Prospective proof of concept study on the utility of integrated transthoracic and transesophageal aortic stenosis assessment

OBJECTIVES: This study sought to analyze the prognostic value and technical feasibility of an integrated echo method (IEM) combining transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) data vs TTE alone in the assessment of aortic stenosis (AS).

BACKGROUND: TTE has limitations in AS assessment which can be partially overcome by complementary TEE.

METHODS: Between 2016-2017, 81 consecutive patients with at least moderate AS were enrolled in our study. Immediately following a baseline TTE, a TEE study was performed and classification was performed by TTE and by IEM. AS was classified as moderate, or severe High-Gradient (HG), Low-EF LF-LG (Low-Flow Low-Gradient), Paradoxical LF-LG (PLFLG), and NF-LG (Normal-Flow Low-Gradient). Based on conservative vs invasive (actionable) treatment implication, AS types were lumped into Group-A (Moderate AS and NFLG), and Group-B (HG, Low-EF LF-LG, and PLFLG). Survival under medical therapy was determined. RESULTS: In 63 included patients, dichotomous AS classification was discordant in 15.9% of the patients with the two methods, with a relative risk of 1.55 of upgrade re-classification with IEM (p<0.001). The optimal cut-off value of TTE-determined AVA for TTE dichotomous AS classification was 0.82 cm2, yielding a respective sensitivity of 75% and specificity of 87% vs an IEM-determined optimal AVA cut-off value of 0.92 cm2 for IEM classification, yielding a respective sensitivity of 84.4% and specificity of 76%. During a median time of 9 months (quartiles 2.4-22 months) of follow-up under medical treatment, Group-B patients had a worse survival than Group-A patients, with additional independent prognostic value for Group A/B dichotomization by IEM in Group-A (non-actionable) TTE-defined patients after multivariable adjustment (hazard ratio 5.3, confidence interval 1.39-20.3, p value=0.015).

CONCLUSIONS: IEM assessment cannot replace TTE for primary clinical decision-making, but its usage in patients with "moderate to severe" AS can improve detection of patients who may benefit from early invasive therapy.