Abstract
OBJECTIVES
The aim of this study was to validate recently proposed risk scores for the prediction of mortality up to 1 year after transcatheter aortic valve implantation (TAVI), using a self-expandable valve (CoreValve).
METHODS
In this single-centre study, 225 consecutive patients with severe symptomatic aortic valve stenosis, who underwent TAVI between December 2007 and January 2015, were included. Conventional surgical risk scores (logistic EuroSCORE, EuroSCORE II and STS score) were calculated as well as newly proposed TAVI risk scores (TAVI2-SCORe, STT Score and OBSERVANT score). Medium-term survival of the patients was assessed up to 1 year after TAVI.
RESULTS
The median age was 82 (77–86) years and 45.3% were male. Patients were categorized into ‘non-high risk’ or ‘high risk’ according to logistic EuroSCORE >20%, EuroSCORE II >8%, STS score >10%, TAVI2-SCORe >2, STT score >12% and OBSERVANT score >6. Thirty-day and 1-year survival rates were significantly different between ‘non-high-risk’ and ‘high-risk’ patients according to the STS score (1 year: low: 84.4% vs high: 67.0%, P = 0.010) and according to OBSERVANT score (1 year: low: 85.2% vs high: 68.4%, P = 0.005). In contrast, TAVI2-SCORe and STT score did not discriminate ‘non-high-risk’ and ‘high-risk’ patients. This was confirmed by Cox regression analysis [STS score >10%: hazard ratio: 2.484 (1.206–5.115), P = 0.014; OBSERVANT score >6: hazard ratio: 2.532 (1.295–4.952), P = 0.007].
CONCLUSIONS
In this single-centre study, OBSERVANT and STS score most accurately predicted early and mid-term survival in patients undergoing TAVI, using a self-expandable valve (CoreValve).
Keywords: Aortic valve stenosis, Transcatheter aortic valve implantation, Risk scores
INTRODUCTION
Recently, transcatheter aortic valve implantation (TAVI) has been proved to be a reasonable alternative for the treatment of severe, symptomatic aortic stenosis in ‘high-risk’ patients, not considered for surgical valve replacement [1–3]. According to the guidelines, patient selection for TAVI relies on the multidisciplinary heart team, evaluating technical aspects of the procedure, as well as the procedural risk of the patient. As already reported before, surgical risk scores [logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE), EuroSCORE II and Society of Thoracic Surgeons (STS) score] could be helpful, but are limited for these purposes [4–9]. Recently, new risk scores have been developed, specifically for patients suffering from severe, symptomatic aortic valve stenosis undergoing TAVI. The TAVI2-SCORe [10], the Survival posT TAVI (STT) score [11] and the Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis (OBSERVANT) score [12] have all been derived from baseline parameters (see Supplementary Table 1) and have all been outperforming conventional surgical risk scores for prediction of mortality after TAVI. The aim of this study was to validate these recently proposed risk scores for the prediction of mortality up to 1 year after TAVI.
METHODS
In this single-centre study, we included consecutive patients with severe symptomatic aortic valve stenosis, refused for surgical aortic valve replacement as decided by the local heart team, who underwent TAVI using the Medtronic CoreValve prosthesis between December 2007 and January 2015.
Baseline patient demographic data, cardiovascular risk factors, symptoms, quantification of aortic valve severity, medication and laboratory variables were collected.
Variables included in the conventional risk scores were previously described [13]. They were calculated using web-based systems [14–16]. Newly proposed TAVI risk scores (TAVI2-SCORe, STT score and the OBSERVANT score) were calculated for each patient. The STT score was calculated using the online application [17]. Patients were categorized ‘high risk’ or ‘non-high risk’ according to a logistic EuroSCORE of >20%, a EuroSCORE II of >8%, an STS score of >10%, a TAVI2-SCORe of >2, an STT score of >12% and an OBSERVANT score of >6 [10–12, 18].
Major adverse cardiac and cerebrovascular events (MACCEs) that occurred within 30 days after the procedure were reported according to the standardized endpoints of the Valve Academic Research Consortium 2 [19]. Medium-term survival of the patients was assessed up to 1 year after TAVI.
