Endovascular thoracic aortic repair





An 83-year-old man with a past medical history significant for coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, hypertension, and previous abdominal aortic aneurysm repair presented with a 7-cm descending thoracic aortic aneurysm. The descending aortic aneurysm began 5 cm distal to the left subclavian artery and extended for 30 cm. Because of the patient’s concurrent medical conditions, an endovascular repair was planned. Several self-expanding endograft devices were used.


Anesthesia and surgery progressed without incident. In the postanesthesia care unit, the patient became febrile and mildly hypotensive and developed oozing at the surgical sites.




1


What is the difference between conventional descending aortic reconstruction and endovascular aortic repair?


Endovascular aortic repair (EAR) is an alternative to conventional surgical repair of aortic pathology. Endovascular grafts are less invasive than conventional arterial reconstructions. Endovascular grafts are inserted through small openings from remote arterial access sites and do not require large abdominal incisions. This technique obviates the need for extensive and prolonged aortic occlusion, decreases blood loss, and avoids significant fluid shifts that occur with visceral manipulation, reducing the risk of significant hemodynamic changes perioperatively.


Because long-term outcome studies of EAR are lacking, younger patients with minimal or no medical comorbidities are frequently treated with open repairs because of their established track record and low complication rate. Patients with severe medical comorbidities may be better candidates for endovascular reconstruction.




2


List the anatomic requirements and restrictions for endovascular aortic repair.


Not all patients with aortic pathology have suitable anatomy for endovascular repair. For EAR to be successful, the device must form a tight seal between graft and native artery. The proximal neck (i.e., proximal “landing zone”) must be at least 15 mm in length, and the aneurysm neck diameter should be no larger than the largest endograft available. Similarly, the distal attachment site must be nonaneurysmal and of sufficient length to accommodate a graft. No important aortic side branches, such as an accessory renal artery or inferior mesenteric artery, can be present in the aortic segment that is to be excluded. As a practical matter, excessive aneurysm neck tortuosity, severe calcification, aneurysmal necks >26 mm in diameter, and aneurysmal necks <10–15 mm in length may be relative contraindications for EAR. Finally, there must be at least one large, straight iliac artery that can accommodate passage (i.e., act as a conduit) of the endograft delivery system.




3


What are the recognized surgical complications of endovascular aortic aneurysm repair?


Although EAR is a less invasive technique compared with open repair, it is nonetheless associated with significant perioperative complications. Iliac or aortic anatomy and pathology may preclude insertion of endovascular sheaths (delivery systems). The possibility always exists of iatrogenic arterial rupture, which may necessitate emergent resuscitation and immediate conversion to an open procedure, increasing the morbidity and mortality associated with the repair.


Injury to the aorta and end-organs may occur with guidewire insertion and device manipulation via either embolization or obstruction. Distal embolization of aortic material to the bowel, lower extremities, or other organs is common. Although the endovascular device may obstruct hypogastric artery flow, complications have not been reported. Retrograde thromboembolism as a result of graft manipulation, injection of large volumes of contrast material, vigorous flushing, or the passage of guidewires through a diseased aortic arch may result in cerebral injury. Inadvertent guidewire placement into the heart has occurred with injury to the aortic valve or pericardial tamponade with resultant hemodynamic collapse.


Segmental or total renal injury may occur as a complication of EAR. Graft migration, renal artery dissection, and improper placement of the proximal portion of the endovascular device can occlude the renal arteries. Renal artery occlusion may lead to renal insufficiency and the possibility of further procedures to correct the problem. A significant amount of contrast material is used during these procedures to define aortic anatomy, providing another possible mechanism for renal injury ( Box 35-1 ).



BOX 35-1

Recognized Surgical Complications of Endovascular Aortic Repair




  • •

    Insertion of endovascular delivery system precluded



    • •

      Iliac artery anatomy or pathology


    • •

      Aortic anatomy or pathology



  • •

    Artery rupture with hypotension


  • •

    Embolization of aortic material



    • •

      Bowel


    • •

      Lower extremities


    • •

      Brain


    • •

      Other organs



  • •

    Guidewire trauma



    • •

      Aortic valve


    • •

      Myocardial perforation with cardiac tamponade



  • •

    Graft malposition



    • •

      Renal artery occlusion leading to renal impairment


    • •

      Occlusion of intercostal or anterior spinal cord artery leading to paralysis



  • •

    Postimplantation syndrome


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Jul 14, 2019 | Posted by in ANESTHESIA | Comments Off on Endovascular thoracic aortic repair

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