Direct oral anticoagulants: peri-operative considerations and controversies

The importance of perioperative optimisation to facilitate safe regional anaesthesia and their improved outcomes in fracture neck of femur patients

BACKGROUND

Hip fractures are common presentations to orthopaedic departments, and their surgical management often results in blood transfusions. Compared with general anaesthesia, regional anaesthesia reduces the need for transfusions and mortality in the wider surgical population.

AIMS

In hip fracture patients, our primary outcome measure was to examine any relationship between anaesthetic modality and transfusion rates. The secondary outcome measure was to assess the relationship between anaesthetic modality and one-year mortality.

METHODS

A retrospective cohort study of 280 patients was carried out in 2017 and 2018. Data were collected from patient records, local transfusion laboratory and the national hip fracture database.

RESULTS

A total of 59.6% had regional and 40.4% general anaesthesia. Regional anaesthesia patients were younger with fewer comorbidities (p < .05). About 19.8% regional and 34.5% general anaesthesia patients received transfusions (odds ratio (OR) = 0.47, p < .05); 13.6% were taking anticoagulants and were less likely to receive a regional anaesthetic (31.6% versus 64%, OR = 0.26, p < .05). One-year mortality was 27% for regional and 37% for general anaesthetic patients (OR = 0.64, p = .09).

CONCLUSION

Regional anaesthesia halved the risk of blood transfusion. Anticoagulated patients were 74% less likely to receive regional anaesthetics, but had no additional transfusion risk. With optimisation, a larger proportion of patients could have regional anaesthesia.

Enhanced Recovery After Cardiac Surgery

The aims of "Fast track" cardiac anesthesia including shortening time to tracheal extubation and to hospital discharge in selected patients. The evidence is weak and recommendations are mostly based on observational, nonrandomized data and expert opinion. The majority of outcomes studied include: time to tracheal extubation, hospital/ICU length of stay, procedure-related financial costs, and the type/amount of opioids used in the peri-operative period. There should be a shift in focus to generating higher quality evidence supporting the use of enhanced recovery protocols in cardiac surgical patients and finding ways to tailor enhanced recovery principles to all cardiac surgical patients. Research should focus on the quality of care for individual patients and the delivery of health care to the public.

The impact of direct oral anti-coagulants on hip fracture management : a systematic review and meta-analysis

Hip fractures are a common presentation in the elderly, a group who commonly have co-morbidities requiring the use of anticoagulants. Recently, direct oral anti-coagulants (DOAC) have become a popular method of anticoagulating patients. The primary aim of this review is to determine if the use of DOAC in elderly patients with hip fractures results in delays to theatre and/or an increased mortality risk. Major databases including Pubmed, MEDLINE and Embase were searched for relevant studies and the included studies reference lists were screened for further studies. A total of 6 studies were included in meta-analysis which was undertaken using RevMan software with 95% confidence interval (CI). Compared to control groups, patients who were anticoagulated with DOAC and required operative management of a hip fracture experienced a statistically significant delay to treatment. However independent analysis showed these patients did not experience an increased mortality risk when compared to the control group. While data is limited, treating clinicians should be comforted by these findings as operative manage- ment can be safely delayed to reduce the risk of intraoperative bleeding.

Heparin Anti-Xa Activity, a Readily Available Unique Test to Quantify Apixaban, Rivaroxaban, Fondaparinux, and Danaparoid Levels

BACKGROUND

Despite their usefulness in perioperative and acute care settings, factor-Xa inhibitor-specific assays are scarcely available, contrary to heparin anti-Xa assay. We assessed whether the heparin anti-Xa assay can (1) be used as a screening test to rule out apixaban, rivaroxaban, fondaparinux, and danaparoid levels that contraindicate invasive procedures according to current guidelines (>30 ng·mL-1, >30 ng·mL-1, >0.1 µg·mL-1, and >0.1 IU·mL-1, respectively), (2) quantify the anticoagulant level if found significant, that is, if it exceeded the abovementioned threshold.

METHODS

In the derivation cohort then in the validation cohort, via receiver operating characteristics (ROC) curve analysis, we evaluated the ability of heparin anti-Xa assay to detect levels of factor-Xa inhibitors above or below the abovementioned safety thresholds recommended for an invasive procedure (screening test). Among samples with relevant levels of factor-Xa inhibitor, we determined the conversion factor linking the measured level and heparin anti-Xa activity in a derivation cohort. In a validation cohort, the estimated level of each factor-Xa inhibitor was thus inferred from heparin anti-Xa activity. The agreement between measured and estimated levels of factor-Xa inhibitors was assessed.

RESULTS

Among 989 (355 patients) and 756 blood samples (420 patients) in the derivation and validation cohort, there was a strong linear relationship between heparin anti-Xa activities and factor-Xa inhibitors measured level (r = 0.99 [95% confidence interval {CI}, 0.99-0.99]). In the derivation cohort, heparin anti-Xa activity ≤0.2, ≤0.3, <0.1, <0.1 IU·mL-1 reliably ruled out a relevant level of apixaban, rivaroxaban, fondaparinux, and danaparoid, respectively (area under the ROC curve ≥0.99). In the validation cohort, these cutoffs yielded excellent classification accuracy (≥96%). If this screening test indicated relevant level of factor-Xa inhibitor, estimated and measured levels closely agreed (Lin's correlation coefficient close to its maximal value: 95% CI, 0.99-0.99). More than 96% of the estimated levels fell into the predefined range of acceptability (ie, 80%-120% of the measured level).

CONCLUSIONS

A unique simple test already widely used to assay heparin was also useful for quantifying these 4 other anticoagulants. Both clinical and economic impacts of these findings should be assessed in a specific study.

Effect of direct-acting oral anticoagulants (DOACs) on bleeding and blood product usage in cardiac surgery compared to warfarin and controls

In this retrospective, single-centre, observational study, we assessed (i) use of anticoagulant and antiplatelet (AP) therapy, (ii) the duration of direct-acting oral anticoagulant (DOAC) discontinuation, (iii) renal function and (iv) PT and APTT as predictors of bleeding and blood product usage; in adults (>18 years) undergoing major cardiac surgery from 01.01.2015 to 31.12.2018. Comparisons were made between each treatment group (warfarin, DOAC and DOAC + AP) and untreated controls, and between warfarin and DOAC. A total of 2928 patients were included for analysis. Median (range) of DOAC discontinuation prior to surgery was five days (1-22) for DOAC and five days (2-7) for DOAC + AP. There were no differences in bleeding between anticoagulant groups versus control, or DOAC versus warfarin. There were no differences in blood product use between DOAC and warfarin patients. The duration of DOAC discontinuation but not the creatinine clearance influenced bleeding and blood products use. Thrombosis occurred in 0·7% and 3·1% in controls and patients on warfarin respectively (P = 0·099) with none among patients on DOAC or DOAC + AP. The PT/APTT had no predictive value. Median five-day discontinuation of DOAC +/- AP irrespective of renal function prevents an increase in bleeding compared to patients on warfarin or controls with no increase in thrombosis.