MAGNIFYING ENDOSCOPIC OBSERVATION OF THE UPPER GASTROINTESTINAL TRACT

Recent advances in technology enable us to obtain more detailed information during endoscopic procedures. Diagnosis of the pit pattern or microvascular architecture allow the earlier detection of neoplastic lesions in the gastrointestinal tract. These advances have led to the enhanced selection of appropriate treatments. Cancers that are discovered at an early stage can be treated by mucosal resection, whereas advanced cancers are treated with surgery. Recently, some groups have tried to acquire direct in vivo histological images of gastrointestinal mucosa (virtual histology or optical biopsy). Now optical coherence tomography (OCT), confocal laser endoscopy and endo‐cytoscopy systems enable this conception. However, none of these techniques has been proven, although some investigators have been able to use them to enhance cancer detection, and have reported the usefulness of these techniques. The present review assesses the strengths and weaknesses of these technologies, and describes the magnifying observations of the upper gastrointestinal tract using magnifying endoscopy equipment available on the market as well as newly developed endo‐cytoscopy systems. Published and unpublished data for this review were identified by searches of MEDLINE, Register of Cancer Trials: National Cancer Institute ( http://cancertrials.nci.nih.gov/ ) and references from relevant articles. We also contacted researchers. The authors’ own database of references was also used. The search items were as follows: magnifying endoscopy, endo‐cytoscopy system, confocal endoscopy, optical coherence tomography, contact endoscopy, esophageal cancer, Barrett’s esophagus, Barrett’s esophageal cancer, gastric cancer, colon cancer, chromoendoscopy, methylene blue etc.     

MICROVASCULAR PATTERNS OF ESOPHAGEAL MICRO SQUAMOUS CELL CARCINOMA ON MAGNIFYING ENDOSCOPY

Background: Recently, esophageal microcancers have been frequently diagnosed and are receiving increasing attention as initial findings of cancer. We examined whether the clinicopathological features and microvascular patterns of esophageal microcancers on magnifying endoscopy are useful for diagnosis. Methods: Magnifying endoscopy was performed to examine the histopathological features of 55 esophageal cancers measuring ≤10 mm in diameter (34 small cancers, 16 microcancers, and five supermicrocancers). Results: Although some lesions were detected only on iodine staining, most were detected on conventional endoscopic examination. Most small cancers and microcancers were m1 or m2; some were m3 or sm2. Supermicrocancers were dysplasia or m1 cancer. As for the microvascular pattern, most m1 and m2 cancers showed type 3 vessels, while most submucosal cancers showed type 4 vessels. Conclusions: Microvascular patterns on magnifying endoscopy are useful for the differential diagnosis of benign and malignant esophageal cancers and for estimating the depth of tumor invasion. The shape of small lesions is often altered considerably by biopsy. Residual tumor may persist unless the basal layer of the lesion is included in biopsy specimens, even in microcancers. Consequently, endoscopic mucosal resection, without biopsy, is being performed in increasing numbers of patients with lesions suspected to be cancer on the basis of their microvascular patterns.     

DIFFERENTIAL DIAGNOSIS OF GASTRIC LESIONS BY MAGNIFYING ENDOSCOPY

We performed magnifying endoscopy for patients with suspected gastric diseases. Among these patients, 67 patients with early gastric cancer and 31 benign gastric diseases were enrolled in this study. The patients with early gastric cancer included 46 differentiated tubular adenocarcinoma (33 mucosal cancer, 13 submucosal cancer) and 21 non‐differentiated tubular adenocarcinoma (12 mucosal cancer, 9 submucosal cancer). The benign gastric lesions included 23 gastric ulcer or gastric ulcer scars, three gastritis, and five gastric adenomas. Small regular patterns were observed; 39% in differentiated adenocarcinoma, 5% in undifferentiated adenocarcinoma, and 19% in benign gastric diseases. Irregular patterns were observed 37%, 52%, and 6%. Lack of visible structure was observed 18%, 90%, and 10%. Abnormal vessels were observed 26%, 81%, and 16%. Small regular patterns were observed significantly more frequently in differentiated adenocarcinoma than in undifferentiated adenocarcinoma (P < 0.001). Lack of visible structure and Irregular patterns were observed significantly more frequently in undifferentiated adenocarcinoma than in differentiated adenocarcinoma (P < 0.001). In order to spread this useful endoscopy widely easy recognition of abnormality, histological backbone, and further technical developments in hardware and software should be required.     

