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Biomedical subjects

M Sabaté

Publications and source records attributed to M Sabaté.

At least 37 records · Page 2Linked to original sources
PubMed2000

Fate of stent-related side branches after coronary intervention in patients with in-stent restenosis.

OBJECTIVES: We sought to assess the fate of stent (ST)-related side branches (SB) after coronary intervention in patients with in-ST restenosis. BACKGROUND: In-ST restenosis constitutes a therapeutic challenge. Although the fate of lesion-related SB after conventional angioplasty or initial coronary stenting is well established, the outcome of ST-related SB in patients with in-ST restenosis undergoing repeat intervention is unknown. METHODS: One hundred consecutive patients (age 61 +/- 11 years, 22 women) undergoing repeat intervention for in-ST restenosis (101 ST) were prospectively studied. Two hundred and twenty-six SB spanned by the ST were identified. The SB size, type, ostium involvement, location within the ST and take-off angle were evaluated. The SB TIMI (Thrombolysis in Myocardial Infarction trial) flow grade was studied in detail before, during, immediately after the procedure, and at late angiography. RESULTS: Occlusion (TIMI flow grade = 0) was produced in 24 (10%) SB, whereas some degree of flow deterioration (> or = 1 TIMI flow grade) was observed in 57 SB (25%). The SB occlusion was associated with non-Q wave myocardial infarction in two patients (both had large and diseased SB). Side-branch occlusion at the time of initial stenting (RR [relative risk] 11.1, 95% CI [confidence interval] 3.5-35.5, p < 0.001), diabetes (RR 3.5, 95% CI 1.1-10.5, p = 0.02), SB ostium involvement (RR 5.0, 95% CI 1.4-17.2, p = 0.004), baseline SB TIMI flow grade <3 (RR 5.5, 95% CI 1.7-18.1, p = 0.005), and restenosis length (RR 1.05 95% CI 1.01-1.11, p = 0.03) were identified as independent predictors of SB occlusion. Late angiography in 19 initially occluded SB revealed that 17 (89%) were patent again. The long-term clinical event-free survival (81% vs. 82% at two years) in patients with and without initial SB occlusion was similar. CONCLUSIONS: Occlusion or flow deterioration of SB spanned by the ST is relatively common during repeat intervention for in-ST restenosis. Several factors (mainly anatomic features) are useful predictors of this event. However, most SB occlusions are clinically silent and frequently reappear at follow-up.

Adult↗
PubMed2000

Three-dimensional intravascular ultrasound assessment of noninjured edges of beta-irradiated coronary segments.

BACKGROUND: The "edge effect," late lumen loss at the margins of the treated segment, has become an important issue in the field of coronary brachytherapy. The aim of the present study was to assess the edge effect in noninjured margins adjacent to the irradiated segments after catheter-based intracoronary beta-irradiation. METHODS AND RESULTS: Fifty-three vessels were assessed by means of 3-dimensional intravascular ultrasound after the procedure and at 6- to 8-month follow-up. Fourteen vessels (placebo group) did not receive radiation (sham source), whereas 39 vessels were irradiated. In the irradiated group, 48 edges (5 mm in length) were identified as noninjured, whereas 18 noninjured edges were selected in the placebo group. We compared the volumetric intravascular ultrasound measurements of the noninjured edges of the irradiated vessels with the fully irradiated nonstented segments (IRS, n=27) (26-mm segments received the prescribed 100% isodose) and the noninjured edges of the vessels of the placebo patients. The lumen decreased (6 mm(3)) in the noninjured edges of the irradiated vessels at follow-up (P:=0. 001). We observed a similar increase in plaque volume in all segments: noninjured edges of the irradiated group (19.6%), noninjured edges of the placebo group (21.5%), and IRS (21.0%). The total vessel volume increased in the IRS in the 3 groups. No edge segment was subject to repeat revascularization. CONCLUSIONS: The edge effect occurs in the noninjured margins of radiation source train in both irradiated and placebo patients. Thus, low-dose radiation may not play an important role in this phenomenon, whereas nonmeasurable device injury may be considered a plausible alternative explanation.

Angioplasty, Balloon↗
PubMed2000

Positive geometric vascular remodeling is seen after catheter-based radiation followed by conventional stent implantation but not after radioactive stent implantation.

