Risk Of Thromboembolic Stroke Research Articles

Predictors of left atrial appendage emptying velocity: Derivation and validation of CHIRP3(M-1) score

Atrial fibrillation (AF) leads to impaired left atrial appendage contractility, increasing the risk of thromboembolic stroke. The left atrial appendage emptying velocity (LAAev) measured on transesophageal echocardiogram (TEE) is a marker of increased thromboembolic risk. To evaluate predictors of reduced LAAev for identifying individuals at increased risk of cardiogenic stroke. This was a single-center retrospective review of TEEs and clinical charts. Predictors of LAAev <30 cm/s were identified using logistic regression. A risk prediction model was created using stepwise selection in a derivation set (n=695) and separately tested in a validated set (n=300). We included TEEs on 995 patients (age 71.3±12.7 years, female 38.1%, history of AF 82.1%, in AF at evaluation 27.7%, CHA2DS2-VASc score 4.1±1.9, LAAev 41.6±21.0 cm/s). Significant multivariable predictors of LAAev <30 cm/s in derivation set were used to create the CHIRP3M-1 score containing 8 variables: Coronary artery disease (1), congestive Heart failure (1), Increased left atrial volume index ≥42 mL/m2 (1), current Rhythm AF (1), Paroxysmal AF (2), Persistent AF (3), long standing Persistent/permanent AF (4), and >moderate Mitral regurgitation (-1). In the validation set, as compared to intermediate scores (3-4), those with a low scores (≤2) and high scores (≥5) had odds ratios for LAAev <30 cm/s of 0.41 (0.21, 0.78, p=0.007) and 2.58 (95% CI 1.45, 4.61, p=0.001) respectively. We developed and validated a novel risk stratification system to predict reduced LAAev using clinical and echocardiographic variables. This may help refine the stratification of cardiogenic stroke risk.

Current Gaps in the Provision of Safe and Effective Anticoagulation in Atrial Fibrillation and the Potential for Factor XI-Directed Therapeutics.

The global prevalence of atrial fibrillation is rapidly increasing, in large part due to the aging of the population. Atrial fibrillation is known to increase the risk of thromboembolic stroke by 5 times, but it has been evident for decades that well-managed anticoagulation therapy can greatly attenuate this risk. Despite advances in pharmacology (such as the shift from vitamin K antagonists to direct oral anticoagulants) that have increased the safety and convenience of chronic oral anticoagulation in atrial fibrillation, a preponderance of recent observational data indicates that protection from stroke is poorly achieved on a population basis. This outcomes deficit is multifactorial in origin, stemming from a combination of underprescribing of anticoagulants (often as a result of bleeding concerns by prescribers), limitations of the drugs themselves (drug-drug interactions, bioaccumulation in renal insufficiency, short half-lives that result in lapses in therapeutic effect, etc), and suboptimal patient adherence that results from lack of understanding/education, polypharmacy, fear of bleeding, forgetfulness, and socioeconomic barriers, among other obstacles. Often this adherence is not reported to treating clinicians, further subverting efforts to optimize care. A multidisciplinary, interprofessional panel of clinicians met during the 2023 International Society of Thrombosis and Haemostasis Congress to discuss these gaps in therapy, how they can be more readily recognized, and the potential for factor XI-directed anticoagulants to improve the safety and efficacy of stroke prevention. A full appreciation of this potential requires a reevaluation of traditional teaching about the "coagulation cascade" and decoupling the processes that result in (physiologic) hemostasis and (pathologic) thrombosis. The panel discussion is summarized and presented here.

Real-Time Detection of Circulating Thrombi in an Extracorporeal Circuit Using Doppler Ultrasound: In-Vitro Proof of Concept Study.

