Revisiting the International Normalized Ratio (INR) Threshold for Complications in Primary Total Knee Arthroplasty: An Analysis of 21,239 Cases

The effect of high-normal preoperative international normalized ratios on postoperative outcomes and complications following posterior cervical spine surgery

INTRODUCTION

Current guidelines recommend that the International Normalized Ratio (INR) be less than 1.5 prior to spine intervention. Recent studies have shown that an INR > 1.25 is associated worse outcomes following anterior cervical surgery. We sought to determine the risk of complications associated with an INR > 1.25 following elective posterior cervical surgery.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried. Patients undergoing elective posterior cervical surgery from 2012 to 2016 with an INR level within 24 h of surgery were included. Primary outcomes were hematoma requiring surgery, 30-day mortality, and transfusions within 72-hours. There were 815 patients in the INR ≤ 1 cohort (Cohort A), 410 patients in the 1 < INR ≤ 1.25 cohort (Cohort B), and 33 patients in the 1.25 < INR ≤ 1.5 cohort (Cohort C).

RESULTS

Cohort C had a higher rate of transfusion (4% Cohort A; 6% Cohort B; 12% Cohort C; p = 0.028) and the rate of mortality within 30 days postoperatively trended toward significance (0.4% Cohort A; 0.5% Cohort B; 3% Cohort C; p = 0.094). There was no significant difference in the rate of postoperative hematoma formation requiring surgery (0.2% Cohort A; 0% Cohort B; 0% Cohort C; p = 0.58). On multivariate analysis, increasing INR was not associated with an increased risk of developing a major complication.

CONCLUSION

An INR > 1.25 but ≤ 1.5 may be safe for posterior cervical surgery. An INR > 1.25 but ≤ 1.5 was associated with a significantly higher rate of transfusions. However, increasing INR was not significantly associated with increased risk of any of the major complications.

The historical origins of modern international normalized ratio targets

Prothrombin time (PT) and its derivative international normalized ratio (INR) are frequently ordered to assess the coagulation system. Plasma transfusion to treat incidentally abnormal PT/INR is a common practice with low biological plausibility and without credible evidence, yet INR targets appear in major clinical guidelines and account for the majority of plasma use at many institutions. In this article, we review the historical origins of INR targets. We recount historical milestones in the development of the PT, discovery of vitamin K antagonists (VKAs), motivation for INR standardization, and justification for INR targets in patients receiving VKA therapy. Next, we summarize evidence for INR testing to assess bleeding risk in patients not on VKA therapy and plasma transfusion for treating mildly abnormal INR to prevent bleeding in these patients. We conclude with a discussion of the parallels in misunderstanding of historic PT and present-day INR testing with lessons from the past that might help rationalize plasma transfusion in the future.

Carbon Monoxide as a Potential Therapeutic Agent: A Molecular Analysis of Its Safety Profiles

Carbon monoxide (CO) is endogenously produced in mammals, with blood concentrations in the high micromolar range in the hemoglobin-bound form. Further, CO has shown therapeutic effects in various animal models. Despite its reputation as a poisonous gas at high concentrations, we show that CO should have a wide enough safety margin for therapeutic applications. The analysis considers a large number of factors including levels of endogenous CO, its safety margin in comparison to commonly encountered biomolecules or drugs, anticipated enhanced safety profiles when delivered via a noninhalation mode, and the large amount of safety data from human clinical trials. It should be emphasized that having a wide enough safety margin for therapeutic use does not mean that it is benign or safe to the general public, even at low doses. We defer the latter to public health experts. Importantly, this Perspective is written for drug discovery professionals and not the general public.

A simple machine learning model for the prediction of acute kidney injury following noncardiac surgery in geriatric patients: a prospective cohort study

BACKGROUND

Surgery in geriatric patients often poses risk of major postoperative complications. Acute kidney injury (AKI) is a common complication following noncardiac surgery and is associated with increased mortality. Early identification of geriatric patients at high risk of AKI could facilitate preventive measures and improve patient prognosis. This study used machine learning methods to identify important features and predict AKI following noncardiac surgery in geriatric patients.

METHODS

The data for this study were obtained from a prospective cohort. Patients aged ≥ 65 years who received noncardiac surgery from June 2019 to December 2021 were enrolled. Data were split into training set (from June 2019 to March 2021) and internal validation set (from April 2021 to December 2021) by time. The least absolute shrinkage and selection operator (LASSO) regularization algorithm and the random forest recursive feature elimination algorithm (RF-RFE) were used to screen important predictors. Models were trained through extreme gradient boosting (XGBoost), random forest, and LASSO. The SHapley Additive exPlanations (SHAP) package was used to interpret the machine learning model.

RESULTS

The training set included 6753 geriatric patients. Of these, 250 (3.70%) patients developed AKI. The XGBoost model with RF-RFE selected features outperformed other models with an area under the precision-recall curve (AUPRC) of 0.505 (95% confidence interval [CI]: 0.369-0.626) and an area under the receiver operating characteristic curve (AUROC) of 0.806 (95%CI: 0.733-0.875). The model incorporated ten predictors, including operation site and hypertension. The internal validation set included 3808 geriatric patients, and 96 (2.52%) patients developed AKI. The model maintained good predictive performance with an AUPRC of 0.431 (95%CI: 0.331-0.524) and an AUROC of 0.845 (95%CI: 0.796-0.888) in the internal validation.

CONCLUSIONS

This study developed a simple machine learning model and a web calculator for predicting AKI following noncardiac surgery in geriatric patients. This model may be a valuable tool for guiding preventive measures and improving patient prognosis.

TRIAL REGISTRATION

The protocol of this study was approved by the Committee of Ethics from West China Hospital of Sichuan University (2019-473) with a waiver of informed consent and registered at www.chictr.org.cn (ChiCTR1900025160, 15/08/2019).

The Relationship Between Preoperative International Normalized Ratio and Postoperative Major Bleeding in Total Shoulder Arthroplasty

INTRODUCTION

This study aimed to assess the relationship between preoperative international normalized ratio (INR) levels and major postoperative bleeding events after total shoulder arthroplasty (TSA).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried for TSA from 2011 to 2020. A final cohort of 2405 patients with INR within 2 days of surgery were included. Patients were stratified into four groups: INR ≤ 1.0, 1.0 < INR ≤ 1.25, 1.25< INR ≤ 1.5, and INR > 1.5. The primary outcome was bleeding requiring transfusion within 72 hours, and secondary outcome variables included complication, revision surgery, readmission, and hospital stay duration. Multivariable logistic and linear regression analyses adjusted for relevant comorbidities were done.

