Incidence and Time Course of Symptomatic Thromboembolic Outcomes After Lower Extremity Arthroscopic Surgery, Ankle Fracture Surgery, and Achilles Tendon Repair.

BACKGROUND: The incidence and time course of acute venous thromboembolism (VTE) after ambulatory surgery for lower extremity orthopaedic conditions is not well-defined. HYPOTHESIS: The purpose of this study was to analyze the incidence, the time course, and risk factors associated with clinically diagnosed acute deep vein thrombosis or pulmonary embolism within 3 months of surgery in patients undergoing specific operations for lower extremity injuries. METHODS: Patients undergoing arthroscopic procedures of the knee, ankle fracture surgery, Achilles tendon repair, and ankle arthroscopy from January 1, 2005, to December 31, 2010, were identified in the California Ambulatory Surgery database with linkage to hospital discharge data, emergency department data, and a death registry. Outcomes were acute VTE and death within 90 days. Time courses were compared using Kaplan-Meier analysis, and risk factors were analyzed using proportional hazard modeling. RESULTS: Analysis of data from 468,699 surgeries showed that the cumulative incidence of acute VTE was significantly higher after Achilles tendon repair (0.72%, P < 0.001) than ankle fracture surgery (0.33%), knee arthroscopy procedures (range, 0.29% to 0.41%), or ankle arthroscopy (0.24%). The time course of diagnosis of VTE was similar for all arthroscopic procedures (median postoperative day for diagnosis = 9 to 10; 80% by 22 to 36 days), whereas for Achilles tendon surgery, the time course was protracted (median postoperative day for diagnosis = 29 days; 80% by 51 days). Ninety-day mortality was low (<0.06%) after all procedures except ankle fracture (0.12%). Predictors of pulmonary embolism included age older than 60 years (HR, 3.1; 95% CI; 2.0 to 4.8, versus younger than 30 years), Achilles tendon repair (HR, 3.8; 95% CI; 2.8 to 5.3), and ankle fracture surgery (Hazard Ratio [HR], 2.1; 95% Confidence Interval [CI]; 1.5 to 2.8); Asian/Pacific Islander (HR, 0.3; 95% CI; 0.1 to 0.6) and Hispanic patients (HR, 0.5; 95% CI; 0.4 to 0.7) had significantly lower risk. DISCUSSION: The incidence and time course of onset of acute VTE after lower extremity orthopaedic surgeries varies significantly depending on the surgical procedure. These findings have implications regarding the use and duration of pharmacologic thromboprophylaxis.

Left atrial appendage closure during cardiac surgery: Safe but underutilized in California.

Objective: Left atrial appendage (LAA) closure is associated with reduced rates of stroke in patients with atrial fibrillation (AF). We evaluated trends in LAA closure, the association of LAA closure with stroke/systemic embolism, and its safety profile in patients with AF who underwent cardiac surgery in California. We further tested for hospital-level variation in concomitant LAA closure. Methods: Adults who underwent coronary artery bypass grafting and/or valve surgery with preoperative AF were identified in the 2016 to 2019 Office of Statewide Health Planning and Development databases. Propensity score matching was performed to study risk-adjusted associations of LAA closure with ischemic stroke/systemic embolism. Hospital-level variation was studied using intraclass correlation coefficients. Results: Among 18,434 patients with AF who underwent coronary artery bypass grafting/valve surgery, 47.7% received LAA closure. Rates of LAA closure increased from 44.4% to 51.4% from 2016 to 2019 (P < .001). In 4652 propensity score-matched patients, LAA closure was associated with reduced incidence of stroke/systemic embolism at discharge (1.6% vs 3.1%; P < .001) and readmission with stroke/systemic embolism at 1 year (2.9% vs 4.5%; P = .004). LAA closure was not associated with acute kidney injury, pulmonary complications, blood transfusion, reoperation, or in-hospital mortality. Approximately 18% of the risk-adjusted variation in LAA use was attributed to the hospital, with median center-level rate of 44.9% (interquartile range, 29.6%-57.4%). Conclusions: LAA closure was associated with minimal surgical morbidity, and reduced short- and midterm incidence of stroke/systemic embolism. Although the use of LAA closure has increased, substantial variation exists among programs in California, suggesting the need for further standardization of care.

Linked birth cohort files for perinatal health research: California as a model for methodology and implementation.

PURPOSE: Rigorous perinatal epidemiologic research depends on population-based parental and neonatal sociodemographic and clinical data. Here we describe the creation of linked birth cohort files, an enriched data source that combines information from vital records with maternal delivery and infant hospital encounter records. METHODS: Probabilistic linkage techniques were used to link vital records (i.e., birth and fetal death certificates) from the California Department of Public Health with hospital inpatient, ambulatory surgery and emergency department encounter data for mothers and infants from the California Department of Health Care Access and Information. RESULTS: From 2012 to 2018, 95% of live birth records were successfully linked to maternal and newborn hospital records while 85% of fetal death records were linked to a maternal delivery record. Overall, 93% of postnatal hospital encounters of infants (i.e., <1 year old) were matched to a linked record. CONCLUSIONS: The linked birth cohort files is a rich resource opening many possibilities for understanding perinatal health outcomes and opportunities for linkage to longitudinal, social determinant, and environmental data. To optimally use this file for research, analysts should evaluate possible shortcomings or biases of the data sources being linked.

