RESUMEN
BACKGROUND AND AIM OF THE STUDY: Cardiologists continue to struggle with the prognosis and significance of low-gradient, severe aortic stenosis (AS) with preserved ejection fraction (EF). Conflicting data makes more substantive decisions challenging. The study aim was to determine the prognosis and significance of severe AS by reviewing index cases from the authors' echocardiography laboratory. METHODS: The study included 302 patients with AS and with aortic valve area (AVA) ≤1.0 cm2 who were identified from the echocardiography database between 2010 and 2011. AS was subdivided into four types based on AVA and mean pressure gradient (PG): (i) PG-matched, severe AS (AVA ≤1.0 cm2 and mean PG ≥40 mmHg; n = 143); (ii) low-PG, severe AS (AVA ≤1.0 cm2, mean PG <40 mmHg, and reduced EF <50%; n = 52); (iii) low-PG, severe AS (AVA ≤1.0 cm2, mean PG <40 mmHg, preserved EF ≥50%; n = 107); and patients with moderate AS (mean PG >25 mmHg and AVA ≥1.0 cm2; n = 104). RESULTS: Among patients medically managed, those with low-PG severe AS and a reduced EF had the worst outcome. Compared to low-PG severe AS with EF ≥50%, patients with a low-PG and severe AS with EF <50%, and with matched-PG severe AS, had an increased risk of death (p <0.001 and p = 0.052, respectively). For gradient-matched severe AS, those patients who were unoperated had a more than five-fold mortality risk compared to those who underwent surgery [Hazard Ratio (HR): 5; p <0.001]. Similarly, among patients with low-PG severe AS with EF ≥50%, those medically managed had a threefold greater mortality risk compared to those who underwent surgery (HR: 3.3; p = 0.002). CONCLUSIONS: Patients with low-PG severe AS and a preserved EF have a worse survival than those with moderate AS, but survived better than those with gradient-matched severe AS.