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R Blasini

Publications and source records attributed to R Blasini.

At least 19 recordsLinked to original sources
PubMed1998

Restenosis rate after intravascular ultrasound-guided coronary stent implantation.

This study was designed to test the hypothesis that patients fulfilling intravascular ultrasound (IVUS) criteria for optimal coronary stent implantation show a reduction in the restenosis rate at 6 months. IVUS guidance for stent dilation may be associated with facilitated stent implantation and an increased acute luminal gain, but it has not yet been determined, whether and to what extent this procedure is associated with a reduction in the restenosis rate. IVUS-guided optimization of Palmaz-Schatz stent placement was performed in 125 consecutive patients, 64 of whom fulfilled IVUS-criteria for optimal stent placement. Another 125 patients served as the non-IVUS control group. In 107 patients (86%) of the non-IVUS control group and 105 patients (84%) of the IVUS group, angiographic follow-up was performed. The IVUS group of patients revealed a significantly lower restenosis rate of 20.9% as compared with 29.9% in the control group (P = 0.033). Patients that met IVUS criteria for optimal stent placement had a larger minimal lumen diameter immediately after stent implantation (3.13 +/- 0.44 vs. 2.95 +/- 0.47 mm; P = 0.045) and at 6-month follow-up (2.23 +/- 0.78 vs. 1.87 +/- 0.76 mm; P = 0.019) as well as a significantly lower restenosis rate (13.5% vs. 28.3%; P = 0.038) as compared with patients that did not fulfil these criteria. Our data suggest that patients fulfilling IVUS criteria for optimal stent placement demonstrate a reduced risk for the development of restenosis. Thus, IVUS investigation identifies factors predictive of restenosis after coronary stent placement.

Adult↗
PubMed1998

Myocardial perfusion scintigraphy to evaluate patients after coronary stent implantation.

UNLABELLED: Coronary stent implantation is an increasingly accepted revascularization method. The 20%-30% restenosis rate during the first 6 mo requires a close follow-up of the patients. Since there is very little data available defining the role of perfusion scintigraphy in the management of this population, the aim of this study was to assess the diagnostic performance of stress myocardial perfusion imaging for detecting restenosis in patients after coronary stent implantation. METHODS: In 82 patients, 93 rest or stress SPECT studies were performed using 201Tl and 99mTc-hexakis-2-methoxyisobutyl isonitrile to evaluate 99 vascular territories with implanted coronary stents. The average interval between the stent implantation and the scintigraphic study was 210.5 +/- 129.6 days. The scintiscans were visually evaluated. A stress-induced perfusion defect with reversibility at rest was used as the criterion for stent restenosis. RESULTS: Coronary angiography revealed a stenosis of > 50% diameter in the region of the stent in 19 arteries, while in 80 arteries there was no evidence of restenosis angiographically. With perfusion scintigraphy, 15/19 vascular territories with restenosed stents showed stress-induced perfusion abnormalities (sensitivity = 79%), while 62/80 territories without restenosis did not (specificity = 78%). In territories without a myocardial infarction (n = 48), sensitivity and specificity values were 8/8 (100%) and 36/44 (82%), and in territories with a myocardial infarction (n = 47) 7/11 (64%) and 26/36 (72%), respectively. Side branch stenosis was fairly frequent in patients without stent restenosis but with a reversible perfusion pattern on their scintiscan (8/18); however, these stenoses were induced infrequently by the stents (3 cases). CONCLUSION: Using the criterion of defect reversibility, stress perfusion SPECT can accurately detect restenoses of coronary artery stents. This method is most accurate for evaluating patients without a previous myocardial infarction in the stented vascular territory.

Coronary Disease↗
PubMed1997

Recovery of myocardial perfusion in acute myocardial infarction after successful balloon angioplasty and stent placement in the infarct-related coronary artery.

