Background. Intravenous myocardial contrast echocardiography (MCE) has emerged as a novel method for assessment of myocardial blood volume (MBV), which changes in proportion to coronary stenosis severity at rest. The purpose of this study was to clarify the relation between phasic changes in MBV and the severity of coronary artery stenosis in humans.
Methods. We studied 58 patients with suspected coronary artery disease who underwent MCE with harmonic power Doppler imaging and continuous infusion of Levovist. Both end-systolic and end-diastolic images were obtained separately at every cardiac cycle. Regions of interest were placed at the mid-septum, and phasic changes in myocardial signal intensity (SI) were calculated as (SI at end-diastole)-(SI at end-systole).
Results. Twenty-four patients had significant coronary stenosis in the left anterior descending coronary artery (LAD), and 34 did not. The phasic changes in patients with LAD stenosis were significantly lower than that in patients without LAD stenosis (−0.5±1.2dB vs. 1.3±1.4dB, p<0.001). For the presence of >70% stenosis in LAD, the phasic changes <0.4 was the optimal cut-off value which provided sensitivity of 75%, specificity of 71% and accuracy of 73%.
Conclusions. Phasic changes in MBV assessed by MCE have the potential for detection of coronary artery stenosis in the clinical setting at rest.

View full abstract

Background. We investigated the effect of congestive heart failure (CHF) and pseudonormal (PN) hemodynamics on the TEI index in patients with left ventricular (LV) systolic dysfunction.
Methods. Study 1 included 12 patients with LV systolic dysfunction who were admitted because of CHF, and study 2 included 42 patients with LV systolic dysfunction whose ejection fraction (EF) was < 45%. Using conventional echo-Doppler methods, the following parameters were assessed: LV end-diastolic volume (LVEDV), LVEF, the ratio of early to late diastolic mitral inflow velocity (E/A), isovolumic contraction time (ICT), isovolumic relaxation time (IRT), and ejection time (ET). The TEI index was calculated as the sum of ICT and IRT divided by ET. In study 1, these parameters were compared between the acute decompensated and compensated stages. In study 2, the patients were divided into PN (E/A>1.2, n=26) and impaired relaxation (IR; E/A<0.8, n=16) groups based on the E/A ratio. The same parameters were compared between these two groups.
Results. Compared with acute decompensated stage in study 1, the mitral inflow profile changed from an E>A to E<A pattern, the LVEDV decreased, and the LVEF increased in the compensated stage. There were no changes in the ET or ICT, a significant prolongation of the IRT, and a significant increase in the TEI index. In study 2, there were no differences in age, LVEDV, LVEF, ET, or ICT between the PN and IR groups. However, the IRT was significantly prolonged and the TEI index was significantly increased in the IR group compared to the PN group. The TEI index best linearly correlated with IRT among various time intervals.
Conclusions. The TEI index showed a paradoxically small value due to a shortened IRT in the acute decompensated stage compared with the compensated stage of CHF. Such pseudonormal phenomena should be taken into consideration in the evaluation of LV function by the TEI index in patients with LV systolic dysfunction.

View full abstract

Background. Chest pain, ST segment elevation and slow flow are recognized as the complications of percutaneous transluminal coronary rotational atherectomy (PTCRA). But the relation between these complications and microvascular dysfunction remains unknown. We assessed the impact of PTCRA on coronary microvascular function with myocardial contrast echocardiography (MCE).
Methods. Consecutive 36 patients with stable effort angina underwent PTCRA using the continuous infusion of verapamil into the target vessel. MCE was performed with the intracoronary injection of sonicated microbubbles before, during or shortly after, and after PTCRA procedure. We measured baseline-subtracted peak intensity (256 gray scales) in the risk zone and in the normal zone, and calculated the ratio of the former to the latter (PI ratio). We divided the patients into two groups based on the presence or absence of ST elevation during PTCRA, group-A (n=20) = present and group-B (n=16) = absent.
Results. Before PTCRA, there was no difference in PI ratio between two groups (A vs. B; 0.85±0.32 vs. 0.77±0.23). During or shortly after PTCRA, PI ratio in group-A was significantly lower than that in group-B (0.29±0.26 vs. 0.90±0.19, p<0.05), but only 5 patients of group-A showed angiographical slow flow. In group-A, ST elevation resolved to baseline 15 ± 9 min later, and PI ratio increased to baseline level at this moment (0.83±0.28).
Conclusions. MCE study reveals that PTCRA produces microvascular dysfunction much more frequently than expected from angiographical findings. This microvascular dysfunction was not fully protected by verapamil, but it is transient and myocardial flow quickly recovers to the baseline level.

View full abstract

The clinical usefulness of intraoperative epicardial echocardiography in a patient with post-infarction angina complicated by a coronary-pulmonary artery fistula (CPAF) with aneurysmal change was reported. Epicardial echocardiography clearly showed feeding arteries to the fistula in the myocardium, which was not revealed by visual inspection, palpation, or transesophageal echocardiography. The patient was received off-pump coronary artery bypass grafting concomitant with aneurysmectomy. The feeding arteries were dissected easily using an ultrasonic scalpel and successfully ligated. The flow in the aneurysm disappeared immediately and aneurysmectomy was performed without bleeding. Intraoperative epicardial echocardiography was useful method during off-pump resection of CPAF.

View full abstract