The application of the CHA 2 DS 2 -VAS C score as a novel risk stratification tool for predicting outcome in clinical applications other than atrial fibrillation and stroke prevention has been previously examined. However, its usefulness in a population of patients with coronary artery disease after percutaneous coronary intervention (PCI) has not been explored. We investigated 12,785 consecutive patients who underwent PCI in a tertiary medical center from April 2004 to August 2014 (mean follow-up 6.5 years) and computed the CHA 2 DS 2 -VAS C score on their index PCI. We assessed the relation between the CHA 2 DS 2 -VAS C score and clinical outcomes (for example, all-cause mortality and mortality or myocardial infarction) at 1 and 5 years. The mean CHA 2 DS 2 -VAS C score was 3.7 ± 1.7, 59.1% of patients obtained a score of 3 to 5. Both the primary and secondary outcomes at 1 and 5 years were significantly more frequent as the CHA 2 DS 2 -VAS C score increased. Overall, the mortality rate after PCI was 10 times higher for patients with a CHA 2 DS 2 -VAS C score of 5 compared with a score of 1 at both 1-and 5-year follow-up. The CHA 2 DS 2 -VAS C score predicted all-cause mortality and death or nonfatal myocardial infarction in a significant (p <0.001, C-index 0.73 and 0.72) and linear fashion. In conclusion, the CHA 2 DS 2 -VAS C score can be used as a simple and effective tool to predict long-term clinical outcomes in patients undergoing PCI.
Although risk scores, such as the Society of Thoracic Surgeons score and EuroSCORE to estimate the perioperative risk of complications from coronary artery bypass grafting and Synergy between percutaneous coronary intervention (PCI) with Taxus and Cardiac Surgery (SYNTAX) score to predict adverse ischemic events in patients undergoing PCI have been widely used, other risk score for the evaluation of clinical outcome after PCI (clinical SYNTAX, SYNTAX II, the National Cardiovascular Database Registry CathPCI, and the ACEF [age, creatinine, ejection fraction] model) are less widely used in clinical daily practice because of complex calculation, interobserver and intraobserver variability. Our aim was to investigate the predictive value of CHA 2 DS 2 -VAS C (congestive heart failure [CHF], hypertension, age ≥75 years, diabetes, previous stroke, vascular disease, age 65 to 74 years, gender [female] category) score as a simple tool for risk stratification of patients with PCI, regardless of atrial fibrillation (AF), in a large all-comer PCI cohort.
Methods
The study population comprised all consecutive patients (n = 12,785) who underwent PCI at our institution at the 2 hospitals of the Rabin Medical Center in Israel from April 2004 to August 2014. We computed the CHA 2 DS 2 -VAS C score on their index PCI (first PCI), regardless of having AF. Data collection was approved by the hospital ethics committee in compliance with the Declaration of Helsinki. As we have previously reported, all data regarding the index and subsequent procedures, as well as clinical and echocardiographic data, were extracted from the patients’ electronic medical records. Demographic data and death dates were obtained from the medical centers’ demographic information system, which is linked to the State of Israel Ministry of Interior data system and the Clalit Health Organization data warehouse. The accuracy of the mortality data was verified with the Israel Central Bureau of Statistics. All data regarding previous and subsequent hospitalizations, including all International Classification of Diseases, Ninth Revision , diagnoses, were retrieved from the medical centers’ data warehouse. Laboratory data were retrieved from the medical centers’ central laboratory database. All follow-up data were collected up to August 31, 2014.
Based on the CHA 2 DS 2 -VAS C score, patients were given 1 point for CHF, hypertension, age 65 to 74 years, diabetes mellitus, vascular disease, and female gender and 2 points for age 75 years or older and previous stroke. All patients had at least a score of 1 because all of them underwent PCI, thus, they suffered from vascular atherosclerosis.
We assessed the relation between CHA 2 DS 2 -VAS C score and clinical outcome which included all-cause mortality at 1-and 5-year follow-up as the primary end points and mortality or nonfatal myocardial infarction (MI) at 1-and 5-year follow-up as the secondary end points.
Baseline parameters were compared between groups using the Student t test for continuous variables and the chi-square test for categorical variables. Continuous variables were tested with the Kolmogorov–Smirnov test and found to have a normal distribution. The survival analysis was defined from the day of the index PCI. Survival curves were constructed using the Kaplan–Meier procedure with log-rank testing of significance. Survival tables were constructed using lifetable analysis. For the CHA 2 DS 2 -VAS C score’s predictive discrimination capability, a C-index was computed from Cox analysis using an adaptation of the method proposed by Pencina et al and of the programming algorithm of Liu et al. Statistical analyses were performed using IBM SPSS version 20 (IBM Corporation, Armonk, New York). All tests were 2-tailed, and p <0.05 was considered significant.