RESULTS

Of the 2,405 patients, 48% had INR ≤ 1.0, 44% had INR > 1.0 to 1.25, 7% had INR > 1.25 to 1.5, and 1% had INR > 1.5. In the adjusted model, 1.0 < INR ≤ 1.25 (OR 1.7, 95% CI 1.176 to 2.459), 1.25 < INR ≤ 1.5 (OR 2.508, 95% CI 1.454 to 4.325), and INR > 1.5 (OR 3.200, 95% CI 1.233 to 8.302) were associated with higher risks of bleeding compared with INR ≤ 1.0.

DISCUSSION

The risks of thromboembolism and bleeding lie along a continuum, with higher preoperative INR levels conferring higher postoperative bleeding risks after TSA. Clinicians should use a patient-centered, multidisciplinary approach to balance competing risks.

The Effect of High-Normal Preoperative International Normalized Ratios on Outcomes and Complications After Anterior Cervical Spine Surgery

Hematoma after anterior cervical spine surgery can result in neurologic and airway compromise. Current guidelines recommend an international normalized ratio (INR) <1.5 before elective spine surgery because of increased complications. The risk associated with an INR of 1.25 is not well studied. The purpose of this study was to determine the risk of complications associated with a preoperative INR >1.25 and ≤1.5 in patients undergoing elective anterior cervical spine surgery. The American College of Surgeons National Surgical Quality Improvement Program database was queried. Patients undergoing elective anterior cervical spine surgery from 2012 to 2016 who had an INR recorded within 24 hours of surgery were included. Outcomes of interest included postoperative hematoma requiring surgery, 30-day mortality, and 30-day readmissions and reoperations. A total of 2949 patients were included. The incidence of a postoperative hematoma that required surgical management was 0.2%, 0.6%, and 4.5% in the INR≤1, 11.25 and ≤1.5 before elective anterior cervical spine surgery is associated with significantly higher rates of postoperative hematoma formation as well as 30-day readmission and reoperation; there was a trend toward significance in mortality rate. [Orthopedics. 2024;47(1):e26-e32.].

The influence of elevated international normalized ratio on complications following total shoulder arthroplasty

Background

Identifying preoperative risk factors for complications following total shoulder arthroplasty (TSA) has both clinical and financial implications. The purpose of this study was to determine the influence of different degrees of preoperative INR elevation on complications following TSA.

Methods

Patients undergoing primary TSA from 2007 to 2018 were identified in a national database. Patients were stratified into 4 cohorts: INR of <1.0, INR of >1.0 to 1.25, INR of >1.25 to 1.5, and INR of >1.5. Postoperative complications were assessed. Multivariate logistic regressions were performed to adjust for differences in demographics and comorbidities among the INR groups.

Results

Following adjustment and relative to patients with an INR of <1.0, those with INR of >1.0-1.25, >1.25-1.5, and >1.5 had 1.6-times, 2.4-times, and 2.8-times higher odds of having postoperative bleeding requiring transfusion, respectively (p < 0.05 for all). Relative to patients with INR <1.0, those with INR of > 1.25-1.5 and INR of >1.5 had 7.8-times and 7.0-times higher odds of having pulmonary complications, respectively (p < 0.05 for both).

Discussion

With increasing INR levels, there is an independent and step-wise increase in odd ratios for postoperative complications. Current guidelines for preoperative INR thresholds may need to be adjusted for more predictive risk-stratification for TSA.

Level of Evidence

III.

Determining a preoperative international normalised ratio threshold safe for hip fracture surgery

INTRODUCTION

The purpose of this study was first, to assess the relationship between preoperative INR (international normalised ratio) and postoperative complication rates in patients with a hip fracture, and second, to establish a threshold for INR below which the risk of complications is comparable to those in patients with a normal INR.

METHODS

We retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program and found 35,910 cases who had undergone surgery for a hip fracture between 2012 and 2018. Cases were stratified into 4 groups based on their preoperative INR levels: <1.4; ⩾1.4 and <1.6; ⩾1.6 and <1.8 and ⩾1.8. These cohorts were assessed for differences in preoperative factors, intraoperative factors, and postoperative course. Multivariate logistic regression was used to assess the risk of transfusion, 30-day mortality, cardiac complications, and wound complications adjusting for all preoperative and intraoperative factors.

RESULTS

Of the 35,910 cases, 33,484 (93.2%) had a preoperative INR < 1.4; 867 (2.4%) an INR ⩾1.4 and <1.6; 865 (2.4%) an INR ⩾ 1.6 and <1.8 and 692 (1.9%) an INR ⩾ 1.8. A preoperative INR ⩾ 1.8 was independently associated with an increased risk of bleeding requiring transfusion. A preoperative INR ⩾ 1.6 was associated with an increased risk of mortality.

CONCLUSIONS

We found that an INR of <1.6 is a safe value for patients who are to undergo surgery for a hip fracture. Below this value, patients avoid an increased risk of both transfusion and 30-day mortality seen with higher INR values. These findings may allow adjustment of preoperative protocols and improve the outcome of hip fracture surgery in this group of patients.

The international normalised ratio predicts perioperative complications in revision total hip arthroplasty

BACKGROUND

Standard preoperative protocols in total joint arthroplasty utilise the international normalised ratio (INR) to determine patient coagulation profiles. However, the relevance of preoperative INR values in joint arthroplasty remains controversial. Therefore, we examined (1) the relationship between preoperative INR values and various outcome measures, including, but not limited to: surgical site complications, medical complications, bleeding, number of readmissions, and mortality. Additionally, we sought to determine (2) specific INR values associated with these complications and (3) cutoff INR levels which correlated with specific outcomes. We additionally applied these analyses to (4) examine the relationship between INR and length-of-stay (LOS).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database (ACS-NSQIP) was queried for rTHA procedures performed between 2006 and 2017. INR ranges were used to stratify cohorts: ⩽1.0, 1.0-⩽1.25, 1.25-⩽1.5, >1.5. INR values were determined using receiver operating characteristics (ROC) curves for each outcome of interest. Optimal cutoff INR values for each outcome were then obtained using univariate/multivariate models. 2012 patients who underwent rTHA met inclusion criteria.

RESULTS

Patients with progressively higher INR values had a significantly different risk of mortality within 30 days (p = 0.005), bleeding requiring transfusion (p < 0.001), sepsis (p = 0.002), stroke (p < 0.001), failure to wean from ventilator within 48 hours (p = 0.001), readmission (p = 0.01), and hospital length of stay (p < 0.001). Similar results were obtained when utilising optimal INR cutoff values. When correcting for other factors, the following poor outcomes were significantly associated with the respective INR cutoff values (Estimate, 95% CI, p-value): LOS >4 days (1.67, 1.34-2.08, p < 0.001), bleeding requiring transfusion (1.65, 1.30-2.09, p < 0.001), sepsis (2.15, 1.11-4.17, p = 0.022), and any infection (1.82, 1.01-3.29, p = 0.044).

