The Role of the Sympathetic Nervous System in the Pathomechanism and the Therapy of Hypertension

• Main Author: Légrády, Péter
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2013
• Subjects: Atherosclerosis; Blood pressure; Cardiac arrhythmia; Cardiovascular disease; Compliance; Drug dosages; Health care; Health sciences; Heart attacks; Heart rate; Hypertension; Lifestyles; Medical imaging; Medical screening; Medicine; Metabolism; Nervous system; Neurosciences; Pathogenesis; Pathology; Pharmaceutical sciences; Plasma; Poisons; Prescription drugs; Primary care; Public health; Respiration; Risk factors; Sodium; Software; Tumors
• ISBN: 9798381052251

In the first study reported in this thesis we hypothesized that the complications generally attributed to DM only may also appear in NDHT. In our work both CAN and PSN could be observed together in NDHT and their severity did not differ significantly from that in DHT. It may further support the view that vascular factors may play an essential role in the development of neuropathy. The duration of the HT rather than the BP values themselves might be an important risk factor for the development of autonomic and peripheral sensory neural dysfunctions. Our results provide further support for parasympathetic dysfunction enhancing SNA in HT and DM. The BRS decreased in both lying and standing positions in diabetic and nondiabetic HT groups, but it was lowest in the diabetic group, supporting the idea that DM and HT together may multiply the CV risk. Our results may suggest that poorly healing ulcers of the lower extremities, due to microvascular complications and often leading to amputation based on PSN, threaten not only diabetic patients but also NDHT. These observations might be essential for the development of risk reduction strategies among NDHT to avoid or postpone the development of neuropathy.In the second work of this thesis we collected retrospective data about invasive treatment methods of RHT, focusing on NVD of the brain stem. In the cases of severe primary RHT, without any possible so-called conventional secondary causes, not responding to multiple combinations of therapy, NVPC of the brain stem should be considered and MRA performed. If NVPC is confirmed by MRA, successful neurosurgical NVD of the brain stem on the left side can guarantee a BP reduction with less or same need for antihypertensive medication. From our results NVPCs on the left side of the brain stem may relate to HT, but the type of the NVPC does not correlate with the BP values. Therefore, perhaps, neither the location nor the number of NVPCs on the left side affects the degree of the SNA. From this point of view the fact of NVPC on the left side is the most important not its type. A continuous pulsatile stimulation of the RVLM on the left side may lead to a tonic increase in SNA and HT, but it cannot explain all the refractory HTs. A new question arises here: if NVD may affect the BP and the SNA, is it really a case of a primary HT or is it a case of an unconventional secondary form? More data are needed to decide this. Further, our results – MRA findings compared to intraoperative observations - may confirm that MRA slice thickness 1 mm is necessary for successful identification of an NVPC.Before any invasive treatment of RHT the pseudoresistant HT, the "white-coat effect", the conventional secondary causes and other patient- and/or therapy-related causes should be excluded. After confirming the primary RHT it is important to optimize the medical antihypertensive treatment. Is RDN the appropriate next step? If the office BP is sustained >160/ mmHg with eGFR >45 ml/min/1.73 m2 and the anatomy of renal artery is suitable then the answer is "yes". Compared to NVD, the RDN is an easier invasive technique with fewer possible side effects and a shorter procedure time.