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R Bonan

Publications and source records attributed to R Bonan.

At least 19 recordsLinked to original sources
PubMed2003

Reno, a European postmarket surveillance registry, confirms effectiveness of coronary brachytherapy in routine clinical practice.

PURPOSE: To assess, by a European registry trial, the clinical event rate in patients with discrete stenotic lesions of coronary arteries (de novo or restenotic) in single or multiple vessels (native or bypass grafts) treated with beta-radiation. MATERIALS AND METHODS: Between April 1999 and September 2000, 1098 consecutive patients treated in 46 centers in Europe and the Middle East with the Novoste Beta-Cath System were included in Registry Novoste (RENO). RESULTS: Six-month follow-up data were obtained for 1085 patients. Of 1174 target lesions, 94.1% were located in native vessels and 5.9% in a bypass graft; 17.7% were de novo lesions, 4.1% were restenotic, and 77.7% were in-stent restenotic lesions. Intravascular brachytherapy was technically successful in 95.9% of lesions. Multisegmental irradiation, using a manual pullback stepping maneuver to treat longer lesions, was used in 16.3% of the procedures. The in-hospital rate of major adverse cardiac events was 1.8%. At 6 months, the rate was 18.7%. Angiographic follow-up was available for 70.4% of the patients. Nonocclusive restenosis was seen in 18.8% and total occlusion in 5.7% of patients. A combined end point for late (30-180 days) definitive or suspected target vessel closure was reached in 5.4%, but with only 2% of clinical events. Multivariate analysis was performed for major adverse cardiac events and late thrombosis. CONCLUSIONS: Data obtained from the multicenter RENO registry study, derived from a large cohort of unselected consecutive patients, suggest that the good results of recent randomized controlled clinical trials can be replicated in routine clinical practice.

Aged↗
PubMed2003

A multicentre European registry of intraluminal coronary beta brachytherapy.

AIMS: To assess the feasibility, safety and effectiveness of intravascular brachytherapy (VBT) in routine clinical practice. METHODS AND RESULTS: Between April 1999 and September 2000, 1098 consecutive patients treated in 46 European centres by intraluminal irradiation using a Sr/Y(90)source train (BetaCath, Novoste, GA) were included in a registry, and follow-up data were obtained for 98.8% of them after 6.3+/-2.4 months. Eight hundred and forty (76.5%) patients were males, and mean age was 62.0+/-10.2 years. Two hundred and seventy-one (26.9%) had unstable angina, and 256 (23.5%) were diabetics. Nine hundred and thirteen lesions (77.7%) were the result of in-stent restenosis, 208 (17.7%) were de novo lesions and 48 (4.1%) non-stented restenotic lesions. Mean estimated reference diameter was 3.2+/-0.5mm and mean estimated lesion length was 19.0+/-11.8mm. The prescribed radiation dose was 18.8+/-3.2Gy. Multivessel irradiation was done in 6.2% of cases, and a new stent was implanted in 29.6% of cases. Most patients received 6 or 12 months of combined aspirin and thienopyridin treatment after the procedure. Technical success was obtained in 95.9% of treated lesions, and the in-hospital major adverse cardiac event (MACE) rate was 1.8%. At follow-up, the MACE rate was 18.7% (1.9% deaths from any cause, 2.6% AMI, 13.3% TVR by PCI and 3.3% TVR by CABG). CONCLUSION: The major current application of VBT is the treatment of in-stent restenosis. The good results of VBT observed in recent randomized controlled trials can be reproduced in clinical practice.

Aged↗
PubMed2003

Clinical and angiographic acute and follow up results of intracoronary beta brachytherapy in saphenous vein bypass grafts: a subgroup analysis of the multicentre European registry of intraluminal coronary beta brachytherapy (RENO).