Regional Variation in the Use and Outcomes of Transcatheter Aortic Valve Replacement in California.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has been widely adopted for management of aortic stenosis. The purpose of this study was to examine regional access to and outcomes following TAVR in California. METHODS: Patients undergoing TAVR or isolated surgical aortic valve replacement (SAVR) from 2008 to 2019 in California were identified in the Office of Statewide Health Planning and Development database. California was divided into seven regions: Northern California, San Francisco Bay Area, Central California, Los Angeles, Inland Empire, Orange, and San Diego. Regional TAVR volumes were normalized to Medicare beneficiaries or isolated SAVR volume. Outcomes included risk-adjusted 30-day mortality and major adverse cardiovascular and cerebral events (MACCE). Trends were studied using non-parametric tests, and regional outcomes using logistic regression. RESULTS: TAVR volume increased annually since 2011, with 7148 cases performed in California in 2019. After normalization, variation in utilization of TAVR was evident, with the least performed in Central California. TAVR to SAVR ratios in 2019 were greatest in Northern California, Los Angeles, and San Diego, and least in the Inland Empire. After risk adjustment, there were no significant regional differences in 30-day mortality, but lower 30-day MACCE in the San Francisco Bay Area. CONCLUSIONS: Regional differences in TAVR utilization exist, with limited access in Central California and the Inland Empire, but risk-adjusted outcomes are similar. Efforts to reach underserved areas through existing program expansion or regional referrals may distribute transcatheter technology more equitably across California.

Use of Statewide Administrative Data to Assess Clinical Outcomes: A Retrospective Cohort Study of Therapeutic Anticoagulation for Isolated Calf Vein Thrombosis.

BACKGROUND: Single-center comparative effectiveness studies evaluating outcomes that can occur posthospitalization may become biased if outcomes diagnosed at other facilities are not ascertained. Administrative datasets that link patients' records across facilities may improve outcome ascertainment. OBJECTIVE: To determine whether use of linked administrative data significantly augments thromboembolic outcome ascertainment. RESEARCH DESIGN: Retrospective cohort study. SUBJECTS: Patients with an acute isolated calf deep vein thrombosis (DVT) diagnosed at 1 Californian center during 2010-2013. MEASURES: Proximal DVT or pulmonary embolism (PE) within 180 days. We ascertained outcomes from linked California hospitalization, emergency department, and ambulatory surgery data and compared this information to outcomes previously identified from review of the center's medical records. RESULTS: Among 384 patients with an isolated calf DVT, 333 could be linked to longitudinal administrative data records. Ten patients had a possible proximal DVT or PE (4 more clearly so) from administrative data; all were unknown from medical record review. Eleven patients with known outcomes from medical record review had no outcome from administrative data. The adjusted odds ratio of proximal DVT or PE with therapeutic anticoagulation attenuated from 0.33 [95% confidence interval (CI), 0.12-0.87] using only medical record review to 0.64 (95% CI, 0.29-1.40) using both medical record review and possible outcomes from administrative data. Restricting the outcome to diagnoses clearly involving proximal DVT or PE, the adjusted odds ratio was 0.46 (95% CI, 0.19-1.10). CONCLUSIONS: Use of linked hospital administrative data augmented detection of outcomes but imperfect linkage, nonspecific diagnoses, and documentation/coding errors introduced uncertainty regarding the accuracy of outcome ascertainment.

Female Sex and Longer Fusion Constructs Significantly Increase the Risk of Total Hip Arthroplasty Following Spinal Fusion.