Thromboembolic stroke continues to be by far the most common severe adverse event in patients supported with mechanical circulatory assist devices. Feasibility of using Doppler ultrasound to detect circulating thrombi in an extracorporeal circuit was investigated. A mock extracorporeal circulatory loop of uncoated cardiopulmonary bypass tubing and a roller pump was setup. A Doppler bubble counter was used to monitor the mean ultrasound backscatter signal (MUBS). The study involved two sets of experiments. In Scenario 1, the circuit was sequentially primed with human blood components, and the MUBS was measured. In Scenario 2, the circuit was primed with heparinized fresh porcine blood, and the MUBS was measured. Fresh blood clots (diameter <1,000 microns, 1,000-5,000 microns, >5,000 microns) were injected into the circuit followed by protamine administration. In Scenario 1 (n = 3), human platelets produced a baseline MUBS of 1.5 to 3.5 volts/s. Addition of packed human red blood cells increased the baseline backscatter to 17 to 21 volts/s. Addition of fresh frozen plasma did not change the baseline backscatter. In Scenario 2 (n = 5), the blood-primed circuit produced a steady baseline MUBS. Injection of the clots resulted in abrupt and transient increase (range: 3-30 volts/s) of the baseline MUBS. Protamine administration resulted in a sustained increase of MUBS followed by circuit thrombosis. Doppler ultrasound may be used for real-time detection of circulating solid microemboli in the extracorporeal circuit. This technology could potentially be used to design safety systems that can reduce the risk of thromboembolic stroke associated with mechanical circulatory support therapy.

Anticoagulant Prescribing Patterns in New-Onset Atrial Fibrillation After Cardiac Surgery

BackgroundPostoperative atrial fibrillation (POAF) is a common complication after cardiac surgery and is associated with an increased risk of thromboembolic stroke. Recommendations regarding the optimal anticoagulant, timing of initiation, and duration of therapy remain uncertain. MethodsAdministrative databases were used to include adult patients who presented with POAF after cardiac surgery between January 1, 2015, and December 31, 2020. Key exclusion criteria included preexisting atrial fibrillation, mechanical valve replacement, or anticoagulant prescription fill within 6 months before the index admission. ResultsA total of 3214 of patients were included, and 878 (27.3%) were prescribed an oral anticoagulant (OAC) on discharge, with 536 (61%) prescribed warfarin and 342 (39%) prescribed a direct OAC. More than half of the patients (56.1%) stopped their OAC by 6 months. There was no difference in stroke or systemic embolism at 30 days, 3 months, or 6 months between those with and without anticoagulation prescribed. However, those on any OAC had higher rates of any bleeding at all time points. ConclusionsA minority of patients who presented with POAF after cardiac surgery were prescribed OAC, with warfarin being the most common agent. OAC initiation was associated with increased bleeding risk, warranting special consideration when assessing a patient’s risk of stroke with the increased risk of bleeding, particularly in the postoperative period.

Myosin light chain dephosphorylation by ppp1r12c promotes atrial hypocontractility in atrial fibrillation

Abstract Background Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, increases thromboembolic stroke risk five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C, the PP1 regulatory subunit targeting atrial myosin light chain 2 (MLC2a), causes hypophosphorylation of MLC2a and results in atrial hypocontractility. Methods Right atrial appendage tissues were isolated from human AF patients versus sinus rhythm (SR) controls. Western blots, co-immunoprecipitation, and phosphorylation studies were performed to examine how the PP1c-PPP1R12C interaction causes MLC2a de-phosphorylation. In vitro studies of pharmacologic MRCK inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with EP studies. Results In human patients with AF, PPP1R12C expression was increased two-fold versus SR controls (P=0.02, n=12,12 in each group) with &amp;gt; 40% reduction in MLC2a phosphorylation (P=0.000001, n=12,12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF (P=0.03 and 0.007 respectively, n=8,8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Lenti-12C mice demonstrated a 150% increase in LA size versus controls (P=5.0x10-6, n=12,8,12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in Lenti-12C mice was significantly higher than controls (P=0.02 and 0.04 respectively, n= 6,6,5). Conclusions AF patients exhibit increased levels of PPP1R12C protein compared to controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key regulator of atrial contractility in AF.

PPP1R12C Promotes Atrial Hypocontractility in Atrial Fibrillation.

