ABSTRACT
Purpose: The use of endovascular coronary brachytherapy to prevent restenosis following percutaneous transluminal coronary angioplasty (PTCA) began in April 1997 at the Department of Interventional Cardiology of the Thoraxcenter at the University Hospital of Rotterdam. This article reviews the more than 250 patients that have been treated so far.Methods and Materials: The Beta-Cath System (Novoste), a manual, hydraulic afterloader with 12 90Sr seeds, was used in the Beta Energy Restenosis Trial (BERT-1.5, n=31), for compassionate use (n=25), in the Beta-Cath System trial (n=27) and in the Beta Radiation in Europe (BRIE, n=14). Since the Beta-Cath System has been commercialized in Europe, 57 patients have been treated and registered in RENO (Registry Novoste). In the Proliferation Reduction with Vascular Energy Trial (PREVENT), 37 patients were randomized using the Guidant-Nucletron remote control afterloader with a 32P source wire and a centering catheter. Radioactive 32P coated stents have been implanted in 102 patients. In the Isostent Restenosis Intervention Study 1 (IRIS 1), 26 patients received a stent with an activity of 0.75-1.5 µCi, and in the IRIS 2 (European 32P dose response trial), 40 patients were treated with an activity of 6-12 µCi. In two consecutive pilot trials, radioactive stents with non-radioactive ends (cold-end stents) and with ends containing higher levels of activity (hot-end stents) were implanted in 21 and 17 patients, respectively.Results: In the BERT-1.5 trial, the radiation dose, prescribed at 2 mm from the source train (non-centered), was 12 Gy (10 patients), 14 Gy (10 patients) and 16 Gy (11 patients). At 6-month follow-up, 8 out of 28 (29%) patients developed restenosis. The target lesion revascularization rate (TLR) was 7 out of 30 (23%) at 6 months and 8 out of 30 (27%) at 1 year. Two patients presented with late thrombosis in the first year. For compassionate use patients, a restenosis rate (RR) of 53% was observed. In the PREVENT trial, 34 of 37 patients underwent an angiographic 6-month follow-up. The doses prescribed at 0.5 mm depth into the vessel wall were 0 Gy (8), 28 Gy (9), 35 Gy (11) and 42 Gy (8). TLR was 14% in the irradiated patients and 25% in the placebo group. One patient developed late thrombosis. In the IRIS 1 trial, 23 patients showed an RR of 17% (in-stent). In the IRIS 2 trial, in-stent restenosis was not seen in 36 patients at 6-month follow-up. However, a high RR (44%) was observed at the stent edges.Conclusions: The integration of vascular brachytherapy in the catheterization laboratory is feasible and the different treatment techniques that are used are safe. Problems, such as edge restenosis and late thrombotic occlusion, have been identified as limiting factors of this technique. Solutions have been suggested and will be tested in future trials.
ABSTRACT
Intracoronary radiation therapy has been developed in an attempt to decrease restenosis after balloon angioplasty and stent implantation. Two parallel technologies, one employing radioactive stents, the other catheter-based radiation (using either beta- or gamma-emitters), have been the subject of both animal and human studies. In vivo intravascular ultrasound imaging studies have helped us to determine the morphologic effect of brachytherapy on the vessel wall. This article is aimed at revising the potential and limitations of this new technique and summarizing the results of the currently reported clinical trials.
ABSTRACT
The development of the heparin-coated (HC)-stent should be viewed against the backdrop of the early unfavorable results with noncoated stents in the pre-intravascular ultrasound and pre-ticlopidine era. Notwithstanding, results of pilot and randomized trials show a surprisingly low incidence of (sub)acute stent thrombosis under challenging circumstances, such as acute coronary syndromes. Considering the quite low incidence of early complications with noncoated second-generation stents, it may require large trials to prove the clinical efficacy of the heparin- coating against noncoated devices. However, even if the "added value" of the heparin-coating will never be clinically proven, it has helped to enhance the penetration of stent therapy in interventional cardiology. Unlike the situation in 1992, very few cardiologists will now disagree with the statement that stents contribute to the state-of-the-art treatment of patients with angina pectoris or acute myocardial infarction. A preliminary comparison of available trials also suggests that the heparin-coated Palmaz-Schatz stent (Cordis Corp., Waterloo, Belgium) is as effective as the noncoated stent plus abciximab treatment.
ABSTRACT
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.
ABSTRACT
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.
