Stroke Prevention With Prophylactic Left Atrial Appendage Occlusion in Cardiac Surgery Patients Without Atrial Fibrillation: A Meta-Analysis of Randomized and Propensity-Score Studies.

BACKGROUND: The role of left atrial appendage occlusion (LAAO) in patients without previous atrial fibrillation (AF) is not established. This meta-analysis was conducted on patients with normal sinus rhythm who underwent cardiac surgery, with and without concomitant LAAO, to evaluate its effect on the incidence of cerebrovascular accidents (CVAs). METHODS: A systematic review was conducted from inception until December 2023 for randomized and propensity-score studies comparing CVA in patients without AF undergoing cardiac surgery with or without LAAO. RESULTS: Six studies met our inclusion criteria with a total of 4130 patients: 2146 in the LAAO group and 1984 in the no-LAAO group. The risk ratio of postoperative AF was 1.05 (95% CI, 0.86-1.28); P=0.628. The CVA rates at 5 years were 6.8±1.0% in the no-LAAO group and 4.3±0.8% in the LAAO group (log-rank P=0.021). The Cox regression analysis for CVA in patients undergoing LAAO reported a hazard ratio of 0.65 (95% CI, 0.45-0.94); P=0.022. Landmark analysis at 4 years highlighted a significant difference in overall survival between no-LAAO and LAAO groups, 86±12.2% versus 89.6±11.0%; P=0.041. CONCLUSIONS: In this meta-analysis of patients without previous AF undergoing cardiac surgery, LAAO was associated with a decreased risk of CVA, no difference in the incidence of postoperative atrial fibrillation, and a significant overall survival benefit at a 4-year landmark analysis. Although these findings support LAAO, the randomized LeAAPS trial (Left Atrial Appendage Exclusion for Prophylactic Stroke Reduction Trial), LAA-CLOSURE trial (A Randomized Prospective Multicenter Trial for Stroke Prevention by Prophylactic Surgical Closure of the Left Atrial Appendage in Patients Undergoing Bioprosthetic Aortic Valve Surgery), and LAACS-2 trial (Left Atrial Appendage Closure by Surgery-2) will help define the effectiveness of LAAO in patients undergoing cardiac surgery who have risk factors for AF and CVA. REGISTRATION: URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42024496366.

A Systematic Review of Ongoing Registered Research Studies on Post-Operative Atrial Fibrillation after Cardiac Surgery.

Background/Objectives: New-onset atrial fibrillation (AF) after cardiac surgery is associated with patient-important outcomes. Uncertainty persists regarding its prevention, detection, and management. This review seeks to identify, compile, and describe ongoing registered research studies involving patients with or at risk for post-operative AF (POAF) after cardiac surgery. Methods: We searched clinical trial registries in January 2023 for studies focusing on POAF prediction, prevention, detection, or management. We extracted data from each record and performed descriptive analyses. Results: In total, 121 studies met the eligibility criteria, including 82 randomized trials. Prevention studies are the most common (n = 77, 63.6%), followed by prediction (n = 21, 17.4%), management (n = 16, 13.2%), and detection studies (n = 7, 5.8%). POAF after cardiac surgery is an area of active research. Conclusions: There are many ongoing randomized prevention studies. However, two major clinical gaps persist; future randomized trials should compare rate and rhythm control in patients who develop POAF, and long-term follow-up studies should investigate strategies to monitor for AF recurrence in patients with POAF.

Topical Versus Intravenous Tranexamic Acid in Patients Undergoing Cardiac Surgery: The DEPOSITION Randomized Controlled Trial.

