Masahiko Kanna

Local delivery of single low-dose of C-type natriuretic peptide, an endogenous vascular modulator, inhibits neointimal hyperplasia in a balloon-injured rabbit iliac artery model

C-type natriuretic peptide (CNP) is an endogenous vascular modulator. In addition to vasodilation, CNP exerts multifunctions including anti-thrombus and anti-proliferation actions against vascular smooth muscle cells and myofibroblasts. Therefore, CNP is a potential therapeutic agent for the prevention of restenosis following angioplasty. The current study investigated whether local delivery of CNP, even at microgram levels about three orders of magnitude lower than doses (high milligram levels) used for systemic administration in the previous study, attenuates neointimal hyperplasia. The rabbit iliac artery was denuded, and then CNP (100 &mgr;g, n = 5) or control vehicle (n = 5) was administered locally over 20 min, via a local drug delivery catheter. During drug delivery, blood pressure was monitored with a high-fidelity micromanometer catheter. There was no significant decrease in arterial pressure immediately after the CNP administration. Four weeks after the treatment, computer-assisted morphometric analysis revealed significant reduction in the intimal area (CNP 0.44 ± 0.27 versus control 0.96 ± 0.20 mm2, p < 0.01), but no changes in the medial area (CNP 0.93 ± 0.23 versus control 0.79 ± 0.29 mm2, p = NS). This resulted in a significant decrease in the ratio of the intimal area to the medial area in CNP-treated vessels compared with control vessels (CNP 0.45 ± 0.26 versus control 1.40 ± 0.66, p < 0.05). Local delivery of a single low dose of CNP effectively inhibits neointimal hyperplasia with a minimal likelihood of compromising hemodynamics. Considering its multipotent actions and its role as an important regulator of the vascular system, this treatment may have a therapeutic advantage for clinical use.

Usefulness of serum troponin T levels on day three or four in predicting survival after acute myocardial infarction

The appearance of serum troponin T (tn-T) on day 1 after acute myocardial infarction (AMI) strongly depends on coronary reperfusion. In contrast, the kinetics of tn-T release after day 1 after AMI are unaffected by the reperfusion status, and reflect the degradation of myofilaments in irreversibly damaged cells. However, it is not known whether serum tn-T levels after day 1 after AMI can be used to predict the long-term outcome. The purpose of this study was to elucidate the prognostic value of determining the tn-T level on day 3 or 4 after AMI. Serum tn-T levels on day 3 or 4 after AMI were measured in 121 patients (92 men and 29 women, mean age 65 years). Mean follow-up period was 526 days. There were 12 deaths (9 cardiac and 3 noncardiac) during the follow-up period. By Kaplan-Meier analysis, patients with tn-T levels higher than the median level (6.9 ng/ml) had a significantly higher mortality rate than those with submedian levels (p <0.01). By multivariate Cox proportional-hazards regression analysis, the serum tn-T level was an independent predictor of the long-term outcome after AMI (p <0.01). Futhermore, in patients with a first AMI, the serum tn-T level exhibited a significant negative linear correlation with left ventricular ejection fraction assessed 4 weeks after AMI (r = -0.48, p <0.001). Increased serum tn-T levels on day 3 or 4 after AMI are a powerful noninvasive predictor of poor long-term prognosis, reflecting residual left ventricular function after AMI.

CARDIAC INVOLVEMENT IN EOSINOPHILIC GRANULOMATOSIS WITH POLYANGITIS

Eosinophilic granulomatosis with polyangitis (EGPA) is a rare systemic vasculitis associated with bronchial asthma and hypereosinophilia. There were few reports organized EGPA in Japanese. We evaluated consecutive 133 EGPA patients, who had cardiac involvement (CI group; n=51, 38.3%) or not (Non CI

Long-Term Survivor With Pulmonary Veno-Occlusive Disease

A 51-year-old woman was admitted to our hospital because of shortness of breath. Her mean pulmonary artery pressure was 52 mm Hg, and idiopathic pulmonary artery hypertension was diagnosed. She received beraprost sodium, imidapril, warfarin, and home-based oxygen therapy. At 67 years of age, dyspnea on effort worsened to New York Heart Association functional class III. The plasma level of brain natriuretic peptide was 57 pg/mL. Transthoracic echocardiography showed an enlarged right ventricle, severe tricuspid regurgitation, and a large pericardial effusion. At 68 years of age, she was urgently admitted to our hospital because of severe dyspnea at rest. A chest x-ray showed bilateral pulmonary artery enlargement (Figure 1). Computed tomography of the chest revealed that both main bronchi were compressed by the pulmonary artery aneurysms, with no mural thrombus in the pulmonary arteries (Figure 2). The diameters of the right and left main pulmonary arteries were 69.8 and 55.5 mm, respectively. Bronchoscopy during mechanical ventilation confirmed nearly complete extrinsic compression of the left and right main stem bronchi without positive airway pressure (Figure 3 …