Extra-anatomic Bypass from Right Common Iliac Artery for Superior Mesenteric Artery Thrombosis in a Post-thrombectomy Patient: A Case Report

Abstract

Superior mesenteric artery occlusion caused by atherosclerosis superimposed with long segment thrombosis in a 54 year old male who previously underwent a resection-anastomosis and thrombectomy procedure was treated by extra anatomic bypass grafting. The abdominal aorta could not be used for inflow due to marked adhesions from previous surgery and severe atherosclerotic changes in the wall. A vein graft was bypassed from the right common iliac artery to the superior mesenteric artery to provide effective reperfusion.

Introduction

Mesenteric occlusion, though rare, is a potentially life threatening condition and its incidence has been rising over the years. Early diagnosis is vital due to the high mortality rate, which increases with delays attributed to vague symptomatology and non-specific clinical findings coupled with limitations in diagnostic tests. Mesenteric ischemia is a common manifestation of visceral atherosclerosis and mesenteric artery thrombosis has the highest mortality rate of all causes of mesenteric ischemia [1].

Various surgical techniques are employed for revascularization in mesenteric thrombosis such as thromboendarterectomy, re-implantation of the mesenteric vessels into the adjacent aorta, transaortic thromboendarterectomy as well as aortovisceral bypass with vein or prosthetic grafts. Here we present a case where bypass grafting was done from the right common iliac to the superior mesenteric artery (SMA) in a patient who previously underwent a superior mesenteric artery thrombectomy.

Case Report

A 54 year old male presented with complaints of abrupt onset abdominal pain of diffuse and crampy nature. He also had two to three episodes of dark coloured stool over the preceding 2 days. He was a diabetic and hypertensive for which he was taking regular medication. He also had a history of heart failure with atrial fibrillation, and was on treatment with digoxin. He previously underwent a resection and anastomosis of gangrenous bowel loops of the small intestine and a thrombectomy of the superior mesenteric artery, at a local hospital 2 months prior to presentation.

On clinical examination his pulse rate was 90 beats per minute, with an irregularly irregular rhythm and blood pressure was 110/70 mm Hg. A midline scar from previous laparotomy was seen, mild tenderness in the left iliac region elicited, bowel sounds were heard and on rectal examination the examining finger stained black. On laboratory investigation his haemoglobin was 9.7 g/dl and the rest of the routine investigations were within normal limits. Ultrasonography was normal except for oedematous small bowel loops. Upper GI scopy showed congestive gastropathy with erosive gastritis. Coronary angiogram revealed atherosclerotic ectatic coronary artery disease and on abdominal aortic injection and selective SMA injection-long segment disease with superimposed thrombus in SMA was revealed (Fig. 1).

Fig. 1.

Aortogram showing superior mesenteric artery (white arrow) with long segment thrombosis (yellow arrows) in the main trunk

The patient was taken up for a planned surgery. Extensive adhesions were present from the previous surgery and it was difficult to expose the aorta. The SMA was completely occluded from its origin to bifurcation. Right common iliac to SMA reverse long saphenous vein grafting was done. Good pulse was felt in the SMA and blush seen post-grafting. The post-operative period was uneventful and he recovered well. He was discharged 12 days after the surgery with no residual symptoms (Figs. 2 and 3).

Fig. 2.

Intra-operative photograph showing reverse long saphenous vein graft (black arrow) bypassed from right common iliac artery (white arrow)

Fig. 3.

Intra-operative photograph showing reverse long saphenous vein graft (black arrow) bypassed to superior mesenteric artery (white arrow)

Discussion

The most common pre-existing pathology in patients with mesenteric thrombosis is atherosclerosis. Other risk factors include arrhythmias, hypovolemia, congestive heart failure, recent myocardial infarction, valvular disease and advanced age. A patient diagnosed with mesenteric thrombosis, should undergo surgery because of the risk of sepsis, bowel infarction and possible death. Unlike embolic events that occur more frequently in arterial branches causing limited bowel ischaemia with better survival, thrombosis occurs more often at the vessel origin, resulting in extensive bowel involvement.

A review of the cumulative experience in the surgical management of chronic visceral ischemia by Cunningham et al., identified 74 patients whose primary reconstruction used transaortic endarterectomy or antegrade bypass. The perioperative mortality rate (12.2%) and the incidence of complications was the same with either approach [2].

In the retrospective analysis by Patel et al. [3] on single vessel bypass surgery conducted for symptomatic chronic mesenteric ischaemia in six patients; all had disappearance of symptoms and weight gain on bypassing the occluded segment. They reported no major complications or death and stressed that urgent revascularization is indicated in all symptomatic patients to prevent complications such as intestinal infarction.

A study conducted by Cho et al. [4] identified 48 patients who underwent mesenteric artery reconstruction for atherosclerotic mesenteric ischaemia, either by bypass grafting or endarterectomy (local and transaortic).a perioperative mortality rate of 52% was seen only in patients with acute mesenteric ischaemia compared to patients with chronic mesenteric ischaemia. The probability of long term survival was 77% at 5 years. They concluded that long term patency and symptom free survival can be expected after successful reconstruction.

According to Wichterman and Stansel [5] extra-anatomic bypass grafts from the external iliac artery could be used to simplify splanchnic artery revascularization and avoid concomitant atherosclerotic disease in the adjacent aorta complicating aortovisceral bypasses. Odagiri et al. [6] reported a case of mesenteric ischaemia caused by SMA obstruction associated with acute aortic dissection where SMA bypass was performed successfully from the right common iliac artery with good patient outcome.

As accurately summed up by Patel et al. [3] the precise choice of operation depends not only on the specific clinical circumstances but also on the judgement and experience of the operating surgeon.