INR self-management permits lower anticoagulation levels after mechanical heart valve replacement

Combining portable coagulometers with the Internet: A new model of warfarin anticoagulation in patients following mechanical heart valve replacement

Heart valve replacement, as a safe and effective treatment for severe valvular heart disease, can significantly improve hemodynamics in patients. However, such patients then require lifelong anticoagulant therapy. Warfarin, a cheap and highly effective vitamin K antagonist, remains the major anticoagulant recommended for lifelong use following mechanical heart valve replacement. However, the effect of warfarin anticoagulant therapy is complicated by physiological differences among patients and non-compliance with treatment at different degrees. Effective management of warfarin therapy after heart valve replacement is currently an important issue. Portable coagulometers and the emergence of the Internet have provided new opportunities for long-term management of anticoagulation therapy, but the safety and affordability of this approach remain to be fully evaluated. This paper reviews recent progress on the use of portable coagulometers and the Internet in the management of warfarin anticoagulation therapy following mechanical heart valve replacement, which offers opportunities for reducing complications during postoperative anticoagulation and for facilitating patient compliance during follow-up.

Perioperative and long-term outcomes of Ross versus mechanical aortic valve replacement

Background

The ideal aortic valve replacement strategy in young‐ and middle‐aged adults remains up for debate. Clinical practice guidelines recommend mechanical prostheses for most patients less than 50 years of age undergoing aortic valve replacement. However, risks of major hemorrhage and thromboembolism associated with long‐term anticoagulation may make the pulmonary autograft technique, or Ross procedure, a preferred approach in select patients.

Methods

Data were retrospectively collected for patients 18–50 years of age who underwent either the Ross procedure or mechanical aortic valve replacement (mAVR) between January 2000 and December 2016 at a single institution. Propensity score matching was performed and yielded 32 well‐matched pairs from a total of 216 eligible patients.

Results

Demographic and preoperative characteristics were similar between the two groups. Median follow‐up was 7.3 and 6.9 years for Ross and mAVR, respectively. There were no early mortalities in either group and no statistically significant differences were observed with respect to perioperative outcomes or complications. Major hemorrhage and stroke events were significantly more frequent in the mAVR population (p < .01). Overall survival (p = .93), freedom from reintervention and valve dysfunction free survival (p = .91) were equivalent.

Conclusions

In this mid‐term propensity score‐matched analysis, the Ross procedure offers similar perioperative outcomes, freedom from reintervention or valve dysfunction as well as overall survival compared to traditional mAVR but without the morbidity associated with long‐term anticoagulation. At specialized centers with sufficient expertize, the Ross procedure should be strongly considered in select patients requiring aortic valve replacement.

Efficacy and safety of low intensity vitamin K antagonists in Western and East-Asian patients with left-sided mechanical heart valves

The optimal INR target in patients with mechanical heart valves is unclear. Higher INR targets are often used in Western compared with East Asian countries. The objective of this systematic review and meta-analysis was to summarize the evidence for the efficacy and safety of lower versus higher INR targets in Western and East Asian left-sided mechanical heart valve patients. We searched Western databases including Cochrane CENTRAL, Medline, and Embase as well as Chinese databases including SinoMed, CNKI, and Wanfang Data in addition to grey literature for Randomized Controlled Trials (RCTs) and observational studies. We pooled risk ratios (RRs) using random-effects model. Low and high INR targets were defined by the individual studies. We identified nine RCTs, including six Western (n = 5496) and three East Asian (n = 209) trials, and 17 observational studies, including two Western (n = 3199) and 15 East Asian (n = 5485) studies. In the RCTs, lower compared with higher targets were associated with similar rates of thromboembolism (2.4 vs. 2.3%; RR: 1.14, 95% CI 0.82, 1.60, I² = 0%) and lower rates of both total bleeding (21.9 vs. 40.9%, RR: 0.46, 95% CI 0.28, 0.78, I² = 88%) and major bleeding. RCT data showed no statistical heterogeneity by region. These effects were consistent in the observational data. We downgraded the quality of evidence due to serious risk of bias and imprecision. In patients with left-sided contemporary mechanical heart valves, low quality evidence suggests lower INR targets are associated with similar rates of thromboembolism and moderate quality evidence suggests lower rates of bleeding.

