Sex-Based Differences in Outcomes With Percutaneous Transcatheter Repair of Mitral Regurgitation With the MitraClip System: Transcatheter Valve Therapy Registry From 2011 to 2017.

BACKGROUND: Women have a higher rate of adverse events after mitral valve surgery. We sought to evaluate whether outcomes after transcatheter edge-to-edge repair intervention by sex have similar trends to mitral valve surgery. METHODS: The primary outcome was 1-year major adverse events defined as a composite of all-cause mortality, stroke, and any bleeding in the overall study cohort. Patients who underwent transcatheter edge-to-edge repair for mitral regurgitation with the MitraClip system in the Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy registry were evaluated. Linked administrative claims from the Centers for Medicare and Medicaid Services were used to evaluate 1-year clinical outcomes. Associations between sex and outcomes were evaluated using a multivariable logistic regression model for in-hospital outcomes and Cox model for 1-year outcomes. RESULTS: From November 2013 to March 2017, 5295 patients, 47.6% (n=2523) of whom were female, underwent transcatheter edge-to-edge repair. Females were less likely to have >1 clip implanted (P<0.001) and had a lower adjusted odds ratio of device success (adjusted odds ratio, 0.78 [95% CI, 0.67-0.90]), driven by lower odds of residual mitral gradient <5 mm Hg (adjusted odds ratio, 0.54 [CI, 0.46-0.63]) when compared with males. At 1-year follow-up, the primary outcome did not differ by sex. Female sex was associated with lower adjusted 1-year risk of all-cause mortality (adjusted hazard ratio, 0.80 [CI, 0.68-0.94]), but the adjusted 1-year risk of stroke and any bleeding did not differ by sex. CONCLUSIONS: No difference in composite outcome of all-cause mortality, stroke, and any bleeding was observed between females and males. Adjusted 1-year all-cause mortality was lower in females compared with males.

Institutional Experience With Transcatheter Mitral Valve Repair and Clinical Outcomes: Insights From the TVT Registry.

OBJECTIVES: The aim of this study was to examine the relation between institutional experience and procedural results of transcatheter mitral valve repair. BACKGROUND: Transcatheter mitral valve repair for the treatment of mitral regurgitation (MR) is a complex procedure requiring navigation of the left atrium, left ventricle, and mitral valve apparatus using echocardiographic guidance. METHODS: MitraClip procedures from the Society of Thoracic Surgeons/American College of Cardiology TVT (Transcatheter Valve Therapy) Registry were stratified into tertiles on the basis of site-specific case sequence (1 to 18, 19 to 51, and 52 to 482). In-hospital outcomes of procedural success, procedural time, and procedural complications were examined. To evaluate the learning curve for the procedure, generalized linear mixed models were developed using case sequence number as a continuous variable. RESULTS: MitraClip procedures (n = 12,334) performed at 275 sites between November 2013 and September 2017 were analyzed. Optimal procedural success (≤1+ residual MR without mortality or need for cardiac surgery) increased across tertiles of case experience (62.0%, 65.5%, and 72.5%; p < 0.001), whereas procedural time and procedural complications decreased. Acceptable procedural success (≤2+ residual MR without death or need for cardiac surgery) also increased across tertiles of case experience, but the differences were smaller (91.2%, 91.2%; and 92.9%; p = 0.006). In the learning-curve analysis, visual inflection points for procedural time, procedural success, and procedural complications were evident after about 50 cases, with continued improvements observed up to 200 cases. CONCLUSIONS: For transcatheter mitral valve repair with the MitraClip, increasing institutional experience was associated with improvements in procedural success, procedure time, and procedural complications. The impact of institutional experience was larger when considering the goal of achieving optimal MR reduction.

Transcatheter Aortic Valve Replacement in Patients With End-Stage Renal Disease.

