bleeds were fatal. Patients were excluded from the trial if they had a mechanical heart valve or a recent (within previous 12 weeks) stroke, embolism, or transient ischemic attack. The PERIOP-2 trial assessed 1471 patients with atrial fibrillation or a mechanical heart valve who required warfarin interruption for an elective surgery/procedure [49]. A mechanical heart valve was present in 21 percent (mitral in 9 percent; aortic in 12 percent). Before the surgery/procedure, all patients received bridging with the LMW heparin dalteparin, 200 IU/kg daily (100 IU/kg daily on the day before the surgery/procedure). After the surgery/procedure, patients were randomly assigned to receive dalteparin 200 IU/kg daily (fixed-dose 5,000 IU daily in patients at high-bleed-risk) or placebo until the INR was 2.0 and were followed for 12 weeks. There was no significant difference in the risk of major thromboembolism (for atrial fibrillation, 1.41 versus 0.75 percent, p = 0.27; for mechanical valves, 0 versus 0.67 percent, p = 0.49) or for major bleeding (for atrial fibrillation, 2.62 versus 1.64 percent, p = 0.25; for mechanical valves, 1.96 versus 0.67 percent, p = 0.62). Bridging versus no bridging did not affect major outcomes in patients who required a major procedure during participation in large anticoagulation trials for atrial fibrillation, https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 23/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate including the RE-LY (warfarin versus dabigatran), ROCKET-AF (warfarin versus rivaroxaban), and ARISTOTLE (warfarin versus apixaban) trials [9-11]. In the RE-LY trial, patients receiving warfarin had more thromboembolic events associated with bridging than with non-use of bridging (1.8 versus 0.3 percent); patients who received bridging also had a higher risk of major bleeding (warfarin: 6.8 percent with bridging, 1.6 percent without; dabigatran: 6.5 percent with bridging, 1.8 percent without) [61]. Additional real world data come from the ORBIT-AF and Dresden registries. ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) is a community-based registry of outpatients with atrial fibrillation receiving any oral anticoagulant; in this study, 2200 of 7372 individuals (30 percent) had interruption of anticoagulation for a procedure [62]. Bridging was used in 24 percent of these interruptions, especially in patients with a history of stroke or a mechanical heart valve and/or receiving warfarin; bleeding events were more common in individuals who received bridging compared with those who did not receive bridging (5 versus 1.3 percent). A composite endpoint that included major bleeding, myocardial infarction, stroke, systemic embolism, hospitalization, or death within 30 days was also higher in those who received bridging (13 versus 6.3 percent). In the Dresden NOAC registry, over 800 patients who were receiving dabigatran, rivaroxaban, or apixaban for any indication and underwent an invasive procedure had similar rates of major cardiovascular events if they received bridging, no bridging, or no anticoagulant discontinuation [63]. Bridging was not an independent risk factor for major bleeding; however, individuals undergoing major procedures were more likely to receive bridging and to have major bleeding. Supporting evidence for the practice of avoiding bridging in other groups includes the following: VTE In a systematic review from 2019 that evaluated patients who were receiving a vitamin K antagonist to treat venous thromboembolism (VTE; 28 cohort studies that included nearly 7000 procedures), the pooled incidence of recurrent VTE was similar with and without bridging [64]. The risk of bleeding was generally higher when bridging was used. Any indication for anticoagulation In a large systematic review and meta-analysis involving 34 studies (33 observational and one randomized) in patients receiving a vitamin K antagonist for any indication who were undergoing elective surgery or procedures. there was no significant difference in the rate of thromboembolism in patients who received bridging compared with patients who did not (odds ratio [OR] 0.80; 95% CI 0.42-1.54) [65]. https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 24/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate Bridging was associated with a threefold increase in major bleeding compared with no bridging (OR 3.60; 95% CI 1.52-8.50); full-dose heparin was associated with an increase in overall bleeding compared with lower heparin doses (OR 2.28; 95% CI 1.27-4.08). (See 'Heparin product and dose' below.) A potential role for bridging in reducing the risk of "rebound hypercoagulability" has also been proposed; however, this premise is not supported by data from the BRIDGE trial discussed above [48]. Heparin product and dose Typically, LMW heparins are used for bridging, as