Christina Lohrenz

Distal False Lumen Occlusion in Aortic Dissection With a Homemade Extra-Large Vascular Plug: The Candy-Plug Technique

Purpose To report a technique to create an extra-large vascular plug for occlusion of a large distal false lumen in chronic aortic dissection. Technique The “candy-plug” technique is demonstrated in a 58-year-old multimorbid man with a history of complicated acute type B aortic dissection and a 9-cm chronic thoracic false lumen aneurysm. The patient underwent a staged repair with a cervical debranching procedure as a first step and a thoracic endovascular aortic repair from the innominate artery to the celiac artery as a second step. To occlude the large false lumen from a distal route, a stent-graft was modified on-table with a diameter-restricting suture, giving it a wrapped candy–like shape. This plug was deployed into the false lumen, and the remaining opening was occluded with a standard vascular plug. On 3-month follow-up imaging, the thoracic false lumen aneurysm remained completely thrombosed. Conclusion The candy-plug technique can facilitate complete occlusion of chronic thoracic false lumen aneurysm by prohibiting distal false lumen backflow.

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 grafts midsection. This maneuver, which allows expansion of the stent-grafts 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.

Hemodynamic impact of transseptal access to the ascending aorta in a porcine model.

Purpose To evaluate the hemodynamic impact of transseptal sheath access to the ascending aorta using increasing sheath diameters. Methods Transseptal puncture was performed in 6 pigs (62 ± 9 kg) facilitating guidewire passage across the left heart to the descending aorta to establish transseptal through-and-through access into the ascending aorta. Hemodynamic parameters were evaluated during 6- to 16-F sheath deployments and after sheath retraction according to a standardized protocol. Fluorescent microspheres were injected for quantitative assessment of myocardial and cerebral perfusion and left-right shunting volume. Results Cardiac output, heart rate, and central venous pressure (CVP) were stable throughout the study in all animals. The ratio between pulmonary artery pressure and mean arterial pressure was significantly higher during sheath deployment compared to after retraction (p<0.01), indicating transient mitral valve insufficiency. The ratio between left atrial pressure and CVP was significantly higher with the sheath in place (p<0.01), signaling transient left-right shunting; the hemodynamic alteration disappeared after sheath retraction. Myocardial perfusion (p=0.224), cerebral perfusion (p=0.209), and left-right shunting volume (p=0.111) were not significantly affected by the transseptal access. Conclusion Transseptal access to the ascending aorta in a porcine model is feasible without persisting hemodynamic impairment or severe influence on myocardial or cerebral perfusion even with up to 16-F sheaths. Potential adverse effects need to be addressed before clinical use of this alternative access to the ascending aorta, aortic arch, and its side branches.

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.

Proximal thoracic endograft displacement rescued by balloon-assisted pull-back, external shunting, and in situ fenestration of the left carotid artery

Proximal displacement of thoracic aortic endografts is a catastrophic adverse event, which rarely occurs but is associated with extremely high morbidity and mortality. We describe herein the case of a patient with accidental proximal displacement of a thoracic endograft with occlusion of all supra-aortic branches, successfully rescued by the combination of three advanced endovascular techniques: (1) aggressive pull-back maneuver with a compliant balloon; (2) establishment of an arterio-arterial temporary shunt to the occluded carotid artery over sheaths; and (3) in-situ fenestration of the occluded carotid artery.

Surgical reconstructions in peripheral arterial occlusive disease

The prognosis of patients suffering from peripheral arterial occlusive disease (PAD) is directly correlated with the severity of the disease. In critically ischemic legs, after one year only 50% will be alive with a preserved leg. The other 50% will die or undergo an amputation during this time. Reconstructive surgery is highly effective in PAD caused by extensive arterial lesions. Depending on the localization of the occlusion, operative procedures range from local desobliteration to profundoplasty and from aortofemoral to femorodistal bypass procedures. Especially in critical ischemia, time is of the essence for limb salvage. Evidence-based data for diagnosis and operative treatment are described in detail. Only the consequent use of these critical techniques can improve the prognosis of these patients.

Back-table modification of a bifurcated infrarenal stent-graft to aortomonoiliac for emergencies.

Purpose To describe a simple and quick technique for converting a Zenith bifurcated stent-graft to an aortouni-iliac device for emergency treatment of hemorrhage when a suitable marketed stent-graft is not readily available. Technique The technique is described in an emergent case involving a 72-year-old man presenting with an aortoduodenal fistula and acute gastrointestinal bleeding. The Zenith device was prepared and flushed in the typical fashion. An extra stiff Lunderquist wire was advanced through the graft for better stability during the modification. The peel-away sheath was advanced beyond the hemostatic valve to allow partial release of the graft from the back then the grey positioner was retracted while the sheath was held firmly on the table, partially deploying the iliac limbs from the back side of the sheath. An occluding non-absorbable braided suture was placed at the short limb of the bifurcated graft close to the middle of the contralateral limb stent, through the webbing connecting both limbs below the flow divider of the bifurcated Zenith device. The graft was then resheathed using manual pinching of the graft or compression with umbilical tape. In the illustrated case, the stent-graft was intentionally deployed with the uncovered stents below the renal arteries to facilitate easier explantation later on. Conclusion Back-table modification of stent-grafts is feasible in emergencies for operators familiar with all technical aspects and potential risks of the modifications.

TCT-135 Antegrade Transapical Branched Aortic Arch Endograft - a Feasibility Study in Pigs

hemodynamic conditions. A saccular aneurysm without collateral branch will thrombose quickly. If a collateral branch is present the flow is directed towards this branch leading to shrinkage of the aneurysm. Animal experiments show excellent results. Moreover, as demonstrated in animal and human studies this MFM* preserves the collateral branches allowing the possibility to cover any artery without compromising the flow (renal, digestive arteries, supra aortic vessels.) Results: 40 peripheral An. (iliac:23, femoral:1, popliteal:5, renal:8, mesenteric:1, carotid: 1, Subclavian : 1) were treated with the MFM* (male:31, mean age 62+/-8 y) (52 stents Ø 5 to 14 mm; length 40 to 120 mm) were implanted to treat these aneurysms, by femoral approach (39 cases), brachial approach (1 case), Technical success in all patients. No complications. All An. thrombosed with diameter reduction in some pts. The thrombosis could take several weeks depending on the importance of collateral branches. 6 month to 36 month follow up will be presented and we will discuss the time needed to achieve exclusion of the An. All the side branches remained patent. Conclusions: A new concept of stent, the MFM* (without any covering) is developed to treat An. It opens a new approach to treat peripheral An. avoiding most of the complications encountered with current endovascular techniques. The results obtained seem promising. A larger study is ongoing.