Accurate risk stratification plays a very important role in the management of patients with acute and chronic coronary heart diseases (CHD). However, current prediction models that determine the potential adverse outcomes in patients with acute coronary syndromes do not take coronary artery lesions into account [
The study sample consisted of 423 Russian patients with ST-segment elevation myocardial infarction (STEMI) consecutively admitted to the Kemerovo Cardiological Centre in 2009. All the patients were the residents of Kemerovo city. In compliance with the recommendations of the European Society of Cardiology [
This study was approved by the local ethical committee, and all patients signed informed consent forms. Complaints, previous medical history, results of clinical examination, electrocardiogram data, levels of cardiospecific enzymes, systemic haemodynamic values, and echocardiogram data were registered. Colour duplex screening of the extracranial arteries (ECA) and lower extremity arteries (LEA) was performed on 5–7 days of hospitalization for all patients using the cardiovascular ultrasound system Vivid 7 Dimension (General Electric, USA) with a 5.7 MHz linear array transducer (for ECA), a 2.5–3 MHz curved array transducer, and a 5 MHz linear array transducer (for LEA). The extent of arterial stenosis was assessed in
Baseline characteristics.
ITT | |
---|---|
Mean age, mean years (95% CI) | 61.77 (60.68–62.87) |
Male, % | 68.08% |
Prior angina pectoris, % | 51.77% |
Prior myocardial infarction, % | 24.35% |
Prior stroke, % | 8.51% |
Prior diabetes mellitus, % | 18.20% |
Prior arterial hypertension, % | 88.65% |
Smoking status, % | 42.79% |
Killip classes II–IV at admission, % | 20.80% |
A statistical analysis was conducted using IBM SPSS Statistic 19.0.0 (IBM Company, USA). We calculated the percentage ratio, mean, and the 95% confidence interval for the mean. The analysis of differences between the independent groups was carried out using Pearson’s chi-square test. The Cox proportional hazards survival regression was applied to identify the independent predictors of the fatal outcomes. The value of the chi-square test and the area under the ROC-curve (AUC) were taken into consideration (C statistic). Missing data were not available during the procedure of multivariate analysis. Differences in the compared groups were considered to be statistically significant when the
The prevalence of PVD, as defined by the increased intima-media thickness (IMT) or by the various degrees of stenosis, was quite high (94.80%). In addition, 29.55% of the patients were characterised by stenosis with an occlusion of more than 50% of the vessel lumen, 17.73% of the patients were characterised by stenosis with an occlusion of 30%–50% of vessel lumen, and 44.52% of the patients were characterised by a stenosis with an occlusion of less than 30% of the vessel lumen or an increased IMT. Stratification of patients into groups revealed that the majority of patients (52.38%) had lesions in all 3 arterial territories (coronary arteries, ECA, and LEA), 46.37% of patients had CHD together with the lesions in the ECA, and only 1.25% of patients had manifestations of coronary artery atherosclerosis together with the lesions in the LEA.
Severe stenosis in the large arteries was more frequent among older patients and was associated with an increased incidence of angina pectoris, congestive heart failure, and prior myocardial infarction and stroke in the medical history. Acute heart failure (Killip II–IV), renal dysfunction, left ventricular systolic dysfunction, multivessel CHD, and rare cases of hyperchylomicronaemia were registered in enrolled patients with PVD (Table
Prevalence of risk factors among patients with STEMI according to the degree of stenosis in the noncoronary arteries (ECA or LEA).
Risk factors | Patient groups | ||||
---|---|---|---|---|---|
IMT < 1 mm | IMT ≥ 1 mm | Stenosis 30–50% | Stenosis over 50% | ||
Age > 60 years, % | 9.09 | 44.78 | 53.33 | 72.80 | |
Prior angina pectoris, % | 22.73 | 48.26 | 45.33 | 66.40 | |
Prior MI, % | 13.64 | 17.91 | 24.00 | 36.80 | |
Prior congestive HF, % | 4.55 | 3.48 | 9.333 | 14.40 | |
Prior stroke, % | 0 | 2.99 | 12.0 | 16.80 | |
Killip II–IV, % | 4.55 | 17.41 | 14.67 | 32.80 | |
Glomerular filtration rate (MDRD formula) <60 mL/min/1.73 m2, % | 3.4 | 42.5 | 24.8 | 29.3 | |
Concentration of triglycerides > 1.7 mmol/L | 73.68 | 54.04 | 45.16 | 35.35 | |
LV EF ≤ 40%, % | 9.09 | 12.44 | 18.67 | 25.60 | |
CA lesions > 2, % | 30.00 | 65.84 | 69.84 | 74.67 |
IMT: intima-media thickness; MI: myocardial infarction; HF: heart failure; LV EF: left ventricular ejection fraction; CA: coronary artery.
