Post-polypectomy bleeding and thromboembolism risks associated with warfarin vs direct oral anticoagulants

AIM To verify the validity of the endoscopy guidelines for patients taking warfarin or direct oral anticoagulants(DOAC).METHODS We collected data from 218 patients receiving oral anticoagulants(73 DOAC users, 145 warfarin users) and 218 patients not receiving any antithrombotics(age-and sexmatched controls) who underwent polypectomy.(1) We evaluated post-polypectomy bleeding(PPB) risk in patients receiving warfarin or DOAC compared with controls;(2) we assessed the risks of PPB and thromboembolism between three AC management methods: Discontinuing AC with heparin bridge(HPB)(endoscopy guideline recommendation), continuing AC, and discontinuing AC without HPB.RESULTS PPB rate was significantly higher in warfarin users and DOAC users compared with controls(13.7% and 13.7% vs 0.9%, P 0.001), but was not significantly different between rivaroxaban(13.2%), dabigatran(11.1%), and apixaban(13.3%) users. Two thromboembolic events occurred in warfarin users, but none in DOAC users. Compared with the continuing anticoagulant group, the discontinuing anticoagulant with HPB group(guideline recommendation) had a higher PPB rate(10.8% vs 19.6%, P = 0.087). These findings were significantly evident in warfarin but not DOAC users. One thrombotic event occurred in the discontinuing anticoagulant with HPB group and the discontinuing anticoagulant without HPB group; none occurred in the continuing anticoagulant group.CONCLUSION PPB risk was similar between patients taking warfarin and DOAC. Thromboembolism was observed in warfarin users only. The guideline recommendations for HPB should be re-considered.     

Postpolypectomy lower gastrointestinal bleeding: potential role of aspirin

INTRODUCTION: Limited data exist on the role of aspirin in increasing the risk of clinically significant postpolypectomy bleeding (PPB), which is defined as lower gastrointestinal (GI) hemorrhage following colonoscopic polyp removal requiring transfusion, hospitalization, endoscopic intervention, angiography, or surgery. OBJECTIVES: To determine if aspirin use prior to colonoscopy increases the risk of clinically significant PPB. METHODS: A case-control study of patients with clinically significant PPB at Mayo Clinic Scottsdale and Rochester was performed. Information collected included age, gender, recent use of aspirin or NSAIDs (within three days of colonoscopy), polyp characteristics, and polypectomy technique. The control group consisted of patients matched for age (+/-3 yr), gender, and cardiovascular morbidity who had undergone polypectomy without any complications. The populations were compared to determine the odds ratio (OR) of PPB with aspirin use. RESULTS: During the study period, 20,636 patients underwent colonoscopy with polypectomy at the two institutions and 101 patients presented with clinically significant PPB. Twenty patients were excluded from analysis because of prior anticoagulant use. The remaining 81 patients were matched to 81 patients who had undergone colonoscopy without complications. The two groups were comparable in terms of polyp size (97%< or = 10 mm, bleeding group; 95%< or = 10 mm, control group). Aspirin use prior to polypectomy was 40% in the bleeding group and 33% in the control group (OR 1.41; 95% C.I. 0.68 to 3.04). CONCLUSION: Postpolypectomy bleeding is an uncommon but important complication of endoscopic polypectomy. There was no statistically relevant difference in prior aspirin use before polypectomy in the bleeding group and the matched controls.     