OBJECTIVE: To assess clinically and angiographically the feasibility, safety, and effectiveness of vascular brachytherapy (VBT) in saphenous vein bypass grafts (SVG). PATIENTS AND METHODS: 67 of 1098 (6.1%) consecutive patients of the European registry of intraluminal coronary beta brachytherapy underwent treatment for 68 SVG lesions by VBT using a Sr/Y(90) source train (BetaCath). Clinical follow up data were obtained for all of them after a mean (SD) of 6.3 (2.4) months and angiographic follow up was performed in 61 patients (91.0%) after 6.9 (2.0) months. RESULTS: 58 (86.6%) patients were men, their mean (SD) age was 66 (10) years, 28 (41.8%) had unstable angina, and 21 (31.3%) had diabetes. Fifty three (77.9%) lesions were in-stent restenosis, 13 (19.1%) de novo lesions, and 2 (3.0%) non-stented restenotic lesions. Mean (SD) reference diameter before the intervention was 4.19 (0.52) mm, mean (SD) lesion length was 23.56 (20.38) mm, and mean (SD) minimum lumen diameter measured 0.73 (0.62) mm. Mean (SD) acute gain was 3.02 (0.88) mm. The prescribed radiation dose was 20.1 (3.2) Gy. Pullback manoeuvres were performed in 17 (25.0%) of cases. Most patients received combined aspirin and thienopyridin treatment for 6 or 12 months after the procedure. Technical success was obtained in 62 (91.2%) treated lesions and in-hospital major adverse cardiac events occurred in 4.5%. At follow up, mean (SD) reference diameter was 4.20 (0.53) mm, minimum lumen diameter 2.94 (1.50) mm, and late loss 0.86 (1.25) mm. The overall major adverse cardiac events rate was 26.7%. CONCLUSION: VBT of SVG is feasible and safe. At follow up the reintervention rate and cardiac morbidity and mortality seem to be favourable, considering that interventions in SVG usually are associated with the highest risks.

Aged↗
PubMed2002

High-dose intravascular beta-radiation after de novo stent implantation induces coronary artery spasm.

BACKGROUND: Intracoronary brachytherapy is effective in preventing restenosis after coronary interventions. However, in vitro and animal studies have shown that irradiation produces immediate and sustained endothelial dysfunction. This study assesses the clinical relevance of impaired vasomotoric function induced by brachytherapy. METHODS AND RESULTS: We analyzed the occurrence of postradiation coronary artery spasms in 1 animal study and 2 clinical trials investigating the effects of high-dose intracoronary beta-radiation after de novo coronary artery stenting. Irradiated segments (IRSs) proximal and distal to the stent were studied by quantitative coronary angiography after stenting, after radiation, and at the end of the procedure. There was an 67% overall incidence of coronary artery spasm in the IRSs immediately after beta-radiation compared with 9% after sham treatment (P<0.001). Whereas in most cases this phenomenon was only minor or moderate, in 12 cases, 4 (22%) animals and 8 (28%) patients, severe coronary spasm (>90% diameter stenosis) with significant ECG-changes or hemodynamic instability was observed. Relief of spasms was protracted (mean time until complete relief of spasm 423+/-122 seconds) and required repetitive intracoronary administration of nitroglycerin (mean dose: 1.2+/-0.6 mg). CONCLUSIONS: Vasoconstriction is a frequent reaction of coronary arteries after high-dose intracoronary beta-radiation, necessitating repetitive administration of vasodilators.

Animals↗
PubMed2002

Impact of final coronary flow velocity reserve on late outcome following stent implantation.

Aims To assess whether coronary flow velocity reserve following stent implantation is predictive of the subsequent need of target lesion revascularization. Methods and Results The outcome was examined of 417 patients enrolled in a multicentre prospective randomized study (DESTINI), who received a successful single vessel stent implantation in native coronary arteries and in whom coronary flow velocity reserve was measured. Logistic regression analysis and the receiver operator characteristic curve were used. When compared with 358 patients not requiring target lesion revascularization, 59 patients (14%) who underwent target lesion revascularization had a lower final coronary flow velocity reserve (2.33 +/- 0.87 vs 2.48+/- 0.80, P= 0.20) and smaller final minimal lumen diameter (2.62 +/- 0.66 mm vs 2.73+/- 0.60, P= 0.19); however, those differences were not statistically significant. Patients with a coronary flow velocity reserve of < 2.0 (n=109, 26%) exhibited a significantly higher target lesion revascularization rate than patients with a coronary flow velocity reserve of > or = 2.0 (22% vs 11%, P= 0.010). This difference remained significant (odds ratio=2.01, 95% CI=1.11 to 3.66) after adjustment for other variables that were also correlated with the incidence of target lesion revascularization. Conclusion The presence of a final coronary flow velocity reserve of < 2.0 is an independent predictor of the need for target lesion revascularization after stent implantation in native coronary artery lesions.

Blood Flow Velocity↗
PubMed2001

Complications of cardiac catheterization in the current era: a single-center experience.

