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Biomedical subjects

U Sigwart

Publications and source records attributed to U Sigwart.

At least 37 records · Page 2Linked to original sources
PubMed2000

Clinical and angiographic outcome after angiography-guided stent placement in small coronary vessels.

BACKGROUND: Although it is widely accepted that stenting confers favorable angiographic and clinical results in coronary arteries >/=3.0 mm in diameter, the outcome of stent placement in smaller vessels remains largely unclear. METHODS AND RESULTS: We sought to specifically determine the early and long-term clinical outcomes in a large series of 197 consecutive patients who underwent stent placement in 207 vessels <3.0 mm in diameter. Procedural success, accomplished in 97.3%, was accompanied by a significant reduction in lesion severity from 85% +/- 9% before to 3% +/- 7% diameter stenosis after the procedure (P =.0001) and a 0.5% incidence of subacute stent thrombosis. At 1 and 2 years of follow-up, survival rate without major target lesion-driven events was observed in 77.3% and 73.9% of patients, respectively. Repeat revascularization procedures accounted for most of these events; cardiac deaths (including those related to subacute stent thrombosis) and late (>30 days) myocardial infarctions were infrequent (2.4% and 1.0%, respectively). The 6-month angiographic binary instent restenosis rate was 30.1%. On multivariate analysis, diabetes mellitus (P =. 0275), small baseline reference vessel size (P =.0300), and stent size </=2.7 mm (P =.0111) were independently associated with an increased instent restenosis rate. CONCLUSIONS: Optimal angiography-guided coronary stenting of vessels <3.0 mm in diameter in association with the stringent use of a poststent combined aspirin-ticlopidine antiplatelet regimen confers a low risk of stent thrombosis, an acceptable incidence of angiographic instent restenosis, and a favorable long-term clinical outcome.

Aged↗
PubMed2000

Hybrid management of coronary artery disease and coarctation of aorta.

The treatment of coarctation of aorta with an additional cardiac lesion in adults remains a difficult surgical challenge. We present here an alternative, two-stage, hybrid approach that combined stent repair of aortic coarctation followed by coronary artery bypass operation in an adult with critical coronary lesions and a poor ventricle. This method may be a potentially useful strategy in reducing the comorbidity of operation to both lesions.

Aortic Coarctation↗
PubMed2000

Trials comparing coronary artery bypass grafting with percutaneous transluminal coronary angioplasty and primary stent implantation in patients with multivessel coronary artery disease.

With marked improvements in stent technology as adjunct to balloon angioplasty for multivessel coronary disease, several newer trials are currently in progress reviewing the optimal revascularization strategy. This review provides background from older studies and addresses the current progress and design of these newer trials.

Angioplasty, Balloon, Coronary↗
PubMed2000

Percutaneous interventional strategies in the treatment of chronic total coronary occlusions.

Chronic total coronary occlusions which make up 10% to 20% of all interventional procedures in high-volume centres remain a vexing problem for invasive cardiologists for 2 main reasons. First, they are only successfully recanalised in about 60% of attempts with most failures resulting from an inability to cross the lesions. Laser guidewire appears to be a promising innovation in overcoming this obstacle. Second, after initially successful recanalisation with conventional balloon angioplasty (PTCA), a high restenosis rate (range, 45% to 75%) is observed. Stent placement, by conferring maximal luminal expansion, appears to have resolved this problem to a large extent; both observational and randomised studies indicate that after stent placement, restenosis rate is at least halved that of PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1999

Non-elective intra-coronary stenting: are the clinical outcomes comparable to elective stenting at 6 months?

The aim of this study was to compare prospectively the clinical outcome of patients treated with intra-coronary stents as a non-elective/bailout procedure for acute or threatened vessel closure, with those undergoing elective stenting at 6 months. Sixty-four patients (60.2+/-11.7 y) who underwent non-elective stenting for abrupt or threatened vessel closure and/or sub-optimal results were prospectively compared with 68 patients (62+/-10.0 y) who were stented electively. All patients had broadly similar pre-procedural clinical profiles. However, patients in the elective group had a higher incidence of previous PTCA (10.2% vs. 0%, P = 0.01) and bypass surgery (30.9% vs. 6.3%, P = 0.0003) compared with the non-elective group. A total of 158 stents (1.19 per patient) were implanted in 132 patients with a procedural success rate of 99.3%. At 6 months follow-up there was no statistical difference in the primary composite end-point of death, myocardial infarction and the need of repeat revascularisation (10.9% vs. 5.8%, P = 0.35) between the two groups. However, patients in the non-elective group showed a higher incidence of unstable angina compared with the elective group (25% vs. 1.4%, P = 0.0004). The findings of this study suggest that stents (single or multiple) can be effectively implanted in non-elective situations with no increase in the incidence of death, non-fatal myocardial infarction, and the need of repeat revascularisation at 6 months compared with elective stenting.

Aged↗
PubMed1999

Short- and long-term histopathologic evaluation of stenting using a self-expanding nitinol stent in pig carotid and iliac arteries.