BACKGROUND: In patients with end-stage renal disease (ESRD), surgical aortic valve replacement is associated with higher early and late mortality, and adverse outcomes compared with patients without renal disease. Transcatheter aortic valve replacement (TAVR) offers another alternative, but there are limited reported outcomes. OBJECTIVES: The purpose of this study was to determine the outcomes of TAVR in patients with ESRD. METHODS: Among the first 72,631 patients with severe aortic stenosis (AS) treated with TAVR enrolled in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) TVT (Transcatheter Valve Therapies) registry, 3,053 (4.2%) patients had ESRD and were compared with patients who were not on dialysis for demographics, risk factors, and outcomes. RESULTS: Compared with the nondialysis patients, ESRD patients were younger (76 years vs. 83 years; p < 0.01) and had higher rates of comorbidities leading to a higher STS predicted risk of mortality (median 13.5% vs. 6.2%; p < 0.01). ESRD patients had a higher in-hospital mortality (5.1% vs. 3.4%; p < 0.01), although the observed to expected ratio was lower (0.32 vs. 0.44; p < 0.01). ESRD patients also had a similar rate of major vascular complications (4.5% vs. 4.6%; p = 0.86), but a higher rate of major bleeding (1.4% vs. 1.0%; p = 0.03). The 1-year mortality was significantly higher in dialysis patients (36.8% vs. 18.7%; p < 0.01). CONCLUSIONS: Patients undergoing TAVR with ESRD are at higher risk and had higher in-hospital mortality and bleeding, but similar vascular complications, when compared with those who are not dialysis dependent. The 1-year survival raises concerns regarding diminished benefit in this population. TAVR should be used judiciously after full discussion of the risk-benefit ratio in patients on dialysis.

Incidence, Management, and Associated Clinical Outcomes of New-Onset Atrial Fibrillation Following Transcatheter Aortic Valve Replacement: An Analysis From the STS/ACC TVT Registry.

OBJECTIVES: The aim of this study was to evaluate incidence, care patterns, and clinical outcomes in patients developing new-onset atrial fibrillation (AF) following transcatheter aortic valve replacement (TAVR). BACKGROUND: Pre-procedural AF has been associated with adverse outcomes in patients undergoing TAVR, but the incidence of new-onset AF, associated anticoagulant management, and subsequent clinical outcomes are unclear. METHODS: Using the Society of Thoracic Surgeons/American College of Cardiology TVT (Transcatheter Valve Therapy) Registry linked with Medicare claims, patients undergoing TAVR from 2011 to 2015 who developed post-procedural AF were evaluated. Patients with known AF prior to TAVR were excluded. Outcomes of interest included in-hospital mortality and stroke and all-cause mortality, stroke, and bleeding at 12 months. Multivariate adjustment was then performed to determine differences in 1-year outcomes among those with and without new post-procedural AF, stratified by anticoagulation status. RESULTS: We identified 1,138 of 13,556 patients (8.4%) who developed new onset AF (4.4% of transfemoral [TF]-access patients, 16.5% of non-TF-access patients). Patients developing AF were older, more likely female, had higher Society of Thoracic Surgeons risk scores, and were often treated using non-TF access. Despite having a median CHA2DS2-VASc score of 5 (25th and 75th percentile: 5 to 6), only 28.9% of patients with new AF were discharged on oral anticoagulation. In-hospital mortality (7.8% vs. 3.4%; p < 0.01) and stroke (4.7% vs. 2.0%; p < 0.01) were higher among patients who developed post-procedural AF compared with those who did not. At 1 year, rates of death (adjusted hazard ratio [HR]: 1.37; 95% confidence interval [CI]: 1.19 to 1.59), stroke (adjusted HR: 1.50; 95% CI: 1.14 to 1.98), and bleeding (adjusted HR: 1.24; 95% CI: 1.10 to 1.40) were higher among patients with new-onset AF. One-year mortality rates were highest among patients who developed new-onset AF but were not discharged on anticoagulation. CONCLUSIONS: Post-TAVR AF occurred in 8.4% of patients (4.4% with TF access, 16.5% with non-TF access), with fewer than one-third of patients receiving anticoagulation at discharge, and was associated with increased risk for in-hospital and 1-year mortality and stroke. Given the clinical significance of post-TAVR AF, additional studies are necessary to delineate the optimal management strategy in this high-risk population.

Outcomes Following Urgent/Emergent Transcatheter Aortic Valve Replacement: Insights From the STS/ACC TVT Registry.

