Treatment of coral reef aorta with open surgical endarterectomy – case report of a unique clinical entity

Overview

Introduction: Coral reef aorta (CRA) is a rare clinical entity characterised by hard, protruding calcifications in the juxta and supra-renal aorta, which cause haemodynamically significant stenosis of the aorta and its branches. We are presenting a case report of a 65-year-old female patient with bilateral 30-meter claudication on both lower extremities and a haemodynamically significant stenosis of the left renal artery.

Case report: The patient underwent computed tomography angiography (CTAG) of the abdominal aorta and lower extremities. CTAG revealed severe abdominal aortic wall calcification with circular atherosclerotic calcification in the area of the renal arteries branch off, causing haemodynamically significant stenosis of the aorta and the left renal artery. The patient was scheduled for an elective open surgery. The left retroperitoneal approach dissects the abdominal aorta, including both renal arteries. ­Cross-clamps were placed on both renal arteries, the subrenal aorta and the suprarenal aorta, just below the superior mesenteric artery. Circular aortic calcifications protruded through the aortotomy, and aortal endarterectomy was performed. The calcific plaques extend­ing to the left renal artery were dissected similarly. Identically, an endarterectomy of both common iliac arteries orifice was performed.

Result: The patient was discharged on the 8^th postoperative day with excellent renal parameters, normal left kidney perfusion, and without limiting claudications on both lower extremities. Currently, we have a 12-month follow-up with the patient.

Conclusion: CRA is a rare clinical entity. The optimal treatment has yet to be established. Up-to-date, the gold standard treatment for CRA is surgical endarterectomy.

Keywords:

Aorta – Atherosclerosis – endarterectomy – renal artery

Introduction

Atherosclerotic disease of the aorta mainly affects its distal parts, predominantly aortal bifurcation and branch ostia [1]. Coral reef aorta (CRA) is a rare clinical entity characterised by hard protruding calcifications in the juxta and the supra-renal aorta, causing haemodynamically significant stenosis of the aorta and its branches with prevalence around 0.6–1.8% [2,3]. In contrast to the typical appearance of the atherosclerosis of the great vessel, CRA calcifications grow irregularly into the lumen, resembling the shape of a coral reef [4]. CRA can cause lower limb malperfussion, renovascular hypertension, or visceral ischemia [5]. The treatment of CRA is complex as surgical treatment carries high postoperative complications and mortality. Endovascular treatment of highly calcified aorta carries a high risk of dissection or perforation [6].

 

Case report

A 65-year-old female patient was referred to our centre for bilateral short 30-meter claudication on both lower extremities. The patient‘s medical history showed arterial hypertension (WHO class II), hypothyreosis, and tricuspid regurgitation on conservative treatment. The patient‘s medication was a 100 mg daily dose of aspirin. The patient underwent computed tomography angiography (CTAG) of the abdominal aorta and lower extremities. CTAG revealed severe abdominal aortic wall calcification with circular athero­sclerotic calcification in the area of the renal arteries branch off, causing haemodynamically significant stenosis of the aorta and the left renal artery (Fig. 1). Based on the CTAG findings, endovascular treatments were ruled out for high risk of failure and complications. The patient was scheduled for an elective open aortic endarterectomy, including the left renal artery.

The procedure was performed under full anaesthesia in a supine position. Through a left pararectal incision, a retroperitoneal approach was used to dissect the abdominal aorta, including both renal arteries (Fig. 2). After intravenous perioperative heparinisation with 15,000 IU of unfractionated heparin, cross-clamps were placed on both renal arteries, subrenal aorta and suprarenal aorta just below superior mesenteric artery. A longitudinal incision was made in the aorta between the aortic cross-clamps. Circular aortic calcifications protruded through the aortotomy with CTAG correlation (Fig. 3). Circumferential separation of the plaque from adventitia was accomplished, and the dissection proceeded through the entire aortotomy. The calcific plaques extending to the left renal artery were disected similarly. The aortotomy was closed with a primary suture using Prolene 4/0. The suprarenal clamp duration was 23 min. Identically, an endarterectomy of both common ­iliac arteries orifice was performed through a short incision. After aortic cross-clamps removal, both common iliac arteries had strong, palpable pulsation. The rest of the surgery progressed routinely. The total perioperative blood loss was 3,000 mL. A cell saver system was used during the procedure. The postoperative period was uneventful. Renal Doppler‘s ultrasonography of the left kidney immediately after the procedure showed good kidney perfusion. The patient was discharged on the eighth postoperative day with excellent renal parameters (creatinine 52 µmol/L), normal left kidney perfusion, and a daily dose of 100 mg acetylsalicylic acid and 20 mg atorvastatin. The patient is without limiting claudications on both lower extremities. Currently, we have a 12-month follow-up with the patient.

Discussion

The first description of the abdominal aorta‘s intraluminal calcifications affecting the renal and mesenteric arteries, also known as CRA, by Qvarfordt et al., dates back to 1984 [2]. Since then, very few single reports case series have been published [7,8]. CRA estimated prevalence ranges between 0.6 and 1.8% with no significant difference in gender distribution [9]. Baldaia et al. conducted a systematic electronic search of the literature using MEDLINE via PubMed and Embase databases for the past 20 years. Their results found 124 published cases of patients diagnosed and treated with CRA [10]. Approximately 50% of patients are presented with claudication, 41.7% with renovascular hypertension, and 9.1% with visceral ischemia [11,12].

The pathophysiology behind CRA is not fully understood. Common risks for cardiovascular disease do not explain its pathogenesis. The plaques typically grow more aggressively into the lumen than those observed in typical athero­sclerotic lesions [13]. Interestingly, another vascular condition with a completely different pathology called “middle aortic syndrome” affects the same parts of the aorta as CRA and can mimic CRA symptomatology. The symptomatology behind middle aortic syndrome is caused by aortal stenosis due to inflammatory hypertrophy of the adventitia and intima layer of the vessel wall [14].

Despite its high mortality and morbidity, open surgical endarterectomy as a treatment of CRA remains the most widely used therapeutical procedure [15]. Perioperative mortality ranges between 8.7–11.6% and 13.9–15.9% for postoperative complications [16]. Endovascular interventions are becoming an alternative treatment modality in selected patients with good landing zones and minimal involvement of renal or visceral arteries [17]. Novel approaches in the treatment of CRA using intravascular lithotripsy are slowly emerging and showing good efficacy and safety [18]. How­ever, due to CRA‘s rarity, the application of novel endovascular interventions in clinical medicine is slow.

 

Conclusion

CRA is a rare clinical entity. The optimal treatment for CRA has not yet been established. Endovascular treatments are slowly becoming more frequently used in carefully selected patients. Up-to-date, the gold standard treatment of CRA is surgical endarterectomy.

 

Conflict of interests

The authors declare that they have no conflict of interest related to the creation of this article, and that this article has not been published in any other journal with access to congress abstracts.