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Vascular Surgery: An Essential Hospital Resource in Modern Health Care
JOURNAL OF VASCULAR SURGERY Volume 64, Number 2
The Impact of Statin Therapy on the Primary Patency of Femoral and Popliteal Artery Stents Derek de Grijs, MD,1 Pedro Teixeira, MD,2 Steven G. Katz, MD3. 1 Department of Surgery, Huntington Memorial Hospital, Pasadena, Calif; 2 Department of Surgery and Perioperative Care, University of Texas at Austin Dell Medical School, Austin, Tex; 3Division of Vascular Surgery and Endovascular Surgery, Keck School of Medicine, University of Southern California, Los Angeles, Calif Objective: It has long been known that hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) broadly reduce cardiovascular events in patients with peripheral vascular disease. It was the goal of this study to determine if statin therapy significantly improves primary patency rates after stenting of superficial femoral and popliteal arteries. Methods: The records of all patients undergoing primary nitinol stenting of the femoral and popliteal arteries at a single institution and by a single surgeon during a 7-year period were reviewed. Patient demographics and risk factors were identified. TransAtlantic Inter-Society Consensus (TASC II) classifications were determined for all stented lesions to stratify severity of disease. Analysis was performed to determine whether the use of statins at the time of stent placement influenced patency. Loss of primary patency was said to have occurred when an intrastent occlusion or a 50% or greater stenosis was identified by arterial duplex ultrasound or angiography. Kaplan-Meier survival curves were plotted, and differences between groups were tested by log-rank method. Results: Between 2007 and 2014, primary femoral or popliteal stenting was performed on 162 limbs in 141 patients. At the time of intervention, 55.5% of these patients were being treated with statin therapy. There were 88 interventions performed for claudication and 74 for critical limb ischemia; 107 lesions treated were TASC A or B, and 55 were TASC C or D. Primary patency rates for all stented lesions was 68%, 53%, and 43% at 12, 24, and 36 months. Those taking statins had patency rates of 75%, 58%, and 47%, whereas the patency rates for those not taking statins were 55%, 45%, and 36% at 12, 24, and 36 months, respectively (P ¼ .179). Statins had no significant influence on patency rates when lesions were stratified for severity (TASC A/B, P ¼ .162; C/D, P ¼ .638). There was no significant difference in those treated for claudication or critical limb ischemia (P ¼ .929). Statin compliance was found to be 86% at a mean follow-up of 23.6 months. Conclusions: Whereas the use of statins has been shown to reduce cardiovascular morbidity and mortality in patients with peripheral vascular disease, the ability of these drugs to improve primary patency rates of patients after superficial femoral and popliteal artery stenting remains speculative. Vascular Surgery: An Essential Hospital Resource in Modern Health Care Miguel F. Manzur, MD, Sung W. Ham, MD, Ramsey S. Elsayed, MD, Trevor Simcox, BS, Fred A. Weaver, MD, MMM. Keck School of Medicine of USC, Los Angeles, Calif Objective: Vascular surgeons are consulted by other surgical specialties for intraoperative vascular exposure, reconstruction, or hemorrhage control. These requests occur both electively and emergently. We analyzed the value of vascular surgery operative services as a resource to other surgical specialties at our institution. Methods: Intraoperative elective and emergent vascular surgery consultations requiring operative intervention were reviewed during a 3-year period (2013-2016). Patient demographics, requesting surgical specialty, indication for and type of vascular operative intervention, and work relative value units generated for the intervention were recorded. Results: Seventy-six patients required vascular surgery intraoperative consultations for operative intervention. Operative interventions were emergent in 57% and elective in 43%. The most common elective intervention was oncologic vascular reconstruction; the most common emergency intervention was hemorrhage control during oncologic resection. Vascular beds included the lower extremity (35%), aorta and its major branches (33%), inferior vena cava and major venous structures (19%), vessels of the head and neck (7%), and upper extremity (6%). Requesting surgical specialties were cardiac (24%), urology (18%), orthopedics (17%), hepatobiliary/transplantation (16%), and others (25%). Reasons for consultation were vascular reconstruction (30%), dissection requiring vascular exposure (21%), hemorrhage control (20%), acute limb ischemia (15%), and access difficulties (14%). The types of repairs were primary vessel repair (32%), interposition grafts (28%), bypass (21%), and others (19%). Ninety-nine percent (75/76) of cases were completed after vascular assistance. In-hospital mortality was 10.5%
