Research Article, Int J Cardiovasc Res Vol: 7 Issue: 3
Comparison between GRACE and TIMI Risk Scores in Predicting the Severity and Extent of Coronary Artery Disease in Patients with NSTEACS
*Corresponding Author : Mostafa A Elshahat
National Heart Institute, Cairo, Egypt
E-mail: [email protected]
Received: July 19, 2018 Accepted: July 25, 2018 Published: July 30, 2018
Citation: Bastawesy RB, Kabil HM, Ramzy AM, Ali MM, Elshahat MA (2018) Comparison between GRACE and TIMI Risk Scores in Predicting the Severity and Extent of Coronary Artery Disease in Patients with NSTE-ACS. Int J Cardiovasc Res 7:3. doi: 10.4172/2324-8602.1000352
Background: The prognostic value of the Global Registry of Acute Coronary Events (GRACE) risk score (GRS) and the thrombolysis in myocardial infarction (TIMI) risk index (TRI) has been reported in coronary artery disease (CAD) patients. We aimed to evaluate the relationship between the GRS, TRI, and severity of CAD evaluated by SYNTAX score (SS) in patients Non ST segment elvation acute coronary syndrome (NSTE-ACS).
Aim: The aim of this study is to compare the GRACE risk score and the TIMI risk index in predicting the extent and severity of coronary artery disease in patients with (NSTE-ACS) using Syntax score
Methods: A total number of 100 patients were admitted to National Heart Institute CCU with NSTE-ACS undergoing coronary angiography. Patients with a history of coronary artery bypass surgery, those who had missing data for calculating the GRS and TRI, and those whose systolic blood pressure (SBP) was more than 180 mm Hg or whose diastolic blood pressure (DBP) was more than 110 mm Hg were excluded from the study The GRS and TRI were calculated on admission using specified variables. The severity of CAD was evaluated using the SS. The patients were divided into low (GRS<109), intermediate (GRS 109-140), and high (GRS>140) risk groups according to GRS score and into group 1 (TRI 0-2), group 2 (TRI 3-4), and group 3 (TRI 5-7) according to TRI score. A Pearson correlation analysis was used for the relation between GRS, TRI, and SS.
Results: There were significant correlation between both GRACE and TRI score and SS (r=0.551, p<0.001) (r=0.309, p=0.046) respectively, there were no significant difference between area under the curve in predicting extent of CAD p= 0.185 although GRACE score showed higher significance in correlation with SS
Conclusion: The GRS is more associated with SS than TRI in predicting the severity of CAD in patients with ACS
Keywords: Acute coronary syndrome; GRACE risk score; SYNTAX score; TIMI risk index
GRS: Grace Risk Score; SS: Syntax Score; TRI: Timi Risk Index; NSTE-ACS: Non ST Segment Elevation-Acute Coronary Syndrome; CAD: Coronary Artery Disease.
Coronary artery disease (CAD) is one of the main causes of death and disability in the world. According to the American Heart Association, CAD was responsible for approximately 445,687 deaths in the United States in 2005, representing 20% of all deaths that year .
Patients with acute coronary syndromes are a heterogeneous group of population with varying degree of risks of death and recurrent cardiac events, in short and long-term outcome . Therefore, algorithms that aid clinicians in predicting outcomes may be helpful in directing management and in supplying valuable information for the patients and their families. Clinically wise risk stratification tool should be simple and applicable at the bedside and should make use of the clinical data that are routinely available at hospital presentation .
In these groups, early risk stratification plays a central role, as the benefit of recent and more invasive and costly treatment strategies seems to be appropriate to the risk of adverse clinical events (cost-effectiveness). Different scores (clinical and angiographic) are now readily available based on initial clinical history, ECG, echocardiography, laboratory tests and coronary angiography that enable early risk stratification on admission. Clinical scores: The thrombolysis In Myocardial Infarction (TIMI) score was developed with the databases from large clinical trials of non ST-segment elevation acute coronary syndrome (NSTE-ACS) , and in patients with unstable angina/non ST-segment elevation myocardial infarction (UA/NSTEMI) .
The Global Registry of Acute Coronary Events (GRACE) score was developed from the registry with a population of patients across the entire spectrum of ACS. It is accurate for determining both inhospital and long-term mortality in patients with ACS in the era of high-sensitivity cardiac troponin (hs-cTn) .
