The Flow Rate in Patients With Low-Gradient Aortic Stenosis

TL;DR

This study shows that flow rate is a better predictor of mortality in older patients with low-gradient aortic stenosis than stroke volume index.

Contribution

The study introduces flow rate as a novel and more accurate predictor of mortality in low-gradient aortic stenosis patients.

Findings

A flow rate < 210 ml/s was linked to a 66.7% three-year mortality rate.

Stroke volume index < 35 ml/m² was not associated with three-year mortality.

Flow rate better reflects flow status and prognosis in older patients with low-gradient aortic stenosis.

Abstract

Purpose: The decision to assess the severity and determine the ideal timing of intervention for low-gradient aortic stenosis poses a greater challenge. Recently, a novel method for determining the flow status of patients with aortic stenosis has been introduced, utilizing flow rate measurements. In this study, we investigated whether the flow status of patients with low-gradient aortic stenosis is linked to mortality within a three-year timeframe.

Methods: Twenty-nine patients diagnosed with low-gradient aortic stenosis and valve area ≤ 1 cm were identified during 2010-2015. Each patient's flow rate across the aortic valve was computed, and the study scrutinized echocardiographic parameters to ascertain their correlation with mortality over a three-year timeframe.

Results: We observed that among patients with low-gradient aortic stenosis and a valve area of ≤1 cm, a decreased flow rate across the aortic valve emerged as an independent predictor of mortality. A flow rate < 210 ml/s was linked with a three-year mortality rate of 66.7%, whereas a low stroke volume index < 35 ml/m² did not show an association with three-year mortality. This observation might be attributed to the smaller body sizes prevalent among these older patients, particularly females, which could influence the calculation of the stroke volume index.

Conclusion: In older patients with low-gradient aortic stenosis, the flow rate can better reflect flow status than the stroke volume index, and it also suggests a prognostic significance in predicting mortality. Additional studies are warranted to validate these findings across broader patient populations and to assess the potential efficacy of early intervention strategies in this particular patient cohort.

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