OBJECTIVES: The authors sought to examine outcomes and identify independent predictors of mortality among patients undergoing urgent/emergent transcatheter aortic valve replacement (TAVR). BACKGROUND: Data on urgent/emergent TAVR as a rescue therapy for decompensated severe aortic stenosis (AS) are limited. METHODS: The Society of Thoracic Surgeons and the American College of Cardiology Transcatheter Valve Therapy (STS/ACC TVT) Registry linked with Centers for Medicare & Medicaid Services claims was used to identify patients who underwent urgent/emergent versus elective TAVR between November 2011 and June 2016. Outcomes assessed were device success rate, in-hospital major adverse events, and 30-day and 1-year mortality. Independent predictors of mortality after urgent/emergent TAVR were examined. RESULTS: Of 40,042 patients who underwent TAVR, 3,952 (9.9%) were urgent/emergent (median STS PROM score 11.8 [interquartile range: 7.6 to 17.9]). Device success rate was statistically lower, but not clinically different after urgent/emergent versus elective TAVR (92.6% vs. 93.7%; p = 0.007). Rates of major and/or life-threatening bleeding, major vascular complications, myocardial infarction, stroke, new permanent pacemaker placement, conversion to SAVR, and paravalvular regurgitation were similar between the 2 groups. Compared with elective TAVR, patients undergoing urgent/emergent TAVR had higher rates of acute kidney injury and/or new dialysis (8.2% vs. 4.2%; p < 0.001), 30-day mortality (8.7% vs. 4.3%, adjusted hazard ratio: 1.28, 95% confidence interval: 1.10 to 1.48), and 1-year mortality (29.1% vs. 17.5%, adjusted hazard ratio: 1.20, 95% confidence interval: 1.10 to 1.31). In patients undergoing urgent/emergent TAVR, non-femoral access and cardiopulmonary bypass were associated with increased risk, whereas use of balloon-expandable valve was associated with decreased risk of 30-day and 1-year mortality. CONCLUSIONS: Urgent/emergent TAVR is feasible with acceptable outcomes and may be a reasonable option in a selected group of patients with severe AS.

Procedural Experience for Transcatheter Aortic Valve Replacement and Relation to Outcomes: The STS/ACC TVT Registry.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has been introduced into U.S. clinical practice with efforts to optimize outcomes and minimize the learning curve. OBJECTIVES: The goal of this study was to assess the degree to which increasing experience during the introduction of this procedure, separated from other outcome determinants including patient and procedural characteristics, is associated with outcomes. METHODS: The authors evaluated the association of hospital TAVR volume and patient outcomes for TAVR by using data from 42,988 commercial procedures conducted at 395 hospitals submitting to the Transcatheter Valve Therapy Registry from 2011 through 2015. Outcomes assessed included adjusted and unadjusted in-hospital major adverse events. RESULTS: Increasing site volume was associated with lower in-hospital risk-adjusted outcomes, including mortality (p < 0.02), vascular complications (p < 0.003), and bleeding (p < 0.001) but was not associated with stroke (p = 0.14). From the first case to the 400th case in the volume-outcome model, risk-adjusted adverse outcomes declined, including mortality (3.57% to 2.15%), bleeding (9.56% to 5.08%), vascular complications (6.11% to 4.20%), and stroke (2.03% to 1.66%). Vascular and bleeding volume-outcome associations were nonlinear with a higher risk of adverse outcomes in the first 100 cases. An association of procedure volume with risk-adjusted outcomes was also seen in the subgroup having transfemoral access. CONCLUSIONS: The initial adoption of TAVR into practice in the United States showed that increasing experience was associated with better outcomes. This association, whether deemed a prolonged learning curve or a manifestation of a volume-outcome relationship, suggested that concentrating experience in higher volume heart valve centers might be a means of improving outcomes. (STS/ACC Transcatheter Valve Therapy Registry [TVT Registry]; NCT01737528).

Transcatheter Versus Surgical Aortic Valve Replacement: Propensity-Matched Comparison.

