Satoshi Kibira

Pitavastatin Inhibits Upregulation of Intermediate Conductance Calcium-Activated Potassium Channels and Coronary Arteriolar Remodeling Induced by Long-Term Blockade of Nitric Oxide Synthesis

We have reported that intermediate conductance Ca2+-activated K+ channels (ImK) showed augmented expression in angiotensin II (AII) type 1 receptor-dependent manner in post-ischemic rat heart. ImK has tyrosine phosphorylation sequence in the C-terminus and motifs for NFĸB and AP1 in the promoter. While statin inhibits AII-mediated vascular remodeling via anti-inflammatory effect independent of cholesterol lowering. To test the possible effect of statin on expression of ImK, Wistar-Kyoto rats received L-nitro-arginine methyl ester (LNAME: 1 mg/ml in drinking water) for 4 weeks in group L. While in L+P group, rats received both LNAME and pitavastatin (PTV: 1 mg/kg/day in drinking water). Temporal profile of ImK mRNA was examined by RT-PCR using specific primers for ImK. Results: Long-term LNAME administration produced significant hypertension and resulted in marked microvascular remodeling characterized by medial thickening and perivascular fibrosis of coronary arterioles (100–200 µm in diameter). RT-PCR revealed significant up-regulation of ImK mRNA with two distinct peaks in L group in the early phase (days 3–7) and the late phase (4 weeks). PTV partially inhibited a rise in systolic blood pressure, but completely abolished the first peak of ImK upregulation (0.76 ± 0.04 vs. 3.96 ± 1.43 folds at day 7, p < 0.001). Co-treatments with PTV also significantly inhibited medial thickening and perivascular fibrosis. These findings indicate that statin inhibits microvascular remodeling induced by chronic inhibition of NO synthesis through the action independent of cholesterol lowering.

Does Central Venous Pressure Reflect the Circulating Blood Volume for the Decrement of Compliance Just After Esophagectomy

Abstract: This study investigates whether the pressure parameters obtained from the Swan-Ganz catheter (SGC) accurately reflect the circulating blood volume just after en bloc resection of the thoracic esophagus with regional lymph node dissection. It is well known that this operation induces severe hemodynamic changes and although the pressure parameters obtained from the SGC are an accepted means of monitoring circulating blood volume, we have often experienced a discrepancy between the SGC data and the clinical state. We examined the pressure parameters and diameter of the inferior vena cava (IVC) and left ventricle (LV), and the central venous compliance using SGC and echocardiography in ten patients who underwent esophagectomy for esophageal cancer. The central venous pressure, pulmonary arterial mean pressure, and pulmonary artery wedged pressure were significantly increased just after the operation compared with the preoperative levels, while the diameters of the IVC and LV decreased just after the operation. The compliances of the IVC decreased significantly just after the operation. The hemodynamic shift to the third space after esophagectomy induces decrement of the compliances of IVC. As the CVP does not always reflect the circulating blood volume, measuring the diameter of the IVC using echocardiography is extremely useful for monitoring circulating blood volume just after esophagectomy.

Validity of the right ventricular Doppler index for assessment of severity of congestive heart failure in patients with dilated cardiomyopathy

SummaryThis study was designed to clarify the validity of Doppler indices for assessment of the severity of congestive heart failure in patients with dilated cardiomyopathy. Left ventricular (LV) and right ventricular (RV) Doppler indices, defined as the sum of isovolumic contraction time and relaxation time divided by the ejection time, were obtained in 30 normal subjects and 35 patients with ischemic or idiopathic dilated cardiomyopathy. We analyzed the correlation between New York Heart Association (NYHA) functional class, right-sided cardiac pressure, and the Doppler indices. Patients with dilated cardiomyopathy revealed significantly higher LV and RV Doppler indices than normal subjects; however, the LV Doppler index did not correlate significantly with NYHA functional class or right-sided cardiac pressure. On the other hand, the RV Doppler index correlated significantly with NYHA functional class (rs = 0.83,P < 0.001), pulmonary capillary wedge pressure (r = 0.80,P < 0.001), pulmonary artery systolic pressure (r = 0.81,P < 0.001) and pulmonary artery diastolic pressure (r = 0.77,P < 0.001). Both RV isovolumic contraction and relaxation time also correlated significantly with right-sided cardiac pressure. In 12 patients who improved from NYHA III–IV to I–II after treatment, the RV Doppler index decreased from 0.84 ± 0.25 to 0.33 ± 0.10 (P < 0.001), while the LV Doppler index did not change significantly (0.72 ± 0.27 to 0.68 ± 0.23,P = 0.53). These results suggest that the RV Doppler index is useful for assessment of the severity of congestive heart failure in patients with dilated cardiomyopathy.

