Antithrombotic therapies in patients with prosthetic heart valves: guidelines translated for the clinician

Periprocedural Bridging Therapy in Patients With Mechanical Heart Valves

Mechanical heart valves (MHVs) are thrombogenic and require lifelong anticoagulation with vitamin K antagonists (VKAs) such as warfarin. Periprocedural bridging with unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) aims to reduce the risk of thromboembolic events in patients. Currently, there are no definitive class I recommendations for anticoagulation management in patients with MHVs. In this report, we present the case of a 77-year-old female who was perioperatively bridged with enoxaparin and subsequently developed an acute thrombus.

AGREE and ESA for Greenness Assessment of a Novel Validated RP-HPLC Method for Simultaneous Determination of Aspirin, Warfarin and Clopidogrel in Rat Plasma: Application to Pharmacokinetic Study of the Possible Interaction between the Three Drugs

The green profile of the developed method is assessed and compared with previously reported methods. Percutaneous coronary intervention is a procedure where a catheter is utilized to place a stent in order to facilitate opening of the blood vessels in the heart. Triple antithrombotic therapy includes oral anticoagulation as warfarin and dual antiplatelet therapy (composed of aspirin and clopidogrel bisulfate). The aim of the current study was to evaluate the pharmacokinetic parameters of ASP, WAR and CLP and to investigate the possible interaction between the three drugs upon co-administration in rats. A selective and precise RP-HPLC method was developed for the simultaneous determination of ASP, WAR and CLP in rat plasma. Pharmacokinetic study was conducted in rats that received ASP, WAR and CLP as an application of the developed method. From the statistical evaluation of the pharmacokinetic parameters, it was observed that the co-administration of ASP, WAR and CLP significantly increased the ASP and CLP bioavailability in rats. A significant drug-drug interaction was confirmed in the current study. The elevated Cmax of ASP and CLP upon the co-administration of ASP, WAR and CLP may explain the reported bleeding.

Mechanical Aortic Valve Thrombosis with Heart Failure Successfully Treated with Oral Anticoagulation: A Case Report

Background

The use of anticoagulation is mandatory for prevention of prosthetic valve thrombosis (PVT) worldwide, regardless of the valve type or position in the heart. In case a thrombosis causes symptomatic dysfunction, treatment usually includes the use of thrombolytic therapy or surgery. We report a case of PVT involving a patient with a mechanical aortic valve which was treated entirely with the use of anticoagulation therapy (warfarin).

Case Presentation

A 58-year-old man had an aortic valve replacement using a Carbomedics® mechanical valve due to severe aortic stenosis as a result of a calcific bicuspid native aortic valve. He was commenced on warfarin after surgery which was continued thereafter. He presented to our hospital after three years with shortness of breath at rest. On clinical examination, his condition was poor with a New York Heart Association functional classification of IV. He was in sinus rhythm and had an enlarged heart shadow on chest X-ray. Transesophageal echocardiography (TEE) revealed aortic valve regurgitation with vegetations on the anterior valve leaflet causing reduced hemi leaflet motility and a mean pressure gradient of 50 mmHg. Cinefluoroscopy revealed a dysfunctional mechanical valve leaflet. Surgery was at high risk of mortality due to the patient's clinical status and he was continued on warfarin therapy with close monitoring. Cinefluoroscopy and echocardiography done six months later revealed complete dissolution of thrombus and a normally functioning mechanical aortic valve.

Conclusion

Only a few cases of symptomatic, thrombotic mechanical aortic valve were entirely treated with anticoagulation only. Our patient is one such case who had resolution of symptoms and improvement on NYHA functional classification (IV to I).

Recurrent paraneoplastic cerebral hemorrhage in lung cancer: A case report

Cerebral hemorrhage management in a patient requiring anticoagulant therapy is a therapeutic challenge also due to the absence of guidelines that convincingly define the best therapeutic strategy. Although the occurrence of cerebral hemorrhage in a patient with anticoagulant therapy seems to make the bleeding etiology obvious, sometimes, it is better to reflect on other possible causes and set up an adequate diagnostic workup. Herein, we describe a case of a 73-year-old male patient with atrial fibrillation, mechanical heart valve, and pacemaker that experienced an ischemic minor stroke during steady anticoagulation therapy with recurrent intracerebral haemorrhages (ICHs).

