Characterizing paradoxical low-flow, low-gradient aortic stenosis in contemporary practice
M L Moura, I A Rodrigues, R Teixeira, F M Nunes, F L Sousa, F C Almeida, A Lobo, A Goncalves, M Leite, A I Neves, R Faria, R Fontes-CarvalhoAbstract
Background
Paradoxical low-flow, low-gradient aortic stenosis (PLFLGAS) represents a distinct phenotype of severe aortic stenosis (SAS), characterized by low flow and low transvalvular gradients despite preserved ejection fraction.
Purpose
To describe the demographic profile, clinical characteristics and echocardiographic features of patients with PLFLGAS.
Methods
We conducted a retrospective observational study including all patients diagnosed with SAS by transthoracic echocardiography at our institution between 2012 and 2020. Patients were classified with PLFLGAS if they met the following criteria: aortic valve area ≤1.0 cm², mean transvalvular gradient <40 mmHg, stroke volume index <35 mL/m², and left ventricular ejection fraction ≥50%. Demographic data, cardiovascular comorbidities and echocardiographic parameters were collected. Data distribution was assessed visually. Normally distributed variables were reported as mean ± standard deviation, non-normally distributed variables as median and interquartile range and categorical variables as frequencies and percentages.
Results
Among the 243 patients diagnosed with severe aortic stenosis, 90 (37%) fulfilled PLFLGAS criteria. These were predominantly female (62.2%) with a median age of 78.4 years (IQR 12). Mean body mass index was 28.9 ± 3.9 kg/m². At least one cardiovascular risk factor was present in 85 patients: 88% had hypertension, 74% dyslipidaemia and 40% diabetes mellitus. 16% were active smokers. Coronary artery disease was observed in 29%, previous stroke in 13%, and atrial fibrillation in 46%. Echocardiographic assessment revealed a mean aortic valve area of 0.77 ± 0.13 cm², mean gradient of 26 ± 8 mmHg and median stroke volume index of 32 mL/m² (IQR 6). Mean left ventricular ejection fraction was 58 ± 8%, however global longitudinal strain was frequently impaired (median −14%, IQR 8). Concentric left ventricular hypertrophy was present in 73% of patients. Left atrial enlargement was common (median indexed volume 45 mL/m², IQR 8) and most patients exhibited diastolic dysfunction (median E/E′ 13, IQR 13) and echocardiographic signs of pulmonary hypertension (72%).
Conclusion
PLFLGAS was frequent among patients with SAS and particularly affected elderly women with a high burden of cardiovascular comorbidities and diastolic dysfunction. Impaired global longitudinal strain was common despite preserved ejection fraction and may represent an early marker of myocardial systolic dysfunction in this population.