Chihiro Suzuki

Increase in circulating endothelial progenitor cells after aortic aneurysm repair

Rapid endothelialization of prosthetic vessels is essential to avoid fatal complications. We hypothesized that there may be mobilization of endothelial progenitor cells (EPCs) in patients who received aortic aneurysm repair, and measured the number of CD34-expressing EPCs (CD34+ cells) in these patients. Blood samples were taken preoperatively, 6, 24, and 48 h, and 7 days after surgery in 13 patients with aortic aneurysm. Samples were also obtained from ten age-matched control subjects. The number of CD34+ cells in the peripheral blood was quantified by flow cytometry. The levels of serum vascular endothelial growth factor (VEGF) were measured using an enzyme-linked immunosorbent assay kit. Baseline CD34+ cell counts in the peripheral blood showed a tendency to be lower in patients with aortic aneurysm compared with healthy control subjects. The number of CD34+ cells did not change over 48 h after aortic aneurysm repair; however, it had doubled by the 7th day. On the other hand, the baseline serum VEGF levels did not differ between the patients and control subjects. The VEGF levels increased gradually after vascular repair with a significant elevation after 48 h, which was followed by an increase in CD34+ cell counts. In conclusion, the circulating CD34+ cell counts and serum VEGF levels are increased after vascular prosthesis replacement in patients with aortic aneurysm, which might contribute to the rapid endothelialization of prosthetic vessels.

Endomyocardial biopsy in a patient with hemorrhagic pheochromocytoma presenting as inverted Takotsubo cardiomyopathy.

A 29-year-old female patient presented with shock and dyspnea due to heart failure and pulmonary edema. Echocardiography indicated excessive contraction limited to the left ventricular apex and akinesis of the basal and middle ventricle, which were confirmed by emergency left ventriculography. The finding was diagnostic of inverted Takotsubo cardiomyopathy. An abdominal computed tomography scan showed a tumor in the left adrenal gland with a central low-density area, and the plasma and urinary catecholamines were strikingly elevated. Taken together, these findings suggested the presence of a hemorrhagic pheochromocytoma. A myocardial biopsy in the very acute stage on the day of admission revealed neutrophilic infiltration and contraction-band necrosis, which was indistinguishable from the previously reported pathology in the acute phase of idiopathic Takotsubo cardiomyopathy without pheochromocytoma. The diagnosis of pheochromocytoma in this case was confirmed 7 weeks later by surgical removal of the left adrenal gland with massive hemorrhage at the center of the pheochromocytoma. The marked similarity of the endomyocardial pathology between this case and cases with idiopathic Takotsubo cardiomyopathy strongly points to catecholamine excess as a common causality for Takotsubo cardiomyopathy with or without pheochromocytoma.

