Tracheal and bronchial cartilaginous rings: warfarin sodium-induced calcification.

Progressive calcification of the cartilaginous rings (CCR) of the trachea and bronchi has been observed in patients undergoing prolonged prophylactic anticoagulant therapy with warfarin sodium. The purpose of this study was to validate the relationship of warfarin sodium and CCR, as well as to present the appearance and sex and age distribution of the normal degenerative CCR seen in the elderly. Chest radiographs were scrutinized for evidence of CCR in 92 patients who underwent warfarin sodium therapy and in 105 patients used as a control group. CCR was classified as not present (scored as 0), subtle (scored as 1), and extensive (scored as 2). In the warfarin sodium study group, 47% of patients (43 of 92) exhibited level 1 or level 2 CCR. This proportion was 19% (20 of 105) in the control group. The difference was statistically significant (P less than .001). A significant positive correlation (P less than .001) was also present between the duration of warfarin sodium therapy and increased levels of CCR.