Management of Anticoagulants and Antiplatelet Agents During Colonoscopy

Colonoscopy frequently is performed for patients who are taking aspirin, nonsteroidal anti-inflammatory drugs, antiplatelet agents, and other anticoagulants. These colonoscopies often involve polypectomy, which can be complicated by bleeding. The risks of precipitating thromboembolic complications if anticoagulants are stopped must be weighed against the risk of postpolypectomy bleeding if these agents are continued. This article systematically reviews the management of anticoagulation during elective and emergency colonoscopy. For patients undergoing colonoscopic polypectomy, the overall risk of postpolypectomy bleeding is <0.5%. Risk factors for postpolypectomy bleeding include large polyp size and anticoagulant use, especially warfarin and thienopyridines. For patients who do not stop aspirin or other nonsteroidal anti-inflammatory drugs prior to colonoscopy, the rate of postpolypectomy bleeding is not significantly different from that for patients who do not take those medications. For patients who continue thienopyridines and undergo polypectomy, the risk of delayed postpolypectomy bleeding is approximately 2.4%. Even for patients who interrupt warfarin, the risk of postpolypectomy bleeding is increased. The direct oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) have a rapid onset and offset of action, and periprocedural bridging generally is not necessary. For the thienopyridines, warfarin, and the direct oral anticoagulants, the decision to interrupt or continue these agents for endoscopy will involve considerable exercise of clinical judgment.     

Incidence and risk factors of delayed postpolypectomy bleeding in patients with chronic liver disease

Objective Hepatologists and colonoscopists often hesitate to perform a colonoscopic polypectomy in patients with chronic liver disease (CLD), especially those with cirrhosis, because of the risk of postpolypectomy bleeding (PPB). We aimed to investigate the incidence and risk factors of delayed PPB after a colonoscopic polypectomy in patients with CLD. Materials and methods In total, 152 patients with CLD who underwent colonoscopic polypectomy from December 2005 to December 2012 were retrospectively reviewed. Results Cirrhosis was identified in 80 (52.6%) patients. During the study period, 442 polyps were removed and delayed PPB developed in 14 (9.2%) patients. The incidence of delayed PPB was significantly higher in patients with cirrhosis than in those without the disease (13.8% [n?=?11] vs. 4.2% [n?=?3], p?=?0.041). The polyp size (odds ratio, 1.087; 95% confidence interval, 1.009–1.172) and cirrhosis (odds ratio, 8.535; 95% confidence interval, 2.417–30.140) were independent risk factors for delayed PPB. In patients with cirrhosis, the optimal cut-off size to identify high-risk polyps for delayed PPB was 10 mm (area under the receiver operating characteristics curve, 0.737; sensitivity, 52%; specificity, 88%). Conclusion Caution is needed when colonoscopic polypectomy is planned in patients with CLD who have larger polyps and cirrhosis.     

Risk factors for postoperative bleeding after gastric endoscopic submucosal dissection in patients under antithrombotics

AIM: To evaluate the risk factors for postoperative bleeding after gastric endoscopic submucosal dissection(ESD) based on the latest guidelines.METHODS: A total of 262 gastric neoplasms were treated by ESD at our center during a 2-year period from October 2012. We analyzed the data of these cases retrospectively to identify the risk factors for postESD bleeding.RESULTS: Of the 48(18.3%) cases on antithrombotic treatment, 10 were still receiving antiplatelet drugs perioperatively, 13 were on heparin replacement after oral anticoagulant withdrawal, and the antithrombotic therapy was discontinued perioperatively in 25 cases. Postoperative bleeding occurred in 23 cases(8.8%). The postoperative bleeding rate in the heparin replacement group was 61.5%, significantly higher than that in the non-antithrombotic therapy group(6.1%). Univariate analysis identified history of antithrombotic drug use, heparin replacement, hemodialysis, cardiovascular disease, diabetes mellitus, elevated prothrombin timeinternational normalized ratio, and low hemoglobin level on admission as risk factors for post ESD bleeding. Multivariate analysis identified only heparin replacement(OR = 13.7, 95%CI: 1.2-151.3, P = 0.0329) as a significant risk factor for post-ESD bleeding.CONCLUSION: Continued administration of antiplatelet agents, based on the guidelines, was not a risk factor for postoperative bleeding after gastric ESD; however, heparin replacement, which is recommended after withdrawal of oral anticoagulants, was identified as a significant risk factor.     