BACKGROUND: Although intravenous tranexamic acid is used in cardiac surgery to reduce bleeding and transfusion, topical tranexamic acid results in lower plasma concentrations compared to intravenous tranexamic acid, which may lower the risk of seizures. We aimed to determine whether topical tranexamic acid reduces the risk of in-hospital seizure without increasing the risk of transfusion among cardiac surgery patients. METHODS: We conducted a multicenter, double dummy, blinded, randomized controlled trial of patients recruited by convenience sampling in academic hospitals undergoing cardiac surgery with cardiopulmonary bypass. Between September 17, 2019, and November 28, 2023, a total of 3242 patients from 16 hospitals in 6 countries were randomly assigned (1:1 ratio) to receive either intravenous tranexamic acid (control) through surgery or topical tranexamic acid (treatment) at the end of surgery. The primary outcome was seizure, and the secondary outcome was red blood cell transfusion. After the last planned interim analysis-when 75% of anticipated participants had completed follow up-the Data and Safety Monitoring Board recommended to terminate the trial, and upon unblinding, the Operations Committee stopped the trial for safety. RESULTS: Among 3242 randomized patients (mean age, 66.0 years; 77.7% male), in-hospital seizure occurred in 4 of 1624 patients (0.2%) in the topical group and in 11 of 1628 patients (0.7%) in the intravenous group (absolute risk difference, -0.5%; 95% CI, -0.9 to 0.03; P = .07). Red blood cell transfusion occurred in 570 patients (35.1%) in the topical group and in 433 (26.8%) in the intravenous group (absolute risk difference, 8.3%; 95% CI, 5.2 to 11.5; P = .007). The absolute risk difference in transfusion of ≥4 units of red blood cells in the topical group compared to the intravenous group was 8.2% (95% CI, 3.4 to 12.9). CONCLUSIONS: Among patients having cardiac surgery, topical administration of tranexamic acid resulted in an 8.3% absolute increase in transfusion without reducing the incidence of seizure, compared to intravenous tranexamic acid.

Recurrence of new-onset post-operative AF after cardiac surgery: detected by implantable loop recorders: A systematic review and Meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is one of the most common complications after cardiac surgery. New-onset post-operative AF may signal an elevated risk of AF and associated outcomes in long-term follow-up. We aimed to estimate the rate of AF recurrence as detected by an implantable loop recorder (ILR) in patients experiencing post-operative AF within 30 days after cardiac surgery. METHODS: We searched MEDLINE, Embase and Cochrane CENTRAL to April 2023 for studies of adults who did not have known AF, experienced new-onset AF within 30 days of cardiac surgery and received an ILR. We pooled individual participant data on timing of AF recurrence using a random-effects model with a frailty model applied to a Cox proportional hazard analysis. RESULTS: From 8671 citations, 8 single-centre prospective cohort studies met eligibility criteria. Data were available from 185 participants in 7 studies, with a median follow-up of 1.7 (IQR: 1.3-2.8) years. All included studies were at a low risk of bias. Pooled AF recurrence rates following 30 post-operative days were 17.8% (95% CI 11.9%-23.2%) at 3 months, 24.4% (17.7%-30.6%) at 6 months, 30.1% (22.8%-36.7%) at 12 months and 35.3% (27.6%-42.2%) at 18 months. CONCLUSIONS: In patients who experience new-onset post-operative AF after cardiac surgery, AF recurrence lasting at least 30 s occurs in approximately 1 in 3 in the first year after surgery. The optimal frequency and modality to use for monitoring for AF recurrence in this population remain uncertain.

Strategies to reduce out-of-pocket medication costs for Canadians with peripheral arterial disease.

BACKGROUND: Given that peripheral arterial disease (PAD) disproportionately affects people of lower socioeconomic status, out-of-pocket expenses for preventive medications are a major barrier to their use. We carried out a cost comparison of drug therapies for PAD to identify prescribing strategies that minimize out-of-pocket expenses for these medications. METHODS: Between March and June 2019, we contacted outpatient pharmacies in Hamilton, Ontario, Canada, to assess pricing of pharmacologic therapies at dosages included in the 2016 American College of Cardiology/American Heart Association guideline for management of lower extremity PAD. We also gathered pricing information for supplementary charges, including delivery, pill splitting and blister packaging. We calculated prescription prices with and without dispensing fees for 30-day brand-name and generic prescriptions, and 90-day generic prescriptions. RESULTS: Twenty-four pharmacies, including hospital-based, independent and chain, were included in our sample. In the most extreme scenario, total 90-day medication costs could differ by up to $1377.26. Costs were affected by choice of agent within a drug class, generic versus brand-name drug, quantity dispensed, dispensing fee and delivery cost, if any. CONCLUSION: By opting for prescriptions for 90 days or as long as possible, selecting the lowest-cost generic drugs available in each drug class, and identifying dispensing locations with lower fees, prescribers can minimize out-of-pocket patient medication expenses. This may help improve adherence to guideline-recommended therapies for the secondary prevention of vascular events in patients with PAD.

Landiolol for the prevention of postoperative atrial fibrillation after cardiac surgery: a systematic review and meta-analysis.

