Hironori Haruta

Development of Human‐Like Advanced Coronary Plaques in Low‐Density Lipoprotein Receptor Knockout Pigs and Justification for Statin Treatment Before Formation of Atherosclerotic Plaques

Background Although clinical trials have proved that statin can be used prophylactically against cardiovascular events, the direct effects of statin on plaque development are not well understood. We generated low‐density lipoprotein receptor knockout (LDLR −/−) pigs to study the effects of early statin administration on development of atherosclerotic plaques, especially advanced plaques. Methods and Results LDLR −/− pigs were generated by targeted deletion of exon 4 of the LDLR gene. Given a standard chow diet, LDLR −/− pigs showed atherosclerotic lesions starting at 6 months of age. When 3‐month‐old LDLR −/− pigs were fed a high‐cholesterol, high‐fat (HCHF) diet for 4 months (HCHF group), human‐like advanced coronary plaques developed. We also fed 3‐month‐old LDLR −/− pigs an HCHF diet with pitavastatin for 4 months (Statin Prophylaxis Group). Although serum cholesterol concentrations did not differ significantly between the 2 groups, intravascular ultrasound revealed 52% reduced plaque volume in statin‐treated pigs. Pathological examination revealed most lesions (87%) in the statin prophylaxis group were early‐stage lesions, versus 45% in the HCHF diet group (P<0.01). Thin‐cap fibroatheroma characterized 40% of the plaques in the HCHF diet group versus 8% in the statin prophylaxis group (P<0.01), intraplaque hemorrhage characterized 11% versus 1% (P<0.01), and calcification characterized 22% versus 1% (P<0.01). Conclusions Results of our large animal experiment support statin prophylaxis before the occurrence of atherosclerosis. Early statin treatment appears to retard development of coronary artery atherosclerosis and ensure lesion stability. In addition, the LDLR −/− pigs we developed represent a large animal model of human‐like advanced coronary plaque suitable for translational research.

Changes over time in echocardiographic variables and atrial electromechanical intervals after ablation for atrial fibrillation

Acute and mid‐term effects of ablation for atrial fibrillation (AF) on left atrial (LA) and left ventricular (LV) function and the atrial electromechanical interval are controversial.

Atrial tachycardia in a patient with arrhythmogenic right ventricular cardiomyopathy/dysplasia

We describe a 49‐year‐old woman with atrial tachycardia (AT) and arrhythmogenic right ventricular cardiomyopathy/dysplasia. Cardiac magnetic resonance images showed a markedly dilated right atrium and right ventricle. Electroanatomical mapping showed that the AT originated from the right atrial appendage.

Stabilization of atherosclerotic plaque by pitavastatin in Watanabe heritable hyperlipidemic rabbits: A serial tissue-characterizing intravascular ultrasound study.

BACKGROUND To examine the effects of pitavastatin on atherosclerotic plaque in Watanabe heritable hyperlipidemic (WHHL) rabbits using serial in vivo tissue-characterizing intravascular ultrasound. METHODS A total of 11 WHHL rabbits of 10-12 weeks of age were divided into two groups, control and pitavastatin-administered groups. A total of 29 atherosclerotic plaque segments from control group and 43 plaque segments from the pitavastatin group were serially imaged by 40MHz intravascular ultrasound in vivo with a tissue characterization software (iMAP™, Boston Scientific, Natick, MA, USA) at the baseline and the follow-up (16th week). RESULTS The level of low-density lipoprotein cholesterol was significantly decreased in pitavastatin group. During the follow-up period, plaque area was significantly increased in the control group, whereas it was not significantly changed in the pitavastatin group. The fibrotic, necrotic, and necrotic plus lipidic areas were significantly increased in the control group, while no significant change was revealed for tissue profile in pitavastatin group. The change in the percent areas of fibrotic and lipidic plus necrotic tissues were significantly different between the two groups especially in the superficial half portion of plaque. CONCLUSIONS These data indicate that pitavastatin could attenuate atherosclerotic plaque formation and that it could stabilize the plaque in WHHL rabbits. Considering the fact that these were observed even with a high follow-up level of cholesterol, these data might come from the pleiotropic effects of pitavastatin.

Impact of Oral Treatment on Physical Function in Older Patients Hospitalized for Heart Failure: A Randomized Clinical Trial.

Background Frailty is a characteristic of older patients with heart failure, who undergo functional decline during hospitalization. At present, continuous intravenous infusion of diuretics is widely used for the treatment of hospitalized patients with heart failure. In this prospective, randomized, open-label controlled trial, we tested whether an early switch from continuous intravenous infusion therapy to oral treatment with diuretics prevents functional decline in patients hospitalized for heart failure. Methods A total of 59 patients hospitalized for heart failure were randomized to either continuous intravenous infusion (n = 30) or oral medication (n = 29) within 48 h of admission. The primary outcome was the Barthel index, a universally utilized scale to assess the functional status of patients in their activities of daily living, assessed at 10 days. Secondary outcomes included the number of daily steps counted using pedometers and average hospital costs. Results Barthel index scores were significantly higher in the oral medication group than in the intravenous group (78.1 ± 20.8 vs. 59.6 ± 34.2, P = 0.029). The number of daily steps was significantly higher in the oral treatment group relative to the intravenous group (P < 0.001), and the average hospital costs were similar between the randomized groups. Multivariate analysis revealed that oral medication was a significant independent predictor of Barthel index score at day 10, and the number of daily steps was significantly associated with the patient’s functional outcome. Conclusions This trial showed that, in patients hospitalized for heart failure, oral medication increased functional independence during hospitalization compared with sustained continuous intravenous infusion, most likely because the release from the infusion line enabled the patients to be more mobile. Notably, these beneficial effects were achieved without increasing hospital costs.

