Prevalence and Outcomes of Low‐Gradient Severe Aortic Stenosis—From the National Echo Database of Australia

Abstract

Background The prevalence and outcomes of the different subtypes of severe low‐gradient aortic stenosis (AS) in routine clinical cardiology practice have not been well characterized. Methods and Results Data were derived from the National Echocardiography Database of Australia. Of 192 060 adults (aged 62.8±17.8 [mean±SD] years) with native aortic valve profiling between 2000 and 2019, 12 013 (6.3%) had severe AS. Of these, 5601 patients (47%) had high‐gradient and 6412 patients (53%) had low‐gradient severe AS. The stroke volume index was documented in 2741 (42.7%) patients with low gradient; 1750 patients (64%) with low flow, low gradient (LFLG); and 991 patients with normal flow, low gradient. Of the patients with LFLG, 1570 (89.7%) had left ventricular ejection fraction recorded; 959 (61%) had paradoxical LFLG (preserved left ventricular ejection fraction), and 611 (39%) had classical LFLG (reduced left ventricular ejection fraction). All‐cause and cardiovascular‐related mortality were assessed in the 8162 patients with classifiable severe AS subtype during a mean±SD follow‐up of 88±45 months. Actual 1‐year and 5‐year all‐cause mortality rates varied across these groups and were 15.8% and 49.2% among patients with high‐gradient severe AS, 11.6% and 53.6% in patients with normal‐flow, low‐gradient severe AS, 16.9% and 58.8% in patients with paradoxical LFLG severe AS, and 30.5% and 72.9% in patients with classical LFLG severe AS. Compared with patients with high‐gradient severe AS, the 5‐year age‐adjusted and sex‐adjusted mortality risk hazard ratios were 0.94 (95% CI, 0.85–1.03) in patients with normal‐flow, low‐gradient severe AS; 1.01 (95% CI, 0.92–1.12) in patients with paradoxical LFLG severe AS; and 1.65 (95% CI, 1.48–1.84) in patients with classical LFLG severe AS. Conclusions Approximately half of those patients with echocardiographic features of severe AS in routine clinical practice have low‐gradient hemodynamics, which is associated with long‐term mortality comparable with or worse than high‐gradient severe AS. The poorest survival was associated with classical LFLG severe AS.

Surgical aortic valve replacement etiologies, hemodynamics, and outcomes in 1346 patients from the Malaysian heart centre

“…Low gradient severe aortic stenosis may arise in patients with inherently small aortic annuli or low forward stroke volume due to poor systolic function, high arterial afterload, or small left ventricular chamber size [ 13 ]. In this study, looking at severe AS (isolated or mixed), 31% (218/704) had low-gradient severe AS, which is less than the most recent study in Australia showing that half of severe AS cases have low-gradient hemodynamics [ 14 ]. This is most likely due to less recognition and treatment for this confusing entity.…”

Transcatheter Aortic Valve Replacement Improves Quality of Life and Ventricular Function With Low-Flow/Low-Gradient Aortic Stenosis

“…It is important to note that conservative management of these patients has been associated with a dismal prognosis. Snir et al 9 reported that patients with classic low-flow low-gradient D2 AS with no procedural intervention had the highest 1-year and 5-year mortality compared with those with D1 and D3 AS at 30.5% and 72.9%, respectively. 9 Once patients develop symptomatic AS, mortality is >50% at 2 years unless valve replacement is performed.…”

“…Snir et al 9 reported that patients with classic low-flow low-gradient D2 AS with no procedural intervention had the highest 1-year and 5-year mortality compared with those with D1 and D3 AS at 30.5% and 72.9%, respectively. 9 Once patients develop symptomatic AS, mortality is >50% at 2 years unless valve replacement is performed. 8 Long-term predictors of mortality for patients with low-flow/low-gradient AS include chronic obstructive pulmonary disease, residual moderate to severe mitral regurgitation, and anemia.…”

“…Recent reports have shown that patients with classic low-flow/low-gradient D2 AS carry the highest 1-year and 5-year mortality at 30.5% and 72.9%, respectively, compared with the other 2 subtypes in the absence of surgical intervention. 9 Mortality rates as high as 70% at 2 years have been reported for symptomatic patients with nonoperative management. 5 – 7 , 10 Patients with D2 subtype also exhibits significantly worse 1-year rates of mortality and major adverse cardiac and cerebral events following TAVR than those with D1 and D3 subtypes.…”

Potential role of conventional and speckle-tracking echocardiography in the screening of structural and functional cardiac abnormalities in elderly individuals: Baseline echocardiographic findings from the LOOP study

“…However, it should be noted that significant AS was not frequently observed in this study (0.90%). In fact, it was less frequently observed compared to the National Echocardiographic Database of Australia (NEDA) which reported severe AS in 6.3% [ 52 ]. The discrepancy may rely on the fact that NEDA represents a clinical registry, meaning they reported findings from echocardiograms performed for a clinical indication.…”