Management of gastrointestinal bleeding induced by gastrointestinal endoscopy

Therapeutic gastrointestinal endoscopy has a much greater risk of inducing gastrointestinal hemorrhage than diagnostic endoscopy. For example, colonoscopic polypectomy has a risk of approximately 1.6% of inducing bleeding, compared with a risk of approximately 0.02% for diagnostic colonoscopy. Higher-risk procedures include colonoscopic polypectomy, endoscopic biliary sphincterotomy, endoscopic dilatation, endoscopic variceal therapy, percutaneous endoscopic gastrostomy, and endoscopic sharp foreign body retrieval. The risk of inducing hemorrhage is decreased by meticulous endoscopic technique. Hemorrhage from endoscopy may be immediate or delayed. Immediate hemorrhage should be immediately treated by endoscopic hemostatic therapy, including injection therapy, thermocoagulation, or electrocoagulation. Delayed hemorrhage generally requires repeat endoscopy for diagnosis and for therapy, using the same hemostatic techniques.     

Management of anticoagulants before and after endoscopy.

The risk of procedure-related bleeding while taking anticoagulants needs to be weighed against the risk of thromboembolism from discontinuing these drugs. It is not necessary to adjust anticoagulation for low-risk procedures, such as upper endoscopy with biopsy, colonoscopy with biopsy or endoscopic retrograde cholangiopancreatography with stent insertion (but without sphincterotomy). Procedures that incur a high risk of bleeding include polypectomy, endoscopic sphincterotomy, laser therapy, mucosal ablation and treatment of varices. For these procedures, warfarin should be discontinued four to five days beforehand. Depending on the risk of thromboembolism, that is based on the nature of the underlying condition, the patient may require vitamin K and/or fresh frozen plasma (to ensure that coagulation parameters are within the normal range) or heparin infusions (to ensure that some degree of anticoagulation is maintained). Low molecular weight heparin is an alternative to unfractionated heparin for select cases with a high risk of thromboembolism. Warfarin therapy may generally be resumed on the night of the procedure and may be supplemented by heparin in patients with a high risk of thromboembolism. It is not necessary to discontinue acetylsalicylic acid or nonsteroidal anti-inflammatory drugs, when used in standard doses, for endoscopic procedures. There are insufficient data to make recommendations regarding newer antiplatelet drugs, such as ticlopidine or clopidogrel, but it is prudent to discontinue these medications seven to 10 days before a high-risk procedure.     

Heparin-bridging therapy is associated with post-colorectal polypectomy bleeding in patients whose oral anticoagulation therapy is interrupted

Objectives: The American and Japanese Societies for Gastrointestinal Endoscopy Guidelines recommend heparin-bridging therapy for patients whose oral anticoagulants are interrupted for endoscopic procedures. However, little is known about the potential association between heparin-bridging therapy and post-polypectomy bleeding (PPB). The aim was to investigate the incidence of PPB associated with heparin-bridging therapy administered to patients whose anticoagulants were interrupted.

Materials and methods: This was a retrospective observational study using inverse propensity analysis. Between 2013 and 2015, 1004 patients with 2863 lesions were included. The primary outcomes were the rates of PPB and thromboembolism associated with heparin-bridging therapy. The risk factors associated with PPB were identified using multivariate logistic regression analysis involving probability of treatment weighting (IPTW).

Results: The patients were categorized into a heparin-bridging therapy group (78 patients with 255 lesions) or a control group (926 patients with 2608 lesions). The PPB rate in the heparin-bridging therapy group (10.2%, 8/78) was significantly higher than in the control group (1.1%, 11/926) (p <.01). Thromboembolism occurred in one patient in the control group. The multivariate analysis revealed that heparin-bridging therapy was an independent risk factor associated with PPB (odds ratio [OR], 8.21; 95% confidence interval [95% CI], 2.32–29.10; p <.01). IPTW showed heparin-bridging therapy increased PPB (OR, 7.68; 95% CI, 1.83–32.28; p <.01).

Conclusions: Heparin-bridging therapy administered to patients whose oral anticoagulants were interrupted was associated with an increased PPB risk.     