Abstracts 543
(8/76), none related to vascular intervention. Mean work relative value units generated per vascular surgery intervention were 22.3. Conclusions: The availability of vascular surgeons ensures the successful completion of technically challenging operations performed by other surgical specialties. Furthermore, intraoperative vascular surgery services are frequent in both elective and emergent settings and involve a variety of vascular beds. Vascular surgery is an essential hospital resource in the modern health care environment. Intraluminal Thrombus Is Associated With Aortic Wall Weakening in Small Ruptured Abdominal Aortic Aneurysms Jeffrey D. Crawford, MD, Stephen J. Haller, BS, Gregory J. Landry, MD, Cherrie Abraham, MD, Gregory L. Moneta, MD, Sandra Rugonyi, PhD, Amir F. Azarbal, MD. Oregon Health and Sciences University, Portland, Ore Objectives: Intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) has been shown to provide a biomechanical advantage by decreasing peak wall stress (PWS) while also acting as a nidus of inflammation and resultant aortic wall degeneration. In this study, we sought to explore the association between ILT and the risk of AAA rupture in small, high-risk aneurysms. Methods: Patients treated at our institution from 2001 to 2014 for ruptured AAA (rAAA) were retrospectively identified. Patients with small rAAA (<60 mm) with high-resolution computed tomography angiography available for study were included. These patients were considered to have high-risk aneurysms, given that they ruptured at relatively small AAA diameters. For comparison, a low-risk cohort of patients with large non-rAAA ($60 mm) with high-resolution preoperative computed tomography angiography were sequentially identified. Three-dimensional AAA anatomy was digitally reconstructed for each patient, and ILT percentage volume was computed (ILT percentage volume ¼ (volume ILT/[volume ILT + volume lumen]) 100). Finite element analysis was then performed to calculate AAA mean wall stress (MWS) and PWS distributions for each patient. Results: Patient demographics and results are summarized in Table. Patients with small rAAA had greater ILT percentage volume compared with patients with large non-rAAA (69 6 12% vs 57 6 12%; P ¼ .02) (Fig, A). Patients with small rAAA had lower MWS (47 6 17 kPa vs 72 6 19 kPa; P ¼ .003) and PWS (119 6 40 kPa vs 237 6 96 kPa; P < .001) compared with patients with large non-rAAA (Fig, B). Increased ILT percentage volume was associated with both decreased MWS and decreased PWS (Fig, C and D). Conclusions: Although increased ILT percentage volume is associated with lower MWS and PWS, it is also associated with rAAA at smaller diameters. Therefore, the protective biomechanical advantage of ILT in lowering PWS seems to be outweighed by weakening of the aortic wall in patients with small rAAA. Increased ILT percentage volume may be a surrogate marker for decreased aortic wall strength and a marker of high-risk AAAs.
Table. Patient demographics and results summary
AAA diameter, mm Age, years Male Hypertension Smoker ILT volume, mL ILT percentage volume, % Mean ILT thickness, mm MWS, kPa PWS, kPa
Large non-rAAA (n ¼ 15)
Small rAAA (n ¼ 9)
P
68.1 6 11.9 70.8 6 9.7 13 (86.7) 9 (60.0) 15 (100.0) 161 6 79 56.7 6 11.6 8.1 6 2.3 72 6 19 273 6 96
52.1 6 7.6 67.9 6 5.7 6 (66.7) 8 (88.9) 9 (100.0) 92 6 32 68.8 6 11.6 8.4 6 2.3 47 6 17 119 6 40
.002 NS NS NS NS .007 .022 NS .003 <.001
AAA, Abdominal aortic aneurysm; ILT, intraluminal thrombus; MWS, mean wall stress; NS, not significant; PWS, peak wall stress; rAAA, ruptured AAA. Continuous variables are presented as mean 6 standard deviation and categorical variables are presented as number (%).