BACKGROUND: Previous studies have noted the progression of arthritis due to increased forces in articular structures adjacent to a fused joint. It is unknown whether spinal fusion generates increased forces at the hip joint causing progression to arthritis leading to total hip arthroplasty (THA). We sought to determine (1) is there a relationship between spinal fusion and THA, (2) what are risk factors for subsequent THA, and (3) is there a time interval from spinal fusion to THA? METHODS: A large patient discharge dataset was utilized to evaluate all patients who underwent spinal fusion and subsequent THA in California from 2004 through 2013. Patients were categorized by age, sex, hospital type, hospital volume, and number of spinal levels fused. Multivariate analysis was performed to investigate the relationship between spinal fusion and THA. Hazard ratios were calculated for risk factors for THA after spinal fusion. Patients were excluded for previous spinal fusion or hip arthroplasty, inflammatory arthropathy, cancer, and an age of ≤40 years, a surrogate for adolescent and neuromuscular scoliosis. RESULTS: A total of 101,206 patients underwent spinal fusion; 2,803 (2.77%) subsequently underwent THA. In a bivariate analysis comparing 1 to 2 levels versus >2 levels fused, males had a 17% increased relative risk of undergoing subsequent THA (relative risk [RR] = 1.17; 95% confidence interval [CI] = 1.16 to 1.17) and female patients had a 35% increased relative risk (RR = 1.35; 95% CI = 1.34 to 1.35) when the fusion involved >2 levels. For females, the relative risk increased by 119% when >7 levels were fused compared with 1 to 7 levels (RR = 2.19; 95% CI = 2.16 to 2.21). Using multivariate random-effects analysis, significant risk factors for THA after spinal fusion included female sex (hazard ratio [HR] = 1.21; 95% CI = 1.13 to 1.31; p < 0.0001) and spinal fusion of >7 levels (HR = 1.52; 95% CI = 1.03 to 2.24; p = 0.035). CONCLUSIONS: Patients with longer spinal fusion constructs, especially female patients, had a significantly increased risk of undergoing subsequent THA. Patients should be educated regarding the potential for the progression to hip arthritis after spinal fusion and the possibility of future THA. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Selection of Higher Risk Pregnancies into Veterans Health Administration Programs: Discoveries from Linked Department of Veterans Affairs and California Birth Data.

OBJECTIVE: To describe variation in payer and outcomes in Veterans' births. DATA/SETTING: Secondary data analyses of deliveries in California, 2000-2012. STUDY DESIGN: We performed a retrospective, population-based study of all live births to Veterans (confirmed via U.S. Department of Veterans Affairs (VA) enrollment records), to identify payer and variations in outcomes among: (1) Veterans using VA coverage and (2) Veteran vs. all other births. We calculated odds ratios (aOR) adjusted for age, race, ethnicity, education, and obstetric demographics. METHODS: We anonymously linked VA administrative data for all female VA enrollees with California birth records. PRINCIPAL FINDINGS: From 2000 to 2012, we identified 17,495 births to Veterans. VA covered 8.6 percent (1,508), Medicaid 17.3 percent, and Private insurance 47.6 percent. Veterans who relied on VA health coverage had more preeclampsia (aOR 1.4, CI 1.0-1.8) and more cesarean births (aOR 1.2, CI 1.0-1.3), and, despite similar prematurity, trended toward more neonatal intensive care (NICU) admissions (aOR 1.2, CI 1.0-1.4) compared to Veterans using other (non-Medicaid) coverage. Overall, Veterans' birth outcomes (all-payer) mirrored California's birth outcomes, with the exception of excess NICU care (aOR 1.15, CI 1.1-1.2). CONCLUSIONS: VA covers a higher risk fraction of Veterans' births, justifying maternal care coordination and attention to the maternal-fetal impacts of Veterans' comorbidities.

CAABL-AF (California Study of Ablation for Atrial Fibrillation): Mortality and Stroke, 2005 to 2013.

BACKGROUND: Ablation for atrial fibrillation (AF) is superior to medical therapy for rhythm control. We compared stroke and mortality among patients undergoing ablation for AF to matched controls in a large multiethnic population. METHODS: Using discharge and surgical records from California nonfederal hospitals, we identified patients who had ablation and principal diagnosis of AF with at least 1 prior hospitalization for AF. We excluded cases with valve disease, open maze, other arrhythmias, or implantable devices. Matched controls were selected based on years of AF diagnosis, age, sex, and being alive the same number of days from the initial AF encounter to the ablation date. Clinical outcomes, including mortality, ischemic stroke, or hemorrhagic stroke, were assessed using a weighted proportional hazard model, adjusting for demographics, prior admissions with AF before the ablation, calendar year, and presence of chronic comorbidities. RESULTS: There were 4169 ablation cases and 4169 weighted-matched controls; 39% percent of the ablation group was >65 years, 72% men, 84% white; mean follow-up was up to 3.6±0.9 years. In adjusted models, ablation was associated with significantly lower mortality (per patient-years) 0.9% versus 1.9%, hazard ratio=0.59 (P<0.0001; confidence interval: 0.45-0.77); ischemic stroke (>30 days post-ablation ≤5 years), 0.37% versus 0.59%, hazard ratio=0.68 (P=0.04; confidence interval: 0.47-0.97); hemorrhagic stroke 0.11% versus 0.35%, hazard ratio=0.36 (P=0.001; confidence interval: 0.20-0.64) compared with controls. CONCLUSIONS: In this large population-based study of hospitalized patients with nonvalvular AF, ablation was associated with lower mortality, ischemic stroke, and hemorrhagic stroke compared with controls.

Implementation of transcatheter aortic valve replacement in California: Influence on aortic valve surgery.

