Aggressive Treatment Strategy at Index TEVAR Is Associated With Reduced Need For Short-Term Reintervention In Patients With Aortic Dissection.

INTRODUCTION: Thoracic endovascular aortic surgery (TEVAR) is the modern standard of treatment for patients with Type B aortic dissection, however it is unclear how the initial length of treated aorta affects long-term outcomes. This study aims to elucidate risk factors for secondary intervention after TEVAR for aortic dissection, focusing on length of aortic treatment at index operation. METHODS: A retrospective multihospital chart review was completed for patients treated between 2011 and 2022 who underwent TEVAR for aortic dissection with at least one year of post-TEVAR imaging and follow-up. Patient demographics and characteristics were analyzed. In this study, aortic zones treated only included those managed with a covered stent graft. The primary outcome measure was any need for secondary intervention. RESULTS: A total of 151 patients were identified. Demographics included a mean age of 57 years, with 31.8% of the patients being female. Forty-three patients (28.5%) underwent secondary intervention after TEVAR, with a mean follow-up of 1.6 years. The most common indication for secondary intervention was aneurysmal degeneration of the residual false lumen (76%). There was a significant difference in the number of aortic zones treated in patients who did and did not require secondary intervention (2.3 ± 1 vs. 2.7 ± 1, p = 0.04). Additionally, patients with three or more aortic zones of treatment had a significant difference in the need for reintervention (32% secondary intervention vs 52% no secondary intervention, p = 0.02). CONCLUSIONS: At least three zones of aortic treatment at index TEVAR is associated with a decreased need for overall reintervention. Modern treatment of acute and subacute type B dissection should stress an aggressive initial repair, balanced by the potential increased risk of spinal cord ischemia.

The Characteristics and Results of Endovascular Devices in Trauma (CREDiT) study: Multi-institutional results.

INTRODUCTION: Endovascular techniques are increasingly used to repair major traumatic vascular injuries, but most endovascular implants are not designed/approved for trauma-specific indications. No inventory guidelines exist for the devices used in these procedures. We aimed to describe the use and characteristics of endovascular implants used for repair of vascular injuries to allow for better inventory management. METHODS: This CREDiT study is a six-year retrospective cohort analysis of endovascular procedures performed for repair of traumatic arterial injuries at five participating US trauma centers. For each treated vessel, procedural and device details were recorded and outcomes assessed with the aim of defining the range of implants and sizes used for these interventions. RESULTS: A total of 94 cases were identified; 58 (61%) were descending thoracic aorta, 14 (15%) axillosubclavian, 5 carotid, 4 abdominal aortic, 4 common iliac, 7 femoropopliteal, and 1 renal. Vascular surgeons performed 54% of cases, trauma surgeons 17%, IR/CT Surgery 29%. Systemic heparin was administered in 68% and procedures were performed a median of 9 h after arrival (IQR 3-24 h). Primary arterial access was femoral in 93% of cases, 49% were bilateral. Brachial/radial access was used primarily in 6 cases, and secondary to femoral in 9. The most common implant was self-expanding stent graft; 18% used >1 stent. Implants ranged in diameter and length based on vessel size. Five of 94 implants underwent reintervention (1 open surgery) at a median of 4d postop (range 2-60d). Two occlusions and 1 stenosis were present at follow-up at a median of 1 month (range 0-72 m). CONCLUSIONS: Endovascular reconstruction of injured arteries requires a broad range of implant types, diameters, and lengths which should be readily available in trauma centers. Stent occlusions/stenoses are rare and can typically be managed by endovascular means.

Missing Bullets: Bullet Embolization Case Series and Review of the Literature.