Acute upper gastrointestinal bleeding in patients on long-term oral anticoagulation therapy： Endoscopic findings, clinical management and outcome

AIM: Acute gastrointestinal bleeding is a severe complication in patients receiving long-term oral anticoagulant therapy. The purpose of this study was to describe the causes and clinical outcome of these patients. METHODS: From January 1999 to October 2003, 111 patients with acute upper gastrointestinal bleeding (AUGIB) were hospitalized while on oral anticoagulants. The causes and clinical outcome of these patients were compared with those of 604 patients hospitalized during 2000-2001 with AUGIB who were not taking warfarin. RESULTS: The most common cause of bleeding was peptic ulcer in 51 patients (45%) receiving anticoagulants compared to 359/604 (59.4%) patients not receiving warfarin (P<0.05). No identifiable source of bleeding could be found in 33 patients (29.7%) compared to 31/604 (5.1%) patients not receiving anticoagulants (P=0.0001). The majority of patients with concurrent use of non-steroidal anti-inflammatory drugs (NSAIDs) (26/35, 74.3%) had a peptic ulcer as a cause of bleeding while 32/76 (40.8%) patients not taking a great dose of NSAIDs had a negative upper and lower gastrointestinal endoscopy. Endoscopic hemostasis was applied and no complication was reported. Six patients (5.4%) were operated due to continuing or recurrent hemorrhage, compared to 23/604 (3.8%) patients not receiving anticoagulants. Four patients died, the overall mortality was 3.6% in patients with AUGIB due to anticoagulants, which was not different from that in patients not receiving anticoagulant therapy. CONCLUSION: Patients with AUGIB while on long-term anticoagulant therapy had a clinical outcome, which is not different from that of patients not taking anticoagulants. Early endoscopy is important for the management of these patients and endoscopic hemostasis can be safely applied.     

Therapy insight: approaching endoscopy in anticoagulated patients

Over the past decade, the application of anticoagulant and antiplatelet agents for various cardiovascular and hematologic conditions has become more widespread. Optimal management of these agents during the periendoscopic period requires consideration, but limited prospective data mean that guidelines have largely relied on expert opinion. Elective procedures should be delayed in patients on temporary anticoagulation therapy (e.g. those with deep vein thrombosis). For procedures considered to have a low risk of bleeding (e.g. diagnostic endoscopy and colonoscopy without polypectomy) there is no need to discontinue or adjust anticoagulation. For procedures with a higher risk of bleeding (e.g. polypectomy and biliary sphincterotomy) an individual approach is required. This approach might include stopping oral anticoagulant therapy with or without the administration of unfractionated heparin or low-molecular-weight heparin for the preprocedure and postprocedure periods, during which the patient's international normalized ratio is in the subtherapeutic range.     

Anticoagulation and antiplatelet management in gastrointestinal endoscopy: A review of current evidence

The role of endoscopic procedures, in both diagnostic and therapeutic purposes is continually expanding and evolving rapidly. In this context, endoscopists will encounter patients prescribed on anticoagulant and antiplatelet medications frequently. This poses an increased risk of intraprocedural and delayed gastrointestinal bleeding. Thus, there is now greater importance on optimal pre, peri and post-operative management of anticoagulant and/or antiplatelet therapy to minimise the risk of post-procedural bleeding, without increasing the risk of a thromboembolic event as a consequence of therapy interruption. Currently, there are position statements and guidelines from the major gastroenterology societies. These are available to assist endoscopists with an evidenced-based systematic approach to anticoagulant and/or antiplatelet management in endoscopic procedures, to ensure optimal patient safety. However, since the publication of these guidelines, there is emerging evidence not previously considered in the recommendations that may warrant changes to our current clinical practices. Most notably and divergent from current position statements, is a growing concern regarding the use of heparin bridging therapy during warfarin cessation and its associated risk of increased bleeding, suggestive that this practice should be avoided. In addition, there is emerging evidence that anticoagulant and/or antiplatelet therapy may be safe to be continued in cold snare polypectomy for small polyps (< 10 mm).     

