Quantitative assessment of coronary stenosis by harmonic power Doppler with a simple pulsing sequence and vasodilator stress in patients

AbstractObjectivesWe examined whether myocardial contrast echocardiography (MCE) with harmonic power Doppler (HPD) employing a simple ultrasound pulsing sequence enables estimation of the severity of coronary artery stenosis in patients.BackgroundContrast intensity (CI) during MCE with intravenous microbubble infusion is dependent on the myocardial blood flow velocity (MBFV) and pulsing interval (PI).MethodsBased on an in vitro experiment, we devised the MBFV index calculated as the reciprocal of the magnitude of CI decay produced by abrupt PI shortening during intermittent imaging. In 68 coronary artery territories from 49 patients, myocardial HPD images were acquired during intravenous infusion of Levovist, while the long PI with 1:10 electrocardiographic gating was shortened to 1:1, both at baseline and during adenosine triphosphate infusion. The MBFV index in each coronary territory and MBFV reserve as the ratio between hyperemia and baseline were compared with the severity of corresponding coronary artery stenosis assessed by quantitative coronary angiography (QCA) or by pressure guide wire as the fractional flow reserve (FFR).ResultsBoth the MCE-derived MBFV index during hyperemia and MBFV reserve exhibited significant negative correlations with the QCA-derived stenosis severity (r = −0.56 and r = −0.64, respectively). The MBFV reserve positively correlated with FFR (r = 0.89). By combining the cutoff values of the MBFV index during hyperemia and MBFV reserve, ≥75% of stenoses defined by QCA were determined, with a sensitivity of 77.3%, specificity of 93.4%, and accuracy of 88.3%.ConclusionsShortening of PI during intravenous MCE with intermittent HPD imaging under vasodilator stress enables assessment of coronary artery stenoses in patients

Plasma brain natriuretic peptide as a surrogate marker for cardioembolic stroke

<p>Abstract</p> <p>Background</p> <p>Cardioembolic stroke generally results in more severe disability, since it typically has a larger ischemic area than the other types of ischemic stroke. However, it is difficult to differentiate cardioembolic stroke from non-cardioembolic stroke (atherothrombotic stroke and lacunar stroke). In this study, we evaluated the levels of plasma brain natriuretic peptide in acute ischemic stroke patients with cardioembolic stroke or non-cardioembolic stroke, and assessed the prediction factors of plasma brain natriuretic peptide and whether we could differentiate between stroke subtypes on the basis of plasma brain natriuretic peptide concentrations in addition to patient's clinical variables.</p> <p>Methods</p> <p>Our patient cohort consisted of 131 consecutive patients with acute cerebral infarction who were admitted to Kagawa University School of Medicine Hospital from January 1, 2005 to December 31, 2007. The mean age of patients (43 females, 88 males) was 69.6 ± 10.1 years. Sixty-two patients had cardioembolic stroke; the remaining 69 patients had non-cardioembolic stroke (including atherothrombotic stroke, lacunar stroke, or the other). Clinical variables and the plasma brain natriuretic peptide were evaluated in all patients.</p> <p>Results</p> <p>Plasma brain natriuretic peptide was linearly associated with atrial fibrillation, heart failure, chronic renal failure, and left atrial diameter, independently (F_4,126= 27.6, p < 0.0001; adjusted R²= 0.45). Furthermore, atrial fibrillation, mitral regurgitation, plasma brain natriuretic peptide (> 77 pg/ml), and left atrial diameter (> 36 mm) were statistically significant independent predictors of cardioembolic stroke in the multivariable setting (Χ²= 127.5, p < 0.001).</p> <p>Conclusion</p> <p>It was suggested that cardioembolic stroke was strongly predicted with atrial fibrillation and plasma brain natriuretic peptide. Plasma brain natriuretic peptide can be a surrogate marker for cardioembolic stroke.</p