CONCLUSIONS

Our analysis illustrates a direct relationship between specific preoperative INR levels and poor outcomes following rTHA, including increased LOS, transfusion requirements and infection. Therefore, current INR guideline targets may need to be re-examined when optimising patients for revision arthroplasty.

Complications and predictors of morbidity for hip fracture surgery in patients with chronic liver disease

BACKGROUND

Despite the fact that patients with chronic liver disease (CLD) are at increased risk of complications after a fracture of the hip, there remains little information about the risk factors for acute postoperative complications and their overall outcome.The aim of this study was to describe inpatient postoperative complications and identify predictors of postoperative morbidity.

METHODS

Patients with CLD who had been treated for a fracture of the hip between April 2005 and August 2019 were identified from a retrospective search of an intramural trauma registry based in the Northeastern United States. Medical records were reviewed for baseline demographics, preoperative laboratory investigations, and outcomes.

RESULTS

The trauma registry contained 110 patients with CLD who had undergone surgery for a fracture of the hip. Of these, patients with a platelet-count of ⩽100,000/µL were 3.81 (95% CI, 1.59-9.12) times more likely to receive a transfusion than those with a platelet-count of >100,000/µL. Those with a Model for End-stage Liver Disease (MELD) score of >9 were 5.54 (2.33-13.16) times more likely to receive a transfusion and 3.97 (1.06-14.81) times more likely to develop postoperative delirium than those with a MELD score of ⩽9.Of patients without chronic kidney disease, those with a creatinine of ⩾1.2 mg/dL were 6.80 (1.79-25.87) times more likely to develop acute renal failure (ARF) than those with a creatinine of <1.2 mg/dL. In a multivariable model, as MELD score was increased, the odds of developing a composite postoperative complication, which included transfusion, ARF, delirium, or deep wound infection, were 1.29 (1.01-1.66). Other tools used to assess surgical risks, Charlson Comorbidity Index, Elixhauser, and American Society of Anesthesiologist scores, were not predictive.

CONCLUSIONS

Patients with CLD who undergo surgery for a hip fracture have a high rate of postoperative complications which can be predicted by the preoperative laboratory investigations identified in this study and MELD scores, but not by other common comorbidity indices.

Bone Density May Be a Promising Predictor for Blood Loss during Total Hip Arthroplasty

Background: Total hip arthroplasty (THA), which is performed mostly in elderly individuals, can result in substantial blood loss and thereby imposes a significant physical burden and risk of blood transfusion. The femoral neck cut and reamed acetabulum are the main sites of intraoperative bleeding. Whether the bone density in that region can be used to predict the amount of blood loss in THA is unknown. Methods: We retrospectively analyzed adult patients undergoing primary THA in the Department of Orthopedics, Peking Union Medical College Hospital, from January 2018 to January 2020. All these patients underwent primary unilateral THA. Patients had their bone mineral density (BMD) recorded within the week before surgery and were stratified and analyzed for perioperative blood loss. Multivariable regressions were utilized to adjust for differences in demographics and comorbidities among groups. Results: A total of 176 patients were included in the study. Intraoperative blood loss was 280.1 ± 119.56 mL. Pearson correlation analysis showed a significant correlation between blood loss and preoperative bone density of both the femoral greater trochanter (R = 0.245, p = 0.001) and the Ward’s triangle (R = 0.181, p = 0.016). Stepwise multiple linear regression showed that preoperative bone density of the greater trochanter (p = 0.015, 95% CI: 0.004–0.049) and sex (p = 0.002) were independent risk factors for THA bleeding. The area under the receiver operating characteristic curve (AUROC) of the greater trochanter and Ward’s triangle was 0.593 (95% CI: 0.507–0.678, p = 0.035) and 0.603 (95% CI: 0.519–0.688, p = 0.018), respectively. The cutoff T value on the femoral greater trochanter for predicting higher bleeding was −1.75. Conclusions: In THA patients, preoperative bone density values of the femoral greater trochanter and sex could be promising independent predictors for bleeding during surgery. Osteoporosis and female patients might have lower blood loss in the THA operation.

Blood Management in Total Knee Arthroplasty: A Nationwide Analysis from 2011 to 2018

Both advances in perioperative blood management, anesthesia, and surgical technique have improved transfusion rates following primary total knee arthroplasty (TKA), and have driven substantial change in preoperative blood ordering protocols. Therefore, blood management in TKA has seen substantial changes with the implementation of preoperative screening, patient optimization, and intra- and postoperative advances. Thus, the purpose of this study was to examine changes in blood management in primary TKA, a nationwide sample, to assess gaps and opportunities. The American College of Surgeons National Surgical Quality Improvement Program database was used to identify TKA (n = 337,160) cases from 2011 to 2018. The following variables examined, such as preoperative hematocrit (HCT), anemia (HCT <35.5% for females and <38.5% for males), platelet count, thrombocytopenia (platelet count < 150,000/µL), international normalized ration (INR), INR > 2.0, bleeding disorders, preoperative, and postoperative transfusions. Analysis of variances were used to examine changes in continuous variables, and Chi-squared tests were used for categorical variables. There was a substantial decrease in postoperative transfusions from high of 18.3% in 2011 to a low of 1.0% in 2018, (p < 0.001), as well as in preoperative anemia from a high of 13.3% in 2011 to a low of 9.5% in 2016 to 2017 (p < 0.001). There were statistically significant, but clinically irrelevant changes in the other variables examined. There was a HCT high of 41.2 in 2016 and a low of 40.4 in 2011 to 2012 (p < 0.001). There was platelet count high of 247,400 in 2018 and a low of 242,700 in 201 (p < 0.001). There was a high incidence of thrombocytopenia of 5.2% in 2017 and a low of low of 4.4% in 2018 (p < 0.001). There was a high INR of 1.037 in 2011 and a low of 1.021 in 2013 (p < 0.001). There was a high incidence of INR >2.0 of 1.0% in 2012 to 2015 and a low of 0.8% in 2016 to 2018 (p = 0.027). There was a high incidence of bleeding disorders of 2.9% in 2013 and a low of 1.8% in 2017 to 2018 (p < 0.001). There was a high incidence of preoperative transfusions of 0.1% in 2011 to 2014 and a low of <0.1% in 2015 to 2018 (p = 0.021). From 2011 to 2018, there has been substantial decreases in patients receiving postoperative transfusions after primary TKA. Similarly, although a decrease in patients with anemia was seen, there remains 1 out 10 patients with preoperative anemia, highlighting the opportunity to further improve and address this potentially modifiable risk factor before surgery. These findings may reflect changes during TKA patient selection, optimization, or management, and emphasizes the need to further advance multimodal approaches for perioperative blood management of TKA patients. This is a Level III study.