Budget impact analysis of a bovine pericardial aortic bioprosthesis versus mechanical aortic valve replacement in adult patients with aortic stenosis in Romania

AIMS

An analysis of the budget impact of using a bovine pericardial aortic bioprosthesis (BPAB) or a mechanical valve (MV) in aortic stenosis (AS) patients in Romania.

MATERIALS AND METHODS

A decision-tree with a partitioned survival model was used to predict the financial outcomes of using either a BPAB (the Carpentier-Edwards Perimount Magna Ease Valve) or MV in aortic valve replacement (AVR) procedure over a 5-year period. The budget impact of various resource consumption including disabling strokes, reoperations, minor thromboembolic events, major bleeding, endocarditis, anticoagulation treatment and monitoring, and echocardiogram assessments were compared for both types of valves. One-way sensitivity analyses (OWSA) were conducted on the input costs and probabilities.

RESULTS

The use of BPAB compared to MV approaches budget neutrality due to incremental savings year-on-year. The initial surgical procedure and reoperation costs for BPAB are offset by savings in acenocoumarol use, disabling strokes, major bleeding, minor thromboembolic events, and anticoagulation complications. The cost of the initial procedure per patient is 460 euros higher for a BPAB due to the higher valve acquisition cost, although this is partially offset by a shorter hospital stay. The OWSA shows that the total procedure costs, including the hospital stay, are the primary cost drivers in the model.

LIMITATIONS

Results are limited by cost data aggregation in the DRG system, exclusion of costs for consumables and capital equipment use, possible underestimation of outpatient complication costs, age-related variations of event rates, and valve durability.

CONCLUSIONS

Adopting BPAB as a treatment option for AS patients in Romania can lead to cost savings and long-term economic benefits. By mitigating procedure costs and increasing anticoagulation treatment costs, BPAB offers a budget-neutral option that can help healthcare providers, policymakers, and patients alike manage the growing burden of AS in Romania.

A clinical conundrum: review of anticoagulation in pregnant women with mechanical prosthetic heart valves

In South Africa, maternal mortality from cardiovascular disease remains high. The recent Saving Mothers report 2017-2019 from the Confidential Enquiries into Maternal Deaths revealed that indirect maternal death from medical and surgical disorders is the fourth commonest cause of maternal death, accounting for 16.9% of deaths, with cardiac disease accounting for one-third of this. The burden of rheumatic heart disease (RHD) is a significant contributor to maternal morbidity and mortality. The true burden is unknown due to limited data. The natural history of RHD confers additional risk as many cases may remain undiagnosed, with first presentation occurring during pregnancy. This undiagnosed subset of women may be the result of poor accessibility to healthcare facilities and primary healthcare interventions for acute rheumatic fever. RHD causes progressive damage to the heart valves, especially the left-sided valves, which eventually require surgical correction with mechanical prosthetic valves.

Endothelial Progenitor Cell-Based in vitro Pre-Endothelialization of Human Cell-Derived Biomimetic Regenerative Matrices for Next-Generation Transcatheter Heart Valves Applications

Hemocompatibility of cardiovascular implants represents a major clinical challenge and, to date, optimal antithrombotic properties are lacking. Next-generation tissue-engineered heart valves (TEHVs) made from human-cell-derived tissue-engineered extracellular matrices (hTEMs) demonstrated their recellularization capacity in vivo and may represent promising candidates to avoid antithrombotic therapy. To further enhance their hemocompatibility, we tested hTEMs pre-endothelialization potential using human-blood-derived endothelial-colony-forming cells (ECFCs) and umbilical vein cells (control), cultured under static and dynamic orbital conditions, with either FBS or hPL. ECFCs performance was assessed via scratch assay, thereby recapitulating the surface damages occurring in transcatheter valves during crimping procedures. Our study demonstrated: feasibility to form a confluent and functional endothelium on hTEMs with expression of endothelium-specific markers; ECFCs migration and confluency restoration after crimping tests; hPL-induced formation of neo-microvessel-like structures; feasibility to pre-endothelialize hTEMs-based TEHVs and ECFCs retention on their surface after crimping. Our findings may stimulate new avenues towards next-generation pre-endothelialized implants with enhanced hemocompatibility, being beneficial for selected high-risk patients.

