Local thrombolytic therapy in acute mesenteric ischemia

ACR Appropriateness Criteria® Radiologic Management of Mesenteric Ischemia: 2022 Update

Mesenteric ischemia is a serious medical condition characterized by insufficient vascular supply to the small bowel. In the acute setting, endovascular interventions, including embolectomy, transcatheter thrombolysis, and angioplasty with or without stent placement, are recommended as initial therapeutic options. For nonocclusive mesenteric ischemia, transarterial infusion of vasodilators, such as papaverine or prostaglandin E1, is the recommended initial treatment. In the chronic setting, endovascular means of revascularization, including angioplasty and stent placement, are generally recommend, with surgical options, such as bypass or endarterectomy, considered alternative options. Although the diagnosis of median arcuate ligament syndrome remains controversial, diagnostic angiography can be helpful in rendering a diagnosis, with the preferred treatment option being a surgical release. Systemic anticoagulation is recommended as initial therapy for venous mesenteric ischemia with acceptable rates of recanalization. If anticoagulation fails, transcatheter thrombolytic infusion can be considered with possible adjunctive placement of a transjugular intrahepatic portosystemic shunt to augment antegrade flow. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Prediction of need for bowel resection in acute superior mesenteric artery occlusion: A retrospective study of 48 Japanese patients

Aim

This study aimed to predict cases of acute superior mesenteric artery (SMA) occlusion requiring bowel resection using occlusion site and time from symptom onset to diagnosis at five Japanese institutions. Advances in imaging, endovascular treatment, and perioperative management have improved the clinical outcomes of patients with acute SMA occlusion; however, in clinical practice it remains difficult to effectively determine patients requiring bowel resection.

Methods

We retrospectively analyzed the data of 48 patients (mean age: 82.5 y; male: 37.5%) diagnosed with acute SMA occlusion between June 2009 and August 2018. Background data of patients who required and did not require bowel resection were compared. A multivariable predictive model was developed using the time from symptom onset to diagnosis and whether SMA occlusion was proximal, including the origin of the middle colic artery.

Results

Fifteen patients (31.3%) died during the hospital stay. Atrial fibrillation (83.3%) was the most common comorbidity. The median time from symptom onset to diagnosis was 13.0 (interquartile range, 4.75-24.0) h. Laparotomy, bowel resection, and thrombus embolectomy were performed in 41 (85.4%), 26 (54.2%), and 21 (43.8%) patients, respectively. A logistic regression model achieved 78.6% sensitivity in predicting cases not requiring bowel resection. Proximal occlusion was significantly associated with the requirement for bowel resection (P = .039).

Conclusion

The time from symptom onset to diagnosis and occlusion site contributed to high sensitivity in determining the need for bowel resection in patients with acute SMA occlusion. Further prospective studies are warranted to investigate the clinical impact of this model.

Acute mesenteric ischemia (Part II) - Vascular and endovascular surgical approaches

The modern treatment of acute mesenteric ischemia (AMI) requires seamless collaboration of gastrointestinal surgeons, vascular surgeons, and interventional radiologists. The treatment strategy is straightforward aiming at rapid restoration of blood flow to the intestine. Bowel resection is performed on demand. The first thing to consider is the patient's clinical condition at presentation, whether there are signs of peritonitis or not, and whether the patient is hemodynamically stable or not. Second, there are four etiologies of AMI that need to be distinguished as they differ in treatment: superior mesenteric artery embolism, mesenteric arterial occlusive disease, mesenteric venous thrombosis, and non-occlusive mesenteric ischemia. In this review, we describe the basic vascular and endovascular treatment modalities accompanied by a simple algorithm for the various situations in AMI. Furthermore, the indications for damage control and primary definitive surgery are discussed.

Mechanical Recanalization for Acute Embolic Occlusion at the Origin of the Superior Mesenteric Artery

Purpose:

We report a combined technique consisting of thrombectomy and thromboaspiration for the treatment of acute embolic occlusion of the superior mesenteric artery (SMA) at the origin.

Case:

A 90-year-old female with chronic atrial fibrillation had a sudden onset of abdominal pain and hematochezia due to acute embolic occlusion at the origin of the SMA. Computed tomographic findings showed reversible bowel wall ischemia. We performed mechanical thrombectomy using the Solitaire FR revascularization device, a self-expanding and fully retrievable stent-based thrombectomy system for acute intracranial large artery occlusion, combined with manual aspiration through a 6F guiding sheath placed at the SMA origin via a right brachial approach. Prompt and complete recanalization of the SMA was obtained without distal embolism, and intestinal necrosis was avoided.

Conclusion:

Combined endovascular procedures of mechanical thrombectomy using the Solitaire FR with thromboaspiration may allow prompt recanalization, clot removal, and prevention of distal embolism and therefore would be a new therapy for acute embolic occlusion at the origin of the SMA.

Mesenteric ischemia: Pathogenesis and challenging diagnostic and therapeutic modalities

Mesenteric ischemia (MI) is an uncommon medical condition with high mortality rates. ΜΙ includes inadequate blood supply, inflammatory injury and eventually necrosis of the bowel wall. The disease can be divided into acute and chronic MI (CMI), with the first being subdivided into four categories. Therefore, acute MI (AMI) can occur as a result of arterial embolism, arterial thrombosis, mesenteric venous thrombosis and non-occlusive causes. Bowel damage is in proportion to the mesenteric blood flow decrease and may vary from minimum lesions, due to reversible ischemia, to transmural injury, with subsequent necrosis and perforation. CMI is associated to diffuse atherosclerotic disease in more than 95% of cases, with all major mesenteric arteries presenting stenosis or occlusion. Because of a lack of specific signs or due to its sometime quiet presentation, this condition is frequently diagnosed only at an advanced stage. Computed tomography (CT) imaging and CT angiography contribute to differential diagnosis and management of AMI. Angiography is also the criterion standard for CMI, with mesenteric duplex ultrasonography and magnetic resonance angiography also being of great importance. Therapeutic approach of MI includes both medical and surgical treatment. Surgical procedures include restoration of the blood flow with arteriotomy, endarterectomy or anterograde bypass, while resection of necrotic bowel is always implemented. The aim of this review was to evaluate the results of surgical treatment for MI and to present the recent literature in order to provide an update on the current concepts of surgical management of the disease. Mesh words selected include MI, diagnostic approach and therapeutic management.

