Cherrie Z. Abraham

Treatment of Aortic Arch Aneurysms with a Modular Transfemoral Multibranched Stent Graft: Initial Experience

OBJECTIVESnTo present initial experience with a new modular transfemoral multibranched stent graft for treating aortic arch aneurysms.nnnMETHODSnSix patients, considered high risk for open surgery, were treated with custom made branched stent grafts. All patients had a staged left carotid subclavian bypass before the endovascular procedure. Each branched graft had a 12 mm side branch for the innominate artery and an 8xa0mm side branch for the left common carotid artery.nnnRESULTSnFour patients out of six had uneventful placement of the prostheses, with successful exclusion of their aneurysms. One patient developed a type I endoleak that was managed successfully with coiling and gluing of the aneurysm sac. In one patient, cannulation of the innominate branch was unsuccessful and an extra-anatomic bypass was necessary to perfuse the right carotid and vertebral arteries. This patient developed a stroke, while one more suffered a right cerebellar infarct.nnnCONCLUSIONnWe have demonstrated the technical feasibility of a modular transfemoral branched stent graft for treatment of aortic arch aneurysms. The method is relatively safe based on initial experience. More cases and long-term follow up are necessary to evaluate the efficacy and safety of this new device.

Total endograft replacement of aortic arch

Total endovascular replacement of the aortic arch is a complex procedure that is often favoured when the pathology anatomy precludes a standard median sternotomy. Here we present the case of endograft repair in a 79 year old male with 6.5 cm arch aneurysm and 5.4 cm descending thoracoabdominal aneurysm. Following bilateral carotid-subclavian bypasses, a long 7 Fr sheath was advanced into the descending aorta through the common iliac artery purse string. A double curved long Lunderquist wire was guided to deep within the left ventricle, and the endograft carefully advanced over the wire. The graft was radiologically orientated, and deployed under asystolic conditions. Retrograde cannulation of the branches were accomplished, with carotid sheath placed into the branches followed by bridging stents. The graft delivery system was then removed. This approach obviates the need for a sternotomy, cumbersome extra-anatomic debranching, and hypothermic circulatory arrest.

RETRACTED: Treatment of aortic arch aneurysms with a modular transfemoral multibranched stent-graft: Initial experience

OBJECTIVEnTo present an initial experience with a new modular transfemoral multibranched stent-graft for treating aortic arch aneurysms.nnnMETHODSnSix patients, considered high risk for open surgery, were treated with a custom-made branched stent-graft. Two patients had aortic arch aneurysms, three had descending thoracic aortic aneurysms involving the distal arch, and one had a saccular aneurysm of the arch adjacent to the origin of the innominate artery. All patients had undergone a staged left carotid subclavian bypass before the endovascular procedure. Each branched graft had a 12-mm side branch for the innominate artery and an 8-mm side branch for the left common carotid artery. The branches were extended into their respective target arteries with covered self-expanding stents.nnnRESULTSnAneurysm exclusion without endoleak was successful in 5 of the 6 patients, and 11 of the 12 target vessels were successfully cannulated and preserved. Patient 1 developed a type I endoleak that was managed successfully with coiling and gluing of the aneurysm sac. Patients 2, 3, 5, and 6 had uneventful placement of the prostheses, with successful exclusion of the aneurysm sac. In patient 4, cannulation of the innominate branch was unsuccessful, and an extra-anatomic bypass was necessary to perfuse the right carotid and vertebral arteries.nnnCONCLUSIONSnWe have demonstrated the technical feasibility of a modular transfemoral branched stent-graft for treatment of aortic arch aneurysms. Our initial experience has shown that the method is relatively safe. Long-term follow-up is necessary to evaluate the efficacy and safety of this new device.

Sheath-shunt technique for avoiding lower limb ischemia during complex endovascular aneurysm repair

Complex aortic aneurysms are now being repaired by endovascular techniques, albeit with a potentially increased risk of lower limb ischemia-reperfusion injury. We report a simple technique to maintain perfusion to the lower limb during endovascular repair, using one additional introducer sheath placed antegrade, distal to the stent graft introduction site, and connected to the side arm of the working sheath in the contralateral artery. This allows continuous perfusion of the limb distal to the main stent graft introduction site. In our initial experience with 12 cases, with confirmed occlusion of the native arterial system by the stent graft introducer sheath, arterial occlusion time was 165 ± 84 minutes. Use of the sheath-shunt technique resulted in pulsatile flow in all cases, with an average flow of 42.2 ± 13.2 mL/min, and actual ischemia time was reduced to 14 ± 11 minutes. There were no complications related to the use of this technique. Given the limited risk of this technique coupled with a potential benefit, we propose its consideration in patients undergoing complex endovascular repair.

