ABC | Volume 113, Nº1, July 2019

Original Article Gil et al Risks scores in acute coronary syndromes Arq Bras Cardiol. 2019; 113(1):20-30 easily obtainable even in a pre-hospital setting). The score performed well in predicting in-hospital mortality, both in STEMI and NSTEMI (c-statistics ranging from 0.785 to 0.809). This risk score was formulated similarly to the C-ACS, a score formulated by a Canadian group and published in the American Heart Journal. The C-ACS developed a simple score with 4 variables (age ≥75, Killip class >I, systolic blood pressure < 100 mmHg and heart rate > 100 beats/min. 10 The score was derived from the Acute Myocardial Infarction in Quebec (AMI-QUEBEC) and Canada ACS-1 registries, compiling a total of 6,182 patients. 10 This score performed well at predicting worse outcome both in short-term (c-statistics ranging from 0.73 to 0.75) and in long-term mortality (c-statistics ranging from 0.73 to 0.76). 10 It was the authors´ objective to test several RS, which have been validated in the setting of ACS, to determine which one fared better at balancing a good predictive capability, combined with simple and intuitive use. The authors decided to apply the aforementioned RS in a single-centre population of patients admitted for ACS and compare each score to the ProACS. Risk scores and in-hospital mortality Almost all RS performed well. However, the CHA 2 DS 2 -VASc- HS and the C-ACS scores underperformed in this population (c-statistics of 0.600 and 0.619, respectively), even though both have been validated for the prediction of short-term mortality. The TIMI for STEMI, PURSUIT, SRI and EMMACE RS performed moderately well, with a c-statistics of 0.744, 0.775, 0.732 and 0.749, respectively. Of all the RS, three outperformed the other, achieving extremely good c-statstics, namely the ProACS, GRACE and ACTION Registry–GWTG RS. All of the RS predict short-term mortality. However, not all are equally efficient. The ProACS, GRACE and ACTION Registry–GWTG RS performed incredibly well when determining short-term mortality. A c-statistics of 0.908, 0.904 and 0.890 was calculated for each respective score. These results demonstrate a greater efficiency that that shown in previous studies. 3,6,12,18 The ProACS demonstrated impressive results. It was significantly better than all the other RS, apart from the ACTION Registry–GWTG and GRACE RS. The only setback was a HL-test value of under 0.05 in both the ProACS and ACTION Registry–GWTG, indicating model lack of fit. This resulted from the presence of NSTEMI patients in the study. All RS performed better at predicting in-hospital mortality in a STEMI setting. Again, the ProACS, ACTION Registry–GWTG and GRACE RS were the more accomplished RS, attaining c-statistics of 0.923, 0.911 and 0.899, respectively. Thesenumbersareespeciallyimpressivesincetheyoutperformed each of their derivation and validation cohorts. 3,12,18 ProACS demonstrated statistical superiority when compared to all others RS, apart from the ACTION Registry–GWTG and only marginal superiority when compared to the GRACE RS. In STEMI patients, these three RS revealed good fit. Once more, the TIMI for STEMI, PURSUIT, SRI and EMMACE RS had a satisfactory performance (c-statistics of 0.785, 0.809, 0.781 and 0.795, respectively). The CHA 2 DS 2 -VASc-HS and the C-ACS RS performed disappointingly, with c-statistics of 0.674 and 0.620, respectively. Concerning NSTEMI, the ProACS, GRACE and ACTION Registry–GWTG achieved a good predictive power, with c-statistics of 0.898, 0.878 and 0.895. In this particular population, both the ProACS and the ACTION Registry–GWTG showed lack of fit, thus interfering with the goodness of fit in the general population in these RS. The PURSUIT and EMMACE RS performed moderately good, with c-statistics of 0.742 and 0.702. It is impressive that the PURSUIT RS performed better at predicting a worse outcome in STEMI when compared to NSTEMI, since it is based upon NSTEMI patients. 4,5 The TIMI for STEMI and SRI predictably underperformed (c-statistics of 0.696 and 0.682), since both were developed for STEMI patients. 7 Again, the C-ACS revealed poor discriminatory accuracy (c-statistic 0.618) and the CHA 2 DS 2 -VASc-HS was unable to predict in-hospital mortality in NSTEMI patients (c-statistic of 0.534, p = 0.453). Risk scores and long-term prognosis The majority of the RS evaluated were developed solely for prediction of short-term prognosis. 3-13 In this population, all the RS underperformed when predicting all-cause mortality and non-fatal ACS at one-year follow-up (c-statistics < 0.7). Almost all the RS presented with a c-statistic ranging from 0.622 to 0.690, without a statistically significant difference when compared with the ProACS. Notably, the C-ACS was unable to predict the worst long-term prognosis (c-statistic 0.550, p = 0.057), even though it was validated for long-term prognosis prediction. 10 More studies are needed to develop RS with better discriminatory accuracy for predicting long-term prognosis in ACS patients. Limitations This is a single-centre retrospective, observational study of a small population. The analysis of the parameters was based on nonrandomized data. The population sample was relatively small and was composed by the sequential patients admitted in a single centralized hospital, thus it might represent a biased sample. Conclusions In this population, several RS showed good discriminatory accuracy at predicting short-term mortality. The ProACS, GRACE and ACTIONRegistry–GWTGRS performed incredibly, with c-statistics around 0.90. This revealed great predictive capability both in STEMI and NSTEMI patients. The TIMI for STEMI, PURSUIT, SRI and EMMACE RS performed moderately well. However, the CHA 2 DS 2 ‑VASc‑HS 20 and the C-ACS underperformed, perhaps due to differences between the cohort from which they were based on and the population sample of this study. In this real-world population, it is evident that RS developed from databases of large registries, such as the GRACE, ProACS and the ACTION Registry–GWTG, seem to fare better than those derived from clinical trials. RS developed from clinical trials tend to include skewed 28