they have similar efficacy compared with unfractionated heparin, are more convenient to use, and generally do not require monitoring. Intravenous unfractionated heparin is less costly and can be reversed more rapidly than subcutaneous LMW heparin; it may be a reasonable alternative in some individuals. We prefer LMW heparin for bridging anticoagulation in individuals with a very high risk of arterial thromboembolism (eg, rheumatic heart disease, atrial fibrillation with recent embolic stroke, high-risk mechanical heart valve) and those with a moderate risk of thromboembolism (eg, active cancer) [27,28,66]. Perioperative anticoagulation management in individuals with prosthetic heart valves is discussed in detail separately. (See "Anticoagulation for prosthetic heart valves: Management of bleeding and invasive procedures", section on 'Planning for invasive procedures'.) For individuals with impaired kidney function and/or those requiring hemodialysis, intravenous or subcutaneous unfractionated heparin can be used more easily because dosing is unaffected by kidney function [67]. (See "Heparin and LMW heparin: Dosing and adverse effects", section on 'LMW heparin standard dosing'.) There are no data on using the direct oral anticoagulants (DOACs) as bridging agents. We do not use any of the DOACs for bridging. Heparins can be dosed at prophylactic doses, therapeutic doses, or doses intermediate between the two. The term "therapeutic dose" refers to doses typically used for treatment of thromboembolic disease, despite the fact that in this case it is being used prophylactically (to prevent thromboembolism). There are no clinical trial data or practice standards to guide dosing, and clinical judgment is required to determine the appropriate dose for each patient [65,68,69]. https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 25/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate Therapeutic dosing Therapeutic dosing (also called "full dose") is appropriate for bridging anticoagulation for individuals with a potential arterial thromboembolic source (eg, atrial fibrillation, mechanical heart valve) or VTE within the preceding month. Typical regimens include enoxaparin, 1 mg/kg subcutaneously twice daily or dalteparin, 100 units/kg subcutaneously twice daily. Intermediate dosing Intermediate-dose anticoagulation may be appropriate for individuals with atrial fibrillation or VTE within the preceding month when bridging is needed but concerns about bleeding are greater. Typical regimens include enoxaparin, 40 mg twice daily, or dalteparin, 5000 units subcutaneously twice daily. Prophylactic dosing Prophylactic-dose anticoagulation (also called "low dose") generally is not used for bridging in patients with atrial fibrillation, because there is no evidence that prophylactic-dose heparin prevents stroke in this setting. This dose level may be reasonable in patients who have had a VTE event within the preceding 3 to 12 months. Typical prophylactic regimens include enoxaparin, 40 mg once daily, or dalteparin, 5000 units subcutaneously once daily. The use of prophylactic-dose heparin for postoperative VTE prevention in patients not receiving ongoing anticoagulation is discussed separately. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".) Additional details regarding heparin products, including dose adjustments for obesity and impaired kidney function, are provided separately. (See "Heparin and LMW heparin: Dosing and adverse effects".) Timing of bridging Once a decision to use bridging has been made, the next decision is whether to use bridging before the procedure, after the procedure, or both ( table 7). Sample bridging protocols are provided on the Thrombosis Canada website. Atrial fibrillation As noted above, we suggest not using bridging for most patients with atrial fibrillation. (See 'Limited indications for bridging' above.) However, for individuals for whom bridging is used due to a very high risk of thromboembolism, we use bridging both preoperatively and postoperatively [14]. Warfarin is usually resumed 12 to 24 hours after surgery, typically the evening of the day of surgery or the evening of the day after surgery, as long as adequate hemostasis has been achieved. (See 'Warfarin interruption' above.) Venous thromboembolism https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 26/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate First three months For individuals within the first three months after an acute episode of VTE, we use bridging both preoperatively and postoperatively, typically with therapeutic-dose LMW heparin (eg, enoxaparin 1 mg/kg twice daily) [14]. This practice is based on the high incidence of recurrence without anticoagulation. While postoperative intravenous heparin doubles the rate of bleeding, there is a net reduction in serious morbidity in