From grip to gait: handgrip strength and chair rise test predict six minute walk distance in cardiac amyloidosis

Background and Purpose Cardiac amyloidosis (CA) is a progressive infiltrative cardiomyopathy that often manifests as heart failure accompanied by skeletal muscle weakness and reduced functional capacity. The six-minute walk test (6MWT) is a standard measure of exercise tolerance in this population, but simpler assessments may also capture functional status in patients with neuropathy and lower extremity conditions, and be suitable for telemedical application. We aimed to investigate the associations between handgrip strength (HG), the five-times chair rise test (5CRT), and 6MWT distance in a real-world sample of patients diagnosed with CA. Methods This cross-sectional analysis included ambulatory patients presenting at a tertiary care hospital, with biopsy proven or algorithmically diagnosed CA. All patients underwent standardized evaluation including laboratory tests, echocardiography, a 6MWT conducted in 15 m corridor, HG measured with a hydraulic dynamometer and 5CRT performed from a chair without armrests with arms crossed. According to the European consensus on definition and diagnosis of sarcopenia, low HG was defined as <27 kg for men and <16 kg for women, low 5CRT was defined as > 15 sec to complete five rises. Mean 6MWT distances were compared across performance groups using ANOVA, and age- and height-adjusted linear regression assessed the independent associations of HG and 5CRT with 6MWT distance. Results We studied 148 patients with CA; 114 (77%) had transthyretin amyloidosis, 32 (21.6%) had light-chain amyloidosis, 1 (0.7%) had serum amyloid A amyloidosis and 1 (0.7%) had unclear subtype. Mean (SD) age was 77.5 (12.1) years, 113 (76.4%) were men, mean eGFR was 55 (21) ml/min/1.73m², median (quartiles) NT-proBNP was 1865 (790, 3906) pg/ml, median troponin-T was 40 (26, 58) pg/ml, 19 (13%) had a New York Heart Association (NYHA) functional class I, 65 (45%) had NYHA II, 60 (42%) had NYHA III. The mean 6MWT distance was 349 (122) m, 53 (36%) had low HG, and 93 (63%) had low 5CRT. Patients with low HG walked significantly shorter distances than those with normal HG (mean 290 m vs. 381 m, p < 0.001), and those with low 5CRT likewise covered less distance than their counterparts with normal 5CRT (293 m vs. 425 m, p < 0.001). In multivariable models adjusted for age and height, low HG was associated with a 77 m reduction in 6MWT distance (β = −82 m; 95 % CI −124 to −40; p < 0.001), and low 5CRT with a 126 m reduction (β = −126 m; 95 % CI −161 to −90; p < 0.001). Conclusions In patients with CA, simple muscle strength tests—handgrip strength and the chair rise test—are strongly associated with six-minute walk capacity. Low performance on these tests identifies individuals with diminished functional capacity and may serve as a practical surrogate for more resource-intensive walk test assessments. Further studies should explore whether these measures correlate with patient reported outcomes and longer-term prognosis.