PURPOSE: Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery. Although the evidence suggests that beta blockers prevent POAF, they often cause hypotension. Landiolol, an ultra-short-acting ß1 blocker, may prevent POAF, without adverse hemodynamic consequences. SOURCE: We searched MEDLINE, CENTRAL, Embase, and trial registries between January 1970 and March 2022. We included randomized controlled trials (RCTs) that evaluated the effect of landiolol for the prevention of POAF after cardiac surgery. Two reviewers independently assessed eligibility, extracted data, and assessed risk of bias using the Risk of Bias 2.0 tool. We pooled data using random-effects models. We used the Grading of Recommendations, Assessment, Development and Evaluations framework to assess certainty of evidence. PRINCIPAL FINDINGS: Nine RCTs including 868 participants met the eligibility criteria. Patients randomized to landiolol (56/460) had less POAF compared with controls (133/408) with a relative risk (RR) of 0.40 (95% confidence interval [CI], 0.30 to 0.54; I2 = 0%;) and an absolute risk of 12.2% vs 32.6% (absolute risk difference, 20.4%; 95% CI, 15.0 to 25.0). Landiolol resulted in a shorter hospital length-of-stay (LOS) (268 patients; mean difference, -2.32 days; 95% CI, -4.02 to -0.57; I2 = 0%). We found no significant difference in bradycardia (RR, 1.11; 95% CI, 0.48 to 2.56; I2 = 0%). No hypotension was reported with landiolol. We judged the certainty of evidence as moderate for POAF (because of indirectness as outcomes were not clearly defined) and low for LOS (because of imprecision and concern of reporting bias). CONCLUSION: In patients undergoing cardiac surgery, landiolol likely reduces POAF and may reduce LOS. A definitive large RCT is needed to confirm these findings. STUDY REGISTRATION: PROSPERO (CRD42021262703); registered 25 July 2021.

RéSUMé: OBJECTIF: La fibrillation auriculaire postopératoire (FAPO) est une complication fréquente après une chirurgie cardiaque. Bien que les données probantes suggèrent que les bêta-bloqueurs préviennent la FAPO, ces agents provoquent souvent une hypotension. Le landiolol, un ß1-bloqueur à action ultra-courte, pourrait prévenir la FAPO sans conséquences hémodynamiques indésirables. SOURCES: Nous avons effectué des recherches dans les bases de données MEDLINE, CENTRAL et Embase, et dans les registres d'études publiées entre janvier 1970 et mars 2022. Nous avons inclus les études randomisées contrôlées (ERC) évaluant l'effet du landiolol pour la prévention de la FAPO après une chirurgie cardiaque. Deux personnes ont indépendamment révisé l'éligibilité, extrait les données et évalué le risque de biais à l'aide de l'outil Risque de biais 2.0. Nous avons regroupé les données à l'aide de modèles à effets aléatoires. Nous avons utilisé le système de notation GRADE (Grading of Recommendations Assessment, Development, and Evaluation) pour évaluer la certitude des données probantes. CONSTATATIONS PRINCIPALES: Neuf ERC incluant 868 personnes remplissaient les critères d'éligibilité. Les patient·es randomisé·es dans le groupe landiolol (56/460) présentaient moins de FAPO que les témoins (133/408), avec un risque relatif (RR) de 0,40 (intervalle de confiance [IC] à 95 %, 0,30 à 0,54; I2 = 0 %) et un risque absolu de 12,2 % vs 32,6 % (différence de risque absolue, 20,4 %; IC 95 % 95 %, 15,0 à 25,0). Le landiolol a entraîné une durée de séjour hospitalier plus courte (268 patient·es; différence moyenne, −2,32 jours; IC 95 %, −4,02 à −0,57; I2 = 0 %). Nous n'avons trouvé aucune différence significative en matière de bradycardie (RR, 1,11; IC 95 %, 0,48 à 2,56; I2 = 0 %). Aucune hypotension n'a été rapportée avec le landiolol. Nous avons jugé que la certitude des données probantes était modérée pour la FAPO (en raison du caractère indirect car les critères d'évaluation n'étaient pas clairement définis) et faible pour la durée de séjour hospitalier (en raison de l'imprécision et de questionnements concernant le biais de déclaration). CONCLUSION: Chez les patient·es bénéficiant d'une chirurgie cardiaque, le landiolol réduit probablement la FAPO et peut réduire la durée de séjour hospitalier. Une ERC définitive à grande échelle est nécessaire pour confirmer ces résultats. ENREGISTREMENT DE L'éTUDE: PROSPERO (CRD42021262703); enregistrée le 25 juillet 2021.