Atrial fibrillation (AF)-the most common sustained cardiac arrhythmia-increases thromboembolic stroke risk 5-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C (protein phosphatase 1 regulatory subunit 12C)-the PP1 (protein phosphatase 1) regulatory subunit targeting MLC2a (atrial myosin light chain 2)-causes hypophosphorylation of MLC2a and results in atrial hypocontractility. Right atrial appendage tissues were isolated from human patients with AF versus sinus rhythm controls. Western blots, coimmunoprecipitation, and phosphorylation studies were performed to examine how the PP1c (PP1 catalytic subunit)-PPP1R12C interaction causes MLC2a dephosphorylation. In vitro studies of pharmacological MRCK (myotonic dystrophy kinase-related Cdc42-binding kinase) inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with electrophysiology studies. In human patients with AF, PPP1R12C expression was increased 2-fold versus sinus rhythm controls (P=2.0×10-2; n=12 and 12 in each group) with >40% reduction in MLC2a phosphorylation (P=1.4×10-6; n=12 and 12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF (P=2.9×10-2 and 6.7×10-3, respectively; n=8 and 8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a and dephosphorylation of MLC2a. Mice treated with lentiviral PPP1R12C vector demonstrated a 150% increase in left atrial size versus controls (P=5.0×10-6; n=12, 8, and 12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in mice treated with lentiviral PPP1R12C vector was significantly higher than in controls (P=1.8×10-2 and 4.1×10-2, respectively; n=6, 6, and 5). Patients with AF exhibit increased levels of PPP1R12C protein compared with controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key determinant of atrial contractility in AF.

Meta-Analysis of the Outcomes of Peri-Device Leak After Left Atrial Appendage Closure

Left atrial appendage closure (LAAC) reduces the risk of thromboembolic stroke in atrial fibrillation. Peri-device leak (PDL) after LAAC may affect the subsequent risk of thromboembolism. We conducted a systematic review and meta-analysis to evaluate the effect of PDL after LAAC. We searched PubMed/Medline, Embase, and Google Scholar for studies reporting outcomes of PDL after LAAC from inception through October 2022. The primary outcome was the composite of stroke, transient ischemic attack (TIA), or systemic embolism (SE). Secondary outcomes included all-cause and cardiovascular mortality, ischemic stroke, TIA, and device-related thrombus. Outcomes were pooled using random-effects models. We used I2 statistics to assess statistical heterogeneity; I2 >50% considered significant heterogeneity. This study included 54,279 patients from 11 studies (6 observational, 2 nonrandomized controlled trials [non-RCTs] primary results, 2 RCT post hoc analyses, and 1 analysis combining 2 RCTs data). PDL was associated with a significant increase in the composite outcome of stroke, TIA, or SE (odds ratio 1.63, 95% confidence interval 1.06 to 2.52, p=0.03, I2=43%) as compared with cases with no PDL. There were no significant differences in all-cause or cardiovascular mortality, ischemic stroke, TIA, or device-related thrombus. In conclusion, PDL after LAAC is associated with an increased risk of thromboembolism (composite stroke, TIA, or SE) without impacting mortality.

Abstract EC.02: Myosin Light Chain Dephosphorylation By Ppp1r12c Promotes Atria Hypocontractility In Atrial Fibrillation

Background: Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, increases thromboembolic stroke risk five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C, the PP1 regulatory subunit targeting atrial myosin light chain 2 (MLC2a), causes hypophosphorylation of MLC2a and results in atrial hypocontractility. Methods: Right atrial appendage tissues were isolated from human AF patients versus sinus rhythm (SR) controls. Western blots, co-immunoprecipitation, and phosphorylation studies were performed to examine how the PP1c-PPP1R12C interaction causes MLC2a de-phosphorylation. In vitro studies of pharmacologic MRCK inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with EP studies. Results: In human patients with AF, PPP1R12C expression was increased two-fold versus SR controls with &gt; 40% reduction in MLC2a phosphorylation. 12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF. In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Lenti-12C mice demonstrated a 150% increase in LA size versus controls, with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in Lenti-12C mice was significantly higher than controls. Conclusions: AF patients exhibit increased levels of PPP1R12C protein compared to controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key regulator of atrial contractility in AF.

Copy number variation of gasdermin D gene is associated with atrial fibrillation-related thromboembolic stroke.

