Final Study Report of Andexanet Alfa for Major Bleeding With Factor Xa Inhibitors.

BACKGROUND: Andexanet alfa is a modified recombinant inactive factor Xa (FXa) designed to reverse FXa inhibitors. ANNEXA-4 (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors) was a multicenter, prospective, phase-3b/4, single-group cohort study that evaluated andexanet alfa in patients with acute major bleeding. The results of the final analyses are presented. METHODS: Patients with acute major bleeding within 18 hours of FXa inhibitor administration were enrolled. Co-primary end points were anti-FXa activity change from baseline during andexanet alfa treatment and excellent or good hemostatic efficacy, defined by a scale used in previous reversal studies, at 12 hours. The efficacy population included patients with baseline anti-FXa activity levels above predefined thresholds (≥75 ng/mL for apixaban and rivaroxaban, ≥40 ng/mL for edoxaban, and ≥0.25 IU/mL for enoxaparin; reported in the same units used for calibrators) who were adjudicated as meeting major bleeding criteria (modified International Society on Thrombosis and Haemostasis definition). The safety population included all patients. Major bleeding criteria, hemostatic efficacy, thrombotic events (stratified by occurring before or after restart of either prophylactic [ie, a lower dose, for prevention rather than treatment] or full-dose oral anticoagulation), and deaths were assessed by an independent adjudication committee. Median endogenous thrombin potential at baseline and across the follow-up period was a secondary outcome. RESULTS: There were 479 patients enrolled (mean age, 78 years; 54% male; 86% White); 81% were anticoagulated for atrial fibrillation, and the median time was 11.4 hours since last dose, with 245 (51%) on apixaban, 176 (37%) on rivaroxaban, 36 (8%) on edoxaban, and 22 (5%) on enoxaparin. Bleeding was predominantly intracranial (n=331 [69%]) or gastrointestinal (n=109 [23%]). In evaluable apixaban patients (n=172), median anti-FXa activity decreased from 146.9 ng/mL to 10.0 ng/mL (reduction, 93% [95% CI, 94-93]); in rivaroxaban patients (n=132), it decreased from 214.6 ng/mL to 10.8 ng/mL (94% [95% CI, 95-93]); in edoxaban patients (n=28), it decreased from 121.1 ng/mL to 24.4 ng/mL (71% [95% CI, 82-65); and in enoxaparin patients (n=17), it decreased from 0.48 IU/mL to 0.11 IU/mL (75% [95% CI, 79-67]). Excellent or good hemostasis occurred in 274 of 342 evaluable patients (80% [95% CI, 75-84]). In the safety population, thrombotic events occurred in 50 (10%) patients; in 16 patients, these occurred during treatment with prophylactic anticoagulation that began after the bleeding event. No thrombotic episodes occurred after oral anticoagulation restart. Specific to certain populations, reduction of anti-FXa activity from baseline to nadir significantly predicted hemostatic efficacy in patients with intracranial hemorrhage (area under the receiver operating characteristic curve, 0.62 [95% CI, 0.54-0.70]) and correlated with lower mortality in patients <75 years of age (adjusted P=0.022; unadjusted P=0.003). Median endogenous thrombin potential was within the normal range by the end of andexanet alfa bolus through 24 hours for all FXa inhibitors. CONCLUSIONS: In patients with major bleeding associated with the use of FXa inhibitors, treatment with andexanet alfa reduced anti-FXa activity and was associated with good or excellent hemostatic efficacy in 80% of patients. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02329327.

Surgeon-nurse anesthetist collaboration advanced surgery between 1889 and 1950.

To meet the need for qualified anesthetists, American surgeons recruited nurses to practice anesthesia during the Civil War and in the latter half of the 19th century. The success of this decision led them to collaborate with nurses more formally at the Mayo Clinic in Minnesota. During the 1890s, Alice Magaw refined the safe administration of ether. Florence Henderson continued her work improving the safety of ether administration during the first decade of the 20th century. Safe anesthesia enabled the Mayo surgeons to turn the St. Mary's Hospital into a surgical powerhouse. The prominent surgeon George Crile collaborated with Agatha Hodgins at the Lakeside Hospital in Cleveland to introduce nitrous oxide/oxygen anesthesia. Nitrous oxide/oxygen caused less cardiovascular depression than ether and thus saved the lives of countless trauma victims during World War I. Crile devised "anoci-association," an outgrowth of nitrous oxide/oxygen anesthesia. Hodgins' use of anoci-association made Crile's thyroid operations safer. Pioneering East Coast surgeons followed the lead of the surgeons at Mayo. William Halsted worked closely with Margaret Boise, and Harvey Cushing worked closely with Gertrude Gerard. As medicine became more complex, collaboration between surgeons and nurse anesthetists became routine and necessary. Teams of surgeons and nurse anesthetists advanced thoracic, cardiovascular, and pediatric surgery. The team of Evarts Graham and Helen Lamb performed the world's first pneumonectomy. Surgeon-nurse anesthetist collaboration seems to have been a uniquely American phenomenon. This collaboration facilitated both the "Golden Age of Surgery" and the profession we know today as nurse anesthesia.

