Renal Function Salvage After Delayed Endovascular Revascularization of Acute Renal Artery Occlusion in Patients With Fenestrated-Branched Endovascular Aneurysm Repair or Visceral Debranching.

PURPOSE: To analyze the renal function and outcome after delayed (>6 hours) endovascular revascularization of acute renal artery occlusion (RAO) in patients with fenestrated-branched endovascular aneurysm repairs (EVARs) or open visceral debranching. METHODS: A single-center retrospective analysis was conducted involving 7 patients (mean age 61 years, range 49-72; 5 women) with 9 RAOs treated with endovascular revascularization between December 2014 and March 2017. Three patients had a solitary kidney with chronic renal insufficiency; 1 patient had bilateral occlusions as the acute event. Initial aortic surgery included 5 branched and 1 fenestrated EVAR as well as 1 open visceral debranching operation. Revascularization of the RAO was performed using aspiration thrombectomy, local lysis therapy, and stent-graft relining. The median time between initial aortic surgery and RAO was 10 months (range 0.5-17). RESULTS: Median renal ischemic time to revascularization was 24 hours (range 7-168). Technical success was 100%, with 1 procedure-related access complication. Temporary dialysis dependency occurred in 4 patients. Mean in-hospital stay was 17 days (range 7-32) with 1 postoperative death at day 10 due to cardiac arrest of unknown cause. Mean follow-up was 10.3 months (range 1.5-27) in 5 of 6 discharged patients. During follow-up, 1 reintervention for recurrent occlusion was performed. At follow-up imaging, all renal arteries were patent. No permanent dialysis dependency occurred. CONCLUSION: Renal function can be salvaged by delayed revascularization for RAO with prolonged renal ischemia. The endovascular approach with aspiration thrombectomy, local lysis, and stent-graft relining is a feasible technique for revascularization after RAO in patients with fenestrated-branched EVAR or open visceral debranching.

Acute Type A Aortic Dissection Treated Using a Tubular Stent-Graft in the Ascending Aorta and a Multibranched Stent-Graft in the Aortic Arch.

PURPOSE: To describe the combined use of a tubular stent-graft for the ascending aorta and an inner-branched arch stent-graft for patients with acute type A aortic dissection. TECHNIQUE: The technique to deploy these modular, custom-made stent-grafts is demonstrated in 2 patients with acute DeBakey type I aortic dissections and significant comorbidities precluding open surgery. Both emergent procedures were made possible by the availability of suitable devices manufactured for elective repair in other patients. After preliminary carotid-subclavian bypass, a long Lunderquist guidewire was introduced from the right femoral artery to the left ventricle for delivery of the Zenith Ascend and Zenith Branched Arch Endovascular Grafts under inflow occlusion. Bridging stent-grafts were delivered to the innominate and left common carotid arteries to connect to the 2 inner branches; the left subclavian artery was occluded. Both cases were technically successful and resulted in exclusion of the false lumen in the ascending aorta. The operating and fluoroscopy times did not exceed those of comparable elective procedures. The patients were rapidly extubated shortly after the procedure and without serious immediate complications. One patient survived 11 months with a satisfactory repair; the other succumbed to complications of recurrent pneumonia after 23 days. CONCLUSION: Endovascular treatment of patients with acute type A aortic dissection using a combination of tubular and branched stent-grafts in the ascending aorta is feasible and offers an alternative strategy to open surgery.

Carbon Dioxide Flushing Technique to Prevent Cerebral Arterial Air Embolism and Stroke During TEVAR.

PURPOSE: To describe the technique of carbon dioxide (CO2) flushing of thoracic stent-grafts to reduce the risk of cerebral air embolism. TECHNIQUE: To remove room air, thoracic stent-grafts were preoperatively flushed 2 minutes with carbon dioxide from a cylinder connected to the flushing chamber of the captor valves of Zenith custom-made endografts; this was followed by the standard saline flush. Thirty-six patients undergoing thoracic endovascular aortic repairs (TEVAR) involving the ascending aorta and the aortic arch received CO2-flushed Zenith endografts. One patient with a highly calcified arch experienced a minor stroke. CONCLUSION: Arterial air embolism is a potentially underappreciated problem of aortic endografting, especially in the proximal segments of the aorta. CO2 flushing may have the potential to reduce air embolization during TEVAR.

How to calculate the main aortic graft-diameter for a chimney-graft.

