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F Prati

Publications and source records attributed to F Prati.

At least 37 records · Page 2Linked to original sources
PubMed1998

Extent and distribution of atherosclerotic plaque in relation to major coronary side-branches: an intravascular ultrasound study in vivo.

BACKGROUND: The non-uniform extent and distribution of atherosclerotic plaque at bifurcations have been described by necropsy studies and they are related to local blood-flow disturbances. Systematic evaluation of plaque extent and distribution upstream and downstream of major coronary side-branches has not yet been evaluated in vivo. METHODS: We used intravascular ultrasound imaging in 41 patients with atherosclerotic disease to study the region of 73 major coronary side-branches at 2 mm increments proximal and distal to the side-branch (657 images: 73 at origin of side-branch; 292 proximal; 292 distal). The maximum (MXT) and minimum (MINT) plaque thickness and the plaque burden percentage (% PB) were measured in all the segments. The angle of distribution of maximum plaque thickness with respect to the origin of the side-branch was determined in each cross-section and assigned to S1 when located on the semicircle in the direction of the origin of the side-branch and to S2 when located on the opposite wall. RESULTS: The mean value of maximum plaque thickness and the plaque burden percentage were similar at the origin and in the two adjacent segments proximal and distal to the side-branch (1.0 +/- 0.48 mm, 1.06 +/- 0.48 mm and 0.98 +/- 0.48 mm; 45 +/- 19%, 46 +/- 19% and 44 +/- 18%). In distal sites of analysis, the plaque was more frequently eccentric in comparison to proximal sites (presence of an arc of plaque-free wall: 79% versus 62% in very distal and in very proximal sites respectively; p < 0.05). The prevalence of maximum plaque in S2 was higher at the origin (84%) and in adjacent distal segments (86%) as compared with the adjacent proximal segments (60%; p < 0.0001). CONCLUSIONS: The distribution of plaque is influenced by the origin of a major coronary side-branch in patients with coronary atherosclerosis: in distal sites the location of maximum plaque is almost always eccentrically distributed on the wall opposite the take-off.

Adult↗
PubMed1998

Incidence of compensatory enlargement and paradoxical shrinkage of coronary arteries in presence of atherosclerotic lesions: an intracoronary ultrasound study based on multiple cross-section analysis per artery.

BACKGROUND: The aim of the study was to evaluate with intravascular ultrasound (IVUS) the incidence of compensatory enlargement and paradoxical shrinkage in 50 de novo coronary lesions, using two different approaches: 1) a single cross-section analysis and 2) a multiple cross-section analysis per artery. A 3-D IVUS system based on contour detection of lumen and plaque was applied (image acquisition speed: 0.5 mm/s, digitization rate: 5 images/s). In each cross section, we determined: 1) the lumen area (LA), 2) the external elastic membrane area (EEMA), 3) the plaque+media complex (p+m), 4) the relative EEMA = cross section EEMA/reference EEMA, 5) the relative p+m area = cross-section p+m area/reference p+m area, 6) the lumen area stenosis: 1-(cross-section LA/reference LA). In the single cross-section analysis, compensatory vessel enlargement was defined as narrowest EEMA > reference EEMA, and paradoxical vessel constriction as narrowest EEMA < reference EEMA. In the multiple cross-section analysis, compensatory vessel enlargement was defined as the presence of a significant positive correlation between relative EEMA and relative p+m area and paradoxical vessel constriction as a significant negative correlation between relative EEMA and lumen area stenosis. RESULTS: In the single cross-section analysis, compensatory vessel enlargement and paradoxical constriction occurred in 58 and 42% of cases respectively. The multiple cross-section per artery analysis showed compensatory vessel enlargement in 80% of cases and paradoxical constriction in 36% of cases and revealed the combination of compensatory enlargement with paradoxical constriction in 22% of the analyzed segments. CONCLUSIONS: Compensatory enlargement of coronary arteries was underestimated by the single cross-section analysis and was observed in 80% of cases when a multiple cross-section per artery analysis was applied. Paradoxical shrinkage was less common and often occurred in combination with compensatory enlargement within the same analyzed segment.

