Self-management of oral anticoagulation therapy improves long-term survival in patients with mechanical heart valve replacement

Self-management of patients with heart valve replacement and its clinical outcomes: a systematic review

Introduction

For patients with heart valve replacement, self-management can play an essential role in the management of their condition.

Aim

This review aimed to identify the aspects of self-management and its clinical outcomes in patients with heart valve replacement.

Material and methods

In this systematic review, the peer-reviewed research literature on self-management of patients with heart valve replacement was assessed. Since May 2020, the PubMed, Scopus, and web of science databases were searched regardless of time and language limitations. The eligibility of the articles was assessed by title or abstract according to the search strategy. Article selection was applied regarding to inclusion and exclusion criteria. Also, article screening was conducted by 2 independent authors.

Results

Twenty-five studies were considered in this systematic review. For inclusion, the self-management of patients had to have prerequisites, appropriate training, and be applicable in the aspects of anticoagulation therapy self-management, international normalized ratio (INR) self-testing, low-dose INR self-management, and heart valve function self-monitoring. In this method, through proper management of INR levels and anticoagulation therapy, the complications rate could be reduced and the patients would be able to diagnose functional disorders in the early stages by monitoring the valve function. This procedure was able to prevent the progression of complications.

Conclusions

Self-management is an applicable protocol in the field of anticoagulation therapy, INR control, low-dose INR management, and the monitoring of cardiac valve function. This protocol could improve the quality of treatment for these patients through upgrading the care standards.

Anticoagulation and Antiplatelet Strategies After On-X Mechanical Aortic Valve Replacement

BACKGROUND

The burden oral anticoagulation is a limitation of mechanical valve prostheses.

OBJECTIVES

The aim of this study was to test whether patients could be safely managed with dual-antiplatelet therapy (DAPT) (aspirin 325 mg and clopidogrel 75 mg) or lower warfarin after On-X mechanical aortic valve replacement (mAVR).

METHODS

PROACT (Prospective Randomized On-X Anticoagulation Trial) (n = 576) is a multicenter (41 sites) noninferiority trial. From June 2006 through February 2014, 201 patients ≥18 years of age without thromboembolic risk factors undergoing mAVR were randomized to receive DAPT (n = 99) or standard warfarin plus aspirin (n = 102) 3 months after mAVR (low-risk arm). From June 2006 through October 2009, 375 patients with 1 or more thromboembolic risk factors were also randomized to lower intensity warfarin plus aspirin (international normalized ratio 1.5 to 2.0; n = 185) or standard warfarin plus aspirin (international normalized ratio 2.0 to 3.0; n = 190) 3 months after mAVR (high-risk arm).

RESULTS

The low-risk arm was terminated for excess cerebral thromboembolic events (3.12% per patient-year vs. 0.29% per patient-year, p = 0.02) in the DAPT group at up to 8.8-year follow-up (631.6 patient-years), with no differences in bleeding or all-cause mortality. High-risk arm patients experienced significantly lower major (1.59% per patient-year vs. 3.94% per patient-year, p = 0.002) and minor (1.27% per patient-year vs. 3.49% per patient-year, p = 0.002) bleeding up to 8.7-year follow-up (2,035.2 patient-years), with no differences in thromboembolism (0.42% per patient-year vs. 0.09% per patient-year, p = 0.20) and all-cause mortality.

CONCLUSIONS

DAPT was associated with higher rates of thromboembolism and valve thrombosis compared with control in the low-risk arm. International normalized ratios were safely maintained at 1.5 to 2.0 in high-risk patients, without differences in mortality or thromboembolic complications. (Randomized On-X Anticoagulation Trial [PROACT]; NCT00291525).

The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT): Lower is better, but is it good enough?

Due to their durability, mechanical prostheses are frequently used for aortic valve replacement (AVR) in young adults. However, these valves are thrombogenic and require lifelong anticoagulation. Over the last few decades, efforts have been made towards the lowering of INR targets in an effort to reduce bleeding events without influencing the thromboembolic risk. The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT) was designed to compare standard versus low anticoagulation targets in high-risk patients undergoing mechanical AVR with the ON-X prosthesis.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy

BACKGROUND

Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE).

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 25 recommendations and 2 good practice statements to optimize management of patients receiving anticoagulants.

CONCLUSIONS

Strong recommendations included using patient self-management of international normalized ratio (INR) with home point-of-care INR monitoring for vitamin K antagonist therapy and against using periprocedural low-molecular-weight heparin (LMWH) bridging therapy. Conditional recommendations included basing treatment dosing of LMWH on actual body weight, not using anti-factor Xa monitoring to guide LMWH dosing, using specialized anticoagulation management services, and resuming anticoagulation after episodes of life-threatening bleeding.