OBJECTIVES: This study sought to investigate changes in myocardial perfusion after direct percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (MI). BACKGROUND: After initially successful recanalization of the infarct-related artery, coronary perfusion may deteriorate as a result of reocclusion, distal embolization of platelet aggregates formed at the dilated plaque or microvascular reperfusion injury. This change could offset the benefit from early intervention. METHODS: The study included 19 patients in whom the infarct-related artery was successfully recanalized by PTCA with Palmaz-Schatz stent placement within 24 h after the onset of pain. Basal and papaverine-induced coronary blood flow were assessed by Doppler flow velocity measurements and quantitative coronary angiography. In addition, basal and adenosine-induced myocardial blood flow were measured by nitrogen-13 ammonia positron emission tomography (PET). RESULTS: Immediately after completion of the intervention, the average coronary flow reserve (CR) in the recanalized vessel was 1.56 +/- 0.51; it increased to 2.04 +/- 0.65 at 1 h (p = 0.013) and to 2.66 +/- 0.72 at 2 weeks after reperfusion (p = 0.008, n = 16). PET studies in 12 patients revealed that perfusion defect size and CR in the infarct region (2.19 +/- 0.89 vs. 2.33 +/- 0.86) did not change significantly between day 2 after recanalization and 2 weeks. However, we found significant (p < 0.03) increases in basal (by 26%) and adenosine-induced (by 40%) blood flow in the infarct region. CONCLUSIONS: Despite the persistence of a perfusion defect after successful recanalization of the occluded artery in acute MI, CR of the infarct region improves in most patients within 1 h and further improves within 2 weeks.

Adult↗
PubMed1997

Comparison of angiography and intravascular ultrasound for the assessment of lumen size after coronary stent placement: impact of dilation pressures.

This study was designed to assess the extent of potential discrepancies between intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA) measurement of intrastent minimal luminal diameter and to evaluate the impact of dilation pressures and the balloon:artery ratio on the assessment of the minimal lumen diameter (MLD) by these imaging modalities. IVUS is recommended as an adjunct to angiography to assess stent expansion; however, the extent of potential discrepancies between the two imaging modalities is not well defined. Included were 225 patients in whom coronary Palmaz-Schatz stents were successfully placed after PTCA. IVUS and QCA were performed at the end of the intervention. We compared the MLD assessed by QCA and IVUS in the instent and reference site. The MLD assessed by IVUS and QCA were 2.68 +/- 0.41 mm and 3.08 +/- 0.47 mm (P < 0.001), respectively, at the tightest intrastent site and 3.19 +/- 0.50 mm and 3.17 +/- 0.52 ns at the reference site. There was a correlation between the dilation pressure and the difference between QCA- and IVUS-based intrastent MLD measurement (y = -0.05x + 1.11; r = -0.53; P < 0.0001). At low dilation pressures, a significant difference between the image modalities was found, but after high dilation pressures no discrepancies were detected. No relation was found with the balloon:artery ratio. These data provide clear evidence that in the case of low-pressure dilation, the exclusive reliance on data obtained by QCA will not yield sufficiently accurate information on intrastent MLD, whereas after high dilation pressure, the differences between the imaging modalities are minimized.

Adult↗
PubMed1997

Coronary stent placement in patients with acute myocardial infarction: comparison of clinical and angiographic outcome after randomization to antiplatelet or anticoagulant therapy.

OBJECTIVES: The Intracoronary Stenting and Antithrombotic Regimen (ISAR) trial is a randomized comparison of combined antiplatelet with anticoagulant therapy after coronary Palmaz-Schatz stent placement. The objective of this study was to compare early and late clinical and angiographic outcome in a subgroup of patients with stent placement for acute myocardial infarction. BACKGROUND: Stenting has become a treatment option for acute myocardial infarction, but it is not known which antithrombotic regimen is more adequate after stent implantation. METHODS: One hundred twenty-three patients with successful stenting after acute myocardial infarction were randomized to receive aspirin plus ticlopidine (n = 61) or intense anticoagulant therapy (n = 62). Six-month repeat angiography was performed in 101 (86.3%) eligible patients. RESULTS: During the first 30 days after stenting, patients with antiplatelet therapy had a significantly lower clinical event rate (3.3% vs. 21.0%, p = 0.005) and stent vessel occlusion rate (0% vs. 9.7%, p = 0.03) and a trend to fewer cardiac events (1.6% vs. 9.7%, p = 0.12). After 6 months, the survival rate free of recurrent myocardial infarction was higher in patients with antiplatelet therapy (100% vs. 90.3%, p = 0.03), and the rate of stent vessel occlusion was lower (1.6% vs. 14.5%, p = 0.02). Both groups had comparable restenosis rates (26.5% vs. 26.9%, p = 0.87). CONCLUSIONS: This study demonstrates that combined antiplatelet therapy after stent placement in patients with acute myocardial infarction is associated with an overall better clinical and angiographic outcome than anticoagulant therapy.

