in 6 of 131 (4.58%) patients, 5 of 116 (4.31%) with bilateral single ProGlides and 1 of 15 (6.67%) with nonsingle ProGlides. Single ProGlide use was not associated with a difference in VARC-2 (odds ratio, 0.35; 95% confidence interval, 0.64-1.94) or BARC (odds ratio, 0.63; 95% confidence interval, 0.07-6.79) criteria. No patients developed pseudoaneurysms or required repeated intervention for bleeding. CONCLUSIONS: Single ProGlide use per vascular access site in patients undergoing EVAR is a safe and effective method for access closure with sheath diameters up to and including 16F.

Surgically positioned paravertebral catheters and postoperative analgesia after open abdominal aortic aneurysm repair.

OBJECTIVE: To compare postoperative morphine equivalent intake after open abdominal aortic aneurysm (AAA) repair among analgesic modalities: systemic analgesia (SA) only with no regional anesthesia, surgically positioned paravertebral catheter (PVC), and thoracic epidural analgesia (TEA). METHODS: This retrospective cohort study included patients undergoing elective open AAA at the Queen Elizabeth II Health Science Center, Halifax, Nova Scotia. Demographics, morphine equivalents, methods of analgesia administration, and outcomes data were collected on all patients from 2005 to 2016. Total morphine equivalent (MEQ) on postoperative days (PODs) 1, 2, and 3 were compared among patients with SA, PVC, and TEA. A multivariable zero-inflated log-linear regression was used to determine the association between analgesic modality and MEQ. Multivariable logistic regression models were used to determine associations between analgesic modality and postoperative pain, rates of discharge from intensive care within 1 day and opioid-related adverse events. RESULTS: The study cohort included 355 patients: 177 retroperitoneal and 178 transperitoneal repairs; 173 patients underwent SA, 117 PVC, and 65 TEA. On POD1, median MEQs were 984 (interquartile range [IQR], 342-1525) for SA, 89 (33-246) for PVC, and 49 (0-90) for TEA. On POD2, the median MEQs were 105 (IQR, 57-210) for SA, 45 (15-99) for PVC, and 30 (0-64) for TEA. On POD3, the median MEQs were 45 (IQR, 15-120) for SA, 30 (0-60) for PVC, and 10 (0-45) for TEA. On multivariable log-linear regression, compared with SA, PVC and TEA were associated with increased odds of receiving no opioids on POD1 (odds ratio [OR], 66.85; 95% confidence interval [CI], 17.49-255.57; and OR, 214.68; 95% CI, 60.20-766.38; respectively), POD 2 (OR, 6.97; 95% CI, 3.61-13.46; and OR, 28.73; 95% CI, 15.68-52.62; respectively), and POD 3 (OR, 3.93; 95% CI, 2.72-5.67; and OR, 4.68; 95% CI, 3.20-6.86; respectively). If patients did receive opioids, compared with SA, PVC and TEA were associated with decreased consumption on POD1 (RR, 0.22; 95% CI, 0.18-0.27; and RR, 0.16; 95% CI, 0.12-0.20; respectively), POD2 (RR, 0.50; 95% CI, 0.42-0.58; and RR, 0.46; 95% CI, 0.37-0.56; respectively), and POD3 (RR, 0.78; 95% CI, 0.66-0.93; and RR, 0.76; 95% CI, 0.63-0.93; respectively). Compared with SA, PVC was associated with earlier discharge from intensive care (OR, 2.75; 95% CI, 1.17-6.45) and TEA was not (OR, 1.12; 95% CI, 0.56-2.2). Compared with TEA, PVC was not associated with increased rate of opioid-related adverse events (OR, 0.44; 95% CI, 0.08-2.44). CONCLUSIONS: PVC and TEA are associated with decreased MEQ compared with SA. PVC is associated with earlier discharge from intensive care compared with SA and similar rates of opioid-related adverse events compared with TEA. Paravertebral analgesia appears to be a safe and effective analgesic modality in patients undergoing retroperitoneal approach for abdominal aneurysm repair.