Comparison of postpolypectomy bleeding between epinephrine and saline submucosal injection for large colon polyps by conventional polypectomy： A prospective randomized, multicenter study

AIM:To evaluate and compare the clinical outcomes of prophylactic submucosal saline-epinephrine injection and saline injection alone for large colon polyps by conventional polypectomy. METHODS:A prospective study was conducted from July 2003 to July 2004 at 11 tertiary endoscopic centers. Large colon polyps (> 10 mm in diameter) wererandomized to undergo endoscopic polypectomy with submucosal saline-epinephrine injection (epinephrine group) or normal saline injection (saline group). Endoscopic polypectomy was performed by the conventional snare method,and early (< 12 h) and late bleeding complications (12 h-30 d) were observed. RESULTS:A total of 561 polyps in 486 patients were resected by endoscopic polypectomy. Overall,bleeding complications occurred in 7.6% (37/486) of the patients,including 4.9% (12/244) in the epinephrine group,and 10.3% (25/242) in the saline group. Early and late postpolypectomy bleeding (PPB) occurred in 6.6% (32/486) and 1% (5/486) of the patients,respectively,including 4.5% (11/244),0.4% (1/244) in the epinephrine group,and 8.7% (21/242),1.7% (4/242) in the saline group. No significant differences in the rates of overall,early and late PPB were observed between the 2 groups. Multivariate stepwise logistic regression analysis revealed that large size (> 2 cm) and neoplastic polyps were independently and significantly associated with the presence of PPB. CONCLUSION:The prophylactic submucosal injection of diluted epinephrine does not appear to provide an additional advantage over the saline injection alone for the prevention of PPB.     

Bridging of oral anticoagulation therapy for invasive procedures

The management of patients who need temporary interruption of chronic oral anticoagulant (OAC) therapy for an elective surgical or invasive procedure is problematic and complex. Patient and procedural risk factors for thrombosis and bleeding, anticoagulant-related risks of bleeding, and clinical consequences of a thrombotic or bleeding event need to be assessed and properly risk-stratified in the perioperative period. Certain procedures, such as dental, endoscopic, and cutaneous procedures, can be completed without discontinuing OAC, but most procedures with a high bleeding risk (including major surgeries) will necessitate temporary discontinuation of OAC. Bridging therapy with shorter-acting anticoagulants, such as heparin, for patients at intermediate to high risk of thromboembolism represents one strategy to maintain functional anticoagulation during this period. Large, prospective cohort studies and registries of patients on chronic OAC who underwent bridging therapy mostly with low-molecular-weight heparin have been completed recently. This paper reviews these clinical data on bridging therapy and provides an evidence-based perioperative management strategy for the at-risk patient on chronic OAC.     

Risk of major bleeding in unselected patients with venous thromboembolism.

PURPOSE: To evaluate the risk of major bleeding in unselected patients given anticoagulant treatment (heparin overlapped and followed by oral anticoagulants) because of deep vein thrombosis (DVT) or pulmonary embolism (PE). SUBJECTS AND METHODS: We screened the database of 1590 outpatients suspected of DVT and PE in prospective diagnostic studies conducted in Geneva between 1992 and 1998. RESULTS: Four hundred and eleven of 1590 patients (26%) were anticoagulated for confirmed venous thromboembolism (PE, 300; DVT, 111). One patient was excluded because of concomitant thrombolytic therapy. Five (1.2%; 95% confidence interval, 0.4-2.8) of the remaining 410 patients experienced a major hemorrhagic event during the 3-month follow-up, including two fatal events. All bleedings occurred during the first month of therapy (heparin, two; oral anticoagulants, two; combined treatment, one) and the median age of the patients who bled was 80 years. At least one serious comorbid condition associated with higher bleeding risk was present in four patients and, in one case, the bleeding was clearly related to an excessive intensity of anticoagulation. CONCLUSION: The rate of bleeding events in this population of unselected outpatients is similar to that reported in controlled therapeutic trials. The hemorrhagic events occurred early in the course of anticoagulant therapy and concerned old patients mostly affected by at least one comorbid condition. Particular care should be used to avoid the risk of overtreatment.     

