Toshihiro Kawasaki

Direct Measurement of Wall Stiffness for Carotid Arteries by Ultrasound Strain Imaging

OBJECTIVE The elastic properties of the carotid arterial wall have not been directly characterized in the clinical setting. Strain rate (SR) imaging is a newly developed echocardiographic method developed for imaging the tissue motion of the myocardium. The purpose of this study was to directly estimate the elastic properties of the carotid artery by using SR imaging in patients with coronary artery disease (CAD). METHODS A total of 135 patients with CAD, 15 age-matched controls, and 35 young healthy subjects had a carotid ultrasound examination for measuring the values of SR and strain of the carotid artery. The intima-media thickness and distensibility coefficient of the carotid artery were estimated. RESULTS Age and Framingham risk score were significantly related to SR and strain, respectively (r = 0.62-0.67, all P < .001). These strain measurements were significantly correlated with distensibility coefficient and intima-media thickness, respectively (r = 0.30-0.56, all P < .001). Similar values of the areas under the receiver operating characteristic curves were obtained among Framingham risk score (0.70 +/- 0.05), SR (0.67 +/- 0.05), and strain (0.73 +/- 0.05). CONCLUSION This study demonstrated that the elastic properties of the carotid artery wall were directly characterized by using SR imaging in patients with CAD.

Pocket-Sized Echo for Evaluation of Mitral and Tricuspid Regurgitation

Advances in electronic miniaturization and digital techniqueshave resulted in the advent of portable transthoracic echocar-diography (pTTE) imaging devices in the area of echocardiog-raphy. A pocket-sized pTTE imaging device that has colorDoppler imaging capability has been recently introduced intoclinical practice. This study aimed to examine the feasibilityand accuracy of the pocket-sized pTTE in the assessment ofthe severity of mitral regurgitation (MR) and tricuspid regur-gitation (TR).One hundred and eighty-six consecutive patients (ages 66 19 years; 107 male) underwent standard transthoracic echo-cardiography (sTTE) and pTTE. Initially, pTTE was per-formed by a well-trained sonographer for 121 patients. For thelater 65 patients, pTTE was examined by a less experiencedsonographer who had 6 months of experience in echocardiog-raphy, with the number of TTE examinations compatible withAmerican Society of Echocardiography training level 1 (1).These sonographers were blinded to sTTE results and allclinical information.This study was approved by the ethics committees of OsakaEkisaikai Hospital and Okayama University. Pocket-sized pTTEwas performed using the Vscan (GE Medical Systems, Milwau-kee,Wisconsin).Theapical4-chamberviewbythecolorDopplerimages was obtained with sTTE and pTTE, respectively. Theratio of regurgitant jet area to atrial area was then calculated forMR (%MR) and TR (%TR). The severity of regurgitation wasgraded as mild if it occupied 20%, moderate if between 20%and 34%, and severe if 34% in TTE examination.Linear regression analysis was used for the correlation ofvariables of interest. Differences were considered significant atp 0.05.DifferencesbetweensTTEandpTTEresultswerealsocompared with the mean value obtained by sTTE and pTTEusing the Bland-Altman method, with the limits of agreementdefined as 2 SD of the difference between the 2 methods.Echocardiographic measurements were completed for sTTEand pTTE in all patients (feasibility 100%). In the examinationby the well-trained sonographer, there were excellent correlationsin MR jet area, left atrial area, %MR, TR jet area, right atrialarea, and %TR between sTTE and pTTE (r 0.89 to 0.96, p 0.001). Also, there were small systematic differences with closelimits of agreement between sTTE and pTTE measurements,respectively: 20.2 cm

Aromatherapy alleviates endothelial dysfunction of medical staff after night-shift work: preliminary observations

