Study of Global Longitudinal Strain and N Terminal Pro BNP as Predictors of Outcome in Acute ST-Segment Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Interventions

Risk stratification of patients presenting with Acute ST-segment elevation myocardial infarction (STEMI) is of greatest importance as it may help to start early therapeutic procedures that could improve the outcome. Our study is designed to assess the prognostic value of N-terminal pro brain natriuretic peptide (NT-proBNP) and global longitudinal strain (GLS) of the left ventricle measured by 2 dimensional speckle tracking echocardiography (STE) in patients presenting with acute STEMI and treated by primary percutaneous coronary interventions (PPCI).

the study prospectively included 100 patients(their age 55.69 ±8.70 years, and 75% were males)presented to our institute (from march 2019 to December 2019) by acute STEMI and treated by PPCI within 12 hour of the onset of chest pain, excluding those with left ventricular ejection fraction ≤40%, left bundle branch block, atrial fibrillation, significant valvular disease, patients with non cardiac causes that interfere with NT-Pro BNP level eg.(renal failure, chronic obstructive pulmonary disease, acute respiratory distress syndrome, pneumonia, liver cirrhosis, hyperthyroidism, and on those on chemotherapy). All patients were subjected to peripheral samples of plasma for analysis of NT- proBNP and 2dimentional STE for calculation of the GLS, both were done within 24 hours of admission, and follow up of all patients were done for 6 months to assess outcome.

The mean GLS for all patients was -10.41 ± 3.59%, and the mean NT- proBNP (2090.1 ± 1375.8) pg/ml. 20 patients (20%) had adverse events during the 6 month follow up including (1(1%) had all cause mortality, 2(2%) had cardiovascular mortality, 6(6%) had reinfarction, 11(11%) had heart failure hospitalization, and according to ROC curve analysis the GLS cut off value of (≤- 8) was able to discriminate patients with adverse outcome (AUC=0.971, p value<0.001,CI=“0.940-1.001”,sensitivity=90%, specificity=91.67%, PPV=78.3%, NPV=96.5%) (figure 1, 2), also according to ROC curve analysis NT-pro BNP cut off value of (>2318pg/ml) was able to discriminate patients with adverse outcome (AUC=0.802,p value<0.001, CI=“0.685-0.920”, sensitivity=89%, specificity=75%, PPV=51.6%, NPV=91.8%) (Figure 3, 4).

There was a statistically significant inverse correlation between GLS and NT- ProBNP (r=-0.492*, p value<0.001). In multivariate COX regression analysis for the parameters affecting the outcome, GLS was shown to be the most significant parameter in the prediction of reaching adverse outcome in STEMI patients (p value=0.003, OR “95%C.I”= 0.721 (0.580–0.896).

our study concluded that both GLS and NT-proBNP are significantly related to adverse outcome with more superiority of the GLS to NT- pro BNP in adverse outcome prediction in patients acute STEMI treated by PPCI.