Aspirin versus vitamin K antagonist treatment guided by transoesophageal echocardiography in patients with atrial fibrillation: a pilot study

Atherothrombosis and Thromboembolism: Position Paper from the Second Maastricht Consensus Conference on Thrombosis

Atherothrombosis is a leading cause of cardiovascular mortality and long-term morbidity. Platelets and coagulation proteases, interacting with circulating cells and in different vascular beds, modify several complex pathologies including atherosclerosis. In the second Maastricht Consensus Conference on Thrombosis, this theme was addressed by diverse scientists from bench to bedside. All presentations were discussed with audience members and the results of these discussions were incorporated in the final document that presents a state-of-the-art reflection of expert opinions and consensus recommendations regarding the following five topics: 1. Risk factors, biomarkers and plaque instability: In atherothrombosis research, more focus on the contribution of specific risk factors like ectopic fat needs to be considered; definitions of atherothrombosis are important distinguishing different phases of disease, including plaque (in)stability; proteomic and metabolomics data are to be added to genetic information. 2. Circulating cells including platelets and atherothrombosis: Mechanisms of leukocyte and macrophage plasticity, migration, and transformation in murine atherosclerosis need to be considered; disease mechanism-based biomarkers need to be identified; experimental systems are needed that incorporate whole-blood flow to understand how red blood cells influence thrombus formation and stability; knowledge on platelet heterogeneity and priming conditions needs to be translated toward the in vivo situation. 3. Coagulation proteases, fibrin(ogen) and thrombus formation: The role of factor (F) XI in thrombosis including the lower margins of this factor related to safe and effective antithrombotic therapy needs to be established; FXI is a key regulator in linking platelets, thrombin generation, and inflammatory mechanisms in a renin-angiotensin dependent manner; however, the impact on thrombin-dependent PAR signaling needs further study; the fundamental mechanisms in FXIII biology and biochemistry and its impact on thrombus biophysical characteristics need to be explored; the interactions of red cells and fibrin formation and its consequences for thrombus formation and lysis need to be addressed. Platelet-fibrin interactions are pivotal determinants of clot formation and stability with potential therapeutic consequences. 4. Preventive and acute treatment of atherothrombosis and arterial embolism; novel ways and tailoring? The role of protease-activated receptor (PAR)-4 vis à vis PAR-1 as target for antithrombotic therapy merits study; ongoing trials on platelet function test-based antiplatelet therapy adjustment support development of practically feasible tests; risk scores for patients with atrial fibrillation need refinement, taking new biomarkers including coagulation into account; risk scores that consider organ system differences in bleeding may have added value; all forms of oral anticoagulant treatment require better organization, including education and emergency access; laboratory testing still needs rapidly available sensitive tests with short turnaround time. 5. Pleiotropy of coagulation proteases, thrombus resolution and ischaemia-reperfusion: Biobanks specifically for thrombus storage and analysis are needed; further studies on novel modified activated protein C-based agents are required including its cytoprotective properties; new avenues for optimizing treatment of patients with ischaemic stroke are needed, also including novel agents that modify fibrinolytic activity (aimed at plasminogen activator inhibitor-1 and thrombin activatable fibrinolysis inhibitor.

The Efficacy and Safety of 3 Types of Interventions for Stroke Prevention in Patients With Cardiovascular and Cerebrovascular Diseases: A Network Meta-analysis

PURPOSE

The goal of this study was to compare the relative efficacy and safety of different types of interventions for stroke prevention in patients with cardiovascular and cerebrovascular diseases.

METHODS

This network meta-analysis (NMA) was conducted with a random effects model of Bayesian framework using Stata version 12.0. Odds ratios (ORs) and their credible intervals (CrIs) were applied for the efficacy and safety evaluation of various medical interventions, including aspirin, dipyridamole, ticlopidine, warfarin, and apixaban. In addition, the ranking of probability of every clinical outcome was estimated by comparing the surface under the cumulative ranking curve.

FINDINGS

Compared with dabigatran, both edoxaban and aspirin + warfarin exhibited a higher rate of all-cause stroke (OR, 2.84 [95% CrI, 1.17-6.97]; OR, 3.42 [95% CrI, 1.20-9.84]). With respect to intracranial hemorrhage, aspirin + clopidogrel yielded worse outcomes than 7 treatments, including placebo, apixaban, aspirin, aspirin + dipyridamole, cilostazol, clopidogrel, and dabigatran (OR, 2.21 [95% CrI, 1.45-3.40]; OR, 2.11 [95% CrI, 1.05-4.17]; OR, 1.53 [95% CrI, 1.11-2.15]; OR, 1.78 [95% CrI, 1.01-3.03]; OR, 4.17 [95% CrI, 1.37-14.28]; OR, 1.85 [95% CrI, 1.22-2.86]; and OR, 2.56 [95% CrI, 1.37-4.76]). In terms of ischemic stroke, dabigatran provided better efficacy than placebo, aspirin, and aspirin + dipyridamole (OR, 0.36 [95% CrI, 0.18-0.72]; OR, 0.43 [95% CrI, 0.21-0.84]; and OR, 0.41 [95% CrI, 0.17-0.94]). As for mortality, dabigatran resulted in a lower mortality compared with aspirin, aspirin + clopidogrel, edoxaban, and warfarin (OR, 0.48 [95% CrI, 0.23-0.97]; OR, 0.40 [95% CrI, 0.17-0.92]; OR, 0.27 [95% CrI, 0.10-0.72]; and OR, 0.52 [95% CrI, 0.28-0.92]).

