Antithrombotic strategies after interventional left atrial appendage closure: an update

Antithrombotic Therapy for Patients Undergoing Cardiac Electrophysiological and Interventional Procedures: JACC State-of-the-Art Review

Electrophysiological and interventional procedures have been increasingly used to reduce morbidity and mortality in patients experiencing cardiovascular diseases. Although antithrombotic therapies are critical to reduce the risk of stroke or other thromboembolic events, they can nonetheless increase the bleeding hazard. This is even more true in an aging population undergoing cardiac procedures in which the combination of oral anticoagulants and antiplatelet therapies would further increase the hemorrhagic risk. Hence, the timing, dose, and combination of antithrombotic therapies should be carefully chosen in each case. However, the maze of society guidelines and consensus documents published so far have progressively led to a hazier scenario in this setting. Aim of this review is to provide-in a single document-a quick, evidenced-based practical summary of the antithrombotic approaches used in different cardiac electrophysiology and interventional procedures to guide the busy clinician and the cardiac proceduralist in their everyday practice.

Dual Antiplatelet Therapy and Cancer; Balancing between Ischemic and Bleeding Risk: A Narrative Review

Cardiovascular (CV) events in patients with cancer can be caused by concomitant CV risk factors, cancer itself, and anticancer therapy. Since malignancy can dysregulate the hemostatic system, predisposing cancer patients to both thrombosis and hemorrhage, the administration of dual antiplatelet therapy (DAPT) to patients with cancer who suffer from acute coronary syndrome (ACS) or undergo percutaneous coronary intervention (PCI) is a clinical challenge to cardiologists. Apart from PCI and ACS, other structural interventions, such as TAVR, PFO-ASD closure, and LAA occlusion, and non-cardiac diseases, such as PAD and CVAs, may require DAPT. The aim of the present review is to review the current literature on the optimal antiplatelet therapy and duration of DAPT for oncologic patients, in order to reduce both the ischemic and bleeding risk in this high-risk population.

Looking for optimal antithrombotic strategy after transcatheter left atrial appendage occlusion: a real-world comparison of different antiplatelet regimens

BACKGROUND

Transcatheter left atrial appendage occlusion (LAAO) has emerged as an effective procedure for the prevention of thromboembolic events in non-valvular atrial fibrillation (AF) patients with contraindications to oral anticoagulation. After the procedure, different antithrombotic regimens have been used, in order to prevent device-related thrombus and trying to minimize bleedings. The search for the optimal antithrombotic strategy is still ongoing. We sought to assess efficacy and safety of different antiplatelet therapy (APT) regimens.

METHODS

We enrolled non-randomized consecutive patients who underwent LAAO at the University Hospital of Parma between 2010 and 2021. Three study groups were identified according to post-procedural APT: long (>1, ≤12 months)-dual APT (DAPT), short (≤ 1 month)-DAPT, lifelong single APT (SAPT). The choice of the APT was left to multidisciplinary team evaluation. The incidence of the primary outcome, a composite of any ischemic or hemorrhagic event, was assessed at follow-up.

RESULTS

We enrolled a total of 130 patients. Technical success was achieved in 123 (94.6%) patients. After LAAO, 39 [31.7%] patients were discharged on short-DAPT, 35 [28.5%] on long-DAPT and 49 [39.8%] on SAPT. After a median follow-up of 32 months, short-DAPT group had a significantly lower occurrence of the primary outcome (3 [7.7%] vs. 7 [20.0%] in long-DAPT vs. 14 [28.6%] in SAPT, p = 0.049], mainly driven by a lower occurrence of the bleeding endpoint (0 vs. 4 [11.4%] in long-DAPT vs. 9 [18.4%] in SAPT, p = 0.020). Finally, comparison of the Kaplan-Meier curves showed that short-DAPT group had a higher primary endpoint-free survival [p = 0.015] compared to the other groups.

CONCLUSION

Post-procedural short-DAPT strategy was associated with better outcomes, mainly driven by reduction of major bleedings.