Statistical analysis
According to the distribution of the data (evaluated by histograms, QQ-plots and Kolmogorov–Smirnov test), continuous variables are presented as mean ± standard deviation (SD) or as median (Q1–Q3) and tested with Student's t-test or the Mann–Whitney U-test. Categorical variables are presented as n (%) and were tested with the Pearson χ2 or Fisher's exact test (when at least one cell of the cross tabs had an expected count of less than 5). A contingency analysis by kappa values was performed to assess the agreement of ‘non-high-risk’ and ‘high-risk’ classification between different risk scores. Kaplan–Meier curves were constructed to evaluate survival, and differences between the groups of risk scores were tested based on the log-rank test. Cox regression analysis determined predictors of mortality. Statistical analyses were conducted with SPSS version 20.0 (IBM Corporation, New York, USA).
RESULTS
Two hundred and twenty-five consecutive patients were included in this study. The median age was 82 (77–86) years old, 45.3% (n = 102) were male and the mean body mass index was 26.9 ± 4.8 kg/m2. They were all suffering from severe, symptomatic aortic valve stenosis, based on significantly reduced aortic valve area (0.64 ± 0.18 cm2), with a mean and peak gradient of 44 ± 15 and 69 ± 25 mmHg, respectively. The median left ventricular ejection fraction was 60 (50–62)%. Different comorbidities were present: 21.3% of the patients had diabetes (n = 48), 17.8% chronic obstructive pulmonary disease (n = 40) and 63.1% hypertension (n = 142). Previous procedures, such as percutaneous coronary intervention, coronary artery bypass grafting and valve surgery, were done in, respectively, 62 (27.6%), 68 (30.2%) and 10 (4.4%) patients. Of the total, 15.6% of the patients (n = 35) had a previous myocardial infarction and 7.1% (n = 16) had a permanent pacemaker at baseline. Median logistic EuroSCORE, EuroSCORE II and STS score were 15.3 (10.1–23.5), 5.1 (2.9–8.8) and 6.3 (5.6–8.2)%, respectively. The different parameters composing the new risk scores are described in Table 1, together with their prevalence.
Table 1:
Description of the different parameters of the new risk scores
| TAVI2-SCORe | |
| Porcelain aorta [1 point] | 22 (9.8) |
| Anaemia: haemoglobin <10 g/dl [1 point] | 11 (4.9) |
| Left ventricular dysfunction: left ventricular ejection fraction <35% [1 point] | 10 (4.4) |
| Recent myocardial infarction: <90 days before TAVI [2 points] | 5 (2.2) |
| Male sex category [1 point] | 102 (45.3) |
| Critical aortic valve stenosis: mean aortic valve gradient ≥70 mmHg [1 point] | 18 (8.0) |
| Old age: >85 years [1 point] | 64 (28.4) |
| Renal dysfunction: creatinine clearance <30/kg/min [1 point] | 18 (8.0) |
| Survival posT TAVI score | |
| Glomerular filtration rate (ml/min/1.73 m2) | 58.6 ± 21.0 |
| Systolic pulmonary arterial pressure >50 mmHg | 47 (20.9) |
| Previous stroke | 22 (9.8) |
| OBSERVANT score | |
| Glomerular filtration rate <45 ml/min [6 points] | 60 (26.7) |
| Critical state [5 points] | 0 (0.0) |
| Pulmonary hypertension: systolic pulmonary arterial pressure >60 mmHg [4 points] | 22 (9.8) |
| Diabetes mellitus [4 points] | 50 (22.2) |
| New York Heart Association class 4 [4 points] | 31 (13.8) |
| Prior balloon aortic valvuloplasty [3 points] | 12 (5.3) |
| Left ventricular dysfunction: left ventricular ejection fraction <40% [3 points] | 20 (8.9) |
Data are presented as n (%) of mean ± standard deviation.
TAVI: transcatheter aortic valve implantation; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
Figure 1A describes the categorization of the TAVI patients as ‘non-high risk’ or ‘high risk’ according to the different risk scores. Agreement between these risk scores to categorize patients as ‘non-high-risk’ and ‘high-risk’ is visualized in Fig. 1B. The agreement between logistic EuroSCORE and EuroSCORE II was the strongest (kappa = 0.642, P = 0.001). The OBSERVANT score agreed with EuroSCORE II (kappa: 0.143, P = 0.027) and STS score (kappa: 0.245, P = <0.001). The number of similarly classified patients was the lowest in logistic EuroSCORE and the STT score (n = 140; kappa = −0.074, P = 0.155).