OBJECTIVE: Transcatheter aortic valve replacement (TAVR) procedures were introduced in 2011. Initially, procedures were limited to patients who were not surgical candidates, but subsequently high-risk surgical candidates were considered for TAVR. The influence on aortic valve surgery in California is unknown. METHODS: The California Office of Statewide Health Planning and Development hospitalized patient discharge database was queried for the years 2009 through 2014. isolated surgical aortic valve and aortic valve/coronary artery bypass graft (SAVR) and TAVR procedures were identified by International Classification of Diseases-9th revision clinical modification procedure codes. Seven TAVR programs were introduced in 2011, 12 in 2012, 3 in 2013, and 6 in 2014. SAVR procedure volumes were compared from the 2 years before institution with SAVR volumes during the year(s) after institution of the TAVR program in these 28 hospitals. RESULTS: Overall, surgical volumes increased during the first, second, and third years after implementation of TAVR procedures. Among 7 hospitals with 4-year programs, surgical volumes increased to a maximum of 15.5% during the third year, then began to decrease. The hospital performing the largest number of TAVR procedures showed a marked decrease in SAVR volume by the fourth year, suggesting a shift of SAVR candidates to TAVR. Among all hospitals with 4-year programs, TAVR exceeded SAVR procedures by the fourth year. In California overall, SAVR increased during 2011 through 2013, due primarily to increasing volume of isolated SAVR procedures. Statewide, isolated SAVR increased from a yearly average of 3111 procedures during 2009-2010 to 3592 (+15.5%) in 2013, then decreased slightly in 2014. SAVR plus coronary artery bypass graft procedures decreased during the same time period. CONCLUSIONS: After implementation of TAVR, hospital SAVR volumes increased moderately, then began to decrease by the fourth year, when TAVR volume exceeded SAVR. Surgical candidates may be identified during evaluation for TAVR, resulting in increased SAVR volume. Increasing SAVR volume may also be related to improved patient and provider awareness of aortic valve disease.

Postoperative Stiffness Requiring Manipulation Under Anesthesia Is Significantly Reduced After Simultaneous Versus Staged Bilateral Total Knee Arthroplasty.

BACKGROUND: For patients with symptomatic bilateral knee arthritis, it is unknown whether the risk of developing stiffness requiring manipulation under anesthesia postoperatively is higher or lower for those undergoing simultaneous bilateral total knee arthroplasty (TKA) compared with those having staged bilateral TKA. Therefore, we undertook this study to evaluate the risk of requiring manipulation under anesthesia in staged versus simultaneous bilateral TKA as well as patients undergoing unilateral TKA. METHODS: We utilized the California Patient Discharge Database, which is linked with the California Emergency Department, Ambulatory Surgery, and master death file databases. Using a literature-based estimate of the number of patients who failed to undergo the second stage of a staged bilateral TKA, replacement cases were randomly selected from patients who had unilateral TKA and were matched on 8 clinical characteristics of the patients who had staged bilateral TKA. Hierarchical multivariate logistic regression was performed to determine the risk-adjusted odds of manipulation in patients undergoing unilateral TKA, staged bilateral TKA, and simultaneous bilateral TKA using yearly hospital TKA volume as a random effect. Adjustment was made to allow fair comparison of the outcome at 90 and 180 days of follow-up after staged compared with simultaneous bilateral TKA. RESULTS: During the time period from 2005 through 2013, the cumulative incidence of manipulation within 90 days was 2.14% for unilateral TKA (4,398 events per 205,744 patients), 2.11% for staged bilateral TKA (724 events per 34,352 patients), and 1.62% for simultaneous bilateral TKA (195 events per 12,013 patients). At 180 days of complete follow-up, the cumulative incidence of manipulation was 3.07% after unilateral TKA (6,313 events per 205,649 patients), 2.89% after staged bilateral TKAs (957 events per 33,169 patients), and 2.29% after simultaneous bilateral TKA (267 events per 11,653 patients). With multivariate analyses used to adjust for relevant risk factors, the 90-day odds ratio (OR) of undergoing manipulation after simultaneous bilateral TKA was significantly lower than that for unilateral TKA (OR = 0.70; 95% confidence interval [CI], 0.57 to 0.86) and staged bilateral TKA (OR = 0.71; 95% CI, 0.57 to 0.90). Similarly, at 180 days, the odds of undergoing manipulation were significantly lower after simultaneous bilateral TKA than after both unilateral TKA (OR = 0.71; 95% CI, 0.59 to 0.84) and staged bilateral TKA (OR = 0.76; 95% CI, 0.63 to 0.93). The frequency of manipulation was significantly associated with younger age, fewer comorbidities, black race, and the absence of obesity. CONCLUSIONS: Although the ORs were small (close to 1), simultaneous bilateral TKA had a significantly decreased rate of stiffness requiring manipulation under anesthesia at 90 days and 180 days after knee replacement compared with that after staged bilateral TKA and unilateral TKA. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

California study of Ablation (CAABL):early utilization after index hospitalization for non-valvular atrial fibrillation.

