Insulin Requirement and Infrainguinal Bypass Outcomes in Patients with Peripheral Arterial Disease.

BACKGROUND: Diabetes mellitus (DM) is a major risk factor for peripheral artery disease. The association of DM with major adverse limb events (MALE) after lower extremity revascularization remains controversial, as patients with diabetes are typically analyzed as a single, homogenous group. Using a large national database, this study examines the impact of insulin use and glycemic control on the outcomes following infrainguinal bypass. The hypothesis is that prevalent insulin therapy and elevated hemoglobin A1c (HbA1c) are associated with an increased risk of MALEs after infrainguinal bypass in patients with DM and could therefore be used for risk stratification. METHODS: The Vascular Quality Initiative database files for infrainguinal bypass (2007-2021) were retrospectively reviewed. Patients with DM undergoing bypass for peripheral artery disease were included. Patients on dialysis or with prior kidney transplantation were excluded. The characteristics and outcomes of patients with insulin-requiring diabetes mellitus (IRDM) were compared to those of patients not requiring insulin (noninsulin-requiring diabetes mellitus [NIRDM]) prior to the bypass procedure. RESULTS: A total of 9,686 patients with DM (56% IRDM) underwent bypass. Patients with IRDM were significantly younger than patients with NIRDM, more likely to be female (P < 0.01), African American (P < 0.01), and Hispanic (P = 0.031), and more likely to have comorbidities and be categorized into American Society of Anesthesiologist classes IV-V. They were more likely to be treated for chronic limb-threatening ischemia (P < 0.001). Patients with IRDM had significantly higher perioperative complications with no difference in perioperative mortality between the 2 groups. Beyond the perioperative period, with a mean follow-up of 427 days, patients with IRDM had significantly lower crude rates of primary patency and higher crude rates of major amputation, MALE, and mortality compared to patients with NIRDM. Regression analyses demonstrated that insulin requirement, but not HbA1c, was independently associated with a higher risk of MALE (hazard ratio = 1.17 [1.06-1.29]) and mortality (hazard ratio = 1.28 [1.16-1.43]). CONCLUSIONS: Insulin requirement, but not HbA1c, is significantly associated with MALEs and survival after infrainguinal bypass in the Vascular Quality Initiative. Stratification of patients with DM based on their prevalent insulin use prior to infrainguinal bypass surgery could improve the prediction of outcomes of peripheral arterial bypass surgery in patients with diabetes.

Perioperative complications of minor and major reinterventions for peripheral arterial disease.

INTRODUCTION: Patients with peripheral arterial disease (PAD) frequently require reinterventions after lower-extremity revascularization (LER) to maintain perfusion. Current Society for Vascular Surgery guidelines define reinterventions as major or minor based on the magnitude of the procedure. While prior studies have compared primary LER procedures of different magnitudes, similar studies for reinterventions have not been performed. The objective of this study is to compare perioperative outcomes associated with major and minor reinterventions. METHODS: Patients undergoing LER for PAD at a tertiary care center from 2013 to 2017 were included. A retrospective review of electronic medical records was performed, and reinterventions were categorized as major or minor based on the procedure magnitude. Minor reinterventions included endovascular procedures and open revision with patch angioplasty, while major reinterventions were characterized by open surgical or endovascular LER with catheter-directed thrombolysis (CDT). Perioperative outcomes following LER were captured and compared for major and minor reinterventions. An additional subgroup analysis was performed comparing outcomes associated with major reinterventions stratified into open major surgical reinterventions and CDT. RESULTS: This study included 713 patients over a mean follow-up of 2.5 years. A total of 291 patients underwent 696 ipsilateral reinterventions (range = 1-12 reinterventions). Most reinterventions were minor (72.1%, N = 502) and 27.9% (N = 194) were major. Patients receiving reinterventions had an average age of 67.2 ± 11.5 and most were white (73.5%) males (60.1%) initially treated for claudication (58.2%) and CLTI (41.8%). There was significantly higher post-operative bleeding (9.8% vs 3.4%, p = .001), arterial thrombosis (3.1% vs 1.0%, p = .047), and acute renal failure (6.2% vs 2.4%, p = .014) after major reinterventions than minor. Additionally, major reinterventions had significantly higher return to the OR (17.0% vs 11.3%, p = .046) and longer hospital stays (7.5 vs 4.3 days, p = <.0001). Overall, major reinterventions were associated with significantly increased perioperative morbidity (37.6% vs 19.7%, p ≤ .001) with no difference in perioperative mortality. In the subgroup analysis, open reinterventions resulted in significantly longer hospital stays (8.6 days vs 5.5 days, p ≤ .001) and more wound infections than CDT (11.0% vs 0%, p = .017). However, there was no other significant difference in morbidity or mortality following treatment with open surgical reinterventions or CDT. CONCLUSIONS: In this study, major reinterventions after LER were associated with greater perioperative morbidity than minor reinterventions, with no difference in mortality. Major reinterventions performed via open surgery and CDT had similar morbidity and mortality.

