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Racial Disparities after Vascular Trauma Are Age-Dependent
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J Am Coll Surg
Scientific Forum Abstracts
preoperative AP-S use by univariate, stratified and multivariate logistic regression analyses. RESULTS: Only 60.8% of 9871 patients were on preoperative AP-S therapy. Significantly lower use was seen in CLI patients vs claudicants (58.6% vs 64.3%, p<0.001) overall and across procedure subtypes (Table). After controlling for patient and operative factors, preoperative AP-S therapy was associated with a significantly lower risk of amputation (odds ratio [OR] 0.71, 95% CI [0.52-0.98]) when compared with those not on AP-S therapy. On stratification in multivariate analysis, the risk reduction stayed significant in patients with CLI (OR 0.72, 95% CI [0.53-1.0]) but not in claudicants (OR 2.05, 95% CI [0.59-8.18]). AP-S therapy was also associated with decreased graft/treatment failure in CLI patients (OR 0.63, 95% CI [0.59-1.02]) but not in claudicants. Table. Anti-Platelet and Statin Use by Lower Extremity Procedure Type and Claudication vs Critical Limb Ischemia Lower extremity procedure
Suprainguinal endovascular Suprainguinal open Infrainguinal endovascular Infrainguinal open All endovascular procedures All open procedures Total
n (%)
Percentage of patients on AP-S Claudication CLI p Value
961 (9.7) 1,420 (24.1)
64.2 63.3
57.2 0.03 54.5 <0.001
2,884 (29.2) 4,606 (46.7)
68.4 60.1
58.8 <0.001 59.7 0.3
3,845 (38.9) 6,026 (61.1) 9,871 (100)
66.9 59.5 64.3
58.5 <0.001 58.7 0.01 58.6 <0.001
AP-S, antiplatelet and statin; CLI, critical limb ischemia.
CONCLUSIONS: Our study shows significant underutilization of AP-S therapy in PAD revascularization procedures, especially in CLI patients. Furthermore, AP-S therapy was associated with lower risk of postoperative amputation and graft/treatment failure in the CLI population, suggesting an enormous potential for quality improvement in lower extremity revascularization outcomes. Purinergic Signaling Promotes Macrophage Differentiation to Foam Cells Kenneth W Howell, MD*, Joseph C Cleveland Jr, MD, FACS University of Colorado-Anschutz Medical Campus, Aurora, CO INTRODUCTION: Macrophage foam cells are central in the development of atherosclerosis but the root cause of foam cell formation is unclear. Macrophage foam cells tend to form in clusters in vivo and in vitro. Macrophages communicate with each other in a paracrine manner using purinergic signaling. We hypothesized that purinergic signaling modulates macrophage differentiation to foam cells. METHODS: RAW 264.7 macrophages were treated with oxidized LDL (oxLDL). Purinergic signaling was blocked using a nonspecific purinergic receptor antagonist suramin. Purinergic signaling was promoted by adding purine nucleotides to the cell culture
medium. Oil red O staining for intracellular lipids was used for identification of foam cells. Statistical analysis was performed using ANOVA. RESULTS: Blockade of purinergic signaling decreased macrophage differentiation to foam cells. After treatment with oxLDL alone, 21% of macrophages differentiated to foam cells and foam cells formed in clusters of 8-20 cells. Treatment with a purinergic receptor antagonist in addition to oxLDL decreased the differentiation of macrophages to foam cells from 21% to 4% (p<0.01). Macrophage foam cells that formed in the presence of the purinergic receptor antagonist formed in isolation. Treatment with purine nucleotides in addition to oxLDL increased the differentiation of macrophages to foam cells from 21% to 45% (p<0.01). Macrophage foam cell cluster size increased to greater than 20 cells per cluster when treated with purine nucleotides. CONCLUSIONS: Purinergic signaling promotes macrophage differentiation to foam cells and foam cell clustering. We conclude that purinergic signaling contributes to the pathogenesis of atherosclerosis by promoting foam cell formation and foam cell clustering. Racial Disparities after Vascular Trauma Are AgeDependent Caitlin W Hicks, MD, Joseph K Canner, MHS, Devin S Zarkowsky, MD, Eric B Schneider, PhD, Isibor Arhuidese, MD, MPH, Tammam Obeid, MD, Umair Qazi, MD, MPH, Christopher J Abularrage, MD, FACS, Mahmoud Malas, MD, MHS, FACS Johns Hopkins Medical Institute, Baltimore, MD INTRODUCTION: Racial disparities in survival after all-cause trauma exist between white and black patients. However, the effects of race stratified by age on outcomes after vascular trauma are unknown. METHODS: Vascular trauma patients were identified from the Nationwide Inpatient Sample (January 2003-December 2010) using ICD-9 codes. In-hospital mortality and amputation were compared for blacks vs whites for younger (16-64 years) and older (65 years) age groups using univariable and multivariable analyses. RESULTS: Black patients (n¼937) were younger, more frequently male, without insurance, and suffered from more penetrating and non-accidental injuries compared with white patients (n¼1,486) (p<0.001). On univariable analysis, blacks had a significantly higher risk of death (odds ratio [OR] 1.78) and a significantly lower risk of amputation (OR 0.54), but these differences were not sustained after correcting for baseline differences between groups. When stratified by age, there were significant racial disparities in both mortality and amputation in the older age group, but not in the younger age group (Table). Differences in both survival and amputation after vascular trauma appear to be related to a higher prevalence of non-accidental penetrating injuries in the
Vol. 221, No. 4S1, October 2015
younger black population. Race was the single greatest predictor in the older group (p0.008).