IMPLICATIONS

There are still some limitations to our NMA research. For instance, the lack of direct evidence for some therapies resulted in inconsistencies, particularly for warfarin compared with placebo and clopidogrel under different end points. Moreover, the included randomized controlled trials for patients with cardiovascular and cerebrovascular diseases are relatively broad, involving atrial fibrillation, myocardial infarction, and large-artery atherosclerosis stroke. Although further research is needed, dabigatran is highly recommended based on the present NAM for the treatment of cardiovascular and cerebrovascular diseases due to the drug's efficacy and safety.

Clinical characteristics of complex aortic plaque in patients with non-valvular atrial fibrillation

BACKGROUND

Although complex aortic plaque (CxAoP) is a component of the CHA₂DS₂-VASc score in patients with atrial fibrillation (AF), it is underestimated without detection by trans-esophageal echocardiogram (TEE). We have evaluated the incidence and significance of CxAoP among patients with non-valvular AF (NVAF).

METHODS

We included 981 patients with NVAF who underwent catheter ablation (59.1±11.1years old, 73.7% male, 70.2% paroxysmal AF). All of the patients underwent pre-procedural TEE evaluation. Left atrial (LA)-cardioembolic (CE) milieu was defined as a dense spontaneous echo-contrast or LA appendage flow velocity≤20cm/s.

RESULTS

CxAoP was present in 8.3% of patients, and independently associated with age (OR 1.07, 95% CI 1.03-1.10, p<0.001), male sex (OR 2.34, 95% CI 1.29-4.24, p=0.005), and CHA₂DS₂-VASc score≥2 (OR 3.33, 95%CI 1.42-7.77, p=0.005). The presence of LA-CE milieu overlapped with CxAoP in only 11% of patients. Patients with CxAoP had a higher prevalence of hypertension (p=0.004), smoking history (p=0.008), paroxysmal AF (PAF, p<0.001), and a smaller LA volume index (p<0.001) than those with LA-CE milieu. The prevalence of persistent AF among patients with a history of stroke was significantly lower in the presence of CxAoP than in those with LA-CE milieu (p=0.014). CHA₂DS₂-VASc score was underestimated in 11% of high-risk patients (CHA₂DS₂-VASc score≥2) due to undetected CxAoP.

CONCLUSIONS

CxAoP may contribute to the risk of stroke by a different mechanism than LA-CE milieu in patients with NVAF. Imaging assessment for CxAoP affects thromboembolic risk stratification and decision making for stroke prevention in patients with NVAF.

Is CHA2DS2-VASc appropriate for hyperthyroid patients with atrial fibrillation? Implications of adding a transesophageal echocardiography evaluation

BACKGROUND

Anticoagulation remains a controversial issue among hyperthyroid patients with atrial fibrillation (AF). We aimed to evaluate the prevalence of the thrombogenic milieu (TM), detected using transesophageal echocardiography (TEE), among patients with AF related to hyperthyroidism, and to correlate these findings with the clinical embolic risk classification (CHA₂DS₂-VASc).

METHODS

CHA₂DS₂-VASc score, thyroid hormonal status, time since hyperthyroidism diagnosis, transthoracic echocardiography (TTE) and TEE were assessed in 47 consecutive patients aged between 18 and 65years with AF related to hyperthyroidism. The following TEE parameters defined TM: dense spontaneous echo contrast, thrombi, or left atrial appendage (LAA) blood flow velocities <0.20m/s. Non-classic TM was defined as non-dense SEC plus LAA flow velocity 0.20-0.40m/s.

RESULTS

Pulmonary hypertension was present in 39/47 (81.4%) and TM in 22/47 (46.8%) patients. Despite a low CHA₂DS₂-VASc score of 0/1, 10 of 19 (52.6%) patients had a TM, whereas 16 of 28 (57.1%) patients with score ≥2 had none. The probability of having a TM did not correlate with CHA₂DS₂-VASc scores. On regression binary analysis, hyperthyroidism diagnosed more than 12months previous was independently associated with non-classic TM (p=0.031).

CONCLUSION

Among patients younger than 65years of age with AF related to hyperthyroidism, pulmonary hypertension and TM on TEE were highly prevalent. There was no association between CHA₂DS₂-VASc with TEE markers of TM. Thyroid status, especially longer duration of hyperthyroidism might influence thrombogenic abnormalities. TEE adds useful information that may change antithrombotic therapy if otherwise guided solely by clinical risk classification.

Almanac 2015: atrial fibrillation research in Heart

Atrial fibrillation continues to attract interest in the cardiovascular community and in Heart. Over 60 original research and review papers published in Heart in 2014–2015 cover various aspects of atrial fibrillation, from associated conditions and precipitating factors to new approaches to management. Here, we provide an overview of articles on atrial fibrillation published in Heart in 2014–2015, highlighting new developments, emerging concepts and novel approaches to treatment.

Left atrial volume and function in patients with atrial fibrillation

PURPOSE OF REVIEW

This review of emerging approaches to left atrial imaging in atrial fibrillation is relevant because there has been considerable recent development in the noninvasive characterization of left atrial structure and function. Concurrently, the identification and treatment of atrial fibrillation and the prevention of thromboembolism are evolving. Thus, it is timely to summarize how the advances in these two areas might be synergistic in the treatment of atrial fibrillation.

RECENT FINDINGS

This article will summarize recent developments in left atrial imaging that play a role in patients with atrial fibrillation, with particular emphasis on echocardiography, and with reference made to important advances in cardiac computed tomography and cardiac magnetic resonance. The evidence that these modalities can predict who will develop atrial fibrillation, who will achieve sustained sinus rhythm after cardioversion or catheter ablation, and who will have thromboembolic risk will be reviewed.

SUMMARY

Although existing evidence is promising, the clinical role of cardiac imaging to predict atrial fibrillation occurrence, atrial fibrillation recurrence after treatment, and thromboembolism from atrial fibrillation remains to be confirmed in large-scale studies and clinical trials.