such patients because the risk of postoperative recurrent VTE is high. (See 'Preoperative timing of bridging' below and 'Postoperative timing of bridging' below.) In selected patients in whom surgery cannot be delayed beyond the first month after the diagnosis of an acute VTE, it may be appropriate to use a temporary inferior vena cava (IVC) filter, especially if bridging anticoagulation cannot be used postoperatively due to high bleeding risk. (See "Overview of the treatment of proximal and distal lower extremity deep vein thrombosis (DVT)", section on 'Patients at high risk of bleeding' and "Treatment, prognosis, and follow-up of acute pulmonary embolism in adults", section on 'Inferior vena cava filters'.) Greater than three months For individuals greater than three months after an acute episode of VTE, we generally use postoperative bridging, typically with a low-dose LMW heparin regimen (eg, enoxaparin 40 mg daily), but not preoperative bridging [70]. For patients who are undergoing a minor procedure or day surgery, bridging is probably not justified. This practice is based on the significantly reduced risk of VTE recurrence after the first month [71,72]. (See 'Postoperative timing of bridging' below.) Preoperative timing of bridging We generally initiate heparin bridging three days before a planned procedure (ie, two days after stopping warfarin), when the prothrombin time/international normalized ratio (PT/INR) has started to drop below the therapeutic range. LMW heparin We discontinue low molecular weight (LMW) heparin 24 hours before the planned surgery or procedure, based on a biologic half-life of most subcutaneous LMW heparins of approximately three to five hours [8,66,73]. If a twice-daily LMW heparin regimen is given, the evening dose the night before surgery is omitted, whereas if a once- daily regimen is given (eg, dalteparin 200 international units/kg), one-half of the total daily dose is given on the morning of the day before surgery. This ensures that no significant residual anticoagulant will be present at the time of surgery, based on studies that have shown a residual anticoagulant effect at 24 hours after stopping therapeutic-dose LMW heparin, and it is consistent with the 2012 American College of Chest Physicians (ACCP) Guidelines [8,12,74,75]. https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 27/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate Unfractionated heparin For therapeutic-dose unfractionated heparin, we continue the intravenous infusion until four to five hours before the procedure, based on the biologic half-life of intravenous unfractionated heparin of approximately 45 minutes [8,73,74]. If subcutaneous unfractionated heparin is used, typically with a dose of approximately 250 international units/kg twice daily, the last dose can be given the evening before the procedure. Postoperative timing of bridging Postoperative resumption of unfractionated heparin and LMW heparin is similar, based on the onset of anticoagulation at approximately one hour after administration for both forms of heparin, and peak anticoagulant activity at approximately three to five hours. The resumption of bridging, especially when given as a therapeutic-dose regimen, should be delayed until there is adequate hemostasis based on a clinical assessment of the wound site, drainage fluid amount, and expected postoperative bleeding; coupled, where appropriate, with hemoglobin levels [76]. This assessment will vary depending on the surgery type and individual patient considerations, and it may be difficult for surgery where ongoing bleeding is not readily apparent (eg, cardiac, intracranial). A slight delay in resumption of postoperative anticoagulation is preferable to premature initiation of postoperative bridging that results in bleeding, which ultimately will lengthen the period without an anticoagulant and thus increase thromboembolic risk. For those undergoing major surgery or those with a high bleeding risk procedure, therapeutic-dose unfractionated heparin or LMW heparin should be delayed for 48 to 72 hours after hemostasis has been secured [8]. For most minor procedures associated with a low bleeding risk in which bridging is used (eg, laparoscopic hernia repair), therapeutic-dose unfractionated heparin or LMW heparin can usually be resumed 24 hours after the procedure. Resumption of bridging anticoagulation too early, especially the use of therapeutic-dose heparin within 24 hours after surgery, is associated with a two- to fourfold increased risk for major bleeding compared with no bridging or prophylactic-dose heparin. The increased bleeding risk was demonstrated in the Prospective peri-operative enoxaparin cohort trial (PROSPECT), which evaluated bleeding risk in a cohort of 260 patients undergoing major surgery whose treating clinicians used bridging