Patient group
Overall < 65 years of age 65 years of age
Black vs white odds ratio (95% CI) Unadjusted Adjustedy Mortality Amputation Mortality Amputation
1.78 0.54 1.80 1.17 (1.16-2.74)* (0.38-0.77)* (0.96-3.38) (0.76-1.82) 1.98 0.48 1.31 0.92 (1.22-3.20)* (0.32-0.70)* (0.71-2.42) (0.58-1.46) 4.15 4.09 5.95 4.21 (1.28-13.4)* (1.37-12.2)* (1.42-25.0)* (1.28-13.6)*
*p <0.05. y Adjusted for age, sex, insurance status, Charlson comorbidity index, injury type (penetrating vs blunt, injury intent, and injury severity.
CONCLUSIONS: Older black patients are nearly 5 times more likely to experience death or amputation after vascular trauma than their white counterparts. Contrary to reports suggesting that younger white patients have better outcomes after all-cause trauma than younger black patients, racial disparities among patients with traumatic vascular injuries appear to be confined to the older age group after risk adjustment. Rehabilitation Outcomes after Lower-Extremity Amputations in Canada Ahmed Kayssi, MD, MPH, FRCSC, Derry L Dance, MD, MPH, JD, FRCPC, Charles De Mestral, MD, Thomas L Forbes, MD, FRCSC, FACS, Graham Roche-Nagle, MD, MBA, FRCSI University of Toronto, Toronto, ON INTRODUCTION: The aim of this study was to describe trends in rehabilitation after lower-extremity amputations and the factors affecting rehabilitation length of stay in Canada. METHODS: A retrospective cohort analysis was carried out of Canadian adults undergoing elective lower-extremity amputations between 2006 and 2009 for non-traumatic indications and discharged to a rehabilitation facility. Patients were identified from the Canadian Institute for Health Information’s Discharge Abstract Database, which includes hospital admissions across Canada, except Quebec. RESULTS: The analysis included 5,342 patients who underwent lower limb amputations, 1,904 of whom were transferred to a rehabilitation facility (35.6%). The most common reasons for rehabilitation were below-knee (74.2%) and above-knee (16.6%) amputations. The average duration of rehabilitation varied by whether the amputation was performed by a vascular (mean¼ 40.2 26.4 days), orthopaedic (mean¼ 42.7 31.2 days), or general surgeon (mean¼ 39.3 25.5 days). Most patients (71.9%) were subsequently discharged home, and a minority (9.4%) were readmitted to hospital. Predictors of longer rehabilitation included amputation by an orthopaedic surgeon (Beta¼5.0, p¼<0.01), older age (Beta¼0.2, p¼<0.01), and a history of ischemic heart disease (Beta¼3.8, p¼0.03) or congestive heart failure (Beta¼5, p¼0.04). Conversely, patients who spent fewer than 7 days in
Scientific Forum Abstracts
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hospital were significantly more likely to have a shorter rehabilitation stay (Beta ¼ -4, p¼0.03). CONCLUSIONS: Rehabilitation length of stay after major lowerextremity amputation varies by the type of surgeon performing the amputation. A shorter perioperative hospitalization period predicts a shorter rehabilitation stay. Differences between provider specialties are likely due to unstudied systems issues, rather than technical considerations. Repair of Lower Extremity Arterial Injuries: “A Race Against Time” Abdul Q Alarhayem, MD, Brian J Eastridge, MD, FACS, John G Myers, MD, FACS, Nathan S Rubalcava, MD, Stephen M Cohn, MD, FACS University of Texas Health Science Center at San Antonio, San Antonio, TX INTRODUCTION: Six hours has long been considered the threshold of ischemia