Effect of elective percutaneous coronary intervention of left anterior descending coronary artery on regional myocardial function using strain imaging

Subclinical dysfunction of remote myocardium is related to high NT-proBNP and affects global contractility at follow-up, independently of infarct area

Background

In ST-segment elevation myocardial infarction (STEMI), predictors of subclinical dysfunction of remote myocardium are unknown. We prospectively aimed at identifying clinical and biochemical correlates of remote subclinical dysfunction and its impact on left ventricular ejection fraction (LVEF).

Methods

One-hundred thirty-three patients (63.9 ± 12.1 years, 68% male) with first successfully treated (54% anterior, 46% non-anterior, p = 0.19) STEMI underwent echocardiography at 5 ± 2 days after onset and at 8 ± 2-month follow-up, and were compared to 13 age and sex-matched (63.3 ± 11.4) healthy controls. All 16 left ventricular (LV) segments were grouped into ischemic, border, and remote myocardium: mean value of longitudinal strain (LS) within grouped segments were expressed as iLS, bLS, rLS, respectively. LV end-diastolic (EDV), end-systolic (ESV) volumes indexed for body surface area (EDVi, ESVi, respectively), LVEF and global LS (GLS) were determined. Creatinine, glomerular filtration rate, admission level of NT-pro-brain-natriuretic peptide (NT-proBNP) and troponin peaks were considered for the analysis.

Results

At baseline, rLS (15.5 ± 4.4) was better than iLS (12.9 ± 4.8, p < 0.001), but lower than that in controls (19.1 ± 2.7, p < 0.001) and similar to bLS (15 ± 5.4, p = ns), and did not differ between patients with single or multivessel coronary artery disease (CAD). At multivariate regression analysis, only admission NT-proBNP levels but not peak Tn levels independently predicted rLS (β = -0.58, p = 0.001), as well as iLS (β = -0.52, p = 0.001). Both at baseline and at follow-up, rLS correlated to LVEF similarly to iLS and bLS (p < 0.001 for all). Median value of rLS at baseline was 15%: compared to patients with rLS ≥ 15% at baseline, patients with rLS < 15% showed lower LVEF (52.3 ± 9.4 vs. 58.6 ± 7.6, p < 0.001) and GLS (16.3 ± 3.9 vs. 19.9 ± 3.2), and higher EDVi (62.3 ± 19.9 vs. 54 ± 12, p = 0.009) and ESVi (30.6 ± 15.5 vs. 22.3 ± 7.6, p < 0.001) at follow-up.

Conclusion

In optimally treated STEMI, dysfunction of remote myocardium assessed by LS: (1) is predicted by elevated NT-proBNP; (2) could be independent of CAD extent and infarct size; (3) is associated to worse LV morphological and functional indexes at follow-up.

Early prediction of ventricular functional recovery after myocardial infarction by longitudinal strain study

BACKGROUND

There are some suggestions that global myocardial strain (GLS) early after ST-elevation myocardial infarction (STEMI) is a predictor of improvement in left ventricular ejection fraction (LVEF). The goal of this study was to evaluate LV recovery after STEMI intervention based on GLS values.

METHODS

The study population consists of 43 patients with acute STEMI and no history of prior coronary intervention treated with primary percutaneous coronary intervention. LVEF and myocardial strain indices were measured 48 hours and two months after STEMI by transthoracic echocardiography and speckle tracking method. More than 5% improvement in LVEF was considered significant.

RESULTS

GLS values were significantly higher in patients with >5% improvement in LVEF 2 months after the STEMI (GLS=15.76% in patients with >5% improvement vs. 11.54% in the other group, P<0.05). ROC analysis suggested GLS values more than 13.5 to be a predictor of significant LVEF improvement 2 months after STEMI. Higher GLS was observed in patients with inferior, posterior and inferoseptal STEMI versus anterior, extensive or anteroseptal STEMI and in patients with right coronary occlusion versus occlusion of the left anterior descending or circumflex arteries.

CONCLUSION

We have observed that early longitudinal LV strain after STEMI is a predictor of recovery after STEMI. This is a useful method to predict early LV recovery after STEMI. GLS values of more than 13.5% are a significant predictor of significant LVEF improvement.