Peak filling rate assessed by myocardial perfusion imaging predicts adverse outcomes in women with chronic coronary syndromes.

BACKGROUND: Diastolic dysfunction may represent an important risk dimension beyond myocardial ischemia and systolic impairment, particularly in women with chronic coronary syndromes (CCS). However, the prognostic value of myocardial perfusion imaging (MPI)-derived diastolic parameters and their potential sex-specific differences remain uncertain. Therefore, this study aimed to evaluate the prognostic significance of single photon emission computed tomography (SPECT) MPI-derived diastolic parameters in patients with CCS without reduced ejection fraction (EF <40%). METHODS: In this retrospective cohort study, data of 1,446 patients undergoing resting MPI were analyzed at the First Hospital of Shanxi Medical University [2016-2021]. The diastolic parameters obtained from MPI included peak filling rate (PFR), mean filling rate over the first third of the end-systole to end-diastole phase (MFR/3), and time to peak filling from end-systole (TTPF). Propensity score matching balanced baseline clinical characteristics between sexes. Multivariable Cox regression evaluated the associations between sex, diastolic parameters, and major adverse cardiovascular events (MACEs). These analyses were further differentiated by total perfusion deficit (TPD) ≥10% and EF ≥50% groups. RESULTS: (I) Over a median 3.05-year follow-up, 519 patients (35.9%) experienced MACE. (II) No statistically significant differences were observed in the predictive value for MACE among PFR, MFR/3, TTPF, and the combination of these three parameters (P=0.956). (III) Reduced PFR independently predicted MACE in women [hazard ratio (HR) 0.61, P=0.028] but not in men (P=0.167). This sex difference persisted in patients with TPD ≥10% (HR 0.36) and EF ≥50% groups (HR 0.57, all P<0.05). CONCLUSIONS: In patients of CCS without reduced EF, MPI-derived PFR demonstrates sex-specific prognostic value, serving as an independent predictor of MACE in women but not men. These findings highlight the potential of diastolic analysis to refine risk stratification in women.