Adult↗
PubMed1998

[The clinical, angiographic and procedural predictors of thrombosis and restenosis in Micro stent II (AVE) coronary stents].

The aim of the study was to assess the incidence and the predictors of thrombosis and restenosis in Micro stent II AVE. In a sample of 197 stents successfully implanted in 181 consecutive patients, the incidence of thrombosis was 4.1%. The multivariate analysis showed the minimum lumen diameter post-stenting to be the only independent predictor of overall thrombosis. In fact, we found that the risk of thrombosis increases as the minimal lumen diameter decreases. Angiographic follow-up was available in 74% of the stents at 6.8 +/- 4.1 months and stent restenosis occurred in 26.2% of cases. Independent predictors of restenosis (multivariate linear discriminant analysis) were: 1) nominal stent diameter (the risk of restenosis decreases as the stent diameter increases); 2) the ratio between the diameter of the balloon carrying the stent measured at the maximum pressure/nominal stent diameter (the risk increases as the ratio decreases); 3) stented vessel (the risk increases in the following order: right coronary < circumflex < left anterior descending); 4) the American Heart Association classification of lesion morphology (the risk increases in the order A < B < C); 5) a lower risk was found in the absence of diabetes mellitus.

Aged↗
PubMed1997

On-line three-dimensional intracoronary ultrasound for guidance of catheter based interventions.

Intracoronary ultrasound (ICUS) provides valuable information on the distribution and composition of atherosclerotic plaque. For this reason its use for guidance of interventional procedures has been advocated. Recently, on-line systems of three-dimensional reconstruction have been introduced and offer great potential for guidance of interventional procedures since valuable details on longitudinal architecture of the plaque under treatment are obtained. In this article we review the current clinical application of three-dimensional (3-D) ICUS and report our experience with the use of an on-line 3-D ICUS system for guidance of interventional procedures. In our experience 3-D reconstruction of ICUS proved to be a feasible method facilitating device selection and guidance of catheter based interventions.

Catheter Ablation↗
PubMed1997

Is quantitative angiography sufficient to guide stent implantation? A comparison with three-dimensional reconstruction of intracoronary ultrasound images.

Intracoronary ultrasound (ICUS) frequently reveals stent underexpansion despite a satisfactory angiographic result by visual assessment. Whether on-line quantitative coronary angiography (QCA) alone can guide optimal stent deployment is still unknown. The aim of the study was to assess the usefulness of quantitative coronary angiography in the evaluation of optimal stent expansion, confirmed with a new on-line system of 3-D reconstruction of ICUS. The results obtained with 3-D ICUS were compared with the measurements achieved with QCA analyses in 49 patients (70 stents: 31 Palmaz-Schatz, 22 Wallstent, 7 Cordis, 6 Micro-stent, 2 Gianturco-Roubin, 2 Multi-Link). Following delivery of the stent, high pressure intrastent balloon inflation (14.2 +/- 3.3 atmospheres) was performed in all 70 stents. Optimal stent implantation by QCA was defined as minimal lumen diameter post-stenting > or = 90% of the reference diameter preintervention. Percent diameter stenosis (% DS) post-stenting was defined as minimal lumen diameter divided by the reference diameter post-stenting. The on-line 3-D ICUS reconstructions and measurements were performed processing the images on-line in the catheterization laboratory with an automated contour detection algorithm based on acoustic quantification. ICUS criteria for optimal stent expansion were defined as: 1) complete apposition of stent struts to vessel wall; 2) minimal stent lumen cross-sectional area > or = 80% of the average lumen area of the proximal and distal reference segments; 3) symmetry index (minimum divided by maximum lumen diameter) > 0.7. Ninety-seven percent of the deployed stents met the QCA criteria. Whilst 3-D ICUS documented complete stent apposition to the vessel wall in all cases and a symmetric expansion in 65 of 70 lesions (93%), the stent minimal lumen area was > or = 80% only in 30 out of 70 stents (43%). The diagnostic sensitivity and specificity at 10% residual diameter stenosis provided by QCA for optimal stent expansion compared to 3-D ICUS criteria were 86 and 45%, respectively. In conclusion 3-D ICUS criteria of adequate stent expansion were achieved only in 43% of patients despite the application of aggressive strategies of stent deployment leading to optimal results with quantitative angiography. Ten percent residual diameter stenosis provided by QCA may be an acceptable alternative for optimal stent deployment in clinical practice. The clinical benefit of an ICUS guided approach of stent deployment and of a lower cost strategy using on-line QCA guidance should be compared in large prospective randomized studies.