Management of Life-Threatening Bleeding in Patients With Mechanical Heart Valves

Valvular heart disease is common in the United States, with a number of patients undergoing valve replacement procedures every year. The two types of valve prostheses include mechanical and bioprosthetic valves. Mechanical heart valves require lifelong anticoagulation with vitamin K antagonists like warfarin. The clinicians are often faced with the dilemma of major bleeding episodes such as intracranial hemorrhage or gastrointestinal bleeding in these patients. The management includes reversing warfarin-induced coagulopathy with vitamin K supplementation, fresh frozen plasma, or prothrombin complex concentrate (PCC), with PCC being the treatment of choice. With regard to the safe resumption of anticoagulation, guidelines are silent, and data is limited to case reports/series. This article reviews the present literature for the management of bleeding in patients with mechanical heart valves and the safe duration for holding off anticoagulation with minimal risk of valve thrombosis/thromboembolism.

Effects of a Personalized Nurse-Led Educational Program for New Patients Receiving Oral Anticoagulant Therapy after Mechanical Heart Valve Prosthesis Implantation on Adherence to Treatment

Background

Life-long anticoagulant therapy is mandatory for patients who undergo heart valve replacement with implantation of a mechanical prosthesis. The aim of this study was to investigate the effects of a nurse-led patient educational program concerning oral anticoagulant therapy intake after heart valve replacement surgery on patients’ knowledge of important parameters of anticoagulant administration.

Methods

In this single-center study, 200 patients who underwent surgical implantation of a mechanical prosthesis were divided into 2 groups. The control group received the basic education concerning oral anticoagulants, while the intervention group received a personalized educational program.

Results

Personalized education was correlated with a better regulation of therapeutic international normalized ratio (INR) levels and adequate knowledge among patients. Therapeutic levels of INR were achieved in 45% of the patients during the first month, 71% in the third month, and 89% in the sixth month after discharge in the intervention group, compared to 25%, 47%, and 76% in the control group, respectively. Patients’ satisfaction with the information was higher in the intervention group than in the control group. The percentage of satisfaction reached 80% for the intervention group versus 37% for the patients of the control group.

Conclusion

The implementation of the nurse-led educational programs was associated with improved clinical results and increased adherence to oral anticoagulant treatment.

Risks and benefits of concurrent treatment with antiplatelet and anticoagulation therapy in post-op bioprosthetic aortic valve replacement patients

BACKGROUND AND AIM

Among patients receiving surgical bioprosthetic aortic valve replacement (bAVR), there is an elevated risk of thromboembolic events postoperatively. However, the risks and benefits of varying anticoagulation strategies remain controversial. The aim of this study is to compare the risks and benefits of aspirin monotherapy to aspirin plus warfarin ("concurrent therapy") in patients receiving bAVR.

METHODS

A retrospective cohort study was conducted using patients' data from Kaiser Permanente Northern California, including those who underwent bAVR with or without coronary artery bypass grafting between 2009 and 2018. Patients were identified as having been discharged with aspirin only or concurrent therapy. The outcomes were mortality, thromboembolic events, and clinically relevant bleeding during a 6-month follow-up. The event rates were compared using the Kaplan-Meier method. Multivariable survival analysis, incorporating propensity scores, was used to estimate adjusted hazard ratios (aHRs) for each outcome.

RESULTS

The cohort consisted of 3047 patients. Approximately 58% of patients received aspirin only and 42% received concurrent therapy. Patients who received concurrent therapy were more likely to be older, have hypertension, previous stroke, and longer hospital stays. After adjustment using multivariable analysis, concurrent therapy was associated with a higher risk of clinically relevant bleeding (aHR, 2.33; 95% confidence interval, 1.67-3.25). There was no significant difference in the risk of thromboembolic events or mortality between the two groups.

