Synopsis See the table of recommendations for a summary of recommendations from this section and Figure 2 for indications for AVR in patients with AS. These recom- mendations for timing of intervention for AS apply to both SAVR and TAVI. The integrative approach to as- sessing risk of SAVR or TAVI is discussed in Section 2.5. The specific type of intervention for AS is discussed in Section 3.2.4. CLINICAL STATEMENTS AND GUIDELINES Recommendation-Specific Supportive Text 1. In symptomatic patients with severe high-gradi- ent AS (Stage D1), ample evidence demonstrates the beneficial effects of AVR on survival, symp- toms, and LV systolic function.35,41 46 The most common initial symptom of AS is exertional dys- pnea or decreased exercise tolerance. Clinical vigilance is needed to recognize these early symptoms and proceed promptly to AVR. More severe classical symptoms of AS, including HF, syncope, or angina, can be avoided by appropri- ate treatment at the onset of even mild symp- toms. Outcomes after surgical or transcatheter AVR are excellent in patients who do not have a high procedural risk.41,43 45 Surgical series demon- strate improved symptoms after AVR, and most patients have an improvement in exercise toler- ance, as documented in studies with pre- and post-AVR exercise stress testing.41,43 46 Historical observation studies on outcomes in symptomatic patients with severe AS have been confirmed in RCTs comparing TAVI with palliative care in patients with a prohibitive surgical risk. The choice of surgical versus transcatheter AVR for patients with an indication for AVR is discussed in Section 3.2.4.1 3,5,6,12 16,35,42,47 55 2. 