The most noticeable finding in this study is the higher prevalence of GAVE (56%) than reported in previous studies (13%) [14, 15]. We reported that this percentage is probably due to the high prevalence of liver cirrhosis in Egypt. Other factors can contribute in the pathogenesis of GAVE and should be investigated like the role of metabolic syndrome [16]. Another finding was the presence of a type of GAVE that appeared as one or two red spots in the antrum. This form was detected by VIST view only and was confirmed by histopathology. It can be an early stage of development of diffuse GAVE or it may be a new subtype that was not covered in literature. According to Thomas et al., he has described only three phenotypes for GAVE: linear, diffuse, and nodular [5]. Thus, a new term could be introduced “focal GAVE”; this may be added to GAVE classification. This highlights the superiority of VIST over WLE in the detection of focal GAVE.
The efficacy of virtual chromoendoscopy has been proven in the diagnosis of GAVE over WLE without the need for invasive intervention in taking biopsy. VIST has succeeded in the diagnosis of 23/28 cases of GAVE. While WLE diagnosed only 2/28 of the cases. Our results were in consistence with Chang et al. who demonstrated the accuracy of NBI in the diagnosis of GAVE [12]. As PHG and GAVE are two different pathologies with different management, this could accelerate the diagnosis of GAVE and early management of bleeding.
The sensitivity of VIST was 82.1% in the diagnosis of GAVE versus WLE (7.1%). Which made VIST a good screening tool for the detection of GAVE among the patients with PHG. WLE has a specificity that reached 95.5%, but it only detected the cases of the typical endoscopic image, which were two cases only. While the specificity of VIST was lower (59.1%), VIST has succeeded to detect 12/13 of the focal GAVE cases (92.3%) and 11/15 of the diffuse GAVE cases (73.3%). The specificity decreased due to the presence of false positive cases in the diagnosis of diffuse form, mostly due to the presence of other etiologies as H Pylori, dysplasia, and one case of PHG. VIST had sensitivity and specificity that reached 92.3% and 92.8% respectively for diagnosis of the new subtype “Focal GAVE” with Kappa measure of agreement (0.85). Therefore, VIST can be a good test for the detection of focal GAVE. In the literature about the new endoscopic technology, GAVE was not widely covered. NBI, flexible spectral imaging color enhancement (FICE), and I-scan showed superiority over WLE in differentiating GAVE from PHG, but their number of patients was relatively smaller than in this study [12, 17, 18]. In addition, this study is considered the first to use VIST technology for the detection of GAVE.
The role of immunohistochemistry was complementary to histopathology. The diagnosis of GAVE depends on the presence of spindle cell proliferation, fibrohyalinosis, and most characteristically the presence of fibrin thrombi. The use of CD61 was important to identify subtle fibrin thrombi, not detected by H & E stain and thus to increase the detection of GAVE. It only reflects that GAVE can be present and not be able to be detected with regular histopathological examination. In the study, CD61 detected only one patient of the suspected GAVE by VIST in addition to the total diagnosed with H&E. Westerhoff et al detected more suspected cases of GAVE by using CD61, but he used conventional endoscopy to diagnose GAVE [13].
In conclusion, the efficacy of VIST a new technology derived from Narrow Band with a lower cost has been demonstrated in the diagnosis of GAVE in cirrhotic patients without the need for biopsy. Non-invasive vascular enhancement screening tool is mandatory, especially in cirrhotic patients with high bleeding tendency. VIST can be more reliable than WLE in the diagnosis of GAVE, and it could be used as a screening tool for the detection of GAVE, especially the focal form. Unfortunately, due to COVID 19 pandemic, the number of patients was limited. Larger or multicentric studies are needed in the future to assess its accuracy.