Perspective:

Patients with NF-LG severe AS are a challenging cohort to manage, as they do not fit into current guideline recommendations for valve replacement, and yet may have symptoms consistent with AS. While underestimation of gradients on echocardiography can incorrectly suggest this category, NF-LG severe AS is also frequently seen on invasive hemodynamics and is clearly a common patient cohort. This study finds that patients assigned to conservative management by their cardiologist or selected by personal preference have markedly higher rates of mortality even after adjusting for other variables. However, there may be unmeasured variables playing a role in these differences. Among this population that did not meet guideline recommendations for valve replacement, it is not clear why nearly one half were treated with an intervention. These findings support the need for randomized trials to evaluate the role of valve replacement in patients with NF-LG severe AS.