Ventilatory efficiency in cardiac amyloidosis—A systematic review and meta‐analysis

Figures

• 

  FIGURE 1. Flowchart of the study selection process. The flowchart in Figure 1 illustrates the study selection process for identifying studies relevant to cardiopulmonary exercise testing (CPET) in cardiac amyloidosis. Out of 85 initially identified records, 37 were excluded based on title screening, and 20 were excluded as off‐topic after screening articles. From 28 articles identified based on titles and abstracts, full texts were screened, resulting in the exclusion of five studies due to potential cohort overlap and six studies for missing key CPET variables. Ultimately, 17 studies were included in the final analysis. Of the 17 included studies three studies had to be excluded after subgroup analysis due to submaximal exercise and short exercise duration (8 minutes). N, number of studies.

• 

  FIGURE 2. Comparative analysis of ATTR versus AL patients. Figure 2 contains two forest plots comparing patients with ATTR and AL. (a) Compares mean age, showing that ATTR patients are significantly older by 9.0 years (95% CI: 0.4–17.6, p = 0.04), with high variability between studies (I 2 = 87.9%). (b) Compares VE/VCO2 slope, indicating slightly reduced ventilatory efficiency in AL patients, with a mean difference of 2.5 (95% CI: 0.2–4.8, p = 0.03) and low variability (I 2 = 0%). Each study is represented by a square (mean difference) and horizontal line (confidence interval), while the diamond at the bottom shows the pooled overall estimate. AL, light chain amyloidosis; ATTR, transthyretin amyloidosis; Chi2, chi‐squared statistic; CI, confidence interval; df, degrees of freedom; I 2, heterogeneity index; MD, mean difference; SD, standard deviation; Tau2, between‐study variance; VE/VCO₂, ventilation to carbon dioxide production ratio.

• 

  FIGURE 3. Effect of exercise modality on peak VO2. Figure 3 shows a forest plot, that summarizes the effect of exercise modality on peak VO2 during CPET, comparing treadmill, upright, and semi‐recumbent cycle ergometry. Treadmill testing yielded the lowest peak VO2. Each study's contribution is shown by a square (mean VO2) and horizontal line (confidence interval), with pooled subgroup means represented by diamonds. CI, confidence interval; I 2, heterogeneity; MRAW, mean random effects model; p, probability value; RE, random effects; VO₂, oxygen uptake; τ 2, tau‐squared (between‐study variance); χ 2, chi‐squared (test of heterogeneity).