Atrial fibrillation (AF) is one of the major causes of ischaemic stroke. In addition to clinical risk evaluated by the CHA2DS2-VASC score, the impact of genetic factors on the risk of AF-related thromboembolic stroke has been largely unknown. We found several copy number variations (CNVs) in novel genes that were associated with thromboembolic stroke risk in our AF patients by genome-wide approach. Among them, the gasdermin D (GSDMD) gene was related to inflammation. We aimed to test whether GSDMD deletion was associated with AF-related stroke. A total of 400 patients with documented non-familial AF were selected, of which 100 patients were diagnosed with ischaemic stroke. The baseline characteristics of age, sex, valvular heart disease, coronary artery disease, heart failure, and CHA2DS2-VASc scores were not statistically different between cases and controls. We found that individuals who carried GSDMD homozygous deletion genotype had a higher risk for ischaemic stroke (odds ratio 2.195; 95% confidence interval, 1.24-3.90; P = 0.007), even adjusted by CHA2DS2-VASc scores. We also validated the association of GSDMD with AF stroke in a large Caucasian population (UK Biobank). We found a link between the homozygous deletion of the GSDMD gene and an increased risk of stroke in patients with AF. This may implicate the use of therapy targeting GSDMD in the prevention of ischaemic stroke for AF patients.

Cardiovascular Complications of Interatrial Conduction Block: JACC State-of-the-Art Review.

Interatrial block (IAB) is an electrocardiographic pattern describing the conduction delay between the right and left atria. IAB is classified into 3 degrees of block that correspond to decreasing conduction in the region of Bachmann's bundle. Although initially considered benign in nature, specific subsets of IAB have been associated with atrial arrhythmias, elevated thromboembolic stroke risk, cognitive impairment, and mortality. As the pathophysiologic relationships between IAB and stroke are reinforced, investigation has now turned to the potential benefit of early detection, atrialimaging, cardiovascular risk factor modification, antiarrhythmic pharmacotherapy, and stroke prevention with oralanticoagulation. This review provides a contemporary overview of the epidemiology, pathophysiology, diagnosis, and management of IAB, with a focus on future directions.

Explainable Machine Learning for Atrial Fibrillation in the General Population Using a Generalized Additive Model - A Cross-Sectional Study.

Background: Atrial fibrillation (AF) is the most common arrhythmia and is associated with increased thromboembolic stroke risk and heart failure. Although various prediction models for AF risk have been developed using machine learning, their output cannot be accurately explained to doctors and patients. Therefore, we developed an explainable model with high interpretability and accuracy accounting for the non-linear effects of clinical characteristics on AF incidence. Methods and Results: Of the 489,073 residents who underwent specific health checkups between 2009 and 2018 and were registered in the Kanazawa Medical Association database, data were used for 5,378 subjects with AF and 167,950 subjects with normal electrocardiogram readings. Forty-seven clinical parameters were combined using a generalized additive model algorithm. We validated the model and found that the area under the curve, sensitivity, and specificity were 0.964, 0.879, and 0.920, respectively. The 9 most important variables were the physical examination of arrhythmia, a medical history of coronary artery disease, age, hematocrit, γ-glutamyl transpeptidase, creatinine, hemoglobin, systolic blood pressure, and HbA1c. Further, non-linear relationships of clinical variables to the probability of AF diagnosis were visualized. Conclusions: We established a novel AF risk explanation model with high interpretability and accuracy accounting for non-linear information obtained at general health checkups. This model contributes not only to more accurate AF risk prediction, but also to a greater understanding of the effects of each characteristic.

Left Atrial Appendage Closure: An Alternative to Anticoagulation for Stroke Prevention in Patients with Kidney Disease.

Anticoagulation to reduce thromboembolic stroke risk due to nonvalvular atrial fibrillation in ESKD is associated with increased bleeding. There is an existing debate in ESKD centers around the pros and cons of anticoagulation. We propose percutaneous left atrial appendage occlusion as a third alternative to balance thrombosis and bleeding risks in this high-risk population.

A novel PRRX1 loss-of-function variation contributing to familial atrial fibrillation and congenital patent ductus arteriosus.