Telemonitoring of left-ventricular assist device patients-current status and future challenges

E-health, especially telemedicine, has undergone a remarkably dynamic development over the past few years. Most experience is currently in the field of telemedical care for heart failure (HF) patients. However, HF patients with an implanted left-ventricular assist device (LVAD) have been more or less excluded from consistent telemonitoring until now. And yet, continual monitoring would be very significant for this patient group because of the complexity of its aftercare, requiring steady control of various parameters (device-related parameters, vital parameters, coagulation parameters, etc.). With timely action, severe and costly complications like pump thromboses and driveline infections could be detected early on or even avoided completely. This paper describes the potential of telemonitoring in LVAD patients, as well as its first clinical implementation according to the available literature. It also describes the requirements for a complete telemonitoring of LVAD patients, facilitating the advancement of this form of continual monitoring to a clinical standard which would increase the quality of aftercare for this very special patient collective enormously.

Anticoagulation for prosthetic heart valves: unresolved questions requiring answers

PURPOSE OF REVIEW

The efficacy of anticoagulation for valvular prostheses is the result of a delicate balance between the risk of thromboembolic (TE) events and bleeding. Here, we review data on anticoagulation for valve prostheses with a focus on clinical trials that address key unanswered questions.

RECENT FINDINGS

There are several unanswered questions in the field of prosthetic valve anticoagulation, including: optimal TE prophylaxis in the short term for bioprostheses, optimal TE prophylaxis following transcatheter aortic valve implantation, the safety and efficacy of lower levels of anticoagulation with the bileaflet mechanical prosthesis, the role of aspirin for patients with mechanical prostheses, and the management of anticoagulation for mechanical valves in pregnancy. Other areas of study include the role, if any, of nonwarfarin oral anticoagulants for prosthetic TE prophylaxis as well as self-INR monitoring. Finally, we briefly mention studies of newer anticoagulants, such as novel vitamin K antagonists and antisense oligonucleotides, that are on the horizon.

SUMMARY

Optimal antithrombotic management is a key issue for patients with valvular prostheses, and the publication of recent trials has provided much-needed guidance. We highlight areas of progress, in addition to the major unanswered questions for which well-designed, prospective clinical trials are forthcoming.

Plasma Vitamin K1 Levels in Italian Patients Receiving Oral Anticoagulant Therapy for Mechanical Heart Prosthesis: A Case-Control Study

BACKGROUND

Oral anticoagulant therapy (OAT) with a vitamin K antagonist (VKA) is the choice of treatment for preventing thromboembolism in patients with mechanical heart valve prosthesis (MHP). The percentage of time in the therapeutic range (TTR%) expresses the OAT quality. We planned a case-control study in order to determine vitamin K1 plasmatic concentrations in MHP patients and to correlate these with TTR%.

MATERIALS AND METHODS

Of 756 MHP patients receiving OAT, 125 patients (61 younger than 65 years, and 64 older than 65 years) and 120 healthy blood donors, matched for sex and age, were enrolled in the study. All subjects completed a living questionnaire regarding diet, and underwent blood collection. Vegetable and fruit intake was categorized as optimal or suboptimal, and the high-performance liquid chromatography method was used to determine vitamin K1 levels.

RESULTS

Neither the patients nor controls had been taking vitamin supplements prior to the start of the study. The median vitamin K1 level was 290 pg/mL in 72 controls with optimal intake, and 274 pg/mL in 48 controls with suboptimal intake, while the median vitamin K1 level in MHP patients with optimal intake was 409 pg/mL, significantly higher (p < 0.001) than the 133.5 pg/mL in patients with suboptimal intake. Vitamin K1 concentration in MHP patients appears to be linked to an age-related threshold: in patients younger than 65 years of age, the median vitamin K1 level was 431 pg/mL, significantly higher (p < 0.05) than the 290 pg/mL in patients older than 65 years of age. No clear relation was found between vitamin K1 levels and TTR% (Pearson = 0.14). However, patients with vitamin K1 >160 pg/mL showed a TTR% >60 %. Among patients younger than 65 years, subjects with vitamin K1 >160 pg/mL showed a median TTR of 66 %, this being significantly higher (p < 0.001) than the 46 % level shown by patients with vitamin K1 <160 pg/mL.

CONCLUSIONS

Vitamin K1 concentrations in MHP patients seem to be related to both diet and age.

Self-monitoring and self-management of oral anticoagulation

BACKGROUND

The introduction of point-of-care devices for the management of patients on oral anticoagulation allows self-testing by the patient at home. Patients who self-test can either adjust their medication according to a pre-determined dose-INR (international normalized ratio) schedule (self-management), or they can call a clinic to be told the appropriate dose adjustment (self-monitoring). Increasing evidence suggests self-testing of oral anticoagulant therapy is equal to or better than standard monitoring. This is an updated version of the original review published in 2010.

