Reinhard Pamler

Initial experience with intentional stent-graft coverage of the subclavian artery during endovascular thoracic aortic repairs.

Purpose: To investigate the extent to which clinical status is affected by covering the left subclavian artery (LSA) with stent-grafts in the thoracic aorta. Methods: Stent-graft reconstruction of the thoracic aorta was performed in 23 patients (20 men; mean age 50.8 years, range 17–77) for management of rupture (n = 11), type B dissection (n = 9), or aneurysm (n = 3). All patients had bilaterally equal systolic and diastolic blood pressures (141.3 ± 19.8 and 78.9 ± 11.0 mmHg, respectively). Twenty Gore TAG and 1 Talent thoracic endografts were used; 2 cases required a combination of prostheses. In all patients, the stent-graft was intentionally placed to cover the LSA. Follow-up included clinical examination with blood pressure measurements and computed tomography during the first postoperative week and at 3-month intervals thereafter. Results: After coverage of the LSA by the stent-graft, systolic pressure fell by a mean 48.3 ± 23.4 mmHg. In 4 cases of proximal endoleak, however, systolic pressure fell by only 25.0 ± 15.0 mmHg. Twenty (78.5%) patients reported no complaints during a mean follow-up of 12.1 ± 7.3 months. Postinterventional complaints reported by 3 patients included exercise-dependent paresthesias; nonexercise-dependent, intermittent, and completely reversible dizziness; and a temperature difference between the upper extremities with no decrease in strength. Conclusions: Covering the LSA is generally well tolerated by patients and increases the landing zone for the placement of thoracic stent-grafts. Long-term studies, however, must investigate the hemodynamic effects of this procedure on the vertebrobasilar circulation.

Endovascular repair of traumatic descending aortic transection.

PURPOSE To present the results of endovascular repair of acute traumatic descending aortic transection. METHODS Among 66 thoracic stent-graft repairs performed between 1995 and 2001, 11 patients (9 men; mean age 34 years, range 12-73) underwent emergent endovascular repair of acute traumatic descending aortic transection following traffic accidents. Immediate treatment of aortic rupture was indicated in all patients because of a marked fresh hematoma with hemothorax; the spiral computed tomographic (CT) scans showed circular or semicircular descending thoracic aortic injuries. The devices used included 11 thoracic Excluders and 1 Talent stent-graft. RESULTS No patient required conversion to an open transthoracic operation. No patient developed temporary or permanent neurological deficit after endovascular treatment. Two type I endoleaks required periprocedural treatment: a second stent-graft was deployed in one and the existing stent-graft was balloon dilated in the other. Two patients underwent secondary procedures (iliac access complication and revascularization of the left subclavian artery). One patient died 22 days postoperatively secondary to injuries unrelated to the aortic repair. Over a mean 14-month follow-up (range 1-26), the surveillance CT scans have shown the stent-graft to be correctly positioned in all patients. CONCLUSIONS The treatment of acute traumatic descending aortic transection with an endovascular approach is feasible and safe and may offer the best means of therapy. Mortality and the risk of neurological deficit are low compared with open operations.

Complications after Endovascular Repair of Type B Aortic Dissection

Purpose: To outline the complications encountered after endoluminal treatment in patients with type B aortic dissection. Methods: Between 1999 and 2001, 14 patients (12 men; mean age 60.3 years, range 39–79) with isolated type B aortic dissection (13 chronic, 1 acute) underwent aortic stent-grafting. Three patients with chronic dissection presented an acute clinical picture and were managed emergently. The left subclavian artery was intentionally covered by the prosthesis in 9 patients. Follow-up studies were performed at 6-month intervals. Results: Stent-graft implantation was technically successful in all patients, but incomplete sealing (endoleak) of the entry site required additional proximal stent-graft implantation in 4. The left subclavian artery remained patent in 5 patients. Secondary conversion was required in 3 patients: 2 for acute type A dissection resulting from injury to the aortic arch by Talent endografts and a sustained hemorrhage (left hemothorax). In another patient, a secondary intramural hematoma subsided spontaneously. Anterior spinal artery syndrome in 1 patient persisted at 1 month. No bypass was necessary for the 9 patients with the covered left subclavian arteries. Mean follow-up was 14 months (range 1–23). Conclusions: Stent-grafting is feasible in patients with type B aortic dissection, although it is associated with a considerable rate of complications. Frank reporting of these sequelae for a variety of stent-grafts is of paramount importance to clarifying the limitations of the method.