Angioscopic differences of coronary intima between diffuse and focal coronary vasospasm: Comparison of optical coherence tomography findings

BACKGROUND Coronary artery vasospasm (CS) can be identified as either a diffuse type or focal type; however, the difference in endothelial characteristics between these spasm types remains unclear. The features of coronary intima associated with diffuse spasm and focal spasm using coronary angioscopy (CAS) were evaluated and the optical coherence tomography (OCT) findings were compared. METHODS CAS and/or OCT observational analysis was performed in 55 patients (mean age: 61.4 years, 31 men) who had acetylcholine-provoked CS (diffuse CS, 31 patients; focal CS, 24 patients). The yellowness of the intima, presence of thrombus in CAS, and intimal characteristics based on the OCT results were evaluated. RESULTS CAS showed more atherosclerotic yellow plaques at the focal spasm segment than at the diffuse spasm segment (p=0.032). Moreover, there were more thrombi at the focal spasm segment (p=0.039). In addition, OCT results revealed that the intima area, maximum intima thickness, and lipid content in the focal CS group were larger than the diffuse CS group (4.22±1.67mm2 vs. 3.45±2.36mm2; 0.71±0.29mm vs. 0.53±0.30mm; 55.9% vs. 32.0%, p<0.001, respectively). CONCLUSIONS These results indicate that the presence of atherosclerotic plaques at the spasm site is likely to be related to the occurrence of a focal vasospasm. This may support the difference of features between focal CS and diffuse CS and contribute to precise treatment for each spasm type.

A Case of Calcified Amorphous Tumor Found with Cerebral Infarction

A 47-year-old man with cerebral infarction and end-stage of kidney disease on hemodialysis was transferred to our hospital because of a suspicion of infective endocarditis. Although echocardiography revealed a high echoic mass on the mitral leaflet mimicking of vegetation, we finally diagnosed Calcified Amorphous Tumor (CAT) by clinical course and image findings. Because of lacking of prospective investigations despite lots of case reports, epidemiology, prognosis and appropriate treatment including surgical resection of CAT are still controversy.

The Spatial Distribution of Plaque Vulnerabilities in Patients with Acute Myocardial Infarction

Objective Although the plaque characteristics have been recognized in patients with acute myocardial infarction (AMI), the plaque spatial distribution is not well clarified. Using color-mapping intravascular ultrasound (iMAP-IVUS), we examined culprit lesions to clarify plaque morphology, composition and spatial distribution of the sites of potential vulnerability. Methods Sixty-eight culprit lesions in 64 consecutive AMI patients who underwent angiography and IVUS examinations before intervention were analyzed. Plaque morphology and composition were quantified with iMAP-IVUS. The spatial distribution of the sites of potential vulnerability was assessed with longitudinal reconstruction of the consecutive IVUS images. The plaque characteristics were also compared between ruptured and non-ruptured lesions, and between totally occlusive (TO) and non-TO lesions. Results The sites with maximum necrotic area (maxNA), maximum plaque burden (maxPB) and most severely narrowed (minimal luminal area, MLA) were recognized vulnerability. In the majority of cases, maxNA sites were proximal to the maxPB sites, and MLA sites were distal to the maxNA and maxPB sites. Ruptures usually occurred close to maxNA sites and proximal to maxPB and MLA sites. The average distance from the site of rupture to the maxNA site was 0.33 ± 4.04 mm. Ruptured lesions showed significant vessel remodeling, greater plaque volume, and greater lipidic volume compared to those of non-ruptured lesions. Both the length and plaque burden (PB) of TO lesions were greater than those of non-TO lesions. Conclusions Instead of overlapping on maxPB sites, most maxNA sites are proximal to the maxPB sites and are the sites most likely to rupture. Plaque morphology and composition play critical roles in plaque rupture and coronary occlusion.

3D Image Reconstruction of Histopathological Structure of Atherosclerotic Plaque Using a Novel Technique With Film Tomography

Pathology studies of atherosclerosis have contributed much to our understanding, but they are based mainly on cross-sectional views of the postmortem artery samples. Atherosclerosis is, however, a dynamic 3-dimensional (3D) pathological process and 3D imaging techniques such as intravascular

A case of typical atrial flutter causing unexpected advanced atrioventricular block despite lateral cavotricuspid isthmus ablation

Here, we report a case of a 69‐year‐old patient with paroxysmal atrial fibrillation and inducible typical atrial flutter who required catheter ablation. After pulmonary vein isolation, cavotricuspid isthmus ablation was performed. During ablation at a lateral site of the cavotricuspid isthmus, a spiky potential appeared at the distal electrode of the ablation catheter, and subsequently, a 2:1 atrioventricular (AV) block occurred. Radiofrequency (RF) delivery at the same site caused a similar phenomenon, implying that the spiky potential may reflect a slow pathway potential as an anatomical variant of the rightward extension of the AV node.