BACKGROUND: Randomized trials support the use of transcatheter aortic valve replacement (TAVR) for the treatment of aortic stenosis in high- and intermediate-risk patients, but the generalizability of those results in clinical practice has been challenged. OBJECTIVES: The aim of this study was to determine the safety and effectiveness of TAVR versus surgical aortic valve replacement (SAVR), particularly in intermediate- and high-risk patients, in a nationally representative real-world cohort. METHODS: Using data from the Transcatheter Valve Therapy Registry and Society of Thoracic Surgeons National Database linked to Medicare administrative claims for follow-up, 9,464 propensity-matched intermediate- and high-risk (Society of Thoracic Surgeons Predicted Risk of Mortality score ≥3%) U.S. patients who underwent commercial TAVR or SAVR were examined. Death, stroke, and days alive and out of the hospital to 1 year were compared, as well as discharge home, with subgroup analyses by surgical risk, demographics, and comorbidities. RESULTS: In a propensity-matched cohort (median age 82 years, 48% women, median Society of Thoracic Surgeons Predicted Risk of Mortality score 5.6%), TAVR and SAVR patients experienced no difference in 1-year rates of death (17.3% vs. 17.9%; hazard ratio: 0.93; 95% confidence interval [CI]: 0.83 to 1.04) and stroke (4.2% vs. 3.3%; hazard ratio: 1.18; 95% CI: 0.95 to 1.47), and no difference was observed in the proportion of days alive and out of the hospital to 1 year (rate ratio: 1.00; 95% CI: 0.98 to 1.02). However, TAVR patients were more likely to be discharged home after treatment (69.9% vs. 41.2%; odds ratio: 3.19; 95% CI: 2.84 to 3.58). Results were consistent across most subgroups, including among intermediate- and high-risk patients. CONCLUSIONS: Among unselected intermediate- and high-risk patients, TAVR and SAVR resulted in similar rates of death, stroke, and DAOH to 1 year, but TAVR patients were more likely to be discharged home.

Assessment of Operator Variability in Risk-Standardized Mortality Following Percutaneous Coronary Intervention: A Report From the NCDR.

OBJECTIVES: This study sought to determine variability and stability in risk-standardized mortality rates (RSMR) of percutaneous coronary intervention (PCI) operators meeting minimum case volume standards and identify differences in case mix and practice patterns that may account for RSMR variability. BACKGROUND: RSMR has been suggested as a metric to evaluate the performance of PCI operators; however, variability of operator-level RSMR and the stability of this metric over time among the same operator are unknown. METHODS: The authors calculated mean RSMRs for PCI operators with average annual volume of ≥50 cases in the National Cardiovascular Data Registry CathPCI Registry. Funnel plots were used to account for operator case volume. Demographic, clinical, and treatment variables of patients treated by operators with outlying high or low RSMRs (identified by RMSR greater than or less than 2 σ above or below the mean [analogous to 2 SD], respectively) were compared with nonoutlier operators. RMSR stability was assessed by calculating average annual operator RMSR during the study period and by determining if operators were consistently classified into RMSR categories in each year. RESULTS: Between October 1, 2009, and September 30, 2014, a total of 2,352,174 PCIs were performed at 1,373 hospitals by 3,760 operators. Of these, 242 operators (6.5%) had RSMR >2 σ above the mean and 156 operators (4.1%) had RSMR >2 σ below the mean. Both high and low RSMR outlier operators treated patients with lower expected mortality risk, compared with nonoutlier operators. There was significant instability in annual operator RMSR during the study period. CONCLUSIONS: There is significant variability in risk-standardized PCI mortality among U.S. operators meeting minimum volume standards that is not explained by case mix or procedure characteristics. Operator RMSR was unstable from year to year, thus limiting its utility as a sole performance measure for PCI quality.

Use and Effectiveness of Bivalirudin Versus Unfractionated Heparin for Percutaneous Coronary Intervention Among Patients With ST-Segment Elevation Myocardial Infarction in the United States.

