nitinol and Coronary-Disease

A new martensitic nitinol stent with improved flexibility and radiopacity was tested to evaluate whether these differences improve initial or long-term outcome. Patients who underwent percutaneous revascularization of a discrete native coronary lesion were randomly assigned to the new stent (PARAGON, n = 349) or to the first-generation Palmaz-Schatz (PS) stent (n = 339). The primary end point was target vessel failure at 6 months (a composite of cardiac or noncardiac death, any infarction in the distribution of the treated vessel, or clinically indicated target vessel revascularization). Secondary end points were, among others, device and procedural success and angiographic restenosis. Mean age was 62 years; diabetes was present in 21% of patients, prior bypass surgery in 6%, and recent infarction in 22% (p = NS for comparison between the 2 randomized arms). The PARAGON stent group had smaller reference vessels (2.97 vs 3.05 mm, p = 0.05), more prior restenosis (8.0% vs 4.5%, p = 0.07), and a longer average stent length (21.3 vs 19.4 mm, p < 0.05). Device success was significantly higher in the PARAGON arm (99.1% vs 94.3%, p < 0.05). Death and infarction at 6-month follow-up were infrequent in both groups. There was no significant difference in death (2.0% vs 1.2%, p = 0.546), but a higher rate of infarction for the PARAGON cohort (9.2% vs 4.7%, p = 0.025). Although target vessel failure (20.3% vs 12.4%, p = 0.005) and target lesion revascularization (12.0% vs 5.9%, p = 0.005) were higher in the PARAGON group, there was no significant difference in 6-month follow-up in in-stent minimal lumen diameter or in the rate of binary angiographic restenosis. Both PARAGON and PS stents are safe and associated with infrequent adverse events. The PARAGON stent can be delivered more frequently than the first-generation PS stent. Although there was no significant difference in in-stent minimal lumen diameter or the frequency of angiographic restenosis, clinical restenosis was more frequent in the PARAGON group.

Topics: Adult; Aged; Aged, 80 and over; Alloys; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Disease; Elasticity; Equipment Design; Equipment Failure; Female; Follow-Up Studies; Humans; Male; Middle Aged; Myocardial Infarction; Recurrence; Stainless Steel; Stents; Time Factors; Treatment Outcome

Bare-metal stents are used to treat arterial stenotic lesions. Morbidity and mortality are less important compared with other techniques. Drug-eluting balloons are often used to treat stent stenosis. We reported the case of a bare-metal stent infection after drug-eluting balloon and a review on the subject.. Two weeks after percutaneous transluminal angioplasty with paclitaxel-eluting balloon and a bare-metal stent, our patient presented an infection of the stent. Diagnosis was based on the clinical presentation, positron emission tomography findings and isolation of Propionibacterium granulosum in repeated blood cultures. Adapted antibiotic therapy was given for three months with removal of the surgical bare-stent. Antibiotic therapy was interrupted after a second positron emission tomography. A literature search (PubMed and Cochrane) was performed on the subject.. We found 49 cases of peripheral bare-metal stent infection including our patient. This is a rare but serious complication with a high morbidity (25% amputation rate) and mortality (30%). It seems to be underestimated. Treatment is based on surgical ablation of the bare-metal stent and intravenous antibiotics. The role of the paclitaxel-eluting balloon is not clearly established but some authors believe that it can produce a local immunosuppression.. We report the first case of bare-metal stent infection after paclitaxel-eluting balloon. This complication is rare and difficult to diagnose. Manifestations are often limited to skin signs. Functional and vital prognosis is poor.

Topics: Aged, 80 and over; Alloys; Amoxicillin; Angioplasty, Balloon, Coronary; Anti-Bacterial Agents; Arteriosclerosis Obliterans; Bacteremia; Coronary Disease; Coronary Restenosis; Device Removal; Equipment Contamination; Female; Femoral Artery; Gentamicins; Gram-Positive Bacterial Infections; Humans; Immunosuppressive Agents; Paclitaxel; Penicillanic Acid; Piperacillin; Piperacillin, Tazobactam Drug Combination; Popliteal Artery; Propionibacterium; Prosthesis-Related Infections; Stents; Tomography, Emission-Computed, Single-Photon

This study sought to report the first-year clinical outcome with the nitinol self-expanding coil stent and to provide angiographic data on the effect of self-expansion during implantation and follow-up. Self-expanding stents do not reach their nominal diameter at implantation. The long-term effects may therefore depend, in part, on continued expansion after initial implantation.. Between January 1995 and January 1996, 86 stents were deployed in 64 patients for indication of suboptimal results. All patients were clinically followed up for 1 year, and 72% had follow-up angiography.. The majority (55%) of the lesions were class B2 or C. Balloon angioplasty increased the minimal lumen diameter from 1.07 +/- 0.73 mm to 2.24 +/- 0.57 mm; stent deployment further increased the diameter to 2.63 +/- 0.48 mm, and within-stent balloon dilatation to 2.96 +/- 0.62 mm. Angiographic follow-up performed at 7.8 +/- 1.1 months (range 7-9 months) showed that the minimal lumen diameter was 2.15 +/- 0.80 mm (late lumen loss of 0.81 +/- 0.69 mm), and the mean stent diameter expanded to 3.58 +/- 0.48 mm (self-expanding late stent gain of 0.62 +/- 0.55 mm). The extent of this expansion was inversely related to the late lumen loss (r = 0.67, slope 0.81, P <.01). At 1 year 51 (80%) of 64 patients were event free; 3 had undergone coronary artery bypass grafting, 2 had had a myocardial infarction, and 9 had repeat angioplasty. In the subgroup of a simple lesion (<15 mm) covered by 1 stent, 18 (86%) of 21 patients were event free.. The self-expanding nitinol stent exerts its acute effect on minimal lumen diameter through its intrinsic radial force aided by balloon expansion. The stent continues to expand until it reaches its nominal diameter over the follow-up period. The extent of this expansion is inversely related to the late lumen loss, leading to an acceptable rate of long-term clinical events in this first cohort of patients with complex disease morphology.

