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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Renovascular hypertension resulting from renal artery stenosis is a potentially curable form of secondary hypertension. Although uncommon in the general hypertensive population, the prevalence of renovascular hypertension rises in selected groups of hypertensive patients. Because of the possibility of cure, screening measures for renal artery stenosis are warranted in hypertensive patients with clinical features suggestive of renovascular disease. For a long time, angiography has been considered the 'gold standard' in screening for arterial stenosis. However, it is invasive and associated with inherent morbidity. Thus, less invasive screening measures with high diagnostic sensitivity and specificity are currently being sought. Magnetic resonance angiography and captopril renal scintigraphy are safer alternatives to angiography, but are expensive and not widely available. Duplex ultrasound is more widely available and provides both anatomic and functional assessment of renal artery stenosis; however, sensitivity and specificity vary considerably among different laboratories. Echo-enhanced duplex ultrasound using the galactose-based agent Levovist(R) produces higher quality images of the renal artery than conventional color Doppler, while significantly reducing mean examination time and improving diagnostic confidence. In addition, Levovist does not compromise the safety of duplex ultrasound. Other advances in Doppler imaging techniques that may improve ultrasound sensitivity and specificity in detection of renal artery stenosis are power Doppler, echo-enhanced harmonic spectral Doppler imaging, and echo-enhanced harmonic power Doppler imaging.
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PMID:Diagnosis of renal artery stenosis and renovascular hypertension. 967 31

This study assessed whether Doppler-derived mitral and pulmonary venous flow parameters were predictors of pulmonary artery hypertension in patients with left ventricular dysfunction. Doppler echocardiographic examinations were performed in patients (n = 100) with dilated cardiomyopathy in sinus rhythm either symptomatic or asymptomatic before and after optimized therapy with ACE inhibitors, diuretics, and vasodilators. In case of weak or poor Doppler signals, measurable tricuspid regurgitation and pulmonary venous flow tracings were obtained after intravenous administration of 2.5 grams of Levovist at 400 mg/ml. At baseline, left ventricular ejection fraction was 30% +/- 7% and pulmonary artery systolic pressure was 48 +/- 14 mmHg. At the follow-up study carried out after 6 +/- 2 months, reversibility of pulmonary artery hypertension was apparent only in those patients exhibiting favorable changes of mitral flow curve from the restrictive or pseudonormal to impaired relaxation pattern (53 +/- 7 mmHg vs 38 +/- 8 mmHg; P < 0.0001). Numerous variables correlated significantly with pulmonary artery systolic pressure at baseline, while the correlations were generally weaker at the follow-up study. The closest correlations were found with E wave deceleration rate (r = 0.73) at baseline and with the systolic fraction of pulmonary venous flow forward peak velocities (r = -0.67) at follow-up. The stepwise regression model showed that the E wave deceleration rate and the degree of mitral regurgitation were the strongest independent predictors of pulmonary hypertension at baseline, while the ratio between pulmonary venous flow reverse and mitral wave velocities at atrial systole and ejection fraction added minor contributions, leading to a cumulative r value of 0.81. The systolic fraction was the strongest at the follow-up study, with minor contributions provided by the E wave deceleration rate and the left atrial dimension index, leading to a cumulative r value of 0.71.
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PMID:Doppler-derived mitral and pulmonary venous flow variables are predictors of pulmonary hypertension in dilated cardiomyopathy. 1235 40

The study was carried out in two different models of left ventricular hypertrophy: athlete's heart and essential arterial hypertension. Three groups of strictly age-matched males were studied: one group of 10 young adult untreated essential hypertensive patients (H), a second group of 10 athletes (A), and a group of 10 healthy individuals as controls (C). A Sonos 5500 echograph with S4 harmonic transducer was used with Levovist (ultrasonic tracer) before and after dipyridamole injection; digitised images of quantitative myocardial contrast echocardiography were collected with Power Harmonic Doppler. Angio images were analysed using dedicated PC software by placing a region-of-interest on the septum. Peak intensity, half-time (HT), the area under the curve of appearance and disappearance of microbubbles at 2/3 of PI, both in absolute and indexed values (/LVMi), were sampled. The per cent increase of PI after dipyridamole was significantly higher in C (+73%, P < 0.01) than in H (+31%) and in A (+33%) (P < 0.05). The area of appearance was significantly lower in H in comparison with C and A, both at rest and after vasodilatation. The disappearance area after dipyridamole was significantly higher in C and in A (+124%) than in H (+104%) (P < 0.05). Some hypothesis could be made: an impairment in the coronary microcirculatory function in hypertensive patients could be because of an in-crease in the arteriolar resistance. Angiogenesis and several different functional adaptations are the mechanisms that allow an optimal distribution of oxygen and of substrates to the hypertrophied myocardium of the athletes.
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PMID:Coronary microcirculation into different models of left ventricular hypertrophy-hypertensive and athlete's heart: a contrast echocardiographic study. 1269 70