Figure 1:
(A) Categorization of the TAVI patients in ‘non-high risk’ or ‘high risk’ according to risk scores. Logistic EuroSCORE: ≤20, >20%; EuroSCORE II: ≤8, >8%; Society of Thoracic Surgeons (STS) score: ≤10, >10%; TAVI2-SCORe ≤2, >2; Survival posT TAVI (STT) score: ≤12, >12%; and OBSERVANT score: ≤6, >6. Numbers represent the patients in that group. (B) Agreement between the different risk scores in the categorization of TAVI patients. TAVI: transcatheter aortic valve implantation; EuroSCORE: European System for Cardiac Operative Risk Evaluation; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
The incidence of procedure-related MACCEs according to the risk scores is summarized in Tables 2 and 3. Procedural mortality occurred in 6 patients, 30-day mortality in 17 patients and 1-year mortality in 38 patients. Logistic EuroSCORE and EuroSCORE II categorized most patients who died during the procedure as high risk. Most patients who died during 30 days and 1 year after TAVI were categorized as high risk according to the logistic EuroSCORE and the OBSERVANT score (Fig. 2). In Fig. 3, Kaplan–Meier curves represent mortality during 1 year after TAVI, according to the different risk scores. Survival between the ‘non-high risk’ and the ‘high-risk’ group of the STS score and the OBSERVANT score was significantly different, based on the log-rank test. Furthermore, Cox regression analysis confirmed these results (Table 4). Using three risk groups (low—moderate—high) according to the STS and the OBSERVANT score, a stepwise increase in mortality was seen according to the OBSERVANT score (Fig. 4).
Table 2:
Major adverse cardiovascular and cerebral events (MACCEs) within 30 days after the procedure, according to logistic EuroSCORE, EuroSCORE II and STS score
| Logistic EuroSCORE |
EuroSCORE II |
STS score |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| ≤20% | >20% | ≤8% | >8% | ≤10% | >10% | ||||
| MACCEs | |||||||||
| Stroke or transient ischemic attack | 8 (5.2) | 1 (1.4) | 0.279 | 6 (3.8) | 3 (4.6) | 0.720d | 8 (4.1) | 1 (3.2) | 1.000d |
| Life-threatening bleeding | 4 (2.6) | 4 (5.6) | 0.265d | 6 (3.8) | 2 (3.1) | 1.000d | 6 (3.1) | 2 (6.5) | 0.304d |
| Major bleeding | 10 (6.5) | 5 (7.0) | 1.000d | 10 (6.3) | 5 (7.7) | 0.769d | 11 (5.7) | 4 (12.9) | 0.134d |
| Minor bleeding | 25 (16.2) | 14 (19.7) | 0.521 | 26 (16.3) | 13 (20.0) | 0.501 | 33 (17.0) | 6 (19.4) | 0.749 |
| Major vascular complications | 3 (1.9) | 4 (5.6) | 0.211d | 3 (1.9) | 4 (6.2) | 0.109d | 5 (2.6) | 2 (6.5) | 0.248d |
| Minor vascular complications | 46 (29.9) | 18 (25.4) | 0.485 | 47 (29.4) | 17 (26.2) | 0.627 | 56 (28.9) | 8 (25.8) | 0.726 |
| Aortic regurgitation grade II–IVa | 31 (23.7) | 12 (21.4) | 0.739 | 33 (24.6) | 10 (18.9) | 0.399 | 37 (22.8) | 6 (24.0) | 0.898 |
| New pacemakerb | 42 (29.2) | 26 (40.0) | 0.122 | 50 (33.8) | 18 (29.5) | 0.549 | 57 (31.8) | 11 (36.7) | 0.602 |
| Survival | |||||||||
| Procedural success | 152 (98.7) | 67 (94.4) | 0.081d | 158 (98.8) | 61 (93.8) | 0.059d | 190 (97.9) | 29 (93.5) | 0.194d |
| Alive 30 days post-TAVI | 145 (94.2) | 63 (88.7) | 0.153 | 150 (93.8) | 58 (89.2) | 0.270d | 183 (94.3) | 25 (80.6) | 0.017d |
| Alive 1 year post-TAVIc | 101 (80.2) | 53 (80.3) | 0.981 | 105 (79.5) | 49 (81.7) | 0.732 | 135 (82.8) | 19 (65.5) | 0.031 |
EuroSCORE: European System for Cardiac Operative Risk Evaluation; STS: Society of Thoracic Surgeon; TAVI: transcatheter aortic valve implantation.
an = 187, bn = 209, cn = 192, dFisher's Exact Test.
