Splenic Artery-to-Superior Mesenteric Artery Bypass for Chronic Mesenteric Ischemia

Abstract

Chronic mesenteric ischemia (CMI) is a serious vascular condition that if left untreated may progress to acute ischemia resulting in bowel necrosis and high surgical morbidity/mortality rates. Elective intervention has been shown to prevent this progression and relieve symptoms. Current open surgical intervention involves arterial bypass using a vein or synthetic graft conduit with the inflow originating from the aorta or iliac artery. In some circumstances, the splenic artery provides an additional treatment option for revascularization of the superior mesenteric artery. In certain cases, the splenic artery has several advantages over traditional surgical options. The splenic artery is an arterial conduit much like the internal mammary artery used in coronary artery bypass grafting. These grafts are known for their long-term patency and in selected clinical circumstances are preferred over venous grafts. Because the splenic artery has a natural inflow, only a single vascular anastomosis at the outflow vessel (the SMA) is necessary. This lessens the risk of anastomotic stenosis by decreasing the number of anastomoses created and it makes the procedure shorter in duration. The fact that the inflow is provided by the splenic artery makes cross-clamping of the aorta unnecessary, thereby lessening the risk of producing cardiac ischemia and declamping hypotension. A disadvantage is the risk of splenic ischemia with the possible need for splenectomy. The majority of individuals will have adequate collateral supply to the spleen via the short gastric arteries. The risk to the patient of splenectomy versus the benefits of a less complicated arterial reconstruction with avoidance of aortic cross-clamping must be weighed on a case-by-case basis. Preventing the progression to acute mesenteric ischemia with its increased mortality by timely restoration of adequate vascular supply is an important principle in treating patients with CMI. Controversy still exists over the best treatment option for these patients, whether it be antegrade versus retrograde bypass, single-vessel versus multivessel reconstruction, or open surgical repair versus endovascular intervention. In selected patients, the use of the splenic artery can be considered as an additional option for arterial reconstruction of the SMA.