Clinical importance of AaDo2 and pulmonary artery pressure as predicted by pulsed Doppler echocardiography at bedside in diagnosing pulmonary embolism

The authors evaluated clinical importance of alveolar-arterial PO2 difference (AaDO2) and pulmonary artery pressure (PAP) estimated by pulsed Doppler echocardiography in 31 patients with pulmonary embolism (PE). Echocardiographic estimates from flow velocity patterns in the right ventricular outflow tract showed significant correlation with actual measurements obtained by right cardiac catheterization. Furthermore, PAP as obtained by pulsed echocardiography was significantly higher in acute massive and recurrent multiple groups in comparison with the acute submassive group. AaDO2 was greatest in the acute massive group, followed by the recurrent multiple group, and then by the acute submassive group. These results suggest that analyses of AaDO2 and the echocardiographic estimation of PAP at bedside are successful in the diagnosis and classification of PE.

Papillary fibroelastoma in the left ventricular outflow tract.

usually arises from the aortic valve or the mitral valve. We report here an extremely rare case of this tumor arising from the interventricular septum in the left ventricular outflow tract (LVOT). The patient was a 71-year-old man with a history of diabetes mellitus and hypertension since 1987. He visited our hospital to receive a regular medical check-up. He had experienced a syncope attack in 1995, when magnetic resonance imaging (MRI) images revealed multiple lacunar infarctions, and since then he had been treated with aspirin. In 1995, transthoracic echocardiography (TTE), performed to detect the embolic focus, had revealed no abnormalities. On his visit to our hospital, electrocardiogram (ECG) revealed a slightly depressed ST on V5 and V6, and these changes progressed gradually, which prompted us to admit him. Physical examination and admission laboratory data showed no abnormality, except for mild hepatic dysfunction. His blood pressure was 141/86mmHg, and his pulse rate was 80/min and regular. TTE, using an SSD 6500 ultrasound scanner (Aloka, Tokyo, Japan) and 1.88-MHz harmonic imaging, revealed a small soft moving 7-mm mass with a frond-like surface attached to the interventricular septum just below the aortic valve in the LVOT. Transesophageal echocardiography (TEE), with a conventional 6-MHz sector transducer, provided us with more detailed information about the tumor in the LVOT. It showed that the tumor had a very fine pedicle (Fig. 1), and that the aortic valve was slightly sclerotic but the mitral valve was not. Neither valve had any significant regurgitation. Angiographic examination was performed, with care taken not to insert the catheter into the LVOT. It revealed a mild spastic change in the right coronary artery (following intra-coronary injection of acetylcholine). This was the only abnormality we encountered at the level of the coronary arteries.Tumor resection was performed to prevent the occurrence of tumor embolization, under the presumed diagnosis of LV tumor, and surgery confirmed that it was an LV tumor with a frond-like surface. Microscopically, the tumor was coated with a layer of endothelial cells and was rich in elastic fibers in the center (Fig. 2). The patient was doing well 8 months after the operation, with no signs of tumor recurrence. J Med Ultrasonics (2006) 33:119–120

Reduction of ST elevation in repeated coronary occlusion model depends on both altered metabolic response and conduction property

The aim of this study was to elucidate the mechanisms of altered electrical response to ischemia in repeated coronary occlusion model. To test its dependence on metabolic response, extracellular K+ concentration (eKC), myocardial pH and PCO2 were simultaneously measured with epicardial ECG during three consecutive 4 min of left anterior descending coronary artery (LAD) occlusion separated by 15 min of reperfusion in canine hearts. ECG changes induced by infusion of high K+-buffer (10 mM) into the coronary arterial bed via carotid artery-LAD bypass (referred to as high K+-challenges: HKC) were also tested prior to (the first HKC), and during each reperfusion period (the second to the fourth HKC). ST elevation was significantly reduced in subsequent occlusions (3.14 +/- 0.48 and 2.98 +/- 0.47 mV in the second and third occlusion, both P<0.05, compared to 4.91 +/- 0.78 mV in the first). This was accompanied by significant attenuation of the changes in eKC, tissue pH and PCO2. ST elevation induced by HKC also significantly reduced after repeated occlusion (4.09 +/- 0.79 mV in the fourth HKC vs. 5.64 +/- 0.68 mV in the first, P<0.05) in spite of the identical changes in eKC during HKC. This progressive decrease in ST changes by HKC was rather consistent with augmented conduction delay (86.4 +/- 7.1% increase in activation time in the fourth vs. 54.3 +/- 3.4% in the first, P<0.01). These findings indicate that repeated ischemia induces altered electrical response to subsequent ischemia based on both attenuated metabolic response and altered conduction property.

Validity of Ultrasound Lung Comets for Assessment of the Severity of Interstitial Pneumonia: Ultrasound Lung Comets in Interstitial Pneumonia

Ultrasound (US) lung comets are often observed in patients with interstitial lung disease or congestive heart failure, but few studies have explored the clinical importance of US lung comets in patients with the former condition. We explored whether the US lung comet number could be used to assess the severity of interstitial pneumonia.