Anticoagulants↗
PubMed1997

Antiplatelet effect of ticlopidine after coronary stenting.

OBJECTIVES: This study sought to investigate the contribution of ticlopidine to the inhibition of platelet activation after coronary stent placement. BACKGROUND: After coronary stenting, antiplatelet therapy with aspirin and ticlopidine improves stent patency compared with anticoagulation. However, the specific role of ticlopidine has not been elucidated. METHODS: After successful coronary stent placement, we randomized 22 patients to receive ticlopidine and aspirin (ticlopidine group) and 25 to receive aspirin alone (aspirin group). Surface expression on platelets of the activated fibrinogen receptor and of P-selectin was assessed by flow cytometry. RESULTS: In the aspirin group the percent of platelets with activated fibrinogen receptors increased between days 1 and 5 (p = 0.001), whereas there were no substantial changes in the ticlopidine group. The percent of P-selectin-positive platelets did not change significantly in the aspirin group but decreased in the ticlopidine group (p = 0.019). At day 5 after the intervention, the percent of platelets with activated fibrinogen receptors in the ticlopidine group was significantly lower (median [interquartile range]: 8.5 [3.1 to 17.8] vs. 18.1 [8.5 to 35.5], p = 0.025), and there was a trend to fewer P-selectin-positive platelets than in the aspirin group (5.8 [3.4 to 9.5] vs. 8.8 [4.0 to 15.8], p = 0.073). CONCLUSIONS: Combined antiplatelet therapy with ticlopidine plus aspirin is superior to treatment with aspirin alone in suppressing platelet activation after coronary stenting.

Aged↗
PubMed1996

A randomized comparison of antiplatelet and anticoagulant therapy after the placement of coronary-artery stents.

BACKGROUND: The clinical benefit of coronary-artery stenting performed in conjunction with coronary angioplasty is limited by the risk of thrombotic occlusion of the stent as well as hemorrhagic and vascular complications of intensive anticoagulation. We compared antiplatelet therapy with conventional anticoagulant therapy with respect to clinical outcomes 30 days after coronary-artery stenting. METHODS: After successful placement of Palmaz-Schatz coronary-artery stents, 257 patients were randomly assigned to receive antiplatelet therapy (ticlopidine plus aspirin) and 260 to receive anticoagulant therapy (intravenous heparin, phenprocoumon, and aspirin). The primary cardiac end point was a composite measure reflecting death from cardiac causes or the occurrence of myocardial infarction, aortocoronary bypass surgery, or repeat angioplasty. The primary noncardiac end point comprised death from noncardiac causes, cerebrovascular accident, severe hemorrhage, and peripheral vascular events. RESULTS: Of the patients assigned to antiplatelet therapy, 1.6 percent reached a primary cardiac end point, as did 6.2 percent of those assigned to anticoagulant therapy (relative risk, 0.25; 95 percent confidence interval, 0.06 to 0.77). With antiplatelet therapy, there was an 82 percent lower risk of myocardial infarction than in the anticoagulant-therapy group, and a 78 percent lower need for repeat interventions. Occlusion of the stented vessel occurred in 0.8 percent of the antiplatelet-therapy group and in 5.4 percent of the anticoagulant-therapy group (relative risk, 0.14; 95 percent confidence interval, 0.02 to 0.62). A primary noncardiac end point was reached by 1.2 percent of the antiplatelet-therapy group and 12.3 percent of the anticoagulant-therapy group (relative risk, 0.09; 95 percent confidence interval, 0.02 to 0.31). Hemorrhagic complications occurred only in the anticoagulant-therapy group (in 6.5 percent). An 87 percent reduction in the risk of peripheral vascular events was observed with antiplatelet therapy. CONCLUSIONS: As compared with conventional anticoagulant therapy, combined antiplatelet therapy after the placement of coronary-artery stents reduces the incidence of both cardiac events and hemorrhagic and vascular complications.