BACKGROUND: Recent reports demonstrate that intracoronary radiation affects not only neointimal formation but also vascular remodeling. Radioactive stents and catheter-based techniques deliver radiation in different ways, suggesting that different patterns of remodeling after each technique may be expected. METHODS AND RESULTS: We analyzed remodeling in 18 patients after conventional stent implantation, 16 patients after low-activity radioactive stent implantation, 16 patients after higher activity radioactive stent implantation, and, finally, 17 patients who underwent catheter-based radiation followed by conventional stent implantation. Intravascular ultrasound with 3D reconstruction was used after stent implantation and at the 6-month follow-up to assess remodeling within the stent margins and at its edges. Preprocedural characteristics were similar between groups. In-stent neointimal hyperplasia (NIH) was inhibited by high-activity radioactive stent implantation (NIH 9.0 mm(3)) and by catheter-based radiation followed by conventional stent implantation (NIH 6.9 mm(3)) compared with low-activity radioactive stent implantation (NIH 21.2 mm(3)) and conventional stent implantation (NIH 20.8 mm(3)) (P:=0.008). No difference in plaque or total vessel volume was seen behind the stent in the conventional, low-activity, or high-activity stent implantation groups. However, significant increases in plaque behind the stent (15%) and in total vessel volume (8%) were seen in the group that underwent catheter-based radiation followed by conventional stent implantation. All 4 groups demonstrated significant late lumen loss at the stent edges; however, edge restenosis was seen only in the group subjected to high-activity stent implantation and appeared to be due to an increase in plaque and, to a lesser degree, to negative remodeling. CONCLUSIONS: Distinct differences in the patterns of remodeling exist between conventional, radioactive, and catheter-based radiotherapy with stenting.

Adult↗
PubMed2000

Geographic miss: a cause of treatment failure in radio-oncology applied to intracoronary radiation therapy.

BACKGROUND: A recognized limitation of endovascular beta-radiation therapy is the development of new stenosis at the edges of the irradiated area. The combination of injury and low-dose radiation may be the precursor of this phenomenon. We translated the radio-oncological concept of "geographic miss" to define cases in which the radiation source did not fully cover the injured area. The aims of the study were to determine the incidence and causes of geographic miss and evaluate the impact of this inadequate treatment on the outcome of patients treated with intracoronary beta-radiation. METHODS AND RESULTS: We analyzed 50 consecutive patients treated with beta-radiation after percutaneous coronary intervention. The prescribed dose ranged between 12 and 20 Gy at 2 mm from the source axis. By means of quantitative coronary angiography, the irradiated segment (IRS) and both edges were studied before and after intervention and at 6-month follow-up. Edges that were injured during the procedure constituted the geographic miss edges. Twenty-two edges were injured during the intervention, mainly because of procedural complications that extended the treatment beyond the margins of the IRS. Late loss was significantly higher in geographic miss edges than in IRSs and uninjured edges (0.84+/-0.6 versus 0.15+/-0.4 and 0.09+/-0.4 mm, respectively; P<0.0001). Similarly, restenosis rate was significantly higher in the injured edges (10% within IRS, 40.9% in geographic miss edges, and 1.9% in uninjured edges; P<0.001). CONCLUSIONS: These data support the hypothesis that the combination of injury and low-dose beta-radiation induces deleterious outcome.

Angioplasty, Balloon, Coronary↗
PubMed2000

Residual plaque burden, delivered dose, and tissue composition predict 6-month outcome after balloon angioplasty and beta-radiation therapy.

BACKGROUND: Inhomogeneity of dose distribution and anatomic aspects of the atherosclerotic plaque may influence the outcome of irradiated lesions after balloon angioplasty (BA). We evaluated the influence of delivered dose and morphological characteristics of coronary stenoses treated with beta-radiation after BA. METHODS AND RESULTS: Eighteen consecutive patients treated according to the Beta Energy Restenosis Trial 1.5 were included in the study. The site of angioplasty was irradiated with the use of a beta-emitting (90)Sr/(90)Y source. With the side branches used as anatomic landmarks, the irradiated area was identified and volumetric assessment was performed by 3D intracoronary ultrasound imaging after treatment and at 6 months. The type of tissue, the presence of dissection, and the vessel volumes were assessed every 2 mm within the irradiated area. The minimal dose absorbed by 90% of the adventitial volume (D(v90)Adv) was calculated in each 2-mm segment. Diffuse calcified subsegments and those containing side branches were excluded. Two hundred six coronary subsegments were studied. Of those, 55 were defined as soft, 129 as hard, and 22 as normal/intimal thickening. Plaque volume showed less increase in hard segments as compared with soft and normal/intimal thickening segments (P<0.0001). D(v90)Adv was associated with plaque volume at follow-up after a polynomial equation with linear and nonlinear components (r = 0.71; P = 0.0001). The multivariate regression analysis identified the independent predictors of the plaque volume at follow-up: plaque volume after treatment, D(v90)Adv, and type of plaque. CONCLUSIONS: Residual plaque burden, delivered dose, and tiss composition play a fundamental role in the volumetric outcome at 6-month follow-up after beta-radiation therapy and BA.

