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Luigi De Simone

Publications and source records attributed to Luigi De Simone.

8 recordsLinked to original sources
PubMed2005

Transthoracic Doppler echocardiography of mammary artery grafts to assess graft function.

BACKGROUND: Transthoracic Doppler echocardiography of internal mammary artery grafts (MAGs) has been tested by the supraclavicular approach, but little information is available about the parasternal approach. OBJECTIVE: To evaluate the usefulness of parasternal transthoracic Doppler echocardiography to assess the patency of left and right MAGs. PATIENTS AND METHODS: Forty-eight patients with previous MAGs were divided into two groups on the basis of coronary angiography: 42 patients had patent MAGs and six patients had severe MAG stenosis. Doppler echocardiography of MAGs was performed on all patients, both at baseline and after low-dose dipyridamole infusion. Systolic and diastolic time-velocity integrals and their ratios were obtained, and MAG flow reserve was calculated. RESULTS: Patients with patent MAGs had a predominant diastolic flow, while a prominent systolic pattern was found in the presence of MAG stenosis. In patients with stenosis, baseline Doppler analysis showed a lower diastolic peak velocity (DPV) (P<0.01), diastolic time-velocity integral (P<0.05), and diastolic and systolic time-velocity integral ratios (both P<0.005), and a reduced MAG flow reserve (P<0.001). In the overall population, when adjusting for clinical variables, a multilinear regression analyis underscored MAG flow reserve (beta=0.38, P<0.01) and baseline DPV (beta=0.29, P<0.05) as independent determinants of MAG stenosis (cumulative R2=0.25, P<0.005). CONCLUSIONS: Doppler echocardiographic evaluation of MAGs is a reliable, noninvasive tool to assess MAG patency and functional status of the vessel. MAG blood flow reserve and baseline DPV are independent determinants of MAG stenosis.

Aged↗
PubMed2003

Coronary flow reserve in hypertensive patients with appropriate or inappropriate left ventricular mass.

OBJECTIVE: To assess the association between coronary flow reserve (CFR) and levels of left ventricular mass (LVM) exceeding the compensatory needs in arterial hypertension. DESIGN, SETTINGS AND PATIENTS: The association between the excess of LV mass and CFR was assessed in a population of 40 consecutive hypertensive outpatients free of coronary heart disease, 22 with appropriate and 17 with inappropriately high LVM (i.e. LVM exceeding 128% of the value predicted by sex, stroke work and height in m(2.7)). The CFR (the ratio between dipyridamole and basal diastolic peak velocity) of the distal left anterior descending artery was measured by transthoracic Doppler echocardiography. RESULTS: Patients with inappropriate LVM had similar age, body mass index (BMI), baseline blood pressure (BP) and coronary velocities, but lower LV systolic function, post-dipyridamole diastolic peak velocities (P < 0.05) and lower CFR (P < 0.002) than patients with appropriate LVM. CFR was negatively related to the extent of the excess of LVM (beta = -0.44, P < 0.005), independently of potential combined effect of age, BMI and post-dipyridamole diastolic BP. Impairment of CFR (i.e. < 2) was better discriminated by identification of clear-cut inappropriate LVM (P < 0.004) than by the presence of LV hypertrophy (i.e. LV mass index > or = 51 g/m(2.7); P = 0.057). CONCLUSIONS: In hypertensive patients free of coronary artery disease, the degree of reduction in CFR is associated with the excess of LVM beyond the values compensatory for individual haemodynamic load. This relation is also independent of the presence of LV hypertrophy.

Adaptation, Physiological↗
PubMed2003

Noninvasive assessment of left and right internal mammary artery graft patency using transthoracic color Doppler echocardiography.