Cerebral embolic protection during endovascular arch replacement

Despite excellent results in high volume centers, open repair of aortic arch pathology is highly invasive, and can result in significant morbidity and mortality in high risk patients. Near-total and hybrid approaches to aortic arch disease states have emerged as an alternative for patients deemed moderate to high risk for conventional repair. Advantages of these approaches include avoidance of extracorporeal circulation and hypothermic circulatory arrest as well as avoidance of cross clamping, all of which are not well tolerated in high risk patients. Anatomically high-risk patients with anastomotic aneurysms from previous arch reconstruction may also benefit from these less invasive approaches. Medical devices designed specifically for the aortic arch are developing at a rapid pace and continue to evolve. Dedicated devices for zone 0-2 aortic arch repair are currently available under special access or being studied in clinical trials. Unfortunately, stroke continues to be the Achilles heel of endovascular approaches to the aortic arch, with cerebral embolism being the culprit in the majority of such cases. This perspective article describes the epidemiology, procedures, and mitigation strategies for current near-total and hybrid approaches to aortic arch pathology, and specifically addresses current means of embolic protection and future direction.

Chimney Technique in the Endovascular Repair of Juxtarenal Abdominal Aortic Aneurysm

Endovascular aneurysm repair is dependent on satisfactory proximal and distal sealing zones. Compromised proximal necks between the renal arteries and aneurysm may pose challenges to achieving a seal proximally. Techniques to extend this sealing zone proximally to healthier aorta include fenestrated and branched grafts which are not readily available particularly for emergent cases. The chimney technique involves preserving vital aortic branches with covered stents from the target vessels, running parallel to an aortic stent graft deliberately positioned above their ostia. This technique is described and illustrated with the aid of a case presentation.

Description of a phenomenon resembling spontaneous echocardiographic contrast in the venous system

Introduction. —According to Beppu et al., spontaneous echocardiographic contrast (SEC or smoke) is a pattern of “spontaneous swirling echoes originally visualized by transthoracic echocardiography in the enlarged left atrium of patients with mitral stenosis” (J Am Cardiol 1985;6:744–749). It has since been primarily associated with atrial fibrillation and flutter. The clinical significance of SEC is its association with left atrial thrombus, increased thromboembolic complications, and death. The pathogenesis of SEC seems to involve Rouleau formation between red cells and fibrinogen at low shear rates, which is an in vitro equivalent of blood stasis. Black noted that “Red cell aggregation, manifested as SEC, appears to be a precursor to thrombosis. Left atrial thrombi are rich in fibrin and red cells, resembling venous more than arterial thrombi” (Echocardiography 2000;17(4):373–382). Methods. —If left atrial thrombi are associated with SEC and resemble venous thrombi, it was hypothesized that actual venous thrombi in previously undescribed locations, most notably deep vein thrombosis, may equally be associated with SEC. We asked our coauthors (H.T. and M-C.Y.) to search for such a phenomenon among patients referred to the vascular laboratory for suspected venous thrombosis. Case Presentation. —In the following case series, we report an original phenomenon of swirling echogenicity in the venous system that we believe is SEC. The phenomenon was fairly rare (maximum 1.5% of referred patients, whereas deep venous thrombosis itself was 15-20%). The clinical significance of this phenomenon is discussed.

Endovascular Management of Thoracic Aneurysm

A 75-year-old male has been referred to your service after a contrast–enhanced spiral computed tomography (CT) performed for investigation of chronic cough revealed an incidental finding of a 7.3 cm thoracic aortic aneurysm (TAA). Past medical history includes moderate chronic obstructive pulmonary disease (COPD), hypertension, insulin-dependent diabetes and a history of coronary artery catheterization and stenting 5 years ago. The patient denies current angina symptoms. On examination, vital signs are stable, cardio-respiratory examination is within normal limits, and arterial examination reveals no carotid bruits, normal heart sounds without murmurs, no palpable abdominal masses and all upper and lower limb distal pulses are palpable. His routine blood work is within normal range.