BACKGROUND: Catheter ablation (ABL) for non-valvular AF (NVAF) is recommended for symptomatic patients refractory to medical therapy and its success is related to the duration of the arrhythmia prior to intervention.Our aim was to assess the early utilization and the factors that prompted ABL in patients hospitalized for new onset NVAF. METHODS: Using de-identified administrative discharge records for hospitalizations and emergency department (ED) visits, we determined the patients who had a first-time (since 1991) health record diagnosis of AF between2005 - 2011. We linked ambulatory surgery encounters for ABL based on ICD 9 code occurring within two years of initial hospitalization. After excluding other cardiac arrhythmias, atrio-ventricular nodal ablation or pacemaker/defibrillator placement and cardiac valve disease, bivariate comparisons were made with those who did not undergo ABL. RESULTS: During the study period,3,440 of 424,592 patients (0.81%) hospitalized for new onset NVAF underwent ABL. Parameters significantly (p<0.001) associated with ABL compared tonon-ABL patientsincluded: principal diagnosis of AF (55% vs 25%), age 35-64 yrs (46.1% vs. 22.4%), male (58.9% vs. 48.2%), private insurance (46.6% vs. 21.1%), Caucasian (81.0% vs.71.6%), lower frequency of ED visit < 6 months before index AF hospitalization (10.7% vs. 15.9%), lower severityofillness at time of AF diagnosis (16.5% vs. 35.6%) anda lower prevalence ofmajor comorbidities (p< 0.001). CONCLUSIONS: Ablation has low utilization for treatment of new onset NVAF within two years of diagnosis. Earlier utilization of ABL may reduce health care burden related to NVAF and requires further evaluation.

Defining operative mortality: Impact on outcome reporting.

OBJECTIVE: Death is an important outcome of procedural interventions. The death rate, or mortality rate, is subject to variability by definition. The Society of Thoracic Surgeons Adult Cardiac Surgery Database definition of "operative" mortality originally included all in-hospital deaths and deaths occurring within 30 days of the procedure. In recent versions of the Society of Thoracic Surgeons Adult Cardiac Surgery Database, "in-hospital" has been modified to include "patients transferred to other acute care facilities," and "deaths within 30 days unless clearly unrelated to the procedure" has been changed to "deaths within 30 days regardless of cause." This study addresses the impact of these redefinitions on outcome reporting. METHODS: The California Office of Statewide Health Planning and Development hospitalized patient discharge database was queried for the year 2009, the most recent year that data files could be linked to the vital statistics death files to include all-cause mortality. Isolated coronary artery bypass grafting, isolated valve, coronary artery bypass grafting valve, and percutaneous coronary intervention procedures were identified by International Classification of Diseases, Ninth Edition, Clinical Modification procedure codes. Percutaneous coronary intervention procedures were further divided into acute coronary syndrome (percutaneous coronary intervention acute coronary syndrome) and all other percutaneous coronary intervention (percutaneous coronary intervention no acute coronary syndrome). Deaths were counted by 5 methods depending on the time and place of occurrence: (1) in-hospital or during the index hospitalization; (2) in-hospital + connected hospitalization, defined as a transfer to another acute care facility on the same day or within 24 hours of discharge; (3) in-hospital + 30 day, death during index hospitalization or within 30 days after the procedure; (4) in-hospital + connected + 30 day readmission, death during index hospitalization, transfer to acute care facility, or deaths during readmission within 30 days; and (5) in-hospital + connected + 30 day. To study the impact of these operative mortality definitions, we examined 5 different methods to track mortality and performed 2 separate analyses. The first analysis did not exclude any patients, and the second analysis excluded any patient who could not be accurately tracked after hospital discharge. RESULTS: In the first analysis with no patients excluded, a total of 17% (117/697) of surgical deaths and 31% (409/1324) of percutaneous coronary intervention deaths were counted after the original hospitalization. The highest percentage of posthospital deaths occurred after elective percutaneous coronary intervention: 45% (135/301). In surgical patients, the highest percentage of posthospital deaths occurred in coronary artery bypass grafting procedures: 20% (57/284). In the second analysis, with untrackable patients excluded, hospital deaths included 12% (161/1324) for percutaneous coronary intervention compared with 4% (30/697) for surgical procedures. CONCLUSIONS: A significant percentage of procedural deaths occur after transfer or discharge from the index hospital. This is especially evident in the percutaneous coronary intervention group. These findings illustrate the importance of the definition of "operative" mortality and the need to ensure accuracy in the reporting of data to voluntary clinical registries, such as the Society of Thoracic Surgeons Adult Cardiac Surgery Database and National Cardiovascular Data Registry.

Hospital variation in medical and surgical treatment of patent ductus arteriosus.