BACKGROUND: The aim of this study was to evaluate the patency of left and right internal mammary artery grafts respectively on the left anterior descending and right coronary artery by noninvasive transthoracic color Doppler echocardiography. METHODS: Thirty eight patients (34 males, 4 females, mean age 59 +/- 2 years), with a history of coronary artery bypass grafting for a total of 42 mammary artery grafts, were studied by means of color Doppler echocardiography at baseline and after vasodilation with dipyridamole infusion (0.56 mg/kg i.v. over 4 min). The evaluated echocardiographic parameters included: systolic (SPV) and diastolic peak velocities (DPV), systolic (SVI) and diastolic velocity-time integrals (DVI), and the DPV/SPV and DVI/SVI ratios. We also calculated the dipyridamole infusion to baseline ratio of the diastolic peak velocities (DPVdip/DPVbaseline), the index of internal mammary artery graft blood flow reserve and the percent DPV increment as an index of graft stenosis. RESULTS: On the basis of coronary angiography, two groups were selected: group A (36 mammary grafts) with patent grafts and group B (6 mammary grafts) with moderate or severe stenosis of the grafts. Group A had a predominant diastolic pattern with a DPV of 0.24 +/- 0.13 m/s, whereas group B had a predominant systolic pattern with a reduced DPV of 0.12 +/- 0.03 m/s (p < 0.01). Dipyridamole induced an increase in the DPV respectively of 86.8 +/- 64.4% in group A and 13.8 +/- 15.9% in group B (p < 0.001). Statistical analysis (Mann-Whitney test) revealed a significant difference between the two groups for the baseline DPV (p < 0.01), DVI (p < 0.05), DPV/SPV ratio (p < 0.005), DVI/SVI ratio (p < 0.05), and for the after dipyridamole infusion values: DPV (p < 0.0001), DVI (p < 0.005), DPV/SPV ratio (p < 0.001), and DVI/SVI ratio (p < 0.05). Multivariate analysis showed that the percent DPV increment, the DPVdip/DPVbaseline ratio and the baseline DPV were independent determinants of the stenosis as evaluated at angiography (beta = -0.38, p < 0.01; beta = -0.37, p < 0.01, and beta = -0.33, p < 0.05, respectively; cumulative r2 = 0.25, standard error 0.30 m/s, p < 0.005). CONCLUSIONS: The echocardiographic evaluation of the mammary grafts is a simple, noninvasive method for the assessment of the graft patency and of the functional status of the vessel. The percent DPV increment and baseline DPV were independent determinants of mammary graft stenosis.

Blood Flow Velocity↗
PubMed2002

Coronary flow reserve and myocardial diastolic dysfunction in arterial hypertension.

The aim of this study was to assess the relation between coronary blood flow and left ventricular (LV) myocardial diastolic dysfunction in arterial hypertension. The study population included 30 hypertensive patients who were free of coronary artery disease and pharmacologic therapies. They underwent standard Doppler echocardiography and color tissue Doppler of the middle posterior septum at baseline and with high-dose dobutamine, and second-harmonic Doppler flow analysis of the distal left anterior descending coronary artery at baseline and after vasodilation by dipyridamole (0.56 mg/kg IV in 4'). Coronary flow reserve (CFR) was estimated as the ratio of hyperemic and baseline diastolic flow velocities. According to CFR, hypertensives were divided into 2 groups: 15 patients with normal CFR (>/=2) and 15 patients with reduced CFR (<2). The 2 groups were comparable for sex, age, body mass index, baseline heart rate, and blood pressure. LV mass index was greater in hypertensives with reduced CFR (p <0.01). By color tissue Doppler, baseline and high-dose dobutamine septal systolic velocities did not differ between the 2 groups. The ratio between myocardial velocities in early diastole and at atrial contraction (E(m)/A(m) ratio) was lower in patients with reduced CFR, both at baseline (p <0.05) and with high-dose dobutamine (p <0.00001). After adjusting for age, body mass index, LV mass index, and both high-dose dobutamine diastolic blood rate and heart rate by a multiple linear regression analysis, E(m)/A(m) ratio at high-dose dobutamine was independently associated with CFR in the overall population (beta 0.62, p <0.0005) (cumulative R(2) 0.38, p <0.0005). In conclusion, this study provides evidence of an independent association between CFR and myocardial diastolic function. In hypertensive patients without coronary artery stenosis, CFR alteration may be a determinant of myocardial diastolic dysfunction or diastolic impairment that should be taken into account as possibly contributing to coronary flow reduction.

Adult↗
PubMed2002

Is the time course of clozapine response correlated to the time course of clozapine plasma levels? A one-year prospective study in drug-resistant patients with schizophrenia.