Risk of device-related thrombosis following short-term oral anticoagulation with low-dose dabigatran versus warfarin after Watchman left atrial appendage occlusion

BACKGROUND

Percutaneous left atrial appendage occlusion (LAAO) provides an alternative for poor candidates for long-term oral anticoagulation (OAC). To prevent device-related thrombosis (DRT), OAC should be continued for the first 45 days to allow complete endothelialization post-LAAO implantation. Whereas, evidence is limited on the feasibility and safety of direct oral anticoagulants (DOACs) used after LAAO.

METHODS

This was a retrospective observational single-center study of AF patients undergoing LAAO with a Watchman device and receiving either low-dose dabigatran (110mg twice daily) or warfarin in the peri- and post-procedural period for 45 days. Transesophageal echocardiography was scheduled to perform at 6 weeks, 6 months, and 12 months after the procedure to assess the stability of the device and to detect DRT. Incidence of thromboembolic and bleeding events were also evaluated during the follow-up period.

RESULTS

There were a total of 84 patients who successfully underwent Watchman implantation, with 38 patients (45.2%) receiving low-dose dabigatran and 46 patients (54.8%) using warfarin post-LAAO. Peri-procedural complications occurred in 10 patients, with 3 patients in the dabigatran group and 7 patients in the warfarin group (7.9% vs. 15.2%, p = 0.30). During the 12-month follow-up, 1 patient experienced major bleeding and 16 patients suffered minor bleeding in the warfarin group, while 5 patients treated with dabigatran had minor bleeding (34.8% vs. 13.2%, p = 0.02). Besides, 6 DRT (15.8%) were detected in dabigatran groups, and the incidence was higher than in the warfarin group (15.8% vs. 2.2%, p = 0.03). No DRT-related ischemic events were found.

CONCLUSIONS

This study suggested that short-term low-dose dabigatran (110 mg twice daily) could significantly decrease the risk of bleeding compared with warfarin at the expense of increased risk of DRT post-LAAO. Therefore, low-dose dabigatran should be used with caution for post-implant anticoagulation of LAAO. Further studies are urgently needed on the feasibility and safety of DOACs post-LAAO.

Comparison of Left Atrial Appendage Occlusion versus Non-Vitamin-K Antagonist Oral Anticoagulation in High-Risk Atrial Fibrillation: An Update

Transcatheter left atrial appendage occlusion (LAAO) is non-inferior to vitamin K antagonists (VKAs) in preventing thromboembolic events in atrial fibrillation (AF). Non-vitamin K antagonists (NOACs) have an improved safety profile over VKAs; however, evidence regarding their effect on cardiovascular and neurological outcomes relative to LAAO is limited. Up-to-date randomized trials or propensity-score-matched data comparing LAAO vs. NOACs in high-risk patients with AF were pooled in our study. A total of 2849 AF patients (LAAO: 1368, NOACs: 1481, mean age: 75 ± 7.5 yrs, 63.5% male) were enrolled. The mean CHA2DS2-VASc score was 4.3 ± 1.7, and the mean HAS-BLED score was 3.4 ± 1.2. The baseline characteristics were comparable between the two groups. In the LAAO group, the success rate of device implantation was 98.8%. During a mean follow-up of 2 years, as compared with NOACs, LAAO was associated with a significant reduction of ISTH major bleeding (p = 0.0002). There were no significant differences in terms of ischemic stroke (p = 0.61), ischemic stroke/thromboembolism (p = 0.63), ISTH major and clinically relevant minor bleeding (p = 0.73), cardiovascular death (p = 0.63), and all-cause mortality (p = 0.71). There was a trend toward reduction of combined major cardiovascular and neurological endpoints in the LAAO group (OR: 0.84, 95% CI: 0.64-1.11, p = 0.12). In conclusion, for high-risk AF patients, LAAO is associated with a significant reduction of ISTH major bleeding without increased ischemic events, as compared to "contemporary NOACs". The present data show the superior role of LAAO over NOACs among high-risk AF patients in terms of reduction of major bleeding; however, more randomized controlled trials are warranted.