CONCLUSION

Patients who underwent bAVR and were discharged on concurrent therapy compared to aspirin only had a significantly increased risk of bleeding without a significant difference in thromboembolic events.

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.

Optimal oral anticoagulant therapy in Chinese patients with mechanical heart valves

BACKGROUND

The oral administration of anticoagulants is an effective means of preventing thromboembolic complications in patients implanted with mechanical valves. This treatment strategy, however, entails a dose-dependent in the risk of hemorrhage that is a cause for concern in China. As such, in this study, we sought to better determine what the ideal oral anticoagulant therapy intensity is in a Chinese population of patients implanted with mechanical valves.

METHODS

In the present observational cohort study, we observed the outcomes of eligible enrolled patients that had been implanted with St. Jude Medical prosthetic valves and who had been treated at our institution from 2013 onwards. All enrolled patients were followed for between 1 and 6 years through outpatient visits or telephone interviews following discharge. Study endpoints included instances of thromboembolism and major hemorrhage. We calculated the international normalized ratio (INR)-specific incidence of such adverse events as a means of determining optimal anticoagulant therapeutic intensity in patients with these bileaflet mechanical valve prostheses.

RESULTS

In total this study enrolled 3176 patients, of whom 3017 were followed for 12,746.08 total person-years (4.22 mean years per patient), while the remaining 159 patients (5%) were lost during follow-up. A total of 182 patients suffered from adverse events, with a roughly 1.43% annual incidence rate of such adverse events (95% confidence interval [CI], 1.22-1.64). Of these, 54 patients suffered from episodes of major bleeding (0.42% per patient-year, 95% CI, 0.31-0.53), while 131 suffered from thromboembolism (1.03% per patient-year, 95% CI, 0.85-1.21). Based on these analyses, we determined that the ideal low-intensity anticoagulant treatment regimen for patients with bileaflet mechanical heart valve prostheses was an INR between 1.5 and 2.5. In those patients that had undergone aortic valve replacement (AVR), the optimal INR was between 1.5 and 2.0 regardless of any thromboembolism risk factors in these patients. In contrast, in patients that had undergone mitral valve replacement (MVR) who were not at risk for thromboembolism, the optimal INR was between 1.5 and 2.0, whereas in those at risk of thromboembolism the optimal INR was between 2.0 and 2.5. The ideal anticoagulant intensity in patients undergoing both AVR and MVR (DVR) was the same as in patients undergoing MVR alone.

CONCLUSIONS

In order to achieve optimal outcomes by maintaining effective anticoagulant dosing while entailing minimal risk in Chinese patients that have undergone a bileaflet mechanical valve replacement, the target INR range should be between 1.5 and 2.5, with the final intensity of this anticoagulant regimen being determined based on a given patient's risk of thromboembolism.

Effect of Self-Management Program on Self-efficacy and Medication Adherence in Patients with Mechanical Heart Valve: a Randomized Clinical Trial

Introduction: Patients with mechanical heart valve need anticoagulant therapy to prevent thrombotic events. The treatment interacts with some foods and drugs. The aim was to evaluate the effect of self- management program on self-efficacy and medication adherence in patients with mechanical heart valve. Methods: This was a randomized controlled trial. eighty eligible patients, with the ability to read and speak in Farsi, aged between 15 to 60, were included in the study from the cardiac surgery clinic in Imam Khomeini hospital affiliated to Tehran University of Medical Sciences (Tehran, Iran) and randomly allocated to intervention and control groups. The participants had no history of psychiatric disorders, had undergone valve replacement surgery at least one year before the study, and were being treated with Warfarin. The intervention was a combination of 2 one- hour self-management education via small groups with 3 to 5 members, self-management educational booklets, and weekly call follow- ups for 8 weeks about 10- 15 minutes. The control group received no intervention. Self- efficacy was the primary outcome and medication adherence, Prothrombin Time (PT), and International Normalized Ratio (INR) were secondary outcomes. Data were analyzed using spss13. Results: Although the mean of self-efficacy and medication adherence, PT, and INR values were not different between the two groups at baseline, they improved significantly following the program. Conclusion: Self-management program had a positive effect on self-efficacy and medication adherence of patients with mechanical heart valve.

