In patients with very severe AS and an aortic velocity 5.0 m/s or mean pressure gradient 60 mmHg, the rate of symptom onset is approxi- mately 50% at 2 years. On multivariable analy- sis of a large cohort of adults with asymptomatic AS (>500 patients), an aortic velocity 5 m/s was associated with a >6-fold increased risk of cardio- vascular mortality (hazard ratio [HR]: 6.31; 95% A randomized trial of SAVR ver- sus continued surveillance showed a significant survival benefit to early surgery in patients with In patients very severe asymptomatic AS and low surgical risk, a decision to proceed with AVR or continue watchful wait- ing takes into account patient age, avoidance of patient prosthesis mismatch, anticoagulation issues, and patient preferences.31 33,39 8. An elevated serum BNP level is a marker of sub- clinical HF and LV decompensation. In a cohort of 387 asymptomatic adults with severe AS, elevated BNP levels were associated with an increased 5-year risk of AS-related events, with a CLINICAL STATEMENTS AND GUIDELINES hazard ratio for a BNP level >300 pg/mL (3 times Serum BNP levels also are predictive of symptom onset during follow-up and persistent symptoms after AVR.36 9. Hemodynamic progression eventually leading to symptom onset occurs in nearly all asymptomatic patients with AS once the aortic velocity reaches 2 m/s. Although the average rate of hemody- namic progression for calcific stenosis of a trileaf- let valve is an increase in aortic velocity of about 0.3 m/s per year, an increase in mean gradient of 7 to 8 mmHg per year, and a decrease in valve per year, there is marked vari- ability between patients in disease progression. Predictors of rapid disease progression include older age, more severe valve calcification, and a faster rate of hemodynamic progression on serial studies. 