Results
A total of 12,785 patients (mean age 68.5 ± 12.2 years, 76.2% men) were evaluated for CHA 2 DS 2 -VAS C score at their index PCI. Most patients, 7,729 (60.5%), presented with acute coronary syndrome (ACS), of which 894 (11.6%) had ST elevation MI. Patients’ demographic, clinical, and angiographic features at the index PCI are listed in Table 1 . A previous diagnosis of AF was present in only 1,309 patients (10.2%).
| Variable | Total cohort (n=12,785) |
|---|---|
| Age (years) | 68.5±12.2 |
| Men | 76.2% |
| Diabetes mellitus | 43.1% |
| Hypertension | 73.2% |
| Smoker | 34.8% |
| Prior stroke | 5.6% |
| Prior atrial fibrillation | 10.2% |
| eGFR ( ml/min/1.73m 2 ) ∗ | 82.1± 27.3 |
| Creatinine (mg/dl) | 1.1±0.8 |
| Prior coronary bypass | 14.1% |
| Prior heart failure | 9.1% |
| Moderate/severe LV dysfunction | 12.6% |
| Clinical Presentation | |
| MI or ACS | 60.5% |
| ST-elevation MI | 7.0% |
| Stable angina pectoris | 39.5% |
| No. of coronary artery anomalies | |
| 1 | 23.4% |
| >2 | 43.4% |
| Single vessel PCI | 84.3% |
| Intervention in proximal vessel segment | 44.1% |
| Unprotected LM intervention | 2.1% |
| Drug eluting stent | 47.2% |
| Bare metal stent | 48.2% |
| Drug eluting balloon | 0.2% |
| Balloon angioplasty | 4.5% |
The mean CHA 2 DS 2 -VAS C score was 3.7 ± 1.7 (range 1 to 9). The CHA 2 DS 2 -VAS C score distribution at the index PCI is presented in Figure 1 . Most of the patients (59.1%) had a CHA 2 DS 2 -VAS C score of 3 to 5 with the most frequent score of 4 obtained in 2,762 patients (21.6%). The frequency of the CHA 2 DS 2 -VAS C score individual components are presented in Figure 2 .
The median follow-up time was 6.4 years (range 3.5 months to 10.6 years). Both the primary and secondary outcomes during follow-up increased linearly with elevated score ( Table 2 ). Overall, the mortality rate after PCI was 10 times greater for patients with a CHA 2 DS 2 -VAS C score of 5 compared with a score of 1 at both 1-and 5-year follow-up. The differences in clinical variables between patients with and without death and/or MI during follow-up are presented in Supplementary Table 1 .
| CHA 2 DS 2- VAS C score | All-cause mortality 1-year | All-cause mortality+ Non-fatal MI 1-year | All-cause mortality 5-years | All-cause mortality+ non-fatal MI 5-years |
|---|---|---|---|---|
| 1 | 1.0% | 2.1% | 2.5% | 4.3% |
| 2 | 2.4% | 3.8% | 4.3% | 7.4% |
| 3 | 3.7% | 5.1% | 8.9% | 11.6% |
| 4 | 6.1% | 7.8% | 17.4% | 20.4% |
| 5 | 10.7% | 13.3% | 25.9% | 29.8% |
| 6 | 12.5% | 16.6% | 33.1% | 37.4% |
| 7 | 15.2% | 20.1% | 39.4% | 45.3% |
| 8 | 22.2% | 27.8% | 53.5% | 57.2% |
| 9 | 19.2% | 34.6% | 39.5% | 51.0% |
The CHA 2 DS 2 -VAS C score predicted all-cause mortality and death or nonfatal MI in a significant (p <0.001) and linear fashion as shown in Figure 3 . The C-index measurements of the predictive power of the score were 0.73 (95% CI 0.7 to 0.76) for mortality and 0.72 (95% CI 0.69 to 0.75) for death or nonfatal MI. The proportional risk conferred by each point of the CHA 2 DS 2 -VAS C score was of 1.545 (95% CI 1.507 to 1.584), with a C-statistic of 0.73 (95% CI 0.7 to 0.76).
In a multivariate Cox adjusted model including CHA 2 DS 2 -VAS C and the clinical variables not included in the score, the performance of the CHA 2 DS 2 -VAS C score was maintained ( Supplementary Tables 2 and 3 ).
We compared the predictive ability of the CHA 2 DS 2 -VAS C score to the simple and available ACEF score (age/ejection fraction + 1 [if serum creatinine was >2.0 mg/dl]). We were able to calculate the ACEF score in 7,791 patients (61% of the cohort). When testing for prediction of all-cause mortality, the ACEF score was predictive, with a C-statistic of 0.65 (95% CI 0.61 to 0.69). Using a Cox analysis, the proportional risk conferred by each point of the ACEF score was of 3.134 (95% CI 2.85 to 3.442). We wanted to test whether the risk conferred by the ACEF score is incremental as in the CHA 2 DS 2 -VAS C score. We therefore classified the patients into 9 groups by the percentiles of the ACEF score and performed a Kaplan–Meier analysis ( Supplementary Figure 1). In the lower percentiles, the change in risk was not incremental although overall the score was predictive.
We performed a separate analysis according to the clinical presentation: patients with stable coronary versus ACS. The individual components of the CHA 2 DS 2 -VAS C score were compared between the patients with stable and ACS ( Table 3 ). The CHA 2 DS 2 -VAS C score predicted all-cause mortality and death or nonfatal MI in a significant (p <0.001) and graded manner for patients with both stable and ACS with a similar trend ( Figures 4 and 5 ).
| CHA 2 DS 2- VAS C componnts | Stable coronary patients (n=5056) | ACS patients (n=7729) | P value |
|---|---|---|---|
| CHF | 887 (17.5%) | 1606 (20.8%) | <0.001 |
| Hypertension | 3950 (78.1%) | 5439 (70.4%) | <0.001 |
| Age ≥75 years | 1915 (37.9%) | 2631 (34.0%) | <0.001 |
| Diabetes mellitus | 2385 (47.2%) | 3124 (40.4%) | <0.001 |
| Stroke | 236 (4.7%) | 483 (6.2%) | <0.001 |
| Age 65-74 years | 1521 (30.1%) | 1980 (25.6%) | <0.001 |
| Women | 1176 (23.3%) | 1865 (24.1%) | 0.26 |
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