SURVEILLANCE BY MAGNIFYING ENDOSCOPY IN PATIENTS WITH ULCERATIVE COLITIS

Background: Patients with total or left‐sided ulcerative colitis (UC) for more than 10 years have an increased risk of colon cancer. We studied usefulness of magnifying chromoendoscopy for the surveillance of dysplasia and colitic cancer associated with UC. Methods: From April 2003 through February 2004, 39 patients who had total or left‐sided UC for at least 7 years were prospectively enrolled in an endoscopic surveillance program, including target biopsy. All patients were examined by chromoendoscopy and magnifying endoscopy. Sites showing abnormal mucosal surface patterns or pit patterns suggestive of dysplasia underwent biopsy. Results: Of the 39 patients, 26 had total UC and 13 left‐sided UC. The mean time elapsed since the onset of UC was 16.2 ± 5.9 years. Disease activity at examination was remission in 22 patients, mild in 15, and moderate in two. Dysplasia was diagnosed in two patients (three lesions), dysplastic changes were suspected in two (two lesions), and sporadic adenoma was diagnosed in four (five lesions). On endoscopic examination, dysplasia appeared as flat elevated lesions with types IIIl and IV pit patterns. Resected specimens showed low‐to‐high‐grade dysplasia. The four patients presenting with a type III to IV mucosal pit pattern during remission were evaluated as sporadic adenoma on pathological findings. Conclusions: A combination of chromoendoscopy and magnifying endoscopy is useful for the detection of dysplasia and colitic cancer in patients with UC.     

MAGNIFICATION ENDOSCOPY IN THE UPPER GI TRACT

Magnification endoscopy in conjunction with chromoendoscopy provides additional valuable and detailed information with respect to mucosal morphology. The most promising indications include the depiction and staging of squamous cell cancer of the esophagus, the potential to identify neoplasia within Barrett's esophagus, and the demarcation of early gastric cancer. However, the exact role of magnification endoscopy for routine clinical practice is not yet determined and is currently under investigation     

USEFULNESS OF DOUBLE BALLOON ENTEROSCOPY AND VIDEO CAPSULE ENDOSCOPY FOR THE DIAGNOSIS AND MANAGEMENT OF PRIMARY FOLLICULAR LYMPHOMA OF THE GASTROINTESTINAL TRACT IN ITS EARLY STAGES

Aim: The aim of this study is to evaluate the usefulness of double balloon enteroscopy (DBE) and video capsule endoscopy (VCE) in patients with primary follicular lymphoma (FL) of the gastrointestinal (GI) tract. Furthermore, we estimate the effectiveness of chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone) including rituximab for them. Methods: Thirteen consecutive patients who were diagnosed of having FL in the duodenum between July 2005 and September 2008 were studied. All patients were given the conventional staging examinations, including total enteroscopy using DBE and/or VCE procedures. Chemotherapy was performed after written informed consent. Response assessment was performed every 6‐12 months. The median follow‐up period was 30.2 months. Results: FL was diagnosed in each patient as low grade (grade 1, n = 7; 2, n = 6) and, in all but 4 patients, localized lymphoma (stage I, n = 8; II₁, n = 1; II₂, n = 4). DBE revealed multifocal lesions in the jejunum in 10 of the patients, and in the ileum in 6. VCE showed similar findings in the jejunum in the recent 2 patients. Eleven of 13 patients finally received chemotherapy, and all of them achieved complete regression. They showed no evidence of recurrence after that. Conclusion: Total examination of the small intestine using DBE should be performed before treatment to choose a suitable treatment procedure for primary FL of the GI tract. On the other hand, VCE is useful for screening and following the small intestine in the patients with it. Chemotherapy is effective to achieve complete regression of primary FL of the GI tract.     

