CT angiography followed by endovascular intervention for acute superior mesenteric artery occlusion does not increase risk of contrast-induced renal failure

The Evaluation and Management of Intestinal Ischemia

AbstractIntestinal ischemia can result from various pathologic conditions. The presentations of ischemia can range from acute to subacute and mild to severe. Diagnosis of this condition may pose challenges, particularly in the early, potentially salvageable, stages of disease. This review offers an evidence-based approach to understanding the diagnosis and management of inadequate intestinal perfusion.

Validation of computed tomography angiography using mean arterial pressure gradient as a reference in stented superior mesenteric artery

PURPOSE

The aim of this prospective study was to validate the diagnostic performance of computed tomography angiography (CTA) in endoprosthesis stenosis in the superior mesenteric artery (SMA) using mean arterial pressure (MAP) gradients during angiography as a reference method.

METHODS

Twenty-nine patients with mesenteric atherosclerotic disease underwent 45 paired measurements of endoprosthesis stenosis in the SMA with CTA and MAP gradients between March 2009 and July 2015. The grade of endoprosthesis stenosis in the SMA at CTA using the TeraRecon Aquarius workstation was correlated with MAP gradients.

RESULTS

Grade of endoprosthesis stenosis in the SMA (r = 0.37, p = 0.013) correlated with MAP gradients. The intraclass correlations between the first and second CTA rater was 0.76 (95% CI 0.56-0.87) for estimation of grade of endoprosthesis stenosis in the SMA. The area under the receiver operating characteristics curve was 0.79 for diagnosis of significant endoprosthesis stenosis in the SMA at CTA for different threshold values using MAP gradient of ≥ 10 mmHg as reference. Sensitivity, specificity and positive predictive value for endoprosthesis stenosis in the SMA ≥ 50% at CTA were 52.4% (95% CI 31.0-73.7), 87.5% (95% CI 74.3-100.0) and 78.6 (95% CI 57.1-1.00), respectively.

CONCLUSION

Grading endoprosthesis stenosis in the SMA with CTA performed fair when using trans-stenotic MAP gradient as reference. Software development towards reduction of endoprosthesis artefacts may result in more accurate CTA assessment of the narrowest part.

Review Article: Mesenteric Ischemia

PURPOSE OF REVIEW

Mesenteric ischemia (MI), both acute (AMI) and chronic (CMI), is a challenging diagnosis to make, and early diagnosis and treatment are vital to improve outcomes. This manuscript summarizes the most up to date information on diagnosis and treatment of these disorders.

RECENT FINDINGS

There have been several significant advancements in the computed tomography (CT) diagnostic imaging as well as medical and endovascular management of AMI and CMI. In appropriate populations, endovascular interventions appear superior to open surgical management with lower mortality, morbidity, and cost of care. Efficient clinical identification and targeted testing are essential to diagnose AMI and CMI. Aggressive resuscitation and early endovascular (or in select cases, surgical) intervention improve outcomes in those with AMI. In those with CMI, considering this on the differential diagnosis and imaging appropriately can identify those that might benefit from intervention and halt progression to acute episodes.

Acute mesenteric ischemia (part I) - Incidence, etiologies, and how to improve early diagnosis

Acute mesenteric ischemia (AMI) is generally thought to be a rare disease, but in fact, it is more common cause of acute abdomen than appendicitis or ruptured abdominal aortic aneurysm in patients over 75 years of age. In occlusive AMI, surgical treatment without revascularization is associated with as high as 80% overall mortality. It has been shown that early diagnosis with contrast-enhanced computed tomography and revascularization can reduce the overall mortality in AMI by up to 50%. However, only a minority of patients with AMI are being treated actively with revascularization in the United States, and the situation is very likely similar in Europe as well. What can we do to improve diagnostic performance, so that more patients get proper treatment? The diagnosis is a collaborative effort of emergency department surgeons, gastrointestinal and vascular surgeons, and radiologists. The etiological categorization of AMI should be practical and guide the therapy. Furthermore, the limitations of the diagnostic examinations need to be understood with special emphasis on computed tomography findings on patients with slowly progressing "acute-on-chronic" mesenteric ischemia.

