Improving Myocardial Perfusion by Percutaneous Coronary Intervention Reduces Central Sympathetic Activity in Stable Angina

BACKGROUND: By stimulating sympathetic afferents, repetitive myocardial ischemia induces a state of increased sympathetic tone. HYPOTHESIS: Removing the ischemic trigger by revascularization using percutaneous coronary intervention (PCI) might thus reduce central sympathetic activity in symptomatically stable angina patients. METHODS: A total of 20 patients with stable angina > or = New York Heart Association (NYHA) class II with persistent symptoms despite maximal pharmacological therapy and a clinical indication for PCI, were included in our study. Sympathetic nervous system activity was measured before and 1 month after PCI by a combination of techniques: direct muscle sympathetic nerve activity (MSNA), neurochemical (plasma catecholamine levels), and heart rate variability (HRV). RESULTS: All patients completed the study. After PCI there was a significant reduction in MSNA (pre-PCI 72 +/- 4 to post-PCI 53 +/- 4 burst/100 beats, P < .05) and low frequency/high frequency (LF/HF) ratio (3.7 +/- 0.6 vs 2.4 +/- 0.4, P < .05) consistent with a decline in sympathetic activity. Plasma norepinephrine levels were reduced after PCI, but this difference did not reach statistical significance (1.84 +/- 0.17 vs 1.73 +/- 0.13 nmol/L, P = not significant). CONCLUSION: Coronary revascularization by PCI reduces sympathetic activity in patients with established myocardial ischemia.