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.

Outcomes related to anticoagulation management for mechanical valve replacements

Background

This study evaluates anticoagulation management and its impact on longitudinal clinical outcomes in patients undergoing mechanical valve replacement.

Methods

Patients undergoing mechanical mitral valve replacement (MVR) or aortic valve replacement (AVR) from 2010–2018 at a single center were included. Patients were stratified into therapeutic and non-therapeutic anticoagulation groups based on the median percentage of international normalized ratio (INR) values within the reference range (2.0–3.0 for AVR, 2.5–3.5 for MVR) during the first post-operative year. Using Cox regression analysis, comorbidity-adjusted survival and freedom from adverse events were compared.

Results

Six hundred and fifty-one patients underwent mechanical valve replacement (166 MVR, 485 AVR). Comorbidity-adjusted survival was similar in the MVR and AVR cohorts (P=0.23). There was a median of 27 [interquartile range (IQR): 14–42] INRs drawn per patient in the first post-operative year. The median percentage of INRs within the reference values during the first post-operative year was 42.85% (IQR: 30.77–53.95%), with the majority of non-therapeutic INRs being subtherapeutic (34.51%; n=6,864). There were no significant differences in adjusted survival between the therapeutic and non-therapeutic groups [hazard ratio (HR): 1.12, P=0.73]. Within the first post-operative year, there were no significant differences in stroke, major bleeding, peripheral non-stroke arterial thromboembolism, and readmission for intravenous heparin in the therapeutic and non-therapeutic groups.

Conclusions

Taking into account relevant comorbidities and valve type, patients with a larger proportion of non-therapeutic INRs during the first post-operative year demonstrated no difference in longitudinal clinical outcomes. Further research into more standardized INR monitoring and potentially expanded INR target ranges for patients undergoing mechanical valve replacement is warranted.

Predictors of Use and Outcomes of Mechanical Valve Replacement in the United States (2008-2017)

Background

Contemporary nationwide data on the use, predictors, and outcomes of mechanical valve replacement in patients less than 70 years of age are limited.

Methods and Results

We identified hospitalizations for aortic valve replacement (AVR) or mitral valve replacement (MVR) in the Nationwide Inpatient Sample between January 1, 2008, and December 31, 2017. The study's end points included predictors of mechanical valve replacement and risk‐adjusted in‐hospital mortality. Among 253 100 hospitalizations for AVR, the use rate of mechanical prosthesis decreased from 45.3% in 2008 to 17.0% in 2017. Among 284 962 hospitalizations for MVR, mechanical prosthesis use decreased from 59.5% in 2008 to 29.2% in 2017 (P for trend<0.001). In multilogistic regression analyses, female sex, prior sternotomy, prior defibrillator, and South/West geographic location were predictive of mechanical valve use. The presence of bicuspid valve was a negative predictor of mechanical AVR (odds ratio [OR], 0.68; 95% CI, 0.66–0.69; P<0.001), whereas mitral stenosis was associated with higher mechanical MVR (OR, 1.28; 95% CI, 1.22–1.33; P<0.001). Unadjusted in‐hospital mortality decreased over time with AVR but not with MVR, regardless of prosthesis choice. Using years 2008 and 2009 as a reference, risk‐adjusted mortality also decreased over time with AVR but did not decrease after MVR.

Conclusions

There is a substantial decline in the use of mechanical valve replacement among patients aged ≤70 years in the United States. Long‐term durability data on bioprosthetic valve replacement are needed to better define the future role of mechanical valves in this age group.

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.

Long-term effectiveness and safety of self-management of oral anticoagulants in real-world settings

Background

The patient self-management (PSM) is an effective approach for controlling the international normalized ratio, INR, within the therapeutic range. Nevertheless, most of the literature derives from randomized clinical trials, and no from routine clinical practice. The main objective of the present study was to evaluate long-term effectiveness and safety of PSM of oral anticoagulants (OACs) in real-world settings.

Methods

This prospective cohort study involved 808 patients who were trained for PSM between July 2009 and March 2012, and followed-up for a maximum observational period of 5 years. The follow-up consisted of a visit to the physician every 6 months. All patients used the same type of portable coagulometer, able to store digitally up to 100 INR measurements. Effectiveness outcomes included the percentage of patients within the therapeutic range, the time within therapeutic range (TTR), and the evolution of the TTR over 365 days of follow-up. Long-term safety profile of PSM included the incidence of all-cause deaths and complications (thromboembolic or hemorrhagic) reported between July 2009 and June 2014, and the time to event.

