Author + information
- Received July 22, 2015
- Accepted July 30, 2015
- Published online November 1, 2015.
- Luis Nombela-Franco, MD∗,
- María del Trigo, MD†,
- Guillermo Morrison-Polo, MD∗,
- Gabriela Veiga, MD†,
- Pilar Jimenez-Quevedo, MD, PhD∗,
- Omar Abdul-Jawad Altisent, MD†,
- Francisco Campelo-Parada, MD†,
- Corina Biagioni, MD∗,
- Rishi Puri, MBBS, PhD†,
- Robert DeLarochellière, MD†,
- Eric Dumont, MD†,
- Daniel Doyle, MD†,
- Jean-Michel Paradis, MD†,
- Alicia Quirós, PhD∗,
- Carlos Almeria, MD∗,
- Nieves Gonzalo, MD, PhD∗,
- Ivan Nuñez-Gil, MD, PhD∗,
- Pablo Salinas, MD, PhD∗,
- Siamak Mohammadi, MD†,
- Javier Escaned, MD, PhD∗,
- Antonio Fernández-Ortiz, MD, PhD∗,
- Carlos Macaya, MD, PhD∗ and
- Josep Rodés-Cabau, MD†∗ ()
- ∗Cardiovascular Institute, Hospital Clínico San Carlos, Madrid, Spain
- †Quebec Heart & Lung Institute, Quebec City, Quebec, Canada
- ↵∗Reprint requests and correspondence:
Dr. Josep Rodés-Cabau, Quebec Heart & Lung Institute, 2725 chemin Ste-Foy, Quebec City, Quebec G1V 4G5, Canada.
Objectives The aim of this study was to determine the incidence, causes, and predictors of unplanned hospital readmissions after transcatheter aortic valve replacement (TAVR).
Background Data regarding unplanned hospital readmissions after TAVR in a real-world all-comers population are scarce.
Methods A total of 720 consecutive patients undergoing TAVR at 2 centers who survived the procedure, were included. Median follow-up was 23 months (interquartile range [IQR]: 12 to 39 months), available in 99.9% of the initial population. The occurrence, timing, and causes of hospital readmission within the first year post-TAVR were obtained in all cases. Early and late readmissions were defined as those occurring ≤30 days and >30 days to 1 year post-TAVR, respectively.
Results There were 506 unplanned readmissions in 316 patients (43.9%) within the first year post-TAVR (median time: 63 days; IQR: 19 to 158 days post-discharge). Of these, early readmission occurred in 105 patients (14.6%), and 118 patients (16.4%) had multiple (≥2) readmissions. Readmissions were due to noncardiac and cardiac causes in 59% and 41% of cases, respectively. Noncardiac readmissions included, in order of decreasing frequency, respiratory, infection, and bleeding events as the main causes, whereas heart failure and arrhythmias accounted for most cardiac readmissions. The predictors of early readmission were periprocedural major bleeding complications (p = 0.001), anemia (p = 0.019), lower left ventricular ejection fraction (p = 0.042), and the combined presence of antiplatelet and anticoagulation therapy at hospital discharge (p = 0.014). The predictors of late readmission were chronic obstructive pulmonary disease (p = 0.001), peripheral vascular disease (p = 0.023), chronic renal failure (p = 0.013), and atrial fibrillation (p = 0.012). Early readmission was an independent predictor of mortality during the follow-up period (hazard ratio: 1.56, 95% confidence interval: 1.02 to 2.39, p = 0.043).
Conclusions The readmission burden after TAVR in an all-comers population was high. Nearly one-fifth of the patients were readmitted early after hospital discharge, increasing the risk of mortality at follow-up. Reasons for readmission were split between noncardiac and cardiac causes, with respiratory causes and heart failure as the main diagnoses in each group, respectively. Whereas early readmissions were mainly related to periprocedural bleeding events, most late readmissions were secondary to baseline patient comorbidities. These results underscore the importance of and provide the basis for implementing specific preventive measures to reduce readmission rates after TAVR.
