nitinol and Aortic-Aneurysm

To evaluate whether MR angiography (MRA) is a useful tool for the follow-up of aortic aneurysms treated with nitinol endoluminal grafts.. We examined 28 patients treated with nitinol endovascular stents to repair an aortic aneurysm with CT angiography (CTA) and MRA. Eleven patients (group 1) underwent an MRA after a positive CTA for endoleak was observed. Afterwards, 17 patients (group 2) were scheduled for both follow-up examinations. The kind of endoleak that occurred and the maximum aortic diameter were compared. The sensitivity of CTA relative to MRA for detecting endoleaks in group 2 was calculated. Signal-to-noise ratios (SNRs) were measured in the aortoiliac lumen at the arterial phase in, above, and below the endoprostheses. Student's t-test was used to compare aneurysm dimensions and SNR measurements.. Three type III leaks were correctly assessed at both examinations; however, CTA was less sensitive (50%) than MRA in depicting type II or unclassified leaks. No differences in aneurismal size were observed between the two examinations or between arterial SNRs observed in or out of the devices.. MRA can provide all relevant information necessary for the follow-up of patients treated with nitinol endoprostheses, and performs better than CTA in detecting endoleaks.

Topics: Alloys; Aortic Aneurysm; Blood Vessel Prosthesis; Contrast Media; Creatinine; Follow-Up Studies; Humans; Image Processing, Computer-Assisted; Iohexol; Magnetic Resonance Angiography; Prosthesis Failure; Sensitivity and Specificity; Tomography, X-Ray Computed

Topics: Alloys; Aortic Aneurysm; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Endovascular Procedures; Humans; Hypersensitivity; Inflammation; Polyesters; Prosthesis Design; Risk Factors; Stents; Syndrome; Treatment Outcome

Provisional Extension To Induce Complete Attachment (PETTICOAT) technique has shown good results in the treatment of acute type B aortic dissections (ABAD). Usually, uncovered tubular stainless steel stents are used to promote distal true lumen reattachment.. We describe the Petticoat technique using a conic self-expanding nitinol device as distal uncovered stent in five cases of complicated ABAD. We used as distal uncovered stent the single-flared E-XL (Jotec-GmbH).. In one case, renal arteries were successfully stented through the large cells of the E-XL. No perioperative complications were reported. During follow-up (18-24 months), positive remodeling of the entire aorta occurred in 3 cases; in 1 case with associated thoracoabdominal aneurysm, false lumen thrombosis at the thoracic level with true lumen expansion at the visceral aorta was detected at the 18-month CT angiogram, and in 1 patient with Marfan syndrome, open surgical conversion with the E-XL explantation was performed after 24 months due to aneurysmal evolution at the visceral level.. The E-XL can be successfully used in ABAD. It adapts to different aortic diameters, and its major radial force promotes successful positive remodeling. The open cell structure allows visceral arteries stenting, and it can be removed without complications during open conversion.

Topics: Adult; Aged; Alloys; Aortic Aneurysm; Aortic Dissection; Aortography; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Computed Tomography Angiography; Endovascular Procedures; Female; Humans; Male; Middle Aged; Prosthesis Design; Self Expandable Metallic Stents; Time Factors; Treatment Outcome

Prolonged organ ischemia during complex aortic surgery is associated with increased morbidity and mortality. A novel hybrid graft (Gore Hybrid Vascular Graft) as composite of expanded polytetrafluorethylene vascular prosthesis that has a section reinforced with nitinol was investigated for feasibility and effectiveness during aortic repair.. Retrospective analysis of all consecutive patients treated with the hybrid vascular graft (HVG). Indication for graft implantation was surgeon's preference for branch revascularization in challenging aortic repair.. Within 26 months, 25 Gore HVGs and 17 conventional grafts were implanted in 12 patients (age, 73 years; range, 33-79 years, 8 men). Eleven patients were treated for thoracoabdominal aortic aneurysms and one for aortoiliac aneurysm (elective = 6, urgent = 6). Nine visceral debranching procedures, 2 Crawford procedures, and 1 repair of an internal iliac aneurysm were performed. The distribution of HVG use was left renal artery = 10, right renal artery = 9, superior mesenteric artery = 4, celiac trunk = 1, and internal iliac artery = 1. Time to restore visceral blood flow during visceral debranching was 7 ± 4 min for the Gore HVG vs. 12 ± 6 min for conventional grafts (P < 0.01).Technical success was achieved in all cases. At 12 months of median follow-up, cumulative patency of the HVGs was 96%.. The Gore HVG offers a new, simplified, and time-sparing technique for visceral anastomoses during complex aneurysm repair. However, long-term results are still lacking and need to be awaited.

