Effect of ischemia-reperfusion on outcomes after open mesenteric bypass for chronic mesenteric ischemia.

OBJECTIVE: Significant physiologic perturbations can occur in patients with chronic mesenteric ischemia (CMI) undergoing open mesenteric bypass (OMB). These events have frequently been attributed to ischemia-reperfusion events and have been directly implicated in the occurrence of multiple organ dysfunction (MOD). Scoring systems (MOD score [MODS] and sequential organ failure assessment [SOFA]) have been derived within the critical care field to provide a composite metric for these pathophysiologic changes. The purpose of the present study was to describe the early pathophysiologic changes that occur after OMB for CMI and determine whether these are predictive of the outcomes. METHODS: Patients with CMI who had undergone elective OMB from 2002 to 2018 at a single institution were reviewed. Changes in the hemodynamic, pulmonary, hepatic, renal, and hematologic parameters in the first 96 hours postoperatively were analyzed. The MODSs and SOFA scores were calculated. Cox regression was used to determine the association of the MODSs and SOFA scores with the outcomes. RESULTS: The use of OMB was analyzed for 72 patients (age, 66 ± 11 years; 68% women; body mass index, 23.8 ± 6 kg/m2; 48 ± 34-lb weight loss in 59%). Previous mesenteric stent placement or bypass had been performed in 39% [stenting in 21; bypass in 8; (one patient had both)]. An antegrade configuration (93%) was most common (retrograde configuration, 7%), with revascularization of the superior mesenteric artery/celiac vessels in 85% (superior mesenteric artery only in 15%). Postoperative pathophysiologic and metabolic changes were common, and the mean MODSs and SOFA scores were 3.6 ± 2.4 (range, 1-10) and 4.0 ± 2.7 (range, 1-13), respectively. The median length of stay was 14 days (interquartile range, 9-21). The 30-day mortality was 4% (n = 3) and in-hospital morbidity was 53% (n = 38; gastrointestinal, 25%; infectious, 22%; cardiac, 18%; pulmonary, 18%; renal, 11%). The clinical follow-up period was 16 ± 20 months. The MODSs and SOFA scores correlated linearly with overall mortality (MODS: odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.7; P < .01; SOFA score: OR, 1.4; 95% CI, 1.2-1.7; P < .01 per unit), with a score of ≥5 the inflection point most predictive of mortality (MODS: OR, 3.9; 95% CI, 1.6-9.9; P ≤ .01; SOFA score: OR, 2.8; 95% CI, 1.2-6.6; P = .02). The 1- and 3-year primary bypass patency and freedom from reintervention was 91% ± 5% and 83% ± 7%, respectively, with no association with the MODSs or SOFA scores. The 1- and 3-year survival was 86% ± 4% and 71% ± 6% with significantly worse outcomes for patients with higher MODSs and/or SOFA scores. CONCLUSIONS: Most CMI patients undergoing OMB will experience significant metabolic derangements resulting from sequelae of the ischemia-reperfusion phenomenon postoperatively. These can be objectively assessed in the early postoperative period using simply applied scoring systems to reliably predict the early and long-term outcomes. A derivation of the MODS and/or SOFA score after OMB for CMI can identify the most vulnerable patients at the greatest risk of mortality.

Contemporary outcomes of thoracofemoral bypass.