Risk Scores for Prediction of Postoperative Atrial Fibrillation After Cardiac Surgery: A Systematic Review and Meta-Analysis.

Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery and is associated with poor clinical outcomes. The objective of this systematic review and meta-analysis was to assess the performance of risk scores to predict POAF in cardiac surgery patients. We searched MEDLINE, Embase, and Cochrane CENTRAL for studies that developed/evaluated a POAF risk prediction model. Pairs of reviewers independently screened studies and extracted data. We pooled area under the receiver operating curves (AUCs), sensitivity and specificity, and adjusted odds ratios from multivariable regression analyses using the generic inverse variance method and random effects models. Forty-three studies (n = 63,847) were included in the quantitative synthesis. Most scores were originally developed for other purposes but evaluated for predicting POAF. Pooled AUC revealed moderate POAF discrimination for the EuroSCORE II (AUC 0.59, 95% confidence interval [CI] 0.54 to 0.65), Society of Thoracic Surgeons (AUC 0.60, 95% CI 0.56 to 0.63), EuroSCORE (AUC 0.63, 95% CI 0.58 to 0.68), CHADS2 (AUC 0.66, 95% CI 0.57 to 0.75), POAF Score (AUC 0.66, 95% CI 0.63 to 0.68), HATCH (AUC 0.67, 95% CI 0.57 to 0.75), CHA2DS2-VASc (AUC 0.68, 95% CI 0.60 to 0.75) and SYNTAX scores (AUC 0.74, 95% CI 0.71 to 0.78). Pooled analyses at specific cutoffs of the CHA2DS2-VASc, CHADS2, HATCH, and POAF scores demonstrated moderate-to-high sensitivity (range 46% to 87%) and low-to-moderate specificity (range 31% to 70%) for POAF prediction. In conclusion, existing clinical risk scores offer at best moderate prediction for POAF after cardiac surgery. Better models are needed to guide POAF risk stratification in cardiac surgery patients.

Atrial Fibrillation Recurrence in Patients With Transient New-Onset Atrial Fibrillation Detected During Hospitalization for Noncardiac Surgery or Medical Illness : A Matched Cohort Study.

BACKGROUND: Atrial fibrillation (AF) is often detected for the first time in patients who are hospitalized for another reason. Long-term risks for AF recurrence in these patients are unclear. OBJECTIVE: To estimate risk for AF recurrence in patients with new-onset AF during a hospitalization for noncardiac surgery or medical illness compared with a matched population without AF. DESIGN: Matched cohort study. (ClinicalTrials.gov: NCT03221777). SETTING: Three academic hospitals in Hamilton, Ontario, Canada. PARTICIPANTS: The study enrolled patients hospitalized for noncardiac surgery or medical illness who had transient new-onset AF. For each participant, an age- and sex-matched control participant with no history of AF from the same hospital ward was recruited. All participants left the hospital in sinus rhythm. MEASUREMENTS: 14-day electrocardiographic (ECG) monitor at 1 and 6 months and telephone assessment at 1, 6, and 12 months. The primary outcome was AF lasting at least 30 seconds on the monitor or captured by ECG 12-lead during routine care at 12 months. RESULTS: Among 139 participants with transient new-onset AF (70 patients with medical illness and 69 surgical patients) and 139 matched control participants, the mean age was 71 years (SD, 10), the mean CHA2DS2-VASc score was 3.0 (SD, 1.5), and 59% were male. The median duration of AF during the index hospitalization was 15.8 hours (IQR, 6.4 to 49.6 hours). After 1 year, recurrent AF was detected in 33.1% (95% CI, 25.3% to 40.9%) of participants in the transient new-onset AF group and 5.0% (CI, 1.4% to 8.7%) of matched control participants; after adjustment for the number of ECG monitors worn and for baseline clinical differences, the adjusted relative risk was 6.6 (CI, 3.2 to 13.7). After exclusion of participants who had electrical or pharmacologic cardioversion during the index hospitalization (n = 40) and their matched control participants and limiting to AF events detected by the patch ECG monitor, recurrent AF was detected in 32.3% (CI, 23.1% to 41.5%) of participants with transient new-onset AF and 3.0% (CI, 0% to 6.4%) of matched control participants. LIMITATIONS: Generalizability is limited, and the study was underpowered to evaluate subgroups and clinical predictors. CONCLUSION: Among patients who have transient new-onset AF during a hospitalization for noncardiac surgery or medical illness, approximately 1 in 3 will have recurrent AF within 1 year. PRIMARY FUNDING SOURCE: Peer-reviewed grants.