Results

The median follow-up was 3.3 years. The percentage of patients within therapeutic INR target range was 67.5%. The median TTR was 71.5%. The TTR increased over the follow-up period, either overall and regarding target INR. All-cause mortality was 2.4 per 100 patient-years (59 cases). The thromboembolic event rate was 0.9 per 100 patient-years (24 cases). The rate of major hemorrhages was 0.45 per 100 patient-years. Patients who drop out the PSM to perform the conventional management had greater rates of complications: 2.4, 1.8, and 3.4 per 100 patient-years for thromboembolic complications, major hemorrhagic events, and mortality, respectively.

Conclusions

The PSM of OACs is effective for maintaining patients within the INR therapeutic range for a long period of time in routine clinical practice. Results of the present study suggest that its effectiveness is at least comparable to the conventional management. Moreover, it seems safe in real-world settings, by preventing all-cause mortality, and thromboembolic and major hemorrhagic complications.

Trial registration

This study was not a trial, thus registration was not required.

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.

Low-dose anticoagulation after isolated mechanical aortic valve replacement with Liva Nova Bicarbon prosthesis: A post hoc analysis of LOWERING-IT Trial

Thromboembolic complications after cardiac valve replacement are due to a complex interplay between patients' characteristics, device features and anticoagulation intensity. Subtle design and material differences in available prostheses may thrombosis. We conducted a post-hoc sub-analysis of the LOWERING-IT database to test the safety and feasibility of a low-level oral anticoagulant regime in low-risk patients with aortic LivaNova prosthetic valve replacement. The study population included 148 patients randomized to a low INR target (1.5-2.5; LOW-INR group), and 144 patients to the standard INR (2.0-3.0; CONVENTIONAL-INR group). The non-inferiority of thromboembolic events between LOW-INR and CONVENTIONAL-INR groups was tested. Cumulative follow-up reached 1,545 patient/years. The mean INR was 1.91 ± 0.23 in the LOW-INR group, and 2.59 ± 0.26 in the CONVENTIONAL-INR group (P < 0.001). There were 3 thromboembolic events, all in the CONVENTIONAL-INR group. Comparison of thromboembolic events was not significant. The 1-sided 97.5% exact CI for the difference in primary event proportion was 0.54%, satisfying criteria non-inferiority. Bleeding events were significantly different: 6.61 per 1,000 patient-year in LOW-INR group vs 18.65 per 1,000 patient-year in CONVENTIONAL-INR group (p < 0.045, RR 0.37). In conclusions these data suggest that low-dose anticoagulation is safe in selected patients after aortic LivaNova Bicarbon prosthesis implantation.

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.

Late Mortality and Morbidity in Elderly Patients with Mechanical Heart Valves

A retrospective study was performed in patients under and over 65 years old implanted with a mechanical valve, to compare late mortality and morbidity. Of 381 patients who underwent mechanical valve replacement at Nagoya University in the 1990s, 357 (11 hospital deaths and 13 lost to follow-up; 96.4% follow-up rate) were followed up for 7.9 ± 3.3 years (2,811 patient-years). They were divided into two groups either side of 65 years of age at operation. The young and elderly patient groups contained 275 and 82 patients, respectively. The survival rate in the young group was 96.1% (95% confidence interval, 93.7%–98.5%) at 5 years and 92.0% (95% confidence interval, 88.3%–95.7%) at 10 years, which was significantly better than 88.0% (95% confidence interval, 80.6%–95.4%) at 5 years and 73.8% (95% confidence interval, 66.2%–85.4%) at 10 years in the elderly group. The two groups did not differ significantly in the incidence of thromboembolic events, bleeding events, endocarditis, or reoperation. We are also encouraged by the fact that mechanical valves are not a risk factor for late mortality or morbidity, even in elderly patients.

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.

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.

Achieved anticoagulation vs prosthesis selection for mitral mechanical valve replacement: a population-based outcome study

BACKGROUND

Thromboembolic events (TEs) are frequent after mechanical mitral valve replacement (MVR), but their association to anticoagulation quality is unclear and has never been studied in a population-based setting with patients who have a complete anticoagulation record.