Atrial fibrillation (AF) represents the most common type of sustained cardiac arrhythmia in humans and confers a significantly increased risk for thromboembolic stroke, congestive heart failure and premature death. Aggregating evidence emphasizes the predominant genetic defects underpinning AF and an increasing number of deleterious variations in more than 50 genes have been involved in the pathogenesis of AF. Nevertheless, the genetic basis underlying AF remains incompletely understood. In the current research, by whole-exome sequencing and Sanger sequencing analysis in a family with autosomal-dominant AF and congenital patent ductus arteriosus (PDA), a novel heterozygous variation in the PRRX1 gene encoding a homeobox transcription factor critical for cardiovascular development, NM_022716.4:c.373G>T;p.(Glu125*), was identified to be in co-segregation with AF and PDA in the whole family. The truncating variation was not detected in 306 unrelated healthy individuals employed as controls. Quantitative biological measurements with a reporter gene analysis system revealed that the Glu125*-mutant PRRX1 protein failed to transactivate its downstream target genes SHOX2 and ISL1, two genes that have been causally linked to AF. Conclusively, the present study firstly links PRRX1 loss-of-function variation to AF and PDA, suggesting that AF and PDA share a common abnormal developmental basis in a proportion of cases.

Real world radiation exposure in left atrial appendage occlusion device implantation performed in a high volume center

Abstract Left atrial appendage occlusion (LAAO) is an established and effective treatment to reduce the risk of thromboembolic stroke derived from the LAA in patient with non valvular atrial fibrillation. Per-cutaneous closure of the LAA is typically guided by fluoroscopic and echocardiographic guidance. The purpose of our study is to ascertain real world radiation exposure during the LAAO performed in our institution and the interplay of different variables and patient characteristics. Our study retrospectively analyzed all consecutive LAAO procedures performed at our Tertiary level Teaching Hospital. Data was collected using Hospital electronic records and cardiac catherization laboratory records. A total of 261 patients who underwent LAAO were identified, 28% were female. Average age at the time of procedure was 77 years (range 54–93 years). Mean fluoroscopy time was 10.2 minutes (±7.0), average Radiation dose was 67 gy/cm2 (±73). Interestingly, gy/cm2 per minute of fluoroscopy averaged at 6.69 (±5.0). Subgroup analysis focused on the effect of Body mass index (BMI) on radiation dose. Since the recent introduction of a partial electronic health record system, BMI data was only available on 161 patients. The cohort with BMI &amp;lt;30 had a mean radiation dose of 57±62 gy/cm2, whereas for BMI &amp;gt;30 mean dose was 96.8±68, p=0.0025 (95% CI (65 to 14)). Analysis by the four different device types (Watchman, Watchman Flx, Wavecrest and ACP) were used for LAAO, with highest number been watchman (n=189). Upon comparing the radiation exposure in our study cohort watchman device had the least Dose adjusted Product (DAP) at 62gy/cm2 but the newer watchman flx (n=25) had slightly lower gy/cm2 per minute of fluoroscopy time 6.58±3.41 versus 6.83±5.56. In addition, operator volume between our two implanters was assessed. Our highest volume operator implanted the majority of devices (n=235) whilst the Watchman Flx was predominantly implanted by our newer implanter (n=26). Despite the relatively modest numbers of the Watchman Flx, there was minimal difference in exposure time in favor of the more senior interventionist. In conclusion, LAAO in our center has encouraging radiation safety data, which is comparable to previously published data in internationally recognized high volume centers. Normal BMI patients had the least radiation exposure, with the dose increasing with rising BMI. Funding Acknowledgement Type of funding sources: None. Bar Graph, radiation dose vs BMIScatter Plot, radiation dose vs BMI

Left atrial enlargement and long-term risk of thromboembolic stroke after ST-segment elevation myocardial infarction

Left atrial enlargement and long-term risk of thromboembolic stroke after ST-segment elevation myocardial infarction

Robotics-assisted epicardial left atrial appendage clip exclusion.

