When to Intervene in Asymptomatic Severe Aortic Stenosis

 The Debate: Early Intervention vs. Watchful Waiting

The management of asymptomatic severe aortic stenosis (AS) has evolved significantly following the EARLY TAVR trial results. 

At the 2025 EAPCI Summit, experts debated whether to intervene early or maintain close surveillance in these patients.

What EARLY TAVR Showed

The EARLY TAVR trial demonstrated that early TAVR reduced the composite endpoint of death, stroke, or unplanned cardiovascular hospitalization by 50% compared to clinical surveillance (26.8% vs. 45.3%, HR 0.50, P0.001). [1] Notably, within 6 months, one in four patients in the surveillance group developed symptoms requiring intervention, and by 2 years, over 70% had undergone valve replacement. [1]

Patients who waited for symptoms experienced declining quality of life before intervention, and many presented with advanced symptoms—including acute valve syndrome with NYHA class III-IV symptoms or syncope—which was associated with worse outcomes, particularly higher stroke rates. [2]

The Case for Early Intervention

Cardiac damage accumulates unpredictably during the asymptomatic phase. The EARLY TAVR trial showed that early intervention preserved left ventricular and left atrial health better than surveillance, with 48.1% maintaining integrated LV health at 2 years versus 35.9% in the surveillance group (P0.001). [1][3]

The AVATAR trial's extended follow-up similarly demonstrated that early surgical AVR reduced the composite endpoint by 58% (HR 0.42, P=0.002), with significant reductions in both mortality and heart failure hospitalizations. [4]

The Case for Watchful Waiting

Personalized risk stratification is essential. The EVOLVED trial, which carefully phenotyped patients with myocardial fibrosis using MRI, showed no significant difference in the primary composite endpoint between early intervention and conservative management, though hospitalization rates were lower with early intervention. [5]

Importantly, mortality rates were similar across treatment strategies in most trials, suggesting that with careful surveillance, watchful waiting remains safe for appropriately selected patients. [1]

What About Biomarkers?

Contrary to expectations, NT-proBNP and troponin levels did not reliably identify which asymptomatic patients benefit most from early intervention. While elevated biomarkers predicted higher event rates overall, the relative benefit of early TAVR was consistent—and sometimes greater—in patients with lower biomarker levels. [6] This suggests limited value for single biomarker measurements in timing decisions.

Updated European Guidelines

The 2025 European guidelines have evolved to recommend considering intervention in asymptomatic patients with:

• High-gradient AS with severe calcification and low surgical risk

• Elevated BNP/NT-proBNP attributable to AS

• LVEF 55% attributable to AS (previously 50%)

• Sustained blood pressure fall >20 mmHg on exercise testing

• Vmax progression ≥0.3 m/s per year

The emphasis has shifted toward personalized medicine rather than rigid cutoffs. [7]

Practical Considerations

Context matters. In healthcare systems with long waiting lists or limited follow-up capacity, earlier intervention may be prudent even for asymptomatic patients. Conversely, in settings with robust surveillance programs, watchful waiting with careful monitoring remains reasonable for selected low-risk patients.

The unpredictability of AS progression—with some patients rapidly developing acute valve syndrome—argues for close surveillance intervals and low thresholds for intervention when any concerning features emerge.

The Bottom Line

The debate reflects a shift from "whether" to "when" to intervene in asymptomatic severe AS. While early intervention reduces hospitalizations and preserves cardiac function, careful surveillance remains viable for appropriately selected patients. The key is individualized decision-making that considers patient preferences, healthcare system capabilities, and evolving risk markers—recognizing that AS progression is unpredictable and cardiac damage, once established, may be irreversible.