The SYNTAX (Synergy between PCI with TAXUS and Cardiac Surgery) model is one of the scoring systems for determining the extent and severity of CAD. Although these scoring systems have many advantages, they require an invasive method, such as coronary angiography, to perform the scoring. Therefore, we still need an easily accessible, cost-effective, and noninvasive method to carry out risk stratification by determining the extent and severity of CAD in ACS patients .
Study design and population
100 Patients with NSTE-ACS who were admitted to the coronary care unit of National Heart Institute between February 2016 and February 2017 were retrospectively evaluated .
NSTE-ACS Patients with a history of coronary artery bypass surgery, those who had missing data for calculating the GRS and TRI, and those whose systolic blood pressure (SBP) was more than 180 mmHg or whose diastolic blood pressure (DBP) was more than 110 mmHg were excluded from the study
The patients were divided into low (GRS<109, n=48), intermediate (GRS 109-140, n=32), and high (GRS>140, n=20) risk groups according to GRS score and into low group 1 (TRI 0-2, n=28), moderate group 2 (TRI 3-4 n=50), and high group 3 (TRI 5-7 n=22) according to TRI score. The GRS and TRI were calculated on admission using specified variables. The severity of CAD was estimated by coronary angiography using syntax score (Version 2.11 of the SYNTAX score calculator was used), Patients were divided into low [Group 1 (SS 0-22), n=56)], intermediate [Group 2 (SS 23-32), n=30)], and high SYNTAX score [Group 3 (SS ≥ 33), n=14)].
A total of 100 patients were enrolled in this study. Table 1 shows the characteristics of all patients. There were significant differences regarding mean age (p<0.001), heart rate (p<0.001), SS (p<0.001), TRI (p<0.001), systolic blood pressure (p<0.001), cardiac arrest (p<0.001) ,Troponin (p<0.001), creatinine (p<0.001) and signs of heart failure in all patients between the low-, intermediate-, and high-risk groups (Table 2).
|Age (years) Range (Mean ± SD)||27-81 (57.62 ± 12.27)|
|Risk factors||Number (%)|
Table 1: characteristics of the patients.
|All Parameters||GRACE Score||F/x2*||p-value|
|Female||20 (41.7%)||4 (12.5%)||8 (40.0%)||8.241*||0.016|
|Male||28 (58.3%)||28 (87.5%)||12 (60.0%)|
|Age (years)||51.75 ± 12.89||60.19 ± 7.43||67.60 ± 8.98||16.927||<0.001|
|DM||22 (45.8%)||12 (37.5%)||14 (70.0%)||5.382*||0.068|
|HTN||26 (54.2%)||26 (81.3%)||18 (90.0%)||11.468*||0.003|
|Smoking||30 (62.5%)||16 (50.0%)||12 (60.0%)||1.273*||0.529|
|Disp.||18 (37.5%)||10 (31.3%)||16 (80.0%)||13.454*||0.002|
|AF||6 (12.5%)||0 (0.0%)||2 (10.0%)||4.212*||0.122|
|V.T.||0 (0.0%)||0 (0.0%)||10 (50.0%)||44.444*||<0.001|
|Echo EF %|
|<40||4 (8.3%)||8 (25.0%)||10 (50.0%)||14.53*||0.002|
|>40||44 (91.7%)||24 (75.0%)||10 (50.0%)|
|HR||97.92 ± 17.98||105.94 ± 20.10||107.00 ± 21.05||2.399||0.096|
|SBP||137.08 ± 17.62||132.50 ± 20.16||105.00 ± 22.59||19.778||<0.001|
|Creat||1.05 ± 0.24||1.33 ± 0.36||1.37 ± 0.25||13.868||<0.001|
|Arrest||0 (0.0%)||0 (0.0%)||8 (40.0%)||34.783*||<0.001|
|ST Changes||28 (58.3%)||24 (75.0%)||16 (80.0%)||4.105*||0.128|
|Trop||26 (54.2%)||28 (87.5%)||20 (100.0%)||19.872*||<0.001|
|Sign HF||4 (8.3%)||12 (37.5%)||10 (50.0%)||15.974*||<0.001|
Table 2: Baseline clinical, laboratory, ECG and echocardiographic characteristics of patient groups according to GRACE Risk Score.
