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Biomedical subjects

H B Whitworth

Publications and source records attributed to H B Whitworth.

7 recordsLinked to original sources
PubMed1995

Effect of thromboxane A2 blockade on clinical outcome and restenosis after successful coronary angioplasty. Multi-Hospital Eastern Atlantic Restenosis Trial (M-HEART II)

BACKGROUND: Antithromboxane therapy with aspirin reduces acute procedural complications of coronary angioplasty (PTCA) but has not been shown to prevent restenosis. The effect of chronic aspirin therapy on long-term clinical events after PTCA is unknown, and the utility of more specific antithromboxane agents is uncertain. The goal of this study was to assess the effects of aspirin (a nonselective inhibitor of thromboxane A2 synthesis) and sulotroban (a selective blocker of the thromboxane A2 receptor) on late clinical events and restenosis after PTCA. METHODS AND RESULTS: Patients (n = 752) were randomly assigned to aspirin (325 mg daily), sulotroban (800 mg QID), or placebo, started within 6 hours before PTCA and continued for 6 months. The primary outcome was clinical failure at 6 months after successful PTCA, defined as (1) death, (2) myocardial infarction, or (3) restenosis associated with recurrent angina or need for repeat revascularization. Neither active treatment differed significantly from placebo in the rate of angiographic restenosis: 39% (73 of 188) in the aspirin-assigned group, 53% (100 of 189) in the sulotroban group, and 43% (85 of 196) in the placebo group. In contrast, aspirin therapy significantly improved clinical outcome in comparison to placebo (P = .046) and sulotroban (P = .006). Clinical failure occurred in 30% (49 of 162) of the aspirin group, 44% (73 of 166) of the sulotroban group, and 41% (71 of 175) of the placebo group. Myocardial infarction was significantly reduced by antithromboxane therapy: 1.2% in the aspirin group, 1.8% in the sulotroban group, and 5.7% in the placebo group (P = .030). CONCLUSIONS: Thromboxane A2 blockade protects against late ischemic events after angioplasty even though angiographic restenosis is not significantly reduced. While both aspirin and sulotroban prevent the occurrence of myocardial infarction, overall clinical outcome appears superior for aspirin compared with sulotroban. Therefore, aspirin should be continued for at least 6 months after coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1991

Multi-Hospital Eastern Atlantic Restenosis Trial. II: A placebo-controlled trial of thromboxane blockade in the prevention of restenosis following coronary angioplasty.

Since platelet interactions appear to play an important role in the development of restenosis, attenuation of thromboxane-mediated reactions may improve the long-term outcome following coronary angioplasty. Phase II of the Multi-Hospital Eastern Atlantic Restenosis Trial (M-HEART) is a prospective, randomized, placebo-controlled study of thromboxane blockade in the prevention of restenosis following successful coronary angioplasty. Two forms of thromboxane blockade are evaluated: aspirin (a nonspecific inhibitor of thromboxane synthesis) and sulotroban (a specific thromboxane receptor antagonist). The design of this multicenter trial and the rationale for use of sulotroban in the prevention of restenosis are reviewed in this report.

Angioplasty, Balloon, Coronary↗
PubMed1991

Clinical and angiographic determinants of primary coronary angioplasty success. M-HEART Investigators.

Clinical and anatomic determinants of the initial success of percutaneous transluminal coronary angioplasty were prospectively evaluated in 826 patients enrolled in the Multi-Hospital Eastern Atlantic Restenosis Trial (M-HEART). The 639 men and 187 women ranged in age from 31 to 85 years. Successful angioplasty (residual stenosis less than 50% and no major complications) was achieved in 886 (88.6%) of 1,000 lesions. Success rates were uniform among the eight individual centers. Outcome was not influenced by gender, age or other clinical features, including severity and duration of angina, prior myocardial infarction, rest pain, transient ST segment elevation, history of smoking or diabetes. In contrast, procedural outcome was significantly associated with lesion-specific angiographic factors. Stenoses 60% to 74%, 75% to 89%, 90% to 99% and 100% were associated with success rates of 96%, 90%, 84% and 69%, respectively (p less than 0.001). Angioplasty was less successful in calcified than in noncalcified lesions (82% versus 90%, p less than 0.01), in thrombotic than in nonthrombotic lesions (82% versus 90%, p less than 0.05) and in lesions in the right coronary artery than in other vessels (84% versus 90%, p less than 0.01). Outcome was not related to other anatomic variables, including lesion location (proximal versus distal), vessel size, eccentricity, stenosis length or translesional gradient. By multivariate logistic regression, preangioplasty percent stenosis, right coronary artery location and lesion calcification were demonstrated to be significant independent predictors of angioplasty success. Alternative clinical and angiographic variables did not contribute to this regression model.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1986

Effect of nifedipine on recurrent stenosis after percutaneous transluminal coronary angioplasty.

This double-blind, randomized study evaluated the effect of nifedipine on restenosis after coronary angioplasty. Two hundred forty-one patients with dilation of 271 coronary sites were randomized at the time of hospital discharge to receive nifedipine, 10 mg (123 patients), or placebo (118 patients) four times daily for 6 months. No patient was known to have coronary artery spasm. The mean duration of therapy was 4.4 +/- 2 (mean +/- SD) months for nifedipine and 4.3 +/- 2 months for placebo. A restudy angiogram was available in 100 patients (81%) in the nifedipine group and 98 patients (83%) in the placebo group. A recurrent coronary stenosis was noted in 28% of patients in the nifedipine group and in 29.5% of those in the placebo group (p = NS). The mean diameter stenosis was 36.4 +/- 23% for the nifedipine group and 36.7 +/- 23% for the placebo group (p = NS). By pill count, 78% of patients receiving nifedipine and 82% of those receiving placebo complied with the study drug regimen. Coronary stenosis recurred in 33% of patients in the placebo group and in 29% of patients in the nifedipine group who complied with the regimen and had angiograms (p = NS). In conclusion, the study did not demonstrate a significant beneficial effect of nifedipine on the incidence of recurrent stenosis after successful percutaneous transluminal coronary angioplasty.

Adult↗
PubMed1985

Influence of intimal dissection on restenosis after successful coronary angioplasty.

We studied 986 patients who underwent follow-up angiography after successful percutaneous transluminal coronary angioplasty (PTCA) to determine the influence of uncomplicated intimal dissection on restenosis rate. Angiographic evidence of intimal dissection after PTCA was present in 248 patients or 25%. After a mean follow-up time of 7 +/- 5 months (SD) the restenosis rate in patients without intimal dissection was 30% compared with 24% in patients with intimal dissection (p = .08). Patients with available transstenotic pressure gradients were divided according to the hemodynamic result into two subgroups: those with final gradients at the conclusion of PTCA of 15 mm Hg or less (n = 638) and those with gradients greater than 15 mm Hg (n = 244). Patients with intimal dissection had a significantly lower restenosis rate than patients without intimal dissection if the final gradient was 15 mm Hg or less (19% vs 28%; p less than .05). If the final gradient was greater than 15 mm Hg, the presence or absence of intimal dissection had no significant influence on restenosis rate, which was 35% and 39%, respectively (p = NS). We conclude that an uncomplicated intimal dissection after a successful coronary angioplasty has no adverse influence on angiographic restenosis. An excellent angiographic long-term outcome can be expected if the intimal dissection is associated with a favorable hemodynamic result.

Angioplasty, Balloon↗