Oral Anticoagulation Use and Left Atrial Appendage Occlusion in LAAOS III.

BACKGROUND: LAAOS III (Left Atrial Appendage Occlusion Study III) showed that left atrial appendage (LAA) occlusion reduces the risk of ischemic stroke or systemic embolism in patients with atrial fibrillation undergoing cardiac surgery. This article examines the effect of LAA occlusion on stroke reduction according to variation in the use of oral anticoagulant (OAC) therapy. METHODS: Information regarding OAC use was collected at every follow-up visit. Adjusted proportional hazards modeling, including using landmarks of hospital discharge, 1 and 2 years after randomization, evaluated the effect of LAA occlusion on the risk of ischemic stroke or systemic embolism, according to OAC use. Adjusted proportional hazard modeling, with OAC use as a time-dependent covariate, was also performed to assess the effect of LAA occlusion, according to OAC use throughout the study. RESULTS: At hospital discharge, 3027 patients (63.5%) were receiving a vitamin K antagonist, and 879 (18.5%) were receiving a non-vitamin K antagonist oral anticoagulant (direct OAC), with no difference in OAC use between treatment arms. There were 2887 (60.5%) patients who received OACs at all follow-up visits, 1401 (29.4%) who received OAC at some visits, and 472 (9.9%) who never received OACs. The effect of LAA occlusion on the risk of ischemic stroke or systemic embolism was consistent after discharge across all 3 groups: hazard ratios of 0.70 (95% CI, 0.51-0.96), 0.63 (95% CI, 0.43-0.94), and 0.76 (95% CI, 0.32-1.79), respectively. An adjusted proportional hazards model with OAC use as a time-dependent covariate showed that the reduction in stroke or systemic embolism with LAA occlusion was similar whether patients were receiving OACs or not. CONCLUSIONS: The benefit of LAA occlusion was consistent whether patients were receiving OACs or not. LAA occlusion provides thromboembolism reduction in patients independent of OAC use.

Rhythm vs. Rate Control in Patients with Postoperative Atrial Fibrillation after Cardiac Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery; it is associated with morbidity and mortality. We undertook this review to compare the effects of rhythm vs. rate control in this population. METHODS: We searched MEDLINE, Embase and CENTRAL to March 2023. We included randomized trials and observational studies comparing rhythm to rate control in cardiac surgery patients with POAF. We used a random-effects model to meta-analyze data and rated the quality of evidence using GRADE. RESULTS: From 8,110 citations, we identified 8 randomized trials (990 patients). Drug regimens used for rhythm control included amiodarone in four trials, other class III anti-arrhythmics in one trial, class I anti-arrhythmics in four trials and either a class I or III anti-arrhythmic in one trial. Rhythm control compared to rate control did not result in a significant difference in length of stay (mean difference -0.8 days; 95% CI -3.0 to +1.4, I2 = 97%), AF recurrence within 1 week (130 events; risk ratio [RR] 1.1; 95%CI 0.6-1.9, I2 = 54%), AF recurrence up to 1 month (37 events; RR 0.9; 95%CI 0.5-1.8, I2 = 0%), AF recurrence up to 3 months (10 events; RR 1.0; 95%CI 0.3-3.4, I2 = 0%) or mortality (25 events; RR 1.6; 95%CI 0.7-3.5, I2 = 0%). Effect measures from seven observational studies (1428 patients) did not differ appreciably from those in randomized trials. CONCLUSIONS: Although atrial fibrillation is common after cardiac surgery, limited low-quality data guide its management. Limited available evidence suggests no clear advantage to either rhythm or rate control. A large-scale randomized trial is needed to inform this important clinical question.

Cost Implications of Left Atrial Appendage Occlusion During Cardiac Surgery: A Cost Analysis of the LAAOS III Trial.