OBJECTIVE: Thoracofemoral bypass (TFB) is an alternative to aortofemoral bypass (AFB) or extra-anatomic bypass for severe aortoiliac occlusive disease (AIOD). TFB may be particularly useful in select patients with concurrent visceral aortic branch vessel disease, infrarenal aortic occlusions, or after failed AFB. However, there are few contemporary series describing the indications and outcomes for TFB. Therefore, the purpose of this analysis was to review our experience with TFB. METHODS: All patients undergoing TFB for occlusive disease from 2002 to 2017 were reviewed. All patients underwent left thoracoretroperitoneal exposure of the supraceliac aorta with division of the diaphragmatic crus and supraceliac cross-clamping. An end-to-side aortic anastomosis was created and each graft limb was tunneled in the retroperitoneum to the femoral bifurcation. Adjunctive visceral/infrainguinal revascularization was performed selectively based on symptoms, end-organ function, and/or preoperative imaging. The primary end points were major complications and 30-day mortality. Secondary end points included limb patency, freedom from major adverse limb events, and survival. Kaplan-Meier methodology was used to characterize the end points. RESULTS: Forty-one patients (age 61 ± 9 years; 54% female; 7% in a hypercoaguable state) underwent TFB. The mean preoperative ankle-brachial index was 0.4 bilaterally. Indications included critical limb ischemia (56%), claudication (30%), acute limb ischemia (7%), and combined AIOD and mesenteric ischemia (7%). Seven patients (17%) had previously undergone AFB and 15 (38%) had previously undergone any prior aortic operation. Adjunctive visceral bypass occurred in 8 patients (20%; N = 14 grafts, n = 6 renal, n = 5 superior mesenteric artery, and n = 3 celiac). The postoperative duration of stay was 11 days (interquartile range [IQR], 7-16 days) and the 30-day mortality was 5% (n = 2). Major complications occurred in 34% of patients (N = 14; pulmonary, 15%; cardiac, 12%; bleeding, 7%; accidental splenectomy, 5%; renal, 5%; wound, 2%). The mean postoperative ankle-brachial index was 0.9 bilaterally. At a median follow-up of 7 months (IQR, 1-17 months), 5 patients (12%) underwent some form of reintervention (graft/limb related, n = 4 [n = 2 graft thrombosis, n = 2 graft infection], n = 1 mesenteric bypass revision). The estimated 3-year primary limb patency and freedom from major adverse limb events were 80 ± 10%, and 70 ± 10%, respectively. The estimated 5-year survival was 93 ± 5% (median, 27.3; IQR, 14.5-35.2; 95% confidence interval, 17.9-32.8). CONCLUSIONS: This experience represents one of the largest and most current series of retroperitoneal TFB. We demonstrate that TFB can be performed with good outcomes for patients with severe AIOD, especially if concomitant visceral/infrainguinal reconstruction is warranted. These results support a continued role for TFB in select patients.

Hybrid management approach for superior mesenteric artery and branch aneurysms.

Visceral artery aneurysms are rare, with a 25% rupture risk and an associated 70% mortality. A 55-year-old woman with progressive epigastric pain was found to have multiple large superior mesenteric artery (SMA), branch, and gastroduodenal artery aneurysms along with an occluded celiac artery trunk with hepatic flow dependent on the aneurysm branch. Management included antegrade aortohepatic artery bypass with gastroduodenal artery ligation, followed by SMA stenting and aneurysm coiling. This case is novel, given the diffuse pattern and rarity of SMA and branch aneurysms. This hybrid surgical management highlights innovative strategies to minimize morbidity without compromising definitive treatment of complex visceral artery aneurysms.

Tibial artery duplex ultrasound-derived peak systolic velocities may be an objective performance measure after above-knee endovascular therapy for arterial stenosis.

OBJECTIVE: The ankle-brachial index (ABI) is a well-established measure of distal perfusion in lower extremity ischemia; however, the ABI is of limited value in patients with noncompressible lower extremity arteries. We sought to demonstrate whether duplex ultrasound-determined tibial artery velocities can be used as an alternative to ABI as an objective performance measure after endovascular treatment of above-knee arterial stenosis. METHODS: Thirty-six patients undergoing above-knee endovascular intervention had preprocedure and postprocedure duplex ultrasound examination within 6 months of intervention. Preprocedure vs postprocedure changes in tibial artery mean peak systolic velocity (PSV; mean of proximal, mid, and distal velocities) were compared with changes in ABI and a reference (control) cohort of 68 patients without peripheral vascular disease. RESULTS: Thirty-six patients (41 limbs) had an above-knee endovascular intervention and had preprocedure and postprocedure duplex ultrasound examinations of the ipsilateral extremity including the tibial arteries. Before the procedure, mean tibial artery PSVs in the 36 patients undergoing intervention were outside (below) the 95% confidence intervals for the control patients. In comparing preprocedure and postprocedure PSVs, the mean anterior tibial (P < .01), mean peroneal (P < .01), and mean posterior tibial (P < .01) PSVs all increased and correlated with an increase in ABI (P < .01). After endovascular intervention, duplex ultrasound-derived mean PSVs fell within or near established reference ranges for patients without peripheral arterial disease. Mean tibial artery PSV increases were similar in patients with and without noncompressible vessels. CONCLUSIONS: Tibial artery PSVs increase, correlate with an increase in ABI, and fall within or near confidence intervals for normal controls after above-knee endovascular interventions. After endovascular intervention, tibial artery PSVs can supplement ABI as an objective performance measure in patients with and in particular without compressible tibial arteries.