OBJECTIVES

To evaluate the effects on thrombotic events, major haemorrhages, and all-cause mortality of self-monitoring or self-management of oral anticoagulant therapy compared to standard monitoring.

SEARCH METHODS

For this review update, we re-ran the searches of the Cochrane Central Register of Controlled Trials (CENTRAL), 2015, Issue 6, the Cochrane Library, MEDLINE (Ovid, 1946 to June week 4 2015), Embase (Ovid, 1980 to 2015 week 27) on 1 July 2015. We checked bibliographies and contacted manufacturers and authors of relevant studies. We did not apply any language restrictions .

SELECTION CRITERIA

Outcomes analysed were thromboembolic events, mortality, major haemorrhage, minor haemorrhage, tests in therapeutic range, frequency of testing, and feasibility of self-monitoring and self-management.

DATA COLLECTION AND ANALYSIS

Review authors independently extracted data and we used a fixed-effect model with the Mantzel-Haenzel method to calculate the pooled risk ratio (RR) and Peto's method to verify the results for uncommon outcomes. We examined heterogeneity amongst studies with the Chi(2) and I(2) statistics and used GRADE methodology to assess the quality of evidence.

MAIN RESULTS

We identified 28 randomised trials including 8950 participants (newly incorporated in this update: 10 trials including 4227 participants). The overall quality of the evidence was generally low to moderate. Pooled estimates showed a reduction in thromboembolic events (RR 0.58, 95% CI 0.45 to 0.75; participants = 7594; studies = 18; moderate quality of evidence). Both, trials of self-management or self-monitoring showed reductions in thromboembolic events (RR 0.47, 95% CI 0.31 to 0.70; participants = 3497; studies = 11) and (RR 0.69, 95% CI 0.49 to 0.97; participants = 4097; studies = 7), respectively; the quality of evidence for both interventions was moderate. No reduction in all-cause mortality was found (RR 0.85, 95% CI 0.71 to 1.01; participants = 6358; studies = 11; moderate quality of evidence). While self-management caused a reduction in all-cause mortality (RR 0.55, 95% CI 0.36 to 0.84; participants = 3058; studies = 8); self-monitoring did not (RR 0.94, 95% CI 0.78 to 1.15; participants = 3300; studies = 3); the quality of evidence for both interventions was moderate. In 20 trials (8018 participants) self-monitoring or self-management did not reduce major haemorrhage (RR 0.95, 95% CI, 0.80 to 1.12; moderate quality of evidence). There was no significant difference found for minor haemorrhage (RR 0.97, 95% CI 0.67 to 1.41; participants = 5365; studies = 13). The quality of evidence was graded as low because of serious risk of bias and substantial heterogeneity (I(2) = 82%).

AUTHORS' CONCLUSIONS

Participants who self-monitor or self-manage can improve the quality of their oral anticoagulation therapy. Thromboembolic events were reduced, for both those self-monitoring or self-managing oral anticoagulation therapy. A reduction in all-cause mortality was observed in trials of self-management but not in self-monitoring, with no effects on major haemorrhage.

The clinical effectiveness and cost-effectiveness of point-of-care tests (CoaguChek system, INRatio2 PT/INR monitor and ProTime Microcoagulation system) for the self-monitoring of the coagulation status of people receiving long-term vitamin K antagonist therapy, compared with standard UK practice: systematic review and economic evaluation

BACKGROUND

Self-monitoring (self-testing and self-management) could be a valid option for oral anticoagulation therapy monitoring in the NHS, but current evidence on its clinical effectiveness or cost-effectiveness is limited.

OBJECTIVES

We investigated the clinical effectiveness and cost-effectiveness of point-of-care coagulometers for the self-monitoring of coagulation status in people receiving long-term vitamin K antagonist therapy, compared with standard clinic monitoring.

DATA SOURCES

We searched major electronic databases (e.g. MEDLINE, MEDLINE In Process & Other Non-Indexed Citations, EMBASE, Bioscience Information Service, Science Citation Index and Cochrane Central Register of Controlled Trials) from 2007 to May 2013. Reports published before 2007 were identified from the existing Cochrane review (major databases searched from inception to 2007). The economic model parameters were derived from the clinical effectiveness review, other relevant reviews, routine sources of cost data and clinical experts' advice.

REVIEW METHODS

We assessed randomised controlled trials (RCTs) evaluating self-monitoring in people with atrial fibrillation or heart valve disease requiring long-term anticoagulation therapy. CoaguChek(®) XS and S models (Roche Diagnostics, Basel, Switzerland), INRatio2(®) PT/INR monitor (Alere Inc., San Diego, CA USA), and ProTime Microcoagulation system(®) (International Technidyne Corporation, Nexus Dx, Edison, NJ, USA) coagulometers were compared with standard monitoring. Where possible, we combined data from included trials using standard inverse variance methods. Risk of bias assessment was performed using the Cochrane risk of bias tool. A de novo economic model was developed to assess the cost-effectiveness over a 10-year period.

