Reversible reduction of cardiac sympathetic innervation after coronary artery bypass graft surgery: An observational study using serial iodine 123–labeled meta-iodobenzyl-guanidine (MIBG) imaging

Abstract

Objectives: Various types of surgical and interventional procedures have been reported to cause cardiac sympathetic denervation. We aimed at evaluating the effects of coronary artery bypass grafting (CABG) in cardiac sympathetic innervation through meta-iodobenzyl-guanidine (MIBG) imaging. Methods: MIBG imaging was performed in 21 patients with coronary artery disease (CAD) 1 day before and 1 week and 6 months after CABG with concomitant measurements of corrected QT interval. In each study we evaluated MIBG defect score in a 16-segment left ventricular model, MIBG-defect size (percent) from generated polar maps, and heart/mediastinum ratio. Results: Mean MIBG defect score and size were increased (32 AE 9.5 vs 24 AE 5, P<.0001, and 49.5% AE 20.4% vs 37% AE 8.7%, P ¼ .004, respectively) and mean heart/mediastinum ratio was reduced (1.5 AE 0.4 vs 1.9 AE 0.3, P<.0001) at 1 week after CABG. At 6 months these indices had no significant differences compared with their pre-CABG values. Mean corrected QT interval demonstrated no significant changes. Increase in MIBG score in the second imaging was associated with adverse events related to arrhythmia and myocardial dysfunction during the 6-month follow-up period in a binary logistic regression model. Conclusions: CABG is associated with clinically important but reversible reduction in cardiac sympathetic nerve function, with periprocedural effects (cardioplegia, hypothermia, ischemia, direct nerve injury) being possible mechanisms for this finding.

ESC Joint Working Groups on Cardiovascular Surgery and the Cellular Biology of the Heart Position Paper: Peri-operative myocardial injury and infarction in patients undergoing coronary artery bypass graft surgery

“…Other radionuclide imaging approaches are currently under intense investigation, and will likely be tested in the next few years. 68 …”

The NADPH oxidase inhibitor apocynin improves cardiac sympathetic nerve terminal innervation and function in heart failure

“…Cardiac sympathetic denervation is clinically relevant. Alterations in cardiac sympathetic nerve terminal function are implicated in myocardial dysfunction (Katsikis, Ekonomopoulos, Papaioannou, Kouzoumi, & Koutelou, 2012).…”