anticoagulation [77]. In this trial, nine patients had major postoperative bleeding (3.5 percent), most on postoperative day 0, and 19 (7.3 percent) had minor bleeding. https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 28/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate Postoperatively, warfarin is generally resumed on the same postoperative day as the heparin. Heparin can be discontinued when the INR reaches the therapeutic range for individuals at moderate thromboembolism risk. Individuals with heparin-induced thrombocytopenia Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening condition in which heparin-induced antibodies to platelets can cause thrombocytopenia and/or venous or arterial thrombosis. (See "Clinical presentation and diagnosis of heparin-induced thrombocytopenia".) Patients with HIT should not receive any heparin (eg, they should not receive heparin flushes, unfractionated heparin, or LMW heparin). Non-heparin anticoagulants that can be used in patients with HIT are discussed separately. (See "Management of heparin-induced thrombocytopenia", section on 'Anticoagulation'.) URGENT/EMERGENCY INVASIVE PROCEDURE Reversal of the patient's usual anticoagulant may be required for more urgent or emergency surgery or procedures or to treat perioperative bleeding. Agents with a potential prothrombotic effect (eg, prothrombin complex concentrates [PCCs], plasma products, immediate reversal agents) should be reserved for the treatment of severe, life-threatening bleeding or anticipated severe bleeding (eg, intracranial hemorrhage, emergency major surgery with elevated prothrombin time/international normalized ratio [PT/INR]). Agent-specific strategies include the following: Warfarin For individuals who require reversal of warfarin or other vitamin K antagonists, the appropriate reversal strategy is determined by the degree of anticoagulation (eg, PT/INR, clinical bleeding), urgency of the procedure, and degree of bleeding risk ( table 8). If semi-urgent reversal of warfarin is required (eg, within one to two days), warfarin should be withheld and vitamin K administered (eg, 2.5 to 5 mg of oral or intravenous vitamin K). (See "Management of warfarin-associated bleeding or supratherapeutic INR", section on 'Urgent surgery/procedure'.) If immediate reversal is required (eg, for emergency surgery or active bleeding), this can be achieved via the use of PCCs or plasma products (eg, Fresh Frozen Plasma [FFP], Plasma Frozen Within 24 Hours After Phlebotomy [PF24]) along with vitamin K ( table 9) [78,79]. The 4-factor PCCs contain adequate amounts of all vitamin K- dependent clotting factors, whereas 3-factor PCCs may require supplementation with https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 29/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate FFP for adequate factor VII ( table 10). Of note, there is a thrombotic risk associated with these products, and they should be used only if there is life-threatening bleeding and prolongation of the INR by a vitamin K antagonist [79]. (See "Management of warfarin-associated bleeding or supratherapeutic INR", section on 'Serious/life- threatening bleeding'.) Dabigatran Dabigatran is an oral direct thrombin inhibitor; it can be reversed by idarucizumab ( table 11). In an open-label study involving 503 patients who had bleeding or required emergency surgery, idarucizumab effectively reversed the anticoagulant effect of dabigatran [80]. The use of this agent as well as other potential strategies for individuals receiving dabigatran who are at great risk of serious bleeding with an emergency procedure are presented separately. (See "Management of bleeding in patients receiving direct oral anticoagulants".) Rivaroxaban, apixaban, and edoxaban Rivaroxaban, apixaban, and edoxaban are oral direct factor Xa inhibitors; these anticoagulants can be reversed by andexanet alfa or a PCC ( table 11). These and other potential strategies for individuals receiving these agents who are at great risk of serious bleeding with an urgent/emergency procedure are presented separately. (See "Management of bleeding in patients receiving direct oral anticoagulants".) Algorithms for anticoagulant reversal depending on the severity of bleeding are provided by various societies and groups such as Thrombosis Canada. Additional discussions of postoperative bleeding are presented separately. (See "Postoperative complications among patients undergoing cardiac surgery", section on 'Hematologic dysfunction'.) NEURAXIAL ANESTHESIA Neuraxial (ie, spinal or epidural) anesthesia should not be used in anticoagulated individuals, due to the risk of potentially catastrophic bleeding into the epidural space. The increased risk of bleeding applies both at the time of catheter placement and the time of removal. If neuraxial anesthesia is considered for surgical anesthesia or postoperative pain control, the timing of anesthesia and anticoagulant administration should be coordinated to optimize the safe use of both. Early consultation with the anesthesiologist is advised. This subject is discussed in detail separately. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication".) https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 30/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate The timing of anticoagulant use in patients receiving neuraxial anesthesia is illustrated by evidence-based guidelines from the American Society of Regional Anesthesia (ASRA), which suggest the following [81,82]: Prophylactic-dose low molecular weight (LMW) heparin (eg, enoxaparin, 40 mg once daily): Before surgery, wait at least 10 to 12 hours after the last dose of LMW heparin is administered before a spinal/epidural catheter is placed. After surgery, when there is adequate surgical site hemostasis, wait at least six to eight hours after catheter removal before resuming treatment with LMW heparins. Therapeutic-dose LMW heparin (eg, enoxaparin, 1 mg/kg twice daily): Before surgery, wait at least 24 hours after the last dose of LMW heparin is administered before a spinal/epidural catheter is placed. After surgery, when there is adequate surgical site hemostasis, for twice daily dosing, wait at least 24 hours after catheter removal before resuming therapeutic-dose LMW heparin. For once daily dosing, wait at least six to eight hours after catheter removal before the first dose; the second postoperative dose should occur no sooner than 24 hours after the first dose. SOCIETY GUIDELINE LINKS Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Anticoagulation".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 31/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topics (see "Patient education: Taking oral medicines for blood clots (The Basics)" and "Patient education: Choosing an oral medicine for blood clots (The Basics)") Beyond the Basics topics (see "Patient education: Warfarin (Beyond the Basics)") SUMMARY AND RECOMMENDATIONS Balancing thromboembolic and bleeding risk Interruption of anticoagulation temporarily increases thromboembolic risk, and continuing anticoagulation increases the risk of bleeding. We take into account these risks, along with specific features of the anticoagulant the patient is taking. Internet-based resources and case examples are provided above. (See 'Overview of our approach' above.) Thromboembolic risk Those at very high or high thromboembolic risk should limit the period without anticoagulation to the shortest possible interval ( table 1). If thromboembolic risk is transiently increased (eg, recent stroke, recent pulmonary embolism), we prefer to delay surgery until the risk returns to baseline, if possible. (See 'Estimating thromboembolic risk' above.) Atrial fibrillation We estimate thromboembolic risk for patients with atrial fibrillation based on clinical variables including age and comorbidities. In the RE-LY (Randomized Evaluation of Long-Term Anticoagulant Therapy) trial, the perioperative thromboembolic risk was 1.2 percent based on a composite endpoint of stroke, cardiovascular death, and pulmonary embolus. The risk of recurrent arterial embolism from any cardiac source is approximately 0.5 percent per day in the first month after an acute event. (See 'Atrial fibrillation' above and "Atrial fibrillation in adults: Use of oral anticoagulants".) Prosthetic heart valve The risks of thromboembolism and perioperative management of patients with bioprosthetic and mechanical heart valves are discussed separately. (See "Anticoagulation for prosthetic heart valves: Management of bleeding and invasive procedures", section on 'Planning for invasive procedures' and "Diagnosis of mechanical prosthetic valve thrombosis or obstruction".) https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 32/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate Recent thromboembolism The perioperative risk of venous thromboembolism (VTE) is greatest in individuals with an event within the prior three months, and those with a history of VTE associated with a high-risk inherited thrombophilia. Patients who require surgery within the first three months following an episode of VTE are likely to benefit from delaying elective surgery, even if the delay is only for a few weeks. (See 'Recent thromboembolism' above.) Bleeding risk A higher bleeding risk confers a greater need for perioperative hemostasis, and hence a longer period of anticoagulant interruption. Bleeding risk is dominated by the type and urgency of surgery ( table 2); some patient comorbidities (eg, older age, decreased kidney function) and medications that affect hemostasis also contribute. (See 'Estimating procedural bleeding risk' above and 'Deciding whether to interrupt