Aortic medial changes associated with bicuspid aortic valve: Myth or reality

OBJECTIVE: To determine whether aortic medial changes are more severe in pa tients who require aortic valve replacement of congenitally bicuspid aortic valves (BAV) than in patients who require replacement of tricuspid aortic valves and acquired valvular disease (AVD). DESIGN: Aortas from autopsies of 24 patients with BAV and 25 with AVD were histologically assessed by two 'blinded' cardiovascular pathologists and an alyzed independently with computer-aided morphometry. The aortic valves wer e examined for valvular fibrosis and calcification. SETTING: The patient population was from a tertiary care facility. PATIENTS: Patients were selected by retrospective review of autopsy records for patient deaths after aortic valve replacement, over the period 1984 to 1995. RESULTS: There were no significant differences in age (P=0.89), sex (P=0.94 ), prevalence of systemic arterial hypertension (P=0.37), valvular degenera tive changes (P=0.10 and P=1.0) or heart weights (P=0.60) between the two g roups. Histological scores for aortic medial degenerative changes including elastic fragmentation, fibrosis and medionecrosis were not statistically d ifferent between the groups. However, morphometry demonstrated less elastic tissue in patients with BAV (P=0.003). CONCLUSION: Routine microscopy show s no significant difference in the degree of aortic medial degenerative cha nges between patients with BAV and AVD. However, morphometry shows less ela stic tissue in the aortas of BAV patients. This may explain the anecdotal i ncrease in aortic fragility and propensity for aortic dissection in these p atients.