The Impact of Statin Therapy on the Primary Patency of Femoral and Popliteal Artery Stents Derek de Grijs, MD,1 Pedro Teixeira, MD,2 Steven G. Katz, MD3. 1 Department of Surgery, Huntington Memorial Hospital, Pasadena, Calif; 2 Department of Surgery and Perioperative Care, University of Texas at Austin Dell Medical School, Austin, Tex; 3Division of Vascular Surgery and Endovascular Surgery, Keck School of Medicine, University of Southern California, Los Angeles, Calif Objective: It has long been known that hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) broadly reduce cardiovascular events in patients with peripheral vascular disease. It was the goal of this study to determine if statin therapy significantly improves primary patency rates after stenting of superficial femoral and popliteal arteries. Methods: The records of all patients undergoing primary nitinol stenting of the femoral and popliteal arteries at a single institution and by a single surgeon during a 7-year period were reviewed. Patient demographics and risk factors were identified. TransAtlantic Inter-Society Consensus (TASC II) classifications were determined for all stented lesions to stratify severity of disease. Analysis was performed to determine whether the use of statins at the time of stent placement influenced patency. Loss of primary patency was said to have occurred when an intrastent occlusion or a 50% or greater stenosis was identified by arterial duplex ultrasound or angiography. Kaplan-Meier survival curves were plotted, and differences between groups were tested by log-rank method. Results: Between 2007 and 2014, primary femoral or popliteal stenting was performed on 162 limbs in 141 patients. At the time of intervention, 55.5% of these patients were being treated with statin therapy. There were 88 interventions performed for claudication and 74 for critical limb ischemia; 107 lesions treated were TASC A or B, and 55 were TASC C or D. Primary patency rates for all stented lesions was 68%, 53%, and 43% at 12, 24, and 36 months. Those taking statins had patency rates of 75%, 58%, and 47%, whereas the patency rates for those not taking statins were 55%, 45%, and 36% at 12, 24, and 36 months, respectively (P ¼ .179). Statins had no significant influence on patency rates when lesions were stratified for severity (TASC A/B, P ¼ .162; C/D, P ¼ .638). There was no significant difference in those treated for claudication or critical limb ischemia (P ¼ .929). Statin compliance was found to be 86% at a mean follow-up of 23.6 months. Conclusions: Whereas the use of statins has been shown to reduce cardiovascular morbidity and mortality in patients with peripheral vascular disease, the ability of these drugs to improve primary patency rates of patients after superficial femoral and popliteal artery stenting remains speculative. Vascular Surgery: An Essential Hospital Resource in Modern Health Care Miguel F. Manzur, MD, Sung W. Ham, MD, Ramsey S. Elsayed, MD, Trevor Simcox, BS, Fred A. Weaver, MD, MMM. Keck School of Medicine of USC, Los Angeles, Calif Objective: Vascular surgeons are consulted by other surgical specialties for intraoperative vascular exposure, reconstruction, or hemorrhage control. These requests occur both electively and emergently. We analyzed the value of vascular surgery operative services as a resource to other surgical specialties at our institution. Methods: Intraoperative elective and emergent vascular surgery consultations requiring operative intervention were reviewed during a 3-year period (2013-2016). Patient demographics, requesting surgical specialty, indication for and type of vascular operative intervention, and work relative value units generated for the intervention were recorded. Results: Seventy-six patients required vascular surgery intraoperative consultations for operative intervention. Operative interventions were emergent in 57% and elective in 43%. The most common elective intervention was oncologic vascular reconstruction; the most common emergency intervention was hemorrhage control during oncologic resection. Vascular beds included the lower extremity (35%), aorta and its major branches (33%), inferior vena cava and major venous structures (19%), vessels of the head and neck (7%), and upper extremity (6%). Requesting surgical specialties were cardiac (24%), urology (18%), orthopedics (17%), hepatobiliary/transplantation (16%), and others (25%). Reasons for consultation were vascular reconstruction (30%), dissection requiring vascular exposure (21%), hemorrhage control (20%), acute limb ischemia (15%), and access difficulties (14%). The types of repairs were primary vessel repair (32%), interposition grafts (28%), bypass (21%), and others (19%). Ninety-nine percent (75/76) of cases were completed after vascular assistance. In-hospital mortality was 10.5%