Prophylactic clip application does not decrease delayed bleeding after colonoscopic polypectomy

BACKGROUND: The most common major complication of colonoscopic polypectomy is postpolypectomy hemorrhage. Although several factors have been implicated in the occurrence of hemorrhage, accurate prediction of delayed bleeding remains difficult. This randomized controlled trial evaluated the efficacy of prophylactic clip application for prevention of delayed postpolypectomy bleeding. METHODS: Postpolypectomy ulcers created by colonoscopic removal of polyps (mean size 7.8 [4.0] mm) with the endoscopic mucosal resection technique were randomly assigned to prophylactic clip placement (n = 205) or no clip (n = 208). Baseline characteristics of the patients and polyps excised were comparable between the groups. Delayed bleeding was defined as the postprocedure passage of bloody stool or massive hematochezia. The site of delayed bleeding was identified at emergent colonoscopy. RESULTS: Delayed bleeding was identified from 2 ulcers in each group from 1 to 4 days after resection (mean 2.3 days). Delayed bleeding occurred from 0.98% of ulcers in the clip group and 0.96% in the non-clip group (p > 0.9999). No patient with delayed bleeding required transfusion or surgery. CONCLUSIONS: Prophylactic clip placement did not decrease the occurrence of delayed bleeding after colonoscopic polypectomy.     

Colonoscopic polypectomy with cutting current: is it safe?

BACKGROUND: Coagulation and blended electrosurgical current are currently recommended for colonoscopic polypectomy, whereas pure cut current is believed to be associated with a higher risk of bleeding. However, the outcome of polypectomy performed with a cut current has not been evaluated in a large case series. Our objective was to study the incidence and nature of complications when polypectomy is performed with a pure cut current. METHODS: Among 9555 colonoscopic examinations, polypectomy cases were retrospectively reviewed for complications. The electrosurgical current applied was always the cutting waveform. RESULTS: Electrosurgical polypectomy using pure cut current was performed to remove 4735 lesions. Hemoclips were applied to the excision site after polypectomy to prevent bleeding in 12% of the cases. Hemorrhage occurred in 1.1% of the polypectomies (3.1% of patients). The incidence of bleeding with the different methods was snare polypectomy 0.9%, endoscopic mucosal resection 1.6%, "hot" biopsy 0.4%, and piecemeal polypectomy 7.3%. Bleeding was immediate in 66.1% of episodes and delayed in 33.9%. Patients with delayed postpolypectomy bleeding were significantly younger than those with immediate bleeding (50.5 and 64.7 years, respectively, p < 0.001). There was 1 case of transmural burn, but no perforations. CONCLUSION: Polypectomy can be performed with pure cut current with a bleeding rate comparable to that seen with the use of coagulation or blended current, provided that hemoclip placement can be used readily. Expertise in hemoclip placement is advisable if this method of polypectomy is to be used.     

Blood supply of colorectal polyps correlates with risk of bleeding after colonoscopic polypectomy