Percutaneous Left Atrial Appendage Occlusion: An Emerging Option in Patients with Atrial Fibrillation at High Risk of Bleeding

Atrial fibrillation (AF) is a common cardiac arrhythmia with an estimated prevalence of 1% in the general population. It is associated with an increased risk of ischemic stroke, silent cerebral ischemia, and cognitive impairment. Due to the blood flow stasis and morphology, thrombus formation occurs mainly in the left atrial appendage (LAA), particularly in the setting of nonvalvular AF (NVAF). Previous studies have shown that >90% of emboli related to NVAF originate from the LAA, thus prevention of systemic cardioembolism is indicated. According to the current guidelines, anticoagulant therapy with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs), represents the standard of care in AF patients, in order to prevent ischemic stroke and peripheral embolization. Although these drugs are widely used and DOACs have shown, compared to VKAs, non-inferiority for stroke prevention with significantly fewer bleeding complications, some issues remain a matter of debate, including contraindications, side effects, and adherence. An increasing number of patients, indeed, because of high bleeding risk or after experiencing life-threatening bleedings, must take anticoagulants with extreme caution if not contraindicated. While surgical closure or exclusion of LAA has been historically used in patients with AF with contradictory results, in the recent years, a novel procedure has emerged to prevent the cardioembolic stroke in these patients: The percutaneous left atrial appendage occlusion (LAAO). Different devices have been developed in recent years, though not all of them are approved in Europe and some are still under clinical investigation. Currently available devices have shown a significant decrease in bleeding risk while maintaining efficacy in preventing thromboembolism. The procedure can be performed percutaneously through the femoral vein access, under general anesthesia. A transseptal puncture is required to access left atrium and is guided by transesophageal echocardiography (TEE). Evidence from the current literature indicates that percutaneous LAAO represents a safe alternative for those patients with contraindications for long-term oral anticoagulation. This review summarizes scientific evidences regarding LAAO for stroke prevention including clinical indications and an adequate patient selection.

Impact of Thrombocytopenia in Patients With Atrial Fibrillation Undergoing Left Atrial Appendage Occlusion: A Propensity-Matched Comparison of 190 Consecutive Watchman Implantations

Objectives: The purpose of this study was to provide data on the long-term efficacy and safety of left atrial appendage occlusion (LAAO) in patients with atrial fibrillation (AF) and chronic thrombocytopenia (cTCP).

Methods: Between January 2016 and December 2018, a total of 32 AF patients with thrombocytopenia (platelet count <100^*10^∧9/L) undergoing LAAO at our center were identified and their outcomes were compared with a propensity-matched cohort (match ratio 1:5) of patients without cTCP who had also been indicated for LAAO.

Results: Between the cTCP patients and the control group, no difference was found on the incidence of stroke (0 vs. 3.13%, p = 0.592), systematic thromboembolisation (0 vs. 0.63%, p > 0.9) and device-related thrombus (DRT) (3.13 vs. 2.50%, p > 0.9). Major (12.50 vs. 3.75%, p = 0.065) and minor bleeding (15.63 vs. 1.25%, p = 0.002) was more frequent in cTCP patients but no statistical difference was reached in major bleeding. Moreover, thrombocytopenia was also identified as an independent predictor of any bleeding events (OR: 8.150, 95% CI: 2.579–25.757, p < 0.001), while an inverse relationship between higher absolute platelet count and stroke events was revealed (OR: 1.015; 95% CI: 1.002~1.029, p = 0.022). However, in both groups we saw a significant reduction in observed annualized rates of non-procedural complications compared with the predicted values. In the cTCP and control groups, clinical thromboembolism was reduced by 100 and 74.32%, and major bleeding by 42.47 and 71.67%, respectively.

Conclusion: Our preliminary results indicate that LAAO using the Watchman device could be a safe and effective means of preventing stroke in AF patients with or without thrombocytopenia, but bleeding complications should be monitored intensively in cTCP patients.

Meta-analysis of postoperative antithrombotic therapy after left atrial appendage occlusion

Objective

This meta-analysis explored the safety and effectiveness of different anticoagulant regimens after left atrial appendage occlusion (LAAO).

