Rapid Ventricular Pacing in Neurovascular Surgery: Effectiveness and safety
16 december 2019
Antwerp University Hospital (UZA) - Auditorium Kinsbergen (route 12) - Wilrijkstraat 10 - 2650 EDEGEM (route: UAntwerpen, Campus Drie Eiken
Prof T. Menovsky & Prof M. Vercauteren
PhD defence Vera Saldien - Faculty of Medicine and Health Sciences
The prevalence in the adult population of unruptured aneurysms varies between 3% and 5%. The most feared complication of a cerebral aneurysm is rupture, leading to a subarachnoid hemorrhage (SAH). The incidence of a SAH, caused by the rupture of an aneurysm is less than 0,02 % a year.
The therapy of a cerebral aneurysm is performed on a selective, case-by-case basis. The three main options are observation, endovascular coiling and microsurgical clipping.
Several techniques have been proposed to decrease the intra-aneurysmal pressure, to prevent its premature rupture or to reduce the intraoperative bleeding in case of a rupture during clipping. The most widely used technique for facilitation of the dissection and a better visualisation of the aneurysm, branches and perforators is the temporary clipping of the feeding arteries.
Our research project indicates that RVP is a technique well suited in those circumstances where short, repetitive flow arrests are adequate to allow the neurosurgeon to manipulate the aneurysm.
Rapid ventricular pacing (RVP) enforces ventricular tachycardia, ventricular filling is compromised because of the high rate and the absence of atrioventricular synchrony, leading to decreased blood pressure without causing cardiac arrest and vasodilatation.
We demonstrated that RVP is an effective blood pressure lowering technique operating as an on-off mechanism. Blood pressure and CBF dropped with 50% after RVP initiation, remained at that level during the pacing and rebounded to pre-pacing values immediately after RVP cessation.
We analysed the effect of RVP on the heart. Our study results indicated that troponin levels increased slightly following RVP and normalised to pre-operative levels 24h after surgery.
The intra- and post operatively impact of RVP on the brain was evaluated. We used PbtO2 and rScO2 intra-operatively as measures of cerebral oxygenation. Whereas blood pressure reacts in an on-off mode to RVP, the impact on cerebral oxygenation is delayed and extends beyond the pacing period.
Postoperatively, we compared pre- and postoperative MRI to assess the impact of RVP on the brain. No new areas of restricted diffusion were observed in the contralateral hemisphere or posterior fossa.
The safe application of RVP requires a concerted effort of the neuro- surgeon and anesthesiologist.
Following the conclusion of this research project, the use of RVP in neurosurgical surgery has been reinstated and has been included in the standard intra- operative management of neurovascular clipping in our centre.