Background —Dual therapy with ticlopidine and aspirin has been shown to be as effective as or more effective than conventional anticoagulation in patients with an optimal result after implantation of intracoronary metallic stents. However, the safety and efficacy of antiplatelet therapy alone in an unselected population has not been evaluated. Methods —Patients were randomized to conventional anticoagulation or to treatment with antiplatelet therapy alone. Indications for stenting were classified as elective (decided before the procedure) or unplanned (to salvage failed angioplasty or to optimize the results of balloon angioplasty). After stenting, patients received aspirin and either ticlopidine or conventional anticoagulation (heparin or oral anticoagulant). The primary end point was the occurrence of bleeding or peripheral vascular complications; secondary end points were cardiac events (death, infarction, or stent occlusion) and duration of hospitalization. Results —In 13 centers, 236 patients were randomized to anticoagulation and 249 to antiplatelet therapy. Stenting was elective in 58% of patients and unplanned in 42%. Stent implantation was successfully achieved in 99% of patients. A primary end point occurred in 33 patients (13.5%) in the antiplatelet group and 48 patients (21%) in the anticoagulation group (odds ratio=0.6 [95% CI 0.36 to 0.98], P =0.03). Major cardiac-related events in electively stented patients were less common (odds ratio=0.23 [95% CI 0.05 to 0.91], P =0.01) in the antiplatelet group (3 of 123, 2.4%) than the anticoagulation group (11 of 111, 9.9%). Hospital stay was significantly shorter in the antiplatelet group (4.3±3.6 versus 6.4±3.7 days, P =0.0001). Conclusions —Antiplatelet therapy after coronary stenting significantly reduced rates of bleeding and subacute stent occlusion compared with conventional anticoagulation.

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Previous studies have investigated the radiation dose to doctors and patients during coronary angiography and angioplasty, but most of them were retrospective, conducted in the prestent era, and results have not been consistent. Effective dose of 57 patients undergoing coronary angiography and/or angioplasty was assessed by using a dose-area product (DAP) to effective dose conversion factor. Radiation exposure risks to patients were then calculated for each procedure. Thermoluminescent dosimeters, mounted on a specially designed catheter that was advanced to the left or right sinus of Valsalva, were used to measure the dose received by the coronary arteries. Mean effective dose received by patients were 5.0 +/- 0.5 mSv for coronary angiography, 6.6 +/- 1.0 mSv for angioplasty, 10.2 +/- 1.5 mSv for angioplasty followed by stent implantation, 13.6 +/- 2.5 mSv for angiography followed by ad hoc angioplasty, and 16.7 +/- 2.8 mSv for angiography followed by ad hoc angioplasty and stent implantation. Patient risk of developing cancer after each procedure was 0.025%, 0.033%, 0.051%, 0.068%, and 0.084%, respectively. Corresponding mean coronary irradiation doses were 24 +/- 2.5, 31.0 +/- 3.6, 43.6 +/- 7.2, 55.0 +/- 7.5, and 64.7 +/- 5.6 mGy, respectively. A linear relationship of the DAP and the dose at the coronary arteries was found: DAP = 1,273 (cm(2)) x coronary dose (mGy). Radiation exposure to coronary arteries and associated risk to patients are relatively low, even following complicated, multivessel angioplasty with stent implantation. Our method can be used for calculation of radiation risk to patients and radiation dose to coronary arteries by using external dosimeters. Cathet. Cardiovasc. Intervent. 51:259-264, 2000.

The length of the left main coronary artery has been measured in IOO coronary cineangiograms and in IOO postmortem hearts. The results indicate that an early bifurcation of the left main coronary artery is very much more common than previously suspected. The risks of aortic valve operation in cases with an early bifurcation are discussed.One of the advances in aortic valve surgery has been perfusion of the coronary arteries by direct cannulation during valve replacement. It has been suggested (Furlong et al., 1972) that a short left main coronary artery or a wide angle between its two main branches may result in underperfusion of the left circumflex artery or less commonly the left anterior descending artery. In such cases with an early bifurcation of the left main coronary artery the coronary cannula may selectively perfuse one main branch and to a greater or lesser degree occlude the other. Thus, a portion of myocardium remains underperfused throughout the bypass and infarction may result. The incidence of short left main coronary artery was therefore determined (a) in ioo coronary cineangiograms and (b) in ioo postmortem specimens with normal hearts. MethodsThe ioo coronary cineangiograms were carried out in the cardiac department at St. Thomas' Hospital, using Judkins or Sones techniques. The orifice of the main coronary artery could usually be visualized by spill-back of contrast medium during selective injection. The distance between this point and the bifurcation of the left main coronary artery was measured in a single frame of the left selective coronary cineangiogram in the right anterior oblique position. Errors of magnification were corrected by photographing a perforated metal ruler (i cm perforations) at midchest level and adjusting the coronary artery measurement to this standard. In 6 cases, measurement of the left main coronary artery was technically impossible either because the vessel overlay some radio-opaque structure in this projection, or else because of very severe aortic regurgitation which caused the spill-back to be rapidly diluted with nonopaque blood. In one case the circumflex artery arose from the right coronary artery. Thus a total of I07 consecutive cases was examined.The postmortem hearts of normal size were obtained from Ioo consecutive necropsies performed at St. George's Hospital (by M.J.D.) on cases of accidental death. The hearts were removed from the chest and fixed in formal saline. The length of the left main coronary artery (x) was measured as shown in Fig. i.The volume of the fixed ventricle was then assessed by filling the cavity with glass beads and measuring the displacement of the beads. No volume exceeded 200 ml. The left ventricular wall including the interventricular septum was then dissected from the rest of the heart and weighed. All fell within the normal range (120-200 g). ResultsThe lengths of the left main coronary arteries measured in the coronary cineangiographs are shown in FIG. i Diagram illustrating the measurements of the left main coronary artery a...