Erin H. Murphy

Endovascular Repair of Acute Traumatic Thoracic Aortic Transection with Laser-Assisted In-Situ Fenestration of a Stent-Graft Covering the Left Subclavian Artery

Purpose: To report the use of in-situ laser-assisted endograft fenestration during thoracic endovascular aortic repair (TEVAR). Case Report: A healthy 26-year-old man presented to the emergency department after sustaining blunt chest trauma. He was hemodynamically stable, although he subjectively complained of tearing chest pain and pleuritic chest wall pain. Radiography revealed a left clavicular fracture, multiple rib fractures, and a widened mediastinum. Imaging showed a partially contained acute aortic transection just distal to the takeoff of the left subclavian artery (LSA); the arch had a bovine configuration, with a shared origin of the right innominate and left common carotid arteries. Endovascular repair was elected, but to avoid sacrificing the LSA, TEVAR with in-situ graft fenestration was performed to reduce the risk of posterior circulation stroke, spinal cord ischemia, and subclavian steal syndrome. A Talent thoracic stent-graft was deployed, with the covered portion of the endograft extending just distal to the shared origin of the innominate and left carotid arteries. A laser catheter was advanced through the LSA to fenestrate the endograft; the fenestration was dilated and stented with an iCast stent, which was flared proximally and distally to effect a seal. At 6 weeks, imaging documented that the repair was patent and secure; the patient continues to do well at his most recent follow-up at 8 months. Conclusion: This technique may provide a means for extending thoracic endografting technology to a greater number of patients with acute thoracic aortic pathology.

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.

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.

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.

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.

Device-specific aneurysm sac morphology after endovascular aneurysm repair: Evaluation of contemporary graft materials

OBJECTIVE This study analyzed device-specific aneurysm sac morphology after endovascular aneurysm repair (EVAR) with low-permeability devices. METHODS Between September 2004 and May 2006, 122 patients were treated with EVAR. Three different devices were implanted: 47 Zenith (Cook, Indianapolis, Ind), 46 AneuRx (Medtronic, Santa Rosa, Calif) with Resilient Dacron Graft Material, and 29 Excluder (W. L. Gore & Associates, Flagstaff, Ariz) with low-porosity polytetrafluoroethylene (PTFE). Patients were followed up at 1, 6, and 12 months and then biannually with computed tomography (CT) angiography. Standard axial two-dimensional CT measurements were obtained and compared with preoperative imaging. The preoperative scan served as a baseline, and the minor axis diameter, measured at the largest axial cut of the abdominal aortic aneurysm, was compared with the same measurement at follow-up. RESULTS Patient age, sex, and preoperative aneurysm morphology were similar among groups. Patients receiving the Zenith endograft had a significantly larger neck diameter; however, there was no difference in the neck length between groups. The rate of type II endoleaks was similar for the Zenith (17%), AneuRx (17%), and Excluder (14%). At 1, 6, 12, and 18 months, all three grafts were associated with sac shrinkage. The resulting decreases in mean aneurysm size at 18 months and corresponding shrinkage were Zenith, 11%, 6.4 +/- 1.8 mm; AneuRx, 18.9%, 12.7 +/- 2.7 mm; and the Excluder, 5.5%, 3.3 +/- 0.9 (P < .05). The sac size in the 19 patients with a type II endoleak decreased 8.06% compared with a 15.43% decrease in sac size in patients without endoleak at 6 months. No significant sac expansion > or =5 mm has been observed among any of the groups to date. CONCLUSIONS Sac regression with all devices appears to have been favorably influenced by the new generation of graft materials and is improved compared with published reports of older generation graft materials for the AneuRx and Excluder. However, there is a trend toward greater sac regression with devices using Dacron vs PTFE. The relationship of aneurysm morphology and long-term effects on aortic stent grafts is yet to be determined.

Device-specific resistance to in vivo displacement of stent-grafts implanted with maximum iliac fixation.

Purpose: To compare the in vivo device-specific downward displacement force of various externally supported endografts implanted with maximum iliac fixation. Methods: Twenty female sheep had aneurysms created with a graft patch in the infrarenal aorta. In 12 animals, a fully supported modular bifurcated stent-graft [AneuRx (n=4), Talent (n=4), or Zenith (n=4)] was deployed; in the other 8, a bifurcated aortic graft was surgically anastomosed to the infrarenal aorta. All grafts were displaced in vivo by applying downward traction to a guidewire brought out both femoral arteries. The peak force to cause initial stent-graft migration or disruption of the sutured anastomosis was recorded and compared. Results: There was no difference in animal size, aortic neck diameter or length, aneurysm size, or iliac artery diameter for animals receiving the AneuRx, Talent, or Zenith stent-grafts and those undergoing surgical repair. The mean length of iliac fixation was 31.0±0.3 mm, 30.8±0.5 mm, and 31.3±0.6 mm for the AneuRx, Talent, and Zenith devices, respectively (p=NS). Peak force to initiate migration was 30.2=5.5 N (range 25–38) for the AneuRx, 44.8±5.5 N (range 40–53) for the Talent, 46.7±5.4 N (range 38–55) for the Zenith, and 40.6±7.5 N (range 31–50) for the surgical anastomosis (p=0.01). There was no difference detected in the peak force to initiate migration between the suprarenally affixed Talent and Zenith stent-grafts and the surgical anastomosis (p=0.55). Conclusion: Devices with a suprarenal component require significantly greater force to cause downward displacement compared to infrarenal devices. The force required to displace a suprarenal device with maximal iliac fixation was equivalent to the force required to disrupt a surgical anastomosis.

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.

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.

Technical tips for abdominal aortic endografting.

Favorable clinical results combined with increased patient demand for minimally invasive surgery has resulted in an increased application of endovascular aortic aneurysm repair (EVAR), and this treatment modality is now being extended to younger, healthier patients. While it seems that EVAR is becoming a desirable option for many patients, it is essential to realize that the feasibility of the procedure may be limited at times by patient anatomy and technical difficulties. Specific anatomical difficulties can be imposed by difficult access, short tortuous and calcified aortic and iliac landing zones, and presence of coincident complex iliac aneurysms. Renal failure has also presented a concern for patients being considered for treatment with EVAR, as the contrast loads required for the procedure, as well as for continued postoperative surveillance, may place the patient at risk. We will discuss technical maneuvers and considerations when encountering difficult anatomy and challenging surgical procedures.