Consecutive cardiac catheterization procedures done over a 2-yr period (April 1996 to March 1998) were prospectively analyzed to determine and characterize procedure-related complications (in-hospital and 1-mo follow-up), as they occur at present. During the study period, 11,821 procedures (7,953 diagnostic and 3,868 therapeutic) were performed. The majority of procedures (> 60%) were done in high-risk patients. Stents were implanted in 33% of patients, and adjunctive abciximab was used in 6.6% of therapeutic procedures. The overall complication rate was 8% (3.6% of diagnostic procedures and 15.1% of therapeutic procedures). The procedure-related mortality rates were 0.2%, 0.1%, and 0.5% for total, diagnostic, and therapeutic procedures, respectively. Cardiac complications were seen in 3.9% (1.5% of diagnostic and 9% of therapeutic procedures). Emergency cardiac surgery was required in 0.05% of the diagnostic procedure group and 0.3% of the therapeutic procedure group (total, 0.1%). Despite marked changes in patient population and practice, the complication rates of cardiac catheterization remain very low.

Abciximab↗
PubMed2001

Intravascular ultrasound assessment of pulmonary vascular disease in patients with pulmonary hypertension.

BACKGROUND: Measurements of pulmonary pressure and resistance are still considered to be the "gold standard" in the evaluation of pulmonary hypertension (PH), despite their limitations in predicting irreversible disease. Hemodynamic assessment also only provides a global evaluation of the pulmonary vascular bed, whereas PH is an inhomogeneous disease of the vessel wall. METHODS AND RESULTS: We assessed the value of intravascular ultrasound (IVUS) in 30 patients with suspected PH and correlated the structural changes in distal pulmonary arteries found on IVUS with conventional hemodynamic data. Plasma endothelin (ET)-1 levels and pulmonary ET-1 extraction also were measured as markers of the severity of PH. The anatomic abnormalities revealed by IVUS were more severe in the lower lobes than in the upper lobes, as evidenced by the greater percentage of wall thickness (WT), the smaller lumen diameter/WT and lumen area/total vessel area (p < 0.05 for each). IVUS anatomic indexes correlated directly with hemodynamic data (eg, with pulmonary arterial systolic pressure; r = 0.56; p < 0.001) and ET-1 levels but inversely with pulmonary ET-1 extraction. CONCLUSION: Patients with PH have greater pulmonary arterial WT that is more severe in the lower lobes than in the upper lobes. The severity of structural abnormalities found on IVUS is directly correlated with hemodynamic findings and ET-1 levels. IVUS may provide useful additional information in the assessment of patients with PH.

Adult↗
PubMed2001

Coronary angiography using 4 or 6 French diagnostic catheters: a prospective, randomized study.

Diagnostic catheter size has been progressively decreased in order to reduce complications (particularly access-site complications) and permit early ambulation after coronary angiography. However, excessive down-sizing can result in poor catheter conformation and poor imaging quality of coronary angiograms (CA). This study randomly compared the accuracy and angiographic quality (QUAL) of CA performed with 4 French (Fr) vs. 6 Fr diagnostic catheters. Injections were done manually using a low-viscosity, non-heated, low-osmolality contrast media (Iomeprol). CAs were performed via the femoral approach using Judkins catheters. Handling, torque, selectively and stability were graded from 1 (excellent) to 4 (unacceptable) by the operator. QUAL was also graded from 1 (unacceptable) to 10 (excellent) by the operator in all patients and by an independent Core laboratory in 50 patients matched for gender and weight. Between January and April 1997, a total of 405 consecutive patients were randomized. Mean age was 63.4 +/- 11.1 years and 79% were male. Clinical characteristics of patients, quality of left coronary catheter and cross-over rates (1.5% with 6 Fr vs. 3.9% with 4 Fr catheters) were similar in both groups. Using the right coronary catheters, the only difference was handling, which was found to be easier with 6 Fr catheters (1.16 +/- 0.55 vs. 1.34 +/- 0.77, respectively; p = 0.007). Similarly, handling difficulty using the pigtail catheter was the only significant difference between the two groups (1.16 +/- 0.50 vs. 1.33 +/- 0.77, respectively; p = 0.009), but no cross-over was necessary in either group. The QUAL of CA was slightly but significantly better with 6 Fr than with 4 Fr catheters but considered non-diagnostic (< 7/10) in 1.4% vs. 6.8% of left CAs (p = NS). Procedural time (21.0 +/- 7.2 minutes vs. 19.0 +/- 8.1 minutes; p = 0.007) was shorter with 4 Fr catheters, but x-ray exposure, compression times and amount of contrast media used were similar. Ambulation was obtained at 2 hours in 15.1% vs. 34.0% of patients (p < 0.001) and at 4 hours in 43.8% vs. 52.4% (p < 0.05), respectively. The incidence of the worst access-site complication (moderate hematoma) was similar (1%) in both groups. CA can be performed using 4 Fr catheters and manual injections of low-viscosity contrast media with acceptable angiographic results in the majority of cases. This is associated with a shorter procedural time and earlier ambulation, and a decreased but acceptable angiographic quality.