METHODS

We compiled a complete record of all residents of Olmsted County, MN, who underwent mechanical MVR between 1981 and 2004, for all TE, bleeding episodes, and international normalized ratios (INRs) measured from prosthesis implantation.

RESULTS

In the 112 residents (mean [+/- SD] age, 57 +/- 16 years; 60% female residents) who underwent mechanical MVR, 19,647 INR samples were obtained. While INR averaged 3.02 +/- 0.57, almost 40% of INRs were < 2 or > 4.5. Thirty-four TEs and 28 bleeding episodes occurred during a mean duration of 8.2 +/- 6.1 years of follow-up. There was no trend of association of INR (average, SD, growth variance rate, or intensity-specific incidence of events) with TE. Previous cardiac surgery (p = 0.014) and ball prosthesis (hazard ratio [HR], 2.92; 95% CI, 1.43 to 5.94; p = 0.003) independently determined TE. With MVR using a ball prosthesis, despite higher anticoagulation intensity (p = 0.002), the 8-year rate of freedom from TE was considerably lower (50 +/- 9% vs 81 +/- 5%, respectively; p < 0.0001). Compared with expected stroke rates in the population, stroke risk was elevated with non-ball prosthesis MVR (HR 2.6; 95% CI, 1.3 to 5.2; p = 0.007) but was considerable with ball prosthesis MVR (HR 11.7; 95% CI, 7.5 to 18.4; p < 0.0001). INR variability (SD) was higher with a higher mean INR value (p < 0.0001). INR variability (HR 2.485; 95% CI, 1.11 to 5.55; p = 0.027) and cancer history (p < 0.0001) independently determined bleeding rates.

CONCLUSION

This population-based comprehensive study of anticoagulation and TE post-MVR shows that, in these closely anticoagulated patients, anticoagulation intensity was highly variable and not associated with TE incidence post-MVR. Higher anticoagulation intensity is linked to higher variability and, thus, to bleeding. The MVR-ball prosthesis design is associated with higher TE rates notwithstanding higher anticoagulation intensity, and its use should be retired worldwide.

Heart valve surgery today: indications, operative technique, and selected aspects of postoperative care in acquired valvular heart disease

BACKGROUND

Surgery plays a central role in the management of acquired valvular heart disease. The optimal diagnostic evaluation, surgical treatment, and postoperative care of these patients are only possible through a cooperative effort of the primary care physician, the cardiologist, and the cardiac surgeon.

METHODS

The literature was selectively searched for information on surgical indications, operative techniques, and postoperative care in acquired valvular heart disease. Evidence-based guidelines and treatment recommendations were also taken into account.

RESULTS

A wide variety of techniques and implants are now available for the surgical treatment of acquired valvular heart disease. If they are used in evidence-based fashion, the perioperative mortality is low and the long-term outcome is favorable.

CONCLUSIONS

The volume of surgery for acquired valvular heart disease in Germany has increased substantially in recent years, from 25,495 cases in 2002 (corresponding to 26.5% of all heart operations in that year) to 33,412 in 2007 (36.5% of all heart operations). The causes for this include both demographic changes and the availability of new, less invasive surgical techniques that yield better results in elderly and/or multimorbid patients. Because of these new techniques, the indications for surgery have widened, while the results have remained favorable.

Safety and effectiveness of point-of-care monitoring devices in patients on oral anticoagulant therapy: a meta-analysis

BACKGROUND

Point-of-care devices (POCDs) for monitoring long-term oral anticoagulation therapy (OAT) may be a useful alternative to laboratory-based international normalized ratio [INR] testing and clinical management.

PURPOSE

To determine clinical outcomes of the use of POCDs for OAT management by performing a meta-analysis. Previous meta-analyses on POCDs have serious limitations.

DATA SOURCES

PubMed, the Cochrane Library, DIALOG, MEDLINE, EMBASE, BIOSIS Previews and PASCAL databases.

STUDY SELECTION

Randomized controlled trials of patients on long-term OAT, comparing anticoagulation monitoring by POCD with laboratory INR testing and clinical management.