RESULTS

We identified 26 RCTs (published in 45 papers) with a total of 8763 participants. CoaguChek was used in 85% of the trials. Primary analyses were based on data from 21 out of 26 trials. Only four trials were at low risk of bias. Major clinical events: self-monitoring was significantly better than standard monitoring in preventing thromboembolic events [relative risk (RR) 0.58, 95% confidence interval (CI) 0.40 to 0.84; p = 0.004]. In people with artificial heart valves (AHVs), self-monitoring almost halved the risk of thromboembolic events (RR 0.56, 95% CI 0.38 to 0.82; p = 0.003) and all-cause mortality (RR 0.54, 95% CI 0.32 to 0.92; p = 0.02). There was greater reduction in thromboembolic events and all-cause mortality through self-management but not through self-testing. Intermediate outcomes: self-testing, but not self-management, showed a modest but significantly higher percentage of time in therapeutic range, compared with standard care (weighted mean difference 4.44, 95% CI 1.71 to 7.18; p = 0.02). Patient-reported outcomes: improvements in patients' quality of life related to self-monitoring were observed in six out of nine trials. High preference rates were reported for self-monitoring (77% to 98% in four trials). Net health and social care costs over 10 years were £7295 (self-monitoring with INRatio2); £7324 (standard care monitoring); £7333 (self-monitoring with CoaguChek XS) and £8609 (self-monitoring with ProTime). The estimated quality-adjusted life-year (QALY) gain associated with self-monitoring was 0.03. Self-monitoring with INRatio2 or CoaguChek XS was found to have ≈ 80% chance of being cost-effective, compared with standard monitoring at a willingness-to-pay threshold of £20,000 per QALY gained.

CONCLUSIONS

Compared with standard monitoring, self-monitoring appears to be safe and effective, especially for people with AHVs. Self-monitoring, and in particular self-management, of anticoagulation status appeared cost-effective when pooled estimates of clinical effectiveness were applied. However, if self-monitoring does not result in significant reductions in thromboembolic events, it is unlikely to be cost-effective, based on a comparison of annual monitoring costs alone. Trials investigating the longer-term outcomes of self-management are needed, as well as direct comparisons of the various point-of-care coagulometers.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013004944.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Self-Management of Anticoagulant Therapy in Mechanical Heart Valve Patients: A Matched Cohort Study

BACKGROUND

Patient-self-management (PSM) of oral anticoagulant therapy with vitamin K antagonists for mechanical heart valves has demonstrated efficacy in randomized controlled trials. However, the effectiveness of PSM in clinical practice has only been investigated in small trials. Our aim was to evaluate the effectiveness of PSM of oral anticoagulant therapy in mechanical heart valve patients.

METHODS

We conducted a matched cohort study: cases were patients with a mechanical heart valve performing PSM affiliated with Aarhus University Hospital or Aalborg University Hospital, Denmark, in the period 1996 to 2012 (n = 615). Prospectively registered patient data were obtained from databases at two hospitals, and cross linkage between these databases and national patient registries provided detailed information on comorbidities and events. Control patients were matched (on sex, date of birth, year of first valve surgery, and grouped valve position) in a ratio of 5:1 (n = 3,075) with patients receiving conventional management who were randomly selected within the match group. The effectiveness and safety was estimated using major bleeding and thromboembolic events and death as outcomes.

RESULTS

We observed low event rates in the PSM group. After 5 years, PSM was associated with a lower risk of all-cause mortality compared with conventional management (adjusted hazard ratio of 0.49, 95% confidence interval: 0.34 to 0.71). The hazard ratios for thromboembolism and major bleeding were 0.91 (95% confidence interval: 0.66 to 1.24) and 0.83 (95% confidence interval: 0.56 to 1.22).

CONCLUSIONS

Owing to superior clinical effectiveness, self-managed oral anticoagulant therapy may potentially improve the standard of care for patients with mechanical heart valves.

Primary prophylaxis for venous thromboembolism in patients undergoing cardiac or thoracic surgery

BACKGROUND

Cardiac and thoracic surgery are associated with an increased risk of venous thromboembolism (VTE). The safety and efficacy of primary thromboprophylaxis in patients undergoing these types of surgery is uncertain.

OBJECTIVES

To assess the effects of primary thromboprophylaxis on the incidence of symptomatic VTE and major bleeding in patients undergoing cardiac or thoracic surgery.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 2014) and CENTRAL (2014, Issue 4). The authors searched the reference lists of relevant studies, conference proceedings, and clinical trial registries.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing any oral or parenteral anticoagulant or mechanical intervention to no intervention or placebo, or comparing two different anticoagulants.

