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Papers by Gary Lemmon

Journal of Vascular Surgery

OBJECTIVE The optimal revascularization modality following complete resection of aortic graft inf... more OBJECTIVE The optimal revascularization modality following complete resection of aortic graft infection (AGI) without enteric involvement remains unclear. The purpose of this investigation is to determine the revascularization approach associated with the lowest morbidity and mortality using real-world data in patients undergoing complete excision of AGI. METHODS A retrospective, multi-institutional study of AGI from 2002-2014 was performed using a standardized database. Baseline demographics, comorbidities, and perioperative variables were recorded. The primary outcome was infection-free survival. Descriptive statistics, Kaplan-Meier survival analysis, and univariate and multivariable analyses were performed. RESULTS 241 patients at 34 institutions from 7 countries presented with AGI during the study period (median age 68 years; 75% male). The initial aortic procedures that resulted in AGI were 172 surgical grafts (71%) and 66 endografts (27%) and 3 unknown (2%). 172 (71%) of the patients underwent complete excision of infected aortic graft material followed by in situ (in-line) bypass (ISB), including antibiotic-treated prosthetic graft (35%), autogenous femoral vein (NAIS) (24%), and cryopreserved allograft (41%). 69 patients (29%) underwent extra-anatomic bypass (EAB). Overall median Kaplan-Meier (KM) estimated survival was 5.8 years. Perioperative mortality was 16%. When stratified by ISB versus EAB, there was a significant difference in KM estimated infection-free survival (2910 days, IQR 391, 3771 versus 180 days, IQR 27, 3750 days; p<0.001). There were otherwise no significant differences in presentation, comorbidities, nor perioperative variables. Multivariable Cox regression showed lower infection-free survival among patients with EAB (HR 2.4, 95% CI 1.6-3.6; p<0.001), polymicrobial infection (HR 2.2, 95% CI 1.4-3.5; p=0.001), MRSA infection (HR 1.7, 95% CI 1.1-2.7; p=0.02), as well as the protective effect of omental/muscle flap coverage (HR 0.59, 95% CI 0.37-0.92; p=0.02). CONCLUSIONS After complete resection of AGI, perioperative mortality is 16% and median overall survival is 5.8 years. EAB is associated with nearly a two-and-half fold higher re-infection/mortality compared to ISB. Omental and/or muscle flap coverage of the repair appear protective.

Journal of Vascular Surgery, 2021

Seminars in Vascular Surgery, 2021

COVID-19 infection show inferior outcomes (morbidity) and increased mortality. Diseasespecific va... more COVID-19 infection show inferior outcomes (morbidity) and increased mortality. Diseasespecific vascular surgery study collaboratives about COVID-19 were created for the desire to study the disease in a more focused manner than possible through registry outcomes. This review describes the pandemic effect on multiple VASCUNET registries including Germany (GermanVasc), Sweden (SwedVasc), United Kingdom (UK National Vascular Registry), Australia and New Zealand (bi-national Australasian Vascular Audit), as well as the United States (Society for Vascular Surgery Vascular Quality Initiative). We will highlight the continued collaboration of VASCUNET with the Vascular Quality Initiative in the International Consortium of Vascular Registries as part of the Medical Device Epidemiology Network coordinated registry network. Vascular registries must remain flexible and responsive to new and future real-world problems affecting vascular patients.

Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2021

Retrospective review of VQI venous registry volume between 1 st Quarter of 2019 and 2020. Key Fin... more Retrospective review of VQI venous registry volume between 1 st Quarter of 2019 and 2020. Key Findings: Seventy four percent of respondents adopted a restrictive pandemic operating policy to urgent In response to the pandemic, an abrupt pivot of VQI physician members away from standard clinical practice to a restrictive phase of emergent and urgent vascular procedures occurred. The Society for Vascular Surgery Patient Safety Organization queried both data managers and physicians in May 2020. Approximately three fourths (74%) of physicians adopted restrictive operating policies for urgent and emergent cases only, while one half proceeded with 'time sensitive' elective cases as urgent. Data manager case entry was negatively affected by both low case volumes and staffing due to re-assignment or furlough. Venous registry volumes were reduced five-fold in 1 st Quarter of 2020 compared to a similar period in 2019. The consequences of delaying vascular procedures for ambulatory venous practice remain unknown with increased morbidity likely. Challenges to determine venous thromboembolism mortality impact exist given difficulty in verifying 'in home and extended care facility' deaths. Further ramifications of a pandemic shutdown will likely be amplified if postponement of elective vascular care extends beyond a short window of time. It will be important to monitor disease progression and case severity as a result of policy shifts adopted locally in response to pandemic surges.

Annals of Vascular Surgery, 2021

INTRODUCTION Aortic graft infection remains a considerable clinical challenge, and it is unclear ... more INTRODUCTION Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection. METHODS A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002-2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed. RESULTS One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%.The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (p=0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; p=0.01) as well as aortoenteric fistula (HR 1.9, p=0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, p=0.04), as well as those with American Society of Anesthesiologists (ASA) classification less than 3 (HR 0.35, p=0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs 60 years, p=0.01) and less likely to have patent repairs during follow up (59% vs. 32%, p=0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs 29%, p<0.01) CONCLUSIONS: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material.

