Abstract

Endovascular treatment methods are often preferred in suitable patients with complicated acute type B aortic dissection due to the high mortality and morbidity associated with the open surgical procedure. Retrograde aortic dissection is a rare complication of endovascular procedures. Herein, we reported surgical treatment of a retrograde aortic dissection that developed after thoracic endovascular aortic repair in a 53-year-old male patient with a history of liver transplantation two years ago and taking immunosuppressive medication.

Retrograde aortic dissection (RAD) is a rare yet life-threatening complication that can occur following thoracic endovascular aortic repair (TEVAR). During TEVAR, the presence of acute aortic pathology, mismatch of stent graft, the weakness of the aortic wall and periprocedural aortic injury were shown to be important in the development of RAD.[1] Furthermore, Ma et al.[2] demonstrated that while the presence of a proximal bare stent does not elevate the risk for RAD, the use of an endovascular graft with a connecting bar and a length exceeding 165 mm significantly increases the risk of RAD. Herein, we presented the surgical management of RAD observed following TEVAR in a liver transplant patient who was undergoing treatment with steroids and everolimus.

Case Presentation

A 58-year-old male patient was admitted to the hospital with a new-onset progressively increasing severe back pain for the last 2 h. On admission, the vital signs were normal, except for the blood pressure (185/100 mmHg). The medical history of the patient was significant for liver transplantation (LT) two years ago, and the patient had been receiving everolimus and steroid therapy since the transplantation. The patient was also diagnosed with hypertension immediately after LT and had been taking enalapril. The laboratory work, which showed a serum creatine level of 0.80 mg/dL, was unremarkable. Contrast-enhanced thoracoabdominal computed tomography (CT) revealed Stanford type B acute aortic dissection, starting from the proximal descending aorta just distal to the left subclavian artery (LSA) ( Figure 1). Despite optimal pain management and blood pressure control, severe back pain persisted. Control thoracic CT revealed no new findings 24 h after admission. The sizing of the landing zone of TEVAR graft was judged by preoperative three-dimensional CT ( Figure 2a). The patient underwent TEVAR with an endovascular graft of 34 mm in proximal diameter (Medtronic Vaillant II, Santa Rosa, CA, USA) via the right femoral artery without graft oversizing and balloon dilatation 40 h after admission. The graft was released at the distal aortic arch just distal to the left common carotid artery (LCC) take-off (Ishimaru Zone 2), with overstenting of the LSA. A short-segment Dacron graft (Intergard; Getinge, Maquet Getinge Group, Antalya, Türkiye) 8 mm in diameter was interposed between the LCC and LSA. Completion angiography showed no abnormalities, and there was no evidence of a dissection flap. The patient was transferred to the intensive care unit and extubated 2 h after the procedure. Both intraoperatively and postoperatively, blood pressure was effectively managed with intravenous esmolol and nicardipine. The patient experienced severe chest pain immediately following extubation. The diagnosis of RAD was confirmed by thoracic CT. Written informed consent was obtained from the patient for the publication this case report.

Figure 1: Preoperative CT image showing Stanford type B acute aortic dissection. (a) axial view and (b) sagittal view, red arrow heads show the intramural hematoma starting from the descending aorta just distal to the LSA. CT: Computed tomography; LSA: Left subclavian artery.

Figure 2: (a) Preoperative three-dimensional CT imaging of the aortic segments for intraoperative planning. The diameter of the proximal landing area at the aortic arch just distal to the left carotid artery was almost 34 mm. (b) The sagittal view shows retrograde Stanford type A dissection originating from the base of the innominate artery and extending down to the sinotubular junction (red arrows). (c) Intraoperative view of the intimal reentry for RAD (black arrow), brachiocephalic artery (white arrow), and LCC (dashed arrow). (d) Intraoperative view of the completed repair of RAD. (e) Postoperative fluid collection around the ascending aortic graft (white arrow). CT: Computed tomography; RAD: Retrograde aortic dissection; LCC: Left common carotid artery.

The entry tear occurred at the contact zone between the stent struts and the orifice of the brachiocephalic artery ( Figure 2b). An emergent surgery involving median sternotomy and cardiopulmonary bypass was considered the most appropriate approach for the treatment of RAD. Under cardioplegia (del Nido) and deep hypothermia, the entry point was found to be at the contact point of the graft struts with the orifice of the brachiocephalic artery ( Figure 2c). The aortic arch and the ascending aorta were replaced (32-mm Intergard Dacron graft; Getinge, Maquet Getinge Group, Antalya, Türkiye), and the brachiocephalic artery (BCA) and LCC were implanted onto the graft separately using 12-mm and 8-mm Intergard Dacron grafts, respectively ( Figure 2d). The struts of the TEVAR graft were cut, and the distal part of the arch graft was anastomosed to the previously implanted TEVAR graft. In the early postoperative period, the patient underwent two revisions for bleeding on the first and second postoperative days without any surgical bleeding. The patient was extubated on the fifth postoperative day and transferred to the ward on the ninth postoperative day. On the 10th postoperative day, fever and sternal wound discharge were detected. Blood and wound discharge cultures revealed methicillin-resistant Staphylococcus epidermidis. Thoracic CT imaging revealed persistent fluid collection around the graft, dictating a possible early graft infection ( Figure 2e).