Agreement between 30-day and 90-day modified Rankin Scale score and utility-weighted modified Rankin Scale score in acute intracerebral hemorrhage: An analysis of ATACH-2 trial data.

The relationship between 30- and 90-day modified Rankin Scale (mRS) scores in intracerebral hemorrhage (ICH) patients was evaluated. This post hoc cohort analysis of the ATACH-2 trial included patients with acute ICH who were alive at 30 days and who had mRS scores reported at 30 and 90 days. The mRS score was then converted to a utility (EuroQol-5 Dimension-3 Level [EQ-5D-3L])-weighted mRS score. After adjustment of 30-day mRS score for key covariates using multivariable ordinal regression, the relationship between 30-day and observed 90-day functional outcome was assessed via absolute difference in the utility-weighted version. Of the 1000 trial subjects, 898 met inclusion criteria. This low-moderate severity ICH cohort had a median baseline GCS score of 15 and median hematoma volume of 9.7 mL. Observed 30-day mRS had the largest association with observed 90-day values (χ2 = 302.9, p < 0.0001). Patients generally either maintained the same mRS scores between 30 and 90 days (48 %) or experienced a 1-point (32 %) or 2-point (10 %) improvement by 90 days. The mean ± standard deviation (SD) EQ-5D-3L at 90 days was 0.67 ± 0.26. Following adjustment, the mean absolute difference between predicted and observed utility-weighted 90-day mRS scores was 0.006 ± 0.13 points and less than the estimated minimal clinically important difference of 0.13 points. The difference in average utility-weighted mRS scores at 30 and 90 days was not clinically relevant, suggesting 30-day score may be a reasonable proxy for 90-day values in patients with ICH when 90-day values are not available.

Using 30-day modified rankin scale score to predict 90-day score in patients with intracranial hemorrhage: Derivation and validation of prediction model.

Whether 30-day modified Rankin Scale (mRS) scores can predict 90-day scores is unclear. This study derived and validated a model to predict ordinal 90-day mRS score in an intracerebral hemorrhage (ICH) population using 30-day mRS values and routinely available baseline variables. Adults enrolled in the Antihypertensive Treatment of Acute Cerebral Hemorrhage-2 (ATACH-2) trial between May 2011 and September 2015 with acute ICH, who were alive at 30 days and had mRS scores reported at both 30 and 90 days were included in this post-hoc analysis. A proportional odds regression model for predicting ordinal 90-day mRS scores was developed and internally validated using bootstrapping. Variables in the model included: mRS score at 30 days, age (years), hematoma volume (cm3), hematoma location (deep [basal ganglia, thalamus], lobar, or infratentorial), presence of intraventricular hemorrhage (IVH), baseline Glasgow Coma Scale (GCS) score, and National Institutes of Health Stroke Scale (NIHSS) score at randomization. We assessed model fit, calibration, discrimination, and agreement (ordinal, dichotomized functional independence), and EuroQol-5D ([EQ-5D] utility weighted) between predicted and observed 90-day mRS. A total of 898/1000 participants were included. Following bootstrap internal validation, our model (calibration slope = 0.967) had an optimism-corrected c-index of 0.884 (95% CI = 0.873-0.896) and R2 = 0.712 for 90-day mRS score. The weighted ĸ for agreement between observed and predicted ordinal 90-day mRS score was 0.811 (95% CI = 0.787-0.834). Agreement between observed and predicted functional independence (mRS score of 0-2) at 90 days was 74.3% (95% CI = 69.9-78.7%). The mean ± SD absolute difference between predicted and observed EQ-5D-weighted mRS score was negligible (0.005 ± 0.145). This tool allows practitioners and researchers to utilize clinically available information along with the mRS score 30 days after ICH to reliably predict the mRS score at 90 days.