Vessel Plus, 2018

We present a case of an aorto-enteric fistula (AEF) with chronic, persistent bleeding from a blin... more We present a case of an aorto-enteric fistula (AEF) with chronic, persistent bleeding from a blind aortic stump managed by endovascular means. This novel approach may have extended the life of a patient who would otherwise have been subject to a high perioperative morbidity or persistent bleeding and death. While our patient ultimately expired, we believe this technique can be considered for temporization in highly-selected patients.

Annals of Vascular Surgery, 2018

EVAR. However, in 42.5% of EVAR and 32.8% of OAAR patients, the diameter of the AAA was 5.4 cm or... more EVAR. However, in 42.5% of EVAR and 32.8% of OAAR patients, the diameter of the AAA was 5.4 cm or less at the time of the repair. Compared to patients older than 70, younger patients were more likely to have a small AAA repaired (OR¼1.52, 95%CI¼1.27-1.81). Additionally, patients who underwent EVAR were more likely to have a small AAA repaired compared to the OAAR cohort (OR¼1.62, 95%CI¼1.20-2.22). Regardless of AAA size at the time of repair, there were no differences in perioperative morbidity and mortality between groups (Table 1). Conclusions: There were no differences in perioperative outcomes after AAA repair independent of the aneurysm diameter. We found a high rate of repair of asymptomatic AAA in men with a diameter less 5.5 cm. This was more common in young patients and those undergoing EVAR versus OAAR.

Journal of Vascular Surgery, 2018

Journal of Vascular Surgery, 2019

Objective: The optimal revascularization modality in secondary abdominal aortoenteric fistula (SA... more Objective: The optimal revascularization modality in secondary abdominal aortoenteric fistula (SAEF) is debated, although in situ bypass (ISB) has increasingly been used. Therefore, we aimed to quantify the association between extra-anatomic bypass (EAB) and ISB mortality in SAEF. Methods: A retrospective, multi-institutional study of SAEF from 2002 to 2014 was performed. Baseline demographics and comorbidities and procedural, operative, and postoperative variables were recorded, with the primary outcome being mortality at last follow-up. Results: There were 223 patients at 31 institutions who presented with SAEF (median age, 72 years; 77% male), which was treated with 171 bypass grafts and 48 endografts. Of these, 101 (45%) were managed with ISB: 48 antibiotic soaked, 17 autogenous femoral vein (neoaortoiliac system), 31 cryopreserved allografts, and 5 untreated prosthetic grafts; 70 (31%) underwent EAB with infected graft excision. The remainder underwent endografts (10 [5%]), partial replacements (33 [15%]), or medicalonly management (4 [2%]). Comparing EAB vs ISB, EAB patients were older (73 vs 69 years; P < .01), more frequently infected with streptococcus (63% vs. 37%; P ¼ .02), and more frequently treated with fluoroquinolones (83% vs 17%; P < .01), and they endured less operative hemorrhage (1200 mL vs. 4000 mL; P < .01). There were otherwise no significant differences in presentation, comorbidities, and intraoperative or postoperative variables. Overall median Kaplan-Meier estimated survival was 270 days. When stratified by EAB vs ISB, there was no significant difference in Kaplan-Meier estimated survival (P ¼ .85; Fig). Multivariable Cox regression showed that the duration of antibiotic use (hazard ratio, 0.98; 95% confidence interval, 0.96-0.99; P < .01) and omental wrapping (hazard ratio, 0.52; 95% confidence interval, 0.33-0.81; P < 0.01) independently decreased mortality. Conclusions: In this largest reported cohort of SAEF, <50% of patients survived for 9 months after presentation. ISB does not offer a survival advantage compared with EAB. Each week of antibiotic use decreases mortality by 2%, whereas omental wrapping decreases mortality by 48%. Prospective multicenter registry data can provide additional data to improve survival in patients with SAEF.

Journal of Vascular Surgery Cases, Innovations and Techniques, 2019

Type IIIB endoleaks resulting from endograft fabric tear are an uncommon but serious late complic... more Type IIIB endoleaks resulting from endograft fabric tear are an uncommon but serious late complication of endovascular aortic aneurysm repair. The Strata fabric used in the earlier generation AFX endograft (updated to Duraply in October 2014) has been associated with an increased frequency of these events. Herein we report on two patients exhibiting delayed type IIIB endoleaks after AFX device insertion to treat an abdominal aortic aneurysm and discuss optimal relining techniques.

