Biomedical subjects

Alessandro Boccanelli

Publications and source records attributed to Alessandro Boccanelli.

6 recordsLinked to original sources

PubMed2003

Stenting of culprit lesions in unstable angina leads to a marked reduction in plaque burden: a major role of plaque embolization? A serial intravascular ultrasound study.

BACKGROUND: Intravascular ultrasound (IVUS) studies have shown that a mechanism of plaque compression/embolization contributes toward the poststenting increase in lumen area. The aim of this IVUS study was to compare the mechanisms of lumen enlargement after coronary stenting in 54 consecutive patients with unstable angina (UA) (group 1) and 56 with stable angina (group 2) to verify whether plaque embolization plays a major role in the former. METHODS AND RESULTS: Both groups underwent the IVUS assessment (speed, 0.5 mm/sec) before the intervention and after stent implantation. The lumen area, the external elastic membrane area, and the plaque+media area (PA) were measured at 0.5-mm intervals. PA reduction in the lesion site was significantly greater in group 1 (-2.50+/-1.97 versus -0.53+/-1.43 mm2, P<0.001). After stenting, 47% of the lumen area increase in group 1 was obtained by means of PA reduction, and 53% was attributable to external elastic membrane area increase; the corresponding figures in group 2 were 13% and 87% (P<0.05). Decrease in PA after stenting was the only significant predictor of the MB fraction of creatinine kinase (CK-MB) release in a multiple regression model (P=0.047). CONCLUSIONS: Serial volumetric IVUS assessment revealed in UA lesions a marked poststenting reduction in plaque volume, which is significantly greater than in stable angina and is associated with postprocedural CK-MB release. The decrease in PA during the procedure predicts CK-MB release in a multiple regression model. These findings suggest that stent deployment is often associated with plaque embolization in patients with UA.

Angina Pectoris↗

PubMed2003

Comparison of outcomes (early and six- month) of direct stenting with conventional stenting (a meta-analysis of ten randomized trials).

Although direct stenting (DS) is increasingly used in clinical practice instead of stent implantation after predilatation (conventional stenting [CS]), its impact has not been scientifically proved. We therefore performed, using Mantel-Haenszel analysis, a meta-analysis of the published randomized studies comparing DS with CS. Furthermore, all the key procedural data were systematically sought out and pooled. Ten trials (2,650 coronary lesions, 2,576 patients) were identified and entered into the analysis. Adopted angiographic exclusion criteria were homogeneous. DS, compared with CS, was found to have a similar success rate (98.7% vs 98.9%) and no specific complications. Across the studies, the mean rate of crossover to predilatation in the DS arm was 5.9%. Overall, DS was associated with a 17% procedural time (95% confidence interval [CI] 14% to 20%), a 18% fluoroscopic time (95% CI 15% to 21%), a 11% contrast volume (95% CI 9% to 14%), and a 22% cost reduction (95% CI 16% to 28%). In the early postintervention period, DS was associated with a trend toward reduction of each of the major adverse events (MACEs) and with a significant reduction of myocardial infarction (MI) + death (odds ratio [OR] 0.57, 95% CI 0.35 to 0.95). However, at 6 months, the OR (95% CI) for death, MI, target lesion revascularization, and MACEs were 0.47 (0.19 to 1.27), 0.72 (0.45 to 1.25), 1.07 (0.77 to 1.46), and 0.82 (0.63 to 1.08), respectively. In the subgroup of studies providing quantitative angiographic data, all the parameters were found to be similar between the CS and DS groups. In conclusion, the present meta-analysis shows that DS compared with CS, in selected coronary lesions, is safe, optimizes equipment use, and may enhance the early results of coronary interventions while warranting similar late clinical outcomes.

Blood Vessel Prosthesis Implantation↗

PubMed2002

Intravascular ultrasound and quantitative coronary angiography assessment of late in-stent restenosis: in vivo human correlation and methodological implications.

Quantitative coronary angiography (QCA) is routinely used for assessment of strategies aimed at reducing in-stent restenosis. Yet QCA enables only the measurement of luminal variation of stented segments and, unlike intravascular ultrasound (IVUS), provides only an indirect estimation of late in-stent neointimal formation, which has a key role in the process of in-stent restenosis. The aims of the present study were to correlate the IVUS measurement of in-stent intimal hyperplasia (IH) with QCA indexes of restenosis, to find out whether QCA is an adequate surrogate of IVUS, and, using either QCA and IVUS data, to define the sample sizes needed to demonstrate the effectiveness of strategies to reduce in-stent restenosis. The database of the European Imaging Laboratory was used to screen 154 stents implanted between 1997 and 2001 and studied by IVUS at 6 +/- 1 months of follow-up. All cases underwent serial QCA assessment (preintervention, postintervention, and follow-up). Only 131 cases with single stent implantation in native coronary arteries were included in the study. Stent restenosis, defined as percent diameter stenosis (DS) > 50%, was present at QCA in 69 out of 131 cases (53%). Linear regression analyses were performed to correlate the amount of IH, calculated by IVUS as the average of all cross-section areas (CSA; mean % IH CSA) and QCA indexes of restenosis (late loss and % DS). A positive significant correlation was found between IVUS mean % IH CSA and QCA % DS (r = 0.74; P < 0.0001) and between IVUS mean % IH CSA and QCA late loss (r = 0.72; P < 0.0001). Based on IVUS measurements of mean % IH CSA, a total sample size of 74 stents would be required in a two-arm comparison to have 0.80 power to detect at 0.05 significant level a 30% difference between two compared groups. Alternatively, adopting the QCA late loss, 230 stents would be required. QCA measurements of late in-stent restenosis are well correlated with IVUS calculation of in-stent neointimal formation. IVUS assessment of IH allows smaller sample sizes than QCA to document significant reductions of in-stent restenosis. Therefore, the use of IVUS should be encouraged in comparison studies aimed at revealing significant neointimal differences in small sample size populations.

