MPO and aortic valve stenosis: The proportion was significantly higher in MPO-AAV patients (28.9%) than in control patients (15.7%) (p = 0.006) (Table 2); 60.7%, 14.3%, and 25.0% of AS patients with MPO-AAV and 75.0%, 16.7%, and 8.3% of control patients were classified into the mild, moderate, and severe categories, respectively.