after lower extremity arterial injury (LAI). However, there is a paucity of evidence regarding the impact of operative delays on morbidity in patients with LAI. We sought to determine the relationship of therapeutic delay after LAI to the development of major complications (defined as amputation or compartment syndrome necessitating fasciotomy). METHODS: We reviewed patients with LAI brought directly to our level I trauma center from injury scene from 2000-2015. National Trauma Data Bank (NTDB) data from 2012 for LAI were also analyzed. Patients with mangled extremities, lower extremity nerve injury, or vascular injuries managed nonoperatively were excluded. RESULTS: There were 115 patients with LAI who fulfilled inclusion criteria; 73% sustained blunt trauma. Median injury to operating room arrival time was 238 minutes. Six patients died from associated injuries, 4 had amputations from vascular failure. Fifty-one patients underwent fasciotomies (30 of which were prophylactic). Patients undergoing vascular repair within 60 minutes had a lower rate of major complications vs those undergoing delayed repair. (1/7, 14% vs 24/ 108, 22%). There were 1,685 LAI identified from the NTDB; there was a statistically significant increase in the rate of amputation when time from injury to operative intervention exceeded 1 hour (14% <60 minutes vs 23% > 60 minutes; p <0.05). CONCLUSIONS: Delays in the management of lower extremity arterial injuries increase the rate of major extremity complications. Data from this analysis support the requirement for expeditious intervention to restore arterial prograde flow in patients with peripheral arterial injury. Short-Term Quality of Care Outcomes of Tunneled Dialysis Catheters, Arteriovenous Fistula, Arteriovenous Graft, and Early Cannulation Dialysis Access Sapan S Desai, MD, PhD, MBA, Anahita Dua, MD, Charles D Callahan, PhD, MBA Southern Illinois University, Springfield, IL, Memorial Medical Center, Springfield, IL
J Am Coll Surg
Scientific Forum Abstracts
preoperative AP-S use by univariate, stratified and multivariate logistic regression analyses. RESULTS: Only 60.8% of 9871 patients were on preoperative AP-S therapy. Significantly lower use was seen in CLI patients vs claudicants (58.6% vs 64.3%, p<0.001) overall and across procedure subtypes (Table). After controlling for patient and operative factors, preoperative AP-S therapy was associated with a significantly lower risk of amputation (odds ratio [OR] 0.71, 95% CI [0.52-0.98]) when compared with those not on AP-S therapy. On stratification in multivariate analysis, the risk reduction stayed significant in patients with CLI (OR 0.72, 95% CI [0.53-1.0]) but not in claudicants (OR 2.05, 95% CI [0.59-8.18]). AP-S therapy was also associated with decreased graft/treatment failure in CLI patients (OR 0.63, 95% CI [0.59-1.02]) but not in claudicants. Table. Anti-Platelet and Statin Use by Lower Extremity Procedure Type and Claudication vs Critical Limb Ischemia Lower extremity procedure
Suprainguinal endovascular Suprainguinal open Infrainguinal endovascular Infrainguinal open All endovascular procedures All open procedures Total
n (%)
Percentage of patients on AP-S Claudication CLI p Value
961 (9.7) 1,420 (24.1)
64.2 63.3
57.2 0.03 54.5 <0.001
2,884 (29.2) 4,606 (46.7)
68.4 60.1
58.8 <0.001 59.7 0.3
3,845 (38.9) 6,026 (61.1) 9,871 (100)
66.9 59.5 64.3
58.5 <0.001 58.7 0.01 58.6 <0.001
AP-S, antiplatelet and statin; CLI, critical limb ischemia.