BACKGROUND: The aim of this paper was to present a mathematical model to calculate the required main aortic graft-diameter for parallel chimney-grafts. METHODS: Geometric approximation model, developed to allow for a standardized calculation of the main aortic graft-diameter determined by the aortic diameter and the diameter of the chimney-graft. RESULTS: We propose a mathematical formula using circular segments of the aorta and the chimney-graft and provide a table with recommended main aortic graft-diameters for single chimney-grafts of 6 and 8 mm. CONCLUSION: Geometric approximation can be used to calculate the required main aortic graft-diameter. For parallel running chimney-grafts a significant degree of oversizing is necessary to allow the main aortic body to surround the chimney and to prevent the occurrence of gutters, which may cause type-1 endoleaks.

Transcardiac endograft delivery for endovascular treatment of the ascending aorta: a feasibility study in pigs.

PURPOSE: To compare the technical feasibility and hemodynamic alterations during antegrade transcardiac access routes vs conventional transfemoral access (TFA) for endovascular treatment of the ascending aorta in a porcine model. METHODS: Antegrade transseptal access (TSA), transapical access (TAA), and TFA were used for implantation of custom-made endografts into the ascending aorta under fluoroscopy (6 pigs each). Hemodynamic parameters, myocardial and cerebral blood flow, and carotid artery blood flow were evaluated during baseline (T1), sheath advancement (T2), after sheath retraction (T3), and after endograft deployment (T4). RESULTS: Endograft deployment was feasible in all animals; all coronary arteries remained patent. Hemodynamic parameters were comparable in all 3 study groups during all measurements. During T2, transient hemodynamic alteration occurred in all groups, with transient severe valve insufficiency in TSA and TAA reflected by the higher pulmonary to mean arterial pressure ratio (p<0.05) as compared with TFA. Values stabilized again at T3 and remained stable until T4. The innominate artery was partially occluded in 4 (TSA), 3 (TAA), and 5 (TFA) animals. There was no deterioration of myocardial or cerebral perfusion during the procedures. Endograft deployment and fluoroscopy times during TAA were shorter than in TSA and TFA. CONCLUSIONS: TSA, TFA, and TAA to the ascending aorta are feasible for endograft delivery to the ascending aorta in a porcine model. Transient hemodynamic instability in TSA and TAA recovered to near preoperative values. TAA appeared technically easier.

Addressing persistent false lumen flow in chronic aortic dissection: the knickerbocker technique.

PURPOSE: To describe an innovative technique to occlude distal backflow into a false lumen aneurysm by controlled rupture of the dissection membrane after stent-graft implantation. TECHNIQUE: The "Knickerbocker technique" involves relining the true lumen in the descending aorta with an oversized thoracic tubular endograft, followed by controlled rupture of the dissection membrane using a large compliant balloon within the graft's midsection. This maneuver, which allows expansion of the stent-graft's midsection into the false lumen, was developed in order to occlude the large false lumen distally and thus prevent continued false lumen perfusion through distal abdominal entry tears. The technique has been successfully used in 3 patients with ruptured or symptomatic chronic false lumen aneurysm in type B aortic dissection. There was no short-term mortality associated with the procedure. After a mean follow-up of 8 months, the false lumen aneurysm remained thrombosed, with no mortality after a mean clinical follow-up of 22 months. CONCLUSION: The Knickerbocker technique appears to be feasible and effective in inducing false lumen thrombosis in selected patients who undergo stent-grafting for chronic type B aortic dissection.

Antegrade side branch access in branched aortic arch endografts: a porcine feasibility study.

PURPOSE: To describe the deployment technique for a single side branch arch endograft in a porcine model and prove the concept of transseptal or transapical antegrade access for catheterization and introduction of the mating stent-graft. METHODS: Six domestic pigs were operated with retrograde delivery of a single side branch arch endograft and antegrade introduction of a mating stent-graft using transseptal access (n=3) and transapical access (n=3). Technical feasibility, operating time, radiation parameters, and hemodynamic changes were studied. RESULTS: Transseptal and transapical access techniques were feasible in all animals. Catheterization and introduction of the mating stent-graft was feasible in 2 of 3 animals in the transseptal group and all animals in the transapical group. Technical feasibility was better in the transapical group, with shorter operating and fluoroscopy times and less hemodynamic impact during endograft deployment. Hemodynamic changes were short and reversible in all animals in both groups. CONCLUSION: Antegrade transcardiac access to the aortic arch for implantation of mating stent-grafts in branched arch endografting is feasible in a porcine model with reversible impact on hemodynamic measures during deployment. Transapical access was technically easier, with shorter operating and fluoroscopy times.