Intraluminal thrombus is associated with early rupture of abdominal aortic aneurysm.

BACKGROUND: The implications of intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) are currently unclear. Previous studies have demonstrated that ILT provides a biomechanical advantage by decreasing wall stress, whereas other studies have associated ILT with aortic wall weakening. It is further unclear why some aneurysms rupture at much smaller diameters than others. In this study, we sought to explore the association between ILT and risk of AAA rupture, particularly in small aneurysms. METHODS: Patients were retrospectively identified and categorized by maximum aneurysm diameter and rupture status: small (<60 mm) or large (≥60 mm) and ruptured (rAAA) or nonruptured (non-rAAA). Three-dimensional AAA anatomy was digitally reconstructed from computed tomography angiograms for each patient. Finite element analysis was then performed to calculate peak wall stress (PWS) and mean wall stress (MWS) using the patient's systolic blood pressure. AAA geometric properties, including normalized ILT thickness (mean ILT thickness/maximum diameter) and % volume (100 × ILT volume/total AAA volume), were also quantified. RESULTS: Patients with small rAAAs had PWS of 123 ± 51 kPa, which was significantly lower than that of patients with large rAAAs (242 ± 130 kPa; P = .04), small non-rAAAs (204 ± 60 kPa; P < .01), and large non-rAAAs (270 ± 106 kPa; P < .01). Patients with small rAAAs also had lower MWS (44 ± 14 kPa vs 82 ± 20 kPa; P < .02) compared with patients with large non-rAAAs. ILT % volume and normalized ILT thickness were greater in small rAAAs (68% ± 11%; 0.16 ± 0.04 mm) compared with small non-rAAAs (53% ± 16% [P = .02]; 0.11 ± 0.04 mm [P < .01]) and large non-rAAAs (57% ± 12% [P = .02]; 0.12 ± 0.03 mm [P < .01]). Increased ILT % volume was associated with both decreased MWS and decreased PWS. CONCLUSIONS: This study found that although increased ILT is associated with lower MWS and PWS, it is also associated with aneurysm rupture at smaller diameters and lower stress. Therefore, the protective biomechanical advantage that ILT provides by lowering wall stress seems to be outweighed by weakening of the AAA wall, particularly in patients with small rAAAs. This study suggests that high ILT burden may be a surrogate marker of decreased aortic wall strength and a characteristic of high-risk small aneurysms.

Arterial duplex for diagnosis of peripheral arterial emboli.