OBJECTIVES: The purpose of this study was to describe temporal trends and determine the comparative effectiveness of bivalirudin versus unfractionated heparin (UFH) during percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Several clinical trials have compared the safety and effectiveness of bivalirudin versus UFH during PCI for STEMI, but results have been conflicting. METHODS: Trends in anticoagulant use were examined among 513,775 PCIs for STEMI from July 2009 through December 2014 within the National Cardiovascular Data Registry CathPCI Registry. We conducted an instrumental variable analysis comparing bivalirudin with UFH, using operator preference for bivalirudin as the instrument. We used a test of mediation to determine the extent to which differences in outcomes between anticoagulants were due to differences in use of glycoprotein IIb/IIIa inhibitors (GPI). Primary outcomes were in-hospital bleeding and mortality. RESULTS: Bivalirudin use increased from 2009 through 2013, followed by a new decline. GPIs were used in 74.7% of UFH PCIs versus 26.5% of bivalirudin PCIs. In unadjusted analyses, bivalirudin was associated with decreased bleeding (risk difference [RD]: -4.2%; p < 0.001) and mortality (RD: -0.84%; p < 0.001). After instrumental variable analyses, bivalirudin remained associated with less bleeding (RD: -3.75%; p < 0.001), but not mortality (RD: -0.10%; p = 0.280). The higher rate of GPI use with UFH was responsible for more than one-half of bivalrudin's bleeding reduction (GPI-adjusted RD: -1.57%; p < 0.001). Bleeding reductions were negligible for transradial PCI (RD: -0.11%; p = 0.842). CONCLUSIONS: The use of bivalirudin during STEMI has decreased. Bivalirudin was associated with reduced bleeding and no mortality difference. The bleeding reduction with bivalirudin was largely explained by the greater use of GPIs with UFH.

Impact of Ejection Fraction and Aortic Valve Gradient on Outcomes of Transcatheter Aortic Valve Replacement.

BACKGROUND: In patients with aortic stenosis undergoing transcatheter aortic valve replacement (TAVR), studies have suggested that reduced left ventricular (LV) ejection fraction (LVEF) and low aortic valve gradient (AVG) are associated with worse long-term outcomes. Because these conditions commonly coexist, the extent to which they are independently associated with outcomes after TAVR is unknown. OBJECTIVES: The purpose of this study was to evaluate the impact of LVEF and AVG on clinical outcomes after TAVR and to determine whether the effect of AVG on outcomes is modified by LVEF. METHODS: Using data from 11,292 patients who underwent TAVR as part of the Transcatheter Valve Therapies Registry, we examined rates of 1-year mortality and recurrent heart failure in patients with varying levels of LV dysfunction (LVEF <30% vs. 30% to 50% vs. >50%) and AVG (<40 mm Hg vs. ≥40 mm Hg). Multivariable models were used to estimate the independent effect of AVG and LVEF on outcomes. RESULTS: During the first year of follow-up after TAVR, patients with LV dysfunction and low AVG had higher rates of death and recurrent heart failure. After adjustment for other clinical factors, only low AVG was associated with higher mortality (hazard ratio: 1.21; 95% confidence interval: 1.11 to 1.32; p < 0.001) and higher rates of heart failure (hazard ratio: 1.52; 95% confidence interval: 1.36 to 1.69; p <0.001), whereas the effect of LVEF was no longer significant. There was no evidence of effect modification between AVG and LVEF with respect to either endpoint. CONCLUSIONS: In this series of real-world patients undergoing TAVR, low AVG, but not LV dysfunction, was associated with higher rates of mortality and recurrent heart failure. Although these findings suggest that AVG should be considered when evaluating the risks and benefits of TAVR for individual patients, neither severe LV dysfunction nor low AVG alone or in combination provide sufficient prognostic discrimination to preclude treatment with TAVR.

Temporal Trends in the Risk Profile of Patients Undergoing Outpatient Percutaneous Coronary Intervention: A Report from the National Cardiovascular Data Registry's CathPCI Registry.