- aortic stenosis
- bleeding events
- transcatheter aortic valve implantation
- transcatheter aortic valve replacement
Unplanned readmissions after initial hospitalization are frequent, significantly affecting clinical outcomes, patient quality of life, and health care costs (1,2). Early (within 30 days of discharge) readmissions have generated significant debate. As many as 20% of Medicare beneficiaries are readmitted within 30 days after an index hospitalization, and this has been associated with additional health care costs exceeding $15 billion (1). Of note, the rate of early unplanned readmissions has been considered a marker of quality of care and hospital performance (3,4), and the subject of provider payment restrictions in the United States. Identifying the timing, causes, and predictors of unplanned readmissions is thus fundamental for implementing appropriate preventive measures.
Transcatheter aortic valve replacement (TAVR) is currently the standard treatment for severe aortic stenosis in symptomatic patients with prohibitive or high surgical risk (5). The significant burden of comorbidities in patients currently undergoing TAVR, as well as the relatively high rate of periprocedural complications, engenders a high likelihood of hospital readmissions in such patients. However, data on unplanned readmissions after TAVR are scarce, particularly regarding the timing, specific causes, and predictors of readmission. More importantly, no data exist on 30-day readmissions after TAVR apart from reporting its incidence (6–8). The objectives of this study were to determine the incidence, causes, and predictive factors of unplanned hospital readmissions after TAVR, with a specific focus on readmissions within the 30-day and 1-year periods.
A total of 893 consecutive patients with symptomatic severe aortic stenosis who underwent TAVR at 2 centers were evaluated for the study. Of these, patients who died before hospital discharge (n = 65) or those with follow-up of less than 1 year (n = 108) were excluded, leading to a final population of 720 patients. The indications for TAVR and procedural approach were assessed by each center’s heart team composed of interventional cardiologists and cardiac surgeons. The TAVR procedures were performed using balloon- and self-expanding valves, as previously described (5). In-hospital and follow-up data were prospectively entered in a dedicated database. Clinical outcomes were defined according to Valve Academic Research Consortium-2 criteria (9). All patients signed informed consent forms before the procedure, and all studies were performed in accordance with the local ethics committee of each center.
Clinical follow-up was carried out during pre-scheduled outpatient clinic visits or by telephone contact at 1, 6, and 12 months post-TAVR and yearly thereafter. Records from referring cardiologists, general practitioners, and other hospitals were consulted whenever necessary for further information. Complete information about readmissions within the last follow-up was obtained in 99.9% of patients (1 patient was lost to follow-up). The median length of follow-up of the study population was 23 months (interquartile range [IQR]: 12 to 39 months).
Readmissions were defined as a patient being admitted to a hospital ward or an intensive care unit. Visits to the emergency department or admission to a day-stay hospital were excluded from the current analysis. Readmission date, duration of hospital stay, primary and secondary reasons for hospitalization, and in-hospital death were recorded after a detailed medical records review. The primary diagnosis on the discharge report was used to determine the main cause of readmission. Causes of readmission were grouped as being of cardiac or noncardiac origin. Cardiac causes included the following: heart failure, acute coronary syndrome (unstable angina or myocardial infarction), arrhythmia, and prosthesis related (endocarditis, valve thrombosis, structural failure of the valve requiring intervention). Noncardiac causes were classified as follows: respiratory (including pneumonia), bleeding, cerebrovascular event (ischemic or hemorrhagic stroke, transient ischemic attack), peripheral vascular events, infections, trauma, and other.
Time to readmission was calculated as the time between the date of hospital discharge after the index TAVR procedure (time 0) and the first hospital readmission day. Readmissions were also classified according to the timing as early (≤30 days) or late (between 30 days and 12 months). Multiple readmissions were defined as ≥2 readmissions.
