Myocardial contrast echocardiography assessment of mouse myocardial infarction: comparison of kinetic parameters with conventional methods

This study explores the use of a minimally invasive assessment of myocardial infarction (MI) in mice using myocardial contrast echocardiography (MCE). The technique uses existing equipment and software readily available to the average researcher. C57/BL6 mice were randomized to either MI or sham surgery and evaluated using MCE at 1- or 2-weeks post-surgery. Size-isolated microbubbles were injected via retro-orbital catheter where their non-linear characteristics were utilized to produce the two-dimensional parameters of Wash-in-Rate and the Peak Enhancement, indicative of relative myocardial perfusion and blood volume, respectively. Three-dimensional cardiac reconstructions allowed the calculation of the Percent Agent, interpreted as the vascularity of the entire myocardium. These MCE parameters were compared to conventional assessments including M-Mode, strain analysis, and 2,3,5-Triphenyltetrazolium chloride (TTC) staining. Except for the Wash-in-Rate 2-week cohort, all MCE parameters were able to differentiate sham-operated versus MI animals and correlated with TTC staining (P < 0.05). MCE parameters were also able to identify MI group animals which failed to develop infarctions as determined by TTC staining. This study provides basic validation of these MCE parameters to detect MI in mice complementary to conventional methods while providing additional hemodynamic information in vivo.

Assessment of no-reflow phenomenon by myocardial contrast echocardiography in patients with acute myocardial infarction with ST-segment elevation

Funding Acknowledgements Type of funding sources: None. Background The noninvasive assessment of myocardial perfusion by echo contrast agents in patients with acute myocardial infarction with ST-segment elevation (STEMI) after successful revascularization is becoming a relevant clinical reality. Perfusion imaging techniques with myocardial contrast echocardiography (MCE) remains the least studied and most promising ultrasound technology for the diagnosis of no-reflow phenomenon. Purpose To study the echocardiographic and angiographic characteristics of the no-reflow phenomenon detected by MCE in patients with STEMI. Methods The study included 43 patients aged from 40 to 82 years in acute stage of myocardial infarction. Patients were divided into two groups: 32 patients characterized by sufficient myocardial reperfusion after revascularization according to MCE results and 11 patients were with the impaired perfusion. Results The patients with impaired perfusion demonstrated a greater size of the left ventricular (LV) asynergy (40.1 ± 2.2% vs 27.4 ± 8.5%, p &lt; 0.001). LV dilatation (LV end-systolic volume 67.3 ± 20.3 ml vs 51.8 ± 17.2 ml, p = 0.015), impaired LV ejection fraction (39.5 ± 3.4% vs 47.2 ± 4.9%, p &lt; 0.001), and significant mitral regurgitation (45.5% vs 3.1%, p = 0.011) with a decrease in DP/DT (979.9 ± 363.4 mmHg/s vs 1565.7 ± 502.8 mmHg/s, p &lt; 0.001) was more often detected in this group. In more than a quarter of these patients, coronary angiography showed no perfusion disorders after revascularization. In the group with impaired perfusion by MCE, the single-vascular lesions (46.9% vs 9.1%, p = 0.033), the lesions of the anterior interventricular artery (90.9% vs 40.6%, p = 0.004), and acute occlusion (100% vs 68.8%, p = 0.043) were more often determined. Conclusion According to the results of MCE, the echo signs of LV dysfunction were more pronounced after successful revascularization in patients with STEMI and myocardial perfusion disorders. The SYNTAX score was twice higher in these patients compared to the patients with recovered perfusion. In addition, no-reflow phenomenon by MCE was observed in the most patients with anterior interventricular artery lesion.

Prognostic value of resting myocardial contrast echocardiography: a meta-analysis

Background: Resting myocardial perfusion (MP) and wall motion (WM) imaging during real-time myocardial contrast echocardiography (MCE) improves the detection of coronary artery disease (CAD). However, its prognostic role in different clinical settings (emergency department and outpatient setting) remains unclear. Methods: A systematic search in PubMed and Embase databases, and the Cochrane library, was conducted to evaluate the role of resting MP and WM in predicting major adverse cardiac events (MACE), including death, nonfatal myocardial infarction (NFMI) and urgent revascularization in patients presenting to either outpatient clinics or emergency departments with suspected symptomatic CAD. Summary receiver operating characteristic (SROC) curves, sensitivity and specificity plots were applied to assess diagnostic performance using RevMan 5.3. Results: Seven studies met criteria, including 3668 patients (six with follow up ranging from 2 days to 2.6 years). The Relative Risk (RR) for predicting MACE in patients with both abnormal resting MP and WM was 6.1 (95% CI, 5.1–7.2) and 14.3 (95% CI, 10.3–19.8) for death/NFMI, when compared to normal resting MP and WM patients. Having both abnormal resting MP and WM was also more predictive of MACE (RR, 1.7; 95% CI 1.5–1.9) and death/NFMI (RR, 2.2; 95% CI, 1.8–2.7) when compared to abnormal WM with normal resting MP. Conclusion: In this meta-analysis of both ED and outpatient clinic presentations for suspected CAD, having both a resting regional MP and WM abnormality identifies the highest risk patient for adverse events.