Analysis of the Dose-Response Relationship Between the International Normalized Ratio and Hepatic Encephalopathy in Patients With Liver Cirrhosis Using Restricted Cubic Spline Functions

Background

The International Normalized Ratio (INR) is significantly associated with Hepatic Encephalopathy (HE) in patients with liver cirrhosis. However, the dose-response relationship between continuous INR changes and HE risk has not been clearly defined. Thus, our goal was to explore the continuous relationship between HE and INR among patients hospitalized with liver cirrhosis and to evaluate the role of the INR as a risk factor for HE in these patients.

Methods

A total of 6,266 people were extracted from the Big Data Platform of the Medical Data Research Institute of Chongqing Medical University. In this study, unconditional logistic regression and restricted cubic spline (RCS) model were used to analyze the dose-response association of INR with HE. Alcoholic liver disease, smoking status, and drinking status were classified for subgroup analysis.

Results

The prevalence of HE in the study population was 8.36%. The median INR was 1.4. After adjusting for alcoholic liver disease, age, smoking status, drinking status, total bilirubin, neutrophil percentage, total hemoglobin, aspartate aminotransferase, serum sodium, albumin, lymphocyte percentage, serum creatinine, red blood cell, and white blood cell, multivariate logistic regression analysis revealed that INR ≥ 1.5 (OR = 2.606, 95% CI: 2.072–3.278) was significantly related to HE risk. The RCS model showed a non-linear relationship between the INR and HE (non-linear test, χ² = 30.940, P < 0.001), and an increased INR was an independent and adjusted dose-dependent risk factor for HE among patients with liver cirrhosis.

Conclusion

This finding could guide clinicians to develop individualized counseling programs and treatments for patients with HE based on the INR risk stratification.

Impact of extracorporeal photopheresis on blood and coagulation parameters

Extracorporeal photopheresis (ECP) is considered a safe treatment modality. We aimed to assess blood parameters including coagulation during ECP over time. We performed a long-term retrospective single-center chart review (laboratory parameters) of adult patients (n = 172) who had received ECP for any indication. We observed a significant decrease (P < 0.05) in erythrocytes, hemoglobin, and leukocytes compared to baseline levels after only one ECP procedure. This decrease persisted after 3-, 6-, 9-, and 12-months of ECP. A significant pathological decline of hemoglobin was observed in a higher proportion (26.4% and 25.2%, respectively) of patients after 6 (P = 0.0007) and 12 (P = 0.012) months of ECP. Mean corpuscular volume as well as hematocrit was significantly decreased at 3-, 6-, 9-, and 12-months of evaluation compared to baseline (P < 0.05). After 9 and 12 months of ECP we observed a further decline in lymphocyte counts (P < 0.05). Various coagulation parameters did not change significantly during ECP treatment. Even though not all alterations observed in peripheral blood of ECP patients in the present study were of clinical significance, risk for developing persistent anemia must be considered in patients undergoing ECP. This article is protected by copyright. All rights reserved.

Regional anaesthesia in patients on antithrombotic drugs: Joint ESAIC/ESRA guidelines

BACKGROUND

Bleeding is a potential complication after neuraxial and peripheral nerve blocks. The risk is increased in patients on antiplatelet and anticoagulant drugs. This joint guideline from the European Society of Anaesthesiology and Intensive Care and the European Society of Regional Anaesthesia aims to provide an evidence-based set of recommendations and suggestions on how to reduce the risk of antithrombotic drug-induced haematoma formation related to the practice of regional anaesthesia and analgesia.

DESIGN

A systematic literature search was performed, examining seven drug comparators and 10 types of clinical intervention with the outcome being peripheral and neuraxial haematoma. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used for assessing the methodological quality of the included studies and for formulating recommendations. A Delphi process was used to prepare a clinical practice guideline.

RESULTS

Clinical studies were limited in number and quality and the certainty of evidence was assessed to be GRADE C throughout. Forty clinical practice statements were formulated. Using the Delphi-process, strong consensus (>90% agreement) was achieved in 57.5% of recommendations and consensus (75 to 90% agreement) in 42.5%.

DISCUSSION

Specific time intervals should be observed concerning the adminstration of antithrombotic drugs both prior to, and after, neuraxial procedures or those peripheral nerve blocks with higher bleeding risk (deep, noncompressible). These time intervals vary according to the type and dose of anticoagulant drugs, renal function and whether a traumatic puncture has occured. Drug measurements may be used to guide certain time intervals, whilst specific reversal for vitamin K antagonists and dabigatran may also influence these. Ultrasound guidance, drug combinations and bleeding risk scores do not modify the time intervals. In peripheral nerve blocks with low bleeding risk (superficial, compressible), these time intervals do not apply.

CONCLUSION

In patients taking antiplatelet or anticoagulant medications, practitioners must consider the bleeding risk both before and after nerve blockade and during insertion or removal of a catheter. Healthcare teams managing such patients must be aware of the risk and be competent in detecting and managing any possible haematomas.

Factors Affecting 30-Day Mortality following Primary Elective Total Knee Arthroplasty: A Database Study of 326,157 Patients

Despite its rarity, the risk of mortality following primary elective total knee arthroplasty (TKA) is a critical component of surgical decision-making and patient counseling. The purpose of our study was to (1) determine the overall 30-day mortality rate for unilateral primary elective TKA patients, (2) determine the 30-day mortality rates when stratified by age, comorbidities, and preoperative diagnosis, and (3) identify the distribution of (i) patient demographics, (ii) baseline comorbidities, and (iii) preoperative diagnoses between mortality and mortality-free cohorts. A total of 326,157 patients underwent primary elective TKA (2011-2018) were identified through retrospective review of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients were divided into 30-day mortality (n = 320) and mortality-free (n = 325,837) cohorts. Patient demographics, preoperative comorbidities, and preoperative diagnoses were compared. Age group, American Society of Anesthesiology (ASA) score, and modified Charlson Comorbidity Index (CCI) scores were normalized per 1000 and stratified by preoperative diagnosis. The overall mortality rate was 0.098%. Older age (p < 0.001) and male gender (p < 0.001) were associated with increased mortality. There was no association between mortality and race (p = 0.346) or body mass index (BMI) class (p = 0.722). All reported comorbidities except smoking status were significantly greater in the mortality cohort (p < 0.05). For ASA scores of I, II, III, and IV, the number of deaths per 1,000 were 0.16, 0.47, 1.4, and 4.4, respectively. For CCI scores of 0, 1, 2, 3, 4, and 6, mortality rates per 1,000 were 0.76, 2.1, 7.0, 11, 29, and 7.6, respectively. Mortality rates for a preoperative diagnosis of osteoarthritis (OA) versus non-OA were, respectively, 0.096% and 0.19% (p < 0.001). Increased age, male gender, increased comorbidity burden, and non-OA preoperative diagnoses are associated with higher rates of 30-day postoperative mortality. There were no significant associations between BMI or race and 30-day mortality. These findings aid in identifying of higher-risk patients, who can then receive appropriate counseling or preoperative interventions to reduce the risk of perioperative mortality.

