Risks of valve replacements in young women.

Attempts to evaluate performance of cardiac valves by retrospective analysis are notoriously difficult because of the complexity associated with preoperative illnesses, types of replacement valves available or used, use of anticoagulant medications in some but not all patients, and a myriad of other differences. When a diverse group of women having multicultural backgrounds receive valves under various circumstances and at various intracardiac locations over an interval of ≥20 years, the difficulty of showing by rigorous statistical techniques that differences in individual outcomes are related to demonstrable or predictable circumstances relating to the valve is very great. Nevertheless, Dr North and her associates1 have carefully analyzed their data with 93% complete follow-up in 232 patients who received 323 valves between 1972 and 1992 and have presented …