Methods

Databases, such as PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Library, were searched to identify eligible studies according to the inclusion criteria. The incidences of events, including device-related thrombus (DRT) formation, stroke, systemic thromboembolism, bleeding, cardiovascular mortality, and all-cause mortality, were analyzed using R version 3.2.3.

Results

The screening retrieved 32 studies, including 36 study groups and 4,474 patients. The incidence of outcomes after LAAO was calculated via meta-analysis. In the subgroup analysis, the rates of DRT formation, cardiovascular mortality, and all-cause mortality were significantly different among different antithrombotic methods. Single antiplatelet therapy was associated with the highest rate of adverse events, followed by dual antiplatelet therapy (DAPT). Vitamin K antagonists (VKAs) and new oral anticoagulants (NOACs) carried lower rates of adverse events.

Conclusions

Anticoagulant therapy had better safety and efficacy than antiplatelet therapy. Thus, for patients with nonabsolute anticoagulant contraindications, anticoagulant therapy rather than DAPT should be actively selected. NOACs displayed potential for further development, and these treatments might represent alternatives to VKAs in the future.

Outcomes on safety and efficacy of left atrial appendage occlusion in end stage renal disease patients undergoing dialysis

BACKGROUND

In patients with end stage renal disease and atrial fibrillation (AF), undergoing chronic dialysis, direct oral agents are contraindicated and warfarin does not fully prevent embolic events while increasing the bleeding risk. The high hemorrhagic risk represents the main problem in this population. Aim of the study was to estimate the safety and efficacy for thromboembolic prevention of left atrial appendage (LAA) occlusion in a cohort of dialysis patients with AF and high hemorrhagic risk.

METHODS

Ninety-two dialysis patients with AF who underwent LAA occlusion were recruited. For comparative purposes, two cohorts of dialysis patients with AF, one taking warfarin (oral anticoagulant therapy, OAT cohort, n = 114) and the other not taking any OAT (no-therapy cohort, n = 148) were included in the study. Primary endpoints were (1) incidence of peri-procedural complications, (2) incidence of 2-year thromboembolic and hemorrhagic events, (3) mortality at 2 years. In order to evaluate the effect of the LAA occlusion on the endpoints with respect to the OAT and No-therapy cohorts, a multivariable Cox regression model was applied adjusted for possible confounding factors.

RESULTS

The device was successfully implanted in 100% of cases. Two major peri-procedural complications were reported. No thromboembolic events occurred at 2-year follow-up. The adjusted multivariable Cox regression model showed no difference in bleeding risk in the OAT compared to the LAA occlusion cohort in the first 3 months of follow-up [HR 1.65 (95% CI 0.43-6.33)], when most of patients were taking two antiplatelet drugs. In the following 21 months the bleeding incidence became higher in OAT patients [HR 6.48 (95% CI 1.32-31.72)]. Overall mortality was greater in both the OAT [HR 2.76 (95% CI 1.31-5.86)] and No-Therapy [HR 3.09 (95% CI 1.59-5.98)] cohorts compared to LAA occlusion patients.

CONCLUSIONS

The study could open the way to a non-pharmacological option for thromboembolic protection in dialysis patients with AF and high bleeding risk.

Watchman outcomes comparing post-implantation anticoagulation with warfarin versus direct oral anticoagulants

PURPOSE

As left atrial appendage occlusion devices (LAAO) implantation rates grow, continued evaluation on best patient practices is important. We report pooled Watchman outcomes at a multicenter Texas healthcare system with an emphasis on clinical outcomes and post-implantation anticoagulation with direct oral anticoagulants (DOACs) versus warfarin.

METHODS

Data for 163 patients with atrial fibrillation (AF) undergoing Watchman implantation was collected via retrospective chart review between June 2016 and June 2018. A Fisher's exact test was utilized to evaluate associations in bivariate comparisons of categorical data. Tests of non-inferiority, applied between DOACs and warfarin, utilized a ratio of 2.

