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Biomedical subjects

Raoul Bonan

Publications and source records attributed to Raoul Bonan.

At least 19 recordsLinked to original sources
PubMed2007

Importance of collateral circulation in coronary heart disease.

AIMS: Collateral arteries are a common but inconsistent finding in coronary heart disease (CHD). We endeavoured to review the methods for coronary artery collateral assessment, the predictors and clinical importance of collateral blood flow, and the potential for therapeutic augmentation of collateral anastomoses. METHODS AND RESULTS: While many methods have been used to assess collateral blood flow only a few have been formally validated. Collateral flow index, as determined by measurement of intra-coronary pressure or flow velocity, is the most robust measure of collateral flow. These techniques have led to important advances in our understanding of collateral artery function. Coronary collateral arteries may prevent myocardial ischaemia in healthy subjects and in patients with CHD. A functional collateral circulation may lead to reduced ischaemia, preservation of ventricular function, and an improved prognosis. Recent trials have demonstrated that vascular progenitor cell therapies may improve ventricular function following acute myocardial infarction, raising the possibility of effective biological treatments to improve myocardial blood flow and prognosis in CHD. CONCLUSIONS: Coronary collateral anastomoses represent a prognostically important adaptive response in patients with CHD. Therapeutic augmentation of collaterals with emerging biological therapies represents a desirable goal for treating CHD patients.

Collateral Circulation↗
PubMed2007

Fatal ischemic stroke related to nonpermissive peripheral artery access for percutaneous aortic valve replacement.

This report describes an 85 year-old man who underwent percutaneous aortic valve replacement (PAVR). With a logistic euroSCORE of 37%, the patient had been refused surgical aortic valve replacement because of an unacceptably high peri-operative risk. During the PAVR procedure, severe resistance was encountered when advancing the 21 Fr delivery catheter through the left iliac artery despite pre-dilatation with a 7 mm balloon. Following this, PAVR was promptly achieved without difficulty, with excellent valve positioning, no peri-valvular leak and good hemodynamics. However, transesophageal echocardiography revealed a mobile echogenic mass within the outflow tract of the left ventricle. The mass was retrieved with a cardiac bioptome manipulated via the left femoral artery through a 9 Fr sheath. A right cerebral ischemic stroke manifested shortly after the post-procedure and the patient died on the fourth post-operative day. Post-mortem findings revealed a left subclavian artery occlusion by iliac vascular tissue. This report highlights the imperative for device-specific vascular access screening criteria and the need to minimize device size in order to safely accomplish PAVR.

Aged, 80 and over↗
PubMed2007

Implantation of the CoreValve percutaneous aortic valve.

Surgical aortic valve replacement is the only recommended treatment for significant aortic valve stenosis. Percutaneous aortic valve replacement appears to be a novel option for high-risk patients. We report the implantation of the ReValving system (CoreValve, Paris, France) in a 64-year-old woman who was refused aortic valve replacement surgery for critical aortic stenosis and left ventricular dysfunction because of severe pulmonary fibrosis. After anesthesia, the patient was put on femorofemoral cardiopulmonary bypass, and underwent a balloon valvuloplasty with subsequent retrograde aortic valve replacement by the ReValving system. Transesophageal echocardiographic monitoring of the patient's hemodynamics showed immediate improvements of the valvular area and left ventricular ejection fraction and only traces of paravalvular leaks. The patient was easily weaned from ventilation and resumed activity soon after the surgery. A multidisciplinary approach is presently necessary to offer a reliable and safe procedure.

Aortic Valve Stenosis↗
PubMed2006

Randomized, double-blind, multicenter study of the Endeavor zotarolimus-eluting phosphorylcholine-encapsulated stent for treatment of native coronary artery lesions: clinical and angiographic results of the ENDEAVOR II trial.

BACKGROUND: The use of the Endeavor stent might reduce restenosis and stent thrombosis at 9 months. METHODS AND RESULTS: Patients (n = 1197) treated for single coronary artery stenosis were enrolled in a prospective, randomized, double-blind study and randomly assigned to receive the Endeavor zotarolimus-eluting phosphorylcholine polymer-coated stent (n = 598) or the same bare metal stent but without the drug or the polymer coating (n = 599). The 2 groups were well matched in baseline characteristics. Diabetes was present in 20.1% of patients; the mean reference vessel diameter was 2.75 mm; and the mean lesion length was 14.2 mm. The primary end point of target vessel failure at 9 months was reduced from 15.1% with the bare metal stent to 7.9% with the Endeavor (P = 0.0001), and the rate of major adverse cardiac events was reduced from 14.4% with the bare metal stent to 7.3% with the Endeavor (P = 0.0001). Target lesion revascularization was 4.6% with Endeavor compared with 11.8% with the bare metal stent (P = 0.0001). The rate of stent thrombosis was 0.5% with the Endeavor, which was not significantly different from 1.2% with the bare metal stent. In 531 patients submitted to angiographic follow-up, late loss was reduced from 1.03 +/- 0.58 to 0.61 +/- 0.46 (P < 0.001) in stent and from 0.72 +/- 0.61 to 0.36 +/- 0.46 (P < 0.001) in segment. The rate of in-segment restenosis was reduced from 35.0% to 13.2% with Endeavor (P < 0.0001). There was no excessive edge stenosis, aneurysm formation, or late acquired malapposition by intravascular ultrasound imaging. Differences in clinical outcome were maintained at 12 and 24 months (P < 0.0001). CONCLUSIONS: Compared with bare metal stents, the Endeavor stent is safe and reduces the rates of clinical and angiographic restenosis at 9, 12, and 24 months.

