Bilateral sphenopalatine ganglion block reduces blood pressure in never treated patients with essential hypertension. A randomized controlled single-blinded study

Background Sympathetic fibers connect sphenopalatine ganglion (SPG) with the central nervous system. We aimed to study the effect of SPG block in blood pressure (BP) in never treated patients with stage I-II essential hypertension. Methods We performed bilateral SPG block with lidocaine 2% in 33 hypertensive patients (mean age 48 ± 12 years, 24 men) and a sham operation with water for injection in 11 patients who served as the control group (mean age 51 ± 12 years, 8 men). All patients have been subjected to 24 h ambulatory blood pressure monitoring prior and a month after the SBG block in order to estimate any differences in blood pressure parameters. We defined as responders to SBG block those patients with a 24 h SBP decrease ≥ 5 mm Hg. Results We found that 24 h and daytime DBP (p = 0.02) as well as daytime DBP load (p = 0.03) were decreased in the study group a month after SPG block. In addition, a significant response was noted in 12/33 responders (36%) regarding: a. SBP and DBP during overall 24 h and daytime (p < 0.001) and night-time periods, b. pre-awake and early morning SBP and c. SBP (daytime and night-time) and DBP (daytime) load. No differences regarding BP were found in the sham operation group. Conclusions SPG block is a promising, minimally invasive option of BP decrease in hypertensives, probably through SNS modulation. Additionally, due to its anesthetic effect, SPG block might act as a method of selection for those hypertensive patients with an activated SNS before any other invasive antihypertensive procedure.