Successful treatment of atypical type A aortic dissection after heart transplantation.

We report a case of a 58-year-old female with Stanford type A aortic dissection sparring the donor aorta 2 years after heart transplantation. Lumbar spine magnetic resonance examination for low back pain discovered the aortic dissection which was confirmed by following computed tomography angiography. The patient received surgical treatment including total arc replacement and thoracic aortic endovascular repair and recovered well.

INTRODUCTION

Aortic dissection is a rare but fatal complication following orthotopic heart transplantation (HTx) that may occur in both early and late period [1]. Only few case reports have reported aortic dissection in HTx patients [2, 3]. In this case report, we described a rare case of type A aortic dissection sparring the donor aorta 2 years after HTx.

CASE REPORT

A female patient underwent HTx for end-stage dilated cardiomyopathy in 2018 at the age of 56. The patient was successfully discharged 3 weeks after HTx and received immunosuppression including tacrolimus, mycofenolate mofetil and corticosteroids. Candesartan and low-dose diuretics with oral potassium chloride were prescribed to control blood pressure. Insulin glargine and insulin mendon were regularly given for the treatment of type 2 diabetes. Since July 2020, the patient experienced low back pain without other severe symptoms compatible with aortic dissection including chest pain. Monthly examination of echocardiography revealed no abnormality of heart and aortic root. Several chest computed tomography scans performed before the onset of low back pain also showed no abnormality of the aorta. Two months later, she was referred to lumbar spine magnetic resonance examination. The intima-flap appearance within aorta on magnetic resonance axial localizer images (Fig. 1) was highly suggestive of aortic dissection. The patient was emergently transferred for computed tomography angiography. On computed tomography angiography images, the tear entered at aortic arc proximal to origin of right common carotid artery. The dissection extended through aortic arc, descending aorta to left iliac artery with spontaneous recanalization (Fig. 2). While the bilateral common carotid and subclavian arteries, superior and inferior mesenteric arteries, right renal artery were perfused from the true lumen, the coeliac trunk and left renal artery were perfused from the false lumen. Bilateral common carotid and subclavian arteries were found to originate from aortic arc individually. Besides, the aberrant right subclavian artery arose distal to the left subclavian and hooked back to reach the right side posterior to oesophagus.

Figure 1:

The abdominal aorta in axial localizer images showed the presence of double-lumen separated by linear low signal, indicating aortic dissection.

Figure 2:

The tear originated at lesser curve of aberrant right subclavian artery (D), the distal portion of ascending aorta was involved (C), but the aortic root was free of involvement (B). The dissection crossed the aortic arc and extended the whole descending aorta with spontaneous recanalization at terminal of left iliac artery (A, E).

The patient was immediately admitted to cardiac surgery department of our institute where she underwent heart transplantation. Upon admission, the patient showed hypertension (150/100 mmHg) and tachycardia (115 bpm). Uradil hydrochloride and esmolol hydrochloride were given for strict control of blood pressure and heart rate. Ten days later, she underwent total arc replacement using a 4-branched graft and concomitant retrograde thoracic endovascular aortic repair. Cardiopulmonary bypass was instituted after percutaneous cannulation of the right femoral vein. Intraoperatively, an entry was found at lesser curve of right common carotid artery, the intimal flap extended to involve upper portion of ascending aorta and ended at 3 cm above the aortic anastomosis. The aortic arch was transected under moderate hypothermic circulatory arrest. After the distal anastomosis with thoracic aorta, the ascending aorta was anastomosed to proximal end of the graft. Four arch vessels including the aberrant right subclavian artery were firstly transected and then reconstructed individually. A 30 × 200 mm covered stent was deployed with a minimum 2.0-cm landing zone on the aortic graft through right femoral access.

The postoperative recovery was complicated by pulmonary infection and pleural effusion. At present, the patient is doing well 3 months after surgical treatment.

DISCUSSION

Aortic dissection following HTx has been reported in several cases with type A dissection involving the donor aorta or type B dissection restricted to native aorta. As far as we know, we report the first case of chronic type A dissection following HTx sparring the donor aorta. It was believed to be the first report of successful treatment of type A aortic dissection in HTx patient combining the use of total arc replacement and thoracic endovascular aortic repair.

Aortic dissection in HTx patients has been attributed to technical mistakes in early phase after transplantation and degenerative processes in late period [4]. The type A dissection sparring donor aorta in our patient was more likely related to hypertension and immunosuppression. The condition of diabetes was also believed to be a risk factor [5]. Other than chest pain or dyspnoea reported previously [3], the complaint of our patients was low back pain. The atypical symptom may be caused by dilation of aorta, patency of main braches of aorta may help prevent severer symptoms. Echocardiography was helpful in detecting asymptomatic type A dissection involving donor aorta [1]. As aortic root was free of involvement in our patient, the dissection may be difficult to detect with echocardiography. There is a silver lining that the magnetic resonance examination for lumbar spine discovered the dissection and led to the confirmative computed tomography angiography scan.

The treatment of aortic dissection in HTx recipients follows the same principles applicable to general population. As the donor aorta and aortic valve were free of dissection, total arc replacement was adopted to repair the tear site and the false lumen was obliterated by thoracic endovascular aortic repair.

Conflict of interest: none declared.