Angioplasty, Balloon, Coronary↗
PubMed2000

Coronary bifurcation stenting using dedicated bifurcation stents.

We report three cases of successful implantation of three different stents specially designed for bifurcation lesions, guided by intracoronary ultrasound. The BARD and AVE are true bifurcated stents for side-branch access and the NIR-Side Royal is a single modified NIR stent with an aperture to allow provisional bifurcation stenting. These designs introduce a new era in percutaneous management of coronary bifurcation lesions. Cathet. Cardiovasc. Intervent. 49:105-111, 2000.

Adult↗
PubMed2000

Guidewire-induced coronary pseudostenosis as a source of error during physiological guidance of stent deployment.

Coronary pseudostenoses are a known result of the interaction between tortuous vessels and guidewires and are generally handled by the interventionalist as inocuous side effects of intracoronary instrumentation. The present report demonstrates that pseudostenosis may have hemodynamic relevance and may constitute an important source of error when physiological guidance of percutaneous procedures is performed using sensor-tipped guidewires.

Aged↗
PubMed2000

Predictive factors and long-term evolution of early endothelial dysfunction after cardiac transplantation.

BACKGROUND: Abnormal coronary vasomotion appears to be a common finding after heart transplantation (HTx). However, the pathophysiology and outcome of this functional disturbance remains poorly understood. Aims of the study were to determine the prevalence, predictive factors and long-term evolution of endothelial dysfunction after cardiac transplantation. METHODS: The endothelium-dependent coronary vasomotion of 50 patients, who showed angiographically normal coronary arteries, were studied early (at 3 +/- 1 months) and at follow-up (16 +/- 5 months) after HTx. Endothelial function was studied by selective infusion of serial doses of acetylcholine (ACh) (10(-8), 10(-7)and 10(-6) mol/l) in the left anterior descending coronary artery. Changes in mean luminal diameter after the infusion of each dose were evaluated by quantitative coronary angiography (QCA). RESULTS: At early study, 17 patients (34%) showed a vasoconstriction after maximal dose of ACh (-13.3 +/- 13%) indicative of endothelial dysfunction. Logistic regression analysis identified the following variables as independent predictors of early endothelial dysfunction: donor inotropic support (p = 0.004), female donor (p = 0.04) and rejection at the time of the study (p = 0.01). Forty-one patients were re-studied at follow-up. Nine of them (22%) presented endothelial dysfunction. Early endothelial dysfunction was restored in 6 patients (43%) at follow-up. The number of episodes of rejection was the only variable associated to late endothelial dysfunction. CONCLUSIONS: Endothelial dysfunction is a common finding after cardiac transplantation. The pathogenesis of this functional disturbance appears to be donor-related and immune-mediated. The reversibility of this phenomenon observed at follow-up suggests the episodic nature of the immunologic injury.

Acetylcholine↗
PubMed2000

Relationship between tensile stress and plaque growth after balloon angioplasty treated with and without intracoronary beta-brachytherapy.

AIMS: We investigated the influence of tensile stress on plaque growth after balloon angioplasty with and without beta-radiation therapy. METHODS AND RESULTS: Thirty-one consecutive patients successfully treated with balloon angioplasty were analysed qualitatively and quantitatively by means of an ECG-gated three-dimensional intravascular ultrasound post-procedure and at follow-up. Eighteen patients were irradiated with catheter-based beta-radiation ((90)Sr/(90)Y source) and 13 were not (control). Studied segments were divided into 2 mm subsegments. Thus 184 irradiated and 111 non-irradiated subsegments were included. Tensile stress was calculated according to Laplace's law. The radiation dose was calculated by means of dose-volume histograms. Plaque growth was positively correlated to tensile stress in both the radiation and control groups (r=0.374, P=0.0001 and r=0.305, P=0.001). Low-dose subsegments (<6 Gy) had a significant correlation (r=0.410, P=0.0001) whereas no correlation was observed in the effective-dose subsegments (> or = 6 Gy). Multivariate analysis identified tensile stress as the only independent predictor of plaque increase in non-irradiated subsegments, whereas actual dose and plaque morphology were stronger predictors in irradiated subsegments. CONCLUSION: The results of this study suggest that plaque growth is related to tensile stress after balloon angioplasty. Intracoronary brachytherapy may alter the biophysical process on plaque growth when the prescribed dose is effectively delivered.

Aged↗
PubMed2000

Cloning and sequence of the gene encoding a novel cefotaxime-hydrolyzing beta-lactamase (CTX-M-9) from Escherichia coli in Spain.