Categorical variables were expressed as number (percentage) and continuous variables as mean ± SD or median (IQR: 25th to 75th percentiles) according to their distribution. Assessment of normality for continuous data was performed using the Shapiro-Wilks test. Comparison of numerical variables was performed with the 2-sided Student t test or Wilcoxon rank sum test, and the chi-square or Fisher exact test was used to compare qualitative variables. We determined unadjusted all-cause early, late, and overall readmission rates. Analysis of the predictors of hospital readmissions was performed using the conditional Prentice-Williams-Peterson model (10) to account for multiple events. Variables with a p value <0.05 on univariate analysis were entered into a logistic regression analysis to determine the independent predictors of early, late, and overall readmissions. Univariate and multivariate competing-risk (mortality not occurring during a hospital admission) regression analyses were done to determine the predictors of readmissions. Freedom from readmission and mortality curves were calculated with the Kaplan-Meier method, and comparison between groups was performed with the log-rank test. A landmark analysis excluding patients who died at <30 days was used to further investigate the impact of early readmission on 2-year mortality. A p value <0.05 was considered significant for all statistical tests. All data were analyzed with the Statistical Package for Social Sciences version 20.0 (SPSS Inc., IBM, Armonk, New York) and the R statistical software, version 3.0.2 (R Foundation for Statistical Computing, Vienna, Austria).
The main baseline, procedural characteristics, and in-hospital complications of the study population are shown in Table 1.
Incidence, timing, and causes of hospital readmissions
A total of 316 patients (43.9%) were readmitted during the first year after the index TAVR procedure, with a total of 506 readmission episodes (70.4% total readmissions per index discharge and 1.6 episodes per admitted patient). A total of 198 patients (27.5%) experienced 1 readmission, and 118 patients (16.4%) had multiple (≥2) readmissions, ranging from 2 to 7. The median time from the TAVR procedure discharge to the first readmission was 63 days (IQR: 19 to 157 days). The median length of stay per readmission was 7 (IQR: 4 to 13 days).
The timing of hospital readmission within the year after TAVR is shown in Figure 1. Early (≤30 days) readmission occurred in 105 patients (14.6%) with 115 readmission episodes (10 patients had 2 readmissions). This represented 33.2% of total readmitted patients within the year after TAVR. As many as 41 patients (5.7%) were readmitted within the 7 days after TAVR. A total of 88 patients were readmitted between 30 days and 3 months, leading to a readmission rate of 26.8% within the 3 months after TAVR. An additional 123 patients (17.1%) required hospital readmission between 3 and 12 months after TAVR.
The causes of readmission within the first year are summarized overall and according to timing in Table 2. Of 506 readmission episodes, 298 (58.9%) were due to noncardiac causes, mostly respiratory (20.1%), infection (15.4%), and bleeding (12.1%) events. Cardiac origin accounted for 208 readmission episodes (41.1%), mainly due to heart failure (56.7%) and arrhythmic events (21.2%). Bradyarrhythmias accounted for 18 events, and tachyarrhythmias accounted for 28 events (17 atrial arrhythmias and 9 ventricular arrhythmias). One-fourth of readmissions due to cardiac reasons required an invasive procedure.
Early readmissions were also predominantly noncardiac in origin (57.4%), secondary to infections (18.2%, mainly access-site infections) and respiratory (16.7%) or bleeding (15.1%) events. Cardiac causes accounted for 42.6% of early readmissions, with the vast majority of patients being readmitted because of heart failure (71.4%). There were no differences between the main causes (cardiac vs. noncardiac) of early and late readmission after TAVR (p = 0.71). However, from the perspective of cardiac etiology–driven readmissions, heart failure was more frequently a cause of early instead of late readmission (p = 0.018).
The Kaplan-Meier curves of readmission events (patient based) over time overall and according to the underlying causes (cardiac vs. non-cardiac) are shown in Figure 2.
