PMID- 33720396 OWN - NLM STAT- MEDLINE DCOM- 20210421 LR - 20220316 IS - 1469-493X (Electronic) IS - 1361-6137 (Linking) VI - 3 IP - 3 DP - 2021 Mar 15 TI - Interventions for preventing thrombosis in solid organ transplant recipients. PG - CD011557 LID - 10.1002/14651858.CD011557.pub2 [doi] LID - CD011557 AB - BACKGROUND: Graft thrombosis is a well-recognised complication of solid organ transplantation and is one of the leading causes of graft failure. Currently there are no standardised protocols for thromboprophylaxis. Many transplant units use unfractionated heparin (UFH) and fractionated heparins (low molecular weight heparin; LMWH) as prophylaxis for thrombosis. Antiplatelet agents such as aspirin are routinely used as prophylaxis of other thrombotic conditions and may have a role in preventing graft thrombosis. However, any pharmacological thromboprophylaxis comes with the theoretical risk of increasing the risk of major blood loss following transplant. This review looks at benefits and harms of thromboprophylaxis in patients undergoing solid organ transplantation. OBJECTIVES: To assess the benefits and harms of instituting thromboprophylaxis to patients undergoing solid organ transplantation. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 10 November 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) and quasi-RCTs designed to examine interventions to prevent thrombosis in solid organ transplant recipients. All donor types were included (donor after circulatory (DCD) and brainstem death (DBD) and live transplantation). There was no upper age limit for recipients in our search. DATA COLLECTION AND ANALYSIS: The results of the literature search were screened and data collected by two independent authors. Dichotomous outcome results were expressed as risk ratio (RR) with 95% confidence intervals (CI). Random effects models were used for data analysis. Risk of bias was independently assessed by two authors using the risk of bias assessment tool. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: We identified nine studies (712 participants). Seven studies (544 participants) included kidney transplant recipients, and studies included liver transplant recipients. We did not identify any study enrolling heart, lung, pancreas, bowel, or any other solid organ transplant recipient. Selection bias was high or unclear in eight of the nine studies; five studies were at high risk of bias for performance and/or detection bias; while attrition and reporting biases were in general low or unclear. Three studies (180 participants) primarily investigated heparinisation in kidney transplantation. Only two studies reported on graft vessel thrombosis in kidney transplantation (144 participants). These small studies were at high risk of bias in several domains and reported only two graft thromboses between them; it therefore remains unclear whether heparin decreases the risk of early graft thrombosis or non-graft thrombosis (very low certainty). UFH may make little or no difference versus placebo to the rate of major bleeding events in kidney transplantation (3 studies, 155 participants: RR 2.92, 95% CI 0.89 to 9.56; I(2) = 0%; low certainty evidence). Sensitivity analysis using a fixed-effect model suggested that UFH may increase the risk of haemorrhagic events compared to placebo (RR 3.33, 95% CI 1.04 to 10.67, P = 0.04). Compared to control, any heparin (including LMWH) may make little or no difference to the number of major bleeding events (3 studies, 180 participants: RR 2.70, 95% CI 0.89 to 8.19; I(2) = 0%; low certainty evidence) and had an unclear effect on risk of readmission to intensive care (3 studies, 180 participants: RR 0.68, 95% CI 0.12 to 3.90, I(2) = 45%; very low certainty evidence). The effect of heparin on our other outcomes (including death, patient and graft survival, transfusion requirements) remains unclear (very low certainty evidence). Three studies (144 participants) investigated antiplatelet interventions in kidney transplantation: aspirin versus dipyridamole (1), and Lipo-PGE(1) plus low-dose heparin to "control" in patients who had a diagnosis of acute rejection (2). None of these reported on early graft thromboses. The effect of aspirin, dipyridamole and Lipo PGE(1) plus low-dose heparin on any