Left atrial function and left atrioventricular coupling index in patients with cardiac amyloidosis

Abstract Background/Introduction Cardiac amyloidosis (CA) should be suspected in patients with unexplained tickened interventricular septum (IVS ≥ 12mm) and one or more red flags. Among cardiac manifestations the presence of heart failure with preserved ejection fraction (HFpEF) and sometimes with mid-range ejection fraction (HFmEF) should be considered. Multiparametric echocardiographic scores (such as IWT score) exist to discriminate the presence of CA in patients with left ventricular hypertrophy. This score doesn’t include left atrial function. Amyloid accumulates in all cardiac structures (also in the atrial wall) altering its function. Purpose to assess left atrial function and left atrioventricular coupling index in patients with HFpEF or HFmEF and cardiac amyloidosis. Methods a case-control study was conducted enrolling 50 patients with CA diagnosed in accordance with recent ESC position paper and 50 patients with HFpEF and HFmEF and IVS ≥ 12 mm. Speckle tracking echocardiography was performed in all patients; IWT score was assessed in all patients. Left atrial (LA) function was analyzed measuring reservoir LA strain (PALS), LA contraction strain (PACS), LA stiffness (LASI= E/e’ average/PALS); LA reservoir work (LAWR= PALS x LA reservoir volume). Left atrioventricular coupling index (LACI) was also measured as the ratio of LA end-diastolic volume divided by left ventricular (LV) end-diastolic volume. Results we found that patients with CA were significantly older and male (p-value < 0.05) compared to HF patients; atrial fibrillation significantly predominated in patients with CA (p-value 0.0045). Natriuretic peptides and troponin were significantly increased in CA patients (p-value 0.04 and p-value 0.01). Analyzing echocardiographic data: LV global longitudinal strain (-12±3.9 % vs -12.87 ±4.3%) and LVEF (52.12 ± 8.15 % vs 50±7.68 %) did not differ significantly between groups; relative wall tickness (RWT) was significantly increased in CA patients (p-value < 0.0001), left atrial function and LACI were significantly impaired in patients with CA. PALS, PACS and LAWr were significantly reduced in patients with CA and they were predictors of CA. Also LA indexed volume, LASI and LACI were significantly increased in patients with CA (p-value < 0.05). Analyzing ROC curve, we found that a value of LASI > 1,1% (AUC 0.86), PALS < 5.5 % (AUC 0.81) and LAWr < 103 %/ml (AUC 0.82) were the best predictors of CA in patients with HF; also PACS < 0.9% (AUC 0.79) or absence of atrial contraction and LACI > 56% (AUC 0.73) were found to be good predictors of CA. Conclusions Left atrial function and left atrioventricular coupling are more impaired in patients with CA than in patients with HF alone. LACI and left atrial function could aid to diagnose CA in patients with HFpEF or HFmEF with left ventricular hypertrophy, especially if IWT score is between 2 and 7. To confirm the proposed cut-off values larger studies are needed.