Role of left atrial reservoir in the prediction of increased left ventricular filling pressures in patients with ST-segment elevation myocardial infarction

Background. Non-invasive assessment of the hemodynamic status can be useful in acutely decompensated patients for optimizing medical management. In this respect, several echocardiographic parameters have been proposed to estimate left ventricular (LV) filling pressures; however, this matter is still debated. Purpose. We aimed to investigate, in patients with ST-segment elevation myocardial infarction (STEMI), the relations between the echocardiographic (TTE) parameters currently employed for assessing LV filling pressures and the serum levels of brain natriuretic peptide (BNP). Methods. Thirty consecutive patients (age: 61.9±10.2; 25 males) with STEMI underwent serum BNP dosage and, at the same time, TTE with the calculation of the following parameters: mitral E/A and E deceleration time [DTE], E/flow propagation velocity (E/Vp), E/e’ averaged from septal and lateral annulus, the ratio between isovolumic relaxation time and the difference between the time from QRS to E-wave and e’ wave onset (IVRT/TE-e’) and the ratio between venous pulmonary systolic and diastolic velocities (S/D). In addition, specke-tracking analysis (Esaote, MyLabDesk) was performed to obtain global longitudinal strain (GLS), systolic and early-diastolic longitudinal strain rate (SRs’ and SRe’; E/SRe’ was also calculated), LV apical early-diastolic untwisting rate (Apical Rot-rate), left atrial (LA) reservoir and LA stiffness (E/e’ / LA reservoir). We subdivided the population in two groups according to the value of BNP: Group A (BNP =100 pg/ml) and Group B ( BNP<100 pg/ml). Patients with: LV ejection fraction (LVEF) < 40 %, more than mild valvular heart disease and atrial fibrillation were excluded. Results. There was a higher prevalence of inferior than anterior STEMI (17 vs 13, p = 0.046). After comparing A and B groups, we found that almost all parameters were comparable between groups (E/A: 1.0±0.3 vs 0.8±0.1 p 0.34; DTE: 202±35 vs 192±31, p 0.48; E/Vp: 1.8±0.6 vs 1.5±0.2 p 0.37; E/e’: 8.8±2.1 vs 8.1±2.1 p 0.39; IVRT/TE-e’: 5.2±5.7 vs 5.4±3.1 p 0.95; S/D: 1.2±0.3 vs 1.4±0.1 p 0.22; GLS: -15.9±3.4 vs -16.4±3.6 p 0.68; SRs’: -1.0±0.2 vs -0.9±0.1 p 0.63; SRe’: 0.92±0.31 vs 0.93±0.26 p 0.94; E/SRe’: 0.86±0.3 vs 0.98±0.5 p 0.43; Apical Rot-rate: -41.7±20.7 vs -44.1±15.3 p 0.77) with the only exception of LVEF (47.3±4.8 vs 53±2.5, p 0.001), LA reservoir (35.1±8.3 vs 52.6±8.1, p <0.001) and LA stiffness (0.29±0.1 vs 0.18±0.1, p 0.018). BNP was 232.7±142.7 and 72.4±26.8 in A and B (p 0.001); troponin I was comparable between A and B (49.1±35.9 vs 32.8±29.2 p 0.18). On univariate analysis, only LVEF and LA reservoir were predictors of elevated BNP levels (OR 0.77 [0.65-0.92] p 0.005 and 0.83 [0.74-0.93] p 0.002); on multivariate analysis, LA reservoir was the only independent predictor of higher BNP levels (OR 0.84 [0.73-0.96] p 0.013). Conclusions. LA reservoir, better than other echocardiographic parameters, reflects higher LV filling pressures in patients with STEMI.