Table 3:
Major adverse cardiovascular and cerebral events (MACCEs) within 30 days after the procedure, according to TAVI2-SCORe, survival posT TAVI score and OBSERVANT score
| TAVI2-SCORe |
Survival posT TAVI score |
OBSERVANT score |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| ≤2 | >2 | ≤12% | >12% | ≤6 | >6 | ||||
| MACCEs | |||||||||
| Stroke or transient ischemic attack | 9 (4.3) | 0 (0.0) | 1.000d | 8 (3.9) | 1 (4.5) | 1.000d | 8 (4.4) | 1 (2.2) | 0.691d |
| Life-threatening bleeding | 8 (3.9) | 0 (0.0) | 1.000d | 8 (3.9) | 0 (0.0) | 1.000d | 7 (3.9) | 1 (2.2) | 1.000d |
| Major bleeding | 14 (6.8) | 1 (5.6) | 1.000d | 15 (7.4) | 0 (0.0) | 0.372d | 12 (6.7) | 3 (6.7) | 1.000d |
| Minor bleeding | 35 (16.9) | 4 (22.2) | 0.525d | 33 (16.3) | 6 (27.3) | 0.232d | 27 (15.0) | 12 (26.7) | 0.064 |
| Major vascular complications | 6 (2.9) | 1 (5.6) | 0.447d | 6 (3.0) | 1 (4.5) | 0.518d | 4 (2.2) | 3 (6.7) | 0.145d |
| Minor vascular complications | 62 (30.0) | 2 (11.1) | 0.089 | 57 (28.1) | 7 (31.8) | 0.712 | 55 (30.6) | 9 (20.0) | 0.160 |
| Aortic regurgitation grade II–IVa | 36 (21.1) | 7 (43.8) | 0.058d | 39 (23.4) | 4 (20.0) | 1.000d | 34 (23.1) | 9 (22.5) | 0.933 |
| New pacemakerb | 60 (31.3) | 8 (47.1) | 0.182 | 60 (31.4) | 8 (44.4) | 0.259 | 50 (30.1) | 18 (41.9) | 0.143 |
| Survival | |||||||||
| Procedural success | 202 (97.6) | 17 (94.4) | 0.397d | 198 (97.5) | 21 (95.5) | 0.465d | 176 (97.8) | 43 (95.6) | 0.345d |
| Alive 30 days post-TAVI | 192 (92.8) | 16 (88.9) | 0.633d | 187 (92.1) | 21 (95.5) | 1.000d | 171 (95.0) | 37 (82.2) | 0.008d |
| Alive 1 year post-TAVIc | 142 (80.7) | 12 (75.0) | 0.527d | 141 (80.6) | 13 (76.5) | 0.750d | 127 (83.6) | 27 (67.5) | 0.023 |
TAVI: transcatheter aortic valve implantation; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
an = 187, bn = 209, cn = 192, dFisher's Exact Test.