CARDIOVASCULAR TOLERANCE IN UNSEDATED UPPER GASTROINTESTINAL ENDOSCOPY: PROSPECTIVE RANDOMIZED COMPARISON BETWEEN TRANSNASAL AND CONVENTIONAL ORAL PROCEDURES

Background: The utility of transnasal esophagogastroduodenoscopy (EGD) using ultrathin endoscopy has previously been described by analyzing subjective information and comparing it to conventional oral EGD. Limited information is available regarding the advantageous use of nasal EGD when assessed by reliable objective data. Methods: A total of 927 patients undergoing unsedated EGD between June 2004 and May 2005 were enrolled. We used a partially randomized patient‐centered study design in order to exclude a bias of the patient’s preference. Patients were divided into four groups. Patients who preferred oral or nasal EGD underwent endoscopy according to their preference (preferred group). Patients without preference were randomly assigned to oral and nasal EGD (randomized group). Pulse, blood pressure (BP) and peripheral blood oxygen saturation (SpO₂) were monitored during the procedure. Acceptability of EGD was also assessed by an acceptance score and the rate of willingness to repeat the same procedure. Results: Oral and nasal EGD were performed in 325 and 387 patients, respectively, in the preferred group, and 81 and 77 cases, respectively, in the randomized group. Nasal EGD was incomplete in 57 patients. Increases in BP were significantly lower in nasal EGD than in oral endoscopy in both the randomized and preferred groups, whereas no significant difference was found in the increment of pulse between the groups. Changes in SpO₂ were minimal in either procedure. Analyses of patient acceptability showed favorable evaluation of nasal EGD in both randomized and preferred groups. Conclusions: Nasal EGD appears to be less stressful to the cardiovascular system. Patient’s acceptability also supports its usefulness unless difficulties in transnasal insertion are encountered.     

A REVIEW OF CURRENT CLINICAL APPLICATIONS OF UPPER GASTROINTESTINAL ZOOM ENDOSCOPY

Current clinical applications of upper gastrointestinal (GI) zoom endoscopy were reviewed. The objective of upper GI zoom endoscopy has been the diagnosis of neoplastic lesions as well as the diagnosis of minute inflammatory mucosal change. The target organ and pathology of the neoplastic lesions have been squamous cell carcinoma in the oro‐ and hypo‐pharynx and in the esophagus; intestinal metaplasia, dysplasia, and adenocarcinoma in Barrett's esophagus; and adenocarcinoma in the stomach. For analyzing the magnified endoscopic findings, there were two different basic principles (mucosal microstructural change and subepithelial microvascular changes). Overall diagnostic accuracy for diagnosing a neoplastic lesion was above 80% throughout the upper GI tract. Although the diagnostic accuracy of the zoom endoscopy technique seems to be superior to that of the ordinary endoscopy technique alone, the continuous efforts to establish standardized guidelines and procedures are mandatory in order to lead to the routine use of upper GI zoom endoscopy in clinical practice.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR EARLY GASTRIC CANCER USING MAGNIFYING ENDOSCOPY WITH A COMBINATION OF NARROW BAND IMAGING AND ACETIC ACID INSTILLATION