anticoagulation' above.) High risk High bleeding risk procedures include coronary artery bypass surgery, kidney biopsy, and any procedure lasting >45 minutes. In general, the anticoagulant must be discontinued if the surgical bleeding risk is high. (See 'Settings requiring anticoagulant interruption' above.) Low risk Low bleeding risk procedures include dental extractions, minor skin surgery, cholecystectomy, carpal tunnel repair, and abdominal hysterectomy. Individuals undergoing selected low bleeding risk surgery often can continue their anticoagulant. (See 'Settings in which continuing the anticoagulant may be preferable' above.) Cardiac implantable device or catheter ablation for atrial fibrillation Continuing warfarin was associated with a lower risk of bleeding in patients on the BRUISE CONTROL trial who were undergoing implantation of a cardiac implantable electronic device (eg, pacemaker, implantable cardioverter-defibrillator) and patients on the COMPARE trial who were undergoing catheter ablation for atrial fibrillation. (See 'Overview of whether to interrupt' above and "Cardiac implantable electronic devices: Periprocedural complications".) Timing of interruption The timing of interruption depends on the periprocedural bleeding risk and the specific anticoagulant. The algorithm summarizes our approach ( algorithm 1). The figure illustrates the timing of direct oral anticoagulant (DOAC) interruption ( figure 1). (See 'Timing of anticoagulant interruption' above.) Bridging Bridging anticoagulation involves the administration of a short-acting anticoagulant, typically a low molecular weight (LMW) heparin, during the interruption of a https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 33/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate longer-acting agent, typically warfarin. The intent is to minimize the risk of perioperative thromboembolism. For most individuals, bridging increases bleeding risk without lowering thromboembolic risk, and we suggest not using bridging (Grade 2B). We feel more strongly about avoiding bridging the lower the baseline thromboembolic risk and the higher the bleeding risk. We generally do not use bridging for DOACs. (See 'Limited indications for bridging' above.) For selected patients on warfarin (eg, stroke, systemic embolism, or transient ischemic attack within the previous three months; atrial fibrillation and very high risk of stroke [eg, CHADS score of 5 or 6]; VTE within the previous three months; recent coronary stenting; 2 previous thromboembolism during interruption of chronic anticoagulation), we suggest the use of bridging (Grade 2C). Agent When bridging is used, we prefer LMW heparin for most patients. An exception is an individual with impaired kidney function and/or hemodialysis requirement, for whom intravenous or subcutaneous unfractionated heparin can be used more easily. We do not use DOACs for bridging. Non-heparin anticoagulants that can be used in patients with heparin-induced thrombocytopenia are discussed separately. (See 'Heparin product and dose' above.) Timing Bridging can be used preoperatively, postoperatively, or both, depending on the underlying condition for which the patient is being anticoagulated ( table 7). The timing depends on the heparin product used and the procedural bleeding risk. Importantly, resumption of bridging anticoagulation too early is associated with an increased risk for major bleeding. (See 'Timing of bridging' above.) The role of bridging in individuals with mechanical heart valves is discussed separately. (See "Anticoagulation for prosthetic heart valves: Management of bleeding and invasive procedures".) Urgent/Emergency procedure Reversal of the patient's usual anticoagulant may be required for more urgent or emergency procedures or to treat perioperative bleeding. Agents with a potential prothrombotic effect (eg, immediate reversal agents, prothrombin complex concentrates, plasma products) should be reserved for the treatment of life- threatening, severe bleeding or anticipated severe bleeding (intracranial hemorrhage, emergency major surgery). (See 'Urgent/emergency invasive procedure' above and "Management of bleeding in patients receiving direct oral anticoagulants".) Use of UpToDate is subject to the Terms of Use. https://www.uptodate.com/contents/perioperative-management-of-patients-receiving-anticoagulants/print 34/65 7/5/23, 10:17 AM Perioperative management of patients receiving anticoagulants - UpToDate REFERENCES 1. Douketis JD. Perioperative management of patients who are receiving warfarin therapy: an evidence-based and practical approach. Blood 2011; 117:5044. 2. Spyropoulos AC, Douketis JD. How I treat anticoagulated patients undergoing an elective procedure or surgery. Blood 2012; 120:2954. 3. Torn M, Rosendaal FR. 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