Intravascular Ultrasound Use in Peripheral Arterial and Deep Venous Interventions: Multidisciplinary Expert Opinion From SCAI/AVF/AVLS/SIR/SVM/SVS.

Percutaneous revascularization is the primary strategy for treating lower extremity venous and arterial disease. Angiography is limited by its ability to accurately size vessels, precisely determine the degree of stenosis and length of lesions, characterize lesion morphology, or correctly diagnose postintervention complications. These limitations are overcome with use of intravascular ultrasound (IVUS). IVUS has demonstrated the ability to improve outcomes following percutaneous coronary intervention, and there is increasing evidence to support its benefits in the setting of peripheral vascular intervention. At this stage in its evolution, there remains a need to standardize the use and approach to peripheral vascular IVUS imaging. This manuscript represents considerations and consensus perspectives that emerged from a roundtable discussion including 15 physicians with expertise in interventional cardiology, interventional radiology, and vascular surgery, representing 6 cardiovascular specialty societies, held on February 3, 2023. The roundtable's aims were to assess the current state of lower extremity revascularization, identify knowledge gaps and need for evidence, and determine how IVUS can improve care and outcomes for patients with peripheral arterial and deep venous pathology.

Fatigue Test Method to Evaluate the 50 Year Durability of Venous Stents.

OBJECTIVE: Iliofemoral venous obstructive disease can result in significant, potentially debilitating symptoms that can negatively affect quality of life. Unlike arterial disease, patients with deep venous disease have a significantly lower median age, therefore the need for long term stent patency becomes a matter of decades rather than years. Furthermore, iliofemoral lesions frequently require stent placement across the inguinal ligament. Such stents are subject to dynamic stress from leg movement and associated concerns for device fatigue, resulting in stent fracture. The aim of this study was to describe an in vitro 50 year stent fatigue test method designed to assess durability against dynamic stress induced device fracture. METHODS: Through literature review, cadaver studies, and computer modelling, the most challenging loading was confirmed to be hip flexion across the inguinal ligament. This occurs when the patient adjusts between a seated and standing position. Sit to stand hip flexion at the inguinal ligament was effectively simulated on the bench in this in vitro experimental study. RESULTS: When tested under challenge parameters, hip flexion was reliably found to cause fractures in non-venous nitinol stents. However, a dedicated self expanding nitinol venous stent, engineered for improved durability, underwent up to 50 years of simulated loading on the bench with 15% (3/20) of stents experiencing fractures at 50 years, compared with fractures in 35% (14/40) of non-venous stents tested to 1.4 years; no statistical testing was performed as durations do not match and the objective was to demonstrate the test method. CONCLUSION: The presented fatigue test method is a suitable approach for evaluating the durability of stents intended for venous use. Venous stents demonstrated superior fatigue resistance compared with non-venous stents via in vitro hip flexion testing.

Variations and inconsistencies in venous ablation coverage policies between single-state and multistate carriers in the United States.

BACKGROUND: Vein ablation is a common and effective treatment for patients with chronic venous insufficiency. The overuse of vein ablation despite the existence of evidence-based guidelines has resulted in insurance companies developing restrictive policies for coverage that create barriers to appropriate care. This study compares the insurance coverage by single-state carriers (SSCs) and multistate carriers (MSCs), highlighting the variations and inconsistencies in the various policies. METHODS: The American Venous Forum Venous Policy Navigator was reviewed for the various policies available in the United States. The policies were divided into SSCs and MSCs. The characteristics of the policies, including the anatomic and hemodynamic criteria for specific veins, duration of conservative treatment, disease severity, symptoms, and types of procedures covered, were compared between the two groups. SAS, version 9.4 (SAS Institute Inc) was used for statistical analysis. RESULTS: A total of 122 policies were analyzed and divided between SSCs (n = 85; 69.7%) and MSCs (n = 37; 30.3%). A significant variation was found in the size requirement for great saphenous vein ablation. Although 48% of the policies did not specify a size criterion, the remaining policies indicated a minimal size, ranging from 3 to 5.5 mm. However, no significant differences were found between SSCs and MSCs. Similar findings were encountered for the small and anterior accessory saphenous veins. MSCs were more likely to define a saphenous reflux time >500 ms compared with SSCs (81.1% vs 58.8%; P = .04). A significant difference was found between the SSCs and MSCs in the criteria for perforator ablation in terms of size and reflux time. MSCs were significantly more likely to provide coverage for mechanochemical ablation than were SSCs (24.3% vs 8.2%; P = .03). SSCs were more likely to require ≥12 weeks of compression stocking therapy than were MSCs (76.5% vs 48.7%; P = .01). No significant differences were found in the clinical indications between the two groups; however, MSCs were more likely to mention major hemorrhage than were SSCs. CONCLUSIONS: The results of this study highlight the variations in policies for venous ablation, in particular, the striking inconsistencies in size criteria. MSCs were more likely to cover mechanochemical ablation and require a shorter duration of conservative therapy before intervention compared with SSCs. Evidence-based guidance is needed to develop more coherent policies for venous ablation coverage.

Consensus Statement on the Management of Nonthrombotic Iliac Vein Lesions From the VIVA Foundation, the American Venous Forum, and the American Vein and Lymphatic Society.