Sex hormones impact early maturation and immune response in the arteriovenous fistula mouse model.

Arteriovenous fistulae (AVF) fail to mature more frequently in female patients compared with male patients, leading to inferior outcomes and decreased utilization. Since our mouse AVF model recapitulates sex differences in human AVF maturation, we hypothesized that sex hormones mediate these differences during AVF maturation. C57BL/6 mice (9-11 wk) were treated with aortocaval AVF surgery and/or gonadectomy. AVF hemodynamics were measured via ultrasound (days 0-21). Blood was collected for FACS and tissue for immunofluorescence and ELISA (days 3 and 7); wall thickness was assessed by histology (day 21). Inferior vena cava shear stress was higher in male mice (P = 0.0028) after gonadectomy, and they had increased wall thickness (22.0 ± 1.8 vs. 12.7 ± 1.2 µm; P < 0.0001). Conversely, female mice had decreased wall thickness (6.8 ± 0.6 vs. 15.3 ± 0.9 µm; P = 0.0002). Intact female mice had higher proportions of circulating CD3+ T cells on day 3 (P = 0.0043), CD4+ (P = 0.0003) and CD8+ T cells (P = 0.005) on day 7, and CD11b+ monocytes on day 3 (P = 0.0046). After gonadectomy, these differences disappeared. In intact female mice, CD3+ T cells (P = 0.025), CD4+ T cells (P = 0.0178), CD8+ T cells (P = 0.0571), and CD68+ macrophages (P = 0.0078) increased in the fistula wall on days 3 and 7. This disappeared after gonadectomy. Furthermore, female mice had higher IL-10 (P = 0.0217) and TNF-α (P = 0.0417) levels in their AVF walls than male mice. Sex hormones mediate AVF maturation, suggesting that hormone receptor signaling may be a target to improve AVF maturation.NEW & NOTEWORTHY After arteriovenous fistula creation, females have lower rates of maturation and higher rates of failure than males. In a mouse model of venous adaptation that recapitulates human fistula maturation, sex hormones may be mechanisms of the sexual dimorphism: testosterone is associated with reduced shear stress, whereas estrogen is associated with increased immune cell recruitment. Modulating sex hormones or downstream effectors suggests sex-specific therapies and could address disparities in sex differences in clinical outcomes.

Virtual vascular surgery interest group during the coronavirus disease 2019 pandemic.