PURPOSE: Bullet embolization is a rare but dangerous phenomenon. Based on the location of embolization, migration of bullets can cause limb or intra-abdominal ischemia, pulmonary infarction, cardiac valve injury, or cerebrovascular accident. Bullet emboli can present a diagnostic challenge given the varied nature of complications based on location of embolization, which may not coincide with the site of initial injury. The purpose of this study is to present several cases of bullet embolization from our busy urban trauma center and make recommendations for management. METHODS: We present 3 cases of bullet embolization seen in injured patients at our Level 1 trauma center. We describe our management of these injuries and make recommendations for management in the context of our institutional experience and comment on the available literature regarding bullet embolization. RESULTS: Two of our patients presented in extremis and required operative intervention to achieve stability. The intravascular missile was discovered intraoperatively in one patient and removed in the operating room, while the missile was discovered on postoperative imaging in another patient and again removed operatively after an unsuccessful attempt at minimally invasive retrieval. Our third patient remained hemodynamically stable throughout his hospitalization and had endovascular management of his bullet embolus. CONCLUSION: Bullet emboli present a challenging complication of penetrating trauma. We recommend removal of all arterial bullet emboli and those within the pulmonary venous system. In hemodynamically stable patients, we recommend initial attempts of endovascular retrieval followed by open surgical removal. We recommend open removal in cases of hemodynamic instability.

Vascular surgery is the most commonly consulted specialty for emergent operative trauma.

OBJECTIVE: Despite an increasing rate of intraoperative consultation of vascular surgery (VS) for trauma patients, VS is not one of the subspecialties required for American College of Surgeons level I trauma center verification. We sought to assess the rates and patterns of emergent operative VS consultation compared with other surgical subspecialties in the trauma setting. METHODS: A retrospective analysis was performed on all patients who presented with traumatic injuries requiring emergent surgical operations (<3 hours after presentation) from 2015 to 2019 at a level I trauma center. Patient demographics, injury characteristics, and data on consulted surgical subspecialties were collected. The primary outcome measured was the rate of intraoperative consultation to VS and other subspecialties (OS). RESULTS: A total of 2265 patients were identified, with 221 emergent intraoperative consults to VS and 507 consults to OS. After VS (9.8%), the most common subspecialties consulted were orthopedics (9.2%) and urology (5%). Overall, VS was more likely to be consulted in immediate trauma operations (<1 hour after presentation) (65.6% vs 38.1%, P < .0001), penetrating injuries (73.3% vs 47.9%, P < .0001), and at night (60.6% vs 51.9%, P = .02) compared with OS. Time from admission to operation was shorter for cases when VS was involved compared with OS (54.1 ± 40.4 vs 80.6 ± 47.9 minutes, P < .0001). In a multivariable logistic regression model, we found that requiring an immediate operation was associated with higher odds of requiring an intraoperative vascular consult (odds ratio = 1.49, 95% confidence interval = 1.12-2.0). CONCLUSIONS: Vascular surgeons are consulted intraoperatively to assist with emergent trauma at a greater rate compared with specialties that are required for level I trauma center verification. Current American College of Surgeons verification processes and site-specific policies should be re-evaluated to consider VS coverage as a requirement for trauma center verification.

Apolipoprotein A-I, elevated in trauma patients, inhibits platelet activation and decreases clot strength.

Apolipoprotein A-I (ApoA-I) is elevated in the plasma of a subgroup of trauma patients with systemic hyperfibrinolysis. We hypothesize that apoA-I inhibits platelet activation and clot formation. The effects of apoA-I on human platelet activation and clot formation were assessed by whole blood thrombelastography (TEG), platelet aggregometry, P-selectin surface expression, microfluidic adhesion, and Akt phosphorylation. Mouse models of carotid artery thrombosis and pulmonary embolism were used to assess the effects of apoA-I in vivo. The ApoA-1 receptor was investigated with transgenic mice knockouts (KO) for the scavenger receptor class B member 1 (SR-BI). Compared to controls, exogenous human apoA-I inhibited arachidonic acid and collagen-mediated human and mouse platelet aggregation, decreased P-selectin surface expression and Akt activation, resulting in diminished clot strength and increased clot lysis by TEG. ApoA-I also decreased platelet aggregate size formed on a collagen surface under flow. In vivo, apoA-I delayed vessel occlusion in an arterial thrombosis model and conferred a survival advantage in a pulmonary embolism model. SR-BI KO mice significantly reduced apoA-I inhibition of platelet aggregation versus wild-type platelets. Exogenous human apoA-I inhibits platelet activation, decreases clot strength and stability, and protects mice from arterial and venous thrombosis via the SR-BI receptor.

