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Kiesslich R, Goetz M, Lammersdorf K, et al. Chromoscopy‐guided endomicroscopy increases the diagnostic yield of intraepithelial neoplasia in ulcerative colitis. Gastroenterol 2007;132:874–82.
Dye‐spraying and new endoscope technology has ended the era of random multiple biopsies in colonoscopy surveillance in ulcerative colitis. It has already been shown that chromoscopy unmasks significant lesions in flat mucosa and increases the number of neoplasia detected. Magnification endoscopy, narrow‐band imaging and confocal laser endomicroscopy offer the possibility of in vivo lesion recognition, to increase the accuracy of distinguishing neoplastic from non‐neoplastic lesions without biopsy.
Kiesslich et al randomised 161 long‐term patients with ulcerative colitis to undergo either conventional colonoscopy (with quadrantic biopsies every 10 cm) or chromoscopy with endomicroscopy. In this latter group, patients received intravenous fluorescein to allow confocal laser endomicroscopy using a Pentax instrument. On withdrawal, 30 cm segments of colon were sprayed with 0.1% methylene blue and excess dye was removed by suction. Identified lesions were examined by endomicroscopy (not interfered with by dye spraying). Lesions were then graded by crypt or vessel architecture as normal, regenerative or neoplastic. Lesions were also scored for severity of inflammation. Biopsies were then taken from all lesions.
Eight patients were excluded for poor bowel preparation and only 25% of patients had pancolitis (significantly more in the conventional colonoscopy group). However, significantly more intraepithelial neoplasias were identified in the chromoscopy group (19/11 patients), than in the control group (4/4 patients). No cancers were found; 16/19 neoplasias in the chromoscopy group were flat and 7/19 were high‐grade (2/4 flat and 1/4 high‐grade in the control group). In 80 patients having chromoscopy, 312 targeted biopsies were taken. Of these, 62 had endomicroscopy evidence of intraepithelial neoplasia. The technique had a positive predictive value of 90% and negative predictive value of 99%.
In conclusion, chromoscopy with endomicroscopy resulted in a five‐fold increase in neoplasia detection, and in theory this could be achieved with a tenth of the number of biopsies. Many issues remain of course! The techniques only work well in non‐inflamed mucosa. How does confocal laser microscopy compare with narrow‐band imaging or simple magnification endoscopy? What are the training implications for endoscopists if these techniques are to be widely adopted? Do we want to move histological examination into the endoscopy room? Further work is needed but, now we can see more clearly, the age of random biopsies is past.
Jung B, Pahlman L, Nystrom P‐O, et al for the Mechanical Bowel Preparation Study Group. Multicentre randomized clinical trial of mechanical bowel preparation in elective colonic resection. Br J Surgery 2007;94:689–95.
Preoperative “clearing out” of the colon using osmotic and stimulant laxatives, known as mechanical bowel preparation (MBP), has long been regarded as one of the most important factors for safe elective colorectal surgery. However, since the 1990s a number of reports have questioned the benefits of MBP and four meta‐analyses concluded that MBP did not confer any advantage as far as anastomotic leak rate or other adverse events were concerned. Nevertheless, all these existing data have failed to change many surgeons' attitudes towards the use of MBP. The Mechanical Bowel Preparation Study Group has directly addressed this issue with a large, multicentre, randomised trial. A total of 1343 patients undergoing open colonic resections were evaluated, 686 randomised to MBP and 657 to no MBP. There were no significant differences in overall complications between the two groups: cardiovascular complications occurred in 5.1% and 4.6%; general infectious complications in 7.9% and 6.8%; and surgical‐site complications in 15.1% and 16.1%, respectively. At least one complication was recorded in 24.5% of patients who had MBP and 23.7% in those who did not.
Despite these clear findings and the authors' conclusion that MBP can be omitted before elective colonic resections, a number of issues remain unanswered. What of rectal resections and those resections requiring proximal faecal diversion with loop ileostomy? Furthermore, MBP prior to laparoscopic colonic surgery may be preferred as manipulation of a loaded colon with laparoscopic instruments can be difficult. On the other hand, small bowel dilatation following preparation can obscure clear views of the operative field. Although there are some exceptions, surgical attitudes seem destined to remain unchanged with regard to MBP until these issues are also addressed with randomised trials. However, the authors of this trial are to be congratulated.
Vizzutti F, Arena U, Romanelli RG, et al. Liver stiffness measurement predicts severe portal hypertension in patients with HCV‐related cirrhosis. Hepatology 2007;45:1290–7.
Transient elastography represents a novel ultrasound‐based technology wherein a vibration is transmitted to the liver, inducing an elastic shear wave that propagates through the liver tissue. Pulse‐echo ultrasound permits measurement of wave velocity expressed in kilopascals, which directly correspond to the liver stiffness. As the stiffness is sampled from 1×2 cm of liver it may be a better representation than the average liver biopsy sample. Hence, liver stiffness measurement is rapidly gaining popularity as a technology that may complement or even substitute liver biopsy, especially in the assessment of the degree of liver fibrosis.
Vizzutti et al have investigated the role of transient elastography in predicting the severity of portal hypertension, which is to an extent a function of liver fibrosis. Measurement of hepatic venous pressure gradient (HVPG) has remained the gold standard to detect and define portal hypertension and the best predictor of clinically relevant complications. Despite standing the test of time, HVPG hasn't been used widely because it involves a transjugular approach. Vizzutti et al compared the liver stiffness measurements with HVPG in 61 consecutive patients with hepatitis C related liver disease and found a strong relationship between the two measurements overall (r = 0.81, p<0.0001). Liver stiffness measurement cut‐off values of 13.6 kPa and 17.6 kPa predicted HVPG values of 10 and 12 mm Hg, with a sensitivity of 97% and 94%, respectively.
The findings of this study will widen the potential clinical application of transient elastography beyond its increasing use to detect and quantify liver fibrosis. If the findings of the current study are reproduced, it may turn out to be the most valid indication for transient elastography. However, Vizzutti et al report a suboptimal correlation of liver stiffness measurements with the HVPG values >10 mm Hg (r2 = 0.35). Therefore, transient elastography may not be a reliable predictor of a haemodynamic response to pharmacological interventions yet.