Predictors of hospital readmission
The predictors of early and late hospital readmission after TAVR are shown in Tables 3 and 4, respectively. The independent predictors of early readmissions were procedural complications deemed major or life-threatening bleeding (hazard ratio [HR]: 2.41, 95% confidence interval [CI]: 1.57 to 3.70; p = 0.001), left ventricular ejection fraction (HR: 1.08 for each decrease of 5%, 95% CI: 1.00 to 1.17; p = 0.042), hemoglobin levels (HR: 1.19 for each decrease of 1 g/dl, 95% CI: 1.03 to 1.39; p = 0.019), and combination antithrombotic therapy (anticoagulation + antiplatelet) (HR: 1.62, 95% CI: 1.10 to 2.39; p = 0.014) at hospital discharge. The independent predictors of late readmissions were chronic obstructive pulmonary disease (HR: 1.49, 95% CI: 1.21 to 1.84; p = 0.001), atrial fibrillation (HR: 1.32, 95% CI: 1.06 to 1.63; p = 0.012), peripheral vascular disease (HR: 1.29, 95% CI: 1.04 to 1.61; p = 0.023), and renal function at hospital discharge (HR: 1.05 for each eGFR decrease of 10 ml/min, 95% CI: 1.01 to 1.09; p = 0.013). The factors independently associated with multiple (≥2 vs. 1) readmissions within 1 year were lower mean gradient at baseline (HR: 1.08, 95% CI: 1.02 to 1.15; p = 0.011) and major or life-threatening bleeding (HR: 2.36, 95% CI: 1.50 to 3.71; p = 0.001).
Readmissions and mortality
A total of 44 patients (13.9%) died during a readmission episode (25 of them [7.9%] during the first readmission episode).
In a sensitivity analysis, we evaluated the impact of 30-day readmissions on 30-day to 2-year mortality. The mortality rate at 2-year follow-up was 20.8% (95% CI: 17.5% to 24.1%). In those patients readmitted within 30 days after TAVR, the mortality rate at 2 years was 30.2% (95% CI: 20.4% to 40.0%) compared with 19.2% (95% CI: 15.7% to 22.7%) in those without 30-day readmission (log-rank p = 0.002) (Figure 3). Early readmission was a factor associated with a higher mortality rate (30-day to 2-year) (HR: 1.89, 95% CI: 1.25 to 2.87; p = 0.003), and this association persisted after adjusting for confounding factors in a multivariable analysis (Table 5).
Almost one-half of the patients undergoing TAVR were readmitted within the first year after the procedure, and about one-fourth of such readmissions occurred within the first 30 days post-TAVR (30-day readmission rate, ∼15%). Multiple readmissions were observed in more than one-third of such patients. Most (∼60%) readmissions were due to noncardiac causes, with respiratory failure, infection, and bleeding events accounting for more than one-half of such events. Approximately 40% of readmissions were secondary to cardiac causes, with heart failure accounting for more than one-half of such cases. Readmissions requiring prosthetic valve reintervention were infrequent. Although periprocedural bleeding complications, anemia, lower left ventricular ejection fraction, and more intensive antithrombotic treatment regimen on hospital discharge were the main predictors of 30-day readmissions, baseline comorbidities such as chronic obstructive pulmonary disease, renal failure, peripheral vascular disease, and atrial fibrillation identified a group of patients with a higher likelihood of delayed readmission. Patients requiring early rehospitalization had a higher mortality risk during the follow-up period.
Several studies have evaluated 30-day readmission rates after cardiac interventions. These ranged from 9% to 24% after percutaneous coronary interventions and cardiac surgery (11–16). In patients undergoing isolated aortic valve replacement, the 30-day readmission rates were ∼20% (16), marginally higher than the 15% rate observed in our study. According to our findings, Holmes et al. (6) reported a 30-day readmission rate of 17% in a large series of real-world consecutive patients who underwent TAVR in the TVT (Transcatheter Valve Therapies) registry. At 1-year follow-up, the readmission rate increased to nearly 50%, similar to the 44% reported in the present analysis. In addition, we report for the first time that as many as one-third of patients requiring hospital readmission post-TAVR are in fact hospitalized on multiple occasions (mean, 2.6 ± 1.0) within the year after TAVR. This represents a significant readmission burden, much higher than those observed in previous studies involving cardiac interventions (17) and close to those observed after heart failure hospitalizations (18,19). The additional costs associated with such a high rehospitalization rate may lead some to question the cost-effectiveness of TAVR in an all-comers setting. These data suggest the need to better define risk factors associated with post-TAVR readmissions to implement appropriate preventive strategies.