ObjectivesWe demonstrate the feasibility and safety of robotics-assisted left atrial appendage clip exclusion in clinical practice.MethodsAnalysis of a single center robotics-assisted left atrial appendage clip exclusion experience using an epicardial linear clip device in patients with atrial fibrillation with high-risk of thromboembolic stroke and intolerance to oral anticoagulants.ResultsDuring the period from December 2017 to September 2020, we performed 42 robotics-assisted left atrial appendage clip exclusions in response to increased risk of bleeding in patients with atrial fibrillation and intolerance to oral anticoagulants. The average congestive heart failure, hypertension, age, diabetes, stroke, and vascular disease score was 5.2 ± 1.6 and hypertension, abnormal liver or kidney function, stroke, bleeding, labile international normalized ratio, elderly, drugs (aspirin, other antiplatelets, or anticoagulants) score was 4.5 ± 0.9. No patients died intraoperatively or within 30 days, or due to conversion to thoracotomy, intraoperative complications, or failure to apply the clip satisfactorily. The procedure was successfully completed despite pericardial adhesions in 2 patients with prior coronary bypass grafts and 3 with postpericarditis scars. Intraoperative transesophageal echocardiography was performed in 38 out of 42 patients; satisfactory exclusion with left atrial appendage stump <5 mm was confirmed in all. Average length of stay was 3.4 ± 3 days with 12 out of 42 patients discharged within 24 hours. Oral anticoagulants were discontinued in 41 out of 42 patients and no cases of 30-day stroke, myocardial ischemia, or new arrhythmias were observed. One case of hemothorax required thoracoscopy a day later. There was no reported thromboembolic stroke or transient ischemic attack at 12 months. One case of late lacunar stroke was due to in situ small intracranial vessel thrombosis without left atrial appendage thrombus on imaging.ConclusionsRobotics-assisted left atrial appendage clip exclusion is a safe and feasible minimally invasive method for left atrial appendage management in patients with atrial fibrillation with intolerance to oral anticoagulants and increased risk of thromboembolic stroke.

Early Thromboembolic Stroke Risk of Postoperative Atrial Fibrillation Following Cardiac Surgery

The authors aimed to study the association between postoperative atrial fibrillation (POAF) and thromboembolic stroke and to determine risk factors for thromboembolic stroke after cardiac surgery. The authors performed a secondary analysis from a randomized controlled trial (GRIP-COMPASS). The patients with thromboembolic stroke were compared with those without thromboembolic stroke, and the difference in the incidence of POAF between these groups was assessed. Odds ratios (OR) were calculated using logistic regression analyses. Brain imaging was studied for the occurrence of thromboembolic stroke during hospital admission, and POAF was monitored for seven days. To assess which characteristics were associated with occurrence of thromboembolic stroke, stepwise backward regression analysis was performed. All adult consecutive cardiac surgery patients admitted postoperatively to the intensive care unit. Academic tertiary care medical center. None. Of the 910 patients included in this study, 26 patients (2.9%) had a thromboembolic stroke during hospital admission. The incidence of POAF during the first seven days after cardiac surgery in those with thromboembolic stroke was 65%, compared with 39% in those without thromboembolic stroke: adjusted OR 3.01 (95% confidence interval, 1.13-8.00). POAF, a history of peripheral vascular disease, a higher EuroSCORE, and a longer duration of surgery were associated with thromboembolic stroke. POAF within seven days after cardiac surgery was associated with a three-fold increased risk for a thromboembolic stroke during hospital admission. Expeditious treatment of POAF may, therefore, reduce early stroke risk after cardiac surgery.

Oral anticoagulant use in patients with atrial fibrillation and mitral valve repair