Aged↗
PubMed1996

Intravascular ultrasound-guided emergency coronary Palmaz-Schatz stent placement without post-procedural systemic anticoagulation.

OBJECTIVE: To test the efficacy of intravascular ultrasound (IVUS)-guided stent placement and to determine the clinical outcome during the first 30 days in those patients who were treated with antiplatelet therapy rather than anticoagulants because they met the IVUS criteria for optimal stent placement. DESIGN: Prospective observational study. PATIENTS: 126 patients with successful, non-elective Palmaz-Schatz stent placement. INTERVENTIONS: IVUS was performed to assess the attachment of stent struts, the coverage of the dissection, and the intrastent minimal lumen area. MAIN OUTCOME MEASURES: Intrastent lumen area, clinical outcome during the first 30 days. RESULTS: In all patients IVUS showed complete apposition and coverage of the dissection. In 23 patients (18%) the IVUS lumen area criterion was achieved. In 75 patients, further balloon dilatation was performed and in 41 IVUS criteria were finally fulfilled. The minimal intrastent lumen area increased from a mean (SD) of 6.81 (1.15) mm2 to 9.56 (2.61) mm2 (P < or = 0.01) between the first and final IVUS investigations. 64 patients (51%) who met the IVUS criteria were treated with aspirin (100 mg) and ticlopidine (250 mg) twice a day. During the first 30 days none of the following events occurred: death, myocardial infarction, repeat intervention, aortocoronary bypass surgery, and subacute stent thrombosis. CONCLUSION: The additional information provided by IVUS examination helped the operator to decide whether further dilatation was needed after a coronary stent had been placed. For patients who met the IVUS criteria for optimal stent placement, antiplatelet therapy was associated with an excellent clinical outcome during the first 30 days.

Angioplasty, Balloon, Coronary↗
PubMed1995

Correlation between LDA and ultrasound heart catheter measurements in a stenosed arterial model.

Ultrasound heart catheters are used to measure the velocity in coronary arteries. However, the act of introducing a catheter into the vessel disturbs the very flow being measured. We used laser Doppler anemometry to measure the velocity distribution in an axially symmetric model, both with and without a catheter inserted. The catheter reduced the center-line velocity by as much as 60 percent at a distance of 2 mm downstream from the catheter, and by as much as 25 percent at a distance of 10 mm. This means the velocity measured with an ultrasound catheter does not show the maximum velocity of the undisturbed flow in the tube center. In the constriction, however, the measured velocities with the LDA and ultrasound catheter are almost the same. Thus, catheter measurements in the stenosis achieve accurate results. The velocity profile in the stenosed areas is flattened over nearly the whole cross section. The velocity is extremely reduced only close to the wall. The measurements outside of the stenosis lead to large differences which need to be studied carefully in the future. The disturbed flow finally disappeared 15 mm downstream of the catheter. The measurements were done at steady flow using a glycerine water solution with a dynamic viscosity of 4.35 mPas. In future studies, these experiments will be repeated for pulsatile flow conditions using non-Newtonian blood-like fluids.

Blood Flow Velocity↗
PubMed1994

Ultrasound guidance of Palmaz-Schatz intracoronary stenting with a combined intravascular ultrasound balloon catheter.