Angiocardiography↗
PubMed1996

Usefulness of three-dimensional reconstruction for interpretation and quantitative analysis of intracoronary ultrasound during stent deployment.

We examined 49 coronary stents in 33 patients after angiographically guided optimization of the deployment by intracoronary ultrasound, and compared the findings of a conventional 2-dimensional analysis approach with the results obtained from an automatic lumen recognition provided by a 3-dimensional reconstruction system. The automatic lumen analysis demonstrated that only 15 stents (31%) fulfilled defined ultrasound criteria of adequate stent deployment, and that 5 of these cases were missed by the conventional approach, which systematically overestimated the dimensions of the minimal stent lumen.

Angioplasty, Balloon, Coronary↗
PubMed1996

Usefulness of on-line three-dimensional reconstruction of intracoronary ultrasound for guidance of stent deployment.

The additional information provided by automated on-line 3-dimensional (3-D) reconstruction of intracoronary ultrasound (ICUS) was assessed in 42 patients (62 stents) who underwent stent deployment after achieving an optimal quantitative angiographic result. In 10 of 42 patients, 3-D ICUS was also performed before stenting. ICUS images of stents and adjacent reference segments were acquired by using a motorized pullback at a constant speed (1 mm/s) and immediately processed in the catheterization laboratory. Optimal stent expansion was detected by 3-D ICUS in case of complete apposition of stent struts to the vessel wall. Furthermore, an attempt was made to maximize the intrastent lumen area to match lumen area of the reference segment and to cover with stents all the segments with residual significant lesions (plaque burden >50%). Three-dimensional automated reconstruction of ICUS was successful in 8 of 10 patients (80%) before, and in 36 of 42 patients (86%) after stent deployment. In all 8 patients who underwent successful 3-D ICUS assessment before stent implantation, the selection of stent length was facilitated by accurately measuring the lesion length. After stenting, 3-D ICUS modified the management strategy in 21 of 36 patients (58%), triggering additional high-pressure dilatations in 13 patients (36%) and additional stent deployment in 8 (22%). In conclusion, on-line 3-D ICUS facilitates stent selection and strongly modifies the revascularization strategy by accurately detecting stent underexpansion and presence of uncovered lesions.

Aged↗
PubMed1996

Optimized expansion of the Wallstent compared with the Palmaz-Schatz stent: on-line observations with two- and three-dimensional intracoronary ultrasound after angiographic guidance.

Optimized stent expansion by high-pressure inflations of oversized balloons has initially been derived from experience obtained with the Palmaz-Schatz stent, whereas there is little experience with this strategy in the Wallstent. By using this approach with quantitative coronary angiographic guidance, 20 Wallstents and 20 Palmaz-Schatz stents were implanted in 34 patients and consecutively examined by conventional two-dimensional (2D) intracoronary ultrasound (ICUS) and three-dimensional (3D) ICUS on the basis of the application of a pattern recognition algorithm. Ultrasound criteria of adequate stent expansion were defined as a complete apposition of the stent to the vessel wall, a stent symmetry index (SSI = minimum/maximum lumen diameter) > or = O.7, and a stent-reference lumen area ratio (SRR = Minimum intrastent lumen area/Average of proximal and distal reference lumen area) > or = O.8. In all cases a smooth angiographic lumen and a negative diameter stenosis, on the basis of a distal reference, was achieved. For the Wallstents ICUS showed a higher SSI (2D, 0.95 +/- 0.04 vs 0.85 +/- 0.09; p < 0.001; 3D, 0.90 +/- 0.09 vs 0.82 +/- 0.11, p < 0.05) and a lower SRR (2D, 0.66 +/- 0.12 vs 0.81 +/- 0.13, p < 0.005; 3D, 0.63 +/- 0.14 vs 0.74 +/- 0.15, p < 0.05) than for the Palmaz-Schatz stents. Ninety percent of failure in meeting these criteria resulted from a low SRR. The incidence of incomplete stent apposition (one in both stents) or SSI <0.7 was low and generally associated with an SRR <0.8. The Wallstents met the ICUS criteria less often (2D, 2(1O%) vs 10(50%), p < 0.01; 3D, 3(15%) vs 9(45%), p < 0.05), were significantly longer (35.1 +/- 7.7 mm and 14.3 +/- 3.3 mm, p < 0.0001), and generally demonstrated a larger vessel tapering, measured as proximal minus distal ICUS reference lumen area (1.33 +/- 2.91 mm2 vs 0.44 +/- 1.97 mm(2), not significant). Wallstents meeting the ICUS criteria, however, showed less vessel tapering (0.18 +/- 1.64 mm(2)). Thus optimized stent expansion was followed by excellent angiographic results for both Palmaz-Schatz and Wallstent. Although angiographic results and visual assessment of the ICUS examination suggested a good outcome, few Wallstents met the ICUS criteria in contrast to the Palmaz-Schatz stents. The low value of the SRR in the Wallstents is likely to be caused by vessel tapering, suggesting that this criterion may be unsuitable in assessing the adequacy of the expansion of relatively long stents such as the Wallstent.