OBJECTIVES: Early exposure to vascular surgery at the medical student level positively influences one's decision to apply into an integrated vascular surgery residency program. Vascular surgery interest groups (VSIGs) are student-run and aim to facilitate such exposure, traditionally via in-person events. Social distancing during the coronavirus disease 2019 pandemic disrupted these interactions. This is a description of the virtual activities of a VSIG group during the 2020-2021 academic year and highlights their impact among medical students. METHODS: The virtual activities of the VSIG at the Yale School of Medicine were reviewed. Students received surveys prior and after activities to assess their impact. Preactivity and postactivity surveys using Likert scale (1 = completely disagree; 5 = completely agree) were administered and compared. Statistical significance was achieved with a P value of less than .05. RESULTS: A total of five virtual events were held: an Introductory Session (October 2020), a Simulation Session (November 2020), a Research Night (January 2021), a Journal Club (February 2021), and a National Match Panel (April 2021). The surveys of three events (Introductory Session, Simulation Session, and National Match Panel) were analyzed. Attendance at these events were 18, 55, and 103 respectively. The average presurvey response rate was 51.2% and the average postsurvey response rate was 27.46%. Students agreed that the Introductory Session increased their knowledge about vascular surgery as a subspecialty (4.22 ± 0.67) and that the session was valuable to their time (4.33 ± 1.00). The Simulation Session increased student's comfort with knot tying from 1.73 ± 0.89 to 3.21 ± 1.25 (P < .001). Students reported an increased understanding of residency program selection (2.39 ± 1.10 vs 3.21 ± 1.12; P = .018), the Electronic Residency Application Service application (2.16 ± 1.01 vs 3.00 ± 0.88; P = .007), and letters of recommendation (2.45 ± 1.07 vs 3.14 ± 1.17; P = .04). Students particularly had a significant increase in the understanding of the logistics of residency interviews, which were held virtually that year for the first time (1.84 ± 0.96 vs 3.29 ± 1.20; P < .001). CONCLUSIONS: Virtual VSIG activities were feasible and effective during the pandemic in promoting student engagement and interest in vascular surgery. Despite lifting social distancing measures, the virtual format could become a valuable tool to expand outreach efforts of the vascular surgery community to recruit talented medical students.

The management of patients with popliteal artery aneurysms presenting with acute limb ischemia.

OBJECTIVE: Endovascular popliteal artery aneurysm (PAA) repair has acceptable outcomes compared with open repair for elective therapy. Endovascular repair for urgent PAA causing acute limb ischemia (ALI) has not been well-studied. This project compares outcomes of urgent endovascular and open repair of PAA with ALI. METHODS: The Vascular Quality Initiative database for peripheral vascular interventions (PVIs) and infrainguinal bypass were reviewed for PAAs with ALI from 2010 to 2021. Only patients entered as having symptoms of ALI in the PVI module and ALI as indication in the infrainguinal bypass module were included. In addition, patients undergoing elective treatment were excluded and the sample analyzed was restricted to patients undergoing urgent and emergent open and endovascular repair. Patient demographics and comorbidities as well as procedural details were compared between the two groups. Perioperative complications up to 30 days were compared as well as long-term outcomes including major amputation and mortality at 1 year. RESULTS: Urgent PAA repair for ALI constituted 10.5% (n = 571) of all PAAs. Most urgent repairs were open (80.6%; n = 460) with 19.4% (n = 111) endovascular. The proportion of endovascular repair significantly increased from 16.7% in 2010 to 85.7% in 2021. Patients undergoing endovascular repair were older (71.2 ± 12.5 vs 68.0 ± 11.8; P = .011) than patients undergoing open repair. They were also more likely to have coronary artery disease (32.4% vs 21.7%; P = .006). Open PAA repair was associated with more bleeding complications (20.8% vs 2.7%; P < .001), longer postoperative length of stay (8.1 ± 9.3 days vs 4.9 ± 5.6 days; P < .001), and less likelihood of discharge to home (64.9% vs 70.3%; P = .051). Perioperative major amputation rate was 7.5% with no difference between the two treatment strategies up to 1 year. However, patients receiving endovascular repair had higher inpatient (1.1% vs 0%; P < .001), 30-day (6.3% vs 0.4%; P < .001), and 1-year (16.5% vs 8.4%; P = .02) mortality. Multivariable regression analysis suggested that endovascular repair was possibly associated with increased 30-day mortality, but not 1-year mortality. CONCLUSIONS: Endovascular PAA has exponentially increased from 2010 to 2021. Endovascular repair is associated with decreased complications and hospital length of stay. The increased perioperative mortality seen in this group is likely due to selection bias.

Arterial Diameter and Percentage of Monocytes are Sex-Dependent Predictors of Early Arteriovenous Fistula Maturation.