Figure 2:
Categorization of the patients deceased during the procedure (left panel), during 30 days after TAVI (middle panel) and during the 1-year follow-up (right panel) in the ‘non-high-risk’ or ‘high-risk’ group. Numbers represent the patients in that group. STS: Society of Thoracic Surgeons; TAVI: transcatheter aortic valve implantation; EuroSCORE: European System for Cardiac Operative Risk Evaluation; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
Figure 3:
Kaplan–Meier survival curves according to the risk score. STS: Society of Thoracic Surgeons; EuroSCORE: European System for Cardiac Operative Risk Evaluation; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
Table 4:
Predictors of mortality up to 1 year after TAVI
| Cox regression | Thirty days |
One year |
||||||
|---|---|---|---|---|---|---|---|---|
| Hazard ratio | 95% CI |
P-value | Hazard ratio | 95% CI |
P-value | |||
| Lower | Upper | Lower | Upper | |||||
| Logistic EuroSCORE (%) | 1.016 | 0.981 | 1.053 | 0.364 | 1.001 | 0.975 | 1.028 | 0.930 |
| Logistic EuroSCORE >20% | 1.964 | 0.758 | 5.090 | 0.165 | 1.107 | 0.566 | 2.165 | 0.766 |
| EuroSCORE II (%) | 1.061 | 0.997 | 1.129 | 0.060 | 1.034 | 0.984 | 1.086 | 0.190 |
| EuroSCORE II >8% | 1.756 | 0.668 | 4.614 | 0.253 | 0.979 | 0.485 | 1.973 | 0.952 |
| STS score (%) | 1.118 | 1.018 | 1.228 | 0.020 | 1.108 | 1.036 | 1.185 | 0.003 |
| STS score >10% | 3.555 | 1.315 | 9.614 | 0.012 | 2.484 | 1.206 | 5.115 | 0.014 |
| TAVI2-SCORe | 0.913 | 0.544 | 1.532 | 0.729 | 0.959 | 0.684 | 1.346 | 0.810 |
| TAVI2-SCORe >2 | 1.596 | 0.365 | 6.977 | 0.535 | 1.411 | 0.501 | 3.978 | 0.514 |
| posT TAVI score (%) | 0.991 | 0.905 | 1.085 | 0.841 | 1.021 | 0.998 | 1.045 | 0.075 |
| posT TAVI score >12% | 0.573 | 0.076 | 4.318 | 0.589 | 1.109 | 0.393 | 3.125 | 0.845 |
| OBSERVANT score | 1.155 | 1.046 | 1.275 | 0.004 | 1.095 | 1.020 | 1.175 | 0.012 |
| OBSERVANT score >6 | 3.743 | 1.444 | 9.704 | 0.007 | 2.356 | 1.205 | 4.607 | 0.012 |
TAVI: transcatheter aortic valve implantation; EuroSCORE: European System for Cardiac Operative Risk Evaluation; STS: Society of Thoracic Surgeon; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
Figure 4:
Kaplan–Meier survival curves of low-, moderate- and high-risk patients according to Society of Thoracic Surgeons (STS) and OBSERVANT score. TAVI: transcatheter aortic valve implantation; OBSERVANT: Observational Study of Appropriateness, Efficacy And Effectiveness of AVR-TAVR Procedures For the Treatment Of Severe Symptomatic Aortic Stenosis.
DISCUSSION
This study is, to the best of our knowledge, the first to compare the six available risk scores in patients with severe, symptomatic aortic valve stenosis. The three conventional surgical risk scores (logistic EuroSCORE, EuroSCORE II and STS score) correlated the most to each other. The OBSERVANT score agreed with EuroSCORE II and STS score. A higher TAVI2-SCORe was related to higher incidence of significant aortic regurgitation post-TAVI and a higher OBSERVANT score was related to more minor bleeding events post-TAVI. A higher logistic EuroSCORE and EuroSCORE II were related to higher procedural mortality, whereas a higher STS score and OBSERVANT score were related to 30-day and 1-year mortality.
As mentioned by Debonnaire et al. [10], TAVI risk scores should predict 30-day, as well as 1-year mortality post-TAVI in order to allow proper risk assessment and optimal patient selection, together with evaluation of cost–benefits for a given treatment. Due to the unavailability of TAVI-specific risk scores, conventional surgical risk scores were used for this purpose. Of the three conventional risk scores, only the STS score could significantly discriminate patients with good and limited mid-term prognosis in this patient cohort. Nevertheless, the STS score was not developed for TAVI and calculation of the STS score is time-consuming, involving more than 40 parameters that need to be available. Therefore, the development of specific TAVI risk scores remains of valuable importance.
Recently, three risk tools were proposed as specific TAVI risk scores.
The TAVI2-SCORe was developed in patients who underwent TAVI with the Edwards SAPIEN system at the Leiden University Medical Center (Leiden, Netherlands; n = 207) and Centro Cardiologico Monzino IRCCS (Milan, Italy; n = 304) between November 2007 and November 2012 (n = 511) [10]. Mortality within 30 days occurred in 29 patients (29 of 511, 5.7%), and within 1 year in 80 patients (80 of 471, 17.0%). In contrast to our data, 1-year survival was not significantly different between low- and high-risk patients according to the STS score. We assume that this might be partly explained by a remarkably high percentage of high-risk patients according to the STS score of >10% (90% of their cohort) in comparison with our data (14% in the present study).