DATA COLLECTION AND ANALYSIS

We extracted data on methodological quality, participant characteristics, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively.

MAIN RESULTS

We identified 12 RCTs and one quasi-RCT (6923 participants), six for cardiac surgery (3359 participants) and seven for thoracic surgery (3564 participants). No study evaluated fondaparinux, the new oral direct thrombin, direct factor Xa inhibitors, or caval filters. All studies had major study design flaws and most lacked a placebo or no treatment control group. We typically graded the quality of the overall body of evidence for the various outcomes and comparisons as low, due to imprecise estimates of effect and risk of bias. We could not pool data because of the different comparisons and the lack of data. In cardiac surgery, 71 symptomatic VTEs occurred in 3040 participants from four studies. In a study of 2551 participants, representing 85% of the review population in cardiac surgery, the combination of unfractionated heparin with pneumatic compression stockings was associated with a 61% reduction of symptomatic VTE compared to unfractionated heparin alone (1.5% versus 4.0%; risk ratio (RR) 0.39; 95% confidence interval (CI) 0.23 to 0.64). Major bleeding was only reported in one study, which found a higher incidence with vitamin K antagonists compared to platelet inhibitors (11.3% versus 1.6%, RR 7.06; 95% CI 1.64 to 30.40). In thoracic surgery, 15 symptomatic VTEs occurred in 2890 participants from six studies. In the largest study evaluating unfractionated heparin versus an inactive control the rates of symptomatic VTE were 0.7% versus 0%, respectively, giving a RR of 6.71 (95% CI 0.40 to 112.65). There was insufficient evidence to determine if there was a difference in the risk of major bleeding from two studies evaluating fixed-dose versus weight-adjusted low molecular weight heparin (2.7% versus 8.1%, RR 0.33; 95% CI 0.07 to 1.60) and unfractionated heparin versus low molecular weight heparin (6% and 4%, RR 1.50; 95% CI 0.26 to 8.60).

AUTHORS' CONCLUSIONS

The evidence regarding the efficacy and safety of thromboprophylaxis in cardiac and thoracic surgery is limited. Data for important outcomes such as pulmonary embolism or major bleeding were often lacking. Given the uncertainties around the benefit-to-risk balance, no conclusions can be drawn and a case-by-case risk evaluation of VTE and bleeding remains preferable.

Cohort study of Anticoagulation Self-Monitoring (CASM): a prospective study of its effectiveness in the community

BACKGROUND

Trials show that oral anticoagulation therapy (OAT) substantially reduces thromboembolic events without an increase in major haemorrhagic events, but it is not known whether these results translate into routine practice.

AIM

To estimate the current levels of control and adverse events in patients self-monitoring OAT, explore the factors that predict success, and determine whether the level of side effects reported from randomised controlled trials are translated to a non-selected population.

DESIGN AND SETTING

Prospective cohort study in the UK.

METHOD

Participants were aged ≥18 years and registered with a GP. Main outcomes were the proportion of participants, over 12 months, who were still self-monitoring, had not experienced adverse events, and had achieved >80% of time in therapeutic range (TTR).

RESULTS

In total, 296 participants were recruited; their median age was 61 years and 55.1% were male. Participants were predominately professional or held a university qualification (82.7%). At 12 months, 267 (90.2%) were still self-monitoring. Mean TTR was 75.3% (standard deviation 16.9).Six serious and two minor adverse events were reported by GPs. Only 45.9% of participants received any in-person training at the outset. Increased age (P = 0.027), general wellbeing (EQ-5D visual score, P = 0.020), and lower target international normalised range (INR, P = 0.032) were all associated with high (>80% TTR) levels of control.

CONCLUSION

The findings show that, even with little training, people on OAT can successfully self-monitor, and even self-manage, their INR. TTR was shown to improve with age. However, widespread use of self-monitoring of INR may be limited by the initial costs, as well as a lack of training and support at the outset.

Security and cost comparison of INR self-testing and conventional hospital INR testing in patients with mechanical heart valve replacement

Background

International normalized ratio (INR) self-testing can improve the management of anticoagulation therapy with warfarin for the patients following mechanical heart valve replacement. Several reviews and studies have demonstrated self-management as an option to improve patient’s outcome considerably after mechanical heart valve replacement. We sought to analyze the security, economy and discuss the prospect of self-testing of anticoagulation therapy in patients following mechanical heart valve replacement in China, and evaluate the accuracy and stability of CoaguChek XS portable INR-testing device.

Methods

This was a prospective self-controlled clinical study conducted with 526 patients receiving oral warfarin anticoagulation therapy after mechanical heart valve replacement in the period of Mar.1, 2012 – Nov.1, 2012 in Cardiovascular Surgery Department of West China Hospital of Sichuan University. The same patient performed INR testing with CoaguChek XS portable coagulometer (group1) and central lab (group 2) in parallel. The follow-up time was 6 months. Meanwhile, a questionnaire was handed out to survey the expenses required for the re-examination visits to the hospital, time, and anticoagulation complications.

