Katsuya Ueno

Transluminal endovascular branched graft placement for a pseudoaneurysm: Reconstruction of the descending thoracic aorta including the celiac axis

We I have previously reported a successful transluminal endovascular placement of a branched graft that had a sidearm extending into the left subclavian artery for repair of type B aortic dissection. The sidearm was properly positioned by catching and pulling back the free end of a detachable wire attached to its end by means of a gooseneck snare wire, which was percutaneously inserted through the left brachial artery. However, it is impossible to place sidearm grafts into the celiac axis and renal arteries in a similar manner. In this article, we describe a new method of inserting a sidearm into the celiac axis and report successful transluminal endovascular repair of a pseudoaneurysm with the use of the branched graft. A 73-year-old man with severe chronic renal failure requiring hemodialysis had previously undergone surgical repair of an aneurysm of the descending thoracic aorta. However, a pseudoaneurysm of the descending thoracic aorta resulting from dehiscence of the suture line at the proximal and distal anastomoses after composite graft surgery had continued to dilate, reaching 80 mm in diameter. Although surgical treatment was attempted, the effort was given up because of marked adhesions caused by a previous thoracotomy. He was admitted to our hospital for endovascular treatment of the pseudoaneurysm. The structure of the Inoue endovascular graft was previously described in detail. 2 The graft was constructed from a Dacron polyester fabric cylinder and the surface was supported by multiple rings of extra-flexible nickel titanium wire. The patient gave informed consent in conformance with the protocols approved by the institutional review board of Takeda Hospital. Endovascular grafting with the straight graft was performed on June 28, 1995. Although the proximal communication was completely obliterated after the procedure, the distal communication persisted because the distal orifice of the pseudoaneurysm was in close proximity to the celiac axis. Although transluminal embolization was

Multislice Computed Tomography Accurately Quantifies Left Atrial Size and Function After the MAZE Procedure

Background— Although the MAZE procedure allows for the recovery of sinus rhythm and left atrial (LA) mechanical function in the great majority of patients with chronic atrial fibrillation (AF), the effects of MAZE on the precise LA geometry and wall motion remain to be elucidated. We hypothesized that LA size and mechanical function in patients with chronic AF and mitral valvular disease are well restored after MAZE. Methods and Results— We studied 14 patients (MAZE group: mean±SD age, 63.9±8.6 years; 8 men and 6 women) who underwent MAZE for chronic AF and mitral valve surgery and 10 patients with sinus rhythm (coronary artery bypass graft [CABG] group: age, 70.0±7.9 years; 5 men and 5 women) who underwent CABG at Takeda Hospital between February 2002 and September 2005. MAZE was conducted by the endocardial application of radiofrequency ablation with a temperature-controlled multipolar radiofrequency catheter. LA volume and booster function were quantitatively evaluated by multislice computed tomography at 17.9±10.0 months (MAZE group) and 15.3±13.6 months (CABG group) postoperatively. All patients with MAZE were free of AF and other atrial arrhythmias during the follow-up period. In the CABG group, LA maximal and minimal volumes and ejection fraction were 109±12 mL, 82±11 mL, and 26±10%, respectively. In the MAZE group, LA maximal volume was 139±17 mL (P=0.187 versus CABG), and LA minimal volume was 121±16 mL (P=0.082 versus CABG), with an ejection fraction of 15±7% (P=0.004 versus CABG). In both groups, all parts of the LA wall contracted toward the geometric center of the LA. The extent of wall motion was significantly worse in the MAZE group compared with the CABG group. In both groups, LA booster function was inversely correlated with LA maximal volume. Conclusions— MAZE with radiofrequency ablation is safe and effective for the restoration of sinus rhythm in patients with chronic AF and mitral valve disease. However, chronic AF associated with mitral valve disease deteriorates LA mechanical function diffusely throughout the LA wall. Further studies with the use of multislice computed tomography are needed to sequentially evaluate LA function after MAZE in patients with and without mitral valve surgery.

Transluminal repair of an infrarenal aortoiliac aneurysm by a combination of bifurcated and branched stent grafts

Transfemoral endovascular repair with a combination of bifurcated and branched stent grafts enables aortoiliac reconstruction with internal iliac perfusion preserved. We report a case of successful endovascular repair of aortoiliac aneurysm with use of a bifurcated and branched stent‐graft. Cathet. Cardiovasc. Intervent. 47:491–494, 1999.

Registration of Preoperative CTA and Intraoperative Fluoroscopic images for Assisting Aortic Stent Grafting

We investigated a registration method between preoperative 3D-CTA and intraoperative fluoroscopic images during intervention. Our final goal is assisting endovascular stent grafting for aortic aneurysm. In our method, DRR (Digitally Reconstructed Radiograph) are generated by voxel projection of 3D-CTA after extracting an aorta region. By increasing/decreasing CT value in the aorta region of CTA, DRR with/without contrast media injection are obtained. Subsequently we calculate matching measures between DRR and fluoroscopic images iteratively by changing imaging parameters. The most similar DRR to fluoroscopic image is selected. We investigated characteristics of several matching measures using simulated fluoroscopic images. From simulation results, we use M-estimator of residual in our method. From an application example to clinical data, registration was successfully applied by M-estimator of residual.

A System for Computer-Assisted Design of Stent-Grafts for Aortic Aneurysms Using 3-D Morphological Models

A three-dimensional model was constructed from helical CT images for abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA). A stent-graft was designed and positioned endoluminally on the computer. One hundred and nine stent-grafts for 101 patients were designed by this method and deployed well in all patients. The design time was reduced from 4 to 0.5 hr.

Successful Repair of Thoracoabdominal Aortic Aneurysm Secondary to Chronic Dissection by Hybrid Therapy Comprising Surgical Visceral Reconstruction and Dual Inoue Stent Graft Implantation

Crawford type II thoracoabdominal aortic aneurysm (TAAA) secondary to chronic dissection was successfully treated with hybrid therapy comprising surgical visceral reconstruction and dual Inoue stent graft implantation. The proximal single-branched Inoue stent graft effectively sealed the entry located near the left subclavian artery and simultaneously excluded the TAAA, while the distal tubular Inoue stent graft sealed the reentry; thus, the artery of Adamkiewicz was left unexcluded and intact between the two Inoue stent grafts. The visceral arteries were reconstructed using a quadrifurcated retrograde bypass with posterior aortic tunneling and end-to-end distal anastomosis to all four vessels to achieve a curved and smooth configuration.

Registration of preoperative CTA and intraoperative fluoroscopic image sequence for assisting endovascular stent grafting

We have investigated a registration method between pre-operative 3D CT angiography (3D-CTA) and intra-operative fluoroscopic image sequence (with/without contrast injection) during intervention. Most registration methods are developed for assisting neurosurgery or orthopedic surgery, but our method is developed for interventional procedure such as endovascular stent grafting. In our method, DRR (Digitally Reconstructed Radiograph) are generated by voxel projection of 3D-CTA after extracting an aorta region. By increasing/decreasing CT value in the aorta region of CTA, DRR with/without contrast media injection are obtained. Subsequently we calculate distance (or similarity) measures between DRR and fluoroscopic image iteratively by changing imaging parameters. The most similar DRR to fluoroscopy is selected. We validated our algorithm by using simulated/clinical fluoroscopic images and DRR (with/without contrast media injection) of thorax and abdomen. Several distance (or similarity) measures were investigated in this experiment. Validation results show that M-estimator of residual is good as matching measure, and registration is well performed for almost all cases. However, accuracy is not enough for non-contrasted thoracic images, and calculation time should be reduced for all cases.