Porcelain aorta and anaemia are two parameters representing more TAVI-specific risk factors, not included in the conventional risk scores. In their study cohort, 12% of patients had an elevated risk (TAVI2-SCORe >2), and 1-year survival was significantly different between the two groups of patients (TAVI2-SCORe ≤2: 88% vs TAVI2-SCORe >2: 54%; P < 0.001). In comparison with our study, less patients (8%) were at high risk and the TAVI2-SCORe could not differentiate patients with good and bad prognosis at 30 days, nor at 1 year post-TAVI. The TAVI2-SCORe was developed in patients undergoing TAVI with the Edwards SAPIEN system. In our patient cohort, the Medtronic CoreValve system was used. Therefore, the predictive value of the TAVI2-SCORe might not be extrapolated to our patient population.
The STT score was derived from baseline characteristics of patients who underwent TAVI with the Edwards SAPIEN system or the Medtronic CoreValve system at six institutions (Turin, Catania, Padova, two centres in Milan and Utrecht) [11]. The STT score was externally validated in an independent cohort of Bologna. All patients were treated between January 2007 and December 2012. Mortality within 30 days occurred in, respectively, 60 patients (60 of 1067, 5.6%) and 13 patients (13 of 177, 7.3%), and within 1 year in, respectively, 165 patients (165 of 1067, 15.4%) and in 63 patients (63 of 177, 35.6%). No differences were found in the logistic EuroSCORE and the STS score between patients who survived and patients who died within 1 year post-TAVI. No Kaplan–Meier curves were included in the manuscript to compare survival between low- and high-risk patients. In our study, the STT score could neither differentiate patients with good and bad prognosis at 30 days, nor at 1 year post-TAVI.
The OBSERVANT score was derived from baseline characteristics of patients who underwent TAVI with the Edwards SAPIEN system or the Medtronic CoreValve system at 95 Italian institutions (n = 1256) [12]. The OBSERVANT score was externally validated on an independent cohort (n = 622). All patients were treated between December 2010 and June 2012. Mortality within 30 days occurred in, respectively, 77 patients (77 of 1256, 6.1%) and 37 patients (37 of 177, 5.9%). In their study cohort, 41.9% had an elevated risk. In comparison with our study, less patients (23.6%) were at high risk. The 30-day mortality was significantly different between the two groups of patients (OBSERVANT score ≤6: 2.4% vs OBSERVANT score >6: 11.4%; P < 0.001). This observation was confirmed in our study: OBSERVANT score ≤6: 5.0% vs OBSERVANT score >6: 17.8%; P = 0.008. Moreover, this risk estimation could be extrapolated to 1-year mortality (at least in our study cohort) and in contrast to the STS score, the OBSERVANT score showed a good stepwise increase in 30-day as well as in 1-year mortality, based on three risk groups. The fact that the OBSERVANT score, containing only seven parameters, was more significantly predictive than the time-consuming STS score favours its clinical applicability.
An important parameter, not included in any of these risk scores, but suggested in the literature to estimate the risk specifically in TAVI patients, is frailty [20, 21]. However, since there is no general definition of frailty available, further research is necessary in order to compose optimal criteria to evaluate frailty in aortic valve stenosis. Also, red cell distribution width gained interest in the risk estimation of TAVI patients [9, 22–23].
The discordances between survival of ‘high’-risk patients in various TAVI cohorts underline the need of validation in external large real-world populations before a new risk score should be used in everyday clinical practice. Ideally, this risk score is a simple and accurate tool that can be used both in patients treated with a balloon-expandable TAVI prosthesis as well as in patients treated with a self-expandable system.
Limitations of the study
This study was based on a single-centre population, including a limited number of patients and only one type of transcatheter aortic valve implanted (Medtronic CoreValve). Results can therefore not be extrapolated to other types of valves. Use of the CoreValve frame is indeed associated with typical problems, potentially influencing the final results of our study. Based on the results of the Belgian TAVI Registry [24] and the randomized CHOICE trial [25], comparing transfemoral TAVI with balloon-expandable vs self-expandable transcatheter valve, more patients develop significant aortic regurgitation and new conduction disturbances within 30 days after CoreValve implantation. Because aortic regurgitation post-TAVI is a predictor of mortality, this could potentially bias the results. Nevertheless, according to the survival curves reported in both studies, no differences in mortality between patients implanted with balloon-expandable and self-expandable valve were found.