BACKGROUND: Because of recent changes in criteria for coverage for inpatient hospital stays, most nonacute percutaneous coronary intervention (PCI) procedures are reimbursed on an outpatient basis regardless of underlying patient risk. Downstream effects of these changes on the risk profile of patients undergoing outpatient PCI have not been evaluated. METHODS AND RESULTS: Using the American College of Cardiology National Cardiovascular Data Registry's CathPCI Registry, we assessed temporal trends in risk profiles and rates of hospital admission among 999 279 patients undergoing PCI qualifying for outpatient reimbursement. We estimated mortality and bleeding risk using validated models from the registry. From 2009 to 2014, the proportion of outpatients not admitted to a hospital after PCI increased from 32.8% to 66.3% (P<0.001). Patients who were admitted after PCI were older, had greater comorbidities, and experienced more post-PCI complications (all P<0.001). Among those not admitted, the proportion of patients at high risk for predicted mortality increased significantly from 17.0% to 19.8% during the study period (P<0.001). In contrast, 16.7% of patients admitted after PCI were at low risk for mortality. CONCLUSIONS: Among patients undergoing PCI procedures that qualify for outpatient reimbursement, there has been a temporal decrease in postprocedure hospital admission. Concomitantly, the proportion of these outpatients at high risk for mortality has significantly increased over time. These data suggest that current reimbursement classification could be improved by incorporating patient risk to appropriately match the necessary resources to the needed level of care.

Association of Patient-Reported Health Status With Long-Term Mortality After Transcatheter Aortic Valve Replacement: Report From the STS/ACC TVT Registry.

BACKGROUND: Although transcatheter aortic valve replacement (TAVR) is an effective treatment for aortic stenosis, long-term mortality after TAVR remains high and challenging to predict. The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a health status measure, assessed directly from patients, that integrates 2 clinically relevant factors (symptoms and functional status) that may predict TAVR outcomes. METHODS AND RESULTS: Among 7769 patients from 286 sites in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry, we examined the association between preprocedure (baseline) patient health status, as assessed by the KCCQ, and 1-year mortality after TAVR. The KCCQ Overall Summary Score was categorized as very poor: <25, poor: 25 to 49, fair: 50 to 74, or good: ≥75. Before TAVR, health status was rated as very poor in 28%, poor in 38%, fair in 24%, and good in 10%. Patients with worse health status were more likely to be women and had more comorbidities and higher STS mortality risk scores. Compared with those with good health status before TAVR and after adjusting for a broad range of baseline covariates, patients with very poor health status had a 2-fold increased hazard of death over the first year after TAVR (adjusted hazard ratio, 2.00; 95% confidence interval, 1.58-2.54), whereas those with poor and fair health status had intermediate outcomes (adjusted hazard ratio, 1.54; 95% confidence interval, 1.22-1.95 and adjusted hazard ratio, 1.20; 95% confidence interval, 0.94-1.55, respectively). CONCLUSIONS: In a national, contemporary practice cohort, worse preprocedure patient health status, as assessed by the KCCQ, was associated with greater long-term mortality after TAVR. These results support the measurement and integration of the KCCQ into mortality risk assessments for patients considering TAVR.

Outcomes of Patients With Severe Chronic Lung Disease Who Are Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: In this study, we sought to determine the clinical outcomes after transcatheter aortic valve replacement (TAVR) among patients with chronic lung disease (CLD) and to evaluate the safety of transaortic versus transapical alternate access approaches in patients with varying severities of CLD. METHODS: Clinical records for patients undergoing TAVR from 2011 to 2014 in The Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry were linked to Medicare hospital claims (n = 11,656). Clinical outcomes were evaluated across strata of CLD severity, and the risk-adjusted association between access route and post-TAVR mortality was determined among patients with severe CLD. RESULTS: In this cohort (median age, 84 years; 51.7% female), moderate to severe CLD was present in 27.7% (14.3%, moderate; 13.4%, severe). Compared with patients with no or mild CLD, patients with severe CLD had a higher rate of post-TAVR mortality to 1-year (32.3% versus 21.0%; adjusted hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.31 to 1.66), as did those with moderate CLD (25.5%; adjusted HR, 1.16; 95% CI, 1.03 to 1.30). The adjusted rate of mortality was similar for transapical versus transaortic approaches to 1 year (adjusted HR, 1.17; 95% CI, 0.83 to 1.65). CONCLUSIONS: Moderate or severe CLD is associated with an increased risk of death to 1-year after TAVR, and among patients with severe CLD, the risk of death appears to be similar with either transapical or transaortic alternate-access approaches. Further study is necessary to understand strategies to mitigate risk associated with CLD and the long-term implications of these findings.

Gaps in referral to cardiac rehabilitation of patients undergoing percutaneous coronary intervention in the United States.