Abstracts 543
(8/76), none related to vascular intervention. Mean work relative value units generated per vascular surgery intervention were 22.3. Conclusions: The availability of vascular surgeons ensures the successful completion of technically challenging operations performed by other surgical specialties. Furthermore, intraoperative vascular surgery services are frequent in both elective and emergent settings and involve a variety of vascular beds. Vascular surgery is an essential hospital resource in the modern health care environment. Intraluminal Thrombus Is Associated With Aortic Wall Weakening in Small Ruptured Abdominal Aortic Aneurysms Jeffrey D. Crawford, MD, Stephen J. Haller, BS, Gregory J. Landry, MD, Cherrie Abraham, MD, Gregory L. Moneta, MD, Sandra Rugonyi, PhD, Amir F. Azarbal, MD. Oregon Health and Sciences University, Portland, Ore Objectives: Intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) has been shown to provide a biomechanical advantage by decreasing peak wall stress (PWS) while also acting as a nidus of inflammation and resultant aortic wall degeneration. In this study, we sought to explore the association between ILT and the risk of AAA rupture in small, high-risk aneurysms. Methods: Patients treated at our institution from 2001 to 2014 for ruptured AAA (rAAA) were retrospectively identified. Patients with small rAAA (<60 mm) with high-resolution computed tomography angiography available for study were included. These patients were considered to have high-risk aneurysms, given that they ruptured at relatively small AAA diameters. For comparison, a low-risk cohort of patients with large non-rAAA ($60 mm) with high-resolution preoperative computed tomography angiography were sequentially identified. Three-dimensional AAA anatomy was digitally reconstructed for each patient, and ILT percentage volume was computed (ILT percentage volume ¼ (volume ILT/[volume ILT + volume lumen]) 100). Finite element analysis was then performed to calculate AAA mean wall stress (MWS) and PWS distributions for each patient. Results: Patient demographics and results are summarized in Table. Patients with small rAAA had greater ILT percentage volume compared with patients with large non-rAAA (69 6 12% vs 57 6 12%; P ¼ .02) (Fig, A). Patients with small rAAA had lower MWS (47 6 17 kPa vs 72 6 19 kPa; P ¼ .003) and PWS (119 6 40 kPa vs 237 6 96 kPa; P < .001) compared with patients with large non-rAAA (Fig, B). Increased ILT percentage volume was associated with both decreased MWS and decreased PWS (Fig, C and D). Conclusions: Although increased ILT percentage volume is associated with lower MWS and PWS, it is also associated with rAAA at smaller diameters. Therefore, the protective biomechanical advantage of ILT in lowering PWS seems to be outweighed by weakening of the aortic wall in patients with small rAAA. Increased ILT percentage volume may be a surrogate marker for decreased aortic wall strength and a marker of high-risk AAAs.
Table. Patient demographics and results summary
AAA diameter, mm Age, years Male Hypertension Smoker ILT volume, mL ILT percentage volume, % Mean ILT thickness, mm MWS, kPa PWS, kPa
Large non-rAAA (n ¼ 15)
Small rAAA (n ¼ 9)
P
68.1 6 11.9 70.8 6 9.7 13 (86.7) 9 (60.0) 15 (100.0) 161 6 79 56.7 6 11.6 8.1 6 2.3 72 6 19 273 6 96
52.1 6 7.6 67.9 6 5.7 6 (66.7) 8 (88.9) 9 (100.0) 92 6 32 68.8 6 11.6 8.4 6 2.3 47 6 17 119 6 40
.002 NS NS NS NS .007 .022 NS .003 <.001
AAA, Abdominal aortic aneurysm; ILT, intraluminal thrombus; MWS, mean wall stress; NS, not significant; PWS, peak wall stress; rAAA, ruptured AAA. Continuous variables are presented as mean 6 standard deviation and categorical variables are presented as number (%).