The GRACE score was calculated for all patients before discharge. On the basis of these scores, 167 subjects (39.48%) were included in a low risk group (score 27–99), 140 individuals (33.10%) were categorised in the average risk group (score 100–127), and 116 individuals (27.42%) were regarded as high risk group (score 128–263). The case fatality rates were 2.58%, 7.52%, and 22.94%, respectively, according to the distribution of GRACE score risk groups (
Stenosis of more than 30% of the ECA and LEA lumina was significantly associated with a high incidence of fatal outcomes within the one-year follow-up period (
The Kaplan-Meier curve, showing the 12-month survival depending on the severity of peripheral artery disease, is shown in Figure
The risk of fatal outcome after myocardial infarction during a year of followup based on the Kaplan-Meier curve, according to the severity of noncoronary atherosclerosis: 1—no lesions of peripheral arteries, 2—ECA and LEA stenosis with an occlusion of less than 30% of the vessel lumen, and 3—ECA or LEA stenosis with an occlusion of more than 30% of the vessel lumen.
We attempted to modify GRACE score model for the implementation of our results into the clinical practice. The Cox proportional hazards survival regression analysis with stepwise selection of independent risk factors for death was carried out for the achievement of this aim. The traditional risk factors (congestive heart failure, prior stroke, smoking status, and GRACE score) and the new risk factor, PVD with a varying degree of severity, were selected among various parameters (Table
Variables in the regression equation (KemScore model).
Risk factors | Wald | Exp( | ||
---|---|---|---|---|
GRACE score | 0.65 | 5.26 | 0.022 | 1.91 (1.13–3.35) |
Congestive heart failure ((1) no, (2) yes) | 1.02 | 5.24 | 0.022 | 2.83 (1.12–6.89) |
Prior stroke ((1) no, (2) yes) | 1.40 | 13.79 | <0.001 | 4.14 (1.88–8.52) |
Smoking ((1) no, (2) yes) | 0.85 | 4.68 | 0.031 | 2.26 (1.12–5.00) |
PVD ((1) no, (2) stenosis < 30%, and (3) stenosis ≥ 30%) | 1.30 | 17.28 | <0.001 | 3.73 (2.00–6.81) |
ROC curves of the GRACE score and KemScore.
The value of the AUC for the GRACE score model was 0.71 (95% CI = 0.63–0.79), whereas this value for the KemScore model was 0.83 (95% CI = 0.76–0.90). Thus, the addition of a new factor to the GRACE score model allows a more accurate risk stratification within one year after myocardial infarction. The previously described score system of risk factors was designed with the aim of convenient application in clinical practice (Table
Assessment of risk factors in cases with fatal outcomes within one year after myocardial infarction (KemScore model).
Risk factors | Point | |
---|---|---|
Risk of death after discharge | Low (27–99 scores) | 0 |
Average (100–127 scores) | 1 | |
High (128–263 scores) | 2 | |
Congestive heart failure | No | 0 |
Yes | 1 | |
Prior stroke | No | 0 |
Yes | 2 | |
Smoking | No | 0 |
Yes | 1 | |
Polyvascular diseases | No | 0 |
ECA and LEA stenosis with an occlusion of less than 30% of the vessel lumen | 2 | |
ECA and LEA stenosis with an occlusion of more than 30% of the vessel lumen | 3 |
The case fatality rate according to the total score number in the KemScore model.
Currently, there is no consensus on the incidence of multivessel atherosclerosis because of the different diagnostic approaches and study inclusion criteria. According to the literature, PVD incidence varies widely from 13.5% [
Undoubtedly, a case that presents with PVD determines the high risk status of a patient. However, it is impossible to determine the exact contribution of this particular condition to the risk stratification schemes at the present time, due to the different approaches in the diagnosis of peripheral artery lesions. A number of published studies also suggested that PVD patients constitute a high risk group. Ferreira-González et al. [
According to Spencer et al. [
The past literature has shown evidence to support the idea that the GRACE score is equally effective in assessing prognosis at 6 and 12 months after acute coronary syndrome [
Unfortunately, our study has several limitations. Firstly, the sample size was not large; secondly, we have not assessed the reclassification and other endpoints such as nonfatal myocardial infarction, stroke, and so forth.
Polyvascular diseases with even insignificant stenosis of the peripheral arteries not only determine the presence of multiple risk factors for cardiovascular diseases in patients with myocardial infarction but also appear to be an independent predictor of adverse (fatal) cardiovascular outcome. Therefore, this factor should be considered in the risk stratification.
The authors declare that they have no conflict of interests.