Annals of Vascular Surgery, 2019

Junctional separation and resulting type IIIa endoleak is a well-known problem after EVAR (endova... more Junctional separation and resulting type IIIa endoleak is a well-known problem after EVAR (endovascular aneurysm repair). This complication results in sac pressurization, enlargement, and eventual rupture. In this manuscript, we review the incidence of this late finding in our experience with the Cook Zenith Fenestrated endoprosthesis (ZFEN, Bloomington, IN) Methods: A retrospective review was performed of a prospectively maintained institutional ZFEN FEVAR (fenestrated EVAR) database capturing all ZFENs implanted at a large-volume, academic hospital system. Patients who experienced junctional separation between the fenestrated main body and distal bifurcated graft (with or without type IIIa endoleak) at any time after initial endoprosthesis implantation were subject to further evaluation of imaging and medical records to abstract clinical courses. Results: In 110 ZFENs implanted from October 2012 to December 2017 followed for a mean of 1.5 years, we observed a 4.5% and 2.7% incidence of clinically significant junctional separation and type IIIa endoleak, respectively. Junctional separation was directly related to concurrent type Ib endoleak in all five patients. Three patients presented with sac enlargement. One patient did not demonstrate any evidence of clinically significant endoleak and had a decreasing sac size during follow-up imaging. The mean time to diagnosis of modular separation in these patients was 40 months. Junctional separation was captured in surveillance in two patients and reintervened upon before manifestation of endoleak. However, the remaining three patients completed modular separation resulting in rupture and emergent intervention in two and an aortic-related mortality in the other. Conclusions: Junctional separation between the fenestrated main and distal bifurcated body with the potential for type IIIa endoleak is an established complication associated with the ZFEN platform. Therefore, we advocate for maximizing aortic overlap during the index procedure followed by aggressive surveillance and treatment of stent overlap loss captured on imaging.

Journal of Vascular Surgery, 2018

High energy density and rapid reactivity are the future trend for nano-energetic materials. Energ... more High energy density and rapid reactivity are the future trend for nano-energetic materials. Energetic performance of nano-energetic materials depends on the interfacial diffusion and mass transfer during the reacted process. However, the development of desired structure to significantly enhance reactivity still remains challenging. Here we focused on the design and preparation of 3D porous hollow Co 3 O 4 micro-spheres, in which gas-blowing agents (air) and maximize interfacial interactions were introduced to enhance mass transport and reduce the diffusion distance between the oxidizer and fuel (Aluminum). The 3D hierarchical Co 3 O 4 /Al based nano-energetic materials show a low-onset decomposition temperature (423°C), and high heat output (3118 J g À1) resulting from porous and hollow nano-structure of Co 3 O 4 micro-spheres. Furthermore, 3D hierarchical Co 3 O 4 /Al arrays were directly fabricated on the silicon substrate, which was fully compatible with silicon-based microelectromechanical systems to achieve functional nanoenergetics-on-a-chip. This approach provides a simple and efficient way to fabricate 3D ordered nano-energetic arrays with superior reactivity and the potential on the application in microenergetic devices.

Journal of vascular surgery, Jan 3, 2018

The purpose of this investigation was to determine our limb-related contemporary pediatric revasc... more The purpose of this investigation was to determine our limb-related contemporary pediatric revascularization perioperative and follow-up outcomes after major blunt and penetrating trauma. A retrospective review was performed of a prospectively maintained pediatric trauma database spanning January 2010 to December 2017 to capture all level I trauma activations that resulted in a peripheral arterial revascularization procedure. All preoperative, intraoperative, and postoperative continuous variables are reported as a mean ± standard deviation; categorical variables are reported as a percentage of the population of interest. During the study period, 1399 level I trauma activations occurred at a large-volume, urban children's hospital. The vascular surgery service was consulted in 2.6% (n = 36) of these cases for suspected vascular injury based on imaging or physical examination. Our study population included only patients who received an arterial revascularization, which was perfor...

Journal of vascular surgery, Jan 6, 2018

This investigation describes the perioperative and early follow-up results associated with transc... more This investigation describes the perioperative and early follow-up results associated with transcarotid artery revascularization (TCAR) in patients not participating in the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure II (ROADSTER-2) registry using the ENROUTE neuroprotection system (ENPS; Silk Road Medical, Sunnyvale, Calif). A retrospective review was performed capturing all TCAR/ENPS procedures in patients deemed to be at high risk for complications after traditional carotid endarterectomy. All patients enrolled in the ROADSTER-2 registry were excluded, leaving only those treated outside trial regulations for analysis. Preoperative demographics, intraoperative variables, and perioperative and follow-up outcomes were abstracted and reported herein. From December 2015 to January 2018, there were 75 carotid arteries treated at our institution. All interventions were performed on carotid arteries that were symptomatic with ≥50% stenosis (46...