A nonthrombotic iliac vein lesion is defined as the extrinsic compression of the iliac vein. Symptoms of lower extremity chronic venous insufficiency or pelvic venous disease can develop secondary to nonthrombotic iliac vein lesion. Anatomic compression has been observed in both symptomatic and asymptomatic patients. Causative factors that lead to symptomatic manifestations remain unclear. To provide guidance for providers treating patients with nonthrombotic iliac vein lesion, the VIVA Foundation convened a multidisciplinary group of leaders in venous disease management with representatives from the American Venous Forum and the American Vein and Lymphatic Society. Consensus statements regarding nonthrombotic iliac vein lesions were drafted by the participants to address patient selection, imaging for diagnosis, technical considerations for stent placement, postprocedure management, and future research/educational needs.

Intravascular Ultrasound Use in Peripheral Arterial and Deep Venous Interventions: Multidisciplinary Expert Opinion From SCAI/AVF/AVLS/SIR/SVM/SVS.

Percutaneous revascularization is the primary strategy for treating lower extremity venous and arterial disease. Angiography is limited by its ability to accurately size vessels, precisely determine the degree of stenosis and length of lesions, characterize lesion morphology, or correctly diagnose postintervention complications. These limitations are overcome with use of intravascular ultrasound (IVUS). IVUS has demonstrated the ability to improve outcomes following percutaneous coronary intervention, and there is increasing evidence to support its benefits in the setting of peripheral vascular intervention. At this stage in its evolution, there remains a need to standardize the use and approach to peripheral vascular IVUS imaging. This manuscript represents considerations and consensus perspectives that emerged from a roundtable discussion including 15 physicians with expertise in interventional cardiology, interventional radiology, and vascular surgery, representing 6 cardiovascular specialty societies, held on February 3, 2023. The roundtable's aims were to assess the current state of lower extremity revascularization, identify knowledge gaps and need for evidence, and determine how IVUS can improve care and outcomes for patients with peripheral arterial and deep venous pathology.

The fate of untreated concomitant suprarenal aortic aneurysms after endovascular aneurysm repair of infrarenal aortic aneurysms.

OBJECTIVE: Many patients treated with endovascular aortic repair (EVAR) have a concomitant suprarenal abdominal aortic aneurysm (sAAA). The natural history of these sAAAs and whether they require intervention after EVAR is unknown. METHODS: We identified 470 patients from the M2S database (M2S Inc, West Lebanon, NH) as having an infrarenal AAA (iAAA) with a concomitant sAAA (diameter, 2.9-4.7 cm). The analysis included 217 patients with preoperative computed tomography angiography and follow-up imaging of ≥12 months. Patients who did not undergo EVAR (n = 65) served as a control. Patients with EVAR were subdivided into 90 with suprarenal fixation (SR) and 62 with infrarenal fixation (IR). Standard measurements from the M2S images were extracted, and growth rates were calculated for different abdominal aortic segments. RESULTS: The average follow-up was 33.0 ± 18.8 months. The average sAAA initial size and growth rate were 34.6 ± 3.0 and 0.6 ± 1.1 mm/y for SR, 34.0 ± 3.3 and 0.6 ± 1.3 mm/y for IR, and 36.6 ± 3.4 and 1.2 ± 1.5 mm/y for controls (SR vs IR, P > .05; SR or IR vs control, P < .05). After EVAR, two of 152 (1.3%) sAAAs grew to ≥ 50 mm, which was not statistically different from four of 65 (6.2%) in the control group (P = .07). At 48 months, the Kaplan-Meier freedom from sAAA growth to ≥ 50 mm was 99.3% for patients undergoing EVAR and 95.2% for controls (P = .061). Patients with starting sAAAs sized ≥ 40 mm had a higher growth rate (1.4 ± 2.1 mm/y) and frequency of growth to ≥50 mm (14.3%) than patients with starting sAAAs sized <40 mm (0.7 ± 1.2 mm/y and 1.5%; P < .05). CONCLUSIONS: Isolated treatment of iAAAs via EVAR with a concomitant sAAA is acceptable because endografts with or without SR do not affect sAAA growth rates. Routine EVAR follow-up is sufficient for sAAAs of <40 mm, and more intensive follow-up should be considered for sAAAs of 40 to 50 mm. For sAAAs approaching 50 mm, an endograft with IR should be considered in case sAAA repair is required in the future.

The management of endograft infections following endovascular thoracic and abdominal aneurysm repair.