Age Factors↗
PubMed2001

Treatment of long, diffuse, in-stent restenotic lesions with beta radiation using strontium 90 and sequential positioning "pullback" technique: procedural details and clinical outcomes.

BACKGROUND: Long, diffuse, in-stent restenotic lesions have been problematic for many patients, necessitating the need for multiple repeat percutaneous coronary interventions (PCI). The need for repeat PCI has been significantly reduced in patients since the advent of vascular brachytherapy. In-stent restenosis resulting in long lesions (> 30 mm) presents even more of a challenge. The interventional injury length created during PCI is usually greater than 30 mm and the vascular brachytherapy systems available in most hospitals are 30 mm or 40 mm in length. The purpose of this paper is to define "pullback technique" and to report the Montreal Heart Institute (MHI) data to show that the pullback technique using the Novoste system seems to be a safe and effective method for using vascular brachytherapy to treat long, diffuse, in-stent restenotic lesions. METHODS: We reviewed the database of patients enrolled in the Compassionate Use Registry between August 1999 and July 2000. The data are reported on 23 consecutive patients treated with the pullback technique. RESULTS: The mean lesion length was 49.4 +/- 19.8 mm. Three patients (13%) underwent target vessel revascularization. Angiographic follow-up was obtained in 18 patients (78%). Seven patients (38.8%) showed angiographic restenosis (> 50% luminal re-narrowing). No aneurysms or zones of ectasia were noted. CONCLUSION: This angiographic and clinical evaluation of the MHI Compassionate Use Registry data show the pullback technique to be safe from both a dosimetric and clinical point of view.

Beta Particles↗
PubMed2000

Randomized comparison of elective stent implantation and coronary balloon angioplasty guided by online quantitative angiography and intracoronary Doppler. DESTINI Study Group (Doppler Endpoint STenting INternational Investigation).

BACKGROUND: The purpose of this study was to compare long-term outcomes of coronary stenting in all lesions (elective stenting) or only in lesions with inadequate morphological and functional results after balloon angioplasty (guided PTCA). METHODS AND RESULTS: Treatment of multivessel disease, with any lesion length and vessel size, was allowed provided that all lesions were suitable for stent implantation. Patients were randomized to elective stent implantation (n=370) or guided PTCA (n=365). An optimal PTCA result (residual diameter stenosis </=35%, coronary flow reserve measured with a Doppler guidewire >2.0, absence of threatening dissections) was achieved in 166 lesions (43%). The remaining 218 lesions underwent stent implantation (provisional stenting). Final residual diameter stenosis was lower in the elective and provisional stent groups (9.3% and 10.2%) than in the optimal PTCA group (24.8%, P:<0. 00001). On an intention-to-treat analysis, the probability of >/=1 major adverse cardiac event at 12 months was 17.8% in the elective stenting group and 18.9% in the guided PTCA group (20.1% for optimal PTCA and 18.0% for the provisional stenting subgroup, P:=NS). The incidence of repeat target lesion revascularization at 1 year was 14. 9% in the elective stent group and 15.6% in the guided PTCA group (17.6% for optimal PTCA and 14.1% for the provisional stenting subgroup, P:=NS). CONCLUSIONS: When balloon angioplasty is guided by online quantitative angiography and Doppler-derived coronary flow reserve, with provisional stenting reserved for suboptimal results, early and late clinical outcomes are comparable to those achieved by elective stenting of all patients.

Angiography↗
PubMed2000

Influence of postangioplasty beta-irradiation on endothelial function in porcine coronary arteries.