Journal of vascular surgery, Oct 18, 2018

Proximal neck dilation is a serious long-term complication directly causing the failure of endova... more Proximal neck dilation is a serious long-term complication directly causing the failure of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) of abdominal aortic aneurysms. However, the implantation of a fenestrated device presents the opportunity for proximal extension of the aortic reconstruction into a healthy segment while maintaining patency of the visceral vessels. The objective of this investigation was to report perioperative and follow-up outcomes using the Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent system in salvaging previous aortic repairs undergoing type IA endoleak or aneurysmal degeneration of the proximal neck. We performed a retrospective review of a prospectively maintained institutional database capturing all fenestrated EVAR (FEVAR) cases with the ZFEN platform. Fenestrated cases were classified as primary FEVAR or reoperative FEVAR (rFEVAR) after previous EVAR or OSR. Cohort comparisons were performed using Fisher exac...

Journal of vascular surgery cases and innovative techniques, 2017

Large-vessel chronic traumatic arteriovenous fistulas are a rare complication after trauma. Delay... more Large-vessel chronic traumatic arteriovenous fistulas are a rare complication after trauma. Delayed presentation can consist of one or more features of high-output cardiac failure, pulsatile abdominal mass, bruit, limb ischemia, and venous congestion. We describe a patient with a complex iliocaval fistula secondary to a remote gunshot wound associated with a large 8.5-cm aortic aneurysm. Informed consent of the patient was obtained for publication of the case.

Annals of vascular surgery, Jan 5, 2018

Single-length saphenous vein continues to be the conduit of choice in infected-field critical lim... more Single-length saphenous vein continues to be the conduit of choice in infected-field critical limb ischemia. However, half of these individuals have inadequate vein secondary to previous use or chronic venous disease. We reviewed our outcomes of infected-field infrainguinal bypasses performed with cryopreserved homografts (CHs), a widely accepted alternative to autogenous vein in this setting. This is a retrospective, institutional descriptive analysis of infected-field infrainguinal revascularizations between 2012 and 2015. Twenty-four operations were performed in the same number of patients for limb ischemia with signs of active infection. The mean age of the cohort examined was 62.5 ± 14.4 (standard deviation) years. Mean Society of Vascular Surgery risk score was 3.9 with a baseline Rutherford's chronic ischemia score of 4.3 at presentation. Emergent procedures constituted 29% of cases, and the remainder cases were urgent procedures. The CH bypass captured was a reoperative ...

Annals of vascular surgery, Jan 22, 2018

The accepted treatment for acute limb ischemia (ALI) is immediate systemic anticoagulation and ti... more The accepted treatment for acute limb ischemia (ALI) is immediate systemic anticoagulation and timely reperfusion to restore blood flow. In this study, we describe the retrospective assessment of pretransfer management decisions by referring hospitals to an academic tertiary care facility and its impact on perioperative adverse events. A retrospective analysis of ALI patients transferred to us via our Level I Vascular Emergency program from 2010 to 2013 was performed. Patient demographics, comorbidities, Rutherford ischemia classification, time to anticoagulation, and time to reperfusion were tabulated and analyzed for correlation to incidence of major adverse limb events (MALE), mortality, and bypass patency in the perioperative period (30-day postoperative). All time intervals were calculated from the onset of symptoms and categorized into three subcohorts (<6 hrs, 6-48 hrs, and >48 hrs). Eighty-seven patients with an average age of 64.0 (± 16.2) years presented to outlying ...

Journal of vascular surgery, Aug 27, 2018

The Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent graft system was appro... more The Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent graft system was approved for commercial use by the Food and Drug Administration in April 2012. We report our single-center experience of 100 consecutive patients treated with the ZFEN platform from October 2012 to March 2017. A retrospective review of our prospectively maintained fenestrated endovascular aneurysm repair (FEVAR) database at a tertiary care academic institution located in the Midwest United States was performed for descriptive analysis. All continuous variables are reported as a mean ± standard deviation and compared using two-sided Student t-tests. Categorical variables were compared using two-sided Fisher exact tests. All but one of the procedures were elective in nature. Overall intraoperative characteristics included a mean blood loss (estimated blood loss) of 388 ± 385 mL, fluoroscopy time of 63 ± 30 minutes, radiation dose of 437 ± 272 rad, contrast material volume of 99 ± 36 mL, and ope...

Journal of vascular surgery, May 7, 2017

Acute limb ischemia (ALI) in infants poses a challenge to the clinician secondary to poor operati... more Acute limb ischemia (ALI) in infants poses a challenge to the clinician secondary to poor operative outcomes, limb loss risk, and lifelong morbidity. This retrospective study reviewed a 10-year institutional experience with the nonoperative management of ALI in infants. Infants (aged ≤12 months) diagnosed with ALI by duplex ultrasound and treated with initial nonoperative management at a tertiary care children's hospital were identified through vascular laboratory arterial duplex ultrasound records and International Classification of Diseases and Current Procedural Terminology codes associated with ALI. Demographics of the patients, injury characteristics, treatment administered, and outcomes were abstracted by chart review and presented using descriptive statistics. During the study period, a total of 25 (28% female) infant patients were diagnosed with ALI. The average age for this cohort was 3.5 ± 3.2 months (standard deviation). Most cases were secondary to iatrogenic injury ...