A new CTX-M-type beta-lactamase (CTX-M-9) has been cloned from a clinical cefotaxime-resistant Escherichia coli strain. Despite the close identity that exists between the CTX-M-9 and Toho-2 beta-lactamases (88%), the 35 amino acids located between residues Ala-185 and Ala-219 are totally different in both enzymes. Outside of this region there are only six amino acids substitutions between both proteins.

Amino Acid Sequence↗
PubMed2000

[Intravascular ultrasound in cardiology].

Intravascular ultrasound (IVUS) is a clinically useful tool that provides cross-sectional images of the coronary arterial lumen and wall. Diagnostic applications of IVUS include the evaluation of ambiguous lesions on angiography particularly at the bifurcations. IVUS is also useful in the assessment of coronary vasculopathy in cardiac transplant patients or it can help to diagnose abnormalities such as syndrome X or coronary artery spasm. IVUS can optimize the performing of percutaneous coronary interventions, especially stent implantation. It represents as well an optimal tool for assessing regression of atherosclerosis. Three-dimensional reconstruction, elastography and imaging guide wires are some of the recent advances in the field of intravascular ultrasound.

Angioplasty, Balloon, Coronary↗
PubMed2000

Successful sealing of an angioplasty-related saphenous vein graft rupture with a PTFE-covered stent.

A patient developed severe hemodynamic compromise after saphenous vein graft rupture during high-pressure coronary stent deployment. Immediate balloon inflation followed by implantation of a polytetrafluoroethylene-covered stent solved the problem. The next day, follow-up angiography confirmed persistent sealing of the rupture site. Clinical and angiographic features of vessel rupture during coronary angioplasty as well as several therapeutic options for this complication are discussed.

Aged↗
PubMed2000

Restenosis and Brachytherapy.

Intracoronary radiation therapy has been developed in an attempt to decrease restenosis after balloon angioplasty and stent implantation. Two parallel technologies, one employing radioactive stents, the other catheter-based radiation (using either beta- or gamma-emitters), have been the subject of both animal and human studies. In vivo intravascular ultrasound imaging studies have helped us to determine the morphologic effect of brachytherapy on the vessel wall. This article is aimed at revising the potential and limitations of this new technique and summarizing the results of the currently reported clinical trials.

Journal Article↗
PubMed1999

beta-Particle-emitting radioactive stent implantation. A safety and feasibility study.

BACKGROUND: This study represents the Heart Center Rotterdam's contribution to the Isostents for Restenosis Intervention Study, a nonrandomized multicenter trial evaluating the safety and feasibility of the radioactive Isostent in patients with single coronary artery disease. Restenosis after stent implantation is primarily caused by neointimal hyperplasia. In animal studies, beta-particle-emitting radioactive stents decrease neointimal hyperplasia by inhibiting smooth muscle cell proliferation. METHODS AND RESULTS: The radioisotope (32)P, a beta-particle emitter with a half-life of 14.3 days, was directly embedded into the Isostent. The calculated range of radioactivity was 0.75 to 1.5 microCi. Quantitative coronary angiography measurements were performed before and after the procedure and at 6-month follow-up. A total of 31 radioactive stents were used in 26 patients; 30 (97%) were successfully implanted, and 1 was embolized. Treated lesions were in the left anterior descending coronary artery (n=12), the right coronary artery (n=8), or the left circumflex coronary artery (n=6). Five patients received additional, nonradioactive stents. Treated lesion lengths were 13+/-4 mm, with a reference diameter of 2.93+/-0. 47 mm. Minimum lumen diameter increased from 0.87+/-0.28 mm preprocedure to 2.84+/-0.35 mm postprocedure. No in-hospital adverse cardiac events occurred. All patients received aspirin indefinitely and ticlopidine for 4 weeks. Twenty-three patients (88%) returned for 6-month angiographic follow-up; 17% of them had in-stent restenosis, and 13% had repeat revascularization. No restenosis was observed at the stent edges. Minimum lumen diameter at follow-up averaged 1.85+/-0.69 mm, which resulted in a late loss of 0.99+/-0. 59 mm and a late loss index of 0.53+/-0.35. No other major cardiac events occurred during the 6-month follow-up. CONCLUSIONS: The use of radioactive stents with an activity of 0.75 to 1.5 microCi is safe and feasible.

Adult↗
PubMed1999

Preserved endothelium-dependent vasodilation in coronary segments previously treated with balloon angioplasty and intracoronary irradiation.

