An alternative method of indexation in aortic stenosis: height-adjusted effective orifice area : An observational prospective study.

BACKGROUND: Although indexing effective orifice area (EOA) by body surface area (BSA) is recommended, this method has several disadvantages, since it corrects by acquired fatty tissue. Our aim was to analyze the value of EOA normalized by height for predicting cardiovascular outcome in patients with aortic stenosis (AS).

METHODS: Patients with AS (peak velocity > 2 m/s) evaluated in our echocardiography laboratory between January 2015 and June 2018 were prospectively enrolled. EOA was indexed by BSA and height. A composite primary endpoint was defined as cardiac death or aortic valve replacement. A receiver operating characteristic curve was plotted to determine the best cutoff value of EOA/height for predicting cardiovascular events.

RESULTS: Four-hundred and fifteen patients were included (52% women, mean age 74.8 ± 11.6 years). Area under the curve was similar for EOA/BSA (AUC 0.75, p < 0.001) and EOA/height (AUC 0.75, p < 0.001). A cutoff value of 0.60 cm2 /m for EOA/height had a sensitivity of 84%, specificity of 61%, positive predictive value of 60% and negative predictive value of 84%. One-year survival from primary endpoint was significantly lower in patients with EOA/height ≤ 0.60 cm2 /m (48 ± 5% vs 91 ± 4%, log-rank p < 0.001) than EOA/height > 0.60 cm2 /m. The excess of risk of cardiovascular events seen in univariate analysis persists even after adjustment for other demonstrated adverse prognostic variables (HR 5.91, 95% CI 3.21-10.88, p < 0.001). In obese patients, there was an excess of risk in patients with EOA/height < 0.60 cm2/m (HR 10.2, 95% CI 3.5-29.5, p < 0.001), but not in EOA/BSA < 0.60 cm2 /m2 (HR 0.14, 95% CI 0.14-1.4, p = 0.23).

CONCLUSIONS: We could identify a subgroup of patients with AS at high risk of cardiovascular events. Consequently, we recommend using EOA/height as a method of indexation in AS, especially in obese patients, with a cutoff of 0.60 cm2/m for identifying patients with higher cardiovascular risk.