Design and rationale for REVERXaL: A real-world study of patients with factor Xa inhibitor-associated major bleeds.

BACKGROUND: The prevalence of anticoagulation treatment is increasing as an aging global population faces a high burden of cardiovascular comorbidities. Direct oral anticoagulants, including factor Xa inhibitors (FXai), are replacing vitamin K antagonists as the most commonly prescribed treatment for reducing risk of thrombotic events. While the risk of FXai-associated spontaneous bleeds is established, less is understood about their management and the effect of treatment on clinical and patient-reported outcomes. The primary objectives of the REVERXaL study are to describe patient characteristics, health care interventions during the acute-care phase, in-hospital outcomes, and associations between timing of reversal/replacement agent administration and in-hospital outcomes. Secondary/exploratory objectives focus on clinical assessments and patient-reported outcome measures (PROMs) at 30 and 90 days. METHODS: REVERXaL is a multinational, observational study of hospitalized patients with FXai-associated major bleeds in Germany, Japan, the United Kingdom, and the United States. The study includes 2 cohorts of approximately 2000 patients each. Cohort A is a historic cohort for whom medical chart data will be collected from hospitalization to discharge for patients admitted for major bleeds during FXai use within 2 years prior to enrollment of Cohort B. Cohort B will prospectively enroll patients administered any reversal/replacement agent during hospitalization to manage FXai-associated major bleeds and will include the collection of clinical outcomes and PROMs data over 3 months. CONCLUSIONS: REVERXaL will generate insights on patient characteristics, treatment approaches, and associated outcomes in patients hospitalized with FXai-associated major bleeds. These data may inform clinical practice and streamline treatment pathways in this population. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; unique identifier: NCT06147830.

Derivation and validation of a composite scoring system (SAVED2) for prediction of unfavorable modified Rankin scale score following intracerebral hemorrhage.

Objective: To develop a composite score for predicting functional outcome post-intracerebral hemorrhage (ICeH) using proxy measures that can be assessed retrospectively. Methods: Data from the observational ERICH study were used to derive a composite score (SAVED2) to predict an unfavorable 90-day modified Rankin scale (mRS) score. Independent predictors of unfavorable mRS were identified via multivariable logistic regression and assigned score weights based on effect size. Area under the curve (AUC) was used to measure the score's discriminative ability. External validation was performed in the randomized ATACH-2 trial. Results: There were 2,449 patients from ERICH with valid mRS data who survived to hospital discharge. Predictors associated with unfavorable 90-day mRS score and their corresponding point values were: age ≥70 years (odds ratio [OR], 3.8; 1-point); prior stroke (OR, 2.8; 1-point); need for ventilation (OR, 2.7; 1-point); extended hospital stay (OR, 2.7; 1-point); and non-home discharge location (OR, 5.3; 2-points). Incidence of unfavorable 90-day mRS increased with higher SAVED2 scores (P < 0.001); AUC in ERICH was 0.82 (95% CI, 0.80-0.84). External validation in ATACH-2 (n = 904) found an AUC of 0.74 (95% CI, 0.70-0.77). Conclusions: Using data collected at hospital discharge, the SAVED2 score predicted unfavorable mRS in patients with ICeH.

Definition of factor Xa inhibitor-related, life-threatening gastrointestinal bleeding and guidance on when to use reversal therapy: A Delphi panel.

Objective: To define and contextualize life-threatening gastrointestinal (GI) bleeding in the setting of factor Xa (FXa) inhibitor therapy and to derive a consensus-based, clinically oriented approach to the administration of FXa inhibitor reversal therapy. Methods: We convened an expert panel of clinicians representing specialties in emergency medicine, gastroenterology, vascular medicine, and trauma surgery. Consensus was reached among the clinician panelists using the Delphi technique, which consisted of 2 survey questionnaires followed by virtual, real-time consensus-building exercises. Results: Hypovolemia and hemodynamic instability were considered the most important clinical signs of FXa inhibitor-related, life-threatening GI bleeds. Clinician panelists agreed that potentially life-threatening GI bleeding should be determined on the basis of hemodynamic instability, signs of shock, individual patient characteristics, and clinical judgment. Last, the panel agreed that all patients with life-threatening, FXa inhibitor-associated GI bleeding should be considered for FXa inhibitor reversal therapy; the decision to reverse FXa inhibition should be individualized, weighing the risks and benefits of reversal; and when reversal is elected, therapy should be administered within 1 h after initial emergency department evaluation, when possible. Conclusions: Consensus-based definitions of life-threatening GI bleeding and approaches to FXa inhibitor reversal centered on hemodynamic instability, signs of shock, individual patient characteristics, and clinical judgment. The results from this Delphi panel may inform clinical decision-making for the treatment of patients experiencing GI bleeding associated with FXa inhibitor use in the emergency department setting.

