摘要
Objective:To investigate the prognostic value of myocardial flow reserve (MFR) measured by SPECT myocardial blood flow (MBF) quantitative technique in patients with intermediate stenoses of coronary arteries.Methods:From September 2019 to May 2021, patients with intermediate stenoses (50% to 80%) identified by invasive coronary angiography in Fuwai Hospital, Chinese Academy of Medical Sciences, Fuwai Center China Cardiovascular Hospital, and TEDA International Cardiovascular Hospital were prospectively included. All patients underwent a one-day rest/stress SPECT myocardial perfusion imaging (MPI) and SPECT MBF quantification. The radioactivity distribution of each segment of the MPI bullseye polar maps were obtained according to the standard 5-point method to obtain the summed stress score (SSS) and the summed difference score (SDS) to determine the existence of abnormality. ROC curve analysis was used to obtain the optimal prognostic cut-off value for MFR. The primary endpoint was defined as cardiovascular endpoint events. Survival and prognostic analyses were conducted by Kaplan-Meier method and Cox proportional hazard models. The difference of AUCs was analyzed by Delong test.Results:A total of 314 patients (194 males, 120 females; age (59.4±8.6) years) were enrolled. Over a median follow-up duration of 754 (range: 628-914) d, 54 patients had endpoint events. ROC curve showed that the prediction ability of MFR was significantly better than that of conventional MPI (AUCs: 0.713 and 0.512; z=3.76, P<0.001). The optimal prognostic cut-off value for MFR to predict endpoint events in patients with intermediate stenoses was 2.04. Cox multivariate analysis showed that MFR (hazard ratio ( HR)=0.434, 95% CI: 0.282-0.669, P<0.001) was an independent predictor of endpoint events in patients with intermediate stenoses. Kaplan-Meier survival analysis showed that the prevalence of endpoint events in patients with MFR≤2.04 was significantly higher than that in patients with MFR>2.04 (25.4%(43/169) vs 7.6%(11/145); χ2=21.27, P<0.001). Conclusion:The MFR measured by SPECT MBF quantitative technique has an independent predictive value for cardiovascular endpoint events in patients with intermediate stenoses.
摘要
Objective:To explore the changes of right ventricular myocardial perfusion in pulmonary arterial hypertension (PAH) pig models with a quantitative analysis technique based on dynamic SPECT myocardial perfusion imaging, and analyze the relationship between myocardial blood flow, hemodynamics and right ventricular function.Methods:Eleven Chinese miniature pigs (all males, 6-8 months old) weighing 25-30 kg were selected. The PAH models were established by ligating the main pulmonary artery and embolizing the right lower pulmonary artery. After the models were established, dynamic myocardial perfusion imaging with one-day resting/adenosine stress 99Tc m-methoxyisobutylisonitrile (MIBI) SPECT was performed, and the quantitative parameters of left and right ventricles were obtained, including stress myocardial blood flow (SMBF), rest myocardial blood flow (RMBF) and myocardial flow reserve (MFR: the ratio of stress to rest myocardial blood flow). Right heart catheterization was performed to evaluate the mean pulmonary arterial pressure (mPAP), and the right heart function index tricuspid annular plane systolic excursion (TAPSE) was measured by transthoracic echocardiography. According to TAPSE, animals were divided into right heart function preserved group ( n=5, TAPSE≥17 mm) and right heart dysfunction group ( n=4, TAPSE<17 mm). Pearson correlation analysis and the independent-sample t test were used for data analysis. Results:Nine experimental pig models were established with increased mPAP of (38.1 ± 11.6 ) mmHg (1 mmHg=0.133 kPa). Myocardial perfusion imaging showed clear radiotracer uptake in the right heart and myocardial hypertrophy. There was a significant positive correlation between right ventricular myocardial RMBF ((0.71±0.13) ml·min -1·g -1) and mPAP ( r=0.94, P< 0.001). The SMBF in the decreased right ventricular function group was significantly lower than that in the preserved right ventricular function group ((1.66±0.35) vs (2.24±0.30) ml·min -1·g -1;t=2.68, P=0.032). Conclusion:SPECT myocardial blood flow quantification can be used to evaluate the right ventricular myocardial blood flow in pig models of PAH.