Journal of Vascular Surgery

OBJECTIVE The optimal revascularization modality following complete resection of aortic graft inf... more OBJECTIVE The optimal revascularization modality following complete resection of aortic graft infection (AGI) without enteric involvement remains unclear. The purpose of this investigation is to determine the revascularization approach associated with the lowest morbidity and mortality using real-world data in patients undergoing complete excision of AGI. METHODS A retrospective, multi-institutional study of AGI from 2002-2014 was performed using a standardized database. Baseline demographics, comorbidities, and perioperative variables were recorded. The primary outcome was infection-free survival. Descriptive statistics, Kaplan-Meier survival analysis, and univariate and multivariable analyses were performed. RESULTS 241 patients at 34 institutions from 7 countries presented with AGI during the study period (median age 68 years; 75% male). The initial aortic procedures that resulted in AGI were 172 surgical grafts (71%) and 66 endografts (27%) and 3 unknown (2%). 172 (71%) of the patients underwent complete excision of infected aortic graft material followed by in situ (in-line) bypass (ISB), including antibiotic-treated prosthetic graft (35%), autogenous femoral vein (NAIS) (24%), and cryopreserved allograft (41%). 69 patients (29%) underwent extra-anatomic bypass (EAB). Overall median Kaplan-Meier (KM) estimated survival was 5.8 years. Perioperative mortality was 16%. When stratified by ISB versus EAB, there was a significant difference in KM estimated infection-free survival (2910 days, IQR 391, 3771 versus 180 days, IQR 27, 3750 days; p<0.001). There were otherwise no significant differences in presentation, comorbidities, nor perioperative variables. Multivariable Cox regression showed lower infection-free survival among patients with EAB (HR 2.4, 95% CI 1.6-3.6; p<0.001), polymicrobial infection (HR 2.2, 95% CI 1.4-3.5; p=0.001), MRSA infection (HR 1.7, 95% CI 1.1-2.7; p=0.02), as well as the protective effect of omental/muscle flap coverage (HR 0.59, 95% CI 0.37-0.92; p=0.02). CONCLUSIONS After complete resection of AGI, perioperative mortality is 16% and median overall survival is 5.8 years. EAB is associated with nearly a two-and-half fold higher re-infection/mortality compared to ISB. Omental and/or muscle flap coverage of the repair appear protective.

Journal of Vascular Surgery, 2021

Seminars in Vascular Surgery, 2021

COVID-19 infection show inferior outcomes (morbidity) and increased mortality. Diseasespecific va... more COVID-19 infection show inferior outcomes (morbidity) and increased mortality. Diseasespecific vascular surgery study collaboratives about COVID-19 were created for the desire to study the disease in a more focused manner than possible through registry outcomes. This review describes the pandemic effect on multiple VASCUNET registries including Germany (GermanVasc), Sweden (SwedVasc), United Kingdom (UK National Vascular Registry), Australia and New Zealand (bi-national Australasian Vascular Audit), as well as the United States (Society for Vascular Surgery Vascular Quality Initiative). We will highlight the continued collaboration of VASCUNET with the Vascular Quality Initiative in the International Consortium of Vascular Registries as part of the Medical Device Epidemiology Network coordinated registry network. Vascular registries must remain flexible and responsive to new and future real-world problems affecting vascular patients.

Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2021

Retrospective review of VQI venous registry volume between 1 st Quarter of 2019 and 2020. Key Fin... more Retrospective review of VQI venous registry volume between 1 st Quarter of 2019 and 2020. Key Findings: Seventy four percent of respondents adopted a restrictive pandemic operating policy to urgent In response to the pandemic, an abrupt pivot of VQI physician members away from standard clinical practice to a restrictive phase of emergent and urgent vascular procedures occurred. The Society for Vascular Surgery Patient Safety Organization queried both data managers and physicians in May 2020. Approximately three fourths (74%) of physicians adopted restrictive operating policies for urgent and emergent cases only, while one half proceeded with 'time sensitive' elective cases as urgent. Data manager case entry was negatively affected by both low case volumes and staffing due to re-assignment or furlough. Venous registry volumes were reduced five-fold in 1 st Quarter of 2020 compared to a similar period in 2019. The consequences of delaying vascular procedures for ambulatory venous practice remain unknown with increased morbidity likely. Challenges to determine venous thromboembolism mortality impact exist given difficulty in verifying 'in home and extended care facility' deaths. Further ramifications of a pandemic shutdown will likely be amplified if postponement of elective vascular care extends beyond a short window of time. It will be important to monitor disease progression and case severity as a result of policy shifts adopted locally in response to pandemic surges.

Annals of Vascular Surgery, 2021

INTRODUCTION Aortic graft infection remains a considerable clinical challenge, and it is unclear ... more INTRODUCTION Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection. METHODS A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002-2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed. RESULTS One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%.The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (p=0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; p=0.01) as well as aortoenteric fistula (HR 1.9, p=0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, p=0.04), as well as those with American Society of Anesthesiologists (ASA) classification less than 3 (HR 0.35, p=0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs 60 years, p=0.01) and less likely to have patent repairs during follow up (59% vs. 32%, p=0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs 29%, p<0.01) CONCLUSIONS: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material.

