Sympathetic Hyperactivity and Aortic Sympathetic Nerve Sprouting in Patients with Thoracic Aortic Dissection

Background To determine the yet unknown relation between thoracic aortic dissection (TAD) and sympathetic nervous system activity. Methods Variables such as electrocardiography, blood pressure, respiratory activity, postganglionic muscle sympathetic nerve activity （MSNA）, plasma norepinephrine, tyrosine hydroxylase–positive nerve fiber density, and growth-associated protein 43–positive nerve fiber density were detected and statistically analyzed. Results TAD Patients showed a significant lower R-R interval variance and higher blood pressure, heart rate, respiratory rate, MSNA, plasma norepinephrine (reflecting elevated sympathetic nervous system [SNS] activity), higher tyrosine hydroxylase, growth-associated protein 43–positive nerve fiber density (reflecting sympathetic sprouting and innervation) than those of the control group. Conclusions In TAD patients, both overall and regional aortic SNS activities are elevated.