BACKGROUND: Arteriovenous fistulae mature less frequently in women than in men, leading to inferior patency and decreased fistula utilization in women. We hypothesized that both anatomic and physiologic sex differences explain reduced maturation. METHODS: The electronic medical records of patients who had a primary arteriovenous fistula created from 2016 to 2021 at a single center were reviewed; sample size was determined using a power calculation. Postoperative ultrasound and laboratory tests were obtained at least 4 weeks after fistula creation. Primary unassisted fistula maturation was determined up to 4 years postprocedure. RESULTS: A total of 28 women and 28 men with a brachial-cephalic fistula were analyzed. The inflow brachial artery diameter was smaller in women than in men, both preoperatively (4.2 ± 0.9 vs. 4.9 ± 1.0 mm, P = 0.008) and postoperatively (4.8 ± 0.8 vs. 5.3 ± 0.9 mm, P = 0.039). Despite similar preoperative brachial artery peak systolic velocity, women had significantly lower postoperative arterial velocity (P = 0.027). Fistula flow was reduced in women, particularly in the midhumerus (747.0 ± 570.4 vs. 1,117.1 ± 471.3 cc/min, P = 0.003). Percentages of neutrophils and lymphocytes were similar among women and men 6 weeks after fistula creation. However, women had reduced monocytes (8.5 ± 2.0 vs. 10.0 ± 2.6%, P = 0.0168). Among 28 men, 24 of 28 (85.7%) achieved unassisted maturation, whereas only 15 of 28 (53.6%) women had fistulae that matured without intervention. Secondary analysis using logistic regression suggested that postoperative arterial diameter was associated with maturation in men, while postoperative monocyte percentage was associated with maturation in women. CONCLUSIONS: Sex differences during arteriovenous fistula maturation are present in arterial diameter and velocity, suggesting that both anatomic and physiologic differences in arterial inflow contribute to sex differences in fistula maturation. In men, postoperative arterial diameter is correlated with maturation, whereas in women, the significantly lower proportion of circulating monocytes suggests a role for the immune response in fistula maturation.

Incidence and Significance of Deep Venous Reflux in Patients Treated with Saphenous Vein Ablation.

BACKGROUND: Venous ablation (VA) of the saphenous vein is the most common procedure performed for venous insufficiency. The incidence of concomitant deep venous reflux (DVR) in patients undergoing VA is unknown. Our hypothesis is that patients undergoing saphenous VA with concomitant DVR exhibit a higher clinical, etiology, anatomy, and pathophysiology (CEAP) stage and less relief after VA compared to patients without DVR. METHODS: Electronic medical records of patients treated with saphenous VA at a tertiary care center from March 2012 to June 2016 were reviewed. Patients were divided into 2 groups based on presence or absence of DVR on initial ultrasound (US) before saphenous VA. Patient characteristics and outcomes were compared. A telephone survey was conducted to assess long-term symptomatic relief, compliance with compression, and pain medication use. Subgroup analysis of patients with post-thrombotic versus primary DVR was performed. RESULTS: 362 patients underwent 497 ablations, and the incidence of DVR (>1 sec) was 20% (N = 71). Patients with DVR were significantly more likely to be male (46.4% vs. 32.1%, P = 0.021) and of Black race (21.2% vs. 5.5%, P = 0.0001) compared to patients without DVR. Patients with DVR were more likely to have a history of deep vein thrombosis (DVT) (15.1% vs. 7.9%, P = 0.045), but there was no difference in other comorbidities. There was no significant difference in presenting symptoms, CEAP stage, or symptom severity based on numeric rating scale (NRS) (0-10) for pain and swelling. Clinical success of saphenous VA was comparable between the 2 groups, but patients with DVR were more likely to develop endovenous heat-induced thrombosis (EHIT) II-IV (6% vs. 1%, P = 0.002). After a mean follow-up of 26 months, there was still no difference in pain or swelling scores, but patients with DVR were more likely to use compression stockings and used them more frequently. Only 11 of 71 patients with DVR had a history of DVT. Patients with post-thrombotic DVR were significantly older than patients with primary DVR (67.3 vs. 57.2, P = 0.038) and exhibited a trend toward more advanced venous disease (C4-C6: 45.4% vs. 33.3%, P = 0.439). CONCLUSIONS: In this study, 20% of patients undergoing saphenous VA demonstrated DVR, which was more common in Black men. Presence of DVR is associated with increased risk of EHIT after saphenous VA but does not seem to impact disease severity or clinical relief after ablation. Larger studies are needed to understand outcome differences between post-thrombotic and primary DVR.