BACKGROUND: Rates of referral to cardiac rehabilitation after percutaneous coronary intervention (PCI) have been historically low despite the evidence that rehabilitation is associated with lower mortality in PCI patients. OBJECTIVES: This study sought to determine the prevalence of and factors associated with referral to cardiac rehabilitation in a national PCI cohort, and to assess the association between insurance status and referral patterns. METHODS: Consecutive patients who underwent PCI and survived to hospital discharge in the National Cardiovascular Data Registry between July 1, 2009 and March 31, 2012 were analyzed. Cardiac rehabilitation referral rates, and patient and institutional factors associated with referral were evaluated for the total study population and for a subset of Medicare patients presenting with acute myocardial infarction. RESULTS: Patients who underwent PCI (n = 1,432,399) at 1,310 participating hospitals were assessed. Cardiac rehabilitation referral rates were 59.2% and 66.0% for the overall population and the AMI/Medicare subgroup, respectively. In multivariable analyses, presentation with ST-segment elevation myocardial infarction (odds ratio 2.99; 95% confidence interval: 2.92 to 3.06) and non-ST-segment elevation myocardial infarction (odds ratio: 1.99; 95% confidence interval: 1.94 to 2.03) were associated with increased odds of referral to cardiac rehabilitation. Models adjusted for insurance status showed significant site-specific variability in referral rates, with more than one-quarter of all hospitals referring <20% of patients. CONCLUSIONS: Approximately 60% of patients undergoing PCI in the United States are referred for cardiac rehabilitation. Site-specific variation in referral rates is significant and is unexplained by insurance coverage. These findings highlight the potential need for hospital-level interventions to improve cardiac rehabilitation referral rates after PCI.

Antiarrhythmic drug use in patients <65 years with atrial fibrillation and without structural heart disease.

Little is known in clinical practice about antiarrhythmic drug (AAD) use in patients with atrial fibrillation (AF) (particularly younger ones) who do not have structural heart disease. Using the MarketScan database, we identified patients <65 years without known coronary artery disease or heart failure who had an AAD prescription claim (class Ic drug, amiodarone, sotalol, or dronedarone) after their first AF encounter. A multinomial logistic regression model was created to assess factors associated with using each available AAD compared with using class Ic drugs before and after dronedarone was marketed in the United States. Additionally, we used the Kaplan-Meier method to determine the rates of change in AAD use and discontinuation during the year after AAD initiation. Of 8,562 patients with AF, 35% received class Ic drugs, 34% amiodarone, 24% sotalol, and 7% dronedarone. The median patient age was 56 (interquartile range 49 to 61), and 34% were women. Both before and after dronedarone was marketed, there was a statistically significant lower likelihood of class Ic drug use versus other AAD use with increasing age, inpatient index AF encounter, and previous or concomitant anticoagulation therapy. During the 1 year after AAD initiation, the AAD change rate was 14% for class Ic drugs, 8% for amiodarone, 17% for sotalol, and 18% for dronedarone (p <0.001); the AAD discontinuation rate was 40% for class Ic drugs, 52% for amiodarone, 40% for sotalol, and 69% for dronedarone (p <0.001). In conclusion, we found extensive use of amiodarone that may be inconsistent with guideline recommendations and unexpectedly high rates of AAD discontinuation.

Effects of spin-orbit coupling on magnetic properties of discrete and extended magnetic systems.

In accounting for the magnetic properties of discrete and extended compounds with unpaired spins, it is crucial to know the nature of their ground and low-lying excited states. In this review we surveyed quantum mechanical descriptions on how these states are affected by spin-orbit coupling and attempted to provide a conceptual framework with which to think about spin-orbit coupling and its applications.

On the anisotropy of the magnetic properties of CsYbZnSe3.

DC magnetic susceptibility measurements on CsYbZnSe 3 show a broad magnetic transition at approximately 10 K and pronounced differences between zero-field-cooled and field-cooled data that lead to experimental effective magnetic moments of 4.26(5) BM and 4.39(4) BM, respectively. Specific heat measurements confirm that there is neither long-range ordering nor a phase transition between 1.8 and 380 K. First-principles electronic structure calculations with and without inclusion of spin-orbit coupling effects show that the spins of CsYbZnSe 3 prefer to orient along [010] rather than along either [100] or [001] of this orthorhombic material and that the spin exchange between adjacent Yb3+ ions along [100] is substantially antiferromagnetic. The magnetic properties of CsYbZnSe 3 are best described by an Ising uniform antiferromagnetic chain model.