Crash testing the dummy: a review of in situ trauma simulation at a Canadian tertiary centre

Background: In situ trauma simulations allow for the trauma team and emergency department to practise team dynamics, resuscitation and logistics in a safe environment. The goal of this investigation was to show the feasibility of an in situ trauma simulation program at a Canadian level 1 trauma centre. Methods: We performed a retrospective review of in situ simulations (maximum 20 min, followed by a 10-min debriefing session) at a level 1 trauma centre from 2015 to 2017. Errors were categorized according to the National Patient Safety Agency risk assessment matrix by 3 independent raters and assigned consequence scores (assessing potential harm) and likelihood scores (assessing the likelihood of potential harm). A risk score was calculated as the product of the mean consequence and likelihood scores. Errors per simulation and the number of simulations required for error resolution were recorded. Results: We reviewed 8 in situ simulations and identified 54 errors, of which 7 were related to medications, 20 to equipment, 21 to environment/staffing and 6 to training. The mean consequence score was 2.85/5 (standard deviation [SD] 0.75, intraclass correlation coefficient [ICC] 28%), indicating minor to moderate harm. The mean likelihood score was 2.82/5 (SD 0.55, ICC 41%), indicating unlikely to possible. The mean risk score was 8.42/25 (SD 3.19, ICC 43%). One error (2%) was low risk, 23 (43%) were moderate risk, 26 (48%) were high risk, and 4 (7%) were extreme risk. Conclusion: In situ trauma simulations are feasible in a Canadian centre and provide a safe environment to identify and rectify errors.

Contexte: Les simulations de catastrophes in situ permettent à l'équipe de traumatologie et au service d'urgence de tester la dynamique d'équipe, les techniques de réanimation et la logistique dans un environnement sécuritaire. L'objectif de cette étude était de montrer la faisabilité d'un programme de simulation in situ dans un centre canadien de traumatologie de niveau 1. Méthodes: Nous avons effectué une revue rétrospective des simulations in situ (maximum 20 min, suivies de séances de compte rendu) ayant eu lieu dans un centre de traumatologie de niveau 1 entre 2015 et 2017. Les erreurs ont été classées en catégories selon la grille d'évaluation des risques de la National Patient Safety Agency par 3 examinateurs indépendants, qui leur ont assigné des scores de conséquence (préjudices potentiels) et des scores de probabilité (probabilité de préjudices potentiels). Un score de risque a été calculé sous forme de produit des scores moyens de conséquence et de probabilité. Le nombre d'erreurs par simulation et le nombre des simulations requises pour les résoudre ont été enregistrés. Résultats: Nous avons analysé 8 simulations in situ et relevé 54 erreurs, dont 7 concernaient les médicaments, 20, l'équipement, 21, l'environnement ou la dotation en personnel et 6, la formation. Le score de conséquence moyen était de 2,85/5 (écarttype 0,75; coefficient de corrélation intraclasse [CCI] 28 %), indiquant des préjudices de mineurs à modérés. Le score de probabilité moyen était de 2,82/5 (écart-type 0,55; CCI 41 %), soit d'improbable à possible. Le score de risque moyen était donc de 8,42/25 (écart-type 3,19; CCI 43 %). Une seule erreur (2 %) comportait un risque faible, 23 (43 %) comportaient un risque modéré, 26 (48 %), un risque élevé et 4 (7 %), un risque extrême. Conclusion: Les simulations de catastrophes in situ sont faisables dans un centre canadien et permettent d'identifier les erreurs et les rectifier dans un environnement sécuritaire.

Intraoperative insertion of paravertebral catheter for postoperative analgesia in retroperitoneal aortic aneurysm repair.

Paravertebral catheters are a well-established analgesic modality in thoracic surgery but have not been described in abdominal aortic surgery. We describe a simple, safe, and effective technique of paravertebral catheter insertion by the operative surgeon after a retroperitoneal abdominal aortic aneurysm repair. Once the aneurysm repair is complete, an extrapleural plane between the parietal pleura and the twelfth rib is created through blunt dissection. A catheter is advanced into the space percutaneously under direct vision, and a continuous infusion of local anesthetic is administered. Paravertebral catheters typically remain in place for 3 to 5 days and provide excellent postoperative non-narcotic analgesia.