OBJECTIVE: The management of infected aortic endografts is a challenging endeavor. Treatment of this problem has not been well defined as it is fairly uncommon. However, the incidence is increasing. This study examines the results of treatment at a single center for this morbid process. METHODS: A retrospective review was performed of patients treated for infected abdominal or thoracic endograft infection following previous abdominal or thoracic endovascular aneurysm repair. Data was reviewed for patient demographics, details of initial endograft implantation, presentation and timeline of subsequent infection, management of infected grafts, and outcomes during follow-up. RESULTS: Overall, 18 patients were treated for infected endografts (thoracic: six, abdominal:12). Three patients were treated between 2000 and 2006, corresponding to a 0.6% institutional incidence of endograft infection (3/473). There were no transfers for infected endografts from outside institutions. From 2006 to 2011, 15 patients underwent treatment. Six were institutional cases of infections (6/945, 0.6% infection rate), however, there was an increase in transfers (n = 9). Median time to presentation with infection from endograft implant was 90 days, with over one-half (61%) presenting within the first 3 months. Tissue and/or blood cultures were positive in 12/16 growing Escherichia coli (n = 1), group A streptococcus (n = 3), methicillin-resistant Staphylococcus aureus (n = 3), or polymicrobial infections (n = 7). The other four patients were culture negative with computed tomography evidence of gas surrounding the endograft and clinical sepsis. Ten patients (abdominal: eight, thoracic: two) were treated with endograft explantation. The remaining eight patients were considered too high-risk for explant or refused open surgery and were therefore managed conservatively without explant (abdominal: four, thoracic: four). At a mean follow-up of 24.7 months, aneurysm-related mortality was 38.9% (n = 7) and was higher for patients presenting with aortoenteric or aortobronchial fistulas (n = 6/10, 60%) (P = .04) and for thoracic stent infections (n = 5/6; 83%) (P = .03). The only survivor of a thoracic infection was managed surgically. Overall survival for patients with abdominal endografts (n = 12) was similar between the eight patients managed surgically (n = 6/8; 75%) and the four selected for medical management (n = 4/4; 100%) (P = .39). All survivors remain on long-term suppressive antibiotics. Two additional patients died of unrelated causes during follow-up. CONCLUSIONS: Endograft infection is a rare but increasing complication after abdominal or thoracic endovascular aneurysm repair, which carries significant associated morbidity and mortality. Most endograft infections occurred in proximity to other types of infection, suggesting that bacterial seeding of the endograft was the source. Aortoenteric and aortobronchial fistulas are common presentations, which portend a significantly worse prognosis. Thoracic endograft infections, which have the highest rate of fistulization, have the worst outcomes. Surgical excision continues to be standard of care but conservative management with intravenous antibiotics may be of benefit in certain patients with abdominal endograft infections.

Incidence, predictors, and outcomes of hemodynamic instability following carotid angioplasty and stenting.

OBJECTIVE: To explore the incidence, predictors, and outcomes of hemodynamic instability (HI) following carotid angioplasty and stenting (CAS). METHODS: We retrospectively evaluated data on 257 CAS procedures performed in 245 patients from 2002 to 2011 at a single institution. The presence of periprocedural HI, as defined by hypertension (systolic blood pressure >160 mm Hg), hypotension (systolic blood pressure <90 mm Hg), and/or bradycardia (heart rate <60 beats per minute), was recorded. Clinically significant HI (CS-HI) was defined as periprocedural HI lasting greater than 1 hour in total duration. Logistic regression was used to analyze the role of multiple demographic, clinical, and procedural variables. RESULTS: Mean age was 70.9 ± 9.9 years (67% male). HI occurred following 84% (n = 216) of procedures. The incidence of hypertension, hypotension, and bradycardia was 54%, 31%, and 60%, respectively. Sixty-three percent of cases involved CS-HI. Recent stroke was an independent risk factor for the development of CS-HI (odds ratio, 5.24; confidence interval, 1.28-21.51; P = .02), whereas baseline chronic obstructive pulmonary disease was protective against CS-HI (odds ratio, 0.34; confidence interval, 0.15-0.80; P = .01). Patients with CS-HI were more likely to experience periprocedural stroke compared to other patients (8% vs 1%; P = .03). There were no significant differences in the incidence of mortality or other major complications between those with and without CS-HI. CONCLUSIONS: HI represents a common occurrence following CAS. While the presence of periprocedural HI alone did not portend a worse clinical outcome, CS-HI was associated with increased risk of stroke. Expeditious intervention to prevent and manage CS-HI is of critical importance in order to minimize adverse clinical events following CAS.

Effect of ethnicity and insurance type on the outcome of open thoracic aortic aneurysm repair.

OBJECTIVES: Mortality and complication rates for open thoracic aortic aneurysm repair have declined but remain high. The purpose of this study is to determine the influence of ethnicity and insurance type on procedure selection and outcome after open thoracic aneurysm repair. METHODS: Using the Nationwide Inpatient Sample database, ethnicity and insurance type were evaluated against the outcome variables of mortality and major complications associated with open thoracic aneurysm repair. The potential cofounders of age, gender, urgency of operation, and Deyo index of comorbidities were controlled. RESULTS: Between 2001 and 2005, a total of 10,557 patients were identified who underwent elective open thoracic aneurysm repair, with a significantly greater proportion of white patients (n = 8524) compared with black patients (n = 819), Hispanic patients (n = 556), and patients categorized as other (n = 658). Most patients (67%) were male. Almost half (45%) of the procedures were performed for urgent/emergent indications. Overall mortality was 10.7% (n = 1126) and the rate of spinal cord ischemia was 0.4% (n = 43). Univariate analysis revealed significant differences among race with regard to surgery type, income, hospital region, hospital bed size, and insurance type (P < 0.0001). Differences between insurance coverage were significant for gender, surgery type, income, hospital region, and race (P < 0.0001). Bivariate analysis by race revealed differences for death (P < 0.0001), pneumonia (P < 0.0001), renal complications (P = 0.011), implant complications (P < 0.0001), temporary tracheostomy (P = 0.004), transfusion (P < 0.0001), and intubation (P < 0.0001). In terms of payer status, bivariate analysis by insurance coverage revealed differences in death (P < 0.0001), central nervous system complications (P = 0.008), pneumonia (P < 0.0001), myocardial infarction (P = 0.001), infection (P < 0.0001), renal complications (P < 0.0001), malnutrition (P < 0.0001), temporary tracheostomy (P < 0.0001), spinal cord ischemia (P = 0.001), transfusion (P < 0.0001), and intubation (P < 0.0001). CONCLUSIONS: A high percentage of open thoracic procedures (45%) are performed urgently or emergently in the United States, which is associated with increased morbidity and mortality. Both ethnicity and payer status were associated with significant differences in surgical outcomes, including mortality and frequency of complications after open thoracic aortic aneurysm repair.