Effect of an Elevated Preoperative International Normalized Ratio on Transfusion and Complications in Primary Total Hip Arthroplasty with the Enhanced Recovery after Surgery Protocol

Objective

To verify whether an elevated preoperative international normalized ratio (INR) increases transfusion and complications independently in primary total hip arthroplasty (THA) with the management of an enhanced recovery after surgery (EARS) protocol.

Methods

We retrospectively reviewed the database of adults who underwent primary THA between 2014 and 2018 by the same surgeon. A total of 552 patients were assigned into three groups by preoperative INR class: INR ≤ 0.9, 0.9 < INR < 1.0, and INR ≥ 1.0. We regarded transfusion within 90 days during the same hospitalization as the primary outcome. We also included perioperative blood loss, maximum Hb drop, postoperative anaemia requiring medicine, and length of hospital stay (LOS) during the same hospitalization in the study. Complications and reoperation at 90 days and mortality at 90 days and 12 months were also included in the study. Univariable analyses were utilized to compare baselines and outcomes among the three groups. Multivariate logistic regressions were used to adjust for differences at baseline among the groups.

Results

All patients had an INR < 1.5 preoperatively and were managed with the ERAS protocol. Among them, 93 (16.8%) patients had INR ≤ 0.9, 268 (48.6%) patients had 0.9 < INR < 1.0, and 191 (34.6%) patients had INR ≥ 1.0. In the univariable analyses, as the INR increased, the transfusion rates increased from 1.08% for INR ≤ 0.9, to 1.12% for 0.9 < INR < 1.0 and to 5.76% for INR ≥ 1.0 (P < 0.05). The overall complication rate increased from 10.8% for INR ≤ 0.9, to 16.4% for 0.9 < INR < 1.0, and to 22.5% for INR ≥ 1.0 (P < 0.05). The length of stay (LOS) in the INR ≥ 1.0 group was 5.7 ± 2.2 days, which was significantly longer than that in the INR ≤ 0.9 group (4.7 ± 1.6 days, P = 0.000) and 0.9 < INR < 1.0 group (5.1 ± 2.0 days, P = 0.007). No statistical significance was detected among the groups regarding blood loss, maximum Hb drop, or the incidence of postoperative anaemia that required medicine. There was no significant difference in reoperation or mortality among the groups. When controlling for demographic and comorbidity characteristics, there was no statistically significant difference in the odds of transfusion during the same hospitalization or overall complications at 90 days among the groups (P > 0.05).

Conclusions

Elevated preoperative INR cannot increase transfusion or complication rates independently in primary THA with the management of the ERAS protocol. With the improvement in the ERAS protocol and the use of tranexamic acid (TXA), an INR < 1.5 is still a conventional safe threshold for THA surgery.

Abnormal Coagulation as a Risk Factor for Postoperative Complications After Primary and Revision Total Hip and Total Knee Arthroplasty

BACKGROUND

Patients undergoing total joint arthroplasty (TJA) have an increased likelihood of having an abnormal coagulation profile compared with the general population. Coagulation abnormalities are often screened for before surgery and considered during perioperative planning. This study assesses a preoperative abnormal coagulation profile as a risk factor for postoperative complications after total hip arthroplasty (THA), revision THA (rTHA), total knee arthroplasty (TKA), and revision TKA (rTKA) and then examines specific coagulopathies to determine their influence on complication rates.

METHODS

Patients who underwent THA, rTHA, TKA, or rTKA from 2011 to 2017 were identified in the American College of Surgeons National Surgical Quality Improvement Program database and then assessed for preoperative abnormal coagulation profiles. Various postoperative complications were analyzed for each cohort, and two separate multivariate regression analyses were used to assess the relationship between abnormal coagulation and postoperative complications.

RESULTS

403,566 THA, rTHA, TKA, or rTKA cases were identified, and 40,466 (10.0%) of patients were found to have an abnormal coagulation profile. Patients with preoperative coagulation abnormalities had higher likelihoods of postoperative complications after primary TJA than in revision TJA. An international normalized ratio>1.2 was associated with the most types of postoperative complications, followed by a bleeding disorder diagnosis. A partial thromboplastin time>35 seconds was associated with only one type of postoperative complication, while a platelet count <150,000 per μL was associated with postoperative complications only after TKA.

CONCLUSION

TJA in patients with abnormal coagulation profiles may result in adverse outcomes. These patients may benefit from preoperative intervention. Prophylactic care needs to be personalized to the specific coagulation abnormalities present.

Operative Times in Primary Total Knee Arthroplasty: Can We Predict the Future Based on Contemporary Nationwide Data

Recently, the Centers for Medicare & Medicaid Services announced its decision to review "potentially misvalued" Current Procedural Terminology (CPT) codes, including those for primary total knee arthroplasty (TKA). CPT 27447 is being reevaluated to determine contemporary relative value units for work value, with operative time considered a primary factor in this revaluation. Despite broader indications for TKA, including extension of the procedure to more complex patient populations, it is unknown whether operative times may remain stable in the future. Therefore, the purpose of this study was to specifically evaluate future trends in TKA operative times across a large sample from a national database. The American College of Surgeons National Surgical Quality Improvement Project database was queried from January 1, 2008 to December 31, 2017 to identify 286,816 TKAs using the CPT code 27447. Our final analysis included 140,890 TKAs. Autoregressive integrated moving average forecasting models were built to predict 2- and 10-year operative times. While operative times were significantly different between American Society of Anesthesiologists (ASA) classes 1 and 2 (p = 0.035), there were not enough patients in ASA class 1 to perform rigorous inference. Additionally, operative times were not significantly different between ASA classes 3 and the combined ASA classes 4 and 5 cohort (p = 0.95). Therefore, we were only able to perform forecasts for ASA classes 2 and 3. Operative time was found to be nonstationary for both ASA class 2 (p = 0.08269) and class 3 (p = 0.2385). As a whole, the projection models indicated that operative time will remain within 2 minutes of the present operative time, up to the year 2027. Our projections indicate that operative times will remain stable over the next decade. This suggests that there is a lack of evidence for reducing the valuation of CPT code 27477 based on intraservice time for TKA. Further study should examine operative time trends in the setting of evolving alternative payment models, increasing patient complexity, and governmental restrictions.