Results

No severe anticoagulation complications occurred in all the patients. No significant difference of the INR results were observed between group 1 and group 2, they showed significant relevance, r = 0.953(p < 0.05). Compared with the conventional method of INR testing in hospital, the portable coagulometer is convenient, quick and less traumatic. Self-testing of anticoagulation therapy reduced the cost and the time required for re-examination.

Conclusions

Results of CoaguChek XS monitor are precise and have a good consistency and stability as compared with traditional laboratory testing. For the patients receiving anticoagulation therapy after mechanical heart valve replacement, the self-testing of anticoagulation therapy with portable coagulometer is a safe choice, and it has a promising future application in China.

Economic evaluation of the use of point-of-care devices in patients with long term oral anticoagulation

To examine the cost and cost-effectiveness of the use of point-of-care (POC) devices by the general practitioner (GP), in anticoagulation clinic or by the patient in self-testing (PST) and self-management (PSM), compared with standard laboratory testing to realize international normalized ratio tests for patients on long term anticoagulation therapy. An economic evaluation was performed from the Belgian health care payer's perspective using a Markov model. Outcomes data were derived from a meta-analysis and cost data were derived from claims databases. Several scenarios were tested based on number of tests and GP's contacts and probabilistic sensitivity analysis was used to handle uncertainty. Evidence on the impact of POC on mortality was only found for PSM. Therefore, a cost-effectiveness analysis was performed for PSM and for other strategies, only a cost comparison was done. With an unchanged number of tests, POC is cost-saving compared to laboratory testing (probability > 70%). In scenarios where POC induces more tests, results were different: with 52 tests/year, only PSM kept a probability of remaining cost-saving superior to 50%. Except in the case of 100% of GP consultations maintained and 52 tests/year performed, PSM resulted in significantly more "life years gained" (LYG) than usual care and was on average cost-saving. The organisation of long term oral anticoagulation monitoring should be directed towards PSM and, to a lesser extent, PST for selected and trained patients.

Anticoagulation early after mechanical valve replacement: improved management with patient self-testing

OBJECTIVE

Self-testing to determine the international normalized ratio improves management with warfarin and reduces the risks of adverse events. Self-testing usually begins several weeks after hospital dismissal after valve replacement. We aimed to compare the in-hospital initiation of international normalized ratio self-testing with usual care in mechanical heart valve recipients.

METHODS

A total of 200 adult mechanical heart valve recipients were randomly assigned to in-hospital international normalized ratio self-testing instruction or usual care. Instruction for self-testing patients began on the fourth postoperative day. The patients were followed up for 3 months to compare the number of international normalized ratio tests, percentage of time in the therapeutic range, and adverse events.

RESULTS

The baseline characteristics were similar between the 2 groups. During the first 3 postoperative months, the usual-care group underwent an average of 10 international normalized ratio tests, and the self-testing group completed 14 international normalized ratio tests. The mean ± SD percentage of international normalized ratio tests within the therapeutic range was 45% ± 22% for the usual-care group and 52% ± 22% for the self-testing group (P = .05). Within 90 days after dismissal, transient ischemic attack occurred in 1 patient in the usual-care group and 2 patients in the self-testing group. Bleeding complications occurred in 3 patients in the usual-care group and 5 patients in the self-testing group.

CONCLUSIONS

Management of anticoagulation with warfarin after mechanical valve replacement is improved with self-testing, even during the early postoperative phase when international normalized ratio testing is performed frequently. Although the incidence of adverse events was similar in the 2 groups, better control of the international normalized ratio would be expected to improve outcome in large populations of patients.

Anticoagulation patient self-monitoring in the United States: considerations for clinical practice adoption

Systematic management models such as anticoagulation clinics have emerged in order to optimize warfarin effectiveness and to minimize related complications. Most of these models are structured so that patients come to a clinic for in-person testing and evaluation, thus making this model of care difficult to access and time consuming for many patients. The emergence of portable instruments for measuring anticoagulant effect in capillary whole blood made it possible for patients receiving warfarin to self-monitor the effect of their anticoagulant therapy. Self-monitoring empowers patients, offers the advantage of more frequent monitoring, and increases patient convenience by allowing testing at home and avoiding the need for frequent laboratory and clinic visits. Self-monitoring can entail patient self-testing (PST) and/or patient self-management (PSM). Several studies have evaluated and shown the benefit of both PST and PSM models of care when compared with either routine medical care or anticoagulation clinic management of anticoagulation therapy. Self-monitoring (PSM and/or PST) of anticoagulation results in lower thromboembolic events, lower mortality, and no increase in major bleeding when compared with standard care. Despite favorable results and enhanced patient convenience, the adoption of self-monitoring into clinical practice in the United States has been limited, especially in higher risk, disadvantaged populations. Although the emergence of a multitude of novel oral anticoagulants will permit clinicians to better individualize anticoagulant therapy options by choosing the optimum regimen based on individual patient characteristics, it is also expected that traditional agents will continue to play a role in a significant subset of patients. For those patients treated with traditional anticoagulants such as warfarin, future models of care will entail patient-centered management such as PST and PSM. The incorporation of technology (i.e., Web-based expert systems) is expected to further improve the outcomes realized by PST and PSM. Further studies are needed to explore factors that influence the adoption of self-monitoring in the United States and to evaluate the feasibility and implementation in real-life clinical settings.

