Predictive Value of CHA2DS2-VASC Score and Contrast Volume to Creatinine Clearance Ratio in Relation to Mehran Score for Contrast-Induced Nephropathy In ST- Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention

Myocardial infarction is a major cause of death and disability worldwide. Coronary reperfusion with primary percutaneous coronary intervention ( PPCI) or fibrinolytic therapy improves outcomes in patients with acute ST elevation myocardial infarction (STEMI).

PPCI can be defined as coronary angioplasty/stenting without prior administration of fibrinolytic agents or GPIIb/IIIa antagonists. These patients are usually treated with aspirin, a loading dose of clopidogrel together with heparin or bivalirudin, before the intervention.

If PPCI is performed promptly, the procedure is superior to fibrinolysis in restoring flow to the infarct-related artery in patients with STEMI.

Current guidelines for the treatment of STEMI recommend a door-to-balloon time of 90 minutes or less for patients undergoing PPCI. Door-to-balloon time has become a performance measure and is the focus of regional and national quality-improvement initiatives.

The contrast induced acute kidney injury has commonly been referred to as contrast induced nephropathy (CIN) defined as an increase in serum creatinine ≥25% or ≥0.5 mg/dl from baseline within 48-72 h after contrast exposure. (Weisbord, et al 2006.

CIN is the third most common cause of hospital-acquired acute kidney injury (AKI) due to impaired renal perfusion and use of nephrotoxic medications.

CIN accounts for 11-12% in all cases of in-hospital AKI, and is also associated with 6% of an overall in-hospital mortality rate.

Severe nephropathy after PCI (caused, at least in part, by radiographic contrast material) occurs in up to 2% of patients.

. It occurs most often among those with cardiogenic shock or underlying renal insufficiency and those of advanced age. . Anaphylactic reactions to radiographic contrast material are very rare. .

Age, left ventricular ejection fraction (LVEF) and estimated glomerular filtration rate (eGFR) are independent predictors of CIN development after PPCI for STEMI. .

CIN is strongly associated with late renal and cardiovascular adverse events. However, excluding peri-procedural hydration and the use of small amounts of low-osmolarity contrast media, few agents have proven to be effective for CIN. .

The identification of high-risk patients and preventive optimal hydration are key measures to reduce the incidence of CIN.

Several studies have assessed the role of contrast volume to creatinie clearance ratio (V/CrCl) as a reliable predictor of CIN with conflicting results and proposing different cut-off values. .

V/CrCl ≥ 6.15 was considered as the best discriminant value for the prediction of CIN, which occurred in 25.1% of patients with V/CrCl ≥ 6.15 versus 9.7% in patients with V/CrCl < 6.15. These results were also confirmed at multivariate analysis after correction for all baseline confounders.

The CHA2DS2-VASC score includes the following variables: congestive heart failure (CHF), hypertension, age ≥75 years, diabetes mellitus (DM), previous stroke, vascular disease, age 65 to 74 years, sex. The score is traditionally used for embolic risk stratification in atrial fibrillation (AF) patients.

The CHA2DS2-VASC score, used for embolic risk stratification in AF, has been reported recently to predict adverse clinical outcomes in patients with acute coronary syndrome (ACS), regardless of having AF.

Kurtul et al.(2016) investigated the correlation between the CHA2DS2-VASC score and CIN in ACS patients who underwent urgent PCI and concluded that CHA2DS2-VASC score can be used as a new, simple and reliable tool to predict CIN in patients with ACS who underwent urgent PCI.

Mehran score is a risk score for the prediction of CIN after PCI and it was reported by Mehran et al. In (2004).

The Mehran score has been the most widely used risk score for predicting the risk of CIN. In recent years, there was a proliferation of new scores and methods to predict CIN (Gao, et al.2014), however, their usefulness and extension to clinical practice is limited. The Mehran CIN score was designed in 2004 and based on its simplicity and because it allows early and correct identification of those individuals at high risk for CIN, it is currently the most widely used tool for predicting the risk of CIN.

That risk score includes 8 prognostic variables: hypotension, use of intra-aortic balloon pump, CHF, age, anaemia, DM, contrast media volume and eGFR.

The aim of the study:

1- To evaluate the role of the contrast volume to creatinine clearance ratio (V/CrCl) and the role of CHA2DS2-VASC score in the prediction of contrast-induced nephropathy after PPCI.

