In non-ischaemic cardiomyopathy, higher SRS on 99mTc-MIBI was linked to impaired exercise capacity and a 3.2-fold higher risk of adverse outcomes with PPVO₂ ≤ 60%.
Does myocardial damage assessed by 99mTc-MIBI scintigraphy correlate with impaired exercise capacity and predict adverse clinical outcomes in patients with non-ischaemic cardiomyopathy?
In patients with non-ischaemic cardiomyopathy, myocardial damage assessed by 99mTc-MIBI scintigraphy is associated with impaired exercise capacity and independently predicts poor clinical outcomes.
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Abstract Backgrounds Exercise capacity is an important prognostic factor in patients with heart failure (HF). The percentage of predicted peak oxygen consumption (PPVO₂), an objective measure of exercise capacity assessed by cardiopulmonary exercise testing (CPET), is valuable in predicting HF prognosis. Decreased myocardial uptake on resting technetium-99 m sestamibi (99mTc-MIBI), including a high summed rest score (SRS), reflects myocardial damage and is associated with poor prognosis in ischaemic cardiomyopathy. However, in non-ischaemic cardiomyopathy (NICM), the relationship between decreased 99mTc-MIBI uptake and exercise capacity or prognosis remains unclear. Purpose To investigate whether myocardial damage, assessed by decreased uptake of 99mTc-MIBI, contributes to impaired exercise capacity and adverse clinical outcomes in patients with NICM. Methods We retrospectively analyzed 182 NICM patients (mean age 51.4 ± 14.0 years; 27% female) with a left ventricular ejection fraction 50% who underwent 99mTc-MIBI scintigraphy and CPET during hospitalisation at our hospital between June 2016 and June 2023. Myocardial uptake of 99mTc-MIBI was evaluated using the SRS. Patients were stratified based on PPVO₂ (≤ 60% vs. 60%) to compare patient characteristics, SRS, and clinical outcomes defined as a composite of all-cause death, ventricular assist device implantation and heart transplantation. Results PPVO₂ was ≤ 60% in 74 patients (41%). The SRS was significantly higher in the PPVO₂ ≤ 60% group than in the PPVO₂ 60% group (12 IQR 7-18 versus 8 IQR 5-12, p 0.001). During a median follow-up of 807 days (IQR 359 - 1476), 23 patients (13%) experienced composite outcomes. Higher SRS was significantly associated with worse outcomes (HR 1.102, 95% CI: 1.065 - 1.139, p 0.001). In multivariate cox proportional hazards analysis, which included SRS and PPVO₂ ≤ 60%, SRS remained significant predictors of worse outcomes, along with PPVO₂ ≤ 60% (HR 1.085, 95% CI: 1.048 - 1.123, p 0.001) and PPVO₂ ≤ 60% (HR 3.197, 95% CI: 1.124 - 9.094, p = 0.020). Kaplan-Meier survival curves, stratified by the median SRS value of 9 and a PPVO₂ value of 60%, showed significant overall differences in the risk of composite events (log-rank p 0.001). Among the four groups, patients with low PPVO₂ and high SRS had the highest risk. (Figure) Conclusions Inpatients with non-ischaemic cardiomyopathy, myocardial damage, indicated by decreased uptake of 99mTc-MIBI, was associated with impaired exercise capacity and poor clinial outcomes. In these patinets, assessing myocardial damage by 99mTc-MIBI scintigraphy alongside exercise capacity may contribute to further risk stratification.Kaplan-Meier Survival Curves
Mima et al. (Sat,) reported a other. In non-ischaemic cardiomyopathy, higher SRS on 99mTc-MIBI was linked to impaired exercise capacity and a 3.2-fold higher risk of adverse outcomes with PPVO₂ ≤ 60%.