There were significant differences regarding history of CAD (p<0.001), ST segment changes (p<0.001), presence of more than 3 CAD risk factors in all patients between groups according to TRI (Table 3).
|All Parameters||TIMI Risk Index Score Class||F/x2*||p-value|
|Female||6 (21.4%)||18 (36.0%)||8 (36.4%)||1.998*||0.368|
|Male||22 (78.6%)||32 (64.0%)||14 (63.6%)|
|Age (years)||53.93 ± 12.23||56.56 ± 12.63||64.73 ± 8.43||5.624||0.005|
|DM||8 (28.6%)||24 (48.0%)||16 (72.7%)||9.624*||0.008|
|HTN||20 (71.4%)||32 (64.0%)||18 (81.8%)||2.348*||0.309|
|Smoking||18 (64.3%)||28 (56.0%)||12 (54.5%)||0.644*||0.725|
|Disp.||8 (28.6%)||20 (40.0%)||16 (72.7%)||10.398*||0.006|
|AF||2 (7.1%)||6 (12.0%)||0 (0.0%)||3.028*||0.220|
|V.T.||0 (0.0%)||0 (0.0%)||10 (45.5%)||39.394*||<0.001|
|<40||4 (14.3%)||10 (20.0%)||8 (36.4%)||3.733*||0.155|
|>40||24 (85.7%)||40 (80.0%)||14 (63.6%)|
|Age >65||6 (21.4%)||14 (28.0%)||12 (54.5%)||6.945*||0.031|
|>3 CAD Risk factors||8 (28.6%)||24 (48.0%)||22 (100.0%)||26.754*||<0.001|
|Known CAD||0 (0.0%)||18 (36.0%)||18 (81.8%)||35.795*||<0.001|
|ASA Use in Past 7 days||6 (21.4%)||12 (24.0%)||14 (63.6%)||13.028*||0.002|
|Severe Angina episodes in 24 h||14 (50.0%)||26 (52.0%)||12 (54.5%)||0.102*||0.950|
|ST changes >0.5 mm||8 (28.6%)||38 (76.0%)||20 (90.9%)||25.791*||<0.001|
|Ve Trop.||12 (42.9%)||38 (76.0%)||22 (100.0%)||20.748*||0.002|
Table 3: Baseline clinical, laboratory, ECG and echocardiographic characteristics of patient groups according to TIMI Risk Index.
In the correlation analysis, there were highly significant positive correlations between GRS and SS (r=0551, p<0.001) (Figure 1) and between GRS and TRI (p<0.001), and there were significant correlations between TRI and SS (r=0.309, p=0.046) The relationship between GRS and SS in patients with ACS is shown in Figure 1. The area under the ROC curves for GRS was 0.75 (95% CI: 0.66-0.83, p<0.001) in the prediction of the severity of CAD (SS >22) in patients with ACS (Figure 2). While area under the ROC curves for TRI was 0.67 (95% CI: 0.57-0.76, p=0.04) in the prediction of the severity of CAD (SS >22).
The TIMI and the GRACE risk scores are the two most commonly used scores to risk-stratify NSTE-ACS patients at presentation. The risk stratification is important as it has been consistently proved that early coronary intervention in high-risk patients improves clinical outcomes.
In our study we evaluated the correlation between TIMI and GRACE risk scores with the complexity of coronary artery disease using SYNTAX score in 100 patients admitted to National Heart Institute CCU with non-ST elevation ACS undergoing coronary angiography. We excluded patients with blood pressure more than 180/110 and patients who had previous PCI or CABG.
Our patients were classified into TIMI and GRACE risk scores of low, intermediate and high risk and compared with the angiographic SYNTAX score among the three groups .The study concluded that for every increase in the risk category in both TIMI and GRACE risk scores there is an increase in the likelihood that patients will have high SYNTAX score.
It was observed that there was a significant correlation between both TRI and SYNTAX scores (r=0.309, p=0.046). While GRACE score showed more significance than TRI (r=0551, p<0.001) in predicting extent and severity of CAD assessed by SYNTAX score.
Also we concluded presence of significant correlation between TIMI risk score and GRACE score of 6 months mortality with. P value <0.001 (r =0.515). we found highly significant difference (p<0.001), regarding age heart rate, systolic blood pressure and positive troponin in patients with low intermediate and high grace score ,while we found significant differences (p<0.001), regarding history of CAD, presence of more than 3 CAD risk factors and ST segment in patients with low intermediate and high TRI.