Aged↗

PubMed2002

The extent of late in-stent neointima formation is modified by treatment with pravastatin: a preliminary study with intravascular ultrasound.

BACKGROUND: The aim of the present comparative, non-randomized intravascular ultrasound (IVUS) study was to test the effect of pravastatin on late neointima formation in stented de novo lesions. METHODS: The treatment group consisted of 28 consecutive patients in whom 31 stents were deployed; all patients were prescribed 40 mg daily of pravastatin for a mean follow-up period of 14 +/- 3 months (group 1). The control group consisted of 27 consecutive patients in whom 30 stents were deployed; lipid-lowering treatment was not prescribed; the mean follow-up period for this group of patients was 13 +/- 3 months (group 2). At follow-up IVUS images were acquired at a continuous 0.5 mm/s speed. IVUS measurements of the lumen area, stent area and neointima area were calculated within the stent at 0.5 mm intervals. RESULTS: The stent dimensions and technique of implantation were similar in the two groups. At follow-up the minimal lumen diameter at quantitative coronary angiography was slightly larger in group 1 than in group 2 (2.43 +/- 0.58 vs 2.17 +/- 0.59 mm, p = NS), while the late loss tended to be lower in group 1 than in group 2 (0.28 +/- 0.39 vs 0.63 +/- 0.37 mm, p = NS). At IVUS evaluation, the lumen and stent areas were similar in the two groups whereas the percent neointima area was significantly lower in group 1 than in group 2 (21 +/- 11 vs 29 +/- 11% respectively, p < 0.03). CONCLUSIONS: Pravastatin treatment was associated with a significantly reduced late in-stent neointima formation as assessed at IVUS.

Aged↗

PubMed2002

[Refractory heart failure. Multisite stimulation].

The pathophysiological background of cardiac resynchronization therapy is represented by the intraventricular conduction delay such as left bundle branch block, present in about one third of patients with dilated cardiomyopathy. Intraventricular conduction block, with or without atrioventricular delay, adversely influences ventricular function due to unsynchronized contraction and is associated with a poor prognosis. Contractile dyssynchrony and abnormal atrioventricular delay can be corrected by non-conventional stimulation modalities such as left ventricular pacing or biventricular pacing associated with preexcitation to restore the physiological atrioventricular timing. Over the last decade several studies have reported the short- or long-term favorable effects of resynchronization therapy on the left ventricular function and remodeling, the quality of life, the functional capacity, the adrenergic activity, and the reduced rehospitalization rate. The most significant results have been reported in patients with a QRS duration > or = 150 ms, while the InSync Italian Registry has shown improvement even in patients with a QRS duration < 150 ms as well as in patients with atrial fibrillation. On the basis of such data it may be argued that the activation sequence of the different walls of the left ventricle is likely more important than the QRS duration. Inclusion criteria commonly used in the published or ongoing trials are: moderate to severe congestive heart failure (NYHA functional class III-IV) on optimized pharmacological treatment; left ventricular ejection fraction < or = 35%; left ventricular diastolic diameter > 60 mm; end-diastolic mitral regurgitation; no need of conventional pacing. While with regard to the surrogate endpoints the results of published trials are very encouraging, we do not yet know whether resynchronization therapy prolongs the life expectancy of patients with heart failure. Studies able to provide important answers to these problems are near completion. In the meanwhile, in agreement with the guidelines of the European Society of Cardiology, it seems prudent to employ such a therapy only in case of patients satisfying the above-mentioned criteria.

Heart Failure↗

PubMed2002

Normal distribution of an intravascular ultrasound index of vessel remodeling.

BACKGROUND: As a consequence of plaque accumulation, coronary arteries may undergo both compensatory enlargement and paradoxical constriction. The aim of this study was to address the distribution of the different remodeling patterns in patients with obstructive coronary atherosclerosis. METHODS: Eighty-seven non-branching segments of native coronary arteries with de novo, focal, non-ostial lesions were imaged at intravascular ultrasound (IVUS). Images were acquired with a motorized pull-back at a speed of 0.5 mm/s. The cross-sectional area (CSA) circumscribed by the external elastic membrane (EEM), the plaque + media complex and the lumen area were measured at its narrowest site (CSA with the minimal lumen area) and in the reference segment (average of proximal and distal reference cross-sections, defined as the most normal looking sites). The IVUS index of vessel remodeling (VRI) was calculated using the following formula: (narrowest site EEM CSA--reference EEM CSA)/reference EEM CSA*100. The index was tested for normality using the Kolmogorov-Smirnov goodness-of-fit test. RESULTS: The frequency distribution of VRI was found to have a normal unimodal distribution (p = 0.60). VRI ranged from -60 to +164, with a mean of 9.3 +/- 28.0 and a median of 3.6. Frequency distribution of VRI slightly skewed towards right (skewness index 1.69). None of the analyzed clinical and morphological variables predicted the presence of compensatory enlargement as opposed to paradoxical constriction. CONCLUSIONS: The frequency distribution of the vascular remodeling of de novo coronary lesions is unimodal. Therefore, compensatory enlargement and paradoxical constriction represent the extremes of a continuous spectrum.

Coronary Artery Disease↗