Circulatory Arrest

Introduction

Despite the advent of novel endovascular options and the advancement of microsurgical techniques and instruments, a small subset of intracranial aneurysms present a challenge to the neurovascular practitioner. Intracranial aneurysms of large or giant dimensions may be difficult to treat with conventional techniques, as are aneurysms located at the basilar tip, posterior circulation, and other anatomical areas that hinder adequate anatomical exposure for surgical intervention. Furthermore, aneurysms with significant thrombosis or feeder arteries may be unsuitable for conventional treatment without exposing the patient to significant perioperative morbidity and mortality. While alternative surgical treatments such as extracranial to intracranial bypass with indirect clipping, temporary clips, and endovascular stenting has further reduced the number of patients not suitable for conventional therapy, there continues to be a need for circulatory arrest during intracranial aneurysm surgery to facilitate definitive treatment of these aneurysms.

Circulatory arrest offers the advantage of decreasing aneurysm turgidity for clip placement, minimizing the risk of aneurysm rupture, and allowing delicate dissection needed for permanent clip application. In this chapter, two techniques of circulatory arrest currently being utilized in the treatment of intracranial aneurysms will be presented.

Deep Hypothermic Circulatory Arrest

The use of deep hypothermic cardiac arrest (DHCA) in the surgical treatment of intracranial aneurysm was initially reported over 50 years ago. However, due to the complexity of DHCA and cardiopulmonary bypass (CPB), the popularity of this technique waned in favor of advancing microsurgical clipping and endovascular strategies. Renewed interest in DHCA appeared around the turn of the century as improvements in CPB machines and anesthesia techniques allowed the re-exploration of DHCA as an option for surgical management of large or unfavorably located aneurysms. Despite these advances, DHCA is still associated with high morbidity and mortality and currently limited to highly selective patient populations at quaternary hospital centers with specially trained neurosurgeons.