Finally, grouping of the patients within the evaluated score systems is somewhat ‘author-dependent’. However, for our analysis, we respected the risk cohorts as published by the different authors, taking into account that the number in some of the patient subgroups were too limited for meaningful statistical analysis. Keeping this in mind, according to the actually available guidelines, TAVI has been proven to be a reasonable alternative for the treatment of severe, symptomatic aortic stenosis in ‘high-risk’ patients, we decided to focus primarily on ‘high-risk’ compared with ‘non-high-risk’ patients.
CONCLUSION
In this single-centre study, the OBSERVANT and STS score most accurately predicted early and mid-term survival in patients undergoing TAVI, using a self-expandable valve (CoreValve). However, further validation in large external patient cohorts using different valve frames is needed.
SUPPLEMENTARY MATERIAL
Supplementary material is available at ICVTS online.
Conflict of interest: Johan M. Bosmans is a part-time clinical proctor for Medtronic CoreValve.
REFERENCES
- 1.Kodali SK, Williams MR, Smith CR, Svensson LG, Webb JG, Makkar RR et al. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med 2012;366:1686–95. [DOI] [PubMed] [Google Scholar]
- 2.Makkar RR, Fontana GP, Jilaihawi H, Kapadia S, Pichard AD, Douglas PS et al. Transcatheter aortic-valve replacement for inoperable severe aortic stenosis. N Engl J Med 2012;366:1696–704. [DOI] [PubMed] [Google Scholar]
- 3.Linke A, Wenaweser P, Gerckens U, Tamburino C, Bosmans J, Bleiziffer S et al. Treatment of aortic stenosis with a self-expanding transcatheter valve: the InternationalMulti-centre ADVANCE Study. Eur Heart J 2014;35:2672–84. [DOI] [PubMed] [Google Scholar]
- 4.Roques F, Michel P, Goldstone AR, Nashef SA. The logistic EuroSCORE. Eur Heart J 2003;24:882–3. [DOI] [PubMed] [Google Scholar]
- 5.Nashef SA, Roques F, Sharples LD, Nilsson J, Smith C, Goldstone AR et al. EuroSCORE II. Eur J Cardiothorac Surg 2012;41:734–44. [DOI] [PubMed] [Google Scholar]
- 6.O'Brien SM, Shahian DM, Filardo G, Ferraris VA, Haan CK, Rich JB et al. The Society of Thoracic Surgeons 2008 Cardiac Surgery Risk Models: part 2—isolated valve surgery. Ann Thorac Surg 2009;88:S23–42. [DOI] [PubMed] [Google Scholar]
- 7.Watanabe Y, Hayashida K, Lefèvre T, Chevalier B, Hovasse T, Romano M et al. Is EuroSCORE II better than EuroSCORE in predicting mortality after transcatheter aortic valve implantation? Catheter Cardiovasc Interv 2013;81:1053–60. [DOI] [PubMed] [Google Scholar]
- 8.D'Ascenzo F, Ballocca F, Moretti C, Barbanti M, Gasparetto V, Mennuni M et al. Inaccuracy of available surgical risk scores to predict outcomes after transcatheter aortic valve replacement. J Cardiovasc Med 2013;14:894–8. [DOI] [PubMed] [Google Scholar]
- 9.Collas VM, Paelinck BP, Rodrigus IE, Vrints CJ, Van Craenenbroeck EM, Bosmans JM. Red cell distribution width improves the prediction of prognosis after transcatheter aortic valve implantation. Eur J Cardiothorac Surg 2015; doi:10.1093/ejcts/ezv152. [DOI] [PubMed] [Google Scholar]
- 10.Debonnaire P, Fusini L, Wolterbeek R, Kamperidis V, van Rosendael P, van der Kley F et al. Value of the ‘TAVI 2-SCORe’ versus surgical risk scores for prediction of one year mortality in 511 patients who underwent transcatheter aortic valve implantation. Am J Cardiol 2015;115:234–42. [DOI] [PubMed] [Google Scholar]
- 11.D'Ascenzo F, Capodanno D, Tarantini G, Nijhoff F, Ciuca C, Rossi M et al. Usefulness and validation of the survival posT TAVI score for survival after transcatheter aortic valve implantation for aortic stenosis. Am J Cardiol 2014;114:1867–74. [DOI] [PubMed] [Google Scholar]
- 12.Capodanno D, Barbanti M, Tamburino C, D'Errigo P, Ranucci M, Santoro G et al. A simple risk tool (the OBSERVANT score) for prediction of 30-day mortality after transcatheter aortic valve replacement. Am J Cardiol 2014;113:1851–8. [DOI] [PubMed] [Google Scholar]
- 13.Collas V, Chong YM, Rodrigus I, Vandewoude M, Bosmans J. Predictive mortality estimation in older patients undergoing TAVI—comparison of the logistic EuroSCORE, EuroSCORE II and STS-score. Eur Ger Med 2015;6:11–4. [Google Scholar]
- 14.European System for Cardiac Operative Risk Evaluation (Logistic EuroSCORE). Online Logistic EuroSCORE Calculator. http://www.euroscore.org/calcold.html (19 June 2015, date last accessed).