The patient underwent resternotomy for graft infection. A limited upper median laparotomy was also performed for preparation of the omental flap. A graft-preserving strategy was applied with drainage of mediastinal pyogenic material, antibiotic irrigation of the mediastinum, and support of the aortic grafts externally with an omental flap accompanied by systemic antibiotic therapy. For the purpose of antibiotic irrigation, a hemodialysis catheter was placed into the mediastinum during revision. For two weeks after the operation, the mediastinum was irrigated daily for a period of 16 h with 1,000 mL of 0.9% saline containing 1,000 mg vancomycin and 240 mg gentamicin via the dialysis catheter, as previously described.[3] The mediastinal drains were occluded during infusion. During the remaining 8 h, the drains were opened to remove the infusion fluid out of the body. The culture of the re-exploration material revealed the same microorganism. Systemic antibiotherapy was continued for five weeks postoperatively. The postoperative course was uneventful, and the patient was discharged on the 47th postoperative day. Labeled leukocyte scintigraphy confirmed the absence of graft infection two and a half years after surgery ( Figure 3a, b). The patient remained in good condition three years after the procedure.

Figure 3: Labeled leukocyte scintigraphy (a) sagittal view, (b) axial view showing the lack of graft infection two and a half years after surgery.

Discussion

In the present case, RAD after TEVAR and early infection of the prosthetic graft were successfully managed. The most important comorbidities for the development of both complications were hypertension, the history of LT, and the presence of an ongoing immunosuppressive therapy with steroids and everolimus, a mammalian target of rapamycin inhibitors (mTOR).

Retrograde aortic dissection is a rare but lethal complication of TEVAR and has an incidence of 2.5% and a mortality rate of 37.1%. The occurrence of RAD following TEVAR was reported to be higher in patients who underwent treatment for aortic dissection compared to thoracic aortic aneurysms, particularly when the proximal bare stent was preferred.[1] Despite no oversizing, our patient experienced RAD after TEVAR. The projecting struts of the stent were found to erode the intima around the orifice of the BCA at the operation. In a study by Dun et al.,[4] three main factors were identified in the development of RAD after TEVAR: (i) procedure related causes, (ii) device related causes, and (iii) the underlying aortic disease. As was stated in the literature, bending the stent within the aortic arch could put extra stress on the greater curvature, resulting in a new entry site for RAD. To minimize the risk of RAD, we neither oversized the graft nor performed aortic balloon dilation. In a study by Liu et al.,[5] it was shown that less that 5% oversizing was suitable to decrease the risk of RAD without increasing stent migration or type 1 endoleak rates in cases with acute type B dissection.

Recently, several authors have expressed concerns regarding the increased risk of arterial dissection and aneurysm development associated with antiangiogenic cancer therapies.[6] This includes mTOR inhibitors such as everolimus, multiprotein kinase inhibitors, and vascular endothelial growth factor inhibitors.[6]

Another important aspect to consider in this case is the selection of a graft-preserving strategy for treating aortic graft infections. While replacing infected synthetic aortic grafts with biological conduits has traditionally been the gold standard, in situ graft-sparing surgical techniques utilizing an omental flap have proven to be a safe and effective treatment option for patients with aortic graft infections. The primary rationale for the graft-preserving strategy is that it poses a lower risk of reoperation compared to graft replacement, provided that the preservation is performed within the first few months following the initial surgery.[3]

In conclusion, retrograde aortic dissection is a challenging complication that can occur after TEVAR. Patients with a history of ongoing immunosuppressive therapy, such as mammalian target of rapamycin inhibitors, may be at an increased risk for developing either primary aortic dissection or retrograde aortic dissection following TEVAR. Additionally, in cases of thoracic aortic graft infection, graft preservation should be considered an essential option for cardiac surgeons, particularly for patients with significant comorbidities.

Data Sharing Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Author Contributions: Idea/concept, critical review: K.A.; Design, literature review, writing the article: K.A., E.Ç.; Control/ supervision: K.A., S.A.; Data collection and/or processing, analysis and/or interpretation, materials: K.A., F.Ö.; References and fundings: S.A.

Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding: The authors received no financial support for the research and/or authorship of this article.

References

1) Zhang S, Chen Y, Lu Q. Retrograde type A aortic dissection complicating endovascular therapy of type B aortic dissection and descending thoracic aneurysm disease. Curr Opin Cardiol 2018;33:581-6. doi: 10.1097/HCO.0000000000000567.

2) Ma T, Dong ZH, Fu WG, Guo DQ, Xu X, Chen B, et al. Incidence and risk factors for retrograde type A dissection and stent graft-induced new entry after thoracic endovascular aortic repair. J Vasc Surg 2018;67:1026-33.e2. doi: 10.1016/j. jvs.2017.08.070.

3) Umminger J, Krueger H, Beckmann E, Kaufeld T, Fleissner F, Haverich A, et al. Management of early graft infections in the ascending aorta and aortic arch: A comparison between graft replacement and graft preservation techniques. Eur J Cardiothorac Surg 2016;50:660-7. doi: 10.1093/ejcts/ ezw150.

4) Dun Y, Shi Y, Guo H, Liu Y, Zhang B, Sun X, et al. The surgical management of retrograde type A aortic dissection after thoracic endovascular aortic repair. Interact Cardiovasc Thorac Surg 2020;30:732-8. doi: 10.1093/icvts/ivz326.

5) Liu L, Zhang S, Lu Q, Jing Z, Zhang S, Xu B. Impact of oversizing on the risk of retrograde dissection after TEVAR for acute and chronic type B dissection. J Endovasc Ther 2016;23:620-5. doi: 10.1177/1526602816647939.

6) Guyon J, Gouverneur A, Maumus-Robert S, Bérard X, Pariente A, Bikfalvi A, et al. Association between antiangiogenic drugs used for cancer treatment and artery dissections or aneurysms. JAMA Oncol 2021;7:775-8. doi: 10.1001/jamaoncol.2021.0210.