Long-term self-management of anticoagulation therapy after mechanical heart valve replacement in outside trial conditions

In this investigation, we hypothesize that quality of oral anticoagulation (OA) and long-term outcome after mechanical heart valve (MHV) replacement with self-management (Self-M) of OA is superior to conventional anticoagulation treatment (Conv-T), even in outside trial conditions. One hundred sixty patients (78.8% aortic valve replacements) were trained in international normalized ratio Self-M and 260 patients (86.2% aortic valve replacements) preferred Conv-T. Mean follow-up was 8.6 ± 2.1 years, representing 3612 patient-years. During follow-up, 37.2% bleedings and 10.6% thromboembolic events were recorded in the Self-M group versus 39.6% bleedings (P = 0.213) and 15.4% thromboembolic events (P = 0.064) in the Conv-T group. Serious adverse events were significantly lower in the Self-M group [grade III bleeding events causing disability or death: 0 versus 4.6% (P = 0.03); grade III thromboembolic events: 0.6 versus 5.0% (P = 0.011)]. Patients with Self-M were significantly more satisfied with their OA management and their quality of life (P < 0.001). Actuarial survival after 1, 5 and 10 years was 100, 99 and 97 with Self-M and 100, 95 and 81% with Conv-T, respectively (P < 0.001). Univariate risk factors for mortality were age (P = 0.008), type of operation (P = 0.021) and conventional OA (P < 0.001). In multivariate analysis, only conventional OA reached significance (P < 0.001). We conclude that in a routine setting under outside trial conditions Self-M of OA improves long-term outcome and treatment quality.

The Bentall procedure: is it the gold standard? A series of 597 consecutive cases

OBJECTIVES

We compared aortic root reconstructions using conduits with biological valves and mechanical valves.

METHODS

Of 597 patients (1995-2008), 307 (mean age 71 years [23-89 years]) had biological valves and 290 (mean age 51 years [21-82 years]) had mechanical valves. The subgroup of 242 patients aged 50 to 70 years included 133 with biological and 109 with mechanical valves.

RESULTS

Overall hospital mortality was 3.9% with biological valves (n = 15; elective: 3.7% [n = 10]) versus 2.8% with mechanical valves (n = 8; elective: 1.4% [n = 3]). In patients 50 to 70 years, age greater than 65 years (relative risk: 3.3 [P = .0001]), clot (relative risk: 2.5 [P = .05]), coronary artery disease (relative risk:3.5 [P < .0001]), and degenerative etiology (relative risk: 0.4 [P = .006]) were independent risk factors for long-term survival (after postoperative day 30); there was no difference in long-term survival between biological and mechanical valves (relative risk: 0.9 [P = .74]). The linearized rate for valve/ascending aorta reoperation was 0.86%/pt-y (2 in 2310 pt-y) after mechanical valves and 2.5%/pt-y (4 in 1586 pt-y) after Bentall procedures with the biological valve.

CONCLUSIONS

The choice of valve for aortic root reconstruction seems to have no influence on long-term outcome. Emergency operation and the presence of clot/atheroma have a significant impact on short-term outcome. Reoperation for either ascending aorta and/or aortic valve is low.

Knowledge of Patients with Mechanical Valve Prostheses Concerning Chronic Oral Anticoagulant Therapy

Adherence to chronic Oral Anticoagulant Therapy (OAT) is directly related to patients' understanding of the therapy. This study verified the knowledge of patients with mechanical valve prostheses concerning OAT. This is a contemporary cross-sectional study, the sample is composed of patients with mechanical valve prostheses (MVP) in outpatient follow-up. A 10-question instrument was used; answers were ‘know' (1 point), ‘know partially' (half point), or ‘do not know' (zero). Patients were grouped according to the result obtained: ≤ 4 points was considered insufficient knowledge; > 4 ≤ 8 equated to moderate knowledge; and > 8 was considered appropriate knowledge. Of the 110 patients, 61.8% presented moderate knowledge, 40.9% were not able to name at least one factor that may alter the INR (International Normalized Ratio) and 37.3% were not able to report their INR target range. The majority of patients presented moderate knowledge concerning the treatment. Strategies to improve knowledge on the topic should be implemented to minimize risks.