Night-shift work causes mental stress and lifestyle changes, and is recognized as a risk of cardiovascular diseases associated with impaired endothelial function. Aromatherapy is becoming popular as a complementary therapy that is beneficial for mental relaxation. The purpose of this study was to investigate the effect of aromatherapy on the endothelial function of medical staff after night-shift work. This study consisted of 19 healthy medical personnel (19 men, mean age 32±7 years), including 11 physicians and 8 technicians. Aromatherapy was performed for 30 min by inhalation of the essential oil of lavender. Flow-mediated dilation (FMD) of the brachial artery was measured three times in each subject: on a regular workday, and after night-shift work before and immediately after aromatherapy. A control study was performed to assess the effect of a 30-min rest without aromatherapy. The mean value of sleep time during night-shift work was 3.3±1.3 h. FMD after night-shift work was lower than on a regular workday (10.4±1.8 vs. 12.5±1.7%, P<0.001), which improved after aromatherapy (11.8±2.5%, P=0.02 vs. before aromatherapy). FMD was stable in the control study (10.1±1.9 vs. 10.1±2.2%, P=0.9). This study demonstrated that night-shift work impaired endothelial function in medical staff, an effect that was alleviated by short-term aromatherapy.

Transnasal transesophageal echocardiography in the detection of left atrial thrombus

BACKGROUND The widespread use of transesophageal echocardiography (TEE) is limited by disadvantages, including patient intolerance and increased medical costs. We aimed to investigate the feasibility and safety of transnasal TEE in the detection of possible embolic sources in patients with atrial fibrillation (AF) and/or stroke, using an ultrathin TEE probe. METHODS Sixty-two patients with AF and/or stroke underwent transnasal TEE without conscious sedation. The presence or the absence of the following parameters was evaluated: left atrial (LA) thrombus; LA spontaneous echocardiographic contrast; intraatrial shunts; and aortic plaque. RESULTS The insertion of a TEE probe was successful in 52 (84%) patients. TEE found LA thrombus in 10 (19%) patients and other embolic sources in 4 (8%) patients. Two (4%) patients had mild epistaxis. CONCLUSIONS This study demonstrated that the use of transnasal TEE was feasible and safe in the detection of LA thrombus in patients with AF and/or stroke.

Circadian variation in coronary flow velocity reserve and its relation to α1-sympathetic activity in humans

BACKGROUND The circadian change in coronary microvascular function has not been directly assessed in human beings. Recent advances in transthoracic Doppler echocardiography (TTDE) provide noninvasive, physiological assessment of coronary flow velocity reserve (CFVR). METHODS This study consisted of 20 young healthy subjects (24 ± 2 years, 20 men) who underwent CFVR examinations at 3 different times; early morning (6AM), late morning (11AM) and late evening (10PM). The flow velocity in the distal portion of the left anterior descending coronary artery was measured with TTDE at baseline and during adenosine infusion to calculate CFVR. These examinations were repeated with the intake of α1-blocker (prazosin 1mg) on the other day. RESULTS CFVR showed a circadian variation with an increase from the early morning to the late morning, following a decrease to the late evening thereafter (4.4 ± 0.9 at 6AM; 5.2 ± 1.3 at 11AM; 4.2 ± 1.1 at 10PM, p<0.001). In the study with α1-blocker, CFVR was comparable between the early morning and the late morning, whereas CFVR in the late evening was lower than those in other 2 time points (5.0 ± 1.1 at 6AM; 4.9 ± 0.9 at 11AM; 4.3 ± 0.9 at 10PM, p<0.001). CONCLUSIONS This study demonstrates that CFVR has a circadian variation in humans, with an increase from the late evening to the late morning. Adding α1-blocker ameliorated CFVR only in the early morning, indicating that α1-sympathetic activity plays a heterogeneous and important role in the circadian change of CFVR in humans.

WHOLE BODY PERIODIC ACCELERATION IMPROVES CORONARY MICROCIRCULATION IN HEALTHY SUBJECTS AND PATIENTS WITH CORONARY ARTERY DISEASE

Background: The whole body periodic acceleration (WBPA) system has recently been developed as a “passive exercise” device by providing increased pulsatile shear stress for improvement of endothelial function. This study aimed to investigate the acute effect of WBPA on coronary flow reserve (CFR) through transthoracic Doppler echocardiography (TTDE) in healthy subjects and patients with coronary artery disease (CAD).