Patients with atrial fibrillation (AF) who have undergone mitral valve repair are at risk for thromboembolic strokes. Prior to 2019, only vitamin K antagonists were recommended for patients with AF who had undergone mitral valve repair despite the introduction of direct oral anticoagulants (DOAC) in 2010. To characterize the use of anticoagulants in patients with AF who underwent surgical mitral valve repair (sMVR) or transcatheter mitral valve repair (tMVR). We performed a retrospective cohort analysis of patients with AF undergoing sMVR or tMVR between 04/2014 and 12/2018 using Optum's de-identified Clinformatics® Data Mart Database. We identified anticoagulants prescribed within 90 days of discharge from hospitalization. Overall, 1997 patients with AF underwent valve repair: 1560 underwent sMVR, and 437 underwent tMVR. The mean CHA2DS2-VASc score among all patients was 4.1 (SD 1.9). The overall use of anticoagulation was unchanged between 2014 (72.2%) and 2018 (70.0%) (P = .49). Among patients who underwent sMVR or tMVR between April 2014 and December 2018, the use of VKA therapy decreased from 62.9% to 32.1% (P < .01 for trend) and the use of DOACs increased from 12.4% to 37.3% (P < .01 for trend). Among patients with AF who underwent sMVR or tMVR between 2014 and 2018, roughly 30% of patients were not treated with any anticoagulant within 90 days of discharge, despite an elevated stroke risk in the cohort. The rate of DOAC use increased steadily over the study period but did not significantly increase the rate of overall anticoagulant use in this high-risk cohort.

Extracellular vesicles in atrial fibrillation and stroke

BackgroundAtrial fibrillation (AF) is associated with a 5-fold increased risk of thromboembolic stroke. Extracellular vesicles (EVs) convey pathophysiological information and are possible biomarkers for risk of stroke. MethodsEVs were measured in 836 patients with AF (of which 280 were stroke cases) selected from the ARISTOTLE trial and in a cohort of unselected 70 year old individuals (n = 1007, reference material). EVs from platelets, leukocytes, erythrocytes and inflammatory endothelial cells were measured using flow cytometry and a solid-phase proximity ligation assay. ResultsConcentrations of EVs were higher in the ARISTOTLE patients than in the PIVUS cohort for all the EV groups except EVs from endothelial cells (p < 0.0001). The distributions of the concentrations of the EVs were similar among the control group and the stroke cases for all of the sources of EVs in the ARISTOTLE study. EVs were modestly correlated with the levels of NT-ProBNP, Cystatin C, GDF-15 and D-dimer. Stronger correlations were found for platelet EVs as well as phosphatidyl serine positive EVs that were correlated with CD40 ligand in the ARISTOTLE study. Leukocyte EVs were correlated with IL-6 in both the ARISTOTLE and the PIVUS study, implicating them in different physiological processes. ConclusionsHigher levels of EVs were found in anticoagulated patients with AF and a higher risk of stroke than in a general population of similar age, possibly due to the high disease burden in AF patients. Our data with EVs representing a broad repertoire of activated blood cells in AF patients suggest that EVs are likely not a key mediator of occurrence of stroke in this population.

Аналіз ризиків інсульту, розвитку кровотеч та смерті у пацієнтів похилого віку з фібриляцією передсердь неклапанного генезу, які отримували різні пероральні антикоагулянти за програмою Medicare CША

Nonvitamin K antagonist oral anticoagulants (NOACs) are widely used in patients with nonvalvular atrial fibrillation. There were numerous studies in which NOACs were investigated and compared with warfarin; however, no randomized trials were performed to compare efficacy and safety of various NOACs with each other. We announce a cohort study of a large group of patients with nonvalvular atrial fibrillation who were allocated to warfarin (n = 183,318) or a standard dose of dabigatran (150 mg twice daily; n = 86,198), rivaroxaban (20 mg once daily; n = 106,389), or apixaban (5 mg twice daily; n = 73,039) under the program Medicare in the period from October 2010 to September 2015. Primary outcomes were stroke, bleeding and death. Hazard ratios (HR) and 95% confidence intervals (CI) for the outcomes were estimated using Cox proportional hazards regression. Each of the studied NOAC was compared with warfarin and with each other. All the subjects had similar baseline characteristics. Moreover, patient groups were balanced for all covariates (age, gender, comorbidities etc). Dabigatran, rivaroxaban, and apixaban were associated with lower risk of thromboembolic stroke, bleeding and death compared with warfarin, so their benefit-harm ratio was more favorable than that of warfarin. The risk of stroke was similar for all the studied NOACs, but the risk of bleeding and death was higher for rivaroxaban. This allows for the conclusion that dabigatran and apixaban had more favorable benefit-harm ratio than rivaroxaban.