Demarcation of early gastric cancers is sometimes unclear. Enhanced‐magnification endoscopy with acetic acid instillation and magnifying endoscopy with a narrow band imaging (NBI) system have been useful for recognition of demarcation of early gastric cancers. We report a patient with early gastric cancer who underwent a successful endoscopic submucosal dissection (ESD) by magnifying endoscopy with the combined use of NBI and acetic acid instillation. A 72‐year‐old man with early gastric cancer underwent ESD. Demarcation of the lesion was not clear, but magnifying endoscopy using the combination of NBI and acetic acid clearly revealed the demarcation. ESD was carried out after spots were marked circumferentially. We identified the positional relation between the demarcation and all markings. Resection of the lesion was on the outside of the markings. Histopathologically, the lesion was diagnosed as a well‐differentiated adenocarcinoma limited to the mucosa. The margins were carcinoma free. Magnifying endoscopy combining the use of NBI with acetic acid instillation is simple and helpful for identifying the demarcation of early gastric cancer. This method may be useful in increasing the rate of complete resection by ESD for early gastric cancer.     

RELATIONSHIP BETWEEN PULSE WAVE VELOCITY AND CIRCULATORY HEMODYNAMICS DURING UPPER GASTROINTESTINAL ENDOSCOPY

Background: Arterial stiffness has recently been proposed as a powerful independent predictor of cardiovascular disease. The aim of the present study was to establish the relationship between aortic stiffness and circulatory complications during gastrointestinal endoscopy using pulse wave velocity (PWV) as a parameter. Methods: We serially monitored standard 12‐lead ECGs, blood pressure, and percutaneous arterial oxygen saturation during gastrointestinal endoscopy, and performed a spectral analysis of heart rate variability and an analysis of QT dispersion. We also performed a logistic multivariate analysis of the severity of atherosclerosis and changes in the circulatory kinetics using PWV. Results: In the elderly group (older than 65 years), the rate of decrease in parasympathetic nervous activity and rate of change in blood pressure and QT dispersion were significantly larger than those in the non‐elderly group (younger than 65 years) (P < 0.05). However, a multivariate analysis showed that the relative risk for the grade of atherosclerosis was greater in an evaluation by PWV than by age. Conclusions: We conclude that the grade of atherosclerosis, as evaluated from PWV, is a stronger predictive factor for changes in circulatory kinetics during gastrointestinal endoscopy than age. PWV screening may facilitate the prevention of cardiac accidents during gastrointestinal endoscopy to some degree.     

CARDIOVASCULAR TOLERANCE IN UPPER GASTROINTESTINAL ENDOSCOPY USING AN ULTRATHIN SCOPE: PROSPECTIVE RANDOMIZED COMPARISON BETWEEN TRANSNASAL AND TRANSORAL PROCEDURES

Background: Transnasal esophagogastroduodenoscopy (EGD) has been suggested to be better tolerated by the cardiovascular system with a lower elevation of systolic blood pressure (BP) than oral EGD. However, limited information is available on the precise comparison of cardiovascular responses between the two endoscopic procedures using the same ultrathin scope. Methods: A prospective patient‐centered randomized study was performed to examine BP, pulse rate (P) and peripheral blood oxygen saturation (SpO₂) during nasal and oral EGD using the same ultrathin endoscope. The acceptability of EGD was also assessed using a visual analog scale. A total of 1147 patients were divided into four groups: patients who preferred oral or nasal EGD underwent endoscopy according to their preference (preferred group) and patients without preference were randomly assigned to oral and nasal EGD (randomized group). Results: The study design excluded a bias of the patient's preference. The randomized group involved 149 patients among whom 74 and 75 cases were assigned to the transnasal and oral EGD groups, respectively. The results in the randomized group confirmed a significantly lower elevation of BP in patients undergoing transnasal EGD than those undergoing oral EGD, while the increase in P was slightly smaller in patients undergoing the nasal procedure. Changes in SpO₂ were minimal in either procedure. Analyses of patient acceptability showed a favorable evaluation of nasal EGD. Conclusions: The present study confirmed less cardiovascular stress using nasal EGD than oral endoscopy when compared using the same ultrathin scope.     