Causes of hospital readmission post-TAVR
The reasons for repeat hospitalization after TAVR were diverse and included a broad of range of cardiac and noncardiac etiologies. Noncardiac causes represented the main reason for hospital readmissions in ∼60% of patients, and respiratory, infection, and bleeding-related events accounted for approximately one-half of such readmissions. These rates mimic those reported for mortality causes in TAVR patients (20–23) and highlight the importance of comorbid conditions in this population. Pneumonia has been described as the most frequent cause of noncardiac readmission after hospital discharge (1) and was also the most common noncardiac cause for hospital readmission in the present analysis. Other infections, predominantly access site and genitourinary, were also frequent. Special attention to proven strategies for reducing respiratory and access-site infections may be critical to improve readmission rates (24,25). Furthermore, bleeding (mostly gastrointestinal) and vascular events were important factors related to hospital readmission. It has been shown that major late bleeding events are a strong predictor of late mortality after TAVR and increase the risk of rehospitalization (26). This underscores the difficulties in selecting the most appropriate antithrombotic treatment in this elderly and high-risk population, emphasizing the cautionary use of overly aggressive antithrombotic regimens (27). Finally, although readmissions due to traumatic causes were relatively infrequent, post-discharge rehabilitation programs to improve physical fitness and avoid falls and fractures in this frail population may be of the utmost importance as a preventive strategy as well as for improving patients’ quality of life.
Approximately 40% of unplanned hospital readmissions after TAVR were due to cardiac causes, and heart failure accounted for more than one-half of such rehospitalizations. Importantly, a significant proportion of such readmissions occurred within the 30 days after hospital discharge. Although only one-fifth of patients undergoing TAVR have a reduced left ventricular ejection fraction, heart failure remains the most important single cause of mortality and rehospitalization among TAVR patients (22,28). A higher left ventricular mass regression post-TAVR has been reported as an independent factor of late rehospitalizations due to heart failure (8). This suggests an important role for diastolic dysfunction in such patients and underscores the importance of intervening before excessive ventricular hypertrophy and advanced fibrosis occurs. It has been shown that the vast majority of patients undergoing TAVR have elevated N-terminal pro–B-type natriuretic peptide levels irrespective of ventricular function parameters (29). Also, the high prevalence of comorbidities such as hypertension, anemia, renal dysfunction, atrial fibrillation, and concomitant significant mitral regurgitation may also contribute to the high rate of heart failure rehospitalization after TAVR. Although we did not find an association between significant post-TAVR aortic regurgitation, this factor has been reported to increase N-terminal pro–B-type natriuretic peptide levels and rehospitalization due to heart failure in previous studies (8,30). This highlights the critical role of implementing post-TAVR programs with closer follow-up similar to those used for heart failure patients to reduce the rehospitalization burden (31,32). Meanwhile, the involvement of the already well-established heart failure clinics may represent a very first measure to improve outcomes in these patients.
Cardiac arrhythmias are a well-known factor for rehospitalization after cardiac surgery (13,33), representing the second cause of cardiac readmissions after TAVR in the present study. Interestingly, tachyarrhythmias (mainly atrial fibrillation) accounted for two-thirds of such cases, whereas bradyarrhythmias were responsible for one-third of readmissions due to arrhythmic causes. These data suggest the extension of the atrial arrhythmia burden beyond the periprocedural period (34), and emphasize the importance of better establishing the predictors of late advanced atrioventricular block requiring pacemaker implantation after TAVR, especially in patients in whom conduction disturbances develop after the procedure (28,35,36). Importantly, although one-fourth of cardiac readmissions required an invasive procedure (mainly pacemaker implantation or coronary angiography), only a few patients required reintervention at the prosthesis level (balloon post-dilation, paravalvular leak closure, or implantation of a second valve in most cases). This is in accordance with previous studies showing the very low rate of reinterventions or structural failure associated with transcatheter prostheses up to 5-year follow-up (37).