BACKGROUND: Whether duplex ultrasound (DUS) imaging alone can be used to successfully plan revascularization for peripheral arterial embolism (PAE) is unknown. This study evaluated the utility of DUS imaging alone for the diagnosis and treatment of PAE. METHODS: Patients with cardiogenic PAE to the lower or upper extremities during a 20-year period were retrospectively evaluated. Patients with visceral or cerebral PAE were excluded. Diagnosis by DUS imaging alone was compared with contrast angiography (CA) or computed tomography angiography (CTA). Patient demographics, use of intraoperative CA, need for reintervention, length of revascularization procedure, and rate of fasciotomy and amputation were compared. Mean peak systolic velocity (PSV; cm/s) measured at the proximal, middle, and distal segment of each artery from the common femoral to the distal tibial arteries was also compared with surgical outcomes. RESULTS: We identified 203 extremities in 182 patients with PAE. Preoperative imaging was obtained in 89%, including DUS imaging alone (44%), CA (37%), and CTA (7%). DUS imaging was used more frequently than CA or CTA in women, older patients, patients with congestive heart failure, upper extremity PAE, and patients on antiplatelet agents preoperatively. Use of intraoperative CA, need for reintervention, rate of fasciotomy and limb loss, and hospital length of stay were similar between the two groups. No upper extremities required amputation. Patients with lower extremity emboli who underwent fasciotomy had lower mean PSVs than those free from fasciotomy at the popliteal (4 ± 6 cm/s vs 31 ± 62 cm/s; P = .03), anterior tibial (1 ± 3 cm/s vs 10 ± 16 cm/s; P = .004), and posterior tibial (2 ± 3 cm/s vs 9 ± 15 cm/s; P = .03) arteries. The 30-day mortality for the series was 25% with a median follow-up of 7.4 months. The only predictor of 30-day mortality on multivariate analysis was tobacco use (odds ratio, 3.1; 95% confidence interval, 1.4-7.0). CONCLUSIONS: Surgical outcomes and survival for patients evaluated by preoperative DUS imaging alone for PAE are equivalent to patients evaluated with CA or CTA. PSVs in the tibiopopliteal arteries may predict the need for fasciotomy. Preoperative DUS imaging alone is sufficient for operative planning in patients with symptoms suggestive of PAE.

Aortic outflow occlusion predicts rupture of abdominal aortic aneurysm.

BACKGROUND: Current threshold recommendations for elective abdominal aortic aneurysm (AAA) repair are based solely on maximal AAA diameter. Peak wall stress (PWS) has been demonstrated to be a better predictor than AAA diameter of AAA rupture risk. However, PWS calculations are time-intensive, not widely available, and therefore not yet clinically practical. In addition, PWS analysis does not account for variations in wall strength between patients. We therefore sought to identify surrogate clinical markers of increased PWS and decreased aortic wall strength to better predict AAA rupture risk. METHODS: Patients treated at our institution from 2001 to 2014 for ruptured AAA (rAAA) were retrospectively identified and grouped into patients with small rAAA (maximum diameter <6 cm) or large rAAA (>6 cm). Patients with large (>6 cm) non-rAAA were also identified sequentially from 2009 for comparison. Demographics, vascular risk factors, maximal aortic diameter, and aortic outflow occlusion (AOO) were recorded. AOO was defined as complete occlusion of the common, internal, or external iliac artery. Computational fluid dynamics and finite element analysis simulations were performed to calculate wall stress distributions and to extract PWS. RESULTS: We identified 61 patients with rAAA, of which 15 ruptured with AAA diameter <60 mm (small rAAA group). Patients with small rAAAs were more likely to have peripheral arterial disease (PAD) and chronic obstructive pulmonary disease (COPD) than were patients in the large non-rAAA group. Patients with small rAAAs were also more likely to have AOO compared with non-rAAAs >60 mm (27% vs 8%; P = .047). Among all patients with rAAAs, those with AOO ruptured at smaller mean AAA diameters than in patients without AOO (62.1 ± 11.8 mm vs 72.5 ± 16.4 mm; P = .024). PWS calculations of a representative small rAAA and a large non-rAAA showed a substantial increase in PWS with AOO. CONCLUSIONS: We demonstrate that AOO, PAD, and COPD in AAA are associated with rAAAs at smaller diameters. AOO appears to increase PWS, whereas COPD and PAD may be surrogate markers of decreased aortic wall strength. We therefore recommend consideration of early, elective AAA repair in patients with AOO, PAD, or COPD to minimize risk of early rupture.

Management of catheter-associated upper extremity deep venous thrombosis.