Influence of warfarin on cardiac and cerebrovascular events following bioprosthetic aortic valve replacement: A nationwide cohort study

OBJECTIVE

The need for anticoagulation treatment following bioprosthetic aortic valve replacement remains controversial. We investigated the associations of warfarin treatment with the risks of major adverse cardiac and cerebrovascular events, including mortality, bleeding incidents, and reoperation requirement after bioprosthetic aortic valve replacement surgery.

METHODS

We identified 1086 patients who received first bioprosthetic aortic valve replacement between 2001 and 2010 using Taiwan's National Health Insurance Database. Patients were excluded for prior use of warfarin, warfarin use for >3 months, dual valve procedures, prior valve surgeries, or concomitant surgeries. Enrolled patients were divided into 2 groups according to whether they were warfarin-naïve or received warfarin for <3 months postsurgery. After propensity score matching, 282 patients not receiving warfarin were matched to 282 patients receiving warfarin for <3 months. Patients were followed-up for minimum 36 months.

RESULTS

Patients receiving warfarin were younger and showed less frequent kidney disease than those who did not use warfarin. The warfarin group demonstrated a gross decrease in major adverse cardiac and cerebrovascular events. Patients receiving warfarin for <30 days were at an even lower risk for major adverse cardiac and cerebrovascular events than those treated for ≥30 days. No significant difference in bleeding or reoperation risk was observed between warfarin users and warfarin nonusers. Similar findings remained after propensity-score matching but the benefit of short-term warfarin use diminished in a younger population.

CONCLUSIONS

Short-term use of postoperative warfarin (especially <30 days) following bioprosthetic aortic valve replacement may be associated with a reduction in MACCE compared with nonuse.

Ischemic and bleeding outcomes of triple therapy in patients on chronic anticoagulation undergoing percutaneous coronary intervention: A meta-analysis of randomized trials

BACKGROUND

Triple therapy (TT) that includes oral anticoagulation and dual antiplatelet therapy is recommended in patients who are on chronic anticoagulation and undergo percutaneous coronary intervention (PCI). The randomized clinical trials (RCTs) comparing the effectiveness and safety of TT compared to double therapy (DT), which consists of an oral anticoagulation and one of the P2Y12 inhibitors, have shown increased risk of bleeding; however, none of the individual studies were powered to show a difference in ischemic outcomes. To compare the clinical outcomes of TT and DT, we performed this meta-analysis of RCTs.

METHODS

Electronic search of PubMed, EMBASE and Cochrane CENTRAL databases was performed for RCTs comparing TT and DT in patients who were on oral anticoagulation (Vitamin K antagonist or non-vitamin K antagonist oral anticoagulant) who underwent PCI. All-cause and cardiovascular mortality, myocardial infarction (MI), stroke, stent thrombosis (ST) and TIMI major and minor bleeding were the major outcomes.

RESULTS

An analysis of 5 trials including 10,592 total patients showed that TT, compared to DT, resulted in non-significant difference in risk of all-cause [odds ratio (OR); 1.14;95% confidence interval (CI):(0.80-1.63); P = 0.46) and cardiovascular mortality [1.43(0.58-3.36); P = 0.44], MI [0.88 (0.64-1.21); P = 0.42], stroke [1.10(0.75-1.62); P = 0.63] and ST [0.82(0.46-1.45); P = 0.49]. TT, compared to DT resulted in higher risk of TIMI major bleeding [1.61(1.09-2.37); P = 0.02], TIMI minor bleeding [1.85(1.23-2.79); P = 0.003] and TIMI major and minor bleeding [1.81 (1.38-2.38); P < 0.0001; I2 = 52%].

CONCLUSION

Compared to DT, the patients receiving TT are at a higher risk of major and minor bleeding with no survival benefit or impact on thrombotic outcomes.