Venous compression syndromes in females: A descriptive review.

Venous compression syndromes have been described, yet the role of sex is poorly understood. Although iliac vein compression has been discussed more often with the advent of newer technologies, research has fallen short on defining epidemiology, best practices for evaluation and treatment, and differences in responses to treatment between men and females. The authors report on iliac vein compression, nonthrombotic renal vein compression, and other venous compression syndromes in females. Literature searches of PubMed were performed using the following keywords: females/females and May Thurner, venous stenting, venous outcomes, deep venous disease, deep venous compression, venous stenting, renal vein compression, renal vein surgery/stent, popliteal vein entrapment, venous thoracic vein entrapment, and popliteal vein entrapment. The articles prompted the authors to research further as the referenced articles were reviewed. Sex representation has not been addressed adequately in the research of venous compression syndromes, making the discussion of best treatment options and long-term outcomes difficult. More specific understanding of epidemiology and response to interventions will only come from research that addresses these issues directly, understanding that some of these syndromes occur rarely.

Thoracic endovascular repair (TEVAR) in the management of aortic arch pathology.

BACKGROUND: Conventional repair of aortic arch pathology is associated with significant mortality and stroke rates of 6-20% and 12%, respectively. Because endografting has excellent results for descending thoracic aortic disease, extension of thoracic endovascular repair (TEVAR) to the arch is a consideration. METHODS: Records of patients with aortic arch pathology treated with TEVAR were reviewed. Branch vessels were (1) covered without revascularization, (2) surgically bypassed, (3) stented, or (4) fenestrated. Technical success was defined both by accurate endograft deployment with disease exclusion and by target vessel revascularization. Patient postoperative outcomes, complications, and follow-up are reported. RESULTS: Between March 2006 and January 2010, 58 patients with arch pathology were treated with TEVAR. Indications included aneurysm (n = 19, 32.8%), dissection (type A: n = 3, 5.2%; type B: n = 18, 31.0%), transection (n = 8, 13.8%), pseudoaneurysm (n = 6, 10.3%), or other (n = 4, 6.9%). Pathology was zone 0 (n = 1, 1.7%), zone 1 (n = 10, 17.2%), zone 2 (n = 45, 77.6%), or zone 3 (n = 2, 3.4%). Interventions were emergent in 44.8% and elective in 55.2%. The left subclavian (LSA) was covered in all and revascularized (n = 23, 39.7%) via bypass (n = 13, 22.4%), stenting (n = 4, 6.9%), or fenestration (n = 6, 10.3%). The carotid was revascularized (n = 11, 19.0%) with bypass (n = 7, 12.1%) or stenting (n = 4, 6.9%). One patient (1.7%) underwent innominate revascularization with a homemade branched endograft. Technical success was 100% for endograft deployment and 97.1% for revascularization. Thirty-day mortality was 3.4% (2 of 58). ICU and hospital stays were 5.8 ± 6.8 (range: 0-34; median 4) and 10.9 ± 8.0 (range: 1-40; median: 9) days, respectively. Morbidities included renal failure (n = 3, 5.2%), respiratory (n = 2, 3.4%), myocardial infarction (n = 1, 1.7%), stroke (n = 6, 10.3%), and spinal cord ischemia (SCI) (n = 2, 3.4%). SCI (p < 0.001), but not stroke (p = 0.33), was associated with LSA sacrifice. Stroke was associated with underlying pathology and graft selection (p = 0.01). During follow-up of 10.6 ± 9.1 (range: 0-43) months, 17 patients (29.3%) required 20 reinterventions for endoleak (n = 8, 13.8%), disease extension (n = 5, 8.6%), steal (n = 4, 6.9%), or other reasons (n = 3, 5.2%). Dissection patients had a higher rate of reintervention (p = 0.01). All patients with steal had LSA sacrifice and were left-hand dominant. CONCLUSIONS: TEVAR can effectively treat aortic arch pathology in high-risk patients with low morbidity and mortality. TEVAR and branch vessel revascularization techniques may be extended to the more proximal arch without increased complications compared with patients with subclavian only involvement. Stroke remains the most significant drawback of arch interventions. Indications for intervention, graft selection, and revascularization choices may all affect outcome. LSA sacrifice is associated with increased SCI and may predispose left-handed patients to symptomatic weakness.

