Antithrombotic therapy after mitral valve repair: VKA or aspirin?

Efficacy and safety of anti-thrombotic therapy after surgical mitral valve repair: a scoping review

BACKGROUND

Mitral valve repair (MVr) is the gold standard treatment for degenerative mitral regurgitation, yet there is ongoing controversy regarding optimal anti-thrombotic therapy post-MVr. This scoping review aimed to summarise current evidence on the safety and efficacy of anti-thrombotic therapy after MVr, identify knowledge gaps and propose a future study design.

METHODS

We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, the WHO International Clinical Trials Registry Platform and bibliographies of included trials, guidelines and other reviews from inception to 17 September 2024. Randomised controlled trials (RCT) and cohort and case-control studies assessing any anti-thrombotic therapy with any outcomes after MVr were included. Using a predefined collection form, two authors independently extracted data on study characteristics and results were summarised narratively into themes based on the PICO elements.

RESULTS

Of 1296 screened references, we included 11 studies (10 cohort and one non-inferiority RCT). All studies compared vitamin K antagonist (VKA) to an anti-platelet, direct oral anti-coagulant or no anti-thrombotic therapy for median duration of 90 days. Thromboembolic and bleeding event incidences ranged from 0% to 14.3% and 0% to 9.1%, respectively. Seven studies reported no difference in thromboembolic events, and three reported reduced rates with VKA compared with control, while results for bleeding events varied widely. The RCT found edoxaban was non-inferior to warfarin for thromboembolic outcomes, but not for bleeding. Substantial methodological and clinical heterogeneity, high risk of bias and insufficient mitigation of confounders, such as concomitant atrial fibrillation, were prevalent across studies.

CONCLUSION

Based on this scoping review, existing literature on anti-thrombotic therapy after MVr is inconclusive due to design limitations. We proposed a study design for a pragmatic RCT that addresses prior study limitations and that could provide definitive evidence to guide anti-thrombotic management in MVr patients.

Antithrombotic therapy after heart valve surgery: contemporary practice in the UK

OBJECTIVES

There is a lack of high-quality data informing the optimal antithrombotic drug strategy following bioprosthetic heart valve replacement or valve repair. Disparity in recommendations from international guidelines reflects this. This study aimed to document current patterns of antithrombotic prescribing after heart valve surgery in the UK.

METHODS

All UK consultant cardiac surgeons were e-mailed a custom-designed survey. The use of oral anticoagulant (OAC) and/or antiplatelet drugs following bioprosthetic aortic valve replacement or mitral valve replacement, or mitral valve repair (MVrep), for patients in sinus rhythm, without additional indications for antithrombotic medication, was assessed. Additionally, we evaluated anticoagulant choice following MVrep in patients with atrial fibrillation.

RESULTS

We identified 260 UK consultant cardiac surgeons from 36 units, of whom 103 (40%) responded, with 33 units (92%) having at least 1 respondent. The greatest consensus was for patients undergoing bioprosthetic aortic valve replacement, in which 76% of surgeons favour initial antiplatelet therapy and 53% prescribe lifelong treatment. Only 8% recommend initial OAC. After bioprosthetic mitral valve replacement, 48% of surgeons use an initial OAC strategy (versus 42% antiplatelet), with 66% subsequently prescribing lifelong antiplatelet therapy. After MVrep, recommendations were lifelong antiplatelet agent alone (34%) or following 3 months OAC (20%), no antithrombotic agent (20%), or 3 months OAC (16%). After MVrep for patients with established atrial fibrillation, surgeons recommend warfarin (38%), a direct oral anticoagulant (37%) or have no preference between the 2 (25%).

CONCLUSIONS

There is considerable variation in the use of antithrombotic drugs after heart valve surgery in the UK and a lack of high-quality evidence to guide practice, underscoring the need for randomized studies.