Topics: Alloys; Coronary Angiography; Coronary Disease; Female; Follow-Up Studies; Humans; Male; Prosthesis Design; Stents

Percutaneous transluminal coronary angioplasty (PTCA) is currently one of the most common treatments for obstructive coronary artery disease. The long term success of the treatment, however, is severely limited by restenosis. Recently, different investigators have begun to study the possibility of radiation therapy in restenosis prevention and have shown promising results. However, an optimal radiation delivery device for delivering a highly localized radiation dose to the arterial medial layer while preserving the viability of the artery has yet to be established. In this article, we discuss the development of a unique mixed gamma/beta brachytherapy source capable of delivering high radiation dose to a 0.5 mm thick vessel wall by proton-beam activating an existing nickel titanium stent to produce vanadium-48. The dose distribution of the activated stent is determined by computer simulation using MCNP Monte Carlo code and is verified by radiochromic film measurement.

Topics: Alloys; Angioplasty, Balloon, Coronary; Brachytherapy; Coronary Disease; Coronary Vessels; Electrons; Equipment Design; Humans; Phantoms, Imaging; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Recurrence; Stents

Chronic total occlusion remains a relative contraindication and the main cause of failure of coronary angioplasty. Previously available hydrophilic guidewires had numerous limitations. The Crosswire is a new 0.014" hydrophilic nitinol guidewire which can be accommodated by very-low-profile balloon catheters and has a shapeable and highly radiopaque platinum-iridium coiled tip. This guidewire was used in 55 patients with 56 chronic coronary occlusions in which recanalization by conventional guidewires had failed. Clinical success was 79%. Coronary perforation occurred in two cases, one of them requiring pericardiocentesis for tamponade. These results illustrate the usefulness of this new guidewire in the treatment of chronic total occlusions.

Topics: Adult; Aged; Aged, 80 and over; Alloys; Angioplasty, Balloon, Coronary; Coronary Disease; Equipment Design; Female; Humans; Male; Middle Aged; Radiography; Recurrence; Retreatment; Surface Properties; Treatment Failure

Topics: Adult; Aged; Aged, 80 and over; Alloys; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Disease; Equipment Design; Female; Humans; Male; Middle Aged; Recurrence; Retreatment; Surface Properties; Treatment Failure

There is a paucity of experimental data regarding self-expanding stents. This study evaluated the acute and chronic effects of CardioCoil, a self-expanding nitinol coil stent, in porcine coronary arteries.. Twenty-three self-expanding nitinol stents were implanted without associated balloon angioplasty in normal coronary arteries of 12 pigs, which were serially sacrificed up to 6 months. Angiographic and histologic analyses were performed to evaluate the deployment characteristics, patency rates, neointimal response, and unique features of the self-expanding nature of the CardioCoil stent.. All stents were successfully deployed and remained patent acutely. Three undersized stents migrated proximally and there was one episode of subacute thrombosis in an oversized stent. The remaining stents were patent throughout the survival period and neointimal responses were favorable for up to 6 months (all mean neointima < 200 microns up to 6 months). There was evidence of continuing stent expansion over time (stent diameter 2.85 +/- 0.78 mm immediately after deployment and 3.24 +/- 0.97 mm at follow-up) and the majority of stent struts were in the adventitia by 6 months. Re-endothelization occurred starting one week after implantation and was complete by 8 weeks.. This study shows that the CardioCoil self-expanding nitinol coil stent, is associated with favorable deployment characteristics and patency rates, although appropriate sizing is more crucial than with balloon-expandable stents. More importantly, there appears to be a "dissociation' between the deep vessel wall injury by the chronic strut expansion process and the neointimal reaction, unlike balloon-expandable stents.

Topics: Alloys; Animals; Coronary Disease; Equipment Design; Female; Male; Stents; Swine; Time Factors; Tunica Intima; Vascular Patency

Percutaneous treatment of bifurcation lesions has been consistently shown to be associated with lower acute success rates, higher initial complication rates, and an increased rate of restenosis when compared with findings in nonbifurcation lesions. Recent analysis of data from a CAVEAT subgroup suggests that directional atherectomy of bifurcation lesions can improve initial success rates and lower restenosis rates but at the cost of high complication rates. Reports from several angioplasty series document improved success rates and lower complication rates with the use of a two-wire technique to protect side branches when treating bifurcation lesions. Our experience with a two-wire atherectomy technique that uses a nitinol wire to protect important side branches is presented.

Topics: Adult; Aged; Aged, 80 and over; Alloys; Atherectomy, Coronary; Coronary Angiography; Coronary Disease; Electrocardiography; Equipment Design; Female; Humans; Male; Middle Aged; Treatment Outcome