1. To compare the CHA2DS2-VASC score with Mehran risk score for predicting the risk of CIN after PPCI.
2. To detect the best cut-off point of CV/CrCl ratio in our population. Patients and methods

1-Study population: The study will include > 210 patients ( calculated sample size) who have STEMI and undergoing PPCI in Cath lab of Orman university Heart Hospital of Assiut University during the period between January 2018 and December 2018.

The sample size was calculated using Epi-info version 7. Based on previous studies, the incidence of CIN in patients undergoing PPCI for STEMI was 5.2% with a power of 80 and confidence level 95%, worst expected value 2.2%, the sample needed for the study was estimated to be about 210 patient [13].

3- Inclusion and Exclusion criteria

Inclusion criteria:

• All patients with STEMI who are eligible for primary PCI will be enrolled in the study.

Exclusion criteria:

1. If the coronary anatomy was not suitable for PCI.
2. If emergency bypass grafting was required.
3. Patients in chronic peritoneal or hemodialytic treatment. 4- Methods:

All patients will be subjected to:

1. Full history taking: including age, sex, history of DM, HTN, Smoking, dyslipidemia, history of cerebrovascular stroke, family history of renal troubles. Also to assess the onset of chest pain and time to reperfusion.
2. Thorough physical examination:

• General examination including intra-procedural blood pressure and heart rate assessment.
• Chest examination: to define Killip score.
• Cardiac examination to detect signs of heart failure. C. Twelve lead ECG: To diagnose STEMI and follow up. D. Collecting baseline venous blood samples for Random blood glucose, CBC, serum creatinin, GFR, electrolytes and lipogram before the procedure.

1. Coronary angiography and primary PCI will be done by an interventional cardiologist (member of PPCI team). After the procedure TIMI flow of the culprit vessel will be reported, as well as the volume of used contrast material and time of X-ray exposure.
2. Creatinine clearance will be calculated using Cockcroft-Gault formula and calculating CV/CrCl ratio.
3. Echocardiography : will be performed immediately after transfer of the patient to CCU to assess the ejection fraction of the heart ( on admission and before discharge).
4. Daily follow up of serum creatinine at 24, 48 hours. I. CHA2DS2-VASC score will be calculated for each patient. Based on the CHA2DS2-VASC score, patients are 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 or transient ischemic attack.
5. Mehran risk score will be calculated, that risk score includes 8 prognostic variables: hypotension (5 points, if systolic blood pressure <80 mmHg for at least 1 hour requiring inotropic support), use of intra-aortic balloon pump (5 points), CHF (5 points, if class III/IV by New York Heart Association Classification or history of pulmonary edema), age (4 points, if >75 years), anemia (3 points, if hematocrit <39% for men and <36 for women), diabetes mellitus (3 points ), contrast media volume (1 point per 100 ml), and estimated GFR 2 points, if GFR 60 to 40 ml/min per 1.73 m2; 4 points, if GFR 40 to 20; 6 points, if GFR <20).

Four categories of CIN risk of were established from the cut-off points and intervals defined by Mehran et al. 2010 as follow:

1. Low, <5 points.
2. Moderate, 6 to 10 points.
3. High, 11 to 15 points.
4. Very high, >15 points.
5. Statistical analysis:

Statistical analysis will be performed using the SPSS 20.0 statistical package. All enrolled patients will be divided into two groups according to CHA2DS2-VASC score. Clinical, laboratory, and procedural data will be compared with the use of Student t or Mann-Whitney U test for continuous variables (expressed as mean ± standard deviation for parametric variables, and median and interquartile ranges [25-75 percentile levels] for nonparametric variables) and chi-square test for categorical variables ( expressed as counts and percentages).

Receiver operating characteristic (ROC) curves will be used to identify the optimum cut-off values of V/CrCl ratio and CHA2DS2-VASC score and the number of CHA2DS2-VASC score to predict the development of CIN.

Multiple logistic regression analysis will be performed to evaluate the relationship between the Faculty of Medicine Institutional Review Board (IRB) Assiut Medical School Research Proposal Form 11 V/CrCl value or CHA2DS2-VASC score and the incidence of CIN, after correction for baseline confounding factors (clinical and demographic variables with a P-value<0.05), which will be entered in the model in block .