Antithrombotic Treatment After Transcatheter Valve Interventions: Current Status and Future Directions

PURPOSE

The optimal antithrombotic strategy after transcatheter valve interventions is a subject of ongoing debate. Although there is evidence from randomized trials in patients undergoing transcatheter aortic valve replacement (TAVR), current evidence on optimal antithrombotic management after transcatheter mitral or tricuspid valve interventions is sparse. This article appraises the current evidence on this topic.

METHODS

This narrative review presents key research findings and guideline recommendations, as well as highlights areas for future research.

FINDINGS

After TAVR, randomized trial evidence suggests that single antiplatelet therapy is reasonable for patients without pre-existing indications for oral anticoagulation (OAC). If there is a concurrent indication for OAC, the addition of antiplatelet therapy increases bleeding risk. Whether direct oral anticoagulants achieve better outcomes than vitamin K antagonists is uncertain in this setting. Although OAC has been shown to reduce subclinical leaflet thrombosis (which may progress to structural valve degeneration), bleeding events are unacceptably high. There is a lack of randomized trial data comparing antithrombotic strategies after transcatheter mitral or tricuspid valve replacement or after mitral or tricuspid transcatheter edge-to-edge repair. Single antiplatelet therapy after mitral or tricuspid transcatheter edge-to-edge repair may be appropriate, whereas at least 3 months of OAC is suggested after transcatheter mitral valve replacement or transcatheter tricuspid valve replacement.

IMPLICATIONS

Randomized studies are warranted to address the knowledge gaps in antithrombotic therapy after transcatheter valve interventions and to optimize outcomes.

Oral Anticoagulation Versus Antiplatelet Treatment After Mitral Valve Repair: A Systematic Review and Meta-Analysis

Oral anticoagulation with vitamin K antagonists is currently advised for a period of 3 months after surgical mitral valve repair, regardless of the rhythm status. The evidence supporting this recommendation is weak and recent studies have challenged the safety and efficacy of this recommendation. A systematic review of literature was conducted by searching PubMed, Embase, Web of Science, Emcare, and Cochrane Library databases for original publications comparing the efficacy and safety of oral anticoagulation with vitamin K antagonists to antiplatelet treatment early after mitral valve surgery in patients with no atrial fibrillation. Study end points included thromboembolic complications, bleeding complications and survival. A total of 5 studies, including 5,093 patients, met the inclusion criteria; 2,824 patients were included in the oral anticoagulation and 2,269 in the antiplatelet treatment group. Pooled analyses demonstrated no beneficial effect of oral anticoagulation on the incidence of thromboembolic complications (risk ratio 1.14, 95% confidence interval 0.76 to 1.70, p = 0.53, I2 = 8%). Moreover, oral anticoagulation did not result in a significantly increased risk of bleeding complications (risk ratio 0.89, 95% confidence interval 0.32 to 2.44, p = 0.81, I2 = 87%). When combining the efficacy and safety end points, no difference was observed between groups (risk ratio 1.01, 95% confidence interval 0.51 to 1.97, p = 0.99 I2 = 85%). Likewise, mortality did not differ between groups (risk ratio 0.89, 95% confidence interval 0.15 to 5.23, p = 0.90 I2 = 71%). Our results confirmed the safety but failed to confirm the efficacy of oral anticoagulation in patients who underwent mitral valve surgery. A randomized controlled trial would provide the evidence needed to support treatment recommendations.

Risk of Stroke and Major Bleeding With Vitamin K Antagonist Use After Mitral Valve Repair

BACKGROUND

Guidelines are discordant on the use of a vitamin K antagonist (VKA) after mitral valve repair (MVr) to reduce the risk of cerebral embolic events. We performed an observational study among patients who underwent a MVr, without perioperative atrial fibrillation, to determine the risk of cerebral ischemic and major bleeding events with or without VKA.

METHODS

From 2004 to 2016, we included patients who underwent MVr, using a national administrative claims database. Those with preoperative atrial fibrillation and anticoagulant use were excluded. Patients were stratified based on the presence of a VKA. Inverse probability weighting with a Cox proportional hazard model was used.