Predictors of 30-day and late hospital readmission post-TAVR
The ability to identify those patients at higher risk of readmission after TAVR is a critical step for optimizing health care programs in a cost-efficient manner. Interestingly, the predictors of 30-day readmission were mainly related to periprocedural complications (bleeding events in particular) and treatment at hospital discharge, whereas the main factors associated with later rehospitalizations were patient comorbidities.
Periprocedural major bleeding events remain one of the most frequent complications of TAVR, and several studies have shown the high impact of such events on patient survival (26,27,38). It is therefore not surprising that this periprocedural complication predicted early readmissions in our study. Additionally, a lower hemoglobin level at hospital discharge also played an important role in early readmissions. In fact, anemia has been well recognized as an important risk factor for hospital readmission (39), and we previously showed that the vast majority of TAVR patients have some degree of anemia at hospital discharge (40). The interaction between low hemoglobin levels and heart failure decompensation as well as enhancement of the symptoms related to any bleeding episode may represent the most important pathophysiological links between anemia and early rehospitalization post-TAVR (41,42). Finally, a more intensive antithrombotic treatment consisting of a combination of anticoagulant and antiplatelet drugs was also associated with a higher risk of early readmissions. The use of such antithrombotic combination therapies has increased the risk of bleeding events after valve surgery, and its risks should be appropriately balanced against the potential benefits in this high-risk population (27). In summary, these results suggest that reducing periprocedural bleeding events, better management of anemia before hospital discharge, and decreasing the intensity of antithrombotic treatment (particularly in patients with high bleeding risks) may reduce the rates of early rehospitalization after TAVR. The efficacy of implementing programs directed at correcting such factors needs to be demonstrated in future studies.
The risk of late (>30 days) readmission after TAVR was mainly determined by the presence of atrial fibrillation, peripheral vascular disease, chronic kidney disease, and chronic obstructive pulmonary disease, which have also been systematically found to be strong mortality risk factors in TAVR (6,22,23). Lindman et al. (8) also reported an independent association between major arrhythmia and late procedure-related or cardiac readmission. Interestingly, a lower mean gradient at baseline was a factor determining multiple readmissions in our study. Multidisciplinary evaluation of these patients is necessary not only in the patient-selection process, but also in post-procedure follow-up. These findings suggest that implication and evaluation in the immediate outpatient TAVR clinic by other specialized clinics (e.g., pulmonology, nephrology, geriatricians) will be essential to improve their outcomes. The complexity of the comorbidities of the current TAVR population may require a better selection process and closer follow-up.
Clinical impact of early readmissions post-TAVR
Previous studies in the surgical field have identified early readmission as a risk factor for mortality at follow-up (43). Similar to these studies, our results also suggest an independent association between early readmission post-TAVR and poorer clinical outcomes. Apart from the negative consequences of hospitalization (e.g., risk of nosocomial infections), early readmission probably identifies a vulnerable group of patients with a higher risk of poorer outcomes in the coming months. Future efforts should be made to identify and enhance the post-discharge health care measures in this group of patients.
This study was limited to 2 high-volume TAVR centers, and the results will need validation in a larger multicenter cohort of patients. However, readmission rates were similar to those recently reported in the TVT registry (6) and are likely representative of the global TAVR population. No event adjudication committee was available for this study. However, unlike most previous series reporting readmission rates on the basis of digital codes, the principal diagnosis for hospital readmission in our study was established on the basis of the final diagnosis at hospital discharge after a detailed medical record review. There was no systematic pre-procedural geriatric evaluation of the patients, and the impact of typical factors on this population such as frailty or cognitive impairment was not assessed.
