**6. Septic emboli to mesenteric vasculature**

Septic embolization to the mesenteric vessels is a serious, potentially life-threatening complication of IE [4]. Small valvular vegetations can break off, enter the circulation, and become lodged in the mesentric arteries, endangering blood supply to the small intestine and colon [91, 92]. Compared to other organ systems affected by metastatic or embolic events of IE, mesenteric embolization is relatively rare, constituting approximately 3% of SE [2]. However, general surgeons must consider this entity on their differential list of causes leading to acute bowel ischemia. In terms of vascular distribution, the inferior mesenteric artery (IMA) involvement is much less common than SE to the superior mesenteric artery (SMA, approximately 3% versus <1%, respectively) [93]. Clinical indications for operative abdominal intervention following mesenteric SE are similar to those for other acute abdominal emergencies and have been discussed elsewhere [94, 95].

Septic embolism involving the mesenteric vessels can also be associated with mycotic aneurysms [96]. Pathophysiology involves embolization of small valvular vegetation fragments to the arterial vasa vasorum or the intraluminal space with subsequent extension of the infection through the intima and outward through the media of the vessel wall [58, 97]. This process gradually weakens the arterial wall, resulting in pathologic dilation and pseudoaneurysm formation [58]. Depending on the anatomic characteristics of the pseudoaneurysm, and the presence versus absence of associated distal embolization/thrombosis, management may include resection or vascular bypass of the lesion [98]. Inherent to the nature of pseudoaneurysms secondary to SE, high complication rate and/or mortality may be encountered [98].

In one unusual case, *Streptococcus bovis* endocarditis was reported to be associated with SE to the superior mesenteric artery (SMA) resulting in a mycotic aneurysm. Computed tomography (CT) imaging demonstrated a saccular aneurysm of the SMA and follow-up angiography showed evidence of SE to the left femoral artery [99]. A duplex ultrasound further characterized the femoral artery lesion as an intravascular mass at the left femoral artery bifurcation. Echocardiography confirmed mitral valvular vegetations. The patient underwent surgical resection of the mesenteric aneurysm, embolectomy of the femoral artery, as well as mitral valve replacement procedure [99].

In another report, *Coxiella burnetii* endocarditis led to concurrent SMA embolism and renal infarction. The patient presented with acute abdominal and flank pain, with subsequent CT of the abdomen demonstrating acute infarct of the right kidney and suspected SMA emboli [100]. The patient underwent laparotomy and successful SMA balloon thromboembolectomy. Subsequent TEE demonstrated a heterogeneous, mobile aortic valve mass. The patient was started on triple antibiotic regimen of vancomycin, gentamicin, and ceftriaxone. Subsequent aortic valve replacement was performed using a pericardial valve, with good long-term clinical outcome [100].
