Introduction: The aim of this study was to assess the contribution of the congenital bicuspid aortic valve (BAV) to the development of acquired aortic valve diseases. Patients who underwent surgery due to left arterial ostium anomaly, BAV was relatively often found. The frequency of BAV occurrence amounts to about 1% (general population). Material and methods: The retrospective analysis comprised 1295 patients, 904 men and 391 women, aged between 17-78, underwent surgery due to aortic or mitral-aortic anomalies (between 1990-1995).Results: We noted BAV in 382 (29.5%) patients. The percentage of BAV patients increased during the following years. BAV was found in 287 men and 95 women (M/W = 3/1), TAV in 617 and 296, respectively (M/W =2/1). The average age of BAV patients was 48.8, and those with TAV Ñ 52.1. Stenosis, insufficiency and combined anomalies occurred in 191 (50%), 54 (14.1%), 137 (35.9%) patients with BAV and in 277 (30.3%), 262 (28.7%), 374 (41%) patients with TAV, respectively - p<0.001. The predominant BAV lesion was cusp calcification comprising the valvular annulus fibrosus, found in 215 cases (56.3%) as compared with 350 TAV patients (38.5%) (p<0.001). In the group with BAV, there were no Marfan syndrome patients. Conclusions: 1. BAV patients are at increased risk for acquired aortic defects. 2. BAV occurs 30 times more frequently in patients who underwent surgery due to acquired aortic valve defects in comparison with the general population.
3. The predominant form of the defect connected with BAV is ostium stenosis. 4. The BAV degeneration rate is much greater than that of TAV. 5. Early BAV detection may improve the prevention of the acquired anomaly.

Keywords: bicuspid aortic valve, tricuspid aortic valve, acquired valve defect, calcification, valvular defect predilection