Central venous catheters or peripherally inserted central catheters are major risk factors for upper extremity deep venous thrombosis (UEDVT). The body and quality of literature evaluating catheter-associated (CA) UEDVT have increased, yet strong evidence on screening, diagnosis, prevention, and optimal treatment is limited. We herein review the current evidence of CA UEDVT that can be applied clinically. Principally, we review the anatomy and definition of CA UEDVT, identification of risk factors, utility of duplex ultrasound as the preferred diagnostic modality, preventive strategies, and an algorithm for management of CA UEDVT.

Genetics, Pregnancy, and Aortic Degeneration.

We present a case of familial thoracic aortic aneurysm and dissection (FTAAD) in a pregnant female. FTAAD is an inherited, nonsyndromic aortopathy resulting from several genetic mutations critical to aortic wall integrity have been identified. One such mutation is the myosin heavy chain gene (MYH11) which is responsible for 1-2% of all FTAAD cases. This mutation results in aortic medial degeneration, loss of elastin, and reticulin fiber fragmentation predisposing to TAAD. Aortic disease is more aggressive during pregnancy as a result of increased wall stress from hyperdynamic cardiovascular changes and estrogen-induced aortic media degeneration. Our patient was a 29-year-old G2P1 woman at 26 weeks gestation presenting with abdominal and back pain. Work-up revealed a 6.4-cm ascending aortic aneurysm with a type A dissection extending into all arch vessels, aortic coarctation at the isthmus, and a separate focal type B aortic dissection with visceral involvement. Surgical management included concomitant cesarean section with delivery of a live premature infant, tubal ligation, ascending aortic replacement with reconstruction of the arch vessels, and aortic valve resuspension. The type B dissection was managed medically without complication. This is the first reported case of aortic dissection in a patient with FTAAD/MYH11 mutation and pregnancy. This case highlights that FTAAD and pregnancy cause aortic degeneration via distinct mechanisms and that hyperdynamics of pregnancy increase aortic wall stress. Management of pregnancy associated with aortopathy requires early transfer to a tertiary center, careful investigation to identify familial aortopathy, fetal monitoring, and a multidisciplinary team approach.

Outcomes of unilateral graft limb excision for infected aortobifemoral graft limb.

OBJECTIVE: Aortobifemoral graft (ABFG) infections presenting with apparent single-limb involvement can be managed with unilateral graft limb excision or complete graft removal. This study aimed to identify outcomes of unilateral graft limb excision for infected ABFGs and factors predictive of subsequent contralateral or main body graft limb infection. METHODS: A retrospective review of patients treated with unilateral graft limb excision for infection of an isolated limb of an ABFG from 2001 to July 2014 was performed. Endovascular and aortic tube graft infections were excluded. Outcomes were freedom from contralateral graft limb excision, overall survival, and factors predicting subsequent contralateral limb or main body infection. RESULTS: Fifteen patients underwent unilateral graft limb excision and revascularization for treatment of an infected ABFG isolated to one graft limb. Indications for the original ABFG were aortoiliac occlusive disease in 11 patients and aortoiliac aneurysm in 4 patients. All patients presented with clinical evidence consistent with unilateral graft limb infection and clinical findings confirmed radiographically. Unilateral graft explantation was performed for isolated infrainguinal graft limb infection with no retroperitoneal infection on exploration or if patients were too ill to tolerate total graft explantation despite infection in the retroperitoneum. Seven patients, all of whom underwent initial operation for aortoiliac occlusive disease, developed contralateral limb infection at a median follow-up of 23.2 months after unilateral excision. The remaining eight patients remained free of contralateral graft limb infection at median follow-up of 38.8 months. Patient demographics were similar between the two groups. Factors predictive of contralateral graft limb infection included an ABFG placed for aortoiliac occlusive disease (P = .03) and culture evidence of infection above the inguinal ligament (P = .07; positive predictive value of 71%). Median duration of targeted antibiotic therapy was 42 days, and neither duration of antibiotics nor cultured microorganism predicted recurrent graft infection. Overall mortality was 40% and was similar between patients who developed contralateral or main body graft infection and those who did not. There was no limb loss, and overall median follow-up was 44.7 months. CONCLUSIONS: Isolated unilateral infection of an ABFG limb can be managed with single graft limb excision, provided the infection is isolated to the infrainguinal graft segment. Factors predicting subsequent contralateral or main body graft infection include ABFGs originally placed for aortoiliac occlusive disease and culture-positive graft infection above the inguinal ligament.