MORPHOMETRY FOR MICROVESSELS IN EARLY GASTRIC CANCER BY NARROW BAND IMAGING‐EQUIPPED MAGNIFYING ENDOSCOPY

Background and Aim: Microvascular architecture is a variable characterizing early gastric cancer (EGC) against the background. The aims of the present study were to measure morphological variables of the microvessels and to compare the variables between EGC and the background. Methods: Narrow band imaging (NBI)‐equipped magnifying endoscopic pictures from 32 patients with EGC were used. The endoscopic pictures were taken under maximal magnification and processed for the microvessels in an in‐focus area after correction of image distortion. The segmented microvessels were numbered for microvessel density (counts/mm²) and vascular bed area (% ratio of vascular bed against the region of interest). The microvessels were further processed for a set of skeletonized pixels to count the characteristic points, including end‐points, crossing points, branching points and connecting points. Results: Microvessels in cancer were found to have a significantly larger connected point number (20.5 ± 6.1, P = 0.0002) than those in the background (17.4 ± 3.9). Numbers of the end‐points and branching points were found to be significantly larger in cancer than in the background (end‐points 3.6 ± 0.7 for cancer vs 3.3 ± 0.4 for background, P = 0.0005; branching points 0.8 ± 0.4 for cancer vs 0.7 ± 0.2 for background, P = 0.0014). However, microvessel density, vascular bed area and mean diameter did not significantly differ between cancer and the background. Conclusion: This finding can be considered to reflect the reported observation of an irregular vascular pattern in gastric cancer. This method may provide a means for microvessel morphometry, regardless of the organ studied.     

肝硬变上消化道大出血病因的内镜诊断

肝硬变上消化道大出血患者６２例，出血后６小时～１周内行胃镜检查及硬化剂治疗。检查证实无食管胃底静脉曲张２例；胃及十二指肠球部明显糜烂１４例（２２．６％），胃和十二指肠球部溃疡６例（９．７％）。９例（１４．５％）为非静脉曲张性出血，７例（１１．３％）为双因素性出血，表明将肝硬变上消化道大出血一概推断为食管静脉曲张破裂出血是片面的。作者强调早期内镜检查和治疗的重要性。     

CONTACT ULTRA‐HIGH MAGNIFYING ENDOSCOPY CAN DIFFERENTIATE SQUAMOUS CELL CARCINOMA FROM NON‐CANCEROUS SQUAMOUS CELLS IN THE ESOPHAGUS: TWO CASES OF SUPERFICIAL ESOPHAGEAL CARCINOMA

Endocytoscopy, a type of contact ultra‐high magnifying endoscopy, enables in vivo observation of cells in the gastrointestinal tract. To test its clinical relevance, endocytoscopy was conducted on ex vivo specimens from two cases of superficial esophageal carcinoma that were resected by endoscopic mucosal resection (EMR). Using a catheter‐type system with ×450 magnification, endocytoscopic observation was performed on small areas of cancerous and non‐cancerous squamous cells, which were subsequently retrieved for pathological examination on horizontal sections. In both cases, endocytoscopy identified non‐cancerous areas as cells with sparsely distributed round nuclei and a low nucleus‐cytoplasm (NC) ratio, which correlated well with histological sections. Similarly, the endocytoscopy correlated well with histological sections of cancerous areas and identified cells with densely distributed irregular nuclei with a high NC ratio. In conclusion, the high correlation between histological and endocytoscopic identification of cancerous and non‐cancerous lesions may enable endocytoscopic diagnosis that is of comparable accuracy to the current pathological methodology. A prospective in vivo study is required to confirm the evidence.     