Diagnostic value of intestinal fatty acid-binding protein for pneumatosis intestinalis

BACKGROUND

Pneumatosis intestinalis (PI) is known as a sign of a life-threatening bowel ischemia. We aimed to evaluate the utility of intestinal fatty acid-binding protein (I-FABP) in the diagnosis of pathologic PI.

METHODS

All consecutive patients who presented to our emergency department with PI were prospectively enrolled. The diagnostic performance of I-FABP for pathologic PI was compared with that of other traditional biomarkers and various parameters.

RESULTS

Seventy patients with PI were enrolled. Pathologic PI was diagnosed in 27 patients (39%). The levels of most biomarkers were significantly higher in patients with pathologic PI than those with nonpathologic PI (P < .05). Receiver operator characteristic analysis revealed that the area under the curve (AUC) was highest for I-FABP (area under the curve = .82) in the diagnosis of pathologic PI.

CONCLUSIONS

High I-FABP value, in combination with other parameters, might be clinically useful for pathologic PI.

Mesenteric ischemia

PURPOSE OF REVIEW

Diagnosis of acute mesenteric ischemia in the early stages is now possible with modern computed tomography (CT), using intravenous contrast enhancement and imaging in the arterial and/or portal venous phase. The availability of CT around the clock means that more patients with acute mesenteric ischemia may be treated with urgent intestinal revascularization.

RECENT FINDINGS

The establishment of a hybrid operation room is most important to be able to perform explorative laparotomy for evaluation of the extent of mesenteric ischemia and successful intestinal revascularization. Endovascular recanalization and stenting has become an important alternative, especially in patients with both acute and chronic thrombotic superior mesenteric artery (SMA) occlusion. Aspiration embolectomy, thrombolysis and open surgical embolectomy, followed by on-table angiography, are the treatment options for embolic SMA occlusion. Endovascular therapy may be an option in the few patients with mesenteric venous thrombosis who do not respond to anticoagulation therapy. The concept of damage-control surgery is recommended after intestinal revascularization.

SUMMARY

Intestinal revascularization in patients with arterial occlusive mesenteric ischemia reduces bowel morbidity and mortality. Observational studies report that both endovascular and open vascular therapy options are effective, but endovascular technique may be preferred in these often elderly and fragile patients.

[Acute mesenteric ischemia: do biomarkers contribute to diagnosis?]

Acute mesenteric ischemia is an emergency condition that requires immediate therapy. Despite advances in the fields of surgery and intensive therapy, the mortality of this condition remains high. This is due to the broad variability of clinical presentations and non-specific laboratory findings, which delay the diagnosis allowing the ischemia to progress and further worsening the patients' chances of survival. Thus, there is a significant need for reliable and enhanced serological markers of intestinal ischemia. The authors review the traditionally used and novel experimental serological markers for early diagnosis of mesenteric ischemia.

Diagnostic performance of plasma biomarkers in patients with acute intestinal ischaemia

BACKGROUND

The aim of this study was to evaluate the use of intestinal fatty acid binding protein (I-FABP) and traditional biomarkers in the early diagnosis of acute intestinal ischaemia of different causes.

METHODS

I-FABP, white blood cell (WBC) count, C-reactive protein, base deficit, lactate, lactate dehydrogenase, aspartate aminotransferase, creatine kinase and D-dimer were measured prospectively in consecutive patients suspected of having acute intestinal ischaemia. Biomarker levels were compared in patients with vascular and non-vascular ischaemia.

RESULTS

Two hundred and eight patients with a clinical suspicion of acute intestinal ischaemia were enrolled. Vascular intestinal ischaemia was diagnosed in 24 patients (11·5 per cent), non-vascular ischaemia in 62 (29·8 per cent) and non-ischaemic disease in 122 (58·7 per cent). The levels of most biomarkers (except WBC count and creatine kinase) were significantly higher in the vascular ischaemia group than in the other groups (P < 0·010). However, none of the biomarker levels differed between patients with non-vascular intestinal ischaemia and those with non-ischaemic disease. Receiver operating characteristic (ROC) curve analysis suggested that I-FABP was best at diagnosing vascular intestinal ischaemia (area under the curve 0·88).