Pre-existing Systolic Dysfunction is the Most Powerful Predictor of Failed Arteriovenous Fistula Maturation.

BACKGROUND: Patients requiring hemodialysis access creation often have significant comorbid conditions, which may impact access maturation. Underlying cardiac dysfunction likely plays an important role in the maturation of arteriovenous fistulae (AVF). The effect of specific parameters of cardiac function on successful AVF creation has not previously been explored. METHODS: A retrospective chart analysis of patients undergoing first-time AVF creation at a single center from 2011 to 2018 was performed. Patients with a transthoracic echocardiogram within the 12 months prior to surgery were included. Standard demographic and perioperative variables were collected, in addition to echocardiographic and vascular mapping data. The primary outcome was access maturation, defined as the use of the access site for hemodialysis at 3, 6, and 12 months after surgery. RESULTS: A total of 121 patients met inclusion criteria with a cumulative AVF maturation rate of 57% (69/121) in this select population. Patients with pre-existing systolic cardiac dysfunction were more than 5 times less likely to see their AVF mature by one year postsurgery (OR = 0.17, P = 0.018). Preoperative venous diameter, access site location, and the type of fistula did not differ significantly between patients with and without systolic dysfunction. Selection of the cephalic vein as the venous anastomosis and diastolic dysfunction (≥ Grade 2) were also associated with lower rates of access maturation, although these associations were less robust. CONCLUSIONS: Systolic cardiac dysfunction is the most important nonmodifiable variable associated with failed AVF maturation. Patients requiring hemodialysis with significant pre-existing cardiac dysfunction may not be appropriate for permanent access creation, and long-term catheter use should be seriously considered as an alternative.

Superior Mesenteric Artery and Vein Injuries: Operative Strategies and Outcomes.

Traumatic injuries to the mesenteric vessels are rare and often lethal. Visceral vessels, such as the superior mesenteric artery (SMA) and vein (SMV), supply blood to the small and large bowel by a rich system of collaterals. Because fewer than 100 such injuries have been described in the literature, they pose challenges in both diagnosis and management and can unfortunately result in high mortality rates. Prompt diagnosis, surgical intervention, and resuscitation can lead to improved outcomes. Here, we review the literature surrounding traumatic injuries of the SMA/SMV and discuss management strategies.

Female gender is associated with increased late luminal narrowing within the stent graft after thoracic endovascular aortic repair.

BACKGROUND: Luminal narrowing, suspected secondary to thrombus, occurs within stent grafts at an unclear incidence after thoracic endovascular aortic repair (TEVAR). The significance of this phenomenon has not been determined, nor have the risk factors for development of intragraft luminal narrowing. Small graft diameter is hypothesized to be a risk factor for the development of ingraft stenosis. METHODS: A retrospective analysis was performed of a multicenter healthcare system including all patients who underwent TEVAR between July 2011 and July 2019 with at least 1 year of subsequently available surveillance contrast-enhanced computed tomography imaging. Standard demographic, preoperative, intraoperative, and postoperative variables were collected. Measurements were obtained via direct off-line images from computed tomography scans. Patent intragraft diameters were compared with baseline and interval change values were normalized to time to follow-up. The primary outcome measure was annual rate of intragraft luminal narrowing. RESULTS: There were 208 patients who met the inclusion criteria (94 women, 114 men) with a median follow-up of 822 days. The mean annual rate of percent intragraft diameter reduction was 10.5 ± 7.7% for women and 7.6 ± 5.6% for men (P = .0026). Multivariate analysis demonstrated female gender (P = .0283), preoperative diagnosis of hypertension (P = .0449), and need for coverage of the left subclavian artery (P = .0328) were all significant predictors of intragraft luminal narrowing. Small aortic diameters were not found to be associated independently with ingraft luminal narrowing nor was the concomitant use of antiplatelet or anticoagulation medications. Significant amounts of ingraft luminal narrowing, defined as a greater than 20% intragraft diameter decrease, were associated with an increased need for any reintervention, including for malperfusion, endoleak, and symptomatic aneurysm (P = .0249). Kaplan-Meier estimates demonstrated a significant gender-associated difference in high rates of intragraft luminal narrowing (P = .00189). CONCLUSIONS: In this analysis, female gender is shown to be a significant nonmodifiable risk factor for intragraft luminal narrowing after TEVAR. The development of this phenomenon is not benign; as such, these findings were associated with an increased need for reintervention. This finding may be attributable to differences in aortic compliance or gender-associated differences in coagulation pathways and merits further investigation. Surveillance after thoracic stent grafting must account for patient-specific variations in complication risk.