Background The LAAOS III (Left Atrial Appendage Occlusion Study) clinical trial demonstrated that concomitant left atrial appendage (LAA) occlusion leads to a lower risk of ischemic stroke or systemic embolism compared with no occlusion in participants with atrial fibrillation and a CHA2DS2-VASc score of ≥2 undergoing cardiac surgery for another indication. We report the cost implications of concomitant LAA occlusion during cardiac surgery. Methods and Results Using LAAOS III data, we compared the costs (in US dollars) associated with LAA occlusion to no occlusion from the perspective of the Centers for Medicare and Medicaid Services. We calculated the average cost per participant during the trial by applying Medicare reimbursement costs to cardiovascular events for all trial participants. We conducted sensitivity analyses, varying the cost of stroke ±25% and occlusion technique use. Cost neutrality was defined as a mean cost difference within ±5% of the cost per participant in the no-occlusion group. Total study cost per participant was $3878 in the LAA occlusion group and $4490 in the no-occlusion group, a mean difference of -$612 (95% CI, -$1276 to $45). The main drivers of cost savings were fewer stroke events during the trial (mean difference of -$1021). In sensitivity analyses, LAA occlusion was cost saving for suture and stapler techniques but more expensive with closure device. Conclusions Concomitant LAA occlusion was cost saving for participants in LAAOS III. Our findings support concomitant LAA occlusion as an economically dominant strategy for patients with atrial fibrillation and a CHA2DS2-VASc score of ≥2 undergoing cardiac surgery.

Hypotension-Avoidance Versus Hypertension-Avoidance Strategies in Noncardiac Surgery : An International Randomized Controlled Trial.

BACKGROUND: Among patients having noncardiac surgery, perioperative hemodynamic abnormalities are associated with vascular complications. Uncertainty remains about what intraoperative blood pressure to target and how to manage long-term antihypertensive medications perioperatively. OBJECTIVE: To compare the effects of a hypotension-avoidance and a hypertension-avoidance strategy on major vascular complications after noncardiac surgery. DESIGN: Partial factorial randomized trial of 2 perioperative blood pressure management strategies (reported here) and tranexamic acid versus placebo. (ClinicalTrials.gov: NCT03505723). SETTING: 110 hospitals in 22 countries. PATIENTS: 7490 patients having noncardiac surgery who were at risk for vascular complications and were receiving 1 or more long-term antihypertensive medications. INTERVENTION: In the hypotension-avoidance strategy group, the intraoperative mean arterial pressure target was 80 mm Hg or greater; before and for 2 days after surgery, renin-angiotensin-aldosterone system inhibitors were withheld and the other long-term antihypertensive medications were administered only for systolic blood pressures 130 mm Hg or greater, following an algorithm. In the hypertension-avoidance strategy group, the intraoperative mean arterial pressure target was 60 mm Hg or greater; all antihypertensive medications were continued before and after surgery. MEASUREMENTS: The primary outcome was a composite of vascular death and nonfatal myocardial injury after noncardiac surgery, stroke, and cardiac arrest at 30 days. Outcome adjudicators were masked to treatment assignment. RESULTS: The primary outcome occurred in 520 of 3742 patients (13.9%) in the hypotension-avoidance group and in 524 of 3748 patients (14.0%) in the hypertension-avoidance group (hazard ratio, 0.99 [95% CI, 0.88 to 1.12]; P = 0.92). Results were consistent for patients who used 1 or more than 1 antihypertensive medication in the long term. LIMITATION: Adherence to the assigned strategies was suboptimal; however, results were consistent across different adherence levels. CONCLUSION: In patients having noncardiac surgery, our hypotension-avoidance and hypertension-avoidance strategies resulted in a similar incidence of major vascular complications. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research, National Health and Medical Research Council (Australia), and Research Grant Council of Hong Kong.

Direct oral anticoagulants versus vitamin K antagonists in the first 3 months after bioprosthetic valve replacement: a systematic review and meta-analysis.

OBJECTIVES: We conducted a systematic review and meta-analysis of randomized controlled trials comparing direct oral anticoagulants (DOACs) to vitamin K antagonists (VKAs) in the first 90 days after bioprosthetic valve implantation. METHODS: We systematically searched Embase, Medline and CENTRAL. We screened titles, abstracts and full texts, extracted data and assessed the risk of bias in duplicate. We pooled data using the Mantel-Haenzel method and random effects modelling. We conducted subgroup analyses based on the type of valve (transcatheter versus surgical) and timing of initiation of anticoagulation (<7 vs >7 days after valve implantation). We assessed the certainty of evidence using the Grading of Recommendations, Assessments, Development and Evaluation approach. RESULTS: We included 4 studies of 2284 patients with a median follow-up of 12 months. Two studies examined transcatheter valves (1877/2284 = 83%) and 2 examined surgical valves (407/2284 = 17%). We found no statistically significant differences between DOACs and VKAs with regard to thrombosis, bleeding, death or subclinical valve thrombosis. However, there was a subgroup trend towards more bleeding with DOACs when initiated within 7 days of valve implantation. CONCLUSIONS: In the existing randomized literature on DOACs versus VKAs in the first 90 days after bioprosthetic valve implantation, there appears to be no difference with regard to thrombosis, bleeding or death. Interpretation of the data is limited by small numbers of events and wide confidence intervals. Future studies should focus on surgical valves and should include long-term follow-up to assess any potential impact of randomized therapy on valve durability.

