Mechanical valve replacement for patients with rheumatic heart disease: the reality of INR control in Africa and beyond

The majority of patients requiring heart valve replacement in low- to middle-income countries (LMICs) need it for rheumatic heart disease (RHD). While the young age of such patients largely prescribes replacement with mechanical prostheses, reliable anticoagulation management is often unattainable under the prevailing socioeconomic circumstances. Cases of patients with clotted valves presenting for emergency surgery as a consequence of poor adherence to anticoagulation control are frequent. The operative mortality rates of reoperations for thrombosed mechanical valves are several times higher than those for tissue valves, and long-term results are also disappointing. Under-anticoagulation prevails in these regions that has clearly been linked to poor international normalised ratio (INR) monitoring. In industrialised countries, safe anticoagulation is defined as >60%-70% of the time in the therapeutic range (TTR). In LMICs, the TTR has been found to be in the range of twenty to forty percent. In this study, we analysed >20,000 INR test results of 552 consecutive patients receiving a mechanical valve for RHD. Only 27% of these test results were in the therapeutic range, with the vast majority (61%) being sub-therapeutic. Interestingly, the post-operative frequency of INR tests of one every 3-4 weeks in year 1 had dropped to less than 1 per year by year 7. LMICs need to use clinical judgement and assess the probability of insufficient INR monitoring prior to uncritically applying Western guidelines predominantly based on chronological age. The process of identification of high-risk subgroups in terms of non-adherence to anticoagulation control should take into account both the adherence history of >50% of patients with RHD who were in chronic atrial fibrillation prior to surgery as well as geographic and socioeconomic circumstances.

Economic evaluation in cardiac electrophysiology: Determining the value of emerging technologies

Cardiac electrophysiology is a constantly evolving speciality that has benefited from technological innovation and refinements over the past several decades. Despite the potential of these technologies to reshape patient care, their upfront costs pose a challenge to health policymakers who are responsible for the assessment of the novel technology in the context of increasingly limited resources. In this context, it is critical for new therapies or technologies to demonstrate that the measured improvement in patients' outcomes for the cost of achieving that improvement is within conventional benchmarks for acceptable health care value. The field of Health Economics, specifically economic evaluation methods, facilitates this assessment of value in health care. In this review, we provide an overview of the basic principles of economic evaluation and provide historical applications within the field of cardiac electrophysiology. Specifically, the cost-effectiveness of catheter ablation for both atrial fibrillation (AF) and ventricular tachycardia, novel oral anticoagulants for stroke prevention in AF, left atrial appendage occlusion devices, implantable cardioverter defibrillators, and cardiac resynchronization therapy will be reviewed.

SOFA Score as a Reliable Tool to Detect High Risk for Venous Thrombosis in Patients With Critical Stage SARS-CoV-2

Background: Severe acute respiratory syndrome from coronavirus-2 (SARS-CoV-2) has been associated with an increased risk of venous thromboembolism (VTE). Different anticoagulation protocols have been applied in several studies in the absence of clear evidence. A reliable deep venous thrombosis (DVT) indicator in critical patients with SARS-CoV-2 could guide the anticoagulation treatment; however, it has not yet been identified, and clinical applicability of the most common markers is debatable. The aim of our study was to determine the actual incidence of DVT in critically ill SARS-CoV-2 patients and to find a reliable tool to identify patients who might benefit from therapeutic-intensity anticoagulation. Methods: From March 1, 2020 to May 31, 2020, all patients admitted to the intensive care unit (ICU) for SARS-CoV-2 at Ospedale Regionale di Locarno, Locarno, Switzerland, were prospectively enrolled and screened daily with ultrasound for DVT. Following international consensus, a higher-intensity thromboprophylaxis was administered to all patients who were not at increased risk for bleeding. Sepsis-induced coagulopathy (SIC) and sequential organ failure assessment (SOFA) scores were calculated and time-to-DVT event in a COX proportional-hazard regression model was performed. A receiver operating characteristic (ROC) curve was used to determine sensitivity and specificity and the Youden's Index to establish the best threshold. Results: A total of 96 patients were enrolled. Deep venous thrombosis was detected in 37% of patients. Sepsis-induced coagulopathy and SOFA scores were both correlated to DVT. A SIC score of 1 vs. ≥2 showed a close association with DVT, with sensitivity, specificity, and positive and negative predictive values of 90.0, 48.1, and 49.1, and 89.7%, respectively. Most significantly though, a SOFA score of 1 or 2 points was shown to be the most accurate value in predicting the absence of DVT, indicating no need for therapeutic-intensity anticoagulation. Its sensitivity, specificity, and positive and negative predictive values were 87.9, 100, and 100, and 93.7%, respectively. The D-dimer test showed lower sensitivity and specificity whereas platelet count and aPTT were not found to be correlated to DVT. Conclusions: Patients with SOFA scores of 1 or 2 are at low risk of developing DVT and do not require therapeutic-intensity anticoagulation. Conversely, patients with scores ≥3 are at high risk of developing DVT.

Apixaban for Primary Prevention of Venous Thromboembolism in Patients With Multiple Myeloma Receiving Immunomodulatory Therapy

Immunomodulatory drugs (IMiDs), including thalidomide, lenalidomide, and pomalidomide, have improved survival of patients with multiple myeloma (MM). However, these therapies are associated with an increased risk of venous thromboembolism (VTE). Apixaban has been approved for treatment of acute VTE and for risk reduction of recurrent VTE following initial therapy. In this phase IV single-arm study (NCT02958969), we aim to prospectively evaluate the safety and efficacy of apixaban for primary prevention of VTE in patients with MM. The primary efficacy objective of this trial is to determine the rate of symptomatic VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE), over 6 months. The primary safety objective is to determine the rate of major bleeding in MM patients receiving apixaban prophylaxis. If proven safe and effective, apixaban will emerge as a promising option for oral VTE prophylaxis in MM patients.

Hemorrhage under veno-venous extracorporeal membrane oxygenation in acute respiratory distress syndrome patients: a retrospective data analysis

Background

Despite being still invasive and challenging, technical improvement has resulted in broader and more frequent application of extracorporeal membrane oxygenation (ECMO), to prevent hypoxemia and to reduce invasiveness of mechanical ventilation (MV). Heparin-coated ECMO-circuits are currently standard of care, in addition to heparin based anticoagulation (AC) regimen guided by activated clotting time (ACT) or activated partial thromboplastin time (aPTT). Despite these advances, a reliable prediction of hemorrhage is difficult and the risk of hemorrhagic complication remains unfortunately high. We hypothesized, that there are coagulation parameters that are indices for a higher risk of hemorrhage under veno-venous (VV)-ECMO therapy.

Methods

Data from 36 patients with severe respiratory failure treated with VV-ECMO at a University Hospital intensive care unit (ICU) were analyzed retrospectively. Patients were separated into two groups based on severity of hemorrhagic complications and transfusion requirements. The following data were collected: demographics, hemodynamic data, coagulation samples, transfusion requirements, change of ECMO-circuit during treatment and adverse effects, including hemorrhage and thrombosis.

Results

In this study 74 hemorrhagic events were observed, one third of which were severe. Patients suffering from severe hemorrhage had a lower survival rate on VV-ECMO (43% vs. 91%; P=0.002) and in ICU (36% vs. 86%; P=0.002). SAPS II, factor VII and X were different between mild and severe hemorrhage group.

Conclusions

Severe hemorrhage under VV-ECMO is associated with higher mortality. Only factor VII and X differed between groups. Further clinical studies are required to determine the timing of initiation and targets for AC therapies during VV-ECMO.