Aged↗
PubMed1996

Three-dimensional intracoronary ultrasound imaging. Methodology and clinical relevance for the assessment of coronary arteries and bypass grafts.

Three-dimensional (3-D) reconstruction of intracoronary ultrasound (ICUS) images has an increasing application as the applicability of systems of on-line analysis provides a superior guidance by coupling the advantages of a high-resolution cross-sectional imaging with an overview of stenosis and reference segments. Detection of the external contour of the vessel which is a prerequisite for measurements of coronary plaques is currently not provided by the algorithms for automated on-line analysis. Thus, off-line reconstruction is required for studies aiming at the assessment of progression/regression of atherosclerosis and of mechanisms of interventions or restenosis. Various 3-D reconstruction methods with specific advantages and limitations are able to meet the different requirements concerning applicability, quality of visualization, and accuracy of quantification. The use of 3-D ICUS in the assessment of cardiac transplant recipients permits a more reliable and accurate quantification of intimal hyperplasia as seen in cardiac allograft arteriopathy. In patients undergoing bypass surgery it may influence the therapeutic decision, since it allows to determine the longitudinal extent of calcification and frequently discovers atherosclerosis in angiographically normal segments. Vessel stenoses both of native coronary arteries and bypass grafts can be studied by 3-D ICUS and additional information can be obtained during catheter based interventions. Despite some remaining technical limitation 3-D reconstruction of ICUS images has the potential of becoming a practical tool to simplify the interpretation and quantification of ICUS images.

Algorithms↗
PubMed1995

Cardiac disease after chest irradiation for Hodgkin's disease: incidence in 108 patients with long follow-up.

Occult or overt but delayed cardiac disease after thoracic radiotherapy for Hodgkin's disease may be common. Detailed cardiac evaluation was performed in 108 patients, mean age 46 +/- 6.2 years, with Hodgkin's disease at 175 +/- 43 months after irradiation. The study protocol included clinical examination, graded treadmill exercise test and echocardiography. Some patients with angina pectoris, previous myocardial infarction and an abnormal ECG were studied by thallium-201 scintigraphy, cardiac catheterization and coronary angiography. Cardiac disease was found in 12 patients (11%). Three patients had angina pectoris, one patient had myocardial infarction, two complained of dyspnea on effort and two had congestive heart failure. At catheterization, constrictive pericarditis was diagnosed in four patients; in two additional patients an occult constrictive pericarditis was found. One patient had both mitral and tricuspidal regurgitation and one had mitral regurgitation alone. Eight patients (7.4%) had severe coronary artery disease; four of these had associated constrictive pericarditis. Four patients had a pericardiectomy and another four had undergone coronary artery by-pass graft. Two patients died after operation from persistent pericardial constriction. It is concluded that the incidence of delayed cardiac disease after radiotherapy is relatively high; chronic pericardial disorders and coronary artery disease are the most frequent manifestations of this disease. Standard surgical treatment may be beneficial because of the relative youth of these patients.