The readmission burden in TAVR patients is very high (almost 50% at 1 year), with almost one-fourth of the episodes occurring in the early (≤30 days) period after hospital discharge. Noncardiac causes led by respiratory, infection, and bleeding events accounted for nearly two-thirds of readmission episodes, whereas cardiac causes led by heart failure were responsible for the remainder of hospitalizations. Although periprocedural bleeding events, left ventricular ejection fraction, anemia, and intensive antithrombotic treatment were the main predictors of early readmissions, patient comorbidities (chronic obstructive pulmonary disease, peripheral vascular disease, atrial fibrillation, and renal dysfunction) were the main factors determining late readmissions. Early readmission was identified as an independent predictor of mortality at 2-year follow-up. These results delineate, for the first time, all types of readmission causes post-TAVR and reflect the real-world all-comer readmission burden in this population. In addition, they provide the rationale for implementing specific health care programs to reduce readmissions after TAVR. While waiting for the results of future randomized studies to determine the most effective strategies to reduce hospital readmission and associated costs, urgent measures are needed to reduce such a high readmission burden and maintain the cost-effectiveness of TAVR.
WHAT IS KNOWN? Unplanned readmissions after initial cardiac intervention or hospitalization are frequent and associated with a significant impact on survival, patient quality of life, and health care costs.
WHAT IS NEW? Almost one-half of the patients undergoing TAVR were readmitted within 1 year. One-fifth were readmitted within the first month and multiple (≥2) readmissions were observed in more than one-third of the cohort. Approximately 60% of readmissions were secondary to noncardiac causes, and baseline comorbidities played an important role in delayed readmission.
WHAT IS NEXT? The high readmission burden observed in this population should be taken into account so that specific preventive measures and post-procedural management to reduce readmission rates and costs and improve quality of life after TAVR can be implemented.
Dr. Rodés-Cabau has received research grants from Edwards Lifesciences, Inc., St. Jude Medical, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- confidence interval
- hazard ratio
- interquartile range
- transcatheter aortic valve replacement
- Received July 22, 2015.
- Accepted July 30, 2015.
- American College of Cardiology Foundation
- Lindman B.R.,
- Stewart W.J.,
- Pibarot P.,
- et al.
- Kappetein A.P.,
- Head S.J.,
- Genereux P.,
- et al.,
- Valve Academic Research Consortium (VARC)-2
- Prentice R.L.,
- Williams B.J.,
- Peterson A.V.
- Curtis J.P.,
- Schreiner G.,
- Wang Y.,
- et al.
- Wasfy J.H.,
- Strom J.B.,
- O'Brien C.,
- et al.
- Shahian D.M.,
- He X.,
- O'Brien S.M.,
- et al.
- Rodés-Cabau J.,
- Webb J.G.,
- Cheung A.,
- et al.
- Ludman P.F.,
- Moat N.,
- de Belder M.A.,
- et al.
- Genereux P.,
- Cohen D.J.,
- Williams M.R.,
- et al.
- Rodes-Cabau J.,
- Dauerman H.L.,
- Cohen M.G.,
- et al.
- Urena M.,
- Webb J.G.,
- Eltchaninoff H.,
- et al.
- Sinning J.M.,
- Hammerstingl C.,
- Vasa-Nicotera M.,
- et al.
- Aranki S.F.,
- Shaw D.P.,
- Adams D.H.,
- et al.
- Amat-Santos I.J.,
- Rodés-Cabau J.,
- Urena M.,
- et al.
- Nazif T.M.,
- Williams M.R.,
- Hahn R.T.,
- et al.
- Urena M.,
- Webb J.G.,
- Cheema A.,
- et al.
- Borz B.,
- Durand E.,
- Godin M.,
- et al.
- Hannan E.L.,
- Zhong Y.,
- Lahey S.J.,
- et al.