Acute improvement of cardiac efficiency measured by 11C-acetate PET after cardiac resynchronization therapy and clinical outcome

Abstract

The purpose of this study was to examine the usefulness of (11)C-acetate positron emission tomography (PET) for assessing the efficacy of cardiac resynchronization therapy (CRT). Enrolled in this study were 20 patients with severe heart failure. All patients underwent 11C-acetate PET within 1 week after CRT. The oxygen consumption was measured by the monoexponential clearance rate of 11C-acetate (K(mono)) for both CRT-off and -on. Cardiac efficiency (CE) was determined using the concept of the work metabolic index (WMI). WMI was calculated as WMI = (stroke volume index) x (systolic blood pressure) x (heart rate)/K(mono). The patients were divided into two groups: 14 patients with improved CE (from 5.27 +/- 0.91 to 6.77 +/- 1.12) and 6 patients with deteriorated CE (from 5.35 +/- 0.92 to 4.86 +/- 0.84) by CRT-on. K(mono) decreased from 0.053 +/- 0.006 to 0.046 +/- 0.003 by CRT-on in the improved CE group (p = 0.028), but increased from 0.049 +/- 0.006 to 0.050 +/- 0.006 in the deteriorated-CE group (p = 0.036). Stroke volume index, systolic blood pressure, and heart rate did not change by CRT-on for either group. At the one-year follow-up, there were significantly higher rates of major cardiac adverse events in the deteriorated-CE group than in the improved-CE group (p = 0.032). Therefore, the improvement of CE, as assessed by 11C-acetate PET in the early period after CRT, is produced by the decrease in oxygen consumption in patients showing good responses to CRT. The decrease in oxygen consumption in the early period after CRT is thus a useful marker for predicting a good clinical outcome after CRT.

Cardiovascular imaging 2010 in the International Journal of Cardiovascular Imaging

“…Several PET studies in chronic CRT patients have shown that CRT improves oxygen metabolism and cardiac efficiency [28]. Kitaizumi et al now evaluated 20 patients very early (1 week) after CRT [29]. All patients underwent 11C-acetate PET and oxygen consumption was measured by the mono-exponential clearance rate of 11C-acetate (Kmono), while the biventricular pacemaker was off and then on.…”

Cardiac resynchronization therapy – beneficial alterations observed on molecular level – a review.

“…This contributes to reverse remodelling of the ventricles and supresses the asymmetry in hypertrophy resulting from LBBB [32] . Some studies have shown that CRT can even reduce the global energy cost of heart activity [25,33] . Importantly, heart failure and CRT induce subcellular changes affecting energy management.…”

Myocardial tissue and metabolism characterization in men with alcohol consumption by cardiovascular magnetic resonance and 11C-acetate PET/CT

“…The native T1 values of myocardial tissues vary with myocardial extracellular water (edema), focal or diffuse fibrosis, fat, iron, and amyloid proteins. Meanwhile, quantitative parameters measured from 11C-acetate positron emission tomography (PET) imaging, such as Kmono and K1, have been largely utilized to characterize myocardial metabolism in heart diseases [11][12][13][14]. Kmono is considered as a robust marker for evaluation of myocardial oxygen consumption (MVO 2 ), while K1 is correlated with myocardial blood flow (MBF) in absolute terms.…”