On the relevance of an antiferromagnetic dimer model for the spin-gapped magnetic solids Cu(terpy)Mo2O7 and Cu(OH)(p-pyc)H2O.

The magnetic solids Cu(terpy)Mo2O7 (terpy = terpyridine) and Cu(OH)(p-pyc)H2O (p-pyc = p-pyridinecarboxylate) have a spin gap and possess chains of Cu2+ ions in which two different Cu...Cu distances alternate. On the basis of their reported crystal structures, the spin-exchange interactions of these compounds were examined by performing spin dimer analysis to determine whether an antiferromagnetic dimer or an alternating antiferromagnetic chain model is appropriate for their magnetic properties. Our analysis shows that an antiferromagnetic dimer model is correct for both compounds because of the anisotropic overlap between the magnetic orbitals of their Cu2+ sites.

On the disorder of the Cl atom position in and its probable effect on the magnetic properties of (CuCl)LaNb2O7.

The magnetic susceptibility of (CuCl)LaNb2O7 shows a spin gap despite the Cu(2+) ions in each CuClO2 layer forming a square lattice. To account for this observation, we explored implications of the disorder of the Cl-atom position in (CuCl)LaNb2O7 by considering possible ordered structures of CuCl4O2 octahedra in each CuClO2 layer, by identifying various spin exchange interactions of a CuClO2 layer and by estimating the relative strengths of these interactions in terms of spin dimer analysis. We then probed what kind of spin lattice is required for each CuClO2 layer to have a spin gap on the basis of the classical spin approximation. Our study suggests that the CuCl4O2 octahedra of each CuClO2 layer should be arranged such that the resulting spin lattice does not have uniform chains but ring clusters containing an even number of Cu atoms. Implications of this conclusion were discussed on the basis of the recently reported neutron scattering and magnetization studies of (CuCl)LaNb2O7.

Comparison of the crystal structures and magnetic properties of the low- and high-temperature forms of AgCuPO4: crystal structure determination, magnetic susceptibility measurements, and spin dimer analysis.

The crystal structure of the low-temperature form of AgCuPO4 (i.e., alpha-AgCuPO4) was determined by powder X-ray diffraction and was compared with that of the high-temperature form of AgCuPO4 (i.e., beta-AgCuPO4). The magnetic properties of the two forms were examined by measuring their magnetic susceptibilities and evaluating the relative strengths of their spin-exchange interactions on the basis of spin-dimer analysis. Both forms of AgCuPO4 have layers of Cu2P2O8 alternating with silver-atom double layers; beta-AgCuPO4 has two Cu2P2O8 layers per unit cell, while alpha-AgCuPO4 has one. The coordinate environment of each Cu2+ ion is close to being a distorted square pyramid in alpha-AgCuPO4, but it is close to being a distorted trigonal bipyramid in beta-AgCuPO4. The magnetic susceptibilities of alpha- and beta-AgCuPO4 are well simulated by an antiferromagnetic alternating-chain model, which leads to J/k(B) = -146.1 K and alphaJ/k(B) = -75.8 K for alpha-AgCuPO4, and J/k(B) = -82.6 K and alphaJ/k(B) = -31.7 K for beta-AgCuPO4 (with the convention in which the spin-exchange parameter between two adjacent spin sites is written as 2J). The spin gaps, delta/k(B), obtained from these parameters are 93.7 K for alpha-AgCuPO4 and 62.3 K for beta-AgCuPO4. The strongest spin exchange in both forms of AgCuPO4 comes from a super-superexchange path, and this interaction is stronger for alpha-AgCuPO4 than for beta-AgCuPO4 by a factor of approximately 2, in good agreement with the experiment. Our analysis supports the use of this model for beta-AgCuPO4 and indicates that the spin lattice of alpha-AgCuPO4 would be better described by a two-dimensional net made up of weakly interacting alternating chains.