Topics: Adult; Aged; Alloys; Aortic Aneurysm; Aortography; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Endovascular Procedures; Female; Humans; Male; Middle Aged; Polytetrafluoroethylene; Prosthesis Design; Retrospective Studies; Risk Factors; Time Factors; Tomography, X-Ray Computed; Treatment Outcome; Vascular Patency

To physiologically test the durability of a sutureless aortic stent-graft based on nitinol bonded to polyhedral oligomeric silsesquioxane (POSS) and poly(carbonate-urea) urethane (PCU) for 10 years according to Food and Drug Administration guidelines.. Aortic stent-grafts (n = 4) were tested in 37°C distilled water using simulated in vivo hydrodynamic pulse loading. After 400 million cycles, surface topography was assessed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Dynamic compliance was measured using a pulsatile flow phantom. Mechanical and elastic properties were determined by stress-strain studies and elastic deformation tests. Dynamic scanning calorimetry (DSC) and thermomechanical analysis (TMA) were used to assess thermal resistance. Comparison was made with a zero-cycled control.. All stent-grafts successfully completed accelerated pulsatile fatigue at 94±14-mmHg pulse pressure. SEM images confirmed uniform surface topography without any fractures. FTIR showed increased intensity of -NHCO- bonds, but there was no significant sign of biodegradation. Tensile stress of fatigue-tested polymer compared favorably with the zero-cycled control at 50% to 500% strain (p = 0.69). At a mean pressure range of 60 to 120 mmHg, overall compliance of the fatigue-tested grafts was 3.48±1.27%mmHg(-1)×10(-2) with no significant difference compared to control (3.26±0.65%mmHg(-1)×10(-2); p = 0.47). DSC and TMA showed comparable thermotropic transition.. Simulated physiological in vivo hydrodynamic loading has no significant degradative effect on an innovative sutureless stent-graft made from POSS-PCU nanocomposite polymer. Sutureless technology incorporating nitinol stents proved to be robust, with no separation over an accelerated 10-year cycle, which may allow development of durable stent-grafts with better compliance.

Topics: Alloys; Aortic Aneurysm; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Calorimetry; Compliance; Hydrodynamics; Materials Testing; Microscopy, Electron, Scanning; Nanocomposites; Organosilicon Compounds; Polymers; Polyurethanes; Prosthesis Failure; Pulsatile Flow; Spectroscopy, Fourier Transform Infrared; Stents; Stress, Mechanical; Surface Properties; Temperature; Tensile Strength; Time Factors

The association of aortic and common iliac artery aneurysms requires a special strategy to achieve distal seal during the endovascular exclusion of abdominal aortic aneurysms. Coil embolization of the internal iliac artery before the placement of a bifurcated endograft limb into the external iliac artery is a usual option. Such procedures are usually well tolerated but may result in buttock claudication, postprocedural sexual dysfunction, and colonic ischemia. We report on an alternative repair to preserve internal iliac artery patency using the Apollo iliac branched device.

Topics: Aged, 80 and over; Alloys; Aortic Aneurysm; Aortography; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Humans; Iliac Aneurysm; Male; Polytetrafluoroethylene; Prosthesis Design; Stents; Tomography, X-Ray Computed; Treatment Outcome

To evaluate our initial experience with hypogastric artery occlusion using a nitinol vascular plug during endovascular aortic aneurysm repair (EVAR).. We reviewed the records and images of 23 consecutive patients who underwent transluminal vessel occlusion of the hypogastric artery with a nitinol plug, as well as a cohort of 19 patients who underwent hypogastric artery embolization with coils in conjunction with EVAR.. There were no demographic differences between the two groups of patients. Hypogastric artery occlusion was successful in all cases when a nitinol vascular plug was used. When coils were used, there was one unsuccessful embolization which required a second procedure. The number of embolic devices used in the coil group was 7.53 (range, three to 13) compared with 1.35 (range, one to six) in the plug group (P < .05). Only one plug was used in 19 of 23 cases. The average cost to embolize per hypogastric artery was $1,496 compared with $470 when a nitinol plug was used. There were two instances of coil migration. No other intraoperative complications occurred. At one month follow up, seven patients (35%) in the coil group complained of buttock claudication compared with two patients (9%) in the nitinol plug group (P = .027).. Our experience demonstrates the safety and effectiveness of the nitinol vascular plug for hypogastric artery occlusion during EVAR. When compared with coils for hypogastric embolization during EVAR, nitinol vascular plugs are less expensive, produce less technical complications, and are associated with a significantly lower incidence of gluteal claudication.

