Multicenter evaluation of a new fixed-wire coronary angioplasty catheter system: clinical and angiographic characteristics and results.

Coronary angioplasty is increasingly used as an attempt to revascularize patients with severe coronary artery disease. To determine the efficacy of such treatment, a new fixed wire angioplasty catheter was evaluated by a multicenter group in a non-randomized fashion in 50 patients, average 58 +/- 11 years (+/- 1 SD), 58% men. Forty-four percent had a prior revascularization procedure (28% angioplasty, 16% coronary bypass surgery), 38% had a prior Q-wave myocardial infarction, 43% had grade 4 angina, and 60% multiple vessel disease. Angioplasty was attempted in 63 lesions which were located in a mid to distal location in 69%, with a proximal tortuosity score of 1.8 (2 = 45-60 degrees entrance angle), and lesion angulation of 1.4 (1 = 45 degrees lesion bend). In 88%, the device was the primary catheter used and in 6%, it was chosen when another system failed. The balloon was able to successfully cross 94% of all lesions attempted. Six lesions were crossed and dilated but significant residual stenoses remained. There were no significant device malfunctions, or angiographic or clinical complications. This feasibility evaluation of this new fixed wire system yielded excellent angiographic results. Although not a comparative study, this analysis suggests that this new generation of angioplasty catheter may improve the safety and efficacy of complex coronary angioplasty.

Torsades de pointes occurring in association with terfenadine use.

Torsades de pointes is a form of polymorphic ventricular tachycardia that is associated with prolongation of the QT interval. Although found in many clinical settings, torsades de pointes is most often drug induced. This report describes the first association (exclusive of drug overdose) of symptomatic torsades de pointes occurring with the use of terfenadine in a patient who was taking the recommended prescribed dose of this drug in addition to cefaclor, ketoconazole, and medroxyprogesterone. Measured serum concentrations of terfenadine and its main metabolite showed excessive levels of parent terfenadine and proportionately reduced concentrations of metabolite, suggesting inhibition of terfenadine metabolism. We believe that a drug interaction between terfenadine and ketoconazole resulted in the elevated terfenadine levels in plasma and in the cardiotoxicity previously seen only in cases of terfenadine overdose.

The use of temporary transvenous pacing catheters during percutaneous transluminal coronary angioplasty.

The use of temporary transvenous pacemakers during percutaneous transluminal coronary angioplasty (PTCA) over a 7(1/2)-month period at our institution was studied retrospectively. During that time, 379 patients underwent PTCA with temporary prophylactic pacemakers in place; 398 patients underwent PTCA without prophylactic pacemakers. We examined factors such as the necessity for emergent pacemaker placement, frequency of pacing during angioplasty, indications for pacing, effectiveness of the type of pacemaker inserted, and complications associated with pacemaker placement. Pacing was indicated in 40 of the 379 patients with prophylactic pacemakers; in only 1 of the 398 patients without prophylactic pacemakers was emergent pacing required for hemodynamic instability. In the patients with prophylactic pacemakers, pacing was initiated during the procedure for 32 patients with transient hemodynamically insignificant bradycardia, 3 patients with sustained bradycardia or heart block, and 5 patients with acute vessel occlusion and associated hypotension or bradycardia, or other episodes of hemodynamic instability. Thus, in only 8 of the 379 patients was pacing instituted for something other than hemodynamically insignificant bradycardia, and in only 5 of the 379 patients was it initiated for hemodynamic instability. The overall incidence of pacing for hemodynamic instability was 6 of 777 (0.8%). The pacing catheters inserted (379 prophylactic and 1 emergent) include #7 Pacewedge (42%), #6 bipolar (29%), #7 Myler (18%), and #7 Zucker (11%). Pacing thresholds were tested in 300 patients. The Pacewedge balloon-tipped pacing catheters had a significantly higher (p < 0.001) pacing threshold for right ventricular capture than the other (non-balloon) pacing catheters used. Two cases of sustained ventricular dysrhythmia were attributed to placement of stiff pacing catheters. No other pacemaker-related complications occurred. From these data we conclude that although there are few complications associated with the prophylactic placement of pacing catheters for PTCA, the need for cardiac pacing for hemodynamic instability during PTCA is low.

Percutaneous transluminal coronary angioplasty: a review of current balloon dilatation systems.

The interventional cardiologist is faced with an expanding armamentarium for performing percutaneous transluminal coronary angioplasty (PTCA). Because of rapid advances in technology, new devices are produced on a regular basis, making it difficult to maintain a working knowledge of what is available. Although several excellent textbooks about PTCA have been written, descriptions of available equipment are usually obsolete by the time publication occurs. In order to provide succinct specifications of equipment, we have documented data on balloon catheters, guiding catheters, and guidewires. This information may be useful in the selection of appropriate equipment for PTCA procedures. In addition, the publication of such data in a monthly periodical may provide a more current overview of equipment; information may be occasionally updated as new equipment is released.