BACKGROUND: Coronary stenting in conjunction with coronary angioplasty is a valuable tool for treatment of severe coronary dissection and is effective in reducing the frequency of restenoses. Evidence is increasing that the lumen gain within the stent is negatively correlated with the rate of subacute closures and restenoses. Since the assessment of radiolucent coronary stents and complex lumen morphologies by angiography is limited, we hypothesized that the use of a balloon catheter with integrated intravascular ultrasound (IVUS) facility for stent deployment and guidance of its expansion could improve the acute lumen gain without relevant procedural prolongation. METHODS AND RESULTS: Deployment of a single Palmaz-Schatz coronary stent with the combined imaging balloon catheter alone was successful in 18 of 20 patients eligible for this study. Corresponding measurements of minimal lumen diameter (MLD) by angiography and IVUS could be performed in 16 patients, revealing a close correlation between the two methods within the reference segments (3.10 +/- 0.38 and 3.08 +/- 0.43 mm, r = .79). Despite an adequate angiographic result in most patients after stent deployment, IVUS showed smaller MLD within the stented segment (2.15 +/- 0.23 mm) compared with angiography (2.63 +/- 0.26 mm, P < .0001) with a poor correlation (r = .27). To achieve IVUS criteria for optimal stent expansion (ratio of 0.9 between IVUS-assessed cross-sectional area of stent and reference segment), an average of three additional balloon inflations with higher pressure and/or a larger balloon diameter were performed without adverse effects in 15 of 16 patients who initially did not fulfill these criteria. This resulted in a significant increase in stent MLD to 2.63 +/- 0.27 mm (IVUS, P < .0001 versus initial MLD) and 2.89 +/- 0.32 mm (angiography, P < .0002 versus initial MLD) and a better correlation between the two methods (r = .60). The IVUS guidance led to a 40 +/- 15% increase of the minimal stent cross-sectional area with an additional time consumption of 21 minutes on average. CONCLUSIONS: This study demonstrates the application of a combined imaging balloon catheter for delivery and ultrasound-guided expansion of Palmaz-Schatz coronary stents. IVUS offered a comprehensive insight into the stented coronary segments, revealing a substantial overestimation of stent dimensions by angiography. IVUS guidance led to a significant improvement of stent expansion. This additional lumen gain, which was not discernible by angiography in most patients, might result in a reduction of subacute stent thromboses as well as restenoses.

Adult↗
PubMed1994

Four-year experience with Palmaz-Schatz stenting in coronary angioplasty complicated by dissection with threatened or present vessel closure.

BACKGROUND: Abrupt vessel closure after percutaneous transluminal coronary angioplasty (PTCA) is associated with major adverse events. Different surgical and nonsurgical approaches have been advocated to treat or prevent this complication. This study summarizes our 4-year experience with Palmaz-Schatz stenting for the management of 339 patients with present or threatened occlusion after PTCA. METHODS AND RESULTS: Stent implantation was attempted in a total of 339 and 4959 patients with PTCA during the study period and was successful in 327 (96.5%). During the follow-up, events like death, myocardial infarction, need for revascularization (bypass surgery and repeat in-stent angioplasty), and major vascular complications were recorded. Angiographic follow-up at 6 months was performed in 89.3% of the eligible patients. As part of an initial policy, stenting was intended as a bridge to nonemergency bypass surgery in 26 patients. In 301 patients for whom stenting was intended as permanent treatment, early clinical course (first 4 weeks) was characterized by a 1.3% cardiac mortality and a 4.0% nonfatal myocardial infarction rate; bypass surgery was necessary in 1%, and 6.3% required early repeat PTCA. Surgical repair for peripheral vascular complications was required in 5.6%, and major bleeding events were encountered in 9%. The incidence of subacute stent closure was 6.9%, with subsequent recanalization successful in 86%; subacute stent closure was predicted by presence of vessel occlusion before stenting and localization of the stent in a vessel other than the right coronary artery. Survival rate at 2 years was 95.4%, survival without myocardial infarction was 91.1%, and event-free survival was 70.7%. Survival at 2 years was lower for patients with stents in bypass vein grafts and with myocardial infarction after stenting. Six-month control angiography revealed a restenosis rate of 29.6%. CONCLUSIONS: Patients with present or threatened occlusion after PTCA may benefit from Palmaz-Schatz stenting. It is associated with a low mortality and myocardial infarction rate and with a long-term event-free rate comparable to that of uncomplicated PTCA.