- 15.European System For Cardiac Operative Risk Evaluation (EuroSCORE II). Online EuroSCORE II Calculator. http://www.euroscore.org/calc.html (9 June 2015, date last accessed).
- 16.Society of Thoracic Surgeons. Online STS Risk Calculator. http://riskcalc.sts.org/stswebriskcalc/#/ (19 June 2015, date last accessed).
- 17.Survival posT TAVI Score. Online STT Risk Calculator. http://www.cardiogroup.org/taviscore/index.php?cat=home (19 June 2015, date last accessed).
- 18.Gilard M, Eltchaninoff H, Iung B, Donzeau-Gouge P, Chevreul K, Fajadat J et al. Registry of transcatheter aortic-valve implantation in high-risk patients. N Engl J Med 2012;366:1705–15. [DOI] [PubMed] [Google Scholar]
- 19.Kappetein AP, Head SJ, Généreux P, Piazza N, van Mieghem NM, Blackstone EH et al. Updated standardized endpoint definitions for transcatheter aortic valve implantation the valve academic research consortium-2 consensus document. J Am Coll Cardiol 2012;60:1438–54. [DOI] [PubMed] [Google Scholar]
- 20.Schoenenberger AW, Stortecky S, Neumann S, Moser A, Jüni P, Carrel T et al. Predictors of functional decline in elderly patients undergoing transcatheter aortic valve implantation (TAVI). Eur Heart J 2013;34:684–92. [DOI] [PubMed] [Google Scholar]
- 21.Kamga M, Boland B, Cornette P, Beeckmans M, De Meester C, Chenu P et al. Impact of frailty scores on outcome of octogenarian patients undergoing transcatheter aortic valve implantation. Acta Cardiol 2013;68:599–606. [DOI] [PubMed] [Google Scholar]
- 22.Aung N, Dworakowski R, Byrne J, Alcock E, Deshpande R, Rajagopal K et al. Progressive rise in red cell distribution width is associated with poor outcome after transcatheter aortic valve implantation. Heart 2013;99:1261–6. [DOI] [PubMed] [Google Scholar]
- 23.Magri CJ, Chieffo A, Latib A, Montorfano M, Maisano F, Ciono M et al. Red blood cell distribution width predicts one-year mortality following transcatheter aortic valve implantation. Int J Cardiol 2014;172:456–7. [DOI] [PubMed] [Google Scholar]
- 24.Collas VM, Dubois C, Legrand V, Kefer J, De Bruyne B, Dens J et al. Mid-term clinical outcome following Edwards SAPIEN or Medtronic Corevalve transcatheter aortic valve implantation (TAVI): results of the Belgian TAVI registry. Catheter Cardiovasc Interv 2015;86:528–35. [DOI] [PubMed] [Google Scholar]
- 25.Abdel-Wahab M, Neumann FJ, Mehilli J, Frerker C, Richardt D, Landt M et al. 1-year outcomes after transcatheter aortic valve replacement with balloon-expandable versus self-expandable valves: results from the CHOICE randomized clinical trial. J Am Coll Cardiol 2015;66:791–800. [DOI] [PubMed] [Google Scholar]
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