The effects of operative indication and urgency of intervention on patient outcomes after thoracic aortic endografting.

BACKGROUND: Endovascular repair for complex thoracic aortic pathology has emerged over the past decade as an alternative to open surgical repair. Reports suggest lower morbidity and mortality rates associated with endovascular interventions. The purpose of this report was to analyze a large single institution experience in endovascular thoracic aortic repair based on clinical presentation as well as within and outside specific instructions for use. METHODS: Records of all patients undergoing thoracic aortic endografting at our institution were retrospectively reviewed for demographics, interventional indications and acuity, operative details, and clinical outcomes. Study outcomes were analyzed by clinical presentation (urgent/emergent vs elective) and aneurysm morphology that was within and outside specific instructions for use as recommended by the manufacturer. RESULTS: Between March 2006 and October 2009, 96 patients underwent thoracic endografting for aneurysm (n = 43), transection (n = 7), penetrating ulcer (n = 11), dissection (n = 19; acute = 9, chronic = 10), pseudoaneurysm (n = 11), or miscellaneous indications (n = 5). Endografting was performed with various endografts (Gore TAG: 59; Medtrontic Talent: 26; Zenith-TX2: 7; Combination: 4.Involvement of the arch (n = 42, 43.75%) was treated with subclavian artery coverage without revascularization in 13 (13.5%), debranching in 20 (20.8%), and fenestration/stenting in 9 (9.38%). Involvement of the visceral vessels (n = 24, 25%) was treated with debranching in 15 (15.6%) or fenestration/stenting in 9 (9.4%). Patients had a mean follow-up of 11.5 ± 10.96 (range: 0-38) months. Overall mortality was 6.25% (n = 6). Mean intensive care unit stay was 6.26 ± 8.55 (range: 1-63, median: 4) days, and hospital stay was 9.97 ± 10.31 (range: 1-65, median: 65) days. Major complications were infrequent and included: spinal cord ischemia (n = 6, 6.25%), stroke (n = 6, 6.25%), myocardial infarction (n = 3, 3.15%), renal failure (n = 6, 6.25%), and wound complications (n = 9, 9.38%). Reoperation was required in 13 (13.54%), with early intervention in 2 (2.1%). The vast majority of patients were discharged directly to home (n = 66, 68.8%). There were no significant differences between death (1/49 [2%] vs 5/47 [10.6%], P = .07), stroke (3/49 [6%] vs 3/47 [6%], P = 1.0), or spinal cord ischemia (3/49 [6%] vs 3/47 [6%], P = 1.0) when comparing urgent/emergent presentation to elective cases, respectively. However, there were significant differences in death (6/58 [10.5%] vs 0/38 [0%], P = .04) and spinal cord ischemia (6/58 [10.5%] vs 0/38 [0%], P = .04) but not stroke (5/58 [8.8%] vs 1/38 [2.5%], P = .24] when procedures were performed outside the specific instructions for use. CONCLUSIONS: Results of this single-institution report suggest that endovascular thoracic aortic repair is a safe and effective treatment option for a variety of thoracic pathology including both elective and emergent cases. However, off-label usage of the devices is associated with a significantly higher risk of mortality and spinal cord ischemia, but the risk still appears acceptable given the majority of cases were emergent.

Volumetric analysis of type B aortic dissections treated with thoracic endovascular aortic repair.

BACKGROUND: Type B aortic dissections are being successfully treated by thoracic endovascular aortic repair (TEVAR). Postoperative false lumen patency has been associated with aneurysmal dilatation and rupture of the thoracic aorta, necessitating further intervention. This is the first volumetric analysis of type B aortic dissections comparing patients with and without false lumen thrombosis (FLT) after TEVAR. We hypothesized that a greater increase in postoperative true lumen volume will lead to FLT, and without this change, false lumen patency will result. METHODS: Preoperative and postoperative computed tomography angiography (CTA) imaging was analyzed using three-dimensional reconstruction to measure the short- and long-axis diameter and cross-sectional area of the true lumen, false lumen, and total aorta. Measurements were taken at 5-cm intervals from the left subclavian artery to the aortic bifurcation. Pre- and postoperative volumetric data were calculated and compared in patients with and without postoperative FLT. RESULTS: Between 2006 and 2010, 132 patients underwent thoracic aortic stent grafting. Of these, 31 (23%) had thoracic endografting for type B aortic dissection. Pre- and postoperative CTA images were available for analysis in 23 patients with a mean age of 59 ± 14 years treated for acute, complicated (n = 8, 35%), and chronic (n = 15, 65%) indications. Mean follow-up imaging was 9 months (range, 1-39 months). Thirteen patients (56%) had postoperative FLT and 10 (43%) had persistent false lumen patency. The dissections involved the left subclavian artery (n = 12), visceral arteries (n = 14), renal arteries (n = 16), and iliac arteries (n = 15). The left subclavian artery was intentionally covered in 15 patients (65%). There were no significant differences in age, acute vs chronic dissection, branch vessel involvement, coverage of the left subclavian artery, or distal extent of the endograft between patients with and without postoperative FLT. Patients with postoperative FLT had a significantly smaller preoperative maximum thoracic aortic diameter (5.05 ± 1.0 vs 6.30 ± 1.4 cm; P = .02). Volumetric analysis demonstrated significantly smaller preoperative true lumen volume (141.3 ± 68 vs 230.5 ± 92 cm(3); P = .01) in patients with FLT, but no difference in preoperative false lumen volume. Patients with FLT had a significant increase in the volume percentage of the true lumen from 42.7% to 61.7% (P = .02) after stent graft repair, compared with an increase from 46.7% to 47.7% (P = .75) in patients with persistent false lumen patency. CONCLUSIONS: This volumetric study of type B aortic dissection treated with TEVAR suggests that the ability of the endograft to significantly increase the true lumen volume as a percent of the total aorta most accurately predicts postoperative FLT. This is best demonstrated in a nonaneurysmal dissection regardless of timing since dissection.