BACKGROUND: Postangioplasty (PTCA) intracoronary radiation therapy (ICRT) has been demonstrated to limit restenosis. The consequences of these procedures on coronary reactivity are unknown. METHODS AND RESULTS: Porcine coronary arteries were studied after PTCA immediately (n=5) and 6 weeks (n=5) after ICRT (n=5 and 5, respectively), after combined PTCA+ICRT (n=5 and 7, respectively), and after no intervention (n=11). A 3-cm-long source train of Sr/Y(90) was used in vivo to deliver 16 Gy at a depth of 2 mm from the source center, as used in clinical trials. Arterial rings were mounted on myographs to record isometric tension. After achieving steady-state contraction to depolarizing physiological solution containing 40 mmol/L KCl, measured baseline tension was significantly elevated immediately after all interventions. It returned to normal levels 6 weeks after PTCA and ICRT alone but was significantly reduced if combined. Active contractions induced by 40 mmol/L KCl were maintained after combined therapy both immediately after and at 6 weeks. In these depolarizing conditions, nitric oxide-dependent relaxation to substance P was trivial after PTCA+ICRT and reduced after ICRT, whereas in the presence of physiological solution and N(omega)-nitro-L-arginine, substance P-induced relaxation was reduced after PTCA and abolished after PTCA+ICRT 6 weeks after intervention. In rings without endothelium, the relaxation mediated by sodium nitroprusside (0.1 micromol/L) was reduced immediately after PTCA and at 6 weeks. CONCLUSIONS: PTCA+ICRT altered the passive mechanical properties of porcine coronary arterial wall. Furthermore, at 6 weeks, receptor-operated release of endothelium-derived nitric oxide and endothelium-derived hyperpolarizing factor was reduced by ICRT and PTCA alone, respectively, and was prevented by their combination.

Angioplasty, Balloon, Coronary↗
PubMed2000

The effects of intracoronary brachytherapy on the natural history of postangioplasty dissections.

OBJECTIVES: The aim of this study was to determine the natural history of postangioplasty intravascular ultrasound (IVUS)-detected dissections and to assess the influence of intracoronary beta-radiation on dissection resolution. BACKGROUND: Intracoronary radiotherapy is considered to impair exaggerated vessel healing. Conversely, excessive healing impairment may increase the risk of complications due to unhealed dissection. Alternatively, residual dissection may represent an innocent marker of adequate therapy. METHODS: Immediate postangioplasty and six-month follow-up IVUS studies of 94 patients in the IVUS substudy of the MultiVitamins and Probucol (MVP) trial and 26 nonstented patients in the Beta Energy Restenosis Trial (BERT) were analyzed for the presence or absence of dissection. RESULTS: Of the 28 patients with postangioplasty dissections in MVP, only one had evidence of residual dissection at six months (95% confidence interval [CI] for failure rate 0.2%; 20.2%). Conversely, 9 of 16 dissections had healed in BERT (95% CI for failure rate 30.6%; 79.2%) (p < 0.0002). Nevertheless, an index based on dissection arc and length demonstrated improvement in the irradiated patients. Irradiated patients with residual dissections showed significant increase in lumen area at six-months (5.10 +/- 0.98 to 7.11 +/- 2.61 mm2, p < 0.02) not noted when there was resolution of the dissection (6.03 +/- 2.38 to 6.36 +/- 3.33 mm2, p = NS). In both groups the external elastic membrane area was unchanged at follow-up. CONCLUSIONS: Resolution appears to be the natural history of IVUS-detected dissections in most cases. Significant resolution of dissection occurs following intracoronary beta-radiation as reflected in reduced dissection index at six-months in these patients, although significant impairment of vessel wall healing was noted.

Aortic Dissection↗
PubMed2000

Reliability of mechanical and phased-array designs for serial intravascular ultrasound examinations--animal and clinical studies in stented and non-stented coronary arteries.

BACKGROUND: Both mechanical and multi-element intravascular ultrasound designs have potential advantages and limitations that may impact on their value for clinical and research purposes. Determination of the reproducibility of measurements is critical before a given system can be used in studies such as regression of atherosclerosis trials. METHODS: We performed serial intravascular ultrasound imaging with catheters using mechanical and phased-array designs in stented and non-stented coronary arteries in dogs and in patients. RESULTS: Both systems correlated well for areas (r > or = 0.90, p < 0.0001) and diameters (r > or = 0.84. p < 0.0001) in dogs and in patients. There was a slight difference between multi-element and mechanical designs for measurements of area (mean difference in dogs and in patients: -0.24 and 0.96 mm2, p < 0.055) and diameter (-0.08 and 0.16 mm, p < 0.0001). The reproducibility of the multi-element system for reanalysis of the same frames and for analysis of serial pullbacks was similar to the same measurements with the mechanical system (r > or = 0.96 for all measurements). The differences in absolute and relative variability between the mechanical and phased-array designs, both for reanalysis of same frames and serial pullbacks, were very small. CONCLUSIONS: Although multi-element and mechanical intravascular ultrasound designs are not strictly interchangeable, their similar reproducibility and the small differences in measurements demonstrate that both designs are acceptable alternatives for trials of regression of atherosclerosis. Determination of the variability for serial pullbacks of both designs was also important to assess the statistical power of such trials.

Animals↗