Acute compartment syndrome caused by hematoma after shoulder surgery: a case series

BACKGROUND

The development of acute compartment syndrome (ACS) of the upper extremity after an elective surgical shoulder procedure is rare but can have devastating results. We describe a series of patients who developed ACS of the upper extremity caused by hematoma formation and subsequent upper extremity swelling after undergoing elective surgical shoulder procedures.

METHODS

We retrospectively reviewed the database of our tertiary care institution between 2004 and 2019 to find patients who developed ACS after elective shoulder surgery. We found 4 such patients and reviewed their medical records and extracted data on their history, clinical examination, predisposing factors, treatment, and clinical and radiographic outcomes.

RESULTS

Of the 4 patients treated, 2 had undergone reverse total shoulder arthroplasty, 1 had undergone open biceps tenodesis, and 1 had undergone closed manipulation for adhesive capsulitis. Two patients developed symptoms of ACS within 24 hours of the index procedure. Both were treated with immediate decompression of the hematoma, and both experienced complete pain relief and full recovery of function at 1-year follow-up. Two patients were on anticoagulation therapy. Of these, 1 patient developed ACS symptoms 14 days after a revision reverse total shoulder arthroplasty and was treated successfully with compartment release. Despite treatment, the other patient developed extensive necrosis of muscles and nerves in the upper extremity and severe neurologic deficits in hand and forearm function.

CONCLUSION

ACS of the upper extremity caused by hematoma formation can lead to catastrophic outcomes if diagnosis and treatment are not immediate. Providers should be aware of ACS and the need for prompt diagnosis and treatment.

The Association of International Normalized Ratio with Postoperative Complications in Revision Total Knee Arthroplasty

The purpose of this study was to examine the relationship between elevated preoperative international normalized ratio (INR) and (1) mortality, (2) postoperative bleeding, and (3) other postoperative complications in a national cohort of patients who underwent revision total knee arthroplasty (rTKA). The American College of Surgeons National Surgical Quality Improvement Program was queried for rTKA procedures conducted between 2006 and 2017. Cohorts were based on INR ranges: <1, 1 < INR ≤ 1.25, 1.25 < INR ≤ 1.5, and >1.5. Univariate/multivariate statistics were calculated to analyze associations between INR value and designated covariates. These statistics were additionally applied to optimal cutoff values of INR calculated using a receiver operating characteristics curve. The final cohort consisted of 1,676 patients. Progressively higher INR values were associated with an increased risk of mortality within 30 days (p < 0.006), bleeding requiring transfusion (p < 0.001), sepsis (p < 0.001), return to the operating room (Odds Ratio [OR], p = 0.011), reintubation (p < 0.001), pneumonia (p < 0.001), failure to wean from mechanical ventilation ≤48 hours (p < 0.001), acute renal failure (p = 0.001), and hospital length of stay (LOS). Statistically significant associations were similarly seen when calculated optimal INR values were used. Optimal INR turn point was found to be associated with a significant increased risk of long LOS (optimal INR = 1.03, OR: 1.7, 95% confidence interval [CI]: 1.33-2.18; p < 0.001) and a significant decreased risk of bleeding requiring transfusion (INR = 1.005, OR: 0.732, 95% CI: 0.681-0.786; p < 0.001). High preoperative INR values were independently and significantly associated with an increased risk of multiple postoperative complications. Current guidelines for INR <1.5 should be reassessed for patients undergoing rTKA.

Preoperative Platelet and International Normalized Ratio Thresholds and Risk of Complications After Primary Hip Fracture Surgery

BACKGROUND

A paucity of data exists on safe platelet and international normalized ratio (INR) thresholds for hip fracture surgery. Recent work has called into question the safety of preoperative INRs < 1.5 for total knee arthroplasty, and optimal platelet thresholds are unknown. The purpose of this study was to identify the risk of 30-day postoperative morbidity and mortality in patients with thrombocytopenia or elevated INRs undergoing hip fracture surgery.

METHODS

The National Surgical Quality Improvement Program database was queried for patients undergoing surgical treatment of a native hip fracture from 2012 to 2017 (N = 86,850). Patient demographic, laboratory, and complication data were collected. Patients with preoperative platelet counts or INRs within one day of surgery were included for analysis. Preoperative platelet counts and INRs were divided into four groups (<50 k/μL, ≥50 k to 100 k/μL, ≥100 k to 150 k/μL, ≥150 k/μL, and ≤1.0, >1.0 to 1.5, >1.5 to 2.0, and >2.0, respectively). Multivariable logistic regressions were used to assess the independent association between platelet count and INR on bleeding complications requiring transfusion, wound complications, reoperations, readmissions, and deaths.

RESULTS

A total of 72,306 and 56,027 patients were included for analysis of preoperative platelet and INR levels, respectively. In reference to platelet levels ≥150 k/μL, a notably increased risk of bleeding events was observed for patients with platelet counts ≥100 k to 150 k/μL (odds ratio [OR] 1.21, 95% confidence interval 1.15 to 1.27), ≥50 to 100 k/μL (OR 1.85, 1.69 to 2.03), and <50 k/μL (OR 1.60, 1.25 to 2.04). Decreasing platelet counts were associated with a stepwise increased risk of mortality from OR 1.12 (1.02 to 1.22) for platelet counts ≥100 k to 150 k/μL to OR 1.63 (1.41 to 1.90) and OR 1.59 (1.06 to 2.39) for platelet counts ≥50 k to 100 k/μL and <50 k/μL, respectively. Elevated INR was associated with an increased risk of reoperations, readmissions, and death (P < 0.001 for all), with largest effect sizes observed starting at INRs >1.5.

DISCUSSION

The results of this study suggest that preoperative platelet thresholds of <100,000/μL and INR thresholds of 1.5 serve as an important risk factor for complications after hip fracture surgery. Future work is warranted to determine whether preoperative platelet transfusions and/or INR reversal will improve outcomes for these patients.

LEVEL OF EVIDENCE

Prognostic Level III.

Operative times in primary total hip arthroplasty will remain stable up to the year 2027: prediction models based on 85,808 cases

PURPOSE

Recently, the Centers for Medicare and Medicaid have announced the decision to review "potentially misvalued" Current Procedural Terminology codes, including those for primary total hip arthroplasty (THA). While recent studies have suggested that THA operative times have remained stable in recent years, there is an absence of information regarding how operative times are expected to change in the future. Therefore, the purpose of our analysis was to produce 2- and 10-year prediction models developed from contemporary operative time data.