Management and Outcomes after Upper Versus Lower Extremity Vascular Trauma.

BACKGROUND: While significant literature exists regarding peripheral vascular injury management, the vast majority focuses on lower extremity arterial injury. As a result, clinical management of arterial injury in the upper extremities is often guided by literature specific to lower extremity vessel injury. The purpose of this study is to use the largest series of patients reported in the literature to compare management and outcomes of upper and lower extremity traumatic vascular injuries. METHODS: Patients who underwent operative repair of traumatic vascular injuries of the extremities were identified from the trauma registry of a level I trauma center. A retrospective chart review (2011-2019) was conducted. Demographics, mechanism of injuries, operative techniques, and outcomes were compared between patients with upper versus lower extremity vascular injuries. RESULTS: Five hundred thirty-five patients were included with 234 (43.8%) patients undergoing repair of upper extremity vascular injuries. Patients with upper extremity vascular injuries were more likely to be female (16.7% vs. 9%, P = 0.007), have a pre-hospital tourniquet (21.8% vs. 12%,P = 0.002), have associated nerve injuries (40.2% vs. 4.7%, P < 0.0001) or present with bleeding (76.1% vs. 64.1%, P = 0.002) but were less commonly associated with concomitant fractures (25.6% vs. 39.9%, P = 0.0006). There was no difference in age, race, or mechanism of injury. In regards to operative management, upper extremity injuries were more likely to be managed with vessel ligation (38% vs. 17.6%, P < 0.0001) or primary reanastomosis (12.4% vs. 5.6%, P = 0.009) and were less frequently associated with concomitant fasciotomies (13.3% vs. 56.5%, P < 0.0001). Postoperatively, upper extremity injuries were associated with persistent nerve deficits (21.7% vs. 10%, P = 0.0002) while lower extremity injuries had a higher incidence of 30-day limb loss (5.7% vs. 1.3%, P = 0.008). There were no differences in mortality or graft-patency rates between groups. CONCLUSIONS: Upper extremity injuries are associated with a lower limb-loss rate but increased prevalence of neurological deficits after vascular trauma compared to lower extremities. A high level of suspicion is paramount to intraoperative identify associated nerve injuries to improve postoperative functional outcomes.

Stent Graft Oversizing is Associated with an Increased Risk of Long-Term Left Ventricular Wall Thickening in Young Patients Following Thoracic Endovascular Aortic Repair.

