Introduction

The aortic dissection is a condition when the tear of intima (entry) leads to pathological separation of the aorta layers, resulting in forming two blood flows: in a true and false lumen. The additional area connecting two lumens (secondary entry) can appear on different levels. The false lumen could be formed between various layers of the aorta wall and have different diameters including the considerable wide ones. In these cases the true lumen of aorta performs significant stenosis which requires surgical treatment.

According to the currently used Stanford classification and as far as the aortic dissection location is concerned, there are two types of diseases – A and B (fig. 1). Type A dissection is related to ascending aorta whereas type B concerns aorta section below its subclavian branch. The A type accounts for serious cardiosurgery problems is treated as a matter of urgency. The type B dissection is treated with medical therapy but in case of risk of rupture or abdominal organs and lower limbs ischemia the surgical intervention should be taken into consideration. The most commonly applied method is endovascular stent-graft placement, covering the place of damaged intima [1]. The aim of the surgery is to increase the true lumen diameter and cause the false lumen thrombosis in the area of dissection [2-5].

The important clinical problem concerning the patients after the stent-graft placement is a malperfusion of organs supplied with arterial blood from the obliterated false lumen area.

The study describes the treatment of a female patient suffering from B type dissection after the endovascular stent-graft (Zenith type) placement in thoracic aorta. In this case the celiac trunk was blood supplied from both lumens, true and false, and the left kidney by two renal arteries coming from the false lumen.

Case report

A 53-year-old patient was admitted to the clinic on 23^rd March 2011 in order to continue dissection of thoraco-abdominal aorta treatment. The review proved concomitant diseases presence i.e. arterial hypertension treated since 2006, dyslipidemia, obesity and iron deficiency anemia. Pulmonary thromboembolism and left lower extremity deep vein thrombosis were noticed in the patient’s medical history. Moreover, the patient mentioned the 15 years nicotine addiction and strong family history in cardiovascular diseases.

In 2006 the patient underwent endovascular ‘Zenith’ stent-graft placement operation over the thoracic aorta due to aortic dissection and aneurysmal aortic dilatation to 81 mm. After operation the process of thrombosis in the false lumen over the thorax was evident. Wide secondary entry, supplying blood to the false lumen was localised on the celiac trunk level. In order to eliminate the inflow to the false lumen, the patient underwent celiac trunk angioplasty with covered stent placement at the beginning of March 2011. In the angio-computed tomography examination the stent patency was correct and the inflow on the celiac trunk ostium level was eliminated. This examination showed also another secondary entry in the left common iliac artery, which maintained the false lumen patency. Two left renal arteries were supplied by blood from this area.

Considering the fact that angio-computed tomography examination revealed an increase of abdominal aorta diameter to 42 mm, significant stenosis of true lumen and insufficient inflow to the left kidney, the patient was planned to have surgical treatment. The vascular graft placement with the beginning in the left external iliac artery and ending in the two left renal arteries and stent-graft implantation to the left common iliac artery were needed to eliminate the false lumen with simultaneous preserving of left renal perfusion. The operation was performed on 25^th March 2011.

The vascular graft was composed of the patient’s own vessel and the PTFE (polytetrafluoroethylene) graft with 6 mm diameter. Approximately 25 cm of saphena magna was taken and cut into two halves. Then, they were sutured lengthwise on the ending, creating common ostium by the length of 8 mm which was connected with the 6 mm in dia­meter PTFE graft with the ‘end to end’ method. The next step was creating the vascular shunt between PTFE ending and the left external iliac artery with using the method ‘end to side’. Then the both vessel parts were connected with the two left renal arteries ‘end to end’ (fig. 3).

The following angio-CT examination, which was carried out 6 days after operation, showed proper left kidney perfusion, iliac common artery stent graft patency and the lack of inflow to the false lumen. There were no complications on further clinical course. The kidney function was examined by assaying creatinine rate in plasma achieving standard results.

The patient was discharged from the clinic in a good condition with proper kidney function without abdominal organs perfusion disorders. The patient was followed up by the Vascular Surgery Clinic. The next angio-CT examination was taken after 7 months. This showed the stent-grafts and vascular graft patency.

Discussion

According to the currently used Stanford classification, the type B aortic dissection usually requires treating only with medical therapy. In this kind of treatment, the strict control of concomitant diseases, especially the arterial hypertension is essential. Surgery including endovascular stent- graft placement can be used for patients with the risk of aorta rupture or the symptomatic dissection. Surgery treatment should be chosen in case of abdominal or pelvis organs as well as lower limbs malperfusion symptoms. Endovascular stent-graft placement, as the most often chosen method of treating aortic dissection aims not only for extending true lumen diameter but also eliminates false lumen (by closing inflow into the primary entry), causes its thrombosis and mechanical stability of aorta walls [1-5]. This method efficacy reaches 98.2% in meta analysis showed by Eggebrecht group in 2006 [4].

For patients with aortic dissection, in a group with main functional arteries supplied from false lumen, the abdominal organs and lower limbs perfusion depends on the false lumen patency. In case of stent-graft placement as a method of aortic dissection treatment, the option of inflow closure to these arteries should be considered. Major complications after using endovascular treatment, which may have risk of death and require follow up treatment including also abdominal organs ischemia, occur in approximately 11.2% cases [4]. Minor complications, not requiring treatments in future i.e. for example temporary renal insufficiency occur in approximately 2.4% cases [4]. Chronic dissections treated with endovascular methods carry lower surgery risk and amount of complications than acute ones (9.1% v. 21.7%) [4]. The method which ensures continuity of flow and a proper organs function in case of complications, is vascular false lumen by-pass graft.

The best material used in vascular surgery is the patient’s own vessel. Many times it is difficult or even impossible to obtain sufficiently good autograft, both of quality and quantity. In these cases PTFE synthetic endovascular stent-grafts are used.

Described above the medical treatment enables the patients with aortic dissection to be completely cured which means maintenance of the aorta patency, eliminating the false lumen and protecting from rupturing in this area and also ensuring proper organs perfusion.

References