Characterization of tibial velocities by duplex ultrasound in severe peripheral arterial disease and controls.

BACKGROUND: The relationship between tibiopopliteal velocities and peripheral arterial disease (PAD) severity is not well understood. We sought to characterize tibiopopliteal velocities in severe PAD and non-PAD control patients. METHODS: Patients with an arterial duplex ultrasound (DUS) examination with PAD evaluated during a 5-year period were retrospectively compared with non-PAD controls. Control DUS examinations were collected sequentially during a 6-month period, retrospectively. PAD patients included those with lifestyle-limiting intermittent claudication warranting revascularization and patients with critical limb ischemia, defined as ischemic rest pain, gangrene, or a nonhealing ischemic ulcer. For each, tibial and popliteal artery peak systolic velocity (PSV) was measured at the proximal, mid, and distal segment of each artery, and a mean PSV for each artery was calculated. Mean PSV, ankle-brachial indices, peak ankle velocity (PAV), average ankle velocity (AAV), mean tibial velocity (MTV), and ankle-profunda index (API) were compared between the two groups using independent t-tests. PAV is the maximum PSV of the distal peroneal, posterior tibial (PT), or anterior tibial (AT) artery; AAV is the average PSV of the distal peroneal, PT, and AT arteries; MTV is calculated by first averaging the proximal, mid, and distal PSV for each tibial artery and then averaging the three means together; API is the AAV divided by proximal PSV of the profunda. RESULTS: DUS was available in 103 patients with PAD (68 patients with critical limb ischemia and 35 patients with intermittent claudication) and 68 controls. Mean ankle-brachial index in the PAD group was 0.64 ± 0.25 compared with 1.08 ± 0.09 in controls (P = .006). Mean PSVs were significantly lower in PAD patients than in controls at the popliteal (64.6 ± 42.2 vs 76.2 ± 29.6; P = .037), peroneal (34.3 ± 26.4 vs 53.8 ± 23.3; P < .001), AT (43.7 ± 31.4 vs 65.4 ± 25.0; P < .001), and PT (43.4 ± 42.3 vs 74.1 ± 30.6; P < .001) and higher at the profunda (131.5 ± 88.0 vs 96.2 ± 44.8; P = .001). Tibial parameters including PAV (52.6 ± 45.0 vs 86.9 ± 35.7; P < .001), AAV (37.4 ± 26.4 vs 64.5 ± 21.7; P < .001), MTV (41.7 ± 30.4 vs 65.4 ± 21.7; P < .001), and API (0.43 ± 0.45 vs 0.75 ± 0.30; P < .001) were significantly lower in the PAD group than in controls. Nonoverlapping 95% confidence interval reference ranges were established for severe PAD and non-PAD controls. CONCLUSIONS: This study aims to characterize lower extremity arterial PSVs and ankle parameters in severe PAD and non-PAD controls. These early criteria establish reference ranges to guide vascular laboratory interpretation and clinical decision-making.

The Natural History of Indeterminate Blunt Cerebrovascular Injury.