BACKGROUND: The most common complication of endoscopic polypectomy is hemorrhage. Several factors have been reported to increase the risk of hemorrhage after polypectomy, but controversies still exist. Additionally, the pathomechanism of this complication is not well understood. OBJECTIVE: To investigate the risk factors of colonoscopic postpolypectomy bleeding in patients without bleeding disorders and the blood supply of resected polyps. PATIENTS: Two hundred forty-five patients (147 men, 98 women; median age, 62.8 +/- 9.5 years [SD]) with 283 colorectal polyps, measuring > or =1 cm in diameter, were included in this prospective study. INTERVENTIONS: The polypectomies were performed using the conventional endoscopic method. Data on the patients' age and sex, as well as polyp location, size, shape, and pathology findings were recorded. The patients were observed for bleeding complications. Microscopic examination of the vascular supply of the removed polyps was performed. RESULTS: Twenty-nine postpolypectomy hemorrhages (10.2%) occurred. The bleeding rate correlated with the size, shape, and pathology results of resected polyps. The microscopic analysis revealed that sessile and thick-stalked pedunculated polyps are supplied with more vessels than other polyps. CONCLUSIONS: Patients with polyps larger than 17 mm, pedunculated polyps with a stalk diameter >5 mm, sessile polyps, and malignant lesions of the colorectal region are at high risk of hemorrhage after endoscopic excision. Moreover, on the basis of microscopic study, broad-based polyps are supplied with a considerable number of blood vessels.     

Endoscopic resection of large colorectal polyps using a clipping method

PURPOSE: In conventional endoscopic snare polypectomy, bleeding and perforation are the principal concerns. To prevent these complications, we employ an endoscopic clipping technique using the HX-3L clipping apparatus. METHODS: With this method, clips are used to clamp the base of a polyp. A snare is hung peripheral to the clips. The polyp is then resected by coagulating and cutting with an electric current. RESULTS: Neither bleeding nor perforation during or after polypectomy has occurred, nor have complications related to the use of clips developed. Gigantic polyps were not resected piecemeal, but rather were resecteden bloc facilitating a clear determination of cancer on the surface of the resected site. Endoscopic clipping permitted site marking for colonoscopic surveillance. CONCLUSION: We conclude that the clipping method has many advantages and is a useful technique in colonoscopic polypectomy.     

Improving quality measures in colonoscopy and its therapeutic intervention

Colonoscopy with polypectomy has been shown to re-duce the risk of colon cancer. The critical element in the quality of colonoscopy in terms of polyp detection and removal continues to be the performance of the endoscopist, independent of patient-related factors. Im-proved results in terms of polyp detection and complete removal have implications regarding the development of screening and surveillance intervals and the reduction of interval cancers after negative colonoscopy. Advances in colonoscopy techniques such as high-definition colonos-copy, hood-assisted colonoscopy and dye-based chro-moendoscopy have improved the detection of small and flat-type colorectal polyps. Virtual chromoendoscopy has not proven to improve polyp detection but may be use-ful to predict polyp pathology. The majority of polyps can be removed endoscopically. Available polypectomy techniques include cold forceps polypectomy, cold snare polypectomy, conventional polypectomy, endoscopic mu-cosal resection and endoscopic submucosal dissection. The preferred choice depends on the polyp size and characteristics. Other useful techniques include colono-scopic hemostasis for acute colonic diverticular bleeding, endoscopic decompression using colonoscopic stenting, and transanal tube placement for colorectal obstruction. Here we review the current knowledge concerning the improvement of quality measures in colonoscopy and colonoscopy-related therapeutic interventions.     

Anticoagulation with low molecular-weight heparin in patients with prosthetic heart valve replacements

In six patients with prosthetic heart valve replacement anticoagulation was performed with low molecular weight heparin for 4-58 weeks. The treatment was indicated because of one or more severe cerebral or gastrointestinal bleeding complications during therapy with oral anticoagulants or conventional heparin. The dose of the low molecular weight heparin ranged individually from 2,500 to 12,000 units once a day subcutaneously and was adjusted on the basis of the general bleeding tendency of the patient and the specific anticoagulant effect on factor Xa. Under this treatment no heart valve thrombosis occurred. Two minor bleeding complications were observed in two patients. All patients suffered previously from severe bleeding complications with conventional anticoagulants. One additional patient, who had been treated one year earlier with the low molecular weight heparin, again experienced embolism during treatment with only 1 X 5,000 anti factor Xa units per day. We conclude that anticoagulation with low molecular weight heparin may be recommended for patients with prosthetic heart valve replacement and severe bleeding problems with conventional anticoagulants. In patients with recurrent embolism higher doses should be administered.