A new staging system using right atrial strain in patients with immunoglobulin light‐chain cardiac amyloidosis
Authors: Usuku Hiroki , Yamamoto Eiichiro , Sueta Daisuke , Shinriki Rumi , Oike Fumi , Tabata Noriaki , Ishii Masanobu , Hanatani Shinsuke , Hoshiyama Tadashi , Kanazawa Hisanori , Arima Yuichiro , Takashio Seiji , Kawano Yawara , Oda Seitaro , Kawano Hiroaki , Ueda Mitsuharu , Tsujita Kenichi 
Published: February 2024

Aims

There are minimal data on the prognostic impact of right atrial strain during the reservoir phase (RASr) in patients with immunoglobulin light‐chain (AL) cardiac amyloidosis.

Methods and results

Among 78 patients who were diagnosed with AL cardiac amyloidosis at Kumamoto University Hospital from 2007 to 2022, 72 patients with sufficient two‐dimensional speckle tracking imaging data without chemotherapy before the diagnosis were retrospectively analysed. During a median follow‐up of 403 days, 31 deaths occurred. Age and the rate of male sex were not significantly different between the all‐cause death group and the survival group (age, 70.4 ± 8.8 years vs. 67.0 ± 10.0 years, P = 0.14, male sex, 65% vs. 66%, P = 0.91). The estimated glomerular filtration rate (eGFR) was significantly lower, and B‐type natriuretic peptide (BNP) and high sensitivity cardiac troponin T (hs‐cTnT) were significantly higher, in the all‐cause death group versus the survival group (eGFR, 48.2 ± 21.0 mL/min/1.73 m2 vs. 59.4 ± 24.4 mL/min/1.73 m2, P < 0.05, BNP, 725 [360–1312] pg/mL vs. 123 [81–310] pg/mL, P < 0.01, hs‐cTnT, 0.12 [0.07–0.18] ng/mL vs. 0.05 [0.03–0.08] ng/mL, P < 0.01). Left ventricular (LV) global longitudinal strain (GLS) (LV‐GLS), left atrial strain during the reservoir phase (LASr), right ventricular GLS (RV‐GLS), and RASr were significantly lower in the all‐cause death group versus the survival group (LV‐GLS, 8.5 ± 4.3% vs. 11.8 ± 3.8%, P < 0.01, LASr, 8.8 ± 7.1% vs. 14.3 ± 8.1%, P < 0.01, RV‐GLS, 11.6 ± 5.1% vs. 16.4 ± 3.9%, P < 0.01, RASr, 10.2 ± 7.3% vs. 20.7 ± 9.5%, P < 0.01). RASr was significantly associated with all‐cause death after adjusting for RV‐GLS, LV‐GLS and LASr (hazard ratio [HR]: 0.91, 95% confidence interval [95% CI]: 0.83–0.99, P < 0.05). RASr and log‐transformed BNP were significantly associated with all‐cause death after adjusting for log‐transformed troponin T and eGFR (RASr, HR: 0.93, 95% CI: 0.87–1.00, P < 0.05; log‐transformed BNP, HR: 2.10, 95% CI: 1.17–3.79, P < 0.05). The optimal cut‐off values were RASr: 16.4% (sensitivity: 66%, specificity: 84%, area under curve [AUC]: 0.81) and BNP: 311.2 pg/mL (sensitivity: 83%, specificity: 78%, AUC: 0.82) to predict all‐cause mortality using ROC analysis. Kaplan–Meier analysis revealed that patients with low RASr (<16.4%) or high BNP (>311.2 pg/mL) had a significantly high probability of all‐cause death (both, P < 0.01). We devised a new staging score by adding 1 point if RASr decreased or BNP levels increased more than each cut‐off value. The HR for all‐cause death using score 0 as a reference was 5.95 (95% CI: 1.19–29.79; P < 0.05) for score 1 and 23.29 (95% CI: 5.37–100.98; P < 0.01) for score 2.

Conclusions

The new staging system using RASr and BNP predicted prognosis in patients with AL cardiac amyloidosis.