IMPORTANCE: The Denver criteria grade blunt cerebrovascular injuries (BCVIs) but fail to capture many patients with indeterminate findings on initial imaging. OBJECTIVE: To evaluate outcomes and clinical significance of indeterminate BCVIs (iBCVIs). DESIGN, SETTING, AND PARTICIPANTS: A retrospective review of all patients treated for BCVIs at our institution from January 1, 2007, through July 31, 2014, was completed. Patients were divided into 2 groups: those with true BCVIs as defined by the Denver criteria and those with iBCVIs, which was any initial imaging suggestive of a cerebrovascular arterial injury not classifiable by the Denver criteria. MAIN OUTCOMES AND MEASURES: Primary outcomes were rate of resolution of iBCVIs, freedom from cerebrovascular accident (CVA) or transient ischemic attack (TIA), and 30-day mortality. RESULTS: We identified 100 patients with 138 BCVIs: 79 with true BCVIs and 59 with iBCVIs. With serial imaging, 23 iBCVIs (39.0%) resolved and 21 (35.6%) remained indeterminate, whereas 15 (25.4%) progressed to true BCVI. The rate of CVA or TIA in the iBCVI group was 5.1% compared with 15.2% in the true BCVI group (P = .06). Of the 15 total CVAs or TIAs, 11 (73.3%) resulted from carotid injury and 4 (26.7%) from vertebral artery occlusion (P = .03). By Kaplan-Meier analysis, there was no difference in freedom from CVA or TIA for the 2 groups (P = .07). Median clinical follow-up was 91 days. Overall and 30-day mortality for the entire series were 17.4% and 15.2%, respectively. There was no difference in long-term or 30-day mortality between true BCVI and iBCVI groups. CONCLUSIONS AND RELEVANCE: Detection of iBCVI has become a common clinical conundrum with improved and routine imaging. Indeterminate BCVI is not completely benign, with 25.4% demonstrating anatomical progression to true BCVI and 5.1% developing cerebrovascular symptoms. We therefore recommend serial imaging and antiplatelet therapy for iBCVI.

A modern series of acute aortic occlusion.

OBJECTIVE: Acute aortic occlusion (AAO) is a rare condition associated with substantial morbidity and mortality. The most recent large series was published over 15 years ago and included patients from the 1980s. Previous studies reported up to 50% of AAOs are caused by embolization, with a mortality rate approaching 50%. We reviewed our recent experience with AAOs to identify current etiologies and outcomes in a contemporary series of patients with AAOs. METHODS: Current Procedural Terminology codes and data from a prospectively maintained vascular surgical database were used to identify patients with acute occlusion of the native aorta between 2005 and July 2013. AAOs secondary to trauma, dissection, or graft occlusion were excluded. RESULTS: We identified 29 patients with AAOs treated at our institution. Twenty-three patients were transferred from referring hospitals with a mean transfer time of 3.9 hours (range, 0.5-7.5 hours). Twenty-two presented with occlusion below the renal arteries and seven with occlusion extending above the renal arteries. Resting motor/sensory lower extremity deficits were noted in 17 patients. Eight patients presented with complete paraplegia. Etiology was felt to be aortoiliac thrombosis in 22 cases, embolic occlusion in 2, and indeterminate in 5. Surgical revascularization was performed in 26 cases (extra-anatomic bypass in 18, thromboembolectomy in 5, and aortobifemoral bypass in 3 patients. Three patients had no intervention. Acute renal failure developed in 15 patients and rhabomyolysis in 10 patients. Fasciotomy was performed in 19 extremities. Nine extremities were amputated in six patients. Overall mortality was 34% with a 30-day mortality of 24% and a postprocedure mortality of 15%. CONCLUSIONS: AAO is an infrequent but devastating event. The dominant etiology of AAOs is now thrombotic occlusion. Despite advances in vascular surgery and critical care over the past 2 decades, associated morbidity and mortality remain substantial with high rates of limb loss, acute renal failure, rhabdomyolysis, and death. Mortality may be improved with expeditious extra-anatomic bypass.

Paroxysmal nocturnal hemoglobinuria: a red clot syndrome.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, nonmalignant disorder of hematopoietic stem cells characterized by hemolysis, diminished hematopoiesis, and thrombophilia. We describe a 65-year-old woman with known PNH and peripheral arterial disease who presented with critical limb ischemia and a nonhealing left foot ulcer. She underwent surgical bypass of a diffusely diseased left superficial femoral artery with autologous reversed saphenous vein graft. Her postoperative course was complicated by wound sepsis and PNH exacerbation with resultant graft thrombosis requiring an above-knee amputation. This case highlights several key concepts relevant to the management of vascular surgery patients with PNH: (1) their predisposition for arterial and venous thrombosis; (2) hypercoagulability despite standard anticoagulation regimens; (3) the role of eculizumab (a monoclonal antibody that inhibits complement activation used to treat PNH) in reducing thrombotic complications and hemolysis; and (4) complications associated with the immunosuppressive effects of eculizumab. We recommend careful monitoring of hemolysis and immunosuppression, aggressive anticoagulation, frequent graft surveillance, and early consultation with hematology.

