Bilateral sphenopalatine ganglion block reduces blood pressure in never treated patients with essential hypertension. A randomized controlled single-blinded study☆
Introduction
Arterial hypertension is associated with increased cardiovascular (CV) risk. While highly effective medical treatments exist, a substantial proportion of hypertensive patients remains inadequately controlled. The high prevalence and the subsequent complications of arterial hypertension along with difficulties in treatment and the limitations of pharmacological options led to the development of interventional approaches [1]. Sympathetic nervous system (SNS) acts as one of the main pathophysiological mechanisms which lead to arterial hypertension onset as well as to its maintenance [1], [2]. SNS blockage was a therapeutic target in hypertension disease in the past through surgical sympathectomy, nowadays we use beta blockers while in the near future invasive techniques like renal denervation are expected to be implemented in selected cases [3]. The minimal invasive procedure of SNS modulation through sphenopalatine ganglion (SPG) block follows the same track of therapeutic choices regarding arterial hypertension.
SPG block by topical anesthesia is currently indicated in the management of medically resistant cluster headaches, migraine, other trigeminal autonomic cephalalgias, postdural puncture headache as well as intractable orofacial pain syndromes [4], [5], [6], [7]. SPG is located in the cranial section of the autonomous nervous system; it is connected with the brain stem and the central nervous system (CNS) and bears unique characteristics favorable for the treatment of many painful syndromes involving the face and head [8], [9].
In a previous study, we hypothesized that SPG block through sympathetic nerves anesthesia might have resulted in blood pressure (BP) decrease. Indeed, that first study showed impressive results a month after the procedure in newly diagnosed and never treated hypertensive patients [10]. Blood pressure parameters were decreased in 24 h ambulatory blood pressure measurements (ABPM), especially in the group called responders (patients with 24 h average systolic BP decrease ≥ 5 mm Hg). However, that study was smaller and it did not include a control group.
The purpose of the present study is to re-examine the role of SPG block technique in BP parameters using ABPM in recently diagnosed and never treated middle-aged patients with mild to moderate essential hypertension compared to a control group of hypertensive patients in whom a sham operation of SPG block was applied.
Section snippets
Study population
We studied 44 Caucasian hypertensive patients visiting our outpatient clinic with recently diagnosed and never-treated stage I–II essential hypertension according to the 2013 guidelines of the European Society of Hypertension [1]. All patients were subjected to the following examinations within 2 weeks: 1) Three (3) office BP measurements in each one of the 3 subsequent visits in the hypertension outpatient clinic; 2) blood and urine sampling for routine blood chemistry (lipid profile included)
Statistical analysis
Unpaired and Paired Student t-test were used in order to compare numeric differences between the study group, the responders and the control group at baseline evaluation and any differences regarding BP parameters in each group separately before and after the SPG infiltration. All variables are expressed as mean ± standard deviation. Mann-Whitney test was used to compare categorical variables between groups. The level of statistical significance was determined as two-sided p < 0.05. Statistical
Results
The demographic, clinical characteristics and laboratory findings of the study group (n = 33, mean age 48 ± 12 years, 24 men), the responders (n = 12, mean age 47 ± 9 years, 8 men) and the control group (n = 11, mean age 51 ± 12 years, 8 men) are listed in Table 1. No abnormal findings were noticed in chest X-ray, electrocardiogram and left ventricular systolic function after echocardiograph. All patients were classified as NYHA class I without symptoms of diastolic dysfunction. No differences were found
Discussion
Decades ago, non-randomized studies showed that surgical sympathectomy was an effective treatment for some patients with uncontrolled hypertension, but profound postural hypotension along with increased morbidity and mortality rates occurred after the procedure, therefore it was abandoned [13]. In our days, the first successful results from renal denervation (RDN) studies shifted interest back to the old perception of sympathetic nervous system (SNS) over activation as a pathophysiological
Study limitations
Our study has a number of limitations which should be recognized. The number of patients overall and in each study group (study group, responders and control group) is low. The high prevalence of arterial hypertension in the population requires a greater number of patients in order to generalize the results of the study in untreated hypertensives, treated hypertensives on different medications or patients with severe hypertension due to activated SNS (i.e. chronic kidney disease population) [50]
Conclusions
Our results indicate that SPG block might be a promising, non invasive, safe, painless and easy to perform therapeutic option of arterial hypertension without any subsequent complications. It resembles to RDN as to the need of a bilateral application and the unknown immediate effect since no drop in blood pressure is seen just after the procedure. However, as SPG block just causes an anesthetic effect instead of destroying the nerve fibers, a lot of questions emerge regarding the long term
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The authors report no relationships that could be construed as a conflict of interest.