CONCLUSIONS: Our study shows significant underutilization of AP-S therapy in PAD revascularization procedures, especially in CLI patients. Furthermore, AP-S therapy was associated with lower risk of postoperative amputation and graft/treatment failure in the CLI population, suggesting an enormous potential for quality improvement in lower extremity revascularization outcomes. Purinergic Signaling Promotes Macrophage Differentiation to Foam Cells Kenneth W Howell, MD*, Joseph C Cleveland Jr, MD, FACS University of Colorado-Anschutz Medical Campus, Aurora, CO INTRODUCTION: Macrophage foam cells are central in the development of atherosclerosis but the root cause of foam cell formation is unclear. Macrophage foam cells tend to form in clusters in vivo and in vitro. Macrophages communicate with each other in a paracrine manner using purinergic signaling. We hypothesized that purinergic signaling modulates macrophage differentiation to foam cells. METHODS: RAW 264.7 macrophages were treated with oxidized LDL (oxLDL). Purinergic signaling was blocked using a nonspecific purinergic receptor antagonist suramin. Purinergic signaling was promoted by adding purine nucleotides to the cell culture
medium. Oil red O staining for intracellular lipids was used for identification of foam cells. Statistical analysis was performed using ANOVA. RESULTS: Blockade of purinergic signaling decreased macrophage differentiation to foam cells. After treatment with oxLDL alone, 21% of macrophages differentiated to foam cells and foam cells formed in clusters of 8-20 cells. Treatment with a purinergic receptor antagonist in addition to oxLDL decreased the differentiation of macrophages to foam cells from 21% to 4% (p<0.01). Macrophage foam cells that formed in the presence of the purinergic receptor antagonist formed in isolation. Treatment with purine nucleotides in addition to oxLDL increased the differentiation of macrophages to foam cells from 21% to 45% (p<0.01). Macrophage foam cell cluster size increased to greater than 20 cells per cluster when treated with purine nucleotides. CONCLUSIONS: Purinergic signaling promotes macrophage differentiation to foam cells and foam cell clustering. We conclude that purinergic signaling contributes to the pathogenesis of atherosclerosis by promoting foam cell formation and foam cell clustering. Racial Disparities after Vascular Trauma Are AgeDependent Caitlin W Hicks, MD, Joseph K Canner, MHS, Devin S Zarkowsky, MD, Eric B Schneider, PhD, Isibor Arhuidese, MD, MPH, Tammam Obeid, MD, Umair Qazi, MD, MPH, Christopher J Abularrage, MD, FACS, Mahmoud Malas, MD, MHS, FACS Johns Hopkins Medical Institute, Baltimore, MD INTRODUCTION: Racial disparities in survival after all-cause trauma exist between white and black patients. However, the effects of race stratified by age on outcomes after vascular trauma are unknown. METHODS: Vascular trauma patients were identified from the Nationwide Inpatient Sample (January 2003-December 2010) using ICD-9 codes. In-hospital mortality and amputation were compared for blacks vs whites for younger (16-64 years) and older (65 years) age groups using univariable and multivariable analyses. RESULTS: Black patients (n¼937) were younger, more frequently male, without insurance, and suffered from more penetrating and non-accidental injuries compared with white patients (n¼1,486) (p<0.001). On univariable analysis, blacks had a significantly higher risk of death (odds ratio [OR] 1.78) and a significantly lower risk of amputation (OR 0.54), but these differences were not sustained after correcting for baseline differences between groups. When stratified by age, there were significant racial disparities in both mortality and amputation in the older age group, but not in the younger age group (Table). Differences in both survival and amputation after vascular trauma appear to be related to a higher prevalence of non-accidental penetrating injuries in the
Vol. 221, No. 4S1, October 2015
younger black population. Race was the single greatest predictor in the older group (p0.008).
Patient group
Overall < 65 years of age 65 years of age
Black vs white odds ratio (95% CI) Unadjusted Adjustedy Mortality Amputation Mortality Amputation
1.78 0.54 1.80 1.17 (1.16-2.74)* (0.38-0.77)* (0.96-3.38) (0.76-1.82) 1.98 0.48 1.31 0.92 (1.22-3.20)* (0.32-0.70)* (0.71-2.42) (0.58-1.46) 4.15 4.09 5.95 4.21 (1.28-13.4)* (1.37-12.2)* (1.42-25.0)* (1.28-13.6)*
*p <0.05. y Adjusted for age, sex, insurance status, Charlson comorbidity index, injury type (penetrating vs blunt, injury intent, and injury severity.