BACKGROUND: Abnormal endothelium-dependent coronary vasomotion has been reported after balloon angioplasty (BA), as well as after intracoronary radiation. However, the long-term effect on coronary vasomotion is not known. The aim of this study was to evaluate the long-term vasomotion of coronary segments treated with BA and brachytherapy. METHODS AND RESULTS: Patients with single de novo lesions treated either with BA followed by intracoronary beta-irradiation (according to the Beta Energy Restenosis Trial-1.5) or with BA alone were eligible. Of these groups, those patients in stable condition who returned for 6-month angiographic follow-up formed the study population (n=19, irradiated group and n=11, control group). Endothelium-dependent coronary vasomotion was assessed by selective infusion of serial doses of acetylcholine (ACh) proximally to the treated area. Mean luminal diameter was calculated by quantitative coronary angiography both in the treated area and in distal segments. Endothelial dysfunction was defined as a vasoconstriction after the maximal dose of ACh (10(-6) mol/L). Seventeen irradiated segments (89.5%) demonstrated normal endothelial function. In contrast, 10 distal nonirradiated segments (53%) and 5 control segments (45%) demonstrated endothelium-dependent vasoconstriction (-19+/-17% and -9.0+/-5%, respectively). Mean percentage of change in mean luminal diameter after ACh was significantly higher in irradiated segments (P=0.01). CONCLUSIONS: Endothelium-dependent vasomotion of coronary segments treated with BA followed by beta-radiation is restored in the majority of stable patients at 6-month follow-up. This functional response appeared to be better than those documented both in the distal segments and in segments treated with BA alone.

Acetylcholine↗
PubMed1999

Geometric vascular remodeling after balloon angioplasty and beta-radiation therapy: A three-dimensional intravascular ultrasound study.

BACKGROUND: Endovascular radiation appears to inhibit intimal thickening after overstretching balloon injury in animal models. The effect of brachytherapy on vascular remodeling is unknown. The aim of the study was to determine the evolution of coronary vessel dimensions after intracoronary irradiation after successful balloon angioplasty in humans. METHODS AND RESULTS: Twenty-one consecutive patients treated with balloon angioplasty and beta-radiation according to the Beta Energy Restenosis Trial-1.5 were included in the study. Volumetric assessment of the irradiated segment and both edges was performed after brachytherapy and at 6-month follow-up. Intravascular ultrasound images were acquired by means of ECG-triggered pullback, and 3-D reconstruction was performed by automated edge detection, allowing the calculation of lumen, plaque, and external elastic membrane (EEM) volumes. In the irradiated segments, mean EEM and plaque volumes increased significantly (451+/-128 to 490.9+/-159 mm(3) and 201.2+/-59 to 241.7+/-74 mm(3); P=0.01 and P=0.001, respectively), whereas luminal volume remained unchanged (250.8+/-91 to 249.2+/-102 mm(3); P=NS). The edges demonstrated an increase in mean plaque volume (26.8+/-12 to 32. 6+/-10 mm(3), P=0.0001) and no net change in mean EEM volume (71. 4+/-24 to 70.9+/-24 mm(3), P=NS), resulting in a decrease in mean luminal volume (44.6+/-16 to 38.3+/-16 mm(3), P=0.01). CONCLUSIONS: A different pattern of remodeling is observed in coronary segments treated with beta-radiation after successful balloon angioplasty. In the irradiated segments, the adaptive increase of EEM volume appears to be the major contributor to the luminal volume at follow-up. Conversely, both edges showed an increase in plaque volume without a net change in EEM volume.

Angioplasty, Balloon↗
PubMed1999

Late coronary occlusion after intracoronary brachytherapy.

BACKGROUND: Intracoronary brachytherapy appears to be a promising technology to prevent restenosis. Presently, limited data are available regarding the late safety of this therapeutic modality. The aim of the study was to determine the incidence of late (>1 month) thrombosis after PTCA and radiotherapy. METHODS AND RESULTS: From April 1997 to March 1999, we successfully treated 108 patients with PTCA followed by intracoronary beta-radiation. Ninety-one patients have completed at least 2 months of clinical follow-up. Of these patients, 6.6% (6 patients) presented with sudden thrombotic events confirmed by angiography 2 to 15 months after intervention (2 balloon angioplasty and 4 stent). Some factors (overlapping stents, unhealed dissection) may have triggered the thrombosis process, but the timing of the event is extremely unusual. Therefore, the effect of radiation on delaying the healing process and maintaining a thrombogenic coronary surface is proposed as the most plausible mechanism to explain such late events. CONCLUSIONS: Late and sudden thrombosis after PTCA followed by intracoronary radiotherapy is a new phenomenon in interventional cardiology.

Aged↗