How Did We Get Here? Antithrombotic Therapy after Bioprosthetic Aortic Valve Replacement: A Review.

IMPORTANCE: Aortic stenosis is the most common valvular disease, and more than 90% of patients who undergo aortic valve replacement receive a bioprosthetic valve. Yet optimal antithrombotic therapy after bioprosthetic aortic valve replacement remains uncertain, and guidelines provide contradictory recommendations. OBSERVATIONS: Randomized studies of antithrombotic therapy after bioprosthetic aortic valve replacement are small and underpowered. Observational data present opposing, and likely confounded, results. Historically, changes to guidelines have not been informed by high-quality new data. Current guidelines from different professional bodies provide contradictory recommendations despite citing the same evidence. CONCLUSION: Insufficient antithrombotic therapy after bioprosthetic aortic valve replacement has serious implications: ischemic stroke, systemic arterial thromboembolism, and clinical and subclinical valve thromboses. Unnecessarily intense antithrombotic therapy, however, increases risk of bleeding and associated morbidity and mortality. Professional bodies have used the current low-quality evidence and generated incongruent recommendations. Researchers should prioritize generating high-quality, randomized evidence evaluating the risks and benefits of antiplatelet versus anticoagulant therapy after bioprosthetic aortic valve replacement.

Colchicine and aspirin in community patients with COVID-19 (ACT): an open-label, factorial, randomised, controlled trial.

BACKGROUND: The large number of patients worldwide infected with the SARS-CoV-2 virus has overwhelmed health-care systems globally. The Anti-Coronavirus Therapies (ACT) outpatient trial aimed to evaluate anti-inflammatory therapy with colchicine and antithrombotic therapy with aspirin for prevention of disease progression in community patients with COVID-19. METHODS: The ACT outpatient, open-label, 2 × 2 factorial, randomised, controlled trial, was done at 48 clinical sites in 11 countries. Patients in the community aged 30 years and older with symptomatic, laboratory confirmed COVID-19 who were within 7 days of diagnosis and at high risk of disease progression were randomly assigned (1:1) to receive colchicine 0·6 mg twice daily for 3 days and then 0·6 mg once daily for 25 days versus usual care, and in a second (1:1) randomisation to receive aspirin 100 mg once daily for 28 days versus usual care. Investigators and patients were not masked to treatment allocation. The primary outcome was assessed at 45 days in the intention-to-treat population; for the colchicine randomisation it was hospitalisation or death, and for the aspirin randomisation it was major thrombosis, hospitalisation, or death. The ACT outpatient trial is registered at ClinicalTrials.gov, NCT04324463 and is ongoing. FINDINGS: Between Aug 27, 2020, and Feb 10, 2022, 3917 patients were randomly assigned to colchicine or control and to aspirin or control; after excluding 36 patients due to administrative reasons 3881 individuals were included in the analysis (n=1939 colchicine vs n=1942 control; n=1945 aspirin vs 1936 control). Follow-up was more than 99% complete. Overall event rates were 5 (0·1%) of 3881 for major thrombosis, 123 (3·2%) of 3881 for hospitalisation, and 23 (0·6%) of 3881 for death; 66 (3·4%) of 1939 patients allocated to colchicine and 65 (3·3%) of 1942 patients allocated to control experienced hospitalisation or death (hazard ratio [HR] 1·02, 95% CI 0·72-1·43, p=0·93); and 59 (3·0%) of 1945 of patients allocated to aspirin and 73 (3·8%) of 1936 patients allocated to control experienced major thrombosis, hospitalisation, or death (HR 0·80, 95% CI 0·57-1·13, p=0·21). Results for the primary outcome were consistent in all prespecified subgroups, including according to baseline vaccination status, timing of randomisation in relation to onset of symptoms (post-hoc analysis), and timing of enrolment according to the phase of the pandemic (post-hoc analysis). There were more serious adverse events with colchicine than with control (34 patients [1·8%] of 1939 vs 27 [1·4%] of 1942) but none in either group that led to discontinuation of study interventions. There was no increase in serious adverse events with aspirin versus control (31 [1·6%] vs 31 [1·6%]) and none that led to discontinuation of study interventions. INTERPRETATION: The results provide no support for the use of colchicine or aspirin to prevent disease progression or death in outpatients with COVID-19. FUNDING: Canadian Institutes for Health Research, Bayer, Population Health Research Institute, Hamilton Health Sciences Research Institute, and Thistledown Foundation. TRANSLATIONS: For the Portuguese, Russian and Spanish translations of the abstract see Supplementary Materials section.

