Evaluation of regional myocardial perfusion in methamphetamine abusers using real-time myocardial contrast echocardiography.

AIMS: To evaluate the feasibility of assessing regional myocardial perfusion using real-time myocardial contrast echocardiography (MCE) at rest for detecting coronary microcirculation abnormalities in methamphetamine abusers.Material and methods: Twenty-two male methamphetamine abusers (11 without chest pain, 11 with chest pain), free of ascertained coronary artery disease, were enrolled in this study. A control group of 22 age-matched male healthy participants was studied for comparison. Standard 2D, flow and tissue Doppler echo with measurements of cardiac morphologic and functional indicators,MCE with measurements of regional myocardial perfusion were performed, respectively. RESULTS: Compared to healthy participants, methamphetamine abusers had higher blood pressure, greater left ventricular mass index and more impaired diastolic function, with preserved cardiac sizes and systolic function. Methamphetamine abusers with chest pain had a faster heart rate than those without chest pain and healthy participants. MCE in methamphetamine abusers, especially with chest pain, had significant longer contrast agent arrival times, less functional capillary blood volumes, slower microvascular flow velocities and less myocardial perfusion than healthy participants (p<0.05). Moreover, along with the increases of dosage and duration of use (from group A to group C, group A: 1-2 g/day, <2 years; group B: 2-3 g/day, 2-5 years; group C: >3 g/day, >5 years) the reductions in the myocardial perfusion indices were more significant (p<0.01). The cutoff value with 5.1 dB2/s of the myocardial perfusion at the left ventricular apex had a sensitivity of 87.5%, specificity of 75.2% and accuracy of 81.9% for differentiating methamphetamine abusers from normal subjects. CONCLUSIONS: Real-time MCE can effectively detect coronary microcirculation abnormalities in methamphetamine abusers at rest and myocardial perfusion is significantly reduced in methamphetamine abusers. This finding may be involved in the occurrence and development of cardiac damage.

Coronary sinus flow is reduced in methamphetamine abusers: a transthoracic echocardiographic study.

To compare the coronary sinus flow among healthy participants, methamphetamine abusers without chest pain and those with chest pain. One hundred and eight methamphetamine abusers: 53 ones without chest pain, 55 ones with chest pain, free of ascertained coronary artery disease, were enrolled in this study. A control group of 50 age-matched male healthy participants was studied for comparison. Standard 2D, flow and tissue Doppler echo with measurements of cardiac morphologic and functional indicators, coronary sinus flow, and inferior vena cava (IVC) ultrasound with measurements of the IVC dimensions and their collapsibility index were performed, respectively. Compared to healthy participants, methamphetamine abusers had higher blood pressure, greater left ventricular mass index and more impaired diastolic function, with preserved cardiac sizes, systolic function and right atrial pressure. Methamphetamine abusers with chest pain had faster heart rate than those without chest pain and healthy participants. Coronary sinus flow was significantly less in methamphetamine abusers than in healthy participants (P < 0.05), and was extremely lower in those with chest pain than in healthy participants (about one-fourth) (P < 0.01). The area under the curve (AUC) of coronary sinus flow was 0.913 (0.864-0.962), and the cutoff value with 221.65 mL/min had sensitivity of 83.4%, specificity of 87.2% and accuracy of 85.2% for differentiating methamphetamine abusers from healthy participants. While the AUC of coronary sinus flow was 0.996 (0.989-1.003), and the cutoff value with 172.59 mL/min had sensitivity of 100%, specificity of 93.3% and accuracy of 96.5% for predicting methamphetamine abusers with chest pain. Coronary sinus flow is significant reduced in methamphetamine abusers, which is maybe a good indicator for indentifying methamphetamine abusers from normal population, and for predicting methamphetamine abusers with chest pain.

Findings on 3D speckle tracking echocardiography in asymptomatic methamphetamine abusers.

To detect potential cardiac abnormalities in asymptomatic methamphetamine abusers using three-dimensional speckle tracking echocardiography (3D STE). Fifty-three male methamphetamine abusers, free of cardiac symptoms/signs, were enrolled in this study. A control group of 53 age-matched male normal subjects was studied for comparison. Standard 3D, flow and tissue Doppler echo with measurements of left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), ejection fraction (LVEF), the ratio of the early to late diastolic transmitral filling velocity (E/A), the ratio of the early diastolic transmitral filling velocity to the early diastolic septal tissue velocity (E/E') and 3D STE with measurements of global area strain (GAS), global longitudinal strain (GLS), global circumferential strain (GCS) and global radial strain (GRS) were performed, respectively. These echocardiographic parameters were compared between methamphetamine abusers and normal subjects, and receiver operating characteristic curve (ROC) analysis was done to differentiating methamphetamine abusers from normal subjects. LVESV, LVEDV, LVEF, E/A, E/E' ratios and GRS were not significantly different between methamphetamine abusers and normal subjects (p > 0.05). However, GAS, GLS and GCS were significantly less in methamphetamine abusers than in normal subjects (p < 0.05). The areas under ROC (AUC) for GAS were greatest among all the 3D STE derived LV global strains (GAS vs. GLS, GCS and GRS, 0.95 vs. 0.76, 0.69 and 0.61, respectively). The cutoff value with - 30.3% of GAS had sensitivity of 91.8%, specificity of 91.6% and accuracy of 91.3% for differentiating methamphetamine abusers from normal subjects. The potential myocardial function abnormalities can be detected by 3D STE in asymptomatic methamphetamine abusers, and GAS is a good indicator for indentifying methamphetamine abusers from normal population, which can be used to screening and monitor methamphetamine abuse, detect subclinical LV dysfunction, predict potential methamphetamine-related cardiotoxicity, and to initiate early cardioprotective therapy before the onset of overt heart failure in time.

Reduction of Store-Operated Ca(2+) Entry Correlates with Endothelial Progenitor Cell Dysfunction in Atherosclerotic Mice.

The dysfunction of endothelial progenitor cells (EPCs) has been shown to prevent endothelial repair during the development of atherosclerosis (AS). Previous studies have revealed that store-operated calcium entry (SOCE) is an important factor in regulating EPC functions. However, whether this is also the mechanism in AS has not been elucidated. Therefore, we evaluated the role of SOCE in EPCs isolated from an atherosclerotic mouse model. Atheromatous plaques were more frequent in the aortas of ApoE(-/-) mice fed a high-fat diet for 16 weeks compared with controls, and the proliferative and migratory activities of atherosclerotic EPCs were significantly decreased. Accordingly, SOCE amplitude, as well as spontaneous or VEGF-induced Ca(2+) oscillations, decreased in atherosclerotic EPCs. These results may be associated with the downregulated expression of Stim1, Orai1, and TRPC1, which are major mediators of SOCE. In addition, eNOS expression and phosphorylation at Ser(1177), which are critical regulators of EPC function, were markedly reduced in the atherosclerotic EPCs. The impairment of eNOS activity could also be induced by using an SOCE inhibitor or by Stim1 gene silencing, indicating a link between the activities of eNOS and SOCE in AS. Furthermore, decreased SOCE function inhibited EPC proliferation and migration in vitro. In conclusion, our results showed that the reduction of SOCE induced EPC dysfunction during AS, potentially through downregulation of store-operated calcium channel (SOCC) components and impaired eNOS activity. Approaches aimed at reestablishing SOCE activity may thus improve the function of EPCs during AS.