METHODS

Utilizing the American College of Surgeons National Surgical Quality Improvement patient database, all primary THA procedures performed between January 1st, 2008 and December 31st, 2017 were identified (n = 85,808 THA patients). Autocorrelation fit significance was determined through Box-Ljung lack of fit tests. Time series stationarity was evaluated using augmented Dickey-Fuller tests. After adjusting non-stationary time series for seasonality-dependent changes, 2-year and 10-year operative times were predicted using Autoregressive integrated moving average forecasting models.

RESULTS

Our models indicate that operative time will continue to remain stable. Specifically, operative time for ASA Class 2 is projected to fall within 1 min of the previously calculated weighted mean. Additionally, ASA Class 3 projections fall within 3 min of this value.

CONCLUSION

Operative time will remain within 3 min of the most recently reported mean up to the year 2027. Therefore, our findings do not support lowering physician compensation based on this metric. Future analyses should evaluate if operative times adjust over in light of changing patient demographics and alternative reimbursement models.

Investigating the International Normalized Ratio Thresholds for Complication in Shoulder Arthroplasty

BACKGROUND

In patients on warfarin anticoagulation therapy, elective shoulder arthroplasty surgeons must carefully balance bleeding and embolic risks. Currently, an international normalized ratio (INR) threshold of 1.5 is supported in the setting of elective surgery. However, no previous study has investigated the optimal preoperative INR target specifically in shoulder arthroplasty. The purpose of this study was to evaluate the association of preoperative INR with rates of transfusion, complication, and readmission/revision surgery in shoulder arthroplasty.

METHODS

Patients who underwent elective shoulder arthroplasty were identified in a national database. The primary outcome of interest was the risk for all-cause complication at 30 days postoperatively. Major and minor complication, revision surgery, and readmission rates were also investigated.

RESULTS

From 2006 to 2016, 1,014 procedures were identified who had undergone elective shoulder arthroplasty with a perioperative INR lab result within 24 hours of surgery. In our cohort, 550 patients (54.2%) were women, with an average age of 71.0 ± 9.8 years. After controlling for confounders, patients with a preoperative INR > 1.5 were 18.9 times as likely to have a major complication as those with a preoperative INR ≤ 1.0 (P = 0.003). Patients with an INR of 1.25 < INR ≤ 1.5 did not have a statistically significant risk of minor or major complication in comparison with those with an INR ≤ 1.0 (P = 0.23, P = 0.67).

DISCUSSION

Although recent hip and knee arthroplasty literature has found that an INR < 1.25 may be an optimal preoperative INR goal, our results did not find an increased risk for bleeding and complication with an INR ≤ 1.5 for shoulder arthroplasty. These results support current guidelines recommending a preoperative INR ≤ 1.5 for shoulder arthroplasty.

Patient-Related Risk Factors for Unplanned 30-Day Hospital Readmission Following Primary and Revision Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

Total knee arthroplasty (TKA) is a highly effective procedure for advanced osteoarthritis of the knee. Thirty-day hospital readmission is an adverse outcome related to complications, which can be mitigated by identifying associated risk factors. We aimed to identify patient-related characteristics associated with unplanned 30-day readmission following TKA, and to determine the effect size of the association between these risk factors and unplanned 30-day readmission. We searched MEDLINE and EMBASE from inception to 8 September 2020 for English language articles. Reference lists of included articles were searched for additional literature. Patients of interest were TKA recipients (primary and revision) compared for 30-day readmission to any institution, due to any cause, based on patient risk factors; case series were excluded. Two reviewers independently extracted data and carried out critical appraisal. In-hospital complications during the index admission were the strongest risk factors for 30-day readmission in both primary and revision TKA patients, suggesting discharge planning to include closer post-discharge monitoring to prevent avoidable readmission may be warranted. Further research could determine whether closer monitoring post-discharge would prevent unplanned but avoidable readmissions. Increased comorbidity burden correlated with increased risk, as did specific comorbidities. Body mass index was not strongly correlated with readmission risk. Demographic risk factors included low socioeconomic status, but the impact of age on readmission risk was less clear. These risk factors can also be included in predictive models for 30-day readmission in TKA patients to identify high-risk patients as part of risk reduction programs.

K-Means Clustering to Elucidate Vulnerable Subpopulations Among Medicare Patients Undergoing Total Joint Arthroplasty

BACKGROUND

The role of preoperative laboratory values for risk stratification following joint arthroplasty is currently ambiguous. In order to improve upon existing risk stratification within joint arthroplasty, this study sought to define novel phenotypes of total hip or total knee arthroplasty patients based entirely on preoperative laboratory measures. These phenotypes ("clusters") were compared to elucidate statistically and clinically significant differences in outcomes.

METHODS

A total of 134,252 patients were gathered from the National Surgical Quality Improvement Program database between 2005 and 2015. "K-means" with 3 clusters was applied using 9 preoperative laboratory values: sodium, blood urea nitrogen (BUN), creatinine, albumin, bilirubin, white blood cell count, hematocrit, platelet count, and international normalized ratio of prothrombin values (INR). Outcome measures included 30-day readmissions, severe adverse events, and discharge to nonhome.

RESULTS

Cluster 2 was characterized by elevated preoperative BUN, creatinine, and INR and demonstrated almost twice the rate of adverse events (3.52% vs 2.20% and 2.22%), 30-day readmissions (6.39% vs 3.31% and 3.71%), and discharge to nonhome (47.97% vs 30.50% and 35.85%). Cluster 3 was characterized by a slightly higher risk of discharge to nonhome than cluster 1 and was overwhelmingly female (79.5% female, 35.8% discharge to nonhome). Cluster 1 represents the lowest-risk subgroup, experiencing the lowest rates of readmissions, adverse events, and discharge to nonhome.

CONCLUSION

Preoperative laboratory values, namely BUN, creatinine, and INR, are useful in identifying patients at risk of adverse outcomes. This analysis supports the existing surgical literature pushing for preoperative hydration as a targeted intervention to expedite recovery.

Tranexamic Acid Combined with Compression Bandage Following Total Knee Arthroplasty Promotes Blood Coagulation: A Retrospective Analysis

Objective

This paper included a retrospective review of the effect of tranexamic acid (TXA) combined with pressure bandaging on hemostasis of patients who received a unilateral total knee arthroplasty (TKA) from 2017 to 2019.

Methods

A total of 197 patients undergoing TKA were chosen to be classified into 2 groups, the compression bandage control group and compression bandage combined with TXA observation group. The patients received blood routine examination when they were in the 1st, 3rd, and 6th days of before and postoperation. Some parameters, such as hemoglobin (Hb), C-reactive protein (CRP), D-dimer value, fibrinogen, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), international normalized ratio (INR), and erythrocyte sedimentation rate (ESR), were also investigated.

