Association of Summed Rest Score on Technetium-99m Sestamibi With Exercise Capacity and Incident Adverse Outcomes in Hospitalized Patients With Nonischemic Cardiomyopathy: A Retrospective Analysis.

Mima H; Osaka Graduate School of Medicine Osaka Japan.
Sera F; Ohtani T; Akazawa Y; et al

Journal of the American Heart Association. 15(17):e050214, 2026 Sep.

BACKGROUND: In nonischemic cardiomyopathy, the clinical relevance of
decreased resting myocardial technetium-99m sestamibi (99mTc-MIBI) uptake
regarding exercise capacity and clinical outcomes remains incompletely
understood. We investigated whether decreased 99mTc-MIBI uptake is
associated with impaired exercise capacity and adverse clinical outcomes
in nonischemic cardiomyopathy.

METHODS: We retrospectively analyzed 182 patients (mean age 51.4+/-14.0
years; 27% female) with nonischemic cardiomyopathy and left ventricular
ejection fraction <50% who underwent 99mTc-MIBI scintigraphy and
cardiopulmonary exercise testing from 2016 to 2023. Myocardial uptake of
99mTc-MIBI was evaluated using the summed rest score (SRS). Exercise
capacity was assessed by percentage of predicted peak oxygen consumption
(PPVO2), with <=60% defining impairment.

RESULTS: Seventy-four patients (41%) had PPVO2 <=60% and higher SRS
(median: 12 versus 8; P < 0.001). Higher SRS remained significantly
associated with PPVO2 <=60% after adjustment for relevant clinical
covariates, including brain natriuretic peptide level, left ventricular
ejection fraction, and heart failure duration. Over a median follow-up of
807 days, 23 patients (13%) experienced the composite outcome of all-cause
death, ventricular assist device implantation, or heart transplantation.
Higher SRS was associated with composite outcomes after adjusting for
PPVO2 <=60%. Among the 4 groups stratified by median SRS of 9 and PPVO2 of
60%, patients with high SRS and low PPVO2 had the highest incidence of
adverse events.

CONCLUSIONS: Decreased myocardial 99mTc-MIBI uptake was associated with
impaired exercise capacity and adverse outcomes in patients with
nonischemic cardiomyopathy. Our findings suggest that myocardial injury
assessment using 99mTc-MIBI scintigraphy may provide prognostic
information complementary to exercise capacity.