RARE CAUSE OF OBSCURE GASTROINTESTINAL BLEEDING DUE TO PYOGENIC GRANULOMA IN THE ILEUM DETECTED BY CAPSULE ENDOSCOPY AND TREATED WITH DOUBLE BALLOON ENDOSCOPY

Pyogenic granuloma is a lobular capillary hemangioma that occurs mostly on the skin, and occasionally on the mucosal surface of the oral cavity, but very rarely in the gastrointestinal tract. We report the case of a 63‐year‐old woman who suffered from palpitations, and iron deficiency anemia for 5 years. Esophagogastroduodenoscopy and colonoscopy could not reveal significant bleeding focus. She had not received medical treatment except for oral iron. Capsule endoscopy revealed a bleeding focus in the small intestine. Afterwards, we carried out double balloon endoscopy to treat the lesion. We found a subpedunculated polyp in the small intestine at 100 cm away from ileocecal valve by double balloon endoscopy and resected it endoscopically. The histological features of the polyp were consistent with pyogenic granuloma. Anemia had improved gradually without giving oral iron after polypectomy.     

ANGIOGENESIS IN SUPERFICIAL ESOPHAGEAL SQUAMOUS CELL CARCINOMA: MAGNIFYING ENDOSCOPIC OBSERVATION AND MOLECULAR ANALYSIS

Observations of esophageal squamous cell carcinoma using magnifying endoscopy have now been carried out extensively and, as a result, it has become clear that the morphology of the microvessels evident at the tumor surface reflects the depth of tumor invasion. In M1 and M2 cancer, the surface microvasculature reveals dilation and elongation of the intrapapillary capillary loops (IPCL). However, at this stage, some immature capillaries resembling IPCL also arise inside the tumor and, therefore, the view of the microvasculature should be described as one showing ‘intermixing of modified IPCL and IPCL‐like immature capillaries (IPCL‐like abnormal capillary)’. As cancer invades into the muscularis mucosa (M3 or deeper), an obviously dilated and irregularly branched tumor‐specific vasculature, more accurately described as ‘neovasculature’, can be observed. From our magnifying endoscopy observations and studies of the molecular profile of early esophageal cancer, we conclude that two major angiogenic steps exist in precancerous and M3 lesions in the early phase of cancer progression. In addition, it is now possible to study cell morphology using an endocytoscope with a much higher magnification (×400–×1000) than magnifying endoscopes currently on the market. The histology revealed in this way may reduce the need for conventional biopsy histology in the future.     

EARLY GASTRIC CANCER: PROPOSAL FOR A NEW DIAGNOSTIC SYSTEM BASED ON MICROVASCULAR ARCHITECTURE AS VISUALIZED BY MAGNIFIED ENDOSCOPY

We have developed a magnified endoscopic technique for observing the microvascular architecture within the gastric mucosa in units as small as capillary and we have reported the characteristic findings of the microvascular architecture in both normal gastric mucosa and early gastric cancer. The findings in the normal stomach were different depending on the section of the stomach. The body mucosa demonatrated a regular honeycomb‐like subepithelial capillary network pattern with a collecting venule, while the antral mucosa demonstrated a regular coil‐shaped subepithelial capillary network pattern. The magnified endoscopic findings of early gastric carcinoma were different depending on the types of histological differentiation. The characteristic findings of differentiated carcinoma were (1) the presence of a demarcation line; (2) the disappearance of the regular subepithelial capillary network pattern; and (3) the presence of an irregular microvascular pattern. The findings of undifferentiated carcinoma showed only a reduction in or else the complete disappearance of the regular subepithelial capillary network pattern. In clinical practice, the magnified endoscopic findings of differentiated carcinoma are useful both for determining the margin of early gastric cancer and for making a differential diagnosis between gastritis and gastric cancer in the case of flat reddened lesions. The microvascular architecture as visualized by magnified endoscopy could be a new diagnostic system for the endoscopic diagnosis of early gastric cancer.     

ECHINOSTOMA HORTENSE ASADA INFECTION IN THE DUODENUM: INCIDENTAL FINDINGS DURING ROUTINE GASTROINTESTINAL ENDOSCOPY

We report herein a case of Echinostoma hortense Asada infection, which is known to derive from eating fresh frogs or loaches, which was discovered during routine gastrointestinal endoscopy. To our knowledge, this is the first report in Japan of E. hortense Asada infection observed by means of magnifying endoscopy.     