BACKGROUND: Left ventricular (LV) wall thickening occurs in patients following thoracic endovascular aortic repair (TEVAR). Clinical consequences of cardiovascular (CV) remodeling may be more significant younger patients with longer anticipated life spans. Risk factors for CV remodeling following TEVAR are unknown but may be related to graft size. METHODS: A retrospective analysis was performed of a multicenter healthcare system including patients aged ≤60 who underwent TEVAR between 2011 and 2019 with at least 1 year follow-up computed tomography angiography imaging available. Standard perioperative variables, native aortic diameter, and stent graft specifications were collected. Graft oversizing was calculated by dividing proximal graft diameter by proximal aortic diameter on preoperative imaging. Posterior LV wall thickness was measured at baseline and interval increases were normalized to time-to-follow-up. Primary outcome was annual rate of posterior LV wall thickening. RESULTS: One hundred one patients met inclusion criteria with a mean (SD) follow-up time of 1270 (693) days. Overall mean (SD) rate of LV wall thickness change was 0.534 (0.750) mm per year. Mean (SD) absolute LV wall thickness at most recent follow-up was 10.97 (2.85) mm for men, 9.69 (2.03) mm for women. Multivariate analysis demonstrated that higher rates of LV wall thickening were associated with narrower graft diameters (P = 0.0311). Greater absolute LV wall thickness at follow-up was associated with narrower grafts (P= 0.0155) and greater graft oversizing (P= 0.0376). Logistic regression demonstrated individuals who met criteria for LV hypertrophy were more likely to have narrower stent-grafts (P= 0.00798) and greater graft oversizing (P= 0.0315). CONCLUSIONS: LV wall thickening occurred to a greater degree in individuals with narrower stent-grafts and higher rates of graft oversizing. This has significant implications for long-term cardiovascular health in younger patients may undergo TEVAR for atypical indications. Particular attention should be paid to long-term effects of stent-graft oversizing when selecting grafts in such populations.

Intra-abdominal Inferior Vena Cava Injuries: Operative Strategies and Outcomes.

Visceral vascular injuries are relatively uncommon even in busy urban trauma centers. The inferior vena cava (IVC) is the most frequently injured visceral vein and can be a complex operative challenge. Despite advances in early volume resuscitation, improved transport times, prompt operative intervention, and hemorrhage control, mortality rates have remained largely unchanged. This article conducts an in-depth review of the literature surrounding IVC injuries and a detailed discussion of operative strategies and management as survivability is ultimately dependent on the grade of injury, location, and the presence of hemorrhagic shock.

Influence of baseline kidney dysfunction on perioperative renal outcomes after endovascular aneurysm repair with suprarenal fixation.

BACKGROUND: Conflicting evidence exists regarding the comparative effects of endovascular aneurysm repair (EVAR) with and without suprarenal fixation. We compare outcomes in patients treated by EVAR with baseline normal kidney function and moderate and severe chronic kidney disease. METHODS: Patients with normal kidney function (glomerular filtration rate [GFR] ≥60 mL/min/1.73 m2) or moderate (GFR = 30-59 mL/min/1.73 m2) or severe (GFR <30 mL/min/1.73 m2) kidney disease who underwent EVAR (N = 5534) were identified from the American College of Surgeons National Surgical Quality Improvement Program targeted database (2011-2015). Groups were determined by the presence (Cook Zenith [Cook Medical, Bloomington, Ind] or Medtronic Endurant [Medtronic, Minneapolis, Minn]) or absence (Gore Excluder [W. L. Gore & Associates, Flagstaff, Ariz]) of a suprarenal fixation system. Postoperative renal complications, defined as rise in creatinine concentration of >2 mg/dL without dialysis or new dialysis requirements, were analyzed within the first 30 days with results stratified by degree of kidney disease. RESULTS: A total of 5534 patients underwent EVAR, with 3225 (58.3%) receiving a device using a suprarenal fixation system. Suprarenal fixation systems were less commonly used for symptomatic patients (11.0% vs 13.7%; P = .002) and patients with ruptured abdominal aortic aneurysm (4.5% vs 6.3%; P = .01). There was no difference in baseline kidney function between groups. EVAR with suprarenal fixation was associated with more renal complications (1.40% vs 0.65%; P = .008). In subgroup analysis, patients with moderate kidney dysfunction (n = 1780) had more renal complications (2.2% vs 0.8%; P = .02) with suprarenal fixation systems. No differences were seen in patients with normal kidney function (0.4% vs 0.2%; P = .32; n = 3597) or severe kidney dysfunction (14.3% vs 10.2%; P = .45; n = 157). This difference was driven mostly by postoperative elevation of creatinine concentration (0.6% vs 0.2%; P = .03) without requirements for new dialysis (0.8% vs 0.4%; P = .08). After adjustments with multivariate logistic regression models, EVAR with suprarenal fixation was associated with more renal complications (odds ratio, 2.65; 95% confidence interval, 1.32-5.34). CONCLUSIONS: In our study, EVAR with suprarenal fixation devices was associated with more perioperative renal complications in patients with moderate kidney dysfunction. Long-term evaluation of these patients undergoing EVAR should be considered.