Vasculogenic cytokines in wound healing.

Chronic wounds represent a growing healthcare burden that particularly afflicts aged, diabetic, vasculopathic, and obese patients. Studies have shown that nonhealing wounds are characterized by dysregulated cytokine networks that impair blood vessel formation. Two distinct forms of neovascularization have been described: vasculogenesis (driven by bone-marrow-derived circulating endothelial progenitor cells) and angiogenesis (local endothelial cell sprouting from existing vasculature). Researchers have traditionally focused on angiogenesis but defects in vasculogenesis are increasingly recognized to impact diseases including wound healing. A more comprehensive understanding of vasculogenic cytokine networks may facilitate the development of novel strategies to treat recalcitrant wounds. Further, the clinical success of endothelial progenitor cell-based therapies will depend not only on the delivery of the cells themselves but also on the appropriate cytokine milieu to promote tissue regeneration. This paper will highlight major cytokines involved in vasculogenesis within the context of cutaneous wound healing.

Routine completion axillary lymph node dissection for positive sentinel nodes in patients undergoing mastectomy is not associated with improved local control.

BACKGROUND: The current practice of completion axillary lymph node dissection (ALND) for patients with a positive sentinel lymph node (SLN) is being questioned. This led us to examine the outcomes of patients with positive SLNs undergoing mastectomy who underwent ALND compared with those who did not. METHODS: A retrospective review of cancer registry data identified 561 women with stages 1 to 3 breast cancer with positive SLNs who underwent mastectomy between 2000 and 2010. Four hundred twenty-six women underwent formal ALND and 135 were managed expectantly. Recurrence-free survival was defined as no locoregional or distant metastases. RESULTS: Mean time to recurrence was 29.9 months. Mean follow-up for patients without recurrence was 40.3 months. Survival curves showed no significant difference in recurrence-free survival between the 2 groups (P = .23). CONCLUSIONS: In our experience, there is no significant difference in recurrence-free survival in patients with positive SLNs undergoing mastectomy when completion ALND was not performed, suggesting that a closer look at the indications for ALND in early breast cancer be further explored.

Regulatory effects of estrogen on acute lung inflammation in mice.

The role of estrogen in the regulation of the inflammatory response is not well defined. In this study, we investigated the effects of ovarian hormones on the acute inflammatory response in mouse lungs. Acute lung injury was induced by intratracheal instillation of bacterial lipopolysaccharide (LPS) in male, female, and ovariectomized (OVX) mice. End points of injury were polymorphonuclear neutrophil (PMN) content in bronchoalveolar lavage (BAL) fluids, myeloperoxidase activity in whole lung, and leak of albumin into the lung. After intratracheal instillation of LPS, all end points of injury were substantially increased in male and OVX mice compared with the female mice with intact ovaries. BAL fluids of all mice showed similar levels of chemokines (macrophage inflammatory protein MIP-2, KC, and monocyte chemoattractant proteins MCP-1 and MCP-3) and TNF-alpha, but enhanced levels of IL-1beta were found in OVX and male mice. Serum levels of IL-6 and ICAM-1 levels in lung homogenates from OVX and male mice, compared with those in female mice with intact ovaries, were also enhanced after instillation of LPS. Albumin and PMN content in LPS-injured lungs were reduced to levels found in female mice after administration of estradiol in OVX mice and corresponded to reduced IL-1beta, IL-6, and ICAM-1 levels. These data suggest that estrogen suppresses lung inflammatory responses in mice through an effect on vascular cell adhesion molecules and proinflammatory mediators.