Stress myocardial blood flow correlates with ventricular function and synchrony better than myocardial perfusion reserve: A Nitrogen-13 ammonia PET study

Abstract

BackgroundCardiac PET quantifies stress myocardial blood flow (MBF) and perfusion reserve (MPR), while ECG-gated datasets can measure components of ventricular function simultaneously. Stress MBF seems to outperform MPR in the detection of significant CAD. However, it is uncertain which perfusion measurement is more related to ventricular function. We hypothesized that stress MBF correlates with ventricular function better than MPR in patients studied for suspected myocardial ischemia.MethodsWe studied 248 patients referred to a rest and adenosine-stress Nitrogen-13 ammonia PET. We performed a multivariate analysis using systolic function (left ventricular ejection fraction, LVEF), diastolic function (mean filling rate in diastole, MFR/3), and synchrony (Entropy) as the outcome variables, and stress MBF, MPR, and relevant covariates as the predictors. Secondarily, we repeated the analysis for the subgroup of patients with and without a previous myocardial infarction (MI).Results166 male and 82 female patients (mean age 63 ± 11 and 67 ± 11 year, respectively) were included. 60% of the patients presented hypertension, 57% dyslipidemia, 21% type 2 diabetes mellitus, 45% smoking, and 34.7% a previous MI. Mean stress MBF was 1.99 ± 0.75 mL/g/min, MPR = 2.55 ± 0.89, LVEF = 61.6 ± 15%, MFR/3 = 1.12 ± 0.38 EDV/s, and Entropy = 45.6 ± 11.3%. There was a significant correlation between stress MBF (P < .001) and ventricular function. This was stronger than the one for MPR (P = .063). Sex, age, diabetes, and extent of previous MI were also significant predictors. Results were similar for the analyses of the 2 subgroups.ConclusionStress MBF is better correlated with ventricular function than MPR, as evaluated by Nitrogen-13 ammonia PET, independently from other relevant cardiovascular risk factors and clinical covariates. This relationship between coronary vasodilatory capacity and ventricular function is sustained across groups with and without a previous MI.Electronic supplementary materialThe online version of this article (doi:10.1007/s12350-016-0669-y) contains supplementary material, which is available to authorized users.

Ventricular synchrony is not significantly determined by absolute myocardial perfusion in patients with chronic heart failure: A 13N-ammonia PET study

“…This collateral finding partially supports the perception suggested in previous reports of the superiority of sMBF as an absolute PET myocardial perfusion parameter. 14,24 Furthermore, this larger effect of sMBF reflected into the fully adjusted multivariate analysis where a trend towards a significant association with ventricular synchrony was noticed (p = .06), contrary to the multivariate results considering MPR (p = .23). We believe that these effects become readily patent in the pictorial representation of the MACONVA models' results.…”

“…Independent significance of the evaluated predictors was assessed through Pillai's trace criterion with an approximate F statistic. 14…”

“…12 Recently, ventricular mechanical synchrony has been implied as a useful marker for the detection of multivessel CAD, 13 and an independent inverse relationship between quantitative myocardial perfusion and PET ventricular synchrony has been suggested. 14 Notably, the link between quantitative PET myocardial perfusion and ventricular mechanical synchrony when considering the potential confounding influence of fixed perfusion defects, indicators of previous myocardial infarction [MI] and scarring, has not been investigated in HF patients. Hence, the present study aimed to explore the relationship between quantitative PET myocardial perfusion and peak stress ventricular mechanical synchrony when accounting for the presence and extent of pre-existing fixed perfusion defects in patients with chronic HF.…”

Phase analysis of gated PET in the evaluation of mechanical ventricular synchrony: A narrative overview

“…A large number of published reports on mechanical ventricular synchrony evaluated with PET have utilized 18 F-FDG and 82 Rb as viability and perfusion radiotracers, respectively. In fact, only one study has evaluated correlates and determinants of synchrony measurements from 13 N-ammonia PET perfusion data,19 while no study has utilized 15 O-water for such evaluation.…”

A perfect tool for comprehensive evaluation of myocardial perfusion and function: Stress PET imaging

“…The authors further proposed that characterizing the fixed perfusion defects with SRS might be a more convenient approach for treatment in order to improve ventricular mechanical dyssynchrony. Interestingly, the same group had a similar study in which the enrolled patients were also referred for N-13 ammonia PET due to suspected myocardial ischemia but not limited to chronic heart failure; 9 however, sMBF is better than MPR, SSS, and SRS in predicting peak-stress ventricular synchrony independently from other relevant cardiovascular risk factors and clinical covariates. The different results between the authors' two studies might be caused by the more complicated mechanism of ventricular synchrony in patients with chronic heart failure and the further study is needed to answer this question.…”