Recurrent Hemorrhagic Conversion of Ischemic Stroke in a Patient with Mechanical Heart Valve: A Case Report and Literature Review

The authors present a unique case of recurrent stroke, discovered to be secondary to hemorrhagic conversion of microemboli from a mechanical aortic valve despite anticoagulation with Coumadin. The complexity of this case was magnified by the patient’s young age, a mechanical heart valve (MHV), and a need for anticoagulation to maintain MHV patency in a setting of potentially life-threatening intracranial hemorrhage. Anticoagulant and antiplatelet therapy are risk factors for hemorrhagic conversion post-cerebral ischemia; however, the pathophysiology underlying endothelial cell dysfunction causing red blood cell extravasation is an active area of basic and clinical research. The need for randomized clinical trials to aid in the creation of standardized treatment protocol continues to go unmet. Consequently, there is marked variation in therapeutic approaches to treating intracranial hemorrhage in patients with an MHV. Unfortunately, patients with an MHV are considered at high thromboembolic (TE) risk, and these patients are often excluded from clinical trials of acute stroke due to their increased TE potential. The authors feel this case represents an example of endothelial dysfunction secondary to microthrombotic events originating from an MHV, which caused ischemic stroke with hemorrhagic conversion complicated by the need for anticoagulation for an MHV. This case offers a definitive treatment algorithm for a complex clinical dilemma.

Impact of postoperative duration of Aspirin use on longevity of bioprosthetic pulmonary valve in patients who underwent congenital heart disease repair

Purpose

Generally, aspirin is used as a protective agent against thrombogenic phenomenon after pulmonary valve replacement (PVR) using a bioprosthetic valve. However, the appropriate duration of aspirin use is unclear. We analyzed the impact of postoperative duration of aspirin use on the longevity of bioprosthetic pulmonary valves in patients who underwent repair for congenital heart diseases.

Methods

We retrospectively reviewed the clinical data of 137 patients who underwent PVR using a bioprosthetic valve between January 2000 and December 2003. Among these patients, 89 were included in our study and divided into groups I (≤12 months) and II (>12 months) according to duration of aspirin use. We analyzed echocardiographic data from 9 to 11 years after PVR. Pulmonary vale stenosis and regurgitation were classified as mild, moderate, or severe.

Results

The 89 patients consisted of 53 males and 36 females. Their mean age was 14.3±8.9 years (range, 2.6–48 years) and body weight was 37.6±14.7 kg (range, 14–72 kg). The postoperative duration of aspirin use was 7.3±2.9 months in group I and 32.8±28.4 months in group II. However, no significant difference in sex ratio, age, body weight, type of bioprosthetic valve, and number of early redo-PVRs. In the comparison of echocardiographic data about 10 years later, no significant difference in pulmonary valve function was found. The overall freedom rate from redo-PVR at 10 years showed no significant difference (P=0.498).

Conclusion

Our results indicated no benefit from long-term aspirin medication (>6 months) in patients who underwent PVR with a bioprosthetic valve.

Are anticoagulant independent mechanical valves within reach-fast prototype fabrication and in vitro testing of innovative bi-leaflet valve models

BACKGROUND

Exploration for causes of prosthetic valve thrombogenicity has frequently focused on forward or post-closure flow detail. In prior laboratory studies, we uncovered high amplitude flow velocities of short duration close to valve closure implying potential for substantial shear stress with subsequent initiation of blood coagulation pathways. This may be relevant to widely accepted clinical disparity between mechanical and tissue valves vis-à-vis thrombogenicity. With a series of prototype bi-leaflet mechanical valves, we attempt reduction of closure related velocities with the objective of identifying a prototype valve with thrombogenic potential similar to our tissue valve control. This iterative design approach may find application in preclinical assessment of valves for anticoagulation independence.