Eligibility of Patients with Chronic Limb Threatening Ischemia for Deep Venous Arterialization.

BACKGROUND: Percutaneous deep venous arterialization (pDVA) has emerged as a new modality for limb salvage in patients with chronic limb threatening ischemia (CLTI) and no standard option for revascularization. The proportion of patients facing major amputation who are eligible for this technology remains unknown. This study aims to provide a real-life estimate of patient eligibility for pDVA to reduce major amputations. METHODS: Electronic medical records of 100 consecutive patients with peripheral arterial disease (PAD) who underwent major amputation of 106 limbs were reviewed. Angiograms performed ≤6 months before amputation were assessed by two vascular surgeons. Disease severity was categorized using the Global Limb Anatomic Staging System (GLASS) and patients were classified as ideal, possible, or not candidates for pDVA. Ideal candidates had ≥1 patent tibial artery, no target in the foot, and no proximal disease. Possible candidates had ≥1 patent tibial artery with PAD, no target in the foot, and proximal disease amenable to endovascular therapy. Patients were not eligible if there was no patent tibial artery, extensive PAD, or an arterial target in the foot for bypass. RESULTS: Of 106 limbs reviewed, 35 (33%) did not undergo angiography ≤6 months before amputation because of infection (n = 14), advanced tissue loss (n = 10), failed revascularizations (n = 8), advanced limb ischemia (n = 2), and refusing revascularization (n = 1). Thus, 69 lower extremity angiograms (2 incomplete excluded) in 68 patients were analyzed. A total of 15 patients with 16 limbs (23.2%) were identified as candidates for pDVA (ideal = 7, possible = 9). There were no differences in demographics between the two groups, but candidates for pDVA were less likely to have hyperlipidemia and congestive heart failure than those who were not candidates. The pDVA candidates underwent significantly fewer interventions before major amputation compared to patients who were not candidates (1.50 ± 0.73 vs. 2.61 ± 2.57, P = 0.007). Angiographically, patients who were pDVA candidates had significantly higher Inframalleolar GLASS grades (1.81 ± 0.40 vs. 0.86 ± 0.41, P < 0.0001) but lower Femoropopliteal Glass grades (0.73 ± 1.10 vs. 2.43 ± 1.71, P < 0.0001) than patients who were not candidates. There was no significant difference in GLASS stage between these two groups (P = 0.368). After mean follow-up of 48 months, there was no difference in mortality between both groups (40% vs. 32.1%, P = 0.567). CONCLUSIONS: Among patients considered for revascularization, 23.2% had favorable angiography and 14.7% could have benefited for pDVA as a new therapeutic modality for limb salvage. 33% of major amputations were performed for clinically-deemed unsalvageable CLTI.

Hybrid repair of an innominate artery pseudoaneurysm after blunt traumatic injury in a bovine arch.

Innominate artery injury is an uncommon consequence of blunt trauma to the neck due to its protected position behind the thorax. A 38-year-old male presented as a trauma with a right-sided pseudoaneurysm emanating from the distal innominate artery after falling from a three-story building. On imaging, he also had a bovine arch. He underwent hybrid repair with covered stent placement from the common carotid into the innominate artery, carotid-subclavian bypass, and plugging of the subclavian artery. The patient recovered with no cerebral insult, neurological deficits, or rupture. Post-traumatic innominate artery pseudoaneurysms can successfully be repaired via a hybrid surgical approach.

Arm ischemia in a 4-year-old boy with supracondylar fracture of the humerus due to constraining bands over the brachial artery.

