記住我
CASE REPORT
Year : 2022 | Volume
: 9
| Issue : 5 | Page : 397-400
Isolated giant infrarenal abdominal aortic aneurysm with dissection: Case report of an extremely rare entity
Divij Jayant, Arunanshu Behera, Cherring Tandup, Satish Subbiah Nagaraj, Saroj Yadav
Department of General Surgery, PGIMER, Chandigarh, India
Correspondence Address:
Prof. Arunanshu Behera
Department of General Surgery, PGIMER, Chandigarh
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/ijves.ijves_54_22
Although abdominal aortic aneurysm (AAA) is common in the atherosclerotic aorta in the elderly, isolated AAA (IAAA) is a rare entity. Only few case reports of IAAA associated with concomitant dissection are reported in the literature. Here, we present a case of a middle-aged male who presented with abdominal pain with stable hemodynamics. Abdominal examination revealed a pulsatile mass in the left paraumbilical region. CT angiography of the abdomen revealed an isolated infrarenal AAA with dissection extending into the bilateral common iliac arteries and an eccentric partial thrombosis of the false lumen. The patient underwent successful open aneurysmorrhaphy with PTFE graft. Postoperative course was uneventful, and the patient was discharged to follow up in clinics.
Keywords: Aneurysmorrhaphy, contained rupture, infrarenal aortic aneurysm, isolated infrarenal aortic dissection
A true aortic aneurysm is defined as the dilation of all the layers (intima, media, and adventitia) of the aortic wall. Based upon morphology, the aneurysm can be fusiform-with symmetric and circumferential dilation (75%) or saccular-localized dilation (25%).[1] Aortic dissection is the most common form of acute aortic syndrome characterized by an intimal tear leading to the separation of intima and media by a false lumen of blood. Aortic dissection limited to the abdominal aorta without the involvement of the thoracic aorta is called isolated abdominal aortic dissection (IAAD).[2] IAAD is divided into suprarenal and infrarenal types based on the location. Suprarenal aortic dissections can involve celiac, mesenteric, and renal arteries leading to visceral and mesenteric ischemia. Infrarenal IAAD can extend distally to involve iliac arteries (16.4%)[3] leading to pelvic and lower limb ischemia as noted in this index case, however, there was no evidence of ischemia of pelvic and lower extremities in this index case in spite of the involvement of bilateral common iliac arteries (CIAs). The giant aneurysm with dissection in the infrarenal aorta with contained ruptured was successfully managed with open aneurysmorrhaphy and graft conduit.
Case ReportA 52-year-old laborer male, a reformed smoker with a history of 15 pack years, a known hypertensive and type II diabetic on regular medication, presented with complaints of pain abdomen for 2 months which was insidious in onset, periumbilical and lower abdomen, dull-aching in character, radiating to the lower back, and not related to meals. There was no history of nausea, vomiting, constipation, melena, breathlessness or chest pain, palpitation, transient vision loss, headache, or dizziness. There is no history of trauma or surgical/endovascular intervention. There is no history of similar conditions or any connective tissue disorders in the family. On examination, he was conscious and oriented with a blood pressure of 130/86 mmHg in the right arm, a pulse rate – 86/min regular, and a respiratory rate of 18/min. All peripheral pulses were palpable with intact radio-radial synchrony, without radio-femoral delay. There was no pallor, pedal edema, or lymphadenopathy. There were no rashes or cutaneous lesions suggesting connective tissue disorders. Cardiorespiratory examination was normal. Abdominal examination revealed a 10 cm × 10 cm pulsating lump extending from 5 cm above the umbilicus to 2 cm below it. The lateral margins were clearly delineated; however, the craniocaudal margins were not demarcated properly. Cardiology evaluation revealed a normal electrocardiogram, echocardiogram showed mild TR, with a left ventricular ejection fraction of 55%–60%. Other hematological and biochemical examinations were within normal limits. The contrast-enhanced computed tomography (CECT) scan showed tortuous abdominal aorta with aneurysmal dilatation of the infrarenal aorta and bilateral CIA, starting 3.6 cm distal to the origin of renal arteries, just below the origin of inferior mesenteric artery (IMA) with dissection flap within extending into bilateral CIA till bifurcation into external iliac arteries (EIA) and internal iliac artery (IIA) [Figure 1] and [Figure 2]. Anteriorly located false lumen was filled with eccentric partial thrombus [Figure 1] and [Figure 2]. The neck of the sac was 3.7 cm. The maximum caliber of the dilated segment was 6.3 cm while that of the true and false lumen was 1.2 cm and 2.9 cm, respectively. Arterial tree below the bilateral femoral arteries was normal. The patient was taken up for surgery. Intraoperatively, there was 15 cm × 15 cm aneurysm sac in the infrarenal abdominal aorta extending 4 cm distal to the left renal vein to the bifurcation of bilateral CIA [Figure 3]. No pulsation was noted in IMA. Bilateral ureters were identified and separated from the sac. The proximal control was taken at the abdominal aorta distal to the left renal vein, whereas distal control was taken at bilateral EIA and IIA. The sac was opened, and approximately 500 g of the blood clot was removed and sent for culture. Dacron 18 mm × 9 mm bifurcated graft was used as conduit with inflow from infrarenal aorta and outflow to right EIA and left distal CIA. Right IIA was ligated. The patient was transfused 4 packed red blood cells intraoperatively. Intraoperative hemodynamic parameters were stable. The patient was extubated and shifted to the postoperative recovery room. He did well postoperative and was discharged after 4 days. On 3-month follow-up, he is doing well.
