Massimo Napolitano

Outcomes of Ultrasonic Accelerated Thrombolysis for Inferior Vena Cava Thrombosis

Objectives: The clinical experiences and outcomes of ultrasonic accelerated transcatheter thrombolytic therapy for symptomatic inferior vena cava (IVC) thrombosis have not been widely reported. We describe our experience with the EkoSonic Endovascular System (EKOS Corporation, Bothell, Wash) for endovascular management of caval thrombosis. Methods: All patients diagnosed with symptomatic IVC thrombosis who were treated with EKOS from March 2008 to March 2014 were included for review. Data of the patients including clinical presentation, thromboembolic risk factors, treatment details, initial and follow-up imaging, and clinical outcomes were recorded. Results: Sixteen patients (eight male, eight female; mean age, 58 years) presented with acute symptomatic IVC thrombosis. Risk factors for thromboembolism included malignant disease (four), recent surgery (three), trauma (three), inherited hypercoagulability (three), obesity (seven), and smoking (two). Twelve patients had previous deep venous thrombosis (DVT), and 11 of these patients had IVC filters in situ. Ultrasound imaging revealed bilateral proximal DVT on presentation in eight patients; the remaining eight presented with unilateral DVT. All patients were treated with systemic anticoagulation, limb elevation, and compression. The indication for thrombolysis was phlegmasia in two patients and persistence of significant symptoms in 14 patients. Confirmation of caval thrombosis was by contrast venography before EKOS treatment. Ultrasound-guided access was through the popliteal vein in 11 patients (three bilateral), greater saphenous vein in one patient, and common femoral vein in four patients (three bilateral). EKOS catheters were placed with the working length extending from the distal extent of the thrombus in the extremity to patent IVC. Administration of tissue plasminogen activator through the EKOS catheter and heparin through the sheath was given for an average of 24 hours (range, 12-48 hours), with follow-up venography performed after exchange of the thrombolysis catheter. Adjunctive mechanical thrombectomy was performed in 14 patients. There were no complications. At median follow-up of 13 months (range, 1-41 months), all but one patient had improvement or complete resolution of symptoms. Two patients had recurrent lower extremity DVT (one after warfarin held for lumbar puncture, one after knee replacement). Conclusions: This is the largest reported series of ultrasonic accelerated thrombolysis for acute IVC thrombosis. These results suggest that this modality may be helpful in treating patients with significant symptoms without significant complication.

Epidemiology of Lower Extremity Deep Venous Thrombosis in Critically Ill Adolescents

Objective To determine the epidemiology of lower extremity deep venous thrombosis (DVT) in critically ill adolescents, which currently is unclear. Study design We performed a multicenter, prospective, cohort study. Adolescents aged 13‐17 years who were admitted to 6 pediatric intensive care units and were anticipated to receive cardiopulmonary support for at least 48 hours were eligible, unless they were admitted with DVT or pulmonary embolism or were receiving or anticipated to receive therapeutic anticoagulation. While patients were in the unit, serial sonograms of the lower extremities were performed, then centrally adjudicated. Bayesian statistics were used to leverage the similarities between adults and adolescents. Results A total of 88 adolescents were enrolled, from whom 184 lower extremity sonograms were performed. Of these, 9 adolescents developed DVT, with 1 having bilateral DVT. The frequency of DVT was 12.4% (95% credible interval: 6.1%, 20.1%), which ranged from 6.3% to 19.8% with a variability of 41.0% across units. All cases of DVT occurred in adolescents who received invasive mechanical ventilation (frequency: 16.5%; 95% credible interval 8.1%, 26.6%). DVT was associated with femoral central venous catheterization (OR 15.44; 95% credible interval 1.62, 69.05) and severe illness (OR for every 0.1 increase in risk of mortality 3.11; 95% credible interval 1.19, 6.85). DVT appears to be associated with prolonged days on support. Conclusions Our findings highlight the similarities and differences in the epidemiology of DVT between adults and adolescents. They support the conduct and inform the design of a trial of pharmacologic prophylaxis in critically ill adolescents.

Balloon angioplasty for symptomatic inferior vena cava aneurysm

Aneurysms of the inferior vena cava (IVC) are uncommon. Symptomatic patients usually present with thrombosis and venous obstruction. Classification is based on location and the presence or absence of congenital IVC interruption. Treatment options include observation, open surgical resection, and endovascular modalities, of which coil embolization and stent graft placement have previously been described. We report the case of a patient with a 5.0-cm infrarenal IVC aneurysm and associated congenital stenosis who successfully underwent balloon angioplasty. Whereas management should be determined on an individual basis, balloon angioplasty is a plausible treatment for IVC aneurysms in the setting of congenital stenosis.

TCT-805 Use of Orbital Atherectomy to Aid in Endovascular Aortic Endograft Delivery in Patients with Severe Iliac Artery Occlusive Disease

Stent grafts for repair of abdominal aortic aneurysms are continuing to evolve to lower profile designs to facilitate easier endograft delivery. Despite improvements in design, a subset of patients undergoing endovascular abdominal aortic aneurysm repair (EVAR) exist with severely calcified iliac

Anti–Factor Xa Assay—A Changing Standard for Venous Thromboprophylaxis?