Acoustical analysis of mechanical heart valve sounds for early detection of malfunction

Mechanical heart valves carry the disadvantage of lifelong antithrombotic therapy, due to the high risk of thrombus formation on the valve surface. Current diagnostic methods are incapable of detecting thrombus formation in an early stage. This article investigates a new diagnostic method, based on the analysis of the acoustic signal produced by the valve. This method should be capable of early detection of malfunction, thus permitting targeted medication and reducing valve-related complications and mortality. A measurement setup assuring optimal signal quality was developed, and a signal analysis program was implemented and validated on an in vitro mock circulatory loop. Next, four sheep were implanted with a bileaflet mechanical valve. The signals of their valves developing thrombosis were assessed on a weekly basis before explantation. Three sheep were sacrificed shortly after detection of malfunction according to the newly developed method. In each case, thrombus or membrane formation was detected on the leaflets upon explantation. In one sheep, no malfunction was found in the analysis, which was also confirmed by the condition of the valve upon explantation. These preliminary results indicate that acoustical analysis of mechanical heart valves permits early detection of valvular malfunction. Further research with more in vitro and animal testing is required to statistically validate these findings.

International normalized ratio self-management lowers the risk of thromboembolic events after prosthetic heart valve replacement

BACKGROUND

Although prosthetic valves are durable and easy to implant, the need for lifetime warfarin-based anticoagulation restricts their exclusive usage. We investigated if anticoagulation self-management improves outcome in a single-center series.

METHODS

Between 1994 and 1998, 765 patients with prosthetic valve replacements were prospectively enrolled and randomized to receive conventional anticoagulation management by their primary physician (group 1, n = 295) or to pursue anticoagulation self-management (group 2, n = 470). A study head office was implemented to coordinate and monitor anticoagulation protocols, international normalized ratios (INR), and adverse events. Patients were instructed on how to obtain and test their own blood samples and to adjust warfarin dosages according to the measured INR (target range, 2.5 to 4).

RESULTS

Mean INR values were slightly yet significantly smaller in group 1 than in group 2 (2.8 +/- 0.7 vs 3.0 +/- .6, p < 0.001). Moreover, INR values of patients with conventional INR management were frequently measured outside the INR target range, whereas those with anticoagulation self-management mostly remained within the range (35% vs 21%, p < 0.001). In addition, the scatter of INR values was smaller if self-managed. Freedom from thromboembolism at 3, 12, and 24 months, respectively, was 99%, 95%, and 91% in group 1 compared with 99%, 98%, and 96% in group 2 (p = 0.008). Bleeding events were similar in both groups. Time-related multivariate analysis identified INR self-management and higher INR as independent predictors for better outcome.

CONCLUSIONS

Anticoagulation self-management can improve INR profiles up to 2 years after prosthetic valve replacement and reduce adverse events. Current indications of prosthetic rather than biologic valve implantations may be extended if the benefit of INR self-management is shown by future studies with longer follow-up.

Aortic Valve Replacement With 17-mm St. Jude Medical Prostheses for a Small Aortic Root in Elderly Patients

BACKGROUND

There are few reports about the optimal prosthesis for elderly patients who have small aortic roots with an aortic annular size of less than 19 mm.

METHODS

From October 2004 to October 2006, 11 women aged 70 years or older (mean age, 74.9 +/- 3.5 years) underwent aortic valve replacement with a 17-mm Regent prosthesis (St. Jude Medical, St. Paul, MN), with the size determined using the manufacturer's sizer. Clinical status and the results of preoperative and postoperative echocardiography were evaluated.

RESULTS

The patients had a mean body surface area of 1.33 +/- 0.13 m2. Preoperative average New York Heart Association (NYHA) functional class was 2.5 +/- 0.7. Preoperative echocardiography showed a mean indexed effective orifice area of 0.33 +/- 0.14 cm2/m2 and a left ventricular mass index of 175 +/- 63 g/m2. Seven patients underwent associated procedures. Postoperative ventilation time was 14 +/- 5.6 hours, and the intensive care unit stay was 1.0 +/- 0.4 days. No patients died perioperatively. The NYHA functional class improved to class I in 9 patients. No obstruction of valve opening was observed. A significant increase in the mean indexed effective orifice area (0.87 +/- 0.10 cm2/m2) and regression of left ventricular mass index were found (114 +/- 46 cm2/m2) on postoperative echocardiography.

CONCLUSIONS

Aortic valve replacement in elderly patients with small aortic roots (less than 19 mm) using a 17-mm Regent prosthesis showed satisfactory clinical and hemodynamic results.