OBJECTIVE: This study aims to characterize population risks for diagnosis, medical treatment, and surgical ligation of patent ductus arteriosus (PDA) in very low-birth-weight infants. STUDY DESIGN: Maternal and neonatal data were collected in 40 hospitals in California during 2011 for infants with birth weight ≤ 1,500 g without any congenital malformation, with a diagnosis of PDA. Multivariable logistic regression was used to determine independent risks for PDA diagnosis and for surgical ligation. RESULTS: There were 770/1,902 (40.4%) infants diagnosed with PDA. Low birth weight, gestational age, respiratory distress syndrome, and surfactant administration were associated with PDA diagnosis. Ligation occurred in 43% of patients with birth weight ≤ 750 g, in 24% of patients weighing between 715 and 1,000 g, and in 12% of patients weighing from 1,001 to 1,500 g. Older gestational age (1 week, odds ratio 0.55, 95% confidence interval 0.48-0.63) and absence of respiratory distress syndrome (odds ratio 0.14, 95% confidence interval 0.03-0.59) were associated with lower ligation risk. The median hospital ligation rate was 14% (interquartile range 0-38%). CONCLUSION: Most patients with PDA receive treatment for closure. Practice variation may set the stage for further exploration of experimental trials.

Probabilistic Linkage of Prehospital and Outcomes Data in Out-of-hospital Cardiac Arrest.

OBJECTIVE: Lack of longitudinal patient outcome data is an important barrier in emergency medical services (EMS) research. We aimed to demonstrate the feasibility of linking prehospital data from the California EMS Information Systems (CEMSIS) database to outcomes data from the California Office of Statewide Health Planning and Development (OSHPD) database for patients with out-of-hospital cardiac arrest (OHCA). METHODS: We included patients age 18 years or older who sustained nontraumatic OHCA and were included in the 2010-2011 CEMSIS databases. The CEMSIS database is a unified EMS data collection system for California. The OSHPD database is a comprehensive data collection system for patient-level inpatient and emergency department encounters in California. OHCA patients were identified in the CEMSIS database using cardiac rhythm, procedures, medications, and provider impression. Probabilistic linkage blocks were created using in-hospital death or one of the following primary or secondary diagnoses (ICD-9-CM) in the OSHPD databases: cardiac arrest (427.5), sudden death (798), ventricular tachycardia (427.1), ventricular fibrillation (427.4), and acute myocardial infarction (410.xx). Blocking variables included incident date, gender, date of birth, age, and/or destination facility. Due to the volume of cases, match thresholds were established based on clerical record review for each block individually. Match variables included incident date, destination facility, date of birth, sex, race, and ethnicity. RESULTS: Of the 14,603 cases of OHCA we identified in CEMSIS, 91 (0.6%) duplicate records were excluded. Overall, 46% of the data used in the linkage algorithm were missing in CEMSIS. We linked 4,961/14,512 (34.2%) records. Linkage rates varied significantly by local EMS agency, ranging from 1.4 to 61.1% (OR for linkage 0.009-0.76; p < 0.0001). After excluding the local EMS agency with the outlying low linkage rate, we linked 4,934/12,596 (39.2%) records. CONCLUSION: Probabilistic linkage of CEMSIS prehospital data with OSHPD outcomes data was severely limited by the completeness of the EMS data. States and EMS agencies should aim to overcome data limitations so that more effective linkages are possible.

Risk predictors of stroke and mortality after ablation for atrial fibrillation: the California experience 2005-2009.

BACKGROUND: Ablation (ABL) is a second-line therapy for the management of atrial fibrillation (AF). Single-center studies have demonstrated the safety and efficacy of ABL; however, the low event rates render it difficult to assess predictors of major adverse events. OBJECTIVE: The purpose of this study was to determine the population-based incidence of data and risk factors for both stroke <30 days and death after AF ABL. METHODS: Patients (n = 6207) identified as having undergone AF ABL between 2005 and 2009 by the California Ambulatory Surgery Database in 97 nonfederal hospitals in California were linked to the California Patient Discharge Database and to a master death registry. Data from these patients were analyzed for primary outcomes of 30-day death and ischemic stroke. Independent risk factors for these end-points were determined. RESULTS: Mean patient age was 61.9 years, and the majority of the patients were men. Thirty-day mortality and stroke after ABL were 0.39% and 0.61%, respectively. Independent predictors of death were age ≥80 years (odds ratio [OR] 8.2, 95% confidence interval [CI] 1.5-43) and heart failure (OR 9.2, 95% CI 3.0-28). Prior stroke/transient ischemic attack/stroke was the only independent predictor for stroke (OR 6.3, 95% CI 3-13). CONCLUSION: In our large population-based study, we found higher procedure-related mortality but comparable stroke rate after AF ABL than previously reported. Age ≥80 years and heart failure was each independently associated with >8-fold increase in odds of death. The only significant predictor of stroke was prior stroke/transient ischemic attack. These findings may aid in patient selection for AF ABL.