Topics: Aged; Alloys; Aortic Aneurysm; Blood Vessel Prosthesis Implantation; Buttocks; Embolization, Therapeutic; Equipment Design; Female; Hospital Costs; Humans; Iliac Aneurysm; Intermittent Claudication; Ischemia; Male; Medical Records; Time Factors; Tomography, X-Ray Computed; Treatment Outcome

Two patients with dissecting (n = 1) and saccular (n = 1) aneurysms of the infrarenal abdominal aorta with very narrow proximal and distal aortic necks underwent treatment with percutaneous implantation of self-expandable polytetrafluoroethylene (PTFE)-covered nitinol stent-grafts on an off-label basis. The stent-grafts had maximum diameters of 13.5 mm and were deployed via 10-F introducer sheaths. Complete coverage of both aneurysms was achieved without evidence of endoleaks. The only complication observed was a pseudoaneurysm of the femoral access site in one patient, which was treated conservatively. Based on the experience described in this report, an aortic aneurysm with a narrow aortic neck can be safely treated with a PTFE-covered nitinol stent-graft.

Topics: Aged; Aged, 80 and over; Alloys; Aortic Aneurysm; Blood Vessel Prosthesis; Coated Materials, Biocompatible; Female; Humans; Male; Polytetrafluoroethylene; Stents; Treatment Outcome

To report the midterm results of the endovascular treatment of complicated type-B aortic dissection with use of stent-grafts.. Ten patients with acute (n = 4) or chronic (n = 6) complicated type-B dissection were treated with custom-made stent-grafts. Indications for treatment included uncontrollable hypertension with dissection extension (n = 3), renal ischemia (n = 1), and false lumen aneurysm (n = 6). Stainless-steel Z-stents covered with polyester grafts were placed in the initial six patients. Nitinol stents covered with ultrathin polytetrafluoroethylene were used in the remaining four patients. The patients were followed-up with helical computed tomography for a maximum of 30 months (mean, 20 mo).. There was one technical failure related to the access site. Early complications included deep venous thrombosis (n = 1) and embolic stroke (n = 1). Complete thrombosis of the thoracic false lumen was achieved in six patients and partial thrombosis was achieved in three. Aneurysms developed at the ends of the stainless-steel stents in two patients, requiring additional stent-graft placement. Despite successful remodeling of the thoracic aorta, three of four patients with distal reentry into the abdominal aorta experienced progressive abdominal aortic aneurysm (AAA). AAA rupture developed in two patients; one rupture was fatal and the other was treated with emergency surgery.. Endovascular treatment of complicated type-B aortic dissection is technically feasible and effective. Closely monitoring the treated aorta is essential to detect early aneurysm formation at the ends of rigid stents. Despite adequate sealing of the tears in the thoracic aorta, dissection with distal reentry phenomenon into the abdominal aorta may evolve into AAA with late rupture.

Topics: Alloys; Aortic Aneurysm; Aortic Dissection; Blood Vessel Prosthesis Implantation; Equipment Design; Female; Follow-Up Studies; Humans; Male; Middle Aged; Polytetrafluoroethylene; Stainless Steel; Stents; Time Factors; Tomography, X-Ray Computed

Our objective was to evaluate the accuracy of contrast-enhanced 3D MR angiography (MRA) in the follow-up of patients with endoluminally treated aortic aneurysms and correlate these findings with uni- or biphasic CT angiography (CTA). Forty MR angiograms in 32 patients with implanted aortic nitinol stent grafts were compared to CTA. Twenty-two MR examinations were correlated with arterial-phase CTA (uniphasic), and 18 MR examinations were correlated with biphasic CTA. Uniphasic CTA demonstrated three type-1/type-3 endoleaks and four reperfusion (type-2) endoleaks. In addition, MRA depicted two type-2 reperfusion endoleaks that were missed by CTA. Using biphasic CTA, two type-1/type-3 endoleaks and three reperfusion (type-2) endoleaks were detected; of those, delayed scanning detected three reperfusion (type-2) endoleaks missed during arterial-phase CTA. In addition to the findings by CTA, MRA depicted another type-2 reperfusion endoleak. Magnetic resonance angiography is at least as sensitive as uni- or biphasic CTA for detecting endoleaks and may consequently offer advantages in patients with contraindications to iodinated contrast agents.

Topics: Aged; Aged, 80 and over; Alloys; Aortic Aneurysm; Contrast Media; Female; Humans; Iliac Aneurysm; Magnetic Resonance Angiography; Male; Middle Aged; Observer Variation; Prosthesis Failure; Stents; Subtraction Technique; Tomography, X-Ray Computed

A new technique for percutaneous arterial grafting was developed using a unique metal alloy (nitinol) with a heat dependent memory. Ten tightly wound nitinol coils (5-15 mm in diameter and 2-5 cm in length) were straightened in ice water and passed via catheter into the iliac artery or abdominal aorta of nine animals. Long term patency (15 weeks) was demonstrated in all but one graft. In one animal, an experimentally created abdominal aortic aneurysm was successfully treated by interposition of a nitinol graft. This new technique may be a valuable adjunct to conventional treatment of both obstructive and aneurysmal arterial disease in man.

Topics: Alloys; Animals; Aorta, Abdominal; Aortic Aneurysm; Aortography; Blood Vessel Prosthesis; Catheterization; Dogs; Evaluation Studies as Topic; Punctures