METHODS

Tested valves included: prototype mechanical bi-leaflet BVs (n=56), controls (n=2) and patented early prototype mechanicals (n=2) from other investigators. Pulsatile and quasi-steady flow systems were used for testing. Projected dynamic valve area (PDVA) was measured using previously described novel technology. Flow velocity over the open and closing periods was determined by volumetric flow rate/PDVA. For the closed valve interval, use was made of data obtained from quasi-steady back pressure/flow tests. Performance was ranked by a proposed thrombogenicity potential index (TPI) relative to tissue and mechanical control valves.

RESULTS

Optimization of the prototype valve designs lead to a 3-D printed model (BV3D). For the mitral/aortic site, BV3D has lower TPI (1.10/1.47) relative to the control mechanical valve (3.44/3.93) and similar to the control tissue valve (ideal TPI ≤1.0).

CONCLUSIONS

Using unique technology, rapid prototyping and thrombogenicity ranking, optimization of experimental valves for reduced thrombogenic potential was expedited and simplified. Innovative mechanical valve configurations were identified that merit consideration for further development which may bring the anti-coagulation independent mechanical valve within reach.

Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients

Introduction

Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce.

Objective

To investigate the arrhythmia subtype of atrial fibrillation and flutter patients in the emergency setting and compare the clinical profile, thromboembolic risk and anticoagulants use.

Methods

Cross-sectional retrospective study, with data collection from medical records of every patient treated for atrial fibrillation and flutter in the emergency department of Instituto de Cardiologia do Rio Grande do Sul during the first trimester of 2012.

Results

We included 407 patients (356 had atrial fibrillation and 51 had flutter). Patients with paroxysmal atrial fibrillation were in average 5 years younger than those with persistent atrial fibrillation. Compared to paroxysmal atrial fibrillation patients, those with persistent atrial fibrillation and flutter had larger atrial diameter (48.6 ± 7.2 vs. 47.2 ± 6.2 vs. 42.3 ± 6.4; p < 0.01) and lower left ventricular ejection fraction (66.8 ± 11 vs. 53.9 ± 17 vs. 57.4 ± 16; p < 0.01). The prevalence of stroke and heart failure was higher in persistent atrial fibrillation and flutter patients. Those with paroxysmal atrial fibrillation and flutter had higher prevalence of CHADS2 score of zero when compared to those with persistent atrial fibrillation (27.8% vs. 18% vs. 4.9%; p < 0.01). The prevalence of anticoagulation in patients with CHA2DS2-Vasc ≤ 2 was 40%.

Conclusions

The population in our registry was similar in its comorbidities and demographic profile to those of North American and European registries. Despite the high thromboembolic risk, the use of anticoagulants was low, revealing difficulties for incorporating guideline recommendations. Public health strategies should be adopted in order to improve these rates.

Implications of using different methods to characterise anticoagulant control in patients with second generation mechanical heart valve prostheses

OBJECTIVE

Characterisation of anticoagulant control is fundamental to investigations of its association with clinical outcome. Anticoagulant control depends on several factors. This paper aims to illustrate the implications of different methods for measuring and analysing anticoagulant control in patients with second generation mechanical heart valve prostheses.

METHODS

International normalised ratio (INR) data collected during the 10-year follow-up of a randomised controlled trial were analysed. We considered the influence of: 3 different target INR ranges; anticoagulant control expressed as the proportion of INR readings (PoR) vs. anticoagulant control follow-up time (PoT); 3 ways of describing the profile of anticoagulant control over time.

RESULTS

Different target INR ranges dramatically influenced derived measures of anticoagulant control; the PoT within the target range varied from 88% for the widest to 28% for narrowest range. Overall distributions of PoR and PoT observations were similar but differed by up to ± 20% for individuals; PoT exceeded PoR when control was good but was less than PoR when control was poor. Classifying PoT outside the target range showed that widely varying combinations of PoT too high and too low are possible across individuals.

CONCLUSIONS

Researchers' choices about methods for measuring and quantifying anticoagulant control markedly influence the values derived from INR readings. The use of different methods across studies makes it difficult or impossible to compare findings and to establish an evidence base for clinical practice. Methods for quantifying anticoagulant control should be standardised.

