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Acute Stanford type A aortic dissection is typically presented as antegrade dissection from a primary intimal tear in the proximal ascending aorta extending to the arch and the downstream distal aorta. However, it may also develop in a retrograde fashion with an intimal tear located in descending aorta causing retrograde extension of aortic dissection into ascending aorta, namely, retrograde type A aortic dissection (RTAAD). Though open surgery remains the golden standard to treat type A dissection, as to RTAAD, the distal location of its primary entry tear in descending aorta warrants more extensive aortic repair with higher surgical risks of mortality or morbidity through a median sternotomy. Conversely, confining the surgical extent to the proximal aorta leaves the risks of complications related to the residual tear in the distal aorta untreated. More recently, thoracic endovascular aortic repair (TEVAR) is attempted for the treatment of RTAAD with favorable short-term and long-term prognosis. To the best of our knowledge, this was the largest serial study to apply TEVAR in the treatment of RTAAD.
From September 2013 to December 2016, 43 patients were recruited in our study. Inclusion criteria were as follows: (1) acute RTAAD demonstrated by computed tomography angiography (CTA) without any entry tear in ascending aorta or proximal aortic arch; (2) no signs of cardiac tamponade or severe aortic regurgitation or sever hemodynamic disorder; (3) no signs of ischemia of coronary artery or arch branches; (4) no previous history of cardiac or aortic surgery; (5) rule out the possibility of Marfan syndrome or other connective tissue disorders.
Coated endovascular stent was implanted through femoral artery and all procedures were technically successful. Fenestration technique was applied in six patients. Left subclavian artery was intentionally occluded in 16 patients, reconstructed through hybrid procedure in two, and remained uninfluenced or partial occluded in the rest nineteen patients. Intraoperative angiography showed complete coverage of the primary entry tear without any retrograde fashion of blood flow in ascending aorta.
No stroke, or paraplegia, or new intimal tear in the proximal ascending aorta, or endoleak, or stent immigration was observed during perioperative period. Postoperative morbidity rate was 7% (three cases), including mental dysfunction in two cases, acute renal failure in one. These three cases recovered during hospitalization. There was one perioperative death (2%) due to multiple organ failure which was a result of severe ventilator associated pneumonia.
During follow-up period (12∼36 months), no aortic related event was reported. CTA showed TEVAR resulted in complete thrombosis of false lumen, reabsorption of false lumen thrombus, and enlargement of true lumen. Mean maximal area of false lumen in ascending aorta significantly decreased (941±214mm2 vs. 631±301 mm2, P<0.01) after TEVAR. At the distal edge of stent graft, mean whole area of descending aorta remained stable (739±198mm2 vs. 721±236 mm2, P>0.05) after TEVAR.
TEVAR is a safe and effective technique in highly selected patients for the treatment of RTAAD. It is minimally invasive and ensures speedy patient recovery; however, further large-scale follow-up studies are required to verify its long-term efficacy.