CARDIOVASCULAR TOLERANCE AND AUTONOMIC NERVOUS RESPONSES IN UNSEDATED UPPER GASTROINTESTINAL SMALL‐CALIBER ENDOSCOPY: A COMPARISON BETWEEN TRANSNASAL AND PERORAL PROCEDURES WITH NEWLY DEVELOPED MOUTHPIECE

Background: Transnasal esophagogastroduodenoscopy (EGD) with small‐caliber endoscopy appears to be less stressful to the cardiovascular system and has good patient tolerance. ENDO LEADER, a newly developed mouthpiece for peroral EGD with small‐caliber endoscopy, is expected to reduce patient stress. We compared the patient acceptance, cardiovascular tolerance and autonomic nervous responses between transnasal EGD and peroral EGD with ENDO LEADER. Patients and Methods: A total of 130 patients (transnasal group, 77; peroral group, 53) were enrolled. Pulse rate (P), blood pressure (BP), and peripheral blood oxygen saturation (SpO₂) were monitored. Acceptance of EGD was also assessed. Autonomic nervous responses were evaluated through analysis of heart rate variability using amplitude of the high‐frequency component (HF) and low‐frequency‐to‐high‐frequency power ratio (LF/HF) as indices of cardiac vagal activity and sympathetic activity, respectively. Results: Analysis of patient acceptance showed no differences between the two groups, except with regard to nasal pain. Increases in BP and P between before and during EGD examination were significantly higher in the peroral group. Although throat pain and overall tolerance scores were significantly correlated with ΔBP and ΔP, no correlations with nasal pain score were noted. Heart rate variability analysis revealed that heart rate increased significantly in the peroral group, but there were no differences in ΔHF or ΔLF/HF between the two groups. Conclusions: Patient acceptance was not significantly different between the transnasal and peroral with ENDO LEADER groups; however, transnasal EGD appears to be less stressful to the sympathetic nervous system, leading to smaller elevations in BP, P and heart rate.     

NO EVIDENCE FOR PATIENT‐TO‐PATIENT TRANSMISSION OF HEPATITIS C VIRUS DURING UPPER GASTROINTESTINAL ENDOSCOPY: MOLECULAR STUDIES ON THREE ACUTE HEPATITIS C PATIENTS

Background: The risk of patient‐to‐patient transmission of hepatitis C virus (HCV) during endoscopy remains controversial. Using molecular approaches, we examined the possibility of patient‐to‐patient transmission of HCV in three patients who developed acute hepatitis C 1–6 months after examination by upper gastrointestinal endoscopy (UGIE) in a hospital endoscopy unit in Japan. Methods: For the source of HCV infection, we used frozen sera obtained from potential candidates who underwent UGIE earlier than three index patients on the same days in the same unit. HCV genotype was determined by multiplex polymerase chain reaction (PCR) with genotype‐specific primers. The 1087‐nucleotide (nt) sequence of the NS5B region of the HCV genome was compared between index patients and their HCV‐viremic candidates. Results: The three index patients were exclusively infected with HCV of genotype 1b. Among a total of 60 candidate patients who underwent UGIE earlier than the index patients, 14 were positive for anti‐HCV, of whom 12 had detectable HCV‐RNA (1b, n = 9; 2a, n = 1; 2b, n = 2) on sera collected during each UGIE. Shared identity within the 1087‐nt NS5B sequence was less than 95.0% between index patients and HCV/1b‐infected candidates (n = 3, 1 and 5, respectively). None of the remaining 46 candidates who were negative for anti‐HCV at UGIE examination tested positive for HCV‐RNA, nor seroconverted to anti‐HCV on their sera, which most likely excludes the possibility of HCV viremia despite the anti‐HCV‐negative serology at UGIE examination. Conclusion: The present study suggests that patient‐to‐patient transmission of HCV during UGIE is infrequent.