Adult↗
PubMed1995

Mechanism of high-speed rotational atherectomy and adjunctive balloon angioplasty revisited by quantitative coronary angiography: edge detection versus videodensitometry.

High-speed rotational coronary atherectomy (RA) is primarily used to treat complex lesions. Quantitative angiographic analysis of such complex lesions by edge detection is often unsuitable, whereas videodensitometry, measuring vessel dimensions independently of the target stenosis contours, may offer potential advantages. To gain insight into the operative mechanism of RA and to study the agreement between the two quantitative angiographic methods in measuring the minimal luminal cross-sectional area, the edge detection and videodensitometry techniques were applied to coronary angiograms of 21 lesions in 19 patients with symptoms who underwent successful RA and balloon angioplasty (BA). Obstruction diameter as determined by edge detection increased from 1.00 +/- 0.31 mm before intervention to 1.35 +/- 0.29 mm after RA (p < 0.001) and further increased to 1.74 +/- 0.33 mm after adjunctive BA (p > 0.001). The mean between-method difference (edge detection minus videodensitometry) was 0.34 mm2 before intervention, 0.13 mm2 after RA, and 0.09 mm2 after adjunctive BA (not significant). The standard deviation of the differences decreased from +/- 0.87 mm2 before intervention to +/- 0.80 mm2 after RA (not significant) and increased after BA significantly to +/- 1.21 mm2 (p < 0.05). Thus edge detection and videodensitometry provided equivalent immediate angiographic results after RA and adjunctive BA. The good agreement after RA may reflect the operative mechanism of RA, which by ablation of noncompliant plaque material yields a circular symmetric lumen with smooth surface. The increased dispersion of the between-method differences observed after adjunctive BA presumably results from dissections, plaque ruptures, and loss of luminal smoothness after balloon dilatation.

Absorptiometry, Photon↗
PubMed1995

Transient myocardial ischemia detected by Holter monitoring during the early post-infarction period.

BACKGROUND: On the basis of extensive studies concerning the prognostic value of Holter monitoring in patients with angina, we evaluated the clinical outcome of patients with transient ischemic episodes soon after myocardial infarction. METHODS: The incidence and clinical significance of myocardial ischemia, detected in the acute phase of myocardial infarction, were evaluated in 87 patients. Twenty-four-hour Holter recordings were obtained on the 2nd, 4th, 6th, and 12th hospital day. RESULTS: Myocardial ischemia was detected during at least one of the four recording periods in 28 patients (32%). A total of 157 ischemic episodes were documented. The proportion of recordings that showed transient myocardial ischemia progressively declined from 20% on the 2nd day to 5% on the 12th post-infarction day. Of the 157 ischemic episodes, 132 (84%) were silent and 25 (16%) were symptomatic. Transient ST-segment elevation was present in 99 of the 157 episodes (63%), while transient ST-segment depression occurred in the remaining 58 of the 157 cases (37%). One or more in-hospital cardiac events (reinfarction, acute pulmonary edema, ventricular tachycardia or fibrillation, cardiac death) were more frequent in patients with (group I) than in those without (group II) transient myocardial ischemia [nine out of 28 (32%) versus six out of 59 (10%); P < 0.03]. At follow-up (mean 11.5 +/- 2 months) the incidence of cardiac events (angina, reinfarction, heart failure, ventricular tachycardia or fibrillation, revascularization procedures, cardiac death, sudden death) was comparable in the two groups [four out of 24 (17%) versus 10 out of 49 (20%); NS]. Predischarge exercise testing, performed in 64 patients (74%), showed myocardial ischemia in 50%; the percentage did not vary significantly between group I and group II patients. Moreover, a positive exercise test was not predictive of major cardiac events at follow-up. CONCLUSION: Transient myocardial ischemia, frequently silent, is not uncommon in the acute phase of myocardial infarction and progressively decreases during the in-hospital stay. Its recognition in the subacute phase of myocardial infarction may lead to the identification of a subset of patients at the highest risk of early major complications, who may benefit from aggressive diagnostic and therapeutic strategies.

Case-Control Studies↗