Figure 1: (a and b) Infrarenal aortic aneurysm involving bilateral common iliac arteries, (c) Yellow arrow: Dissection flap with true lumen, yellow arrow: False lumen, red arrow: Intramural hematoma, green arrow: Left ureter
Figure 2: (a) Yellow arrows: Infrarenal aneurysm with involvement of right common iliac artery with intramural hematoma, (b) Yellow arrow: Extension of aneurysm to right common iliac artery till bifurcation with hematoma, (c) Yellow arrow: Extension of aneurysm to left common iliac artery till bifurcation with surrounding hematoma
Figure 3: (a) Blue arrow: Infrarenal aorta looped, yellow arrow-infrarenal aortic aneurysm, red arrows: Aneurysm extending to involve bilateral CIA, (b) Yellow arrow: Infrarenal to graft anastomosis, white arrow: Aneurysm sac: (c) Yellow arrow: Graft to left common iliac anastomosis, green arrow: Left ureter Discussion Aortic dissection is classified as Stanford type A (involving the ascending aorta) and type B (distal aorta). Aortic dissection limited to the abdominal aorta without the involvement of the thoracic aorta is called IAAD.[2] They can be spontaneous (87%), traumatic (6.25%), or iatrogenic (6.25%). Spontaneous IAAD is a rare entity and constitutes only 1.3% of all aortic dissections.[3] Major risk factors associated with spontaneous dissections are aortic wall degeneration due to hypertension, aortic aneurysm, mycotic aneurysm, fibromuscular dysplasia, connective tissue disorders (Marfan's syndrome and Ehlers–Danlos syndrome), vasculitis, illicit drug abuse (cocaine and amphetamines), and pregnancy. It is commonly encountered in the elderly population (mean age: 67.7 years) with males affected three times more common than females.[3] However, those with connective tissue disorders may present at an early age. IAAD is divided into suprarenal and infrarenal types based on location. Suprarenal aortic dissections can involve celiac, mesenteric, and renal arteries leading to visceral and mesenteric ischemia. Infrarenal IAAD is rare and can extend distally to involve iliac arteries with an incidence of 16.4% and can present with pelvic and lower limb ischemia.[3] Theoretical risk of spinal ischemia and infarction is present if it involves the Artery of Adamkiewicz More Details. Approximately, 10%–15% of cases of IAAD can lead to contained (80%) or free (retroperitoneal or intraperitoneal) rupture leading to hemorrhagic shock. The risk of rupture correlates with the size of the aneurysm, rate of growth, strength of false lumen, and blood flow rate. Asymptomatic chronic dissections are a rare presentation and ultimately lead to aneurysm formation with chronic mesenteric, visceral, or lower limb claudication. However, the risk of aneurysm development is not well known. IAAD can be associated with both aneurysmal (28%) as well as nonaneurysmal abdominal aorta.[3] Infrarenal abdominal aortic aneurysm (AAA) is the most common AAA. Approximately 20% of AAA is associated with the CIA aneurysm (CIAA). Therefore, the CIAA is considered to be an extension of the abdominal aortic aneurysmal disease.