Pharmacologic Therapy is Not Associated with Stroke Prevention in Patients with Isolated Blunt Vertebral Artery Injury.

BACKGROUND: Vertebral artery injury (VAI) is often grouped with carotid artery injury into a broader classification of blunt cerebrovascular injury, despite fundamental differences in mechanism of injury and outcome. This study seeks to evaluate the efficacy of medical therapy in preventing strokes for isolated VAI. METHODS: Patients with isolated blunt VAI (2011-2018) were identified from the trauma registry of a level I trauma center. A retrospective chart review was conducted excluding patients with concomitant carotid artery injury. Factors examined included demographics, injury characteristics, anatomic classification, and management strategy. Patients were stratified by whether they received pharmacological (antiplatelet or anticoagulation) therapy. The primary outcome was new posterior circulation stroke within 30 days of injury as confirmed by imaging studies. RESULTS: A total of 206 patients with blunt VAI were included. Median Injury Severity Score was 17 and 33 (16.0%) patients presented with Glasgow Coma Scale <8. The most common mechanism of injury was motor vehicle collision (58.7%). The injuries were bilateral in 38 (18.5%) patients and 73 (35.4%) suffered multisegmental injuries. The anatomic severity of injuries was Grade 1 = 38.8%, Grade 2 = 25.7%, Grade 3 = 4.9%, Grade 4 = 30.6%, and Grade 5 = 0.5%. There was no correlation between anatomic grade and stroke (P = 0.11) or initiation of pharmacologic therapy (P = 0.30). In total, 172 (84%) patients received pharmacological therapy with no differences in baseline characteristics between treated and untreated patients. Overall, the 30-day stroke rate was 1.9%. There was no difference in stroke rate between patients who received medical therapy versus those who did not (5.9% vs. 1.2%, P = 0.13). In subgroup analysis by injury severity, medical therapy did not improve stroke rates. Among patients treated with aspirin, there was no difference in stroke rate between doses of 81 vs. 325 mg (1.1% vs. 0%, P = 1). CONCLUSIONS: Isolated VAI is associated with a very low risk of stroke and treatment with medical therapies including antiplatelet or anticoagulation does not improve risk of stroke.

Traumatic Blunt Injuries to the Celiac Artery: A 5-Year Review From a Level I Trauma Center.

BACKGROUND: Injury to the celiac artery secondary to a blunt mechanism of trauma is an extremely rare injury that accounts for only 1%-2% of all visceral vascular lesions. Although rare, this injury is associated with significant mortality. Despite this high mortality, there are currently only a few published case series of blunt celiac artery injuries in the literature. This study sought to review all cases of blunt celiac artery injuries that presented to our Level I trauma center over a 5-year period. METHODS: This was a retrospective chart review of all patients who presented with a traumatic blunt celiac artery injury between January 2012 and March 2017. RESULTS: A total of 10 patients met the inclusion criteria for this study. The majority of patients were male (7/10, 70%), the average age was 38.3 ± 16.1 years, and overall mortality was 20% (2/10). On average, patients spent 10.2 ± 6.5 days in the hospital, 4.4 ± 4.5 days in the ICU, and 1.6 ± 2.0 days on the ventilator. The majority of patients presented with either an intimal dissection (3/10, 30%) or an intraluminal thrombus (3/10, 30%). Other injuries included pseudoaneurysms (2/10, 20%), complete avulsion (1/10, 10%), and an intimal dissection with thrombus (1/10, 10%). Of these injuries, 2 (20%) were noted to have retrograde flow on imaging studies including computed tomography angiography and a visceral angiogram. The majority of patients (8/10, 80%) were managed nonoperatively, and 5 (50%) patients were discharged home on aspirin. One patient who was initially managed nonoperatively required an unplanned return to the operating room for ischemic bowel, liver, and stomach. There were no other complications noted. DISCUSSION: Traumatic blunt injury to the celiac artery is rare. Although there are multiple treatment options, there is currently no consensus in regard to management guidelines. In this case series, the majority of patients were successfully managed nonoperatively suggesting that a selective approach for intervention on patients with a blunt celiac artery injury should be considered.

