Randomized clinical trials in interventional cardiology

Changes in practice patterns are the result of multiple factors including physician experience, participation in live demonstration courses, referral biases and expectations, results of single-center studies, multicenter registries, and randomized clinical trials. The relative importance of each of these components varies substantially. The scientific validity is strongest when supported by randomized trial data, but it must be remembered that these trials can be interpreted in multiple ways depending in part on the biases and experience of the interpreter. This issue has been exemplified by the interpretation of the randomized clinical trials of directional coronary atherectomy (DCA). Interpretation of randomized clinical trials may be difficult. It includes consideration of the design of the trial, the end points used (either single or combined), the power of the study, and the patient population studied. The issue of statistical significance versus clinical significance must also be kept in mind. Recently, equivalence testing has become more sophisticated and more popular. With this design, superiority cannot be proved or assessed; rather, two therapies can be considered equivalent if the difference in outcome falls within predefined boundaries. Usage patterns will then be based on ease of use, patient acceptance, and economic considerations, among others. Recent randomized clinical trials have included DCA, rotational atherectomy, and intracoronary stents.