Surgical bypass procedures to facilitate endovascular repair of aortic arch pathology

Abstract

Thoracic aortic aneurysms and other thoracic aortic lesions may become life-threatening conditions if they remain untreated. Conventional open surgical reconstruction with placement of an interposition graft is regarded as a definitive form of treatment, but is associated with considerable operative morbidity and mortality. Thoracic aortic lesions involving the aortic arch require more complex surgical interventions necessitating cardiopulmonary bypass, and hypothermic circulatory arrest. Outcomes from this form of treatment have a reported early stroke and death rate of up to 25%. Thoracic endovascular aortic repair is a less invasive alternative for the treatment of many thoracic aortic lesions. The application of a thoracic endoprosthesis may be limited by the extent of involvement of the proximal thoracic aorta as coverage of arch vessel ostia may be necessary to obtain adequate proximal endograft fixation and aneurysm exclusion. In an effort to overcome proximal landing zone limitations imposed by arch vessel involvement, hybrid surgical-endovascular reconstructive and debranching bypass procedures have been performed to create a proximal landing zone of adequate length. Although these adjunctive techniques incorporate invasive surgical procedures, it is believed that minimizing the procedural invasiveness, by avoiding aortic cross-clamping and/or hypothermic circulatory arrest, morbidity and mortality outcomes can be improved especially in high-risk patients. Several surgical approaches and techniques have been described for various levels of aortic arch involvement with encouraging early and mid-term results, although the long-term durability of these hybrid surgical-endovascular procedures remains to be defined.