DATA EXTRACTION

1) rates of major hemorrhage; 2) rates of major thromboembolic events; 3) percentage of time that the patient is maintained within the therapeutic range; 4) deaths. Outcomes were compared using a random-effects model. Summary measures of rates were determined. The quality of studies was assessed using the Jadad scale.

DATA SYNTHESIS

Seventeen articles (16 studies) were included. Data analysis showed that POCD INR testing reduced the risk of major thromboembolic events (odds ratio [OR] = 0.51; 95% confidence interval [CI] 0.35-0.74), was associated with fewer deaths (OR = 0.58; 95% CI = 0.38-0.89), and resulted in better INR control compared with laboratory INR testing. No significant difference between the two management modalities with respect to odds ratios for major hemorrhage was found.

LIMITATIONS

Quality scores varied from 1 to 3 (out of a maximum of 5). Only 3 studies defined how thromboembolic events would be diagnosed, casting doubt on the accuracy of the reporting of thromboembolic events. The studies suggest that only 24% of patients are good candidates for self-testing and self-management. Compared with patients managed with laboratory-based monitoring, POCD patients underwent INR testing at a much higher frequency and received much more intensive education on OAT management.

CONCLUSIONS

The use of POCDs is safe and may be more effective than laboratory-based monitoring. However, most patients are not good candidates for self-testing and self-management. Patient education and frequency of testing may be the most important factors in successful PODC management. Definitive conclusions about the clinical benefits provided by self-testing and self-management require more rigorously designed trials.

Fixed dosage of low-molecular-weight heparins causes large individual variation in coagulability, only partly correlated to body weight

BACKGROUND

Low-molecular-weight heparins (LMWHs) are routinely given without the control of their effect on coagulation. The endogenous thrombin potential (ETP) is a sensitive detector of the heparin effect.

QUESTION

What is the interindividual variation in TG after a fixed dose of LMWH in normal volunteers, is it explained by variation in weight?

METHODS

Subcutaneous (s.c.) injection, in 12 healthy volunteers, of 9000 aXa-units of unfractionated heparin (UFH) and of three heparins with narrow MW distribution around 10.5, 6.0 and 4.5 kD. Measurement of anti-thrombin (aIIa) and antifactor Xa (aXa)-activities and ETP at 11 time points over 24 h.

RESULTS

The coefficient of variation (CV) of the AUCs of aXa- and aIIa-activities is 50% for UFH and 22-37% for LMWHs. Because of the hyperbolic form of the dose-response curve, the CV of the inhibition of the ETP is lower: 32% for UFH and 13-21% for the LMWHs. Fixed dosage of LMWH caused under-dosage in 10-13% of the samples and over-dosage in 5-11%. High or low response is an individual property independent of the type of heparin injected and only partially explained by variation in body weight.

CONCLUSION

Optimized individual dosage of LMWH is possible through recognition of high and low responders, which requires one measurement of the heparin concentration or, preferably, the heparin effect on the ETP, 2-5 h after a first injection.

Anticoagulation for non-valvular atrial aibrillation - towards a new beginning with ximelagatran

OBJECTIVES: Ximelagatran is a novel oral direct thrombin inhibitor. It has favorable pharmacodynamic properties, with a broad therapeutic range without the need for anticoagulation monitoring. We aimed to discover whether ximelagatran offers a genuine future replacement to warfarin for patients in persistent atrial fibrillation (AF). MATERIALS AND METHODS: We provide an evidence-based review of the relative merits and disadvantages of warfarin and aspirin. We subsequently present an overview of the evidence for the utility of ximelagatran in the treatment of AF. RESULTS: Adjusted dose warfarin is recommended over aspirin for patients in AF at high risk of future stroke. Some of this benefit is partially offset by the higher bleeding risks associated with warfarin therapy. The SPORTIF III and V studies have shown that ximelagatran is not inferior to warfarin in the prevention of all strokes in patients with AF (both persistent and paroxysmal). This benefit was partially offset by the finding of a significant elevation of liver transaminases (>3 x normal) in 6% of patients. CONCLUSIONS: Current data would suggest that ximelagatran might represent a future alternative to warfarin. The lack of need for anticoagulant monitoring has been partially offset by a need for regular monitoring of liver function. Further data from randomized clinical trials is clearly needed.