Adult↗
PubMed1993

Functional changes in left ventricular hypertrophy: diagnosis of impaired diastolic function in patients with hypertension.

Left ventricular hypertrophy is usually associated with impaired left ventricular diastolic function which can be characterised by an altered pressure volume relationship. Since diastolic flow velocities are closely related to the difference in pressure between the left atrium and left ventricle, parameters of diastolic function can be determined by Doppler echocardiography. However, the pressure difference is additionally influenced by factors which have no relation to left ventricular diastolic function. These include preload, afterload, inotropy, heart rate and left ventricular systolic function. Despite these limitations, Doppler echocardiography is a valuable tool to diagnose therapeutic effects on diastolic function in patients with left ventricular hypertrophy.

Diastole↗
PubMed1993

Intravascular ultrasound assessment of the balloon-expandable Palmaz-Schatz coronary stent.

BACKGROUND: Coronary stenting is an effective method for the treatment of acute coronary dissection and restenosis. In the comprehensive assessment of restenosis and of the complex interaction between coronary stent and vessel wall, coronary arteriography has significant limitations. Intravascular ultrasound as a high-resolution tomographic imaging method is a promising tool for resolving these limitations. METHODS: A 3.5, 5.0 or 5.5F, 20 MHz multi-element ultrasound catheter was used in 27 patients who had received a Palmaz-Schatz coronary stent for the treatment of symptomatic coronary dissection. Intravascular ultrasound study was performed during routine follow-up arteriography at 3-10 months in all 27 patients and had also been performed in four patients during stent deployment. Four patients with restenosis within the stent were re-investigated 3 months later after repeat angioplasty. RESULTS: Complete analysis of the stented coronary segment could be performed in 34 out of 35 studies (97%); no adverse effects occurred. The three layer appearance of the vessel wall was not discernible in most patients because of a complex and often eccentric lesion surrounding the stent resulting in an asymmetrical arrangement of stent filaments. The beginning and the end of the stent, the central strut, and the overlap of a double stent could be well assessed. Luminal diameters ranged from 1.95 to 4.15 mm and cross-sectional areas from 3.83 to 10.85 mm2. Correlations with quantitative arteriography revealed r-values of 0.58 for diameter and 0.59 for area. A stent-covering layer, indicative of neointima, was clearly visible in all patients during follow-up arteriography with a diameter of 0.10-0.95 mm (mean 0.25 +/- 0.15 mm), which resulted in a reduction of 2-63% in the cross-sectional area of the vessel. This layer did not exceed a thickness of 0.4 mm in asymptomatic patients. CONCLUSIONS: This study demonstrates the safe and feasible application of intravascular ultrasound in patients with stented coronary lesions. Differences between the angiographic and ultrasonic measurements are presumably the result of the limitations of radiography in complex and eccentric lesions. Intracoronary ultrasound provides a unique comprehensive assessment of stent expansion, neointimal proliferation, and restenosis mechanisms. Thus, intravascular ultrasound may also have implications regarding the indication for, and optimal deployment of, intracoronary stents.

Aged↗
PubMed1992

[Intravascular ultrasound (IVUS): the assessment of tumor infiltration into the vascular wall].

The demonstration or exclusion of tumour infiltration into a vessel wall is made possible by IVUS. This was performed 25 times in 23 patients using a 20 MHz probe where there was suspicion of tumour infiltration on the basis of CT, MRI or angiography. IVUS proved very suitable for clarifying the situation, making direct intravascular evaluation of the affected vessel possible. In 10 cases where surgery was performed, the demonstration or exclusion of tumour infiltration into a vein was confirmed operatively in every case. Further experience is necessary before the value of the method for diagnosing early arterial infiltration can be judged.

Adult↗