Endovascular Interventions on Persistent Sciatic Arteries

Purpose: To report our experience with interventional procedures used to treat complete and incomplete persistent sciatic arteries (PSA). Case Reports: Three female patients with PSAs displayed varying symptoms referable to this rare anatomical variant. In the first woman, a 1-year history of intermittent lower limb ischemia and an acute event prompted angiography, which demonstrated proximal occlusion of 2 crural vessels and a partially thrombosed sciatic artery aneurysm. To prevent further embolism, the aneurysm was excluded with a stent-graft. Endograft patency and aneurysm exclusion have been maintained up to 22 months. In a 41-year-old diabetic with chronic limb ischemia and digital gangrene, a flow-limiting stenosis of the sciatic artery was stented, restoring adequate pedal perfusion. The stent remained patent at the 18-month follow-up. The third patient suffered from a tumor-related pelvic hemorrhage originating from retrograde perfusion through the PSA, which had been ligated during previous surgery. Attempted embolization via a collateral connection between the incomplete PSA and the popliteal artery failed, and the patient died. Conclusions: Vasculopathies involving the sciatic artery are uncommon but may be amenable to interventional techniques, such as coil embolization and stent implantation. PSA aneurysm exclusion with a stent-graft may represent a new therapeutic alternative to standard surgery that obviates potential sciatic nerve damage, but the durability of the repair remains to be determined.

Endovascular grafting of traumatic aortic aneurysms in contaminated fields.

PURPOSE To evaluate the potential of endovascular stent-grafts to treat traumatic aortic lesions in contaminated areas. METHODS Four patients (3 women; ages 26-78 years) underwent stent-grafting to repair an aortic rupture sustained in a motorcycle accident, aortic lacerations secondary to surgical treatment of spondylitis in 2 patients, and an aortobronchial fistula following surgical thoracic aortic repair 10 years earlier. Stent-grafts (2 Corvita, 1 Talent, and 1 Vanguard) were placed endoluminally into the infected areas via a transfemoral approach. Follow-up included erythrocyte sedimentation rate, white blood count, C-reactive protein, blood cultures, and computed tomography (CT). RESULTS The stent-grafts were successfully placed in all cases and excluded the aortic lesion. Under supportive antibiotic therapy, inflammation parameters returned to normal. CT imaging showed no evidence of paraprosthetic infection, nor were there any other complications over a follow-up that ranged from 3 to 34 months. CONCLUSIONS Endovascular therapy may be an alternative in the acute management of aortic ruptures in the setting of infection. Long-term results are required for definitive evaluation of the method.

Geometric Changes in Aortic Endografts over a 2-Year Observation Period

Purpose: To report geometric changes in bifurcated aortic endografts observed over a 2-year follow-up period. Methods: Twenty-two patients (21 men; mean age 68 years, range 57–83) with abdominal aortic aneurysms were treated with an endovascular stent-graft. Follow-up examinations included spiral computed tomographic scanning postoperatively and at 3, 6, 9, 12, 18, and 24 months after treatment. Geometric changes were measured using 3-dimensional reconstructed images in anteroposterior (AP) and lateral projections. Locations for the measurements were the proximal neck, the midportion of the endograft, and the graft limbs at the origin of the iliac arteries. Results: Lateral changes predominated, demonstrating maximum angles on the side of the inserted left limb. For the proximal neck, the stent angle changed by a mean −0.71° in the AP and 4.0° in the lateral projection. At the midgraft, changes were −0.56° for AP and 12.5° for lateral. The right limb showed an angle of 6.43° in AP and −0.43° in lateral, whereas the left limb angles changed 1.38° in AP and 11.71° in the lateral plane after 2 years. There was no statistically significance difference in these changes from baseline. Conclusions: Aortic endografts are exposed to a significant amount of movement after insertion, but the resultant changes are very inhomogeneous, unpredictable, and ongoing even after 2 years. The most vulnerable location seems to be the attachment zone of the modular graft limb. These geometric changes might be one cause for late complications, including leaks and limb dislocations.

Transesophageal Echocardiographic Guidance of Thoracic Aortic Stent-Graft Implantation

Purpose: To evaluate the efficacy of intraoperative transesophageal echocardiography (TEE) as an adjunctive measure in guiding the implantation of endoluminal stent-grafts in the thoracic aorta. Methods: TEE was used in 21 of 30 patients (27 men; median age 70 years; range 19–77) undergoing implantation of Excluder or Talent stent-grafts for management of 11 type B aortic dissections, 7 thoracic aortic aneurysms, 2 traumatic thoracic aortic ruptures, and an aortic coarctation. We evaluated the ability of TEE to provide evidence of (1) correct placement of the guidewire within the true lumen, (2) reduction in blood flow in the false lumen following stent deployment, and (3) early complications. Results: Definite identification of the true lumen and a reliable evaluation of the position of the stent-graft guidewire during advancement were possible in all patients. Reduction of blood flow within the false lumen following deployment of the stent-graft was visualized in >70% of patients with aortic dissection. In the patient with aortic coarctation, TEE recognized the acute onset of aortic dissection following stent dilation, which resulted in immediate management with an additional stent. Conclusions: The intraoperative use of TEE in the implantation of stent-grafts in the thoracic aorta is not significantly invasive and is easily employed. It permits excellent evaluation of the correct placement of the stent guidewire and, in patients with aortic dissection, intraoperatively visualizes effective blood flow reduction in the false lumen following stent-graft deployment. Its ability to recognize early complications may indicate the need for additional maneuvers during the surgical procedure.

