Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3742_Библиотеки_им_академика_М_И_Перельмана

be difficult to identify the true and false lumen even on inspection. Given that multiple fenes­trations exist even if the true lumen is definitively assessed in the groin, that may not ensure that the guide wire will remain in the true lumen as it is advanced cephalad. Therefore, careful evaluation of preoperative CTA, intravascular ultrasound, and angiography via the sheath at the level of each branch vessel is necessary.

As thoracic endografts are subject to a more forceful aortic impulse than infrarenal endografts, over a long period this may result in device migration (>10 mm) or component separation. The incidence of migration has been reported at 7% in a series of 123 patients over a median follow­up of 3 years and associated incidence of type I or type III endoleak of 44%.

Risk factors for graft migration include:

A. Neck angulation >60 degrees B. Neck length <15 mm C. Inadequate overlap between components (<5 cm) D. Extreme tortuosity in the thoracic segment

Verzini, F., Isernia, G., Simonte, G., et al. (2015). Results of aberrant right subclavian artery aneurysm

For an isolated descending thoracic artery aneurysm, the patient is placed in a right lateral decubi­tus position with the left thorax upwards. At the discretion of the surgeon, a lumbar spinal drain is used to prevent spinal cord ischemia (SCI). A left posterolateral thoracotomy is performed, and the left chest is entered via the fourth intercostal space if the transverse aortic arch is to be intervened upon or via the eighth intercostal space for the distal descending thoracic aortic aneurysm tho­racic. The left femoral vessels are exposed using a transverse inguinal incision for cannulation in readiness for cardiopulmonary bypass (CPB). The descending thoracic aorta is mobilized for resec­tion. When a large aneurysm that contains debris is mobilized, atheromatous emboli can travel retrograde to the cranial vessels; therefore, the aorta should not be touched until an appropriate time of circulatory arrest. If there is insufficient room to cross-clamp the aorta proximally, cardio­pulmonary bypass with deep hypothermic circulatory arrest (DHCA) is usually recommended. Otherwise, left heart bypass or femoral artery–femoral vein bypass (partial CPB) techniques can be used. This does not necessitate circulatory arrest. When CPB is performed, 2–3 units of autologous blood are withdrawn for later reinfusion. After heparinization, a venous cannula is inserted under transesophageal echography (TEE) guidance into the right atrium using a Seldinger technique via the left common femoral vein. The left common femoral artery is isolated, and an 8-mm Dacron graft is sewn in an end-to-side manner via a transverse arteriotomy for arterial return. W hen the long segments of the aorta are to be replaced, the distal clamp is initially set at approximately T5 to maintain lower intercostal artery perfusion; the distal clamp is then repositioned at the distal tho­racic aorta when constructing the distal anastomosis. After proximal and distal anastomoses are constructed, the intercostal arteries are reattached, if felt necessary, by isolating a segment of the graft. Alternatively, the intercostal artery patch reimplantation can occur before the distal anasto­mosis to reduce the SCI time. The clamps are removed, and the CPB is stopped when the patient is normothermic. The left femoral arter y is primarily repaired. Hemostasis is assured with protamine sulfate and autologous blood. The native aneurysm is closed over the graft to separate from adja­cent viscera, chest tubes are placed, and thoracotomy and groin wounds are closed.

The most common complication following open descending thoracic aortic aneur ysm repair is post­operative respiratory failure. Risk factors for postoperative respiratory failure include active cigarette smoking, COPD, coronar y artery disease, chronic kidney disease, or bleeding complications. Early ambulation and incentive spirometr y in addition to ensuring tobacco cessation prior to surgery are important strategies to decrease the incidence of respirator y failure. Intraoperative intercostal nerve cryoablation reduces narcotic use and postoperative pain, thus leading to deep inspiration and expi­ration following thoracotomy and help reduce the incidence of respiratory failure.