Technique for branched thoracic stent-graft repair of a chronic type a aortic dissection in a patient with multiple prior sternotomies.

PURPOSE: To present a technique for endovascular treatment of a type A aortic dissection in a patient with multiple prior sternotomies and multiple medical comorbidities. TECHNIQUE: The method is illustrated in a 76-year-old man with a history of hypertension, hyperlipidemia, coronary artery disease, and open repair of a type A aortic dissection via a median sternotomy. The latter procedure was complicated by a pericardial effusion requiring drainage and sternal re-wiring. The diameter of the residual type A dissection beginning just distal to the aortic root had increased by 1.5 cm over 1 year, indicating the need for further intervention. To avoid redo sternotomy, a hybrid endovascular approach was planned, but it would require landing the stent in the ascending aortic arch, thus mandating branch vessel revascularization. Prior to stent-graft deployment, right-to-left carotid-carotid and left carotid-subclavian artery bypasses were performed with 8-mm polytetrafluoroethylene grafts. Three Talent grafts were deployed from the celiac artery to the left subclavian artery. A pre-wired homemade branched Talent stent-graft (34×34×115 mm) was used to revascularize the innominate artery and secure the arch. Transvenous ventricular pacing was used to improve deployment accuracy. A 10×38-mm iCast stent was placed through the branch and extended into the innominate artery. The subclavian artery was occluded with 2 Amplatzer plugs. Postoperative computed tomography demonstrated excellent proximal fixation, a widely patent branched graft to the innominate artery, and thrombosis of the aneurysmal false lumen. CONCLUSION: Treatment of type A dissections remains a difficult surgical challenge. The approach taken should be tailored for each patient. We successfully employed a combination of available minimally invasive techniques to treat a patient who was not ideally suited to any of the individual strategies.

In vitro analysis of type II endoleaks and aneurysm sac pressurization on longitudinal stent-graft displacement.

PURPOSE: To evaluate the effects of type II endoleaks and sac pressurization on stent-graft displacement following endovascular aneurysm repair (EVAR). METHODS: Experimental silicone infrarenal aneurysm (6-cm) models were "treated" with a Talent stent-graft deployed with 20-mm proximal and distal landing zones. Inflow and outflow vessels were created as part of the silicone model to control flow into the aneurysm sac. All aneurysm models were uniform, with a diameter neck of 31 mm, a neck length of 20 mm, and iliac artery diameters of 16 mm. The aortic model was secured in a water bath to a pulsatile pump under physiological conditions; the output phase ratio (%systole/%diastole) was set at 65/35 with a pump rate of 80 beats per minute. Commercially available bifurcated stent-grafts were then displaced in vitro utilizing a linear motion apparatus attached to a force gauge. The mean arterial pressure (MAP) and pulse pressure (PP) at the aortic inflow were 60.1 ± 3.1 and 38.3 ± 7.8 mmHg, respectively. Peak force to cause initial stent-graft migration with and without a type II endoleak was recorded and compared. RESULTS: In aneurysm sacs with no endoleak, the MAP and sac PP were 32 ± 6.4 and 6 ± 1.3 mmHg, respectively (p<0.01). In aneurysm sacs with a type II endoleak, the MAP and sac PP were 54.1 ± 9.7 and 16.1 ± 4.1 mmHg, respectively (p<0.02). Peak force to initiate migration was 16.0 ± 1.41 N (range 15-18) with no endoleak vs. 23.2 ± 2.2 N (range 20-25) in those with a type IIa endoleak and 23.5 ± 2.5 N (range 20-26) in those with a type IIb endoleak (p<0.001). CONCLUSION: Type II endoleaks are associated with a significantly increased sac pressure. Increased sac pressurization from type II endoleaks results in a significantly greater force to displace a stent-graft longitudinally. Type II endoleaks may therefore inhibit migration and offer a benefit following EVAR; however, clinical correlation of these results is required.

Effects of ethnicity and insurance status on outcomes after thoracic endoluminal aortic aneurysm repair (TEVAR).