outcomes is unclear (very low certainty evidence). Two studies (168 participants) assessed interventions in liver transplants. One compared warfarin versus aspirin in patients with pre-existing portal vein thrombosis and the other investigated plasmapheresis plus anticoagulation. Both studies were abstract-only publications, had high risk of bias in several domains, and no outcomes could be meta-analysed. Overall, the effect of any of these interventions on any of our outcomes remains unclear with no evidence to guide anti-thrombotic therapy in standard liver transplant recipients (very low certainty evidence). AUTHORS' CONCLUSIONS: Overall, there is a paucity of research in the field of graft thrombosis prevention. Due to a lack of high quality evidence, it remains unclear whether any therapy is able to reduce the rate of early graft thrombosis in any type of solid organ transplant. UFH may increase the risk of major bleeding in kidney transplant recipients, however this is based on low certainty evidence. There is no evidence from RCTs to guide anti-thrombotic strategies in liver, heart, lung, or other solid organ transplants. Further studies are required in comparing anticoagulants, antiplatelets to placebo in solid organ transplantation. These should focus on outcomes such as early graft thrombosis, major haemorrhagic complications, return to theatre, and patient/graft survival. CI - Copyright (c) 2021 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. FAU - Surianarayanan, Vignesh AU - Surianarayanan V AD - Medical School, Newcastle University, Newcastle upon Tyne, UK. FAU - Hoather, Thomas J AU - Hoather TJ AD - Department of Education, Newcastle University, Newcastle Upon Tyne, UK. FAU - Tingle, Samuel J AU - Tingle SJ AD - NIHR Blood and Transplant Research Unit, Newcastle University and Cambridge University, Newcastle upon Tyne, UK. FAU - Thompson, Emily R AU - Thompson ER AD - Institute of Transplantation, The Freeman Hospital, Newcastle upon Tyne, UK. FAU - Hanley, John AU - Hanley J AD - Department of Haematology, Newcastle upon Tyne Acute Hospitals, Newcastle upon Tyne, UK. FAU - Wilson, Colin H AU - Wilson CH AD - Institute of Transplantation, The Freeman Hospital, Newcastle upon Tyne, UK. LA - eng PT - Journal Article PT - Meta-Analysis PT - Research Support, Non-U.S. Gov't PT - Systematic Review DEP - 20210315 PL - England TA - Cochrane Database Syst Rev JT - The Cochrane database of systematic reviews JID - 100909747 RN - 0 (Anticoagulants) RN - 0 (Heparin, Low-Molecular-Weight) RN - 0 (Placebos) RN - 0 (Platelet Aggregation Inhibitors) RN - 5Q7ZVV76EI (Warfarin) RN - 64ALC7F90C (Dipyridamole) RN - 9005-49-6 (Heparin) RN - R16CO5Y76E (Aspirin) SB - IM UOF - doi: 10.1002/14651858.CD011557 MH - Anticoagulants/adverse effects/therapeutic use MH - Aspirin/therapeutic use MH - Bias MH - Dipyridamole/therapeutic use MH - Hemorrhage/chemically induced MH - Heparin/adverse effects/therapeutic use MH - Heparin, Low-Molecular-Weight/adverse effects/therapeutic use MH - Humans MH - Kidney Transplantation/*adverse effects/statistics & numerical data MH - Liver Transplantation/*adverse effects/statistics & numerical data MH - Placebos/therapeutic use MH - Platelet Aggregation Inhibitors/therapeutic use MH - Postoperative Complications/*prevention & control MH - Randomized Controlled Trials as Topic MH - Thrombosis/*prevention & control MH - *Transplant Recipients MH - Warfarin/therapeutic use PMC - PMC8094924 COIS- Vignesh Surianarayanan has declared that they have no conflict of interest. Thomas J Hoather has declared that they have no conflict of interest. Samuel J Tingle has declared that they have no conflict of interest. Emily Thompson has declared that they have no conflict of interest. John Hanley has declared that they have no conflict of interest. Colin H Wilson has declared that they have no conflict of interest. EDAT- 2021/03/16 06:00 MHDA- 2021/04/22 06:00 PMCR- 2022/03/15 CRDT- 2021/03/15 13:18 PHST- 2021/03/15 13:18 [entrez] PHST- 2021/03/16 06:00 [pubmed] PHST- 2021/04/22 06:00 [medline] PHST- 2022/03/15 00:00 [pmc-release] AID - CD011557.pub2 [pii] AID - 10.1002/14651858.CD011557.pub2 [doi] PST - epublish SO - Cochrane Database Syst Rev. 2021 Mar 15;3(3):CD011557. doi: 10.1002/14651858.CD011557.pub2.