Receiver operating characteristics (ROC) curve was used to define the best cut off value of Grace score which was >117, with sensitivity of 81.8% specificity of 71% positive predictive value of 69%, negative predictive value of 83% with diagnostic accuracy of 75.6%. while cut off value of TIMI Risk Index which was >3, with sensitivity of 50% specificity of 75% positive predictive value of 82%, negative predictive value of 66% with diagnostic accuracy of 67.3%.
Our study showed that normal coronary arteries and noncritical CAD were more often found in patients in the low-risk group by TIMI and GRACE score, and three-vessel or left-main lesions of coronary artery were more often found in patients in the high-risk group by TIMI GRACE score. Specifically, low-risk patients are more likely to have nor-mal coronary arteries or non-significant CAD, whereas intermediate and high-risk patients are more likely to have significant CAD (>2 vessels, or left main CAD). In other words, the GRACE score is also important for determining the severity of the CAD beside predicting death within 6 months of hospital discharge.
This was concordant with Garcia et al.  who compared TIMI score was with the results of coronary angiography in 688 patients with NSTEACS. They excluded patients who had previous myocardial revascularization surgery or recent PCI. The authors concluded that for every increase in the risk category, there is an increase not only in the percentage of adverse events, but also in the likelihood that patients will have disease involving three vessels or injury to the left main coronary artery. In each increased risk category, 3-vessel disease or left main coronary disease was shown to be more frequent
In another study, the PRISM-PLUS study, in 1491 patients with ACS, Mega et al.  showed that there were more severe coronary lesions and left main coronary lesions in patients with high TIMI (5- 7) risk scores compared to those with low TIMI (0-2) risk scores .
These results were confirmed in the retrospective study of Salem et al.  which evaluated the extent and severity of coronary artery lesions in a retrospective analysis of 239 patients with non-ST elevation ACS. The authors classified patients into TIMI risk of low, intermediate and high risk and compared the angiographic findings among the three groups.
And found that patients with risk scores of 0-2 had significantly normal angiography or non-significant coronary artery disease, compared with a score of 3-4 (36.3% versus 13%, p>0.001) and with a score of 5-7 (36.3% vs. 0%, P=0.002). On the other hand, disease involving three vessels or lesions of the left main coronary artery were found more frequently among the high risk patients compared with intermediate (66.7% vs. 26%; P=0.01) and low risk (66.7% vs. 13.2%; P<0.001). The authors concluded that higher TIMI risk scores correlated with more serve coronary artery disease and concordant with Cakar et al.  included 245 patients with NST ACS .Based on the GRACE risk score classification system, the patients were divided as low (n=97, 39.6%), intermediate (n=84, 34.3%), and high (n=64, 26.1%) risk groups. Patients with high GRACE score have more severe CAD, therefore GRACE score showed significant correlation with respective angiographic Gensini scores by Pearson’s correlation (r=0.189, p=0.03).
E.Öner et al.  also stated that after assessment of 145 patients with non-ST elevation ACS and undergoing coronary angiography. TIMI and GRACE risk scores were calculated and coronary artery disease severity and were assessed by using the SYNTAX score algorithm. The TIMI score is of no use in predicting serve extended CAD, whereas the relationship between the GRACE and SYNTAX scores may have some clinical implications.
Accordingly the TIMI risk score, with its weak association to the SYNTAX score, does not appear to be a good candidate in predicting the extension and severity of CAD. These contradictory results can be explained as; although a statistically signification association was observed, the TIMI score was not able to differentiate between SYNTAX score risk tertiles (ANOVA, p=0.091). The area under curve of the TIMI score was not statistically significant either. The GRACE score has shown a greater prognostic value as compared with that of the TIMI score .
This greater prognostic value was translated into a better discriminatory capacity in our study. The area under the curve of the GRACE score in this study population showed good discriminatory capacity between the patients with and without a high risk (>33) SYNTAX score.
Increased both TIMI and GRACE scores not only associated with the presence of coronary artery disease but also with lesions complexity, severity and extent.
GRACE score is more predictive for lesions complexity than TIMI risk Index when calculated by SYNTAX score.
Conflict of Interest
The authors declare that they have no conflict of interest.
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