The relationship between the time course of clinical response to clozapine and the time course of clozapine plasma levels has never been investigated. In the present study, we assessed prospectively the clinical response to clozapine and the plasma levels of the drug and its major metabolites in 32 drug-resistant patients with schizophrenia kept on a fixed dose of 600 mg/day for 1 year Four of the patients met response criteria at week 4 of treatment. At weeks 8, 12, and 24, new responders were 7, 6, and 6, respectively. Nine patients never achieved clinical response. In responders at week 4, clozapine and clozapine-N-oxide plasma levels were significantly higher than in both new responders at weeks 8, 12, and 24 and nonresponders. In new responders at weeks 8, 12, and 24, in spite of a fixed clozapine daily dose, mean drug plasma levels progressively rose up to when clinical response occurred; then, the levels remained stable over time. Nonresponders exhibited mean clozapine plasma levels constantly below the value of 260 ng/ml, with N-demethylation as the preferred metabolic route. The present findings show, for the first time, that the time course of the clinical response to clozapine may be linked to the time course of plasma levels of clozapine and its major metabolites.

Adult↗
PubMed2002

Positive association between circulating free insulin-like growth factor-1 levels and coronary flow reserve in arterial systemic hypertension.

BACKGROUND: The reduction of coronary flow reserve (CFR) found in arterial hypertension may be due to changes in afterload, left ventricular (LV) structure, and metabolic factors. Also, insulin-like growth factor-1 (IGF-1) may be associated with the magnitude of CFR in relation to its modulating action on cardiac and endothelial function. METHODS: A total of 44 newly diagnosed, untreated hypertensive patients, who were free of diabetes mellitus and coronary artery disease, underwent M-mode analysis, second-harmonic Doppler echocardiographic assessment of CFR (dipyridamole infusion 0.56 mg/kg intravenously in four patients), determination of circulating free IGF-1, and insulin resistance. Based on CFR levels, hypertensive subjects were divided into two groups: 18 with normal CFR (> or = 2) and 26 with impaired CFR (<2). RESULTS: Patients with normal CFR had lower diastolic blood pressure, heart rate, and LV mass index but higher free circulating IGF-I than patients with reduced CFR (P < .001). Insulin resistance was not significantly different between the two groups. In a first multilinear regression analysis that included demographic and echocardiographic variables, insulin resistance was independently associated with CFR (standardized beta coefficient = -0.31, P < .05) in the overall population. However, in a subsequent model which included also IGF-1, the relationship between insulin resistance and CFR disappeared, whereas IGF-1 was the main independent determinant of CFR (beta = 0.51, P < .0002). CONCLUSIONS: Free IGF-1 circulating levels are independently associated with CFR in hypertensive individuals free of overt coronary artery disease. A possible beneficial effect exerted by IGF-1 on coronary blood flow may be supposed in arterial hypertension.

Adult↗
PubMed2002

[Mitral stenosis: echocardiographic evaluation].

The diagnostic tools available for the evaluation of mitral stenosis are two-dimensional and Doppler echocardiography, which are able to identify morphologic and flow changes. Two-dimensional echocardiography can be used to assess the morphological appearance of the mitral valve apparatus, including its mobility and thickness and the presence of calcified leaflets and subvalvular fusion. Wilkins'score permits evaluation of each variable which, on the basis of its severity, is scored according to a point system ranging from 1 to 4. In patients with severe mitral stenosis, a low total score (< 8) and elastic symmetric commissures suggest valvuloplasty. A total score > 10 and the presence of more than mild mitral regurgitation or of calcification of both commissures suggest valvular replacement. The left atrial and ventricular chamber sizes and other associated valvular diseases can also be assessed at two-dimensional or Doppler echocardiography. The severity of obstruction can be assessed using two-dimensional and Doppler echocardiographic area (pressure half-time, proximal isovelocity surface area, continuity equation) and with the mean transmitral gradient measured using a continuous wave Doppler signal across the mitral valve. Valvuloplasty can also be performed in patients with a high score when surgery is contraindicated. During follow-up it is necessary to evaluate the area, the mean gradient, the right ventricular systolic pressure and the presence of a residual atrial septal defect and mitral regurgitation. Restenosis is diagnosed when the valve area decreases to 50% of that achieved during valvuloplasty or surgery.

Adult↗