RESULTS

After MVr, 754 patients were discharged on VKA and 1462 on no-VKA. We found no difference in the cumulative incidence for embolic stroke at 180 days (VKA: 2.21% vs no-VKA: 1.50%; hazard ratio, 1.35; P = .38). However, VKA patients had a significantly increased risk for any-cause major bleeding events at 180 days (VKA: 8.58% vs no-VKA: 4.21%; hazard ratio, 2.09; P < .001). VKA patients also had increased need for a pericardiocentesis/pericardial window at 30 days after discharge (VKA: 1.13% vs no-VKA: 0.37%; hazard ratio, 3.88; P = .025).

CONCLUSIONS

Our study suggests that VKA after MVr does not reduce the risk of cerebral embolic events but is associated with an increased risk of major bleeding events.

Apixaban for Anticoagulation After Robotic Mitral Valve Repair

BACKGROUND

There is no consensus regarding postoperative anticoagulation after mitral valve repair (MVRep). We compared the outcomes of post-MVRep anticoagulation with apixaban compared to warfarin.

METHODS

We reviewed data of 666 patients who underwent isolated robotic MVRep between January 2008 and October 2019. We excluded patients who had conversion to sternotomy and those discharged without anticoagulation or on clopidogrel (n = 40). Baseline and intraoperative characteristics and antiplatelet/anticoagulation records were collected. In-hospital and post-discharge complications and overall survival were compared.

RESULTS

Among the 626 studied patients the median age was 58 years (interquartile range, 51-66), 71% were male, and 1% (n = 9) had atrial fibrillation. Eighty percent (n = 499) were discharged on warfarin and 20% on apixaban (n = 127). Almost all patients (126 of 127, 99%) in the apixaban group were also on aspirin at discharge, whereas in the warfarin group only 79% (n = 395) were also on aspirin at discharge. Baseline characteristics were similar, except that the apixaban group had more female patients (46 of 127, 36% vs 136 of 499, 27%, P = .047). There were no differences in in-hospital complications, including stroke. Readmission rate was higher in the apixaban group (15 of 127, 12% vs 30 of 499, 6%, P = .02), driven mostly by postoperative atrial fibrillation (6 of 127 [5%] vs 5 of 499 [1%], respectively; P = .01). There was no difference in other complications (including bleeding and thromboembolic events), or overall mortality within 3 years. Exclusion of patients who did not receive aspirin at discharge did not affect the results.

CONCLUSIONS

Anticoagulation with apixaban after minimally invasive robotic MVRep is safe and has similar rates of bleeding and thromboembolism compared to patients treated with warfarin.

Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation and Valve Replacement or Repair

Background We sought to examine outcomes of direct oral anticoagulants (DOACs) versus warfarin in atrial fibrillation with valve repair/replacement. Methods and Results Two atrial fibrillation cohorts from Medicare were identified from 2015 to 2019. They comprised patients who underwent surgical or transcatheter mitral valve repair (MV repair cohort) and surgical aortic or mitral bioprosthetic or transcatheter aortic valve replacement (bioprosthetic cohort). Each cohort was divided into warfarin and DOACs (apixaban, rivaroxaban, and dabigatran) groups. Study outcomes included mortality, stroke, and major bleeding. Inverse probability weighting was used for adjustment between the 2 groups in each cohort. The MV repair cohort included 1178 patients. After a median of 468 days, DOACs were associated with lower risk of mortality (hazard ratio [HR], 0.67 [95% CI, 0.55-0.82], P<0.001), ischemic stroke (HR, 0.72 [95% CI, 0.52-1.00], P=0.05) and bleeding (HR, 0.79 [95% CI, 0.63-0.99], P=0.04) compared with warfarin. The bioprosthetic cohort included 8089 patients. After a median follow-up of 413 days, DOACs were associated with similar risk of mortality (adjusted HR, 0.93 [95% CI, 0.86-1.01], P=0.08), higher risk of ischemic stroke (adjusted HR, 1.27 [95% CI, 1.13-1.43], P<0.001), and lower risk of bleeding (adjusted HR, 0.86 [95% CI, 0.80-0.93], P<0.001) compared with warfarin. Conclusions In patients with atrial fibrillation, DOACs are associated with similar mortality, lower bleeding, but higher stroke with bioprosthetic valve replacement and lower risk of all 3 outcomes with MV repair compared with warfarin.