CONCLUSION

Serum biomarkers may be useful in the diagnosis of vascular, but not non-vascular, intestinal ischaemia. Among them, I-FABP shows promise for detecting vascular ischaemia.

Modern treatment of acute mesenteric ischaemia

BACKGROUND

Diagnosis of acute mesenteric ischaemia in the early stages is now possible with modern computed tomography (CT), using intravenous contrast enhancement and imaging in the arterial and/or portal venous phase. The availability of CT around the clock means that more patients with acute mesenteric ischaemia may be treated with urgent intestinal revascularization.

METHODS

This was a review of modern treatment strategies for acute mesenteric ischaemia.

RESULTS

Endovascular therapy has become an important alternative, especially in patients with acute thrombotic superior mesenteric artery (SMA) occlusion, where the occlusive lesion can be recanalized either antegradely from the femoral or brachial artery, or retrogradely from an exposed SMA after laparotomy, and stented. Aspiration embolectomy, thrombolysis and open surgical embolectomy, followed by on-table angiography, are the treatment options for embolic SMA occlusion. Endovascular therapy may be an option in the few patients with mesenteric venous thrombosis who do not respond to anticoagulation therapy. Laparotomy is needed to evaluate the extent and severity of visceral organ ischaemia, which is treated according to the principles of damage control surgery.

CONCLUSION

Modern treatment of acute mesenteric ischaemia involves a specialized approach that considers surgical and, increasingly, endovascular options for best outcomes.

The diagnosis of acute mesenteric ischemia: A systematic review and meta-analysis

OBJECTIVES

Acute mesenteric ischemia is an infrequent cause of abdominal pain in emergency department (ED) patients; however, mortality for this condition is high. Rapid diagnosis and surgery are key to survival, but presenting signs are often vague or variable, and there is no pathognomonic laboratory screening test. A systematic review and meta-analysis of the available literature was performed to determine diagnostic test characteristics of patient symptoms, objective signs, laboratory studies, and diagnostic modalities to help rule in or out the diagnosis of acute mesenteric ischemia in the ED.

METHODS

In concordance with published guidelines for systematic reviews, the medical literature was searched for relevant articles. The Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2) for systematic reviews was used to evaluate the overall quality of the trials included. Summary estimates of diagnostic accuracy were computed by using a random-effects model to combine studies. Those studies without data to fully complete a two-by-two table were not included in the meta-analysis portion of the project.

RESULTS

The literature search identified 1,149 potentially relevant studies, of which 23 were included in the final analysis. The quality of the diagnostic studies was highly variable. A total of 1,970 patients were included in the combined population of all included studies. The prevalence of acute mesenteric ischemia ranged from 8% to 60%. There was a pooled sensitivity for l-lactate of 86% (95% confidence interval [CI] = 73% to 94%) and a pooled specificity of 44% (95% CI = 32% to 55%). There was a pooled sensitivity for D-dimer of 96% (95% CI = 89% to 99%) and a pooled specificity of 40% (95% CI = 33% to 47%). For computed tomography (CT), we found a pooled sensitivity of 94% (95% CI = 90% to 97%) and specificity of 95% (95% CI = 93% to 97%). The positive likelihood ratio (+LR) for a positive CT was 17.5 (95% CI = 5.99 to 51.29), and the negative likelihood ratio (-LR) was 0.09 (95% CI = 0.05 to 0.17). The pooled operative mortality rate for mesenteric ischemia was 47% (95% CI = 40% to 54%). Given these findings, the test threshold of 2.1% (below this pretest probability, do not test further) and a treatment threshold of 74% (above this pretest probability, proceed to surgical management) were calculated.

CONCLUSIONS

The quality of the overall literature base for mesenteric ischemia is varied. Signs, symptoms, and laboratory testing are insufficiently diagnostic for the condition. Only CT angiography had adequate accuracy to establish the diagnosis of acute mesenteric ischemia in lieu of laparotomy.