Lower mortality with andexanet alfa vs 4-factor prothrombin complex concentrate for factor Xa inhibitor-related major bleeding in a U.S. hospital-based observational study.

Background: Well-designed studies with sufficient sample size comparing andexanet alfa vs 4-factor prothrombin complex concentrate (4F-PCC) in routine clinical practice to evaluate clinical outcomes are limited. Objectives: To compare in-hospital mortality in patients hospitalized with rivaroxaban- or apixaban-related major bleeding who were treated with andexanet alfa or 4F-PCC. Methods: An observational cohort study (ClinicalTrials.gov identifier: NCT05548777) was conducted using electronic health records between May 2018 and September 2022 from 354 U.S. hospitals. Inclusion criteria were age ≥18 years, inpatient admission with diagnosis code D68.32 (bleeding due to extrinsic anticoagulation), a record of use of the factor Xa inhibitors rivaroxaban or apixaban, andexanet alfa or 4F-PCC treatment during index hospitalization, and a documented discharge disposition. Multivariable logistic regression on in-hospital mortality with andexanet alfa vs 4F-PCC was performed. The robustness of the results was assessed via a supportive propensity score-weighted logistic regression. Results: The analysis included 4395 patients (andexanet alfa, n = 2122; 4F-PCC, n = 2273). There were 1328 patients with intracranial hemorrhage (ICH), 2567 with gastrointestinal (GI) bleeds, and 500 with critical compartment or other bleed types. In the multivariable analysis, odds of in-hospital mortality were 50% lower for andexanet alfa vs 4F-PCC (odds ratio [OR], 0.50; 95% CI, 0.39-0.65; P < .01) and were consistent for both ICH (OR, 0.55; [0.39-0.76]; P < .01) and GI bleeds (OR, 0.49 [0.29-0.81]; P = .01). Similar results were obtained from the supporting propensity score-weighted logistic regression analyses. Conclusion: In this large observational study, treatment with andexanet alfa in patients hospitalized with rivaroxaban- or apixaban-related major bleeds was associated with 50% lower odds of in-hospital mortality than 4F-PCC. The magnitude of the risk reduction was similar in ICH and GI bleeds.

Pre-diabetes, diabetes and predictors of incident angina among older women and men in the Cardiovascular Health Study.

Diabetes mellitus and angina pectoris are important conditions in older persons. The utility of pre-diabetes mellitus, diabetes mellitus and other risk factors as predictors of incident angina pectoris among older adults has not been characterized. We examined incident angina pectoris rates by sex and diabetes mellitus status in 4511 adults aged ⩾65 years without coronary heart disease at baseline from the Cardiovascular Health Study. Cox regression examined predictors of incident angina pectoris, including pre-diabetes mellitus or diabetes mellitus adjusted for sociodemographic characteristics and other risk factors, over 12.2 ± 6.9 years of follow-up. Overall, 39.1% of participants had pre-diabetes mellitus, 14.0% had diabetes mellitus and 532 (11.8%) had incident angina pectoris. Incident angina pectoris rates per 1000 person-years in those with neither condition, pre-diabetes mellitus, and diabetes mellitus were 7.9, 9.0 and 12.3 in women and 10.3, 11.2 and 14.5 in men, respectively. Pre-diabetes mellitus and diabetes mellitus were not independently associated with incident AP; however, key predictors of AP were male sex, low-density lipoprotein-cholesterol, triglycerides, systolic blood pressure, antihypertensive medication and difficulty performing at least one instrumental activity of daily living (all p < 0.05 to p < 0.01). In our cohort of older adult participants, while the incidence of AP is greater in those with diabetes mellitus, neither diabetes mellitus nor pre-diabetes mellitus independently predicted incident angina pectoris.

Revascularization Rates and Associated Costs in Patients With Stable Ischemic Heart Disease Initiating Ranolazine Versus Traditional Antianginals as Add-on Therapy.

