Williams, D.O.

Stent Thrombosis (Article)

2010-10-19T00:00:00Z

Intense investigation continues on the pathobiology of stent thrombosis (ST) because of its morbidity and mortality. Because little advance has been made in outcomes following ST, ongoing research is focused on further understanding predictive factors as well as ST frequency and timing in various patient subsets, depending upon whether a drug-eluting stent or bare-metal stent has been implanted. Although the preventive role of antiplatelet therapies remains unchallenged, new data on genomics and variability in response to antiplatelet therapy, as well as the effects of novel therapeutic agents and duration of therapy, have become available. The goal remains identification of patients at particularly increased risk of ST so that optimal prevention strategies can be developed and employed.

Effects of intracoronary beta-radiation therapy after coronary angioplasty: an intravascular ultrasound study. (Article)

1999-01-01T00:00:00Z

Efficacy of beta radiation in prevention of post-angioplasty restenosis (Article)

1998-01-01T00:00:00Z

Restenosis remains a major limitation of coronary angioplasty in spite of major advances in techniques and technology. Recent studies have demonstrated that ionizing radiation may limit the degree of this problem. Gamma radiation has been shown to be effective in reducing in stent restenosis in humans, and beta radiation following encouraging results in animals has been shown to be feasible in humans. The objective of this study was to assess the feasibility of a 5 F non-centered catheter to deliver beta radiation emitting seeds to the lesion site post angioplasty and its effect on restenosis. Following successful angioplasty, patients were randomized to treatment with 12, 14 or 16 Gy at the angioplasty site. This was delivered with a 5 F non-centered catheter. Twelve beta radiation emitting seeds (90Sr/Y) were delivered to an area 3 cm in length to cover the angioplasty site. Angiographic follow-up was performed at 6 months. Baseline and follow-up angiograms were performed by blinded investigators at a core laboratory. This interim report comprises the first 35 patients to complete 6-month angiographic follow-up. There were no major radiation incidents. Four patients had evidence of angiographic restenosis. The MLD (mm) and percent stenosis were 0.77 +/- 0.27/72.5 +/- 8.6 pre angioplasty, 2.08 +/- 0.4/25.7 +/- 9.8 post angioplasty and radiation and 2.05 +/- 0.59/25.7 +/- 19.8 at follow-up respectively. CONCLUSION: Beta radiation can be feasibly and safely delivered post coronary angioplasty with a very encouraging reduction of restenosis.

A comparison of directional atherectomy with coronary angioplasty in patients with coronary artery disease (Article)

1993-01-01T00:00:00Z

BACKGROUND. Directional coronary atherectomy is a new technique of coronary revascularization by which atherosclerotic plaque is excised and retrieved from target lesions. With respect to the rate of restenosis and clinical outcomes, it is not known how this procedure compares with balloon angioplasty, which relies on dilation of the plaque and vessel wall. We compared the rate of restenosis after angioplasty with that after atherectomy. METHODS. At 35 sites in the United States and Europe, 1012 patients were randomly assigned to either atherectomy (512 patients) or angioplasty (500 patients). The patients underwent coronary angiography at base line and again after six months; the paired angiograms were quantitatively assessed at one laboratory by investigators unaware of the treatment assignments. RESULTS. Stenosis was reduced to 50 percent or less more often with atherectomy than with angioplasty (89 percent vs. 80 percent; P < 0.001), and there was a greater immediate increase in vessel caliber (1.05 vs. 0.86 mm, P < 0.001). This was accompanied by a higher rate of early complications (11 percent vs. 5 percent, P < 0.001) and higher in-hospital costs ($11,904 vs $10,637; P = 0.006). At six months, the rate of restenosis was 50 percent for atherectomy and 57 percent for angioplasty (P = 0.06). However, the probability of death or myocardial infarction within six months was higher in the atherectomy group (8.6 percent vs. 4.6 percent, P = 0.007). CONCLUSIONS. Removing coronary artery plaque with atherectomy led to a larger luminal diameter and a small reduction in angiographic restenosis, the latter being confined largely to the proximal left anterior descending coronary artery. However, atherectomy led to a higher rate of early complications, increased cost, and no apparent clinical benefit after six months of follow-up.