Vessel Plus, 2018

We present a case of an aorto-enteric fistula (AEF) with chronic, persistent bleeding from a blin... more We present a case of an aorto-enteric fistula (AEF) with chronic, persistent bleeding from a blind aortic stump managed by endovascular means. This novel approach may have extended the life of a patient who would otherwise have been subject to a high perioperative morbidity or persistent bleeding and death. While our patient ultimately expired, we believe this technique can be considered for temporization in highly-selected patients.

Annals of Vascular Surgery, 2018

EVAR. However, in 42.5% of EVAR and 32.8% of OAAR patients, the diameter of the AAA was 5.4 cm or... more EVAR. However, in 42.5% of EVAR and 32.8% of OAAR patients, the diameter of the AAA was 5.4 cm or less at the time of the repair. Compared to patients older than 70, younger patients were more likely to have a small AAA repaired (OR¼1.52, 95%CI¼1.27-1.81). Additionally, patients who underwent EVAR were more likely to have a small AAA repaired compared to the OAAR cohort (OR¼1.62, 95%CI¼1.20-2.22). Regardless of AAA size at the time of repair, there were no differences in perioperative morbidity and mortality between groups (Table 1). Conclusions: There were no differences in perioperative outcomes after AAA repair independent of the aneurysm diameter. We found a high rate of repair of asymptomatic AAA in men with a diameter less 5.5 cm. This was more common in young patients and those undergoing EVAR versus OAAR.

Journal of Vascular Surgery, 2018

Journal of Vascular Surgery, 2019

Objective: The optimal revascularization modality in secondary abdominal aortoenteric fistula (SA... more Objective: The optimal revascularization modality in secondary abdominal aortoenteric fistula (SAEF) is debated, although in situ bypass (ISB) has increasingly been used. Therefore, we aimed to quantify the association between extra-anatomic bypass (EAB) and ISB mortality in SAEF. Methods: A retrospective, multi-institutional study of SAEF from 2002 to 2014 was performed. Baseline demographics and comorbidities and procedural, operative, and postoperative variables were recorded, with the primary outcome being mortality at last follow-up. Results: There were 223 patients at 31 institutions who presented with SAEF (median age, 72 years; 77% male), which was treated with 171 bypass grafts and 48 endografts. Of these, 101 (45%) were managed with ISB: 48 antibiotic soaked, 17 autogenous femoral vein (neoaortoiliac system), 31 cryopreserved allografts, and 5 untreated prosthetic grafts; 70 (31%) underwent EAB with infected graft excision. The remainder underwent endografts (10 [5%]), partial replacements (33 [15%]), or medicalonly management (4 [2%]). Comparing EAB vs ISB, EAB patients were older (73 vs 69 years; P < .01), more frequently infected with streptococcus (63% vs. 37%; P ¼ .02), and more frequently treated with fluoroquinolones (83% vs 17%; P < .01), and they endured less operative hemorrhage (1200 mL vs. 4000 mL; P < .01). There were otherwise no significant differences in presentation, comorbidities, and intraoperative or postoperative variables. Overall median Kaplan-Meier estimated survival was 270 days. When stratified by EAB vs ISB, there was no significant difference in Kaplan-Meier estimated survival (P ¼ .85; Fig). Multivariable Cox regression showed that the duration of antibiotic use (hazard ratio, 0.98; 95% confidence interval, 0.96-0.99; P < .01) and omental wrapping (hazard ratio, 0.52; 95% confidence interval, 0.33-0.81; P < 0.01) independently decreased mortality. Conclusions: In this largest reported cohort of SAEF, <50% of patients survived for 9 months after presentation. ISB does not offer a survival advantage compared with EAB. Each week of antibiotic use decreases mortality by 2%, whereas omental wrapping decreases mortality by 48%. Prospective multicenter registry data can provide additional data to improve survival in patients with SAEF.

Journal of Vascular Surgery Cases, Innovations and Techniques, 2019

Type IIIB endoleaks resulting from endograft fabric tear are an uncommon but serious late complic... more Type IIIB endoleaks resulting from endograft fabric tear are an uncommon but serious late complication of endovascular aortic aneurysm repair. The Strata fabric used in the earlier generation AFX endograft (updated to Duraply in October 2014) has been associated with an increased frequency of these events. Herein we report on two patients exhibiting delayed type IIIB endoleaks after AFX device insertion to treat an abdominal aortic aneurysm and discuss optimal relining techniques.