Intraoperative conversion from off-pump to on-pump coronary artery bypass is associated with increased 30-day hospital readmission.

BACKGROUND: We evaluated the impact of intraoperative conversion from off-pump coronary artery bypass graft surgery (OPCAB) to conventional coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CCB) on rates of postoperative 30-day hospital readmissions. METHODS: Using data from the California CABG outcomes reporting program, postoperative 30-day hospital readmissions were compared among CCB, OPCAB, and intraoperative conversions from OPCAB to CCB (IOC) for isolated CABG operations. A multivariable logistic regression model with inverse propensity for OPCAB weighting was used to compute risk-adjusted readmission rates. General linear models were used to test the differences in propensity-weighted and risk-adjusted readmission rates among CCB, OPCAB, and IOC cases. RESULTS: Among 22,389 isolated CABGs, 5,125 (22.9%) were OPCAB; 595 (11.6%) OPCAB patients had intraoperative conversion from OPCAB to CCB (IOC). The patients who underwent IOC had a higher prevalence of preoperative heart failure, left main coronary artery disease, and 3 or greater diseased coronary vessels compared with OPCAB without conversion. The risk-adjusted readmission model (weighted for OPCAB propensity) showed OPCAB without conversion was not associated with any increase in readmission rates when compared with CCB (adjusted odds ratio [AOR]; 1.02, 95% confidence interval [CI], 0.963 to 1.081) but OPCAB with IOC had a significant effect on readmission (AOR, 1.258; 95% CI, 1.122 to 1.411, p<0.0001). The OPCAB with IOC was also associated with a higher proportion of readmissions due to postoperative infection (19.1% vs 11.9% of readmissions for CCB). CONCLUSIONS: Intraoperative conversions from OPCAB to CCB are associated with a higher rate of postoperative hospital readmission and infection.

Younger age is associated with a higher risk of early periprosthetic joint infection and aseptic mechanical failure after total knee arthroplasty.

BACKGROUND: Although early aseptic mechanical failure after total knee arthroplasty has been reported in younger patients, it is unknown whether early revision due to periprosthetic joint infection is more or less frequent in this patient subgroup. The purpose of this study was to determine whether the incidence of early periprosthetic joint infection requiring revision knee surgery is significantly different in patients younger than fifty years of age compared with older patients following primary unilateral total knee arthroplasty. METHODS: A large population-based study was conducted with use of the California Patient Discharge Database, which allows serial linkage of all discharge data from nonfederal hospitals in the state over time. Patients undergoing primary unilateral total knee arthroplasty during 2005 to 2009 were identified. Principal outcomes were partial or complete revision arthroplasty due to periprosthetic joint infection or due to aseptic mechanical failure within one year. Multivariate analysis included risk adjustment for important demographic and clinical variables. The effect of hospital total knee arthroplasty volume on the outcomes of infection and mechanical failure was analyzed with use of hierarchical modeling. RESULTS: At one year, 983 (0.82%) of 120,538 primary total knee arthroplasties had undergone revision due to periprosthetic joint infection and 1385 (1.15%) had undergone revision due to aseptic mechanical failure. The cumulative incidence in patients younger than fifty years of age was 1.36% for revision due to periprosthetic joint infection and 3.49% for revision due to aseptic mechanical failure. In risk-adjusted models, the risk of periprosthetic joint infection was 1.8 times higher in patients younger than fifty years of age (odds ratio = 1.81, 95% confidence interval = 1.33 to 2.47) compared with patients sixty-five years of age or older, and the risk of aseptic mechanical failure was 4.7 times higher (odds ratio = 4.66, 95% confidence interval = 3.77 to 5.76). The rate of revision due to infection at hospitals in which a mean of more than 200 total knee arthroplasties were performed per year was lower than the expected (mean) value (p = 0.04). CONCLUSIONS: Patients younger than fifty years of age had a significantly higher risk of undergoing revision due to periprosthetic joint infection or to aseptic mechanical failure at one year after primary total knee arthroplasty.

Incidence of hospital-acquired venous thromboembolic codes in medical patients hospitalized in academic medical centers.