TLR2 modulates antibodies required for intestinal ischemia/reperfusion-induced damage and inflammation

In multiple clinical conditions, including trauma and hemorrhage, reperfusion magnifies ischemic tissue damage. Ischemia induces expression of multiple neoantigens, including lipid alterations that are recognized by the serum protein, β2-glycoprotein I (β2-GPI). During reperfusion, binding of β2-GPI by naturally occurring Abs results in an excessive inflammatory response that may lead to death. As β2-GPI is critical for intestinal ischemia/reperfusion (IR)-induced tissue damage and TLR2 is one of the proposed receptors for β2-GPI, we hypothesized that IR-induced intestinal damage and inflammation require TLR2. Using TLR2(-/-) mice, we demonstrate that TLR2 is required for IR-induced mucosal damage, as well as complement activation and proinflammatory cytokine production. In response to IR, TLR2(-/-) mice have increased serum β2-GPI compared with wild-type mice, but β2-GPI is not deposited on ischemic intestinal tissue. In addition, TLR2(-/-) mice also did not express other novel Ags, suggesting a sequential response. Unlike other TLRs, TLR2(-/-) mice lacked the appropriate Ab repertoire to induce intestinal IR tissue damage or inflammation. Together, these data suggest that, in addition to the inflammatory response, IR-induced injury requires TLR2 for naturally occurring Ab production.

Diagnosis and management of ischemic colitis

The clinical presentation and outcome of ischemic colitis have a wide spectrum. Impaired perfusion of blood to the bowel from a variety of causes is the underlying pathophysiology. The presence of diarrhea, abdominal pain, and mild lower gastrointestinal bleeding should prompt consideration of ischemic colitis as a cause. Although many laboratory tests and radiographic images may suggest the diagnosis, endoscopic visualization of the colonic mucosa with histologic analysis of biopsies is the gold standard for identification of colonic ischemia. Many cases are transient and resolve without any complications. Medical therapy for chronic ischemia has been anecdotally proven but not carefully studied. Complications of ischemic colitis can include bowel perforation, peritonitis, persistent bleeding, protein-losing colonpathy, and symptomatic intestinal strictures. Surgical resection of the affected segment should be considered early to minimize adverse outcomes. This review describes the etiology, pathophysiology, clinical features, diagnostic approach, and management of ischemic colitis.

Initial transcatheter thrombolysis for acute superior mesenteric venous thrombosis

AIM: To determine the optimal initial treatment modality for acute superior mesenteric vein thrombosis (ASMVT) in patients with circumscribed peritonitis.

METHODS: A retrospective review was made of the Vascular Surgery Department’s medical records to identify adult patients (≥ 18 years old) presenting with circumscribed peritonitis and diagnosed with ASMVT by imaging or endoscopic examination. Patients were selected from the time period between October 2009 and October 2012 to assess the overall performance of a new first-line treatment policy implemented in May 2011 for patients with circumscribed peritonitis, which recommends transcatheter thrombolysis with local anticoagulation and endovascular mechanical thrombectomy. Of the 25 patients selected for study inclusion, 12 had undergone emergency surgical exploration (group 1) and 13 had undergone the initial catheter-directed thrombolysis (group 2). Data extracted from each patient’s records for statistical analyses included method of diagnosis, symptoms, etiology and risk factors, thrombus location, initial management, morbidity, mortality, duration and total cost of hospitalization (in Renminbi, RMB), secondary operation, total length of bowel resection, duration of and findings in follow-up, and death/survival.

RESULTS: The two treatment groups showed similar rates of morbidity, 30-d mortality, and 1-year survival, as well as similar demographic characteristics, etiology or risk factors, computed tomography characteristics, symptoms, findings of blood testing at admission, complications, secondary operations, and follow-up outcomes. In contrast, the patients who received the initial non-operative treatment of transcatheter thrombolysis had significantly shorter durations of admission to symptom elimination (group 1: 18.25 ± 7.69 d vs group 2: 7.23 ± 2.42 d) and hospital stay (43.00 ± 13.77 d vs 20.46 ± 6.59 d), and early enteral or oral nutrition restoration (20.50 ± 5.13 d vs 8.92 ± 1.89 d), as well as significantly less total length of bowel resection (170.83 ± 61.27 cm vs 29.23 ± 50.24 cm) and lower total cost (200020.4 ± 91505.62 RMB vs 72785.6 ± 21828.16 RMB) (P < 0.05 for all). Statistical analyses suggested that initial transcatheter thrombolysis is correlated with quicker resolution of the thrombus, earlier improvement of symptoms, stimulation of collateral vessel development, reversal of intestinal ischemia, receipt of localizing bowel resection to prevent short bowel syndrome, shorter hospitalization, and lower overall cost of treatment.

CONCLUSION: For ASMVT patients with circumscribed peritonitis, early diagnosis is key to survival, and non-operative transcatheter thrombolysis is feasible and effective as an initial treatment.