Annals of Vascular Surgery, 2019

Junctional separation and resulting type IIIa endoleak is a well-known problem after EVAR (endova... more Junctional separation and resulting type IIIa endoleak is a well-known problem after EVAR (endovascular aneurysm repair). This complication results in sac pressurization, enlargement, and eventual rupture. In this manuscript, we review the incidence of this late finding in our experience with the Cook Zenith Fenestrated endoprosthesis (ZFEN, Bloomington, IN) Methods: A retrospective review was performed of a prospectively maintained institutional ZFEN FEVAR (fenestrated EVAR) database capturing all ZFENs implanted at a large-volume, academic hospital system. Patients who experienced junctional separation between the fenestrated main body and distal bifurcated graft (with or without type IIIa endoleak) at any time after initial endoprosthesis implantation were subject to further evaluation of imaging and medical records to abstract clinical courses. Results: In 110 ZFENs implanted from October 2012 to December 2017 followed for a mean of 1.5 years, we observed a 4.5% and 2.7% incidence of clinically significant junctional separation and type IIIa endoleak, respectively. Junctional separation was directly related to concurrent type Ib endoleak in all five patients. Three patients presented with sac enlargement. One patient did not demonstrate any evidence of clinically significant endoleak and had a decreasing sac size during follow-up imaging. The mean time to diagnosis of modular separation in these patients was 40 months. Junctional separation was captured in surveillance in two patients and reintervened upon before manifestation of endoleak. However, the remaining three patients completed modular separation resulting in rupture and emergent intervention in two and an aortic-related mortality in the other. Conclusions: Junctional separation between the fenestrated main and distal bifurcated body with the potential for type IIIa endoleak is an established complication associated with the ZFEN platform. Therefore, we advocate for maximizing aortic overlap during the index procedure followed by aggressive surveillance and treatment of stent overlap loss captured on imaging.

Journal of Vascular Surgery, 2018

High energy density and rapid reactivity are the future trend for nano-energetic materials. Energ... more High energy density and rapid reactivity are the future trend for nano-energetic materials. Energetic performance of nano-energetic materials depends on the interfacial diffusion and mass transfer during the reacted process. However, the development of desired structure to significantly enhance reactivity still remains challenging. Here we focused on the design and preparation of 3D porous hollow Co 3 O 4 micro-spheres, in which gas-blowing agents (air) and maximize interfacial interactions were introduced to enhance mass transport and reduce the diffusion distance between the oxidizer and fuel (Aluminum). The 3D hierarchical Co 3 O 4 /Al based nano-energetic materials show a low-onset decomposition temperature (423°C), and high heat output (3118 J g À1) resulting from porous and hollow nano-structure of Co 3 O 4 micro-spheres. Furthermore, 3D hierarchical Co 3 O 4 /Al arrays were directly fabricated on the silicon substrate, which was fully compatible with silicon-based microelectromechanical systems to achieve functional nanoenergetics-on-a-chip. This approach provides a simple and efficient way to fabricate 3D ordered nano-energetic arrays with superior reactivity and the potential on the application in microenergetic devices.

Journal of vascular surgery, Jan 3, 2018

The purpose of this investigation was to determine our limb-related contemporary pediatric revasc... more The purpose of this investigation was to determine our limb-related contemporary pediatric revascularization perioperative and follow-up outcomes after major blunt and penetrating trauma. A retrospective review was performed of a prospectively maintained pediatric trauma database spanning January 2010 to December 2017 to capture all level I trauma activations that resulted in a peripheral arterial revascularization procedure. All preoperative, intraoperative, and postoperative continuous variables are reported as a mean ± standard deviation; categorical variables are reported as a percentage of the population of interest. During the study period, 1399 level I trauma activations occurred at a large-volume, urban children's hospital. The vascular surgery service was consulted in 2.6% (n = 36) of these cases for suspected vascular injury based on imaging or physical examination. Our study population included only patients who received an arterial revascularization, which was perfor...

Journal of vascular surgery, Jan 6, 2018

This investigation describes the perioperative and early follow-up results associated with transc... more This investigation describes the perioperative and early follow-up results associated with transcarotid artery revascularization (TCAR) in patients not participating in the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure II (ROADSTER-2) registry using the ENROUTE neuroprotection system (ENPS; Silk Road Medical, Sunnyvale, Calif). A retrospective review was performed capturing all TCAR/ENPS procedures in patients deemed to be at high risk for complications after traditional carotid endarterectomy. All patients enrolled in the ROADSTER-2 registry were excluded, leaving only those treated outside trial regulations for analysis. Preoperative demographics, intraoperative variables, and perioperative and follow-up outcomes were abstracted and reported herein. From December 2015 to January 2018, there were 75 carotid arteries treated at our institution. All interventions were performed on carotid arteries that were symptomatic with ≥50% stenosis (46...