Venous thromboembolism (VTE) represents a significant public health concern and is the leading cause of preventable deaths in hospitalized patients. The Agency for Healthcare Research and Quality has identified this topic as a top 10 public safety concern to be addressed.1 As with other VTE investigations, lower extremity deep vein thrombosis (DVT) serves as a surrogate for fatal pulmonary embolism. Trauma patients are a uniquely vulnerable population. Low-molecular-weight heparin at a standard dosage of 30 mg twice daily is an accepted standard for prophylaxis. Ko et al2 and other investigators3,4 have questioned this approach, reporting plasma levels below that recommended for effective prophylaxis when measuring anti–factor Xa (anti-Xa). Ko and colleagues propose a dosing strategy for lowmolecular-weight heparin prophylaxis guided by anti-Xa trough levels. Compared with historical controls, the study group had a decrease in VTE. However, the reduction in VTE was predominantly a reduction in infrapopliteal thrombi. In this small study, the 2 groups were enrolled in consecutive periods. Were there background differences that could affect the outcome reported? Ultrasonography to identify VTE was requested only for symptomatic patients. Could the threshold for requesting this have varied between individual clinicians? Could the accuracy of the vascular laboratory findings for diagnosis of infrapopliteal DVT have been different in different years? Management of infrapopliteal DVT remains controversial, especially as a surrogate for pulmonary embolism. Given the price of the assay, the cost-effectiveness of testing prophylactic doses of enoxaparin sodium remains an issue. With greater use, the cost has decreased to

Adjunctive Use of Thoracic Stent Cuffs to Treat Infrarenal Aortic Necks Too Large for Standard EVAR

25 per assay from the

Distal True Lumen Compression After Thoracic Endovascular Repair for Aortic Dissection Treated With Endovascular Fenestration

41 quoted by Ko and colleagues. Identifying patients at higher risk, such as those with elevated creatinine clearance, will be useful in guiding future investigations. Dose adjustment is conventionally monitored by measuring peak anti-Xa levels.5 However, these investigators chose to measure trough levels, suggesting that they may better correlate with DVT. Another trauma study measured both peak and trough levels but reported a poor correlation between the two.4 Supporting the strategy by Ko and colleagues, Malinoski et al3 reported a significant correlation between low trough levels and increased risk of proximal DVT. The anti-Xa assay is gaining wider use for monitoring heparin and enoxaparin anticoagulation. We are currently using the anti-Xa assay for monitoring therapeutic heparin dosages, resulting in decreased variability and more accurate dosing adjustment. Compared with heparin, enoxaparin has more predictable bioavailability. Titrating doses to anti-Xa levels could decrease the risk of VTE, but the best method for measuring these levels and the clinical significance of dose adjustment have yet to be established. While gaining accuracy, expense and availability continue to be concerns when considering wider adoption of this assay.

VH08. Surgical Repair of a Retropancreatic Portal Vein Aneurysm With Pancreatic Preservation

Objectives: To evaluate early outcomes and short-term durability of thoracic stent cuffs in patients with abdominal aortic aneurysms (AAA) and infrarenal necks too large for standard endovascular aneurysm repair (EVAR) who were symptomatic, not suitable for open surgery, and could not wait for a custom fenestrated device to be created. Methods: From July 2010 to December 2012, 13 patients with juxtaor pararenal AAA underwent endovascular repair with thoracic aortic endografts as proximal aortic cuffs in conjunction with standard EVAR devices. The patients were symptomatic and were deemed unfit for open surgery due to severe cardiopulmonary and/or renal comorbidities. All patients had infrarenal neck diameters greater than the indications for use for standard aortic endografts. Primary end points were technical success (as defined by aneurysm exclusion without endoleak), follow-up aneurysm exclusion by computed tomographic angiogram, and 30-day and longterm mortality. Results: Thirteen patients (10 men, 3 women) with a mean age of 77.1 years underwent EVAR who presented with symptomatic juxtaor pararenal abdominal aortic aneurysms. The mean aneurysm size was 7.2 cm, and the mean infrarenal aortic neck diameter was 35.5 mm measured by centerline analysis. Technical success was achieved in 100% of cases. The 30-day mortality was 8% (one of 13 patients). At a mean follow-up of 524 days, there have been no endoleaks or other aneurysm related mortalities. There was one death due to stroke at 605 days postop. Conclusions: Complex endovascular repair of juxta and pararenal AAA using thoracic stents cuffs can be safely and successfully performed in symptomatic patients medically unfit for open repair. Using thoracic stent cuffs below the visceral vessels may reduce the complexity and possibly the risk of repair when compared with fenestrated endografts. These techniques can be used for urgent and emergent cases where the wait time for fenestrated technology is prohibitive. Although our results have demonstrated short-term success, long-term durability of this technique with further evaluation is required.