Ninety percentage of the patients present with acute abdominal pain radiating to the back of tearing and ripping nature. Nonspecific symptoms may lead to a delayed and missed diagnosis. Aortic dissections are divided into hyperacute (<24 h), acute (2–7 days), subacute (8–30 days), and chronic (>30 days) based upon the duration at presentation.[1] Nondissecting aneurysm presenting with pulsatile or nonpulsatile abdominal mass is the most frequent examination finding. Dissection may lead to pulse deficit and variable blood pressure. Others may present with features of mesenteric ischemia or paraparesis.
Diagnosis of IAAD is primarily based on imaging findings. Ultrasound of the abdomen is the initial imaging modality which shows the location, size of the aneurysm, true and false lumen, flow rate within the false and true lumen, and intramural thrombosis with a sensitivity of 70%–80% and specificity of 100%.[4] As it is limited by operator dependence, body habitus and poor depiction of the extent of the dissection, multidetector computed tomography angiography with intravenous contrast is highly sensitive and specific for the diagnosis of aortic dissection and is considered the investigation of choice.[4] It can diagnose, determine true and false lumen, locate intimal tear, determine the extent of dissection, classify the type of dissections, and evaluate for distal complications and can help in determining surgical/endovascular plans. Magnetic resonance angiography is used only in selected cases of contrast allergy or deranged renal functions and the long imaging time for emergency patients and its availability are the limiting factors. Digital subtraction angiography is reserved for endovascular repair rather than diagnosis.
Classic findings of a ruptured AAA on a CT scan include retroperitoneal hematoma, discontinuity in circumferential calcification, and frank contrast extravasation. An indistinct posterior aortic wall that lays over the lumbar vertebra signifies a contained rupture “The draped aorta sign.” Features of impending rupture include increased in aneurysm size (>7 cm diameter or >10 mm increase per year) and irregularity in aortic wall calcifications. A crescent-shaped area of hyperattenuation within a thrombus “crescent sign” is also predictive of rupture.[1]
A mnemonic-based six key characteristic features (DISSECT) as proposed by the DEFINE group is used to supplement the traditional classification for clinical decision-making.[5] These are duration, intimal tear location, size of dissected aorta, extent of dissection, complications, and thrombosis. Acute abdominal emergency should be managed medically with resuscitative measures, antihypertensives, opiate analgesics with the goal of lowering blood pressure, heart rate, and alleviating pain. Definite treatment options include endovascular or surgical repair depending on the presentation, anatomy of abdominal aortic dissection, and experience of the surgeons. Without treatment, the mortality rate is 1%–2% per h over the first 24 h with 30-day mortality >50%.[1] Indications for immediate repair include malperfusion, including visceral or extremity ischemia; refractory pain despite the best medical treatment; rupture or imminent rupture; maximal aortic diameter >3 cm; rapid growth >5 mm/6 months or >10 mm/year; and anatomic suitability.[6]
There is an increasing trend to perform endovascular aortic repair (EVAR) compared to surgery in recent years.[7] Due to the rarity of IAAD, data regarding the optimal approach to the disease is scarce. In a meta-analysis of 92 patients with abdominal aorta dissection, endovascular treatment was associated with lower mortality and major complication rates (2%) compared to surgery (5% in-hospital mortality and 6% perioperative complications).[8] Therefore, EVAR should be considered a good alternative to the surgery for treatment of IAAD. Bare-metal stent has a better technical success rate (100%) and long-term side branch patency (100% at 2-year follow-up) compared to the covered stent graft. Hence, bare-metal stents are preferred over covered stent grafts for the treatment of IAAD without aneurysmal dilation.[9] In cases of AAA associated with IAAD involving the iliac arteries, bifurcated aortoiliac stent grafts were preferred in the past.[9] However, during follow-up, up to 37 patients showed graft occlusion on subsequent follow-up at 4 years.[10] Hence, bifurcated stent graft should be avoided. Surgical options include aortoiliac or aortobifemoral bypass.[11] Nonsurgical and nonendovascular candidates can be offered conservative medical treatment with imaging follow-up. The guidelines for follow-up imaging and intervening in chronic dissections, however, are not as robust. Chronic aortoiliac dissections with lower limb claudication should be considered for repair similar to the atherosclerotic aortoiliac disease.
ConclusionGiant infrarenal AAA with dissection is a rare entity with only a few reported cases and requires thorough evaluation with CECT and medical management to control blood pressure and rule out ischemia, rupture, and prompt endovascular or surgical management.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal patient identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
留言 (0)