Suprageniculate Approach to Release of Popliteal Entrapment without Distal Bypass Despite Preoperative Runoff Thrombosis.

BACKGROUND: Popliteal artery entrapment syndrome is an uncommon condition in which anatomic or functional popliteal artery compression causes arterial insufficiency. We present a case of popliteal entrapment with runoff thrombosis treated with suprageniculate release of entrapment without distal bypass. RESULTS: A 15-year old boy with Klinefelter syndrome presented with right leg claudication severely limiting his activity. He had a palpable femoral pulse, but no palpable popliteal or foot pulses on the right. Noninvasive testing showed a partially thrombosed popliteal artery with an ankle-brachial index (ABI) of 0.69. Computed tomography scan revealed type III popliteal entrapment with distal thromboses and abnormal insertion of gastrocnemius muscle. Popliteal entrapment release was performed via a medial suprageniculate approach in consideration for distal bypass. The soleus was released first; intraoperative angiography showed continued popliteal compression with forced dorsiflexion. This was followed by release of the gastrocnemius and found caudal and medial to the soleus as a tight band. Repeat angiography showed cessation of popliteal artery compression with dorsiflexion. Bypass was not performed due to improvement of distal flow seen on angiography. Postoperative recovery was unremarkable. On 1-month and 9-month follow-up, he had a normal ABI and arterial duplex, was asymptomatic, and had returned to normal activities. CONCLUSIONS: We describe suprageniculate approach to popliteal release that may be useful if a distal bypass is planned. In this case, bypass was unnecessary despite the abnormal appearance of distal runoff on preoperative imaging, as the child's perfusion improved with entrapment release alone, and arterial remodeling over time resulted in normal perfusion and arterial appearance on duplex imaging.

Thrombelastographic pattern recognition in renal disease and trauma.

BACKGROUND: Thrombelastography (TEG) is a viscoelastic hemostatic assay. We have observed that end-stage renal disease (ESRD) and trauma-induced coagulopathy (TIC) produce distinctive TEG tracings. We hypothesized that rigorously definable TEG patterns could discriminate between healthy controls and patients with ESRD and TIC. METHODS: TEG was performed on blood from ESRD patients (n = 54) and blood from trauma patients requiring a massive blood transfusion (n = 16). Plots of independent TEG parameters were analyzed for patterns coupled to disease state, compared with controls. Decision trees for taxonomic classification were then built using the "R-Project" statistical software. RESULTS: Minimally overlapping clusters of TEG results were observed for the three patient groups when coordinate pairs of maximum amplitude (MA) and TEG-activated clotting time (ACT) were plotted on orthogonal axes. Based on these groupings, a taxonomical classification tree was constructed using MA and TEG ACT. Branch points were set at an ACT of 103 s, and these branches subdivided for MA at 60.8 mm for the high ACT branch and 72.6 mm for the low ACT branch, providing a correct classification rate of 93.4%. CONCLUSIONS: ESRD and TIC demonstrate distinct TEG patterns. The coagulopathy of ESRD is typified by a prolonged enzymatic phase of clot formation, with normal-to-elevated final clot strength. Conversely, TIC is typified by prolonged clot formation and weakened clot strength. Our taxonomic categorization constitutes a rigorous system for the algorithmic interpretation of TEG based on cluster analysis. This will form the basis for clinical decision support software for viscoelastic hemostatic assays.