Misclassification of Mitral Valve Disease and Rate of Surgical Repair in The Society of Thoracic Surgeons Database.

BACKGROUND: Surgical repair of primary mitral regurgitation (MR) is considered an indicator of quality performance. Therefore, accurate data reporting is critical for quality assessment. During an institutional quality review, MR etiology could not be determined in 40% of operations in The Society of Thoracic Surgeons database entries, and therefore our true repair rate could not be reliably ascertained. Therefore, we reviewed all source documents and echocardiograms to assess our true disease etiology and repair rate.

METHODS: Source records and echocardiograms of all operations performed in a single health care system for a 1-year period were reviewed by an experienced mitral valve surgeon, an echocardiographic core laboratory, and a data manager. Disease etiology and operation were compared with data previously entered in the database by post hoc chart abstraction.

RESULTS: In all, 314 isolated mitral valve operations were performed. The MR was originally classified as primary, 163 (52%); secondary, 22 (7%); rheumatic, 37 (12%); endocarditis, 24 (8%); other, 33 (10%); and unknown, 35 (11%). Reported repair rate for primary MR was 142 of 163 (87.1%). After review, etiology was determined to be primary, 177 (56%); secondary, 33 (11%); rheumatic, 61 (20%); endocarditis, 25 (8%); and others, 18 (5%)-resulting in a change of classification in 99 of 314 patients (31.5%) and a true repair rate for primary MR of 165 of 177 (93.2%).

CONCLUSIONS: Source document and imaging review of mitral valve surgery revealed significant discordance with post hoc chart abstraction methods. A more detailed data entry methodology is necessary to accurately report the true disease etiology and repair rates for primary MR.