To assess the frequency and costs of revascularization procedures in patients with stable ischemic heart disease (SIHD) initiating ranolazine versus traditional antianginals. Adults (≥18 years) with a diagnosis of SIHD who initiated ranolazine or a traditional antianginal (beta-blocker [BB], calcium channel blocker [CCB], or long-acting nitrate [LAN]) as second or third line therapy between 2008 and 2016, were selected from the IBM MarketScan Databases. Inverse probability weighting based on propensity score was employed to balance the ranolazine and traditional antianginals cohorts on patient clinical characteristics. Outcomes assessed were frequency and total cost of revascularization procedures over a 12-month follow-up. A total of 108,741 patients with SIHD were included. Of these, 18% initiated treatment with ranolazine, 21% received BBs, 24% received CCBs, and 37% were treated with LANs. Revascularization rates were significantly lower in ranolazine patients (11%) than in BB (16%) and LAN (14%) patients (both p <0.001), and more comparable to CCB patients (10%; p = 0.007). Compared with BB and LAN, those in the ranolazine cohort were less likely to have a revascularization procedure during hospitalization and had a shorter length of stay if hospitalized (all p <0.001). The mean healthcare costs associated with revascularization were lower in ranolazine patients ($2,933) than in BB ($4,465) and LAN ($3,609) patients (p <0.001), but similar to CCB patients ($2,753; p = 0.29). In conclusion, ranolazine treatment in patients with SIHD was associated with fewer revascularization procedures and lower associated healthcare costs compared with patients initiating BB or LAN, and comparable to patients initiating CCBs.

Surface plasmon resonance based assay for the detection and characterization of promiscuous inhibitors.

Promiscuous binders achieve enzyme inhibition using a nonspecific aggregation-type binding mechanism to proteins. These compounds are a source of false-positive hits in biochemical inhibition assays and should be removed from screening hit lists because they are not good candidates to initiate medicinal chemistry programs. We introduce a robust approach to identify these molecules early in the lead generation process using real time surface plasmon resonance based biosensors to observe the behavior of the binding interactions between promiscuous compounds and proteins. Furthermore, the time resolution of the assay reveals a number of distinct mechanisms that promiscuous compounds employ to inhibit enzyme function and indicate that the type of mechanism can vary depending on the protein target. A classification scheme for these compounds is presented that can be used to rapidly characterize the hits from high-throughput screens and eliminate compounds with a nonspecific mechanism of inhibition.

Angina in Coronary Artery Disease Patients With and Without Diabetes: US National Health and Nutrition Examination Survey 2001-2010.

BACKGROUND: Angina pectoris (AP) is common in coronary artery disease (CAD), but whether those with diabetes mellitus (DM) experience AP as often as those without DM is unclear. HYPOTHESIS: AP prevalence is similar in those with vs without DM in a community sample with CAD. METHODS: In adults with CAD in the US NHANES 2001-2010, AP was determined by self-report and Rose questionnaire and compared by DM status. Physical functioning and medication use were also evaluated. RESULTS: Of 1957 adults with CAD, 619 (28.2%) had DM. Prevalence of AP was similar in those with vs without DM (48.9% vs 46.3%; P = 0.38). There was a trend toward more severe AP in those with glycated hemoglobin ≥7% (50.4%) vs <7% (27.1%; P = 0.09). Adjusted logistic regression showed a similar odds of AP (1.06, 95% CI: 0.84-1.33) in those with vs without DM, although among DM, a 2-fold greater odds of AP in women vs men. Physical functioning was worse in those with vs without AP overall (score of 25.9 vs 24.3; P < 0.001) and further diminished within those with comorbid DM (26.7 vs 24.0; P < 0.001). Among those with AP, those with vs without DM were more likely on ß-blockers, statins, angiotensin-converting enzyme inhibitors, and antiplatelet therapy. CONCLUSIONS: AP in CAD patients is similar among those with vs without DM, despite greater use of evidence-based therapies in DM patients. Greater physical limitations exist in those with vs without AP, and further diminish with comorbid DM.

Comparative Effectiveness of Ranolazine Versus Traditional Therapies in Chronic Stable Angina Pectoris and Concomitant Diabetes Mellitus and Impact on Health Care Resource Utilization and Cardiac Interventions.