Colchicine and the combination of rivaroxaban and aspirin in patients hospitalised with COVID-19 (ACT): an open-label, factorial, randomised, controlled trial.

BACKGROUND: COVID-19 disease is accompanied by a dysregulated immune response and hypercoagulability. The Anti-Coronavirus Therapies (ACT) inpatient trial aimed to evaluate anti-inflammatory therapy with colchicine and antithrombotic therapy with the combination of rivaroxaban and aspirin for prevention of disease progression in patients hospitalised with COVID-19. METHODS: The ACT inpatient, open-label, 2 × 2 factorial, randomised, controlled trial was done at 62 clinical centres in 11 countries. Patients aged at least 18 years with symptomatic, laboratory confirmed COVID-19 who were within 72 h of hospitalisation or worsening clinically if already hospitalised were randomly assigned (1:1) to receive colchicine 1·2 mg followed by 0·6 mg 2 h later and then 0·6 mg twice daily for 28 days versus usual care; and in a second (1:1) randomisation, to the combination of rivaroxaban 2·5 mg twice daily plus aspirin 100 mg once daily for 28 days versus usual care. Investigators and patients were not masked to treatment allocation. The primary outcome, assessed at 45 days in the intention-to-treat population, for the colchicine randomisation was the composite of the need for high-flow oxygen, mechanical ventilation, or death; and for the rivaroxaban plus aspirin randomisation was the composite of major thrombosis (myocardial infarction, stroke, acute limb ischaemia, or pulmonary embolism), the need for high-flow oxygen, mechanical ventilation, or death. The trial is registered at www. CLINICALTRIALS: gov, NCT04324463 and is ongoing. FINDINGS: Between Oct 2, 2020, and Feb 10, 2022, at 62 sites in 11 countries, 2749 patients were randomly assigned to colchicine or control and the combination of rivaroxaban and aspirin or to the control. 2611 patients were included in the analysis of colchicine (n=1304) versus control (n=1307); 2119 patients were included in the analysis of rivaroxaban and aspirin (n=1063) versus control (n=1056). Follow-up was more than 98% complete. Overall, 368 (28·2%) of 1304 patients allocated to colchicine and 356 (27·2%) of 1307 allocated to control had a primary outcome (hazard ratio [HR] 1·04, 95% CI 0·90-1·21, p=0·58); and 281 (26·4%) of 1063 patients allocated to the combination of rivaroxaban and aspirin and 300 (28·4%) of 1056 allocated to control had a primary outcome (HR 0·92, 95% CI 0·78-1·09, p=0·32). Results were consistent in subgroups defined by vaccination status, disease severity at baseline, and timing of randomisation in relation to onset of symptoms. There was no increase in the number of patients who had at least one serious adverse event for colchicine versus control groups (87 [6·7%] of 1304 vs 90 [6·9%] of 1307) or with rivaroxaban and aspirin versus control groups (85 [8·0%] vs 91 [8·6%]). Among patients assigned to colchicine, 8 (0·61%) had adverse events that led to discontinuation of study drug, mostly gastrointestinal in nature. 17 (1·6%) patients assigned to the combination of rivaroxaban and aspirin had bleeding compared with seven (0·66%) of those allocated to control (p=0·042); the number of serious bleeding events was two (0·19%) versus six (0·57%), respectively (p=0·18). No patients assigned to rivaroxaban and aspirin had serious adverse events that led to discontinuation of study drug. INTERPRETATION: Among patients hospitalised with COVID-19, neither colchicine nor the combination of rivaroxaban and aspirin prevent disease progression or death. FUNDING: Canadian Institutes for Health Research, Bayer, Population Health Research Institute, Hamilton Health Sciences Research Institute, Thistledown Foundation. TRANSLATIONS: For the Portuguese, Russian and Spanish translations of the abstract see Supplementary Materials section.