CONCLUSIONS: Older black patients are nearly 5 times more likely to experience death or amputation after vascular trauma than their white counterparts. Contrary to reports suggesting that younger white patients have better outcomes after all-cause trauma than younger black patients, racial disparities among patients with traumatic vascular injuries appear to be confined to the older age group after risk adjustment. Rehabilitation Outcomes after Lower-Extremity Amputations in Canada Ahmed Kayssi, MD, MPH, FRCSC, Derry L Dance, MD, MPH, JD, FRCPC, Charles De Mestral, MD, Thomas L Forbes, MD, FRCSC, FACS, Graham Roche-Nagle, MD, MBA, FRCSI University of Toronto, Toronto, ON INTRODUCTION: The aim of this study was to describe trends in rehabilitation after lower-extremity amputations and the factors affecting rehabilitation length of stay in Canada. METHODS: A retrospective cohort analysis was carried out of Canadian adults undergoing elective lower-extremity amputations between 2006 and 2009 for non-traumatic indications and discharged to a rehabilitation facility. Patients were identified from the Canadian Institute for Health Information’s Discharge Abstract Database, which includes hospital admissions across Canada, except Quebec. RESULTS: The analysis included 5,342 patients who underwent lower limb amputations, 1,904 of whom were transferred to a rehabilitation facility (35.6%). The most common reasons for rehabilitation were below-knee (74.2%) and above-knee (16.6%) amputations. The average duration of rehabilitation varied by whether the amputation was performed by a vascular (mean¼ 40.2 26.4 days), orthopaedic (mean¼ 42.7 31.2 days), or general surgeon (mean¼ 39.3 25.5 days). Most patients (71.9%) were subsequently discharged home, and a minority (9.4%) were readmitted to hospital. Predictors of longer rehabilitation included amputation by an orthopaedic surgeon (Beta¼5.0, p¼<0.01), older age (Beta¼0.2, p¼<0.01), and a history of ischemic heart disease (Beta¼3.8, p¼0.03) or congestive heart failure (Beta¼5, p¼0.04). Conversely, patients who spent fewer than 7 days in
Scientific Forum Abstracts
S183
hospital were significantly more likely to have a shorter rehabilitation stay (Beta ¼ -4, p¼0.03). CONCLUSIONS: Rehabilitation length of stay after major lowerextremity amputation varies by the type of surgeon performing the amputation. A shorter perioperative hospitalization period predicts a shorter rehabilitation stay. Differences between provider specialties are likely due to unstudied systems issues, rather than technical considerations. Repair of Lower Extremity Arterial Injuries: “A Race Against Time” Abdul Q Alarhayem, MD, Brian J Eastridge, MD, FACS, John G Myers, MD, FACS, Nathan S Rubalcava, MD, Stephen M Cohn, MD, FACS University of Texas Health Science Center at San Antonio, San Antonio, TX INTRODUCTION: Six hours has long been considered the threshold of ischemia after lower extremity arterial injury (LAI). However, there is a paucity of evidence regarding the impact of operative delays on morbidity in patients with LAI. We sought to determine the relationship of therapeutic delay after LAI to the development of major complications (defined as amputation or compartment syndrome necessitating fasciotomy). METHODS: We reviewed patients with LAI brought directly to our level I trauma center from injury scene from 2000-2015. National Trauma Data Bank (NTDB) data from 2012 for LAI were also analyzed. Patients with mangled extremities, lower extremity nerve injury, or vascular injuries managed nonoperatively were excluded. RESULTS: There were 115 patients with LAI who fulfilled inclusion criteria; 73% sustained blunt trauma. Median injury to operating room arrival time was 238 minutes. Six patients died from associated injuries, 4 had amputations from vascular failure. Fifty-one patients underwent fasciotomies (30 of which were prophylactic). Patients undergoing vascular repair within 60 minutes had a lower rate of major complications vs those undergoing delayed repair. (1/7, 14% vs 24/ 108, 22%). There were 1,685 LAI identified from the NTDB; there was a statistically significant increase in the rate of amputation when time from injury to operative intervention exceeded 1 hour (14% <60 minutes vs 23% > 60 minutes; p <0.05). CONCLUSIONS: Delays in the management of lower extremity arterial injuries increase the rate of major extremity complications. Data from this analysis support the requirement for expeditious intervention to restore arterial prograde flow in patients with peripheral arterial injury. Short-Term Quality of Care Outcomes of Tunneled Dialysis Catheters, Arteriovenous Fistula, Arteriovenous Graft, and Early Cannulation Dialysis Access Sapan S Desai, MD, PhD, MBA, Anahita Dua, MD, Charles D Callahan, PhD, MBA Southern Illinois University, Springfield, IL, Memorial Medical Center, Springfield, IL