BACKGROUND: Thoracic endoluminal aortic aneurysm repair (TEVAR) is associated with improved outcomes compared with open thoracic aortic aneurysm repair. This study was designed to better characterize TEVAR outcomes in a large population, and to determine if outcomes are independently influenced by patient ethnicity and insurance status. METHODS: Using the Nationwide Inpatient Sample (NIS) database, we selected patients who underwent TEVAR between 2001 and 2005. Ethnicity and insurance type were independently evaluated against the outcome variables of mortality and postoperative complications. Age, gender, hospital region, hospital location, hospital size, and comorbidities were controlled as cofounders. RESULTS: Between 2001 and 2005, 875 patients underwent TEVAR. There was a significantly greater proportion of Caucasians (n = 650) compared with African Americans (n = 104) or Hispanics (n = 49). Patients had a male preponderance, and most procedures were elective. The overall mortality was 13.3% (n = 117), and spinal cord ischemia was 0.8% (n = 7), with no differences between patients of varied ethnicity or payer status. Significant differences were noted among the races including gender (P = .003), income (P < .0001), hospital region (P < .001), hospital bed size (P = .013), and insurance type (P < .001). Significant variations in demographics characteristics were also present between patients with different insurance classifications including gender (P < .001), surgery type (P = .009), income (P = .003), race (P < .0001), and comorbidity index (P < .0001). After adjustment for cofounders and multiple comparisons, there were no differences in rates of complications among patients with varying race or insurance status. CONCLUSIONS: Mortality after TEVAR remains high in the US, although this may be associated with its early introduction during the study period. Nonetheless, the incidence of spinal cord ischemia is very low. Ethnicity and insurance type do not appear to influence TEVAR outcomes.

Device and imaging-specific volumetric analysis of clot lysis after percutaneous mechanical thrombectomy for iliofemoral DVT.

PURPOSE: To determine the most accurate method of assessing clot lysis after percutaneous mechanical thrombectomy for iliofemoral deep vein thrombosis (DVT) and to evaluate the effectiveness of two different pharmacomechanical thrombectomy devices. METHODS: Between 2004 and 2009, 33 patients (18 women; mean age 47 years) with iliofemoral DVT underwent pharmacomechanical thrombectomy using the AngioJet (n = 18) or Trellis (n = 15) devices with 10 mg of tenecteplase. Intravascular ultrasound (IVUS) and venography were performed over the iliofemoral segments before and after treatment. Cross-sectional vessel and lumen diameters were measured from the IVUS scans and the post-procedure anteroposterior and lateral venograms at 3 points (proximal, mid-section, and distal) along each iliofemoral vein by 2 independent observers blinded to the treatment method. Volumes of the recanalized segments were calculated and compared to volumes of the original venous segments to assess clot lysis with each PMT device. IVUS scans and venograms were also compared for their ability to identify residual lesions or clot in need of treatment. Repeatability between and among observers was analyzed using the Bland and Altman method. RESULTS: All procedures were successfully completed; there were only 2 minor bleeding complications. The mean volume of the recanalized segment was 2255+/-66 mm(3) by IVUS, representing 80% lysis of the clot compared to what was perceived as >90% lysis with venography (p<0.05). IVUS was able to delineate significant residual thrombus, stenosis, or May-Thurner anatomy requiring ancillary interventions in 100% of patients versus 48% (16/33) on the venograms (p<0.01). Quantitative assessments of the diameters of the involved venous segments from the venograms and IVUS were consistent between and among observers. Comparing the similar patient subgroups, AngioJet resulted in greater clot lysis (88%) versus the Trellis device (72%; p<0.01), corresponding to recanalized venous segment volumes of 2486+/-74 and 2025+/-57 mm(3) and total venous segment volumes of 2826+/-84 and 2813+/-79 mm(3), respectively. CONCLUSION: IVUS is superior to venography for detection of residual thrombus and underlying venous pathology after pharmacomechanical thrombectomy. While greater clot lysis was seen with the AngioJet system, both the AngioJet and Trellis devices resulted in excellent clinical clot lysis.

Open surgical repair after failed endovascular aneurysm repair: is endograft removal necessary?

INTRODUCTION: Open surgical repair after failed endovascular aneurysm repair (EVAR) usually involves complete endograft removal and replacement with a prosthetic surgical graft. This is associated with significant morbidity and mortality. We have used an alternative strategy focused on limiting the magnitude of surgical repair by preserving the functioning portion of the endograft and avoiding aortic cross-clamping, when possible. METHODS: Between January 2000 and 2008, patients requiring delayed conversion after EVAR at our institution were managed with (1) complete endograft preservation and external wrap of the aortic neck to secure a proximal seal, or (2) partial endograft removal with interposition grafting from the infrarenal aortic neck to the remaining endograft. Records of all patients were retrospectively reviewed for demographics, operative details, and outcomes. RESULTS: During this time, 12 patients were treated with delayed open surgical conversion. The indication for conversion in all patients was a type I endoleak with aneurysm enlargement not amendable to percutaneous intervention. Mean age was 81 +/- 6.2 years (range, 61-90 years). Average time to conversion was 44.7 months (range, 7-80 months). Complete endograft preservation was attempted in eight patients and was successful in six (75%). The two patients that failed this approach, as well as four additional patients who were not candidates for this approach, underwent partial endograft excision and replacement with an interposition graft sutured to the remaining portion of the stent graft. Complete endograft removal was not required in any patients. There was one post-operative mortality (8.3%) and one significant post-operative morbidity (8.3%). Mean intensive care unit and hospital stays were 2.8 +/- 3.9 days (range, 1-15 days) and 8.4 +/- 5.8 days (range, 3-26 days), respectively. CONCLUSIONS: Open surgical repair of failed EVAR can be accomplished with preservation of all or a significant portion of the endograft in most patients. This may limit the magnitude of the repair procedure and may reduce morbidity and mortality.