Journal of vascular surgery, Oct 18, 2018

Proximal neck dilation is a serious long-term complication directly causing the failure of endova... more Proximal neck dilation is a serious long-term complication directly causing the failure of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) of abdominal aortic aneurysms. However, the implantation of a fenestrated device presents the opportunity for proximal extension of the aortic reconstruction into a healthy segment while maintaining patency of the visceral vessels. The objective of this investigation was to report perioperative and follow-up outcomes using the Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent system in salvaging previous aortic repairs undergoing type IA endoleak or aneurysmal degeneration of the proximal neck. We performed a retrospective review of a prospectively maintained institutional database capturing all fenestrated EVAR (FEVAR) cases with the ZFEN platform. Fenestrated cases were classified as primary FEVAR or reoperative FEVAR (rFEVAR) after previous EVAR or OSR. Cohort comparisons were performed using Fisher exac...

Journal of vascular surgery cases and innovative techniques, 2017

Large-vessel chronic traumatic arteriovenous fistulas are a rare complication after trauma. Delay... more Large-vessel chronic traumatic arteriovenous fistulas are a rare complication after trauma. Delayed presentation can consist of one or more features of high-output cardiac failure, pulsatile abdominal mass, bruit, limb ischemia, and venous congestion. We describe a patient with a complex iliocaval fistula secondary to a remote gunshot wound associated with a large 8.5-cm aortic aneurysm. Informed consent of the patient was obtained for publication of the case.

Annals of vascular surgery, Jan 5, 2018

Single-length saphenous vein continues to be the conduit of choice in infected-field critical lim... more Single-length saphenous vein continues to be the conduit of choice in infected-field critical limb ischemia. However, half of these individuals have inadequate vein secondary to previous use or chronic venous disease. We reviewed our outcomes of infected-field infrainguinal bypasses performed with cryopreserved homografts (CHs), a widely accepted alternative to autogenous vein in this setting. This is a retrospective, institutional descriptive analysis of infected-field infrainguinal revascularizations between 2012 and 2015. Twenty-four operations were performed in the same number of patients for limb ischemia with signs of active infection. The mean age of the cohort examined was 62.5 ± 14.4 (standard deviation) years. Mean Society of Vascular Surgery risk score was 3.9 with a baseline Rutherford's chronic ischemia score of 4.3 at presentation. Emergent procedures constituted 29% of cases, and the remainder cases were urgent procedures. The CH bypass captured was a reoperative ...

Annals of vascular surgery, Jan 22, 2018

The accepted treatment for acute limb ischemia (ALI) is immediate systemic anticoagulation and ti... more The accepted treatment for acute limb ischemia (ALI) is immediate systemic anticoagulation and timely reperfusion to restore blood flow. In this study, we describe the retrospective assessment of pretransfer management decisions by referring hospitals to an academic tertiary care facility and its impact on perioperative adverse events. A retrospective analysis of ALI patients transferred to us via our Level I Vascular Emergency program from 2010 to 2013 was performed. Patient demographics, comorbidities, Rutherford ischemia classification, time to anticoagulation, and time to reperfusion were tabulated and analyzed for correlation to incidence of major adverse limb events (MALE), mortality, and bypass patency in the perioperative period (30-day postoperative). All time intervals were calculated from the onset of symptoms and categorized into three subcohorts (<6 hrs, 6-48 hrs, and >48 hrs). Eighty-seven patients with an average age of 64.0 (± 16.2) years presented to outlying ...

Journal of vascular surgery, Aug 27, 2018

The Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent graft system was appro... more The Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent graft system was approved for commercial use by the Food and Drug Administration in April 2012. We report our single-center experience of 100 consecutive patients treated with the ZFEN platform from October 2012 to March 2017. A retrospective review of our prospectively maintained fenestrated endovascular aneurysm repair (FEVAR) database at a tertiary care academic institution located in the Midwest United States was performed for descriptive analysis. All continuous variables are reported as a mean ± standard deviation and compared using two-sided Student t-tests. Categorical variables were compared using two-sided Fisher exact tests. All but one of the procedures were elective in nature. Overall intraoperative characteristics included a mean blood loss (estimated blood loss) of 388 ± 385 mL, fluoroscopy time of 63 ± 30 minutes, radiation dose of 437 ± 272 rad, contrast material volume of 99 ± 36 mL, and ope...

Journal of vascular surgery, May 7, 2017

Acute limb ischemia (ALI) in infants poses a challenge to the clinician secondary to poor operati... more Acute limb ischemia (ALI) in infants poses a challenge to the clinician secondary to poor operative outcomes, limb loss risk, and lifelong morbidity. This retrospective study reviewed a 10-year institutional experience with the nonoperative management of ALI in infants. Infants (aged ≤12 months) diagnosed with ALI by duplex ultrasound and treated with initial nonoperative management at a tertiary care children's hospital were identified through vascular laboratory arterial duplex ultrasound records and International Classification of Diseases and Current Procedural Terminology codes associated with ALI. Demographics of the patients, injury characteristics, treatment administered, and outcomes were abstracted by chart review and presented using descriptive statistics. During the study period, a total of 25 (28% female) infant patients were diagnosed with ALI. The average age for this cohort was 3.5 ± 3.2 months (standard deviation). Most cases were secondary to iatrogenic injury ...