Abstract
Aortic stenosis (AS) has a prevalence of 0.4% in the general population and about 1.7% in people >65 years. One in eight adults >75 years has significant AS; of these, about 30%-50% is asymptomatic. 1 In the management of severe AS, the current practice is to recommend aortic valve surgery/catheter-based valve replacement based on symptom status, left ventricular ejection fraction, exercise testing, or the presence of concomitant lesions needing surgery. AHA Clinical Practice Guidelines 2021 recommended AVR for asymptomatic AS if LVEF is less than 50%, when symptoms appear during exercise testing, or if the patient is going for cardiac surgery due to any other indication (class I). However, when there is a fall of 10 mmHg in systolic blood pressure on exercise testing or if a low surgical-risk patient presents with very severe AS (defined as peak aortic jet velocity >5 m s−1), or an increase in peak aortic jet velocity >0.3 m annually or BNP levels threefold the upper limit of normal, AVR may be considered (class IIA). 2
The symptoms of AS in deconditioned elderly persons can be vague and non-specific. In these patients, the problems in other systems—musculoskeletal, neurological, respiratory, hearing, vision, or cognitive function—can influence mobility and symptoms. The presence of significant AS may be missed. The LVEF has its own limitations of accuracy and may be influenced by concentric LVH, as seen in severe AS. It needs to be highlighted that significant cardiac damage occurs even before symptoms appear in severe AS. The potential benefit of earlier aortic valve surgery or TAVI even in asymptomatic patients is suggested by many studies published earlier as well as a few recent trials, RECOVERY and early TAVI. In the early TAVI trial, on randomization of 901 patients in a 1:1 ratio, the transcatheter valve implantation strategy had proven to be superior to conventional six-monthly clinical surveillance in reducing death, stroke, or unplanned hospitalization for cardiac events. These trials have confirmed that early aortic valve intervention prevents further cardiac damage and improves survival. 3
Non-invasive means to guide stratification mainly include global longitudinal strain, myocardial work index, assessment of fibrosis on cardiac MRI, and elevation of biomarkers. In the evaluation of ischemic heart disease, heart failure, LV hypertrophy, valvular heart disease, and cardiotoxicity of oncological drugs, GLS is superior to EF measurement in the assessment of LV systolic dysfunction even in the subclinical phase and has shown excellent reproducibility across different vendors.4, 5 Its superior and independent prognostic prediction in various cardiac conditions compared to EF was well-described. 6 There is equally promising data emerging on the incremental value of biomarkers that reflect ventricular remodeling, hypertrophy, inflammation, or fibrosis in clinical decisions in deciding the time to intervene. The study—Global longitudinal strain imaging in detection of subclinical left ventricular systolic dysfunction in patients with asymptomatic severe AS—by Dinaraj et al., published in this issue, makes an interesting reading. The authors endorsed the use of left ventricular global longitudinal strain in the detection of subclinical LV dysfunction in severe asymptomatic AS. They also observed a linear relation with biomarkers.
For sure, the newer data will lower our threshold for surgery or intervention in the management of patients with asymptomatic AS. Exciting days are ahead with the idea of preemptive transcatheter aortic valve replacement in asymptomatic patients with moderate to severe AS with normal EF but deranged GLS and/or raised BNP levels or fibrosis on cardiac MRI. However, what criteria have to be followed to recommend AVR/TAVI in patients with asymptomatic AS is yet to be refined.