RESULTS

Outcomes were significant for similar rates of stroke, disabling stroke, major bleeds, and all-cause mortality when compared to published clinical trials. Most patients with cerebrovascular events were found to have >5 mm peri-device leaks (PDLs), were on warfarin at the time of the event (75%), and all occurred within the first 6 months post implant. A significant number of patients were discharged on DOACs (42%). DOACs were shown to be non-inferior to warfarin with respect to stroke (p = 0.0048), disabling stroke (p = 0.0383), gastrointestinal bleeding (p = 0.0287), mortality (p = 0.0165), and combined adverse outcomes (p = 0.0040). DOACs were associated with less combined adverse outcomes (p = 0.021).

CONCLUSION

Our findings suggest that additional imaging or aggressive management of PDLs in Watchman recipients within the initial 6-month follow-up may aid in reducing stroke rates. Additionally, anticoagulation with DOACs' post Watchman implantation was found non-inferior to warfarin, with some evidence of lower risk for adverse outcomes favoring DOACs.

Short-Term Antiplatelet Versus Anticoagulant Therapy After Left Atrial Appendage Occlusion: A Systematic Review and Meta-Analysis

OBJECTIVES

The aim of this study was to compare bleeding, thromboembolic, device-related thrombus (DRT), and all-cause mortality events between patients treated with short-term oral anticoagulation (OAC) and those treated with short-term antiplatelet therapy (APT) following left atrial appendage occlusion (LAAO).

BACKGROUND

Short-term OAC is recommended for patients following LAAO. However, in practice many patients receive APT rather than OAC because of excessive bleeding risk. However, the safety and efficacy of APT compared with OAC have been debated.

METHODS

A search was conducted of databases for studies comparing OAC with APT following LAAO. The outcomes of interest were all-cause stroke, major bleeding, DRT, and all-cause mortality. Noncomparative studies were pooled into a single study to generate comparisons of the studies' outcomes. Effects measure were pooled using the random-effect model.

RESULTS

A total of 83 studies with 12,326 patients (APT, n = 7,900; OAC, n = 4,151) were included. Mean CHA2DS2-VASc and HAS-BLED scores were 4.1 ± 1.6 and 3.0 ± 1.3, respectively. There were no significance differences between the APT and OAC groups with regard to stroke (risk ratio [RR]: 1.04; 95% confidence interval [CI]: 0.54 to 1.98; p = 0.91; I2 = 31%), major bleeding (RR: 1.12; 95% CI: 0.68 to 1.84; p = 0.65; I2 = 53%), DRT (RR: 1.33; 95% CI: 0.74 to 2.39; p = 0.33; I2 = 36%), and all-cause mortality (RR: 1.29; 95% CI: 0.40 to 4.09; p = 0.18; I2 = 36%). These findings persisted in multiple secondary analyses: 1) excluding studies that reported no events; 2) including comparative studies only; 3) excluding patients who were treated with single APT; and 4) removing one study at a time to assess the effect of each study on the overall effect size. There was also no difference in the studies' endpoints among patients who received different LAAO devices.

CONCLUSIONS

In a meta-analysis of observational data, there were no differences in the occurrence of stroke, major bleeding DRT, and all-cause mortality in patients treated with short-term OAC or APT following LAAO.

Acute Device-Related Thrombus after Watchman Device Implant

Atrial fibrillation is characterized by irregularly irregular heart rhythm with an increased morbidity and mortality. It is associated with an increased risk of thromboembolism due to formation of blood clot in the left atrium. Most of these blood clots are formed in the left atrial appendage. The risk of blood clot formation is reduced with the use of anticoagulants. The patients who cannot take anticoagulants due to an increased bleeding risk can undergo percutaneous left atrial appendage (LAA) closure. A Watchman device is used for this purpose. LAA closure with the Watchman device is associated with some adverse effects, and one of them is device-related thrombus. Currently, there are no specific guidelines for the management of device-related thrombus. We present a case of Watchman device-related thrombus which developed 16 hours after the device placement. We will also discuss various options for the management of acute thrombosis.