Abstract
Background
Following an acute coronary syndrome, ischemic myocardial dysfunction has several degrees of severity and different outcomes from a total or partial recovery to an irreversible injury.
In this study led in non-ST elevation myocardial infarction (NSTEMI) patients without otherwise previous non-ischemic cardiomyopathy (NICM), we investigated the correlation between 2D global longitudinal strain (GLS) and angiographic prognostic factors.
The ability of territorial longitudinal strain (TLS), defined as the sum of segmental strain in a coronary territory,to identify culprit artery occlusion was also assessed.
Methods
82 consecutive NSTEMI patients were prospectively screened for inclusion; 70 of them without NICM were enrolled. Severe coronary artery disease (CAD) was defined as three-vessel disease or a left main disease. Group 1 and 2 were defined by the presence or not of severe CAD. Statics ‘analyses was performed with IBM SPSS Statistics (version 22).
Results
mean age of patients was 60, 2 ±10 years. 37 patients had diabetes mellitus (53%), 31 had hypertension (44%), 21 had dyslipidemia (30%) and 5 had renal insufficiency (7%). Severe CAD was present in 24 patients (34%).
The first ultrasound exam showed that mean EF was 49 ± 11, mean WMSI was 1.43 ± 0.4 and mean GLS was -14.9 ± 4.
GLS was higher in group 1 (-12.82 ± 0.95 vs -16.04 ± 0.42; p < 0.001); LVEF and WMSI in group 1 and 2 were (43.3 ± 13.5% Vs 52.7 ± 7.9%; p < 0.001) and (1.64 ± 0.1 Vs 1.32 ± 0.04; p < 0.001) respectively. Correlations were found between LVEF and GLS (p = 0.004), and between WMSI and GLS (p = 0.002) . TLS was able to discriminate between coronary stenosis of LAD, LCX or RCA and to predict the occlusion of the culprit vessel: 7 patients had acute coronary occlusion (10%). TLS was -7.4 ± 5.1 in patients with coronary occlusion and -14.1 ± 6 in the absence of coronary occlusion (p < 0.001). A cut off of -9.5 was able to detect this occlusion with a specificity of 82% and a sensitivity of 85%.
The second ultrasound exam, performed after a median of 10 ± 3.1 months, showed a statistically significant improvement of EF (53 ± 10, p =0.02), WMSI (1.35 ± 0.39, p= 0.01) as well as GLS (-17.1 ± 4.2, p =0.004).
Patients who received only medical treatment (n = 11) had the lowest variation of EF (47% to 48 %; p = 0.7), WMSI (1.62 to 1.59; p = 0.69) and GLS (14.2 to 15.2; p = 0.2) with no statistical correlation between the two exams. While patients who had PCI or bypass revascularization, had the best outcome with improvement of EF (49% to 53%; p = 0.002), WMSI (1.4 to 1.32;p = 0.01) and GLS (15 to 17.4;p = 0.004).
Conclusion
GLS is a strong diagnostic and prognostic ultra sound parameter for NSTEMI patients correlated to CAD severity. Strain is a reliable parameter during follow up.TLS can be used to localize the culprit coronary artery and especially to predict its occlusion during the acute phase of NSTEMI which can lead to a different therapeutic strategy.
Right Ventricle Involvement in Patients with Acute ST Elevation Myocardial Infarction: Is Echocardiography Good Enough in Diagnosing It?