Symptomatic ileofemoral DVT after onset of oral contraceptive use in women with previously undiagnosed May-Thurner Syndrome.

OBJECTIVE: May-Thurner syndrome is characterized by left common iliac obstruction secondary to compression of the left iliac vein by the right common iliac artery against the fifth-lumbar vertebra. This anatomic variant results in an increased incidence of left-sided deep venous thrombosis (DVT). Furthermore, while a preponderance of left-sided DVT has been demonstrated in women during pregnancy and oral contraceptive use, patients are not typically screened for this condition after developing a left-sided DVT. As anticoagulation alone is ineffective for DVT treatment in the setting of May-Thurner anatomy, more aggressive treatment is warranted. Failure to diagnosis this condition predisposes these women to the unnecessary risks of recurrent DVT and post-thrombotic syndrome. METHODS: We present the occurrence of 7 adolescent patients with previously undiagnosed May-Thurner syndrome who presented with DVT after the initiation of oral contraceptive steroids (OCP) use. All 7 patients elected to proceed with mechanical thrombolysis/catheter based thrombolysis followed by endovascular stenting and were postoperatively treated with 6 months of warfarin. RESULTS: Mean patient age was 18.3 +/- 3.3 years (range, 16-24 years). Mean time to presentation after initiation of OCP was 5 weeks (range, 2-10 weeks). Mean time to intervention was 16.8 days (range, 10-24 days). All patients were treated with mechanical thrombectomy. Our rate of intraoperative clot resolution was 100%. All 7 patients were treated with self expanding nitinol stents after angioplasty of the iliac vein stenosis with resolution of the stenotic segment. Primary stent patency is 100% (7/7). Mean follow-up time is 13 +/- 13.84 months (range, 6-42 months). There have been no long-term complications related to surgical treatment or anticoagulation. All 7 patients have experienced resolution of left leg swelling and pain and have no evidence of post-thrombotic syndrome or DVT recurrence to date. CONCLUSIONS: Women on OCPs presenting with left-sided iliofemoral DVT should be screened for hypercoagulable disorders and underlying May-Thurner anatomy. Treatment of May-Thurner syndrome should include thrombolysis/thrombectomy and anticoagulation for current DVT in addition to angioplasty and stenting of the underlying obstruction.

Volume associated dynamic geometry and spatial orientation of the inferior vena cava.

BACKGROUND: The geometry and dynamics of the vena cava are poorly understood and current knowledge is largely based on qualitative data. The purpose of this study is to quantitate the dimensional changes that occur in the infrarenal inferior vena cava (IVC), in response to changes in intravascular volume. METHODS: IVC dimensions were measured at 1 cm and 5 cm below the renal veins, on serial contrasted computed tomographic (CT) scans, in 30 severely injured trauma patients during hypovolemic (admission) and fluid resuscitated (follow-up) states. Changes in volume of the infrarenal segment were calculated and correlated with changes in IVC diameter and orientation. The orientation of the infrarenal caval segment was quantified as the angulation of the major axis from the horizontal. A representation of the IVC diameter, as would be seen on standard anterior-posterior venographic imaging, was determined by projecting the CT image of the major axis onto a coronal plane. CT representations of venographic diameters were compared with measurements of the true major axis to assess accuracy of venograms for caval sizing and filter selection. RESULTS: All patients had evidence of a collapsed IVC (<15 mm minor axis dimension) on admission. Mean time between admission and follow-up CT was 49.5 (range: 1-202) days. The volume of the infrarenal segment increased more than twofold with resuscitation, increasing from 6.9 +/- 2.2 (range: 3.1-12.4) mL on admission, to 15.7 +/- 5.0 (range: 9.2-28.5) mL on follow-up (P < .01). At both 1 and 5 cm below the renal veins, the IVC expanded anisotropically such that the minor axis expanded up to five times its initial size accommodating 84% of the increased volume of the segment, while only small diameter changes were observed in the major axis accounting for less than 5% of the volume increase (P < .001). Further, the IVC was left-anterior-oblique in all patients, with the major axis 26 degrees off the horizontal on average. This orientation did not change significantly with volume resuscitation (P > 0.5). The obliquity of the IVC resulted in significant underestimation of caval size of up to 6.8 mm, when using the venographic representation for sizing instead of the true major axis (P < 0.001). CONCLUSIONS: In response to changes in intravascular volume, the IVC undergoes profound anisotropic dimensional changes, with greater displacement seen in the minor axis. In addition, the IVC is oriented left-anterior oblique and caval orientation is not altered by changes in volume status. IVC obliquity may result in underestimation of caval size by anterior-posterior venogram.