Results

In our research, the mean age was 66.54 ± 7.95 years. No difference was found in patient sex (P = 0.876) and age (P = 0.749) between groups. No differences were found in the levels of Hb, fibrinogen, TT, and INR between the 2 groups at each period (P > 0.05). The difference of PT was significantly different on the 1st day (P = 0.011), 3rd day (P = 0.010), and 6th day (P = 0.004) after surgery. Besides, the changes in APTT in observation group were clearly higher compared with the control group on the 3rd day (P = 0.001) and 6th day (P = 0.001). On the 3rd and 6th days after operation, the CRP level of the two groups increased continuously, and the CRP level was significantly higher in the observation group in comparison with the control group (P = 0.008, P = 0.010). On 1st and 3rd days after surgery, compared to the control group, the D-dimer level of patients in the observation group was distinctly fewer (P = 0.001, P = 0.027).

Conclusion

TXA combined with compression bandage is a potential option for the reduction of bleeding after TKA.

Have Total Hip Arthroplasty Operative Times Changed Over the Past Decade? An Analysis of 157,574 Procedures

BACKGROUND

With the recent reevaluation of surgeon reimbursement for total hip arthroplasty (THA) by the Centers for Medicare and Medicaid Services, there is increasing need for information regarding trends in operative time. While single-institutional analyses exist, there is a lack of large-scale, nationally representative, multi-institutional data. Therefore, the purpose of our study is to (1) evaluate past/present operative time trends for THA and (2) investigate factors influencing operative times from a 10-year, large multi-institutional database.

METHODS

All primary THAs conducted between 2008 and 2018 were queried using Current Procedural Terminology code 27130 from the American College of Surgeons-National Surgical Quality Improvement Program database, yielding 157,574 patients. Operative time, demographics, and comorbidity data were collected and analyzed. Multivariable linear models were created, and trend analyses were used where appropriate.

RESULTS

Median operative time was 87 minutes. Operative time was stable across included study years, with all calculated values within 5 minutes of the median (range, 86-92 minutes). Operative time was statistically stable over the last 3 years (P = .121). Age, body mass index, resident involvement, modified Charlson comorbidity index, and preoperative laboratory values influenced operative time (P < .001). Length of stay, readmission, superficial wound infection, and sepsis decreased over the study period. Nonelective procedures were statistically longer than elective (P < .0001).

CONCLUSION

While numerous factors influence the duration of THA, this study found that THA operative time has remained stable in recent years. Therefore, revaluation for THA based on intraservice time is not supported. Future analyses should continue to analyze factors that influence operative time in order to ensure patient safety and maintain positive outcomes.

Revisiting the International Normalized Ratio Threshold for Bleeding Risk and Mortality in Primary Total Hip Arthroplasty: A National Surgical Quality Improvement Program Analysis of 17,567 Patients

BACKGROUND

Efforts to identify preoperative risk factors for primary total hip arthroplasty have amplified with its increasing incidence. The international normalized ratio (INR) is 1 measure that may influence postoperative outcomes. This study of a national database assessed whether there exists an association between preoperative INR and postoperative bleeding and mortality among patients who underwent primary total hip arthroplasty.

METHODS

We retrospectively analyzed 17,567 adult patients who underwent primary total hip arthroplasty in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) between 2005 and 2016. Patients were stratified by preoperative INR into 4 groups: INR <1.0, 1.0 to <1.25, 1.25 to <1.5, and ≥1.5. Bleeding necessitating transfusion was the primary outcome, and secondary outcomes included mortality, infection, and readmission. Multivariable logistic regressions controlled for baseline differences.

RESULTS

Among the patients who underwent total hip arthroplasty, 20.5% had INR <1.0, 73.6% had INR 1.0 to <1.25, 4.2% had INR 1.25 to <1.5, and 1.8% had INR ≥1.5. Mortality increased incrementally from 0.3% for INR <1.0 to 4.9% for INR ≥1.5 (p < 0.001), and bleeding risk increased from 13.2% for INR <1.0 to 29.3% for INR ≥1.5 (p < 0.001). After adjustment, bleeding risk was increased for INR 1.25 to <1.5 (odds ratio [OR], 1.55 [95% confidence interval (CI), 1.26 to 1.92]) and INR ≥1.5 (OR, 1.55 [95% CI, 1.15 to 2.08]) compared with INR <1.0. The only group associated with increased mortality was INR ≥1.5 (OR, 2.69 [95% CI, 1.07 to 6.76]). The length of stay significantly increased with increasing INR, from 3.6 to 6.3 days (p < 0.001).

CONCLUSIONS

This study found a significant, independent effect between increased preoperative INR and increased bleeding and mortality. Bleeding risk becomes evident at INR ≥1.25, and those patients with INR ≥1.5 are at significantly increased risk of mortality.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Changing Patterns of Anticoagulation After Total Hip Arthroplasty in the United States: Frequency of Deep Vein Thrombosis, Pulmonary Embolism, and Complications With Rivaroxaban and Warfarin

BACKGROUND

This study evaluated the trends in anticoagulation use after total hip arthroplasty (THA), and the effectiveness and safety of rivaroxaban compared to warfarin.

METHODS

This retrospective database analysis used healthcare claims from the Truven Health MarketScan database (2010-2015). Patients undergoing elective THA were followed for use of anticoagulants after surgery. Logistic regression models were used to compare differences in deep vein thrombosis (DVT), pulmonary embolism (PE), and adverse events, within 90 days after THA, among warfarin and rivaroxaban users. Inverse probability treatment weighting was used to account for selection bias.

RESULTS

There were 12,876 users of warfarin and 10,892 users of rivaroxaban in commercially insured (CI) patients, and 7416 warfarin users and 4739 rivaroxaban users in Medicare supplement (MS) patients. Warfarin use decreased over time in both insurance cohorts, whereas rivaroxaban use increased from 2011 to 2015. Warfarin users were significantly more likely to experience both DVT (CI: odds ratio [OR] 2.63, 95% confidence interval 1.97-3.50; MS: OR 1.78, 95% confidence interval 1.38-2.29) and PE (CI: OR 2.60, 95% confidence interval 2.04-3.31; MS: OR 2.09, 95% confidence interval 1.66-2.65). There was no significant difference in rates of bleeding between the 2 agents, but warfarin users had higher odds of periprosthetic joint infection in both cohorts (CI: OR 1.57, 95% confidence interval 1.16-2.13; MS: OR 1.79, 95% confidence interval 1.14-2.81).

CONCLUSION

There has been an increase in prophylaxis with rivaroxaban, and a decrease in warfarin use after elective THA over 4 years. Warfarin users were more likely to experience DVT and PE than rivaroxaban, and bleeding risks were similar.