Stenting is increasingly being used to treat carotid artery disease. However, complications including distal embolization, stent thrombosis, stent collapse from external compression, the need for high-pressure inflation with increased neointimal response, or balloon rupture during stent expansion and stent loss are all potential problems and of concern. To address each of these specific concerns, a new stent was designed, which is self-expandable, made of nitinol, with temperature-dependent superelastic properties, and with high vessel wall surface coverage. Since this device has a number of novel characteristics, we aimed to assess the short- and long-term histopathologic response in pig carotid and iliac arteries. Single stents were deployed in pig carotid and iliac arteries after overstretch balloon injury. Angiograms were performed pre- and poststenting and prior to sacrifice. Intravascular ultrasound was used before implantation to determine vessel size. Vessels were examined histologically at 1 month (n = 6) and 6 months (n = 6) for morphometric analysis, hemorrhage and thrombus, endothelialization, and inflammatory and fibrotic responses. There was a 100% angiographic success rate at implantation. In one case, it was determined histologically that a single stent was implanted in a dissection plane of a pig's left iliac artery and was occluded by organized thrombus, with the true lumen being patent. At 6-month follow-up, this was the only evidence of a single stent occlusion, with flow adjacent to the stent in the true lumen. In the other vessels, the stents showed good vessel wall-stent apposition and the lumens were patent with a concentric and thin neointima. Inflammatory cells were rare and there were no mural thrombi. Coverage of the vessel wall by endothelial-like cells was complete at 1 month. The novel nitinol EndoStent appears to have favorable biocompatibility with minimal thrombus deposition or inflammatory response, and its use is feasible for clinical application in carotid and iliac arteries.

Alloys↗
PubMed1999

Electromechanical left ventricular behavior after nonsurgical septal reduction in patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVES: To investigate the electromechanical consequences of nonsurgical septal reduction in a group of patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Patients with HOCM may benefit symptomatically from nonsurgical septal reduction as an alternative to dual chamber pacing and sensing (DDD) pacing and surgical myectomy. METHODS: We studied 20 symptomatic patients with HOCM (12 men), mean age 52 +/- 17 years, before and after septal reduction using echocardiography and electrocardiogram (ECG). RESULTS: Septal reduction with a significant rise in cardiac enzymes was successfully achieved in all patients resulting in a 50% reduction in resting left ventricular (LV) outflow tract gradient within 24 h of procedure and an 80% reduction after six months. Left ventricular outflow tract diameter increased at 24 h with a further increase six months later. QRS duration increased by 35 ms at 24 h after procedure associated with right bundle branch block (RBBB) and significant rightward axis rotation in 16 patients. R-wave amplitude in V1 fell by 7 +/- 4 mm in 15/20 patients, 13 of whom developed reduction of septal long axis excursion. Left-axis deviation appeared in three patients and septal q-wave was suppressed in 12 long-axis excursion; peak shortening and lengthening rates all fell at the septal site by 20% at 24 h. Only septal excursion returned back to baseline values at six months. Wall motion also became incoordinate so that postejection septal shortening increased by three times control values at 24 h and by four times six months later. CONCLUSIONS: Nonsurgical septal reduction is associated with a drop in LV outflow tract obstruction and the creation of a localized myocardial infarction (MI) increasing LV outflow tract diameter. The technique also results in a consistent alteration of septal activation and secondary incoordination. The latter could play a significant role in gradient reduction and symptomatic improvement in a manner similar to that seen with DDD pacing.

Adult↗
PubMed1998

Clinical and Angiographic Results with the Multi-Linkª Coronary Stent System Ñ The West European Stent Trial (WEST).

BACKGROUND: The objectives for the West European Stent Trial (WEST) were to assess the safety and efficacy of the new ACS Multi-Linkª coronary stent system with regards to bleedings and vascular complications and incidence of major adverse cardiac events during 12 months follow-up. METHODS AND RESULTS: The balloon-expandable Multi-Link stent is made from a single hypotube and is composed of 316 L stainless steel. In an open, non-randomized, multicenter registry, 102 patients with angina pectoris to be treated with this stent were recruited from 7 European centers. Following stent implantation, patients were given heparin infusion and oral coumadin treatment was maintained for 3 months. Procedural success was achieved in 100 of the 102 patients (98%). One patient had subacute stent thrombosis and 6 patients had major bleeds during the hospital stay. All patients were alive at 12 months and 85% were free of angina pectoris. Nineteen patients (19%) reached a primary clinical endpoint; four patients underwent bypass surgery (two in connection with the stent procedure), four patients suffered an acute myocardial infarction and 11 had a repeat angioplasty of the target vessel. Quantitative angiography showed that the minimum lumen diameter had decreased from 2.66 +/- 0.34 mm after stent deployment to 2.02 +/- 0.58 mm at 6 months and the percent diameter stenosis had increased from 18 +/- 7% to 33 +/- 16%. The in-stent restenosis rate was 12% and appearance of a stenosis in the target vessel outside the stent occurred in an additional 5%. CONCLUSION: The WEST study has demonstrated a high degree of safety and efficacy of the Multi-Link stent with a low incidence of complications and clinical events during follow-up. The results compare favorably with data from other stents.

Journal Article↗