The site of mitral valve prolapse is a predictor of atrial fibrillation

P veins contain muscle fibers connected to the left atrium. These muscle fibers may be electrically active and serve the source of atrial tachyarrhythmia. Compatible with this hypothesis, a more recent study demonstrated that all 4 pulmonary veins might serve as the source of focal atrial fibrillation (AF). The direction of mitral regurgitation (MR) flow in patients with mitral valve prolapse (MVP) is unusual. However, the mechanisms causing AF in patients with MVP have not been fully investigated. In this study, we investigated whether the direction of MR flow in the left atrium of patients with MVP plays an important role in the prevalence of AF and tested the hypothesis that the site of MVP predicts AF. • • • From January 1992 to December 1999, 118 adult Japanese patients (69 men, 49 women, mean age 50 18 years) with echocardiographic documentation of MVP, who were either admitted to our hospital or were outpatients, were enrolled in this study. Eightysix of 118 patients had floppy valves. Criteria for exclusion from the study were congenital heart disease, Marfan’s syndrome, rheumatic heart disease, coronary artery disease, significant aortic stenosis, aortic regurgitation, cardiomyopathy, lone AF, and paroxysmal AF. No patient was taking any drugs (i.e., diuretic or antiarrhythmic drugs). We performed electrocardiography and echocardiography before medical and surgical treatment, and evaluated the clinical characteristics. Chronic AF was defined as AF documented by electrocardiography on 2 occasions on at least 2 visits to the outpatient clinic or the hospital 6 weeks apart. This study was approved by our institutional human investigations committee, and written informed consent was obtained from all patients before participation. M-mode, 2-dimensional, and color Doppler transthoracic echocardiography were performed in all patients with a Toshiba 160A system (Toshiba Medical Systems Co. Ltd, Tokyo, Japan) or a Hewlett-Packard SONOS 2500 system (Hewlett Packard, Palo Alto, California) with a 2.5MHz transducer. The left atrial diameter, left ventricular end-diastolic dimension, and left ventricular end-systolic dimension were determined by M-mode echocardiography. Fractional shortening of the left ventricle was determined with the M-mode echocardiogram in the standard manner. Echocardiographic morphologic characteristics of the mitral leaflets were estimated from images obtained from the parasternal longand short-axis views, and apical 4-chamber and long-axis views. Two-dimensional echocardiographic evidence of prolapsed leaflets was defined as a superior protrusion of the mitral leaflets into the left atrium, crossing the plane of the mitral annulus, with the coaptation point of the leaflets remaining at or superior to the mitral annular plane during systole. The site of MVP was assessed by 2-dimensional and color Doppler echocardiography. MVP was located at 6 sites: 3 anterior mitral leaflet sites (anterior commissural site, middle site, posterior commissural site) and 3 posterior mitral leaflet sites (medial scallop, middle scallop, lateral scallop). The involved site of scallop was determined by 2 different, independent observers and by the same observer on repeated assessment. The severity of MR was estimated by color Doppler echocardiography with a 2.5-MHz transducer. The degree of MR was assessed in terms of the distance in the left atrium reached by regurgitant flow from the mitral valve orifice, the maximum regurgitant jet area expressed as a percentage of the left atrium area, and the proximal isovelocity surface area visible in any view. MR was classified as trivial, mild, moderate, or severe. In this echocardiographic study, some patients were withdrawn because of suboptimal technical quality. Patients with MVP in 2 sites were excluded from the study, because leaks often include several scallops of the posterior leaflets. The clinical variables were age, sex, history of hypertension, current cigarette smoking, diabetes mellitus, and hypercholesterolemia. Hypertension was defined as a systolic blood pressure of at least 140 mm Hg or a diastolic blood pressure of at least 90 mm Hg From the Department of Cardiology and Community and Family Medicine, Jichi Medical School, Minamikawachi-Machi, Tochigi, Japan. This study was supported in part by a Research Grant 12670686 from the Ministry of Education, Science and Sports, Tokyo, Japan. Dr. Yamamoto’s address is: Department of Cardiology, Jichi Medical School, Minamikawachi-Machi, Tochigi, Japan 329-0498. E-mail: kyamamoto@jichi.ac.jp. Manuscript received February 25, 2001; revised manuscript received and accepted May 18, 2001. TABLE 1 Patient Characteristics

Diagnostic advantage of stress computed tomography myocardial perfusion over single-photon emission computed tomography for the assessment of myocardial ischemia

BACKGROUND This study compared adenosine stress computed tomography myocardial perfusion (CTP) with single-photon emission computed tomography (SPECT) in the diagnosis of functionally significant coronary artery stenosis using fractional flow reserve (FFR) as reference standard. METHODS We included a total of 93 coronary arteries from 31 patients in whom at least one vessel with ≥50% stenosis was detected with computed tomography coronary angiography. All patients underwent both SPECT and adenosine stress CTP, followed by invasive coronary angiography (ICA) and FFR. Diagnostic accuracy between CTP and SPECT was compared according to positive findings of either ≥99% stenosis on ICA or FFR ≤0.8. RESULTS Among 78 vessels eligible for the quantitative analyses, significant coronary artery disease (CAD) was diagnosed in 22 vessels of 19 patients. Comparison of CTP vs. SPECT for sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy in detecting significant CAD were 59% vs. 18%, 96% vs. 93%, 87% vs. 50%, 86% vs. 74%, and 86% vs. 72%, respectively. CONCLUSIONS CTP demonstrated a significant diagnostic advantage over SPECT in the identification of significant CAD, especially in terms of sensitivity and PPV. Adenosine stress CTP is useful for the noninvasive diagnosis of functionally significant CAD.