Comparative studies evaluating traditional versus newer antianginal (AA) medications in chronic stable angina pectoris (CSA) on cardiovascular (CV) outcomes and utilization are limited, particularly in patients with diabetes mellitus (DM). Claims data (2008 to 2012) were analyzed using a commercial database. Patients with CSA receiving a ß blocker (BB), calcium channel blocker (CCB), long-acting nitrate (LAN), or ranolazine were identified and followed for 12 months after a change in AA therapy. Patients on traditional AA medications were required to have concurrent sublingual nitroglycerin. Therapy change was defined as adding or switching to another traditional AA medication or ranolazine to identify patients whose angina was inadequately controlled with previous therapy. Four groups were identified (BB, CCB, LAN, or ranolazine users) and matched on relevant characteristics. A DM subset was identified. Logistic regression compared revascularization at 30, 60, 90, 180, and 360 days. Negative binomial regression compared all-cause, CV-, and DM-related (in the DM cohort) health care utilization. A total of 8,008 patients were identified with 2,002 patients in each matched group. Majority were men (mean age 66 years). A subset of 3,724 patients with DM (BB, n = 933; CCB, n = 940; LAN, n = 937; and ranolazine, n = 914) resulted from this cohort. Compared to ranolazine in the overall cohort, traditional AA medication exhibited greater odds for revascularization and higher rates in all-cause outpatient, emergency room visits, inpatient length of stay, and CV-related emergency room visits. In the DM cohort, ranolazine demonstrated similar benefits over traditional AA medication. In conclusion, ranolazine use in patients with inadequately controlled chronic angina is associated with less revascularization and all-cause and CV-related health care utilization compared to traditional AA medication.

A tetrodotoxin-resistant voltage-gated sodium channel from human dorsal root ganglia, hPN3/SCN10A.

Neuropathic pain may be produced, at least in part, by the increased activity of primary afferent neurons. Studies have suggested that an accumulation of voltage-gated sodium channels at the site of peripheral nerve injury is a primary precursory event for subsequent afferent hyperexcitability. In this study, a human sodium channel (hPN3, SCN10A) has been cloned from the lumbar 4/5 dorsal root ganglia (DRG). Expression of hPN3 in Xenopus oocytes showed that this clone is a functional voltage-gated sodium channel. The amino acid sequence of hPN3 is most closely related to the rat PN3/SNS sodium channels which are expressed primarily in the small neurons of rat DRGs. The homologous relationship between rPN3 and hPN3 is defined by (i) a high level of sequence identity (ii) sodium currents that are highly resistant to tetrodotoxin (TTX) (iii) similar tissue distribution profiles and (iv) orthologous chromosomal map positions. Since rPN3/SNS has been implicated in nociceptive transmission, hPN3 may prove to be a valuable target for therapeutic agents against neuropathic pain.

Influence of global region on outcomes in heart failure ß-blocker trials.

OBJECTIVES: We sought to describe the United States and the rest of the world (ROW) outcomes from the major ß-blocker heart failure (HF) trials. BACKGROUND: HF trials have demonstrated differences in outcomes by geographic region. METHODS: Randomized, double-blind, placebo-controlled studies that evaluated ß-blockers in HF patients, had a primary endpoint of mortality, and enrolled U.S. patients were included. Relative risk (RR) was calculated for patients enrolled in the United States and ROW. Meta-analysis of the combined mortality rates was performed using the Cochran-Mantel-Haenszel statistic, stratified by study. RESULTS: A total of 8,988 patients were enrolled in the MERIT-HF (Metoprolol Controlled-Release Randomized Intervention Trial in Heart Failure), COPERNICUS (Carvedilol Prospective Randomized Cumulative Survival trial), and BEST (ß-Blocker Evaluation of Survival Trial) combined; 4,198 (46.7%) were from the United States. In the U.S. cohort, the RR reduction for each ß-blocker was of smaller magnitude than in the overall cohort and no longer significant, whereas in the ROW subgroup, the mortality benefit for ß-blockade persisted. In the pooled analysis (n = 11,635), the RR of death was reduced by 23% (p < 0.001) with ß-blockade compared with placebo. In contrast, the mortality reduction associated with ß-blockade in the U.S. cohort was small and not statistically significant (RR: 0.92, 95% confidence interval [CI]: 0.82 to 1.02, p = 0.11). The survival benefit persisted in the ROW cohort (RR: 0.64, 95% CI: 0.56 to 0.72, p < 0.001). CONCLUSIONS: Among patients enrolled in the United States, ß-blockade was associated with a lower magnitude of survival benefit, whereas the ROW response was similar to the total study population. This geographic difference in treatment response may be a reflection of population differences, genetics, cultural or social differences in disease management, or low power and statistical chance.