Acute mesenteric ischemia (AMI) is a vascular emergency caused by an interruption in blood flow to the small intestine, leading to cellular damage, intestinal necrosis, and death if untreated (24). The most common etiologies of AMI include in situ thrombosis, which has been reported in approximately 60%, embolism from atrial fibrillation in 30%, and non-occlusive mesenteric ischemia in 10% of patients (25). The overall incidence is low, accounting for 0.09 to 0.2% of all acute admission to emergency departments and representing an uncommon cause of abdominal pain (26, 27). Prompt diagnosis and intervention are essential to reduce mortality. However, despite constant improvements in diagnostic, interventional and surgical techniques and advances in radiologic modalities, AMI remains a life-threatening emergency with high mortality rates reported between 50 and 70% (28–30). In our study, the mortality rate was found as 55%, consistent with the literature. The incidence of AMI significantly increases with age. In a study by Yilmaz et al., the mean age of the patients with AMI was found as 67.62 years (31). In a study by Yildirim et al., the mean age of the patients was found as 67.5 (32). In another study by Otto et al. investigating prognostic factors for mortality in patients with AMI, the median age of the patients was found as 71 years (33). In our study, the mean age of all patients was found as 73.14 ± 10.37 years. Our finding was similar to the ages reported in previous studies.
The diagnosis of acute mesenteric ischemia can be established upon clinical suspicion, CT and CT angiography examinations in addition to laboratory investigations. This has prompted researchers to seek novel diagnostic and prognostic biomarkers for the management of AMI. In the present study, we compared pre- and postoperative fibrinogen, albumin, FAR ratio, hemoglobin, CRP, WBC, neutrophil, preoperative lymphocyte, ALT, AST and PLT, and postoperative D-dimer values between the survivor and non-survivor patients with AMI.
Fibrinogen is an acute phase soluble plasma glycoprotein, synthesized primarily in the liver and converted by thrombin into fibrin during blood coagulation. It has been studied in several diseases, including chronic obstructive pulmonary disease (COPD) (34), periprosthetic joint infection (35), the severity of COVID-19 (36), non-cystic fibrosis bronchiectasis (37) and lung cancer (38). In a case series by Al Mahruqi et al., fibrinogen was reported to be elevated in COVID-19 patients complicated with AMI (39). In a study by Cakmak et al., high levels of fibrinogen were reported to predict mortality in AMI (40). Likewise, in our study, both pre- and postoperative fibrinogen levels were statistically significantly higher in the non-survivor compared to the survivor patients with AMI (p < 0.001).
Historically, albumin has been widely used by physicians as a biomarker (41). Serum levels of albumin are significantly depressed as a result of inflammation through decreased synthesis and increased catabolism (42). In a study by Ozdemir et al. investigating mortality in AMI, neutrophil, RDW, lactate, D-dimer, Fibrinogen, and CK-MB levels, furthermore, albumin levels were defined as significantly elevated in the survivor group (40). Similarly, in our study, both pre- and postoperative albumin levels were significantly higher in the survivor group compared to the non-survivor group (p = 0.059, p < 0.001; respectively).
The Fibrinogen/Albumin Ratio (FAR) is increasingly considered a potential biomarker for predicting prognosis in various diseases (43). In a study by Cicekli et al., it was reported that FAR levels might be useful in predicting mortality risk in COVID-19 patients (44). In a study by Afsin et al., the FAR ratio at admission was associated with mortality in patients infected with SARS-CoV-2 in the ICU (45). In the present study, both pre- and postoperative FAR ratios were statistically significantly higher in the non-survivors compared to the survivors (both, p < 0.001). In addition, changes in the FAR ratio between pre- and postoperative periods were again significantly higher in the non-survivor group (p < 0.001). While postoperative FAR decreased in the survivor group, this rate increased postoperatively in the non-survivor group. In the logistic regression analysis, postoperative FAR value affected survival (B = 0.043 p < 0.001), while preoperative FAR did not affect (p = 0.671). These results suggested that the FAR ratio may have a prognostic value in predicting the prognosis of AMI. There was no study in the literature to compare FAR values in patients with AMI.
Several promising biomarkers have been reported for predicting the prognosis of AMI, including Intestinal fatty acid binding protein (I-FABP), a-glutathione S-transferase (a-GST), D-dimer, L- and D-lactate, citrulline, ischemia modified albumin and procalcitonin (PCT) (9). In a study by Destek et al., it was reported that the CRP level could be used effectively in the preoperative period to diagnose AMI and to determine its subtype and clinical course. However, L-lactate, D-dimer, leukocyte and neutrophil-to-lymphocyte (NLR) are markers that have no predictive value in the diagnosis of all AMI subtypes (10). In another study by Otto et al., it was reported that serum lactate appears to be of primary clinical importance as the risk of fatal outcome increases significantly with higher lactate values in AMI (33).
In our study, preoperative hemoglobin value was significantly higher in the survivor group, while postoperative CRP and D-dimer, and preoperative WBC and neutrophil count were significantly higher in the non-survivor group.
Study Limitations
The major limitation of this study is the relatively small number of patients. In addition, a cut-off value, sensitivity and specificity of FAR in predicting mortality in AMI patients could be studied. Furthermore, we could not compare our findings exactly as there is no similar study in the literature. Being conducted in two separate centres is a strength of this study.