At the Crossroads of Minimally Invasive Mitral Valve Surgery—Benching Single Hospital Experience to a National Registry: A Plea for Risk Management Technology

Almost 30 years after the first endoscopic mitral valve repair, Minimally Invasive Mitral Valve Surgery (MIMVS) has become the standard at many institutions due to optimal clinical results and fast recovery. The question that arises is can already good results be further improved by an Institutional Risk Management Performance (IRMP) system in decreasing risks in minimally invasive mitral valve surgery (MIMVS)? As of yet, there are no reports on IRMP and learning systems in the literature. (2) Methods: We described and appraised our five-year single institutional experience with MIMVS in isolated valve surgery included in the Netherlands Heart Registry (NHR) and investigated root causes of high-impact complications. (3) Results: The 120-day and 12-month mortality were 1.1% and 1.9%, respectively, compared to the average of 4.3% and 5.3% reported in the NHR. The regurgitation rate was 1.4% compared to 5.2% nationwide. The few high-impact complications appeared not to be preventable. (4) Discussion: In MIMVS, freedom from major and minor complications is a strong indicator of an effective IRMP but remains concealed from physicians and patients, despite its relevance to shared decision making. Innovation adds to the complexity of MIMVS and challenges surgical competence. An IRMP system may detect and control new risks earlier. (5) Conclusion: An IRMP system contributes to an effective reduction of risks, pain and discomfort; provides relevant input for shared decision making; and warrants the safe introduction of new technology. Crossroads conclusions: investment in machine learning and AI for an effective IRMP system is recommended and the roles for commanding and operating surgeons should be considered.

Antithrombotic Treatment After Surgical and Transcatheter Heart Valve Repair and Replacement

New antithrombotic drugs have been developed, new valve types have been designed and minimally invasive transcatheter techniques have emerged, making the choice of antithrombotic therapy after surgical or transcatheter heart valve repair and replacement increasingly complex. Moreover, due to a lack of large randomized controlled trials many recommendations for antithrombotic therapy are based on expert opinion, reflected by divergent recommendations in current guidelines. Therefore, decision-making in clinical practice regarding antithrombotic therapy for prosthetic heart valves is difficult, potentially resulting in sub-optimal patient treatment. This article compares the 2017 ESC/EACTS and 2020 ACC/AHA guidelines on the management of valvular heart disease and summarizes the available evidence. Finally, we established a convenient consensus on antithrombotic therapy after valve interventions based on over 800 annual cases of surgical and transcatheter heart valve repair and replacement and a multidisciplinary team discussion between the department of cardiovascular diseases and cardiac surgery of the University Hospitals Leuven, Belgium.

Anticoagulation and antiplatelet therapy in patients with prosthetic heart valves

BACKGROUND

The choice of antithrombotic therapy, anticoagulants or antiplatelets, after prosthetic heart valve replacement or repair, remains a disputed topic in the literature. Antithrombotic therapies are used after heart valve intervention to reduce the rates of thromboembolic events, therefore improving patient outcomes. Different interventions may require different therapeutic regimens to achieve the most efficacious clinical outcome for patients.

METHODS AND DISCUSSION

This review aims to summarize and critique the available literature concerning therapeutic agents used for bioprosthetic and mechanical valves as well as for valve repair, so as to assist clinicians and researchers in making decisions with regard to their patients and research endeavors.