Region of Interest Tracking in Real-Time Myocardial Contrast Echocardiography

Paeonol Protects Rat Heart by Improving Regional Blood Perfusion during No-Reflow

No-reflow phenomenon, defined as inadequate perfusion of myocardium without evident artery obstruction, occurs at a high incidence after coronary revascularization. The mechanisms underlying no-reflow is only partially understood. It is commonly caused by the swelling of endothelial cells, neutrophil accumulation, and vasoconstriction, which are all related to acute inflammation. Persistent no-reflow can lead to hospitalization and mortality. However, an effective preventive intervention has not yet been established. We have previously found that paeonol, an active extraction from the root of Paeonia suffruticosa, can benefit the heart function by inhibiting tissue damage after ischemia, reducing inflammation, and inducing vasodilatation. To further investigate the potential cardioprotective action of paeonol on no-reflow, healthy male Wistar rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R) injury (left anterior descending coronary artery was ligated for 4 h followed by reperfusion for 8 h), and I/R injury pretreated with paeonol at two different doses. Real-time myocardial contrast echocardiography was used to monitor regional blood perfusion and cardiac functions. Our data indicated that paeonol treatment significantly reduces myocardial infarct area and no-reflow area (n = 8; p < 0.05). Regional myocardial perfusion (A·β) and cardiac functions such as ejection fraction, stroke volume, and fractional shortening were elevated by paeonol (n = 8; p < 0.05). Paeonol also lowered the serum levels of lactate dehydrogenase, creatine kinase, cardiac troponin T, and C-reactive protein, as indices of myocardial injury. Paeonol exerts beneficial effects on attenuating I/R-associated no-reflow injuries, and may be considered as a potential preventive treatment for cardiac diseases or post-coronary revascularization in which no-reflow often occurs.

Resting Myocardial Contrast Echocardiography for the Evaluation of Coronary Microcirculation Dysfunction in Patients With Early Coronary Artery Disease

BACKGROUND

Coronary microcirculation dysfunction can occur in patients with chest pain suggestive of coronary artery disease (CAD). The present study aimed to determine the diagnostic value of resting myocardial contrast echocardiography (MCE) for early CAD with myocardial microcirculation dysfunction by evaluating the continuous imaging time, peak time, and peak intensity.

HYPOTHESIS

Resting MCE is an effective and noninvasive method for evaluation of coronary microcirculation dysfunction in patients with early coronary artery disease.

METHODS

The present study included 20 consecutive patients without obvious clinical evidence of early CAD and 20 healthy volunteers. Resting MCE was performed to evaluate the myocardial microcirculation perfusion, and the follow-up evaluation of myocardial microcirculation perfusion was performed with technetium 99 m 2-methoxy-isobutyl-isonitrile ((99m) Tc-MIBI) single-photon emission computed tomography (SPECT).

RESULTS

Peak intensity was significantly lower in patients with high risk of CAD than in controls (P < 0.0001). The peak time and continuous imaging time were significantly higher in patients with high risk of CAD than in controls (P < 0.0001). None of the 40 subjects experienced discomfort, such as cough and chest tightness, during the resting MCE procedure, and the heart rate and blood pressure showed no abnormalities during the entire procedure. SPECT imaging showed reversible myocardial perfusion reduction in 80% (16/20) of the patients with high risk of CAD. Abnormalities of heart rate and blood pressure and adverse reactions were noted during the process of SPECT examination.

CONCLUSIONS

Resting MCE is an effective and noninvasive method for detecting abnormalities of coronary microcirculation and can help in the clinical analysis, risk assessment, and treatment of early occult CAD.