Takashi Yoshitama

Chronic stent recoil plays an important role in restenosis of the right coronary ostium.

ObjectiveThe efficacy of coronary stenting of aorto-ostial atherosclerotic lesions is still unclear. We investigated the frequency and mechanism of stent restenosis at this particular lesion. MethodsFifty-five consecutive patients with 64 native aorto-ostial lesions in the right coronary artery (RCA, n=38) and the left main trunk (LM, n=26) were treated by conventional stenting. Determinants of angiographic restenosis were established. The mechanism of stent restenosis was evaluated using post-stenting and follow-up intravascular ultrasound (IVUS) findings. ResultsRestenosis was more frequent in the RCA than in the LM (50% compared with 19%, P<0.03) and determinants included diabetes mellitus (63% compared with 21%, P<0.03), calcium deposition (58% compared with 5%, P<0.003), smaller stent cross-sectional area (SA) (as demonstrated by post-stenting IVUS studies, 8.1±1.4 mm2 compared with 10.2±2.2 mm2, P<0.01), larger plaque burden (64±6% compared with 57±8%, P<0.03) and less circular expansion at the aorto-coronary junction. Serial IVUS examination was performed in 11 patients with restenosis of the right coronary ostium. The mean reduction in the SA was 21% at the aorto-coronary junction (6.4±1.9 mm2, P<0.003), whereas the SA at the distal edge was unchanged. Thirty-three per cent of late luminal loss was due to chronic stent recoil. ConclusionThese findings suggest that stenosis of the right coronary ostium is a high-risk lesion for stent restenosis. In addition to excessive intimal growth, chronic stent recoil might be an important etiologic factor at this particular location.

Molecular genetic, biochemical, and clinical studies in three families with cardiac Fabry's disease.

The variant form of Fabrys disease, called cardiac Fabrys disease, which has left ventricular hypertrophy as its main clinical manifestation is not uncommon. Because there has been no pedigree analysis in families with cardiac Fabrys disease, we performed gene analyses, enzyme assays, and cardiac evaluations in 3 distinct families with cardiac Fabrys disease. Gene analyses were performed in all 18 members of 3 families including 3 male probands. Five hemizygotes and 6 heterozygotes were identified. Plasma alpha-galactosidase A activity was measured in all 18 family members. Echocardiography and electrocardiography were performed in the 5 hemizygotes and in 5 of the 6 heterozygotes. The proband and 3 heterozygotes from a pedigree with a mutation in exon 6 of the alpha-galactosidase A sequence leading to a Met296Ile substitution showed a decrease in alpha-galactosidase A activity. In a separate pedigree, a proband and his hemizygous brother, with a mutation in exon 2 leading to a Glu66Gln substitution, had a decrease in alpha-galactosidase A activity, whereas 3 heterozygotes had normal values. In the third pedigree, a decrease in alpha-galactosidase A activity was observed in 2 hemizygotes who have a mutation in exon 1 leading to an Ala2OPro substitution. Although all 5 hemizygotes exhibited left ventricular hypertrophy on echocardiography, all 5 heterozygotes lacked this finding. Because plasma alpha-galactosidase A activity was normal in some heterozygotes with cardiac Fabrys disease, gene analysis is essential for an accurate diagnosis. Patients with cardiac Fabrys disease thus show an x-linked form of hypertrophic cardiomyopathy.

Heart Rate Recovery After Exercise Is a Predictor of Silent Myocardial Ischemia in Patients With Type 2 Diabetes

OBJECTIVE Slow heart rate recovery (HRR) predicts all-cause mortality. This study investigated the relationship between silent myocardial ischemia (SMI) and HRR in type 2 diabetes. RESEARCH DESIGN AND METHODS The study enrolled 87 consecutive patients with type 2 diabetes and no chest symptoms. They underwent treadmill exercise testing and single-photon emission computed tomography imaging with thallium scintigraphy. Patients with abnormal myocardial perfusion images also underwent coronary angiography. RESULTS SMI was diagnosed in 41 patients (47%). The SMI group showed slower HRR than the non–SMI group (18 ± 6 vs. 30 ± 12 bpm; P < 0.0001). HRR was significantly associated with SMI (odds ratio 0.83 [95% CI 0.75–0.92]; P = 0.0006), even after adjustment for maximal exercise workload, resting heart rate, maximum heart rate, rate pressure product, HbA1c, use of sulfonamides, and a history of cardiovascular disease. CONCLUSIONS HRR can predict SMI in patients with type 2 diabetes.

Relation of coronary plaque composition determined by 64-slice multidetector computed tomography in patients with suspected coronary heart disease.

Sixty-four-slice multidetector row computed tomography is a noninvasive method of assessing coronary artery stenosis and plaque composition. The aim of this study was to clarify the relation between plaque composition and coronary heart disease. Three hundred sixty consecutive patients and 1,085 plaques were evaluated using 64-slice multidetector row computed tomography. On axial or cross-sectional multiplanar reconstruction images, 3 regions of interest were randomly selected within each plaque. Soft plaques and calcified plaques were defined as having computed tomographic densities <50 and >130 Hounsfield units, respectively. The association between coronary risk factors and plaque composition was analyzed. The number of plaques and the mean computed tomographic density of plaques were significantly higher in men than in women (p = 0.002 and p = 0.04, respectively). Coronary plaques were more frequent in patients with stroke, diabetes, hypertension, and dyslipidemia than in patients without these conditions (all p values <0.001). Calcified plaques were more frequent in patients with hypertension (p = 0.02), and patients with calcified plaques also had significantly lower low-density lipoprotein cholesterol levels (p <0.001). Soft plaques were more frequent in patients with dyslipidemia (p <0.001). Patients with soft plaques had significantly higher low-density lipoprotein cholesterol levels (p = 0.02) and lower high-density lipoprotein cholesterol levels (p <0.001) than those without soft plaques. In conclusion, 64-slice multidetector row computed tomography is a useful noninvasive method for quantifying coronary plaques.