Drug adherence in patients taking oral anticoagulation therapy

Oral anticoagulation has proven to reduce mortality and morbidity of thromboembolic events. One of the most important determinants of the effectiveness and safety of anticoagulation therapy is the adherence to the prescribed therapy. Vitamin K antagonists are characterized by under-utilization, a narrow therapeutic window and multiple food and drug interactions which contribute to a variable dose-response relationship with the risk of insufficient protection and/or increased bleeding risk. The "new" direct oral anticoagulants have demonstrated equal or superior protection and reduced bleeding risks compared to warfarin and are easier to use because of fixed dosing without monitoring of anticoagulation. Controlling of adherence to the direct oral anticoagulants is difficult. Therefore, continuous and regular medication intake represents a pre-requisite for achieving optimal protection. The present review aims to give an overview about the factors that affect drug adherence in patients taking oral anticoagulation drugs and discusses strategies to improve drug adherence.

Assessment of the adherence of cardiologists to guidelines for the treatment of atrial fibrillation

BACKGROUND

No local studies evaluating the knowledge of cardiologists on the management of atrial fibrillation (AF) and their adherence to these guidelines are available.

OBJECTIVE

To evaluate the knowledge of cardiologists on the guidelines and clinical practices for the treatment of AF, correlating it to the time since medical graduation.

METHODS

Cross-sectional study randomly including cardiologists affiliated to the Society of Cardiology of the State of Rio Grande do Sul (Sociedade de Cardiologia do Estado do Rio Grande do Sul - SOCERGS). The physicians were divided into two groups, according to time since graduation: those graduated for more (G1) or less (G2) than 25 years.

RESULTS

Of the 859 SOCERGS members, 150 were interviewed, and six refused to participate in the study. G1 comprised 71 physicians, and G2, 73. Differences were observed in regard to the following variables: use of betablockers as the first-choice drug for the control of AF response in 59.2% (G1) vs 91.8% (G2) (p<0.0001); use of digoxin as the preferred drug for the control of AF response in 19.7% (G1) vs 0% (G2) (p< 0.0001); warfarin as the preferred anticoagulant in 71.8% (G1) vs 93.2% (G2) (p=0.009); application of a risk score for anticoagulation in 73.2% (G1) vs 87.7% (G2) (p=0.02). In questions regarding the knowledge about the Brazilian Society of Cardiology's guideline for AF, the overall percentage of right answers was 82.3%.

CONCLUSION

Most of the clinical measures regarding the management of AF comply with the guidelines, and the clinical practice differs according with the time since graduation.

Highlights from the IV International Symposium of Thrombosis and Anticoagulation (ISTA), October 20-21, 2011, Salvador, Bahia, Brazil

To discuss and share knowledge about advances in the care of patients with thrombotic disorders, the Fourth International Symposium of Thrombosis and Anticoagulation was held in Salvador, Bahia, Brazil, from October 20-21, 2011. This scientific program was developed by clinicians for clinicians and was promoted by three major clinical research institutes: the Brazilian Clinical Research Institute, the Duke Clinical Research Institute of the Duke University School of Medicine, and Hospital do Coração Research Institute. Comprising 2 days of academic presentations and open discussion, the symposium had as its primary goal to educate, motivate, and inspire internists, cardiologists, hematologists, and other physicians by convening national and international visionaries, thought-leaders, and dedicated clinician-scientists. This paper summarizes the symposium proceedings.

Thrombosis of A Prosthetic Mitral Valve After Withdrawal of Phenprocoumon Therapy

Patients with prosthetic heart valves require lifelong oral anticoagulant therapy based on vitamin K antagonists. These patients may need interruption of their anticoagulant therapy if they have to undergo surgery. The clinical challenge is to identify patients who can safely undergo surgery while continuing their vitamin K antagonist treatment and those who have to take short-acting heparin as part of a bridging therapy. Here we present a case of a patient with a prosthetic mitral valve whose oral anticoagulant therapy was unnecessarily discontinued by the GP prior to an upcoming cataract surgery. As a result, the patient developed thrombosis of the prosthetic mitral valve which needed to be surgically replaced.