Supracondylar humerus fractures are common in children and can compromise the brachial artery in 5% to 15% of cases. A 4-year-old boy with a left supracondylar fracture developed upper extremity ischemia after pinning of the fracture. Computed tomography angiography revealed cutoff of flow in the brachial artery. Intraoperatively, he was found to have bands tethering the artery into the fracture, obstructing the blood flow. The orthopedic pins were removed, and the constraining bands were lysed to free the artery, with reconstitution of flow confirmed by intraoperative angiography. The fracture was reduced and stabilized, and the patient recovered well with normal arterial flow on follow-up ultrasound after 3 months.

Endovascular fenestration and iliac stenting for acute limb ischemia caused by type B aortic dissection.

A 60-year-old man presented with chest pain and acute limb ischemia of the right leg. He was found to have a type B aortic dissection with a flap occluding the origin of the right common iliac artery. The dissection flap was fenestrated endovascularly with the placement of a covered stent in the right common iliac artery. After 10 years, the dissection remains stable with a minimal increase in the aorta size. The stent is patent with no lower extremity symptoms or reintervention. Fenestration and stenting of the obstructing flap can be a durable reperfusion strategy for patients with aortic dissection presenting with acute limb ischemia.

Aneurysmal degeneration of the hood of a cryopreserved vein allograft two years after thrombosis.

Cryopreserved vein allografts are used as alternative conduits for infrainguinal bypass but are prone to aneurysmal degeneration. A 60-year-old man presented with a pulsatile, tender right groin mass 2 years after thrombosis of a cryopreserved vein jump graft emanating from a prosthetic axillary to profunda bypass. Intraoperatively, the aneurysm was consistent with isolated dilatation of the hood of the thrombosed cryopreserved vein graft. This was excised and repaired with bovine pericardial patch angioplasty. The patient recovered with no recurrence for 2 years. Aneurysmal degeneration of the cryopreserved vein allograft can occur even after graft thrombosis.

Endovascular revascularization of an occluded persistent sciatic artery for chronic limb-threatening ischemia in a patient with Coronavirus Disease 2019.

A persistent sciatic artery (PSA) is a rare embryologic variant that usually presents with aneurysmal degeneration. This report describes a 66-year-old man with severe comorbidities who presented with right forefoot gangrene and severe acute respiratory syndrome coronavirus 2 infection. Imaging revealed a unilateral PSA with a chronic occlusion at the level of the knee joint with no aneurysm. After coronavirus disease 2019 resolution, he underwent CO2 angiography with successful recanalization of the PSA, followed by transmetatarsal amputation that healed uneventfully. At follow-up after 16 months, he was noted to have asymptomatic thrombosis of his stent and, hence, no intervention was performed.

Echocardiographic Evaluation of the Thoracic Aorta: Tips and Pitfalls.

By convention, the ascending aorta is measured by echo from leading edge to leading edge. "Leading edge" connotes the edge of the aortic wall that is closest to the probe (at the top of the inverted "V" of the ultrasound image). By transthoracic echo (TTE), the leading edges are the outer anterior wall and inner posterior wall. By transesophageal echo (TEE), the leading edges are the outer posterior wall and inner anterior wall. Aortic measurements should be taken (by convention) in diastole (when the aorta is moving least). Simple TTE is 70 to 85% sensitive in diagnosing ascending aortic dissection. TEE sensitivity approaches 100%, though the tracheal carina imposes a blind spot on TEE, impeding visualization of distal ascending aorta and proximal aortic arch. While computed tomography angiography may be superior for defining full anatomic extent of aortic dissection, echocardiography is superior in assessing functional consequences such as mechanism and severity of aortic regurgitation, evidence of myocardial ischemia when complicated by coronary dissection, or evidence of tamponade physiology when pericardial effusion is present. Reverberation artifact can mimic a dissection flap. A true flap moves independently of the outer aortic wall which can be confirmed by M-mode. Color flow respects a true flap but does not respect a reverberation artifact. Assessment for bicuspid aortic valve (BAV) morphology should be done in systole, not diastole. In diastole, when the valve is closed, the raphé can make a bicuspid valve appear trileaflet. Doming in the parasternal long axis (PLAX) view and an eccentric closure line on PLAX M-mode should also raise suspicion for BAV.