Thromboembolic Complications after Endovascular Aortic Aneurysm Repair

PURPOSE To evaluate the frequency and significance of thromboembolic complications following endovascular treatment of aortic aneurysms. METHODS One hundred seventy-four patients (153 men; mean 71.4 years, range 26-90) underwent endovascular repair of aneurysms of the thoracic (n = 38) or abdominal (n = 136) aorta using a variety of endografts. All patients were examined preprocedurally using 3-phase helical computed tomography (CT) to determine appropriate endograft size. To exclude the occurrence of infarction in parenchymal organs, the first postprocedural CT scan was compared with preoperative findings. Newly recognized perfusion deficits were taken as evidence of procedure-related infarction. RESULTS Infarctions were detected in 16 (9.2%) patients: 13 in the kidneys, 2 in the spleen, with 1 in the mesentery; only the mesenteric infarction was clinically symptomatic. Both splenic infarctions were associated with deployment of stent-grafts in the thoracic aorta (5.3% of the 38 patients), while the mesenteric and 13 renal infarctions were seen in patients with infrarenal abdominal aortic aneurysms (0.7% and 9.6%, respectively, of 136 patients). One patient experienced complete thromboembolic occlusion of a renal artery, which was partially recanalized with intraoperative lysis. CONCLUSIONS Thromboembolic complications of endovascular aortic aneurysm repairs are not uncommon, and although usually asymptomatic, these sequelae have the potential to be life threatening. Perfusion abnormalities may respond to immediate lytic therapy with complete dissolution of the thrombus in certain isolated cases.

Magnetic resonance imaging versus multislice computed tomography of thoracic aortic endografts.

Purpose: To compare the potential of magnetic resonance imaging (MRI) to multislice computed tomography (CT) for evaluating stent-graft placement in the thoracic aorta. Methods: Susceptibility artifacts in 2 different stent-graft systems (Talent and Excluder) were evaluated in vitro in 2 angulations (straight and 33° curved) using 3 different MRI gradient echo sequences (True FISP, 2-dimensional FLASH, and 3-dimensional Turbo FLASH). The size of the stent-related artifact was measured, and the relative stent lumen was calculated. In vivo stent demarcation, stent patency, and additional findings were determined in 13 patients (3 Talent, 9 Excluder, and 1 combined) and compared to CT findings. Results: In vitro, both endograft systems proved to be MR compatible, with the relative stent lumen value ranging from 82% to 100% in the straight configuration; in a curved model, the relative stent lumen value ranged from 56% to 92% with the 3D Turbo FLASH sequence, which provided the smallest susceptibility artifacts. The Excluder endoprosthesis caused significant signal inhomogeneity within the stent in a curved configuration. In vivo, MRI and multislice CT showed similar results, with CT imaging slightly superior in stent demarcation and MRI better in demonstrating thrombus. CT beam hardening artifacts were pronounced in the Talent system, while the Excluder device caused significant signal inhomogeneity within the stent on magnetic resonance angiography. Conclusions: Multislice CT and contrast-enhanced MRI are fast, reliable means of providing all relevant information for surveillance of fully MR-compatible stent-grafts in the thoracic aorta.

Does Successful Embolization of Endoleaks Lead to Aneurysm Sac Shrinkage

PURPOSE To determine whether embolization of endoleaks after endovascular repair of aortic aneurysms is associated with a decrease in the diameter of the aneurysm. METHODS Fifteen patients (13 men; median age 76 years) demonstrated primary endoleaks persisting > or =3 months after endovascular abdominal aortic aneurysm repair with a variety of commercial endografts. In 8 patients, coil embolization failed to completely obliterate the leak, whereas embolotherapy proved successful in the remaining 7 patients. Surveillance of endoleaks and the effect of their embolization on aneurysm size were followed with serial computed tomographic (CT) scans. Follow-up after embolization extended for at least 12 months. RESULTS Patients with persistent leak exhibited a slight increase in mean aneurysm area from 21.41+/-4.25 to 22.47+/-6.70 cm2. Medians differed from 20.03 (range 16.59-28.73) to 23.03 (range 14.14-33.69) cm2 (p = 0.0078, 95% confidence interval [CI] = 0.0075 to 0.0081). Successfully treated patients, however, showed a mean decrease from 20.58+/-3.63 (median 19.87) to 16.36+/-6.46 cm2 (median 18.10) at 1 year (p = 0.0156, 95% CI = 0.0151 to 0.0160). The medians differed significantly between groups (p < 0.05). CONCLUSIONS Persistent endoleaks after endovascular aortic aneurysm treatment led to an increase in the diameter of the aneurysm, whereas complete occlusion was associated with a significant decrease in aneurysm diameter.