BACKGROUND: Hospital-acquired venous thromboembolism (HA-VTE, VTE occurring during a hospitalization) codes in hospital billing data are often used as a surrogate for hospital-associated VTE events occurring during or up to 30 days after a hospitalization, which are more difficult to measure. OBJECTIVE: Establish the incidence and composition of HA-VTE/superficial venous thrombosis (SVT) coded in a large cohort of medical patients. DESIGN: Retrospective analysis of discharges. SETTING: Eighty-three academic medical centers in UHC (formerly University HealthSystem Consortium). PATIENTS: Patients with medical diagnoses hospitalized >2 days between October 1, 2009, and March 31, 2011. MEASUREMENTS: Incidence and anatomic location of HA-VTE codes, defined as International Classification of Diseases, Ninth Revision, Clinical Modification codes for VTE coupled to a present-on-admission indicator flag set to "No." RESULTS: Among 2,525,068 medical hospitalizations, 12,847 (0.51%) cases had ≥1 thrombotic code; 2449 (19.1%) with pulmonary embolism (PE), and 3848 (30%) with lower-extremity deep venous thrombosis (LE-DVT) without PE. Upper-extremity DVT (2893; 22.5%) and SVT (3248; 25.3%) comprised the bulk of remaining cases. Among cases with HA-PE/LE-DVT, 34.3% had cancer, 47.8% received care in an intensive care unit, 78% had severe or extreme severity of illness, and 16.5% died in the hospital. Overall, 54.9% of the patients who developed a HA-PE/LE-DVT had been started on VTE pharmacoprophylaxis on hospital day 1 or 2. CONCLUSION: At academic centers, HA-VTE/SVT is coded in 0.51% of medical inpatients, and HA-PE/LE-DVT is coded in half of those. Most patients with HA-PE/LE-DVT are severely ill and develop VTE despite receiving prophylaxis.

Cause and effects of decreasing coronary revascularization procedures in California hospitals, 2006 to 2010.

Coronary revascularization procedures decreased markedly in California after the introduction of drug-eluting stents and the initiation of public reporting in 2003, resulting in a large number of low-volume heart programs. California hospital discharge data were analyzed from 2006 to 2010 to study the impact of this change. In-hospital mortality and hospital readmission for major adverse events at 90 days and 365 days were determined for patients who underwent isolated coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) either with acute coronary syndrome (ACS) or PCI without acute coronary syndrome (PCI-noACS). Three terciles were chosen by case volume as follows: high-volume (747 ± 336 [SD]/yr total PCI, 210 ± 130 isolated CABG), intermediate volume (362 ± 47 PCI, 106 ± 27 CABG), and low-volume (211 ± 6 PCI, 53 ± 17 CABG) terciles were studied. PCI-noACS procedures decreased 33% and CABG 20%, whereas PCI-ACS procedures increased slightly. Risk-adjusted in-hospital mortality was slightly better in high-volume compared with low-volume terciles for CABG (2.0% vs 2.6%) and PCI-noACS (0.64% vs 0.85%). There was no difference in major adverse events at 90 days or 365 days among volume terciles within procedure groups, and no change in event rates was noted over the 5-year period. Wide variation in outcomes, associated with low volume, contributed to poor statistical discrimination among providers. In conclusion, lower volume hospitals had similar overall outcomes with wider variation. Conservative treatment strategies apparently contributed to decreased procedure volume. Collaboration among hospitals of similar structure and case volume may be the most appropriate performance improvement model to reduce variability among providers.

Adverse events after coronary revascularization procedures in California 2000 to 2010.

Public reporting of coronary artery bypass grafting (CABG) mortality in California was initiated in 2003. Drug-eluting stents were widely introduced in the same year. Adverse events after percutaneous coronary intervention (PCI) and CABG were analyzed to study the impact of these events. Annual California hospital discharge data were collected from 2000 through 2010. In-hospital mortality and hospital readmission for adverse events <1 year were determined for patients undergoing isolated CABG, PCI for acute coronary syndrome (PCI-ACS), and all other PCIs (PCI-noACS). CABG volume peaked in 2000 and subsequently decreased by 58%; PCI volume peaked in 2005 and subsequently decreased by 20%. After 2003, in-hospital mortality and 1-year mortality for CABG decreased whereas mortality after PCI remained unchanged. Event rates for acute myocardial infarction and stroke varied little over the decade; acute myocardial infarction at 1 year was 2.5% to 2.8% (CABG), 4.5% to 5.4% (PCI-ACS), and 4.6% to 5.8% (PCI-noACS); stroke rate was 1.4% to 1.7% (CABG), 1.2% to 1.6% (PCI-ACS), and 1.0% to 1.2% (PCI-noACS). Reintervention for PCI decreased markedly, from 18.8% to 12.8% (PCI-ACS) and 22.5% to 13.3% (PCI-noACS). Multiple adverse cardiovascular and cerebral events rate at 1 year decreased from 10.8% to 9.4% (CABG), 26.5% to 21.2% (PCI-ACS), and 26.8% to 18.4% (PCI-noACS). Excluding reinterventions, multiple adverse cardiovascular and cerebral events rate at 1 year was 8.3% (CABG), 14.6% (PCI-ACS), and 10.1% (PCI-noACS) in 2010. In conclusion, the volume of coronary interventions in California decreased whereas adverse event rates decreased after the introduction of public reporting and drug-eluting stents. Lower procedure volume combined with improved outcomes resulted in an annual decrease of >6,000 adverse events by the end of the decade.