Aged↗
PubMed2006

Predictors of recurrent in-stent restenosis after beta-radiation: An analysis from the START 40/20 trial.

OBJECTIVE: The purpose of this study was to identify potential predictors, including clinical, procedural, angiographic, and intravascular ultrasound (IVUS) parameters, for recurrent in-stent restenosis (ISR) following beta-radiation 90Strontium/Yttrium (90Sr/Y) in a large multicenter trial. BACKGROUND: Although adjunct brachytherapy reduces recurrent ISR after primary catheter-based intervention, recurrence of stenosis after brachytherapy still occurs. METHODS: We analyzed 185 IVUS cohort patients in the STent And Restenosis Therapy (START) 40/20 trial where a 40-mm, 90Sr/Y, radioactive source train was exclusively used for treatment of ISR to be treatable with a 20-mm balloon. RESULTS: Thirty-nine patients underwent target lesion revascularization. Preliminary univariate analysis showed that age, smoking, balloon/artery ratio, geographic miss, minimum lumen diameter, and diameter stenosis at baseline were associated with target lesion revascularization, while none of IVUS variables were (minimum lumen area, minimum stent area, or residual plaque burden). The multivariate logistic regression analysis showed that younger age, lower balloon/artery ratio, and presence of geographic miss were independent predictors of target lesion revascularization. CONCLUSIONS: Even with adjunct beta-radiation therapy, initial mechanical optimization, such as appropriate balloon sizing and positioning, may be critical for the prevention of recurrent ISR.

Adult↗
PubMed2006

Safety of beta radiation exposure to the non-target segment: an intravascular ultrasound dosimetric analysis.

BACKGROUND: The use of longer radioactive seed trains to avoid geographic miss may lead to greater radiation exposure to distal vasculature due to the natural tapering of coronary arteries. The aim of this study was to use IVUS-based dosimetric analysis to evaluate the effect of beta-radiation on angiographically normal, noninjured distal segments. METHODS: We analyzed 17 in-stent restenosis cases (stent length: 20 +/- 8 mm) treated with a 40 mm 90Sr/Y source train. The prescribed dose was 18.4 Gy (reference less than or equal to 3.3 mm) or 23 Gy (reference > 3.3 mm) at 2 mm from the source. Noninjured, but fully radiated, distal reference sites were determined by angiography. Based upon the three-dimensional vessel contours obtained at baseline, the minimum dose delivered to 90% of plaque volume (Dv90) was determined. Vessel, plaque and lumen volumes and Dv90 were computed in every 2 mm subsegment (n = 52). RESULTS: On average, no significant serial change was observed in plaque area (5.0 +/- 2.5 mm3/mm post-treatment to 5.6 +/- 3.1 mm3/mm at 8-month follow up; p = 0.09), vessel area (10.2 +/- 3.7 to 10.3 +/- 4.0 mm3/mm; p = 0.84), or lumen area (5.2 +/- 2.0 to 4.7 +/- 1.8 mm3/mm; p = 0.19). Subsegment analysis, however, revealed a wide range of dose distribution, with a significant positive correlation between Dv90 and plaque increase (p = 0.008), as well as vessel change (p < 0.001), representing dose-dependent positive vessel remodeling following beta radiation. Consequently, no significant relationship was observed between Dv90 and lumen change. CONCLUSIONS: Detailed IVUS-based dosimetric analysis demonstrated that beta radiation promoted positive remodeling, preventing lumen loss despite a mild increase in plaque mass on angiographically normal, noninjured distal segments.

Aged↗
PubMed2005

Two-year clinical follow-up of 90Sr/90 Y beta-radiation versus placebo control for the treatment of in-stent restenosis.

BACKGROUND: It is an ongoing concern that intracoronary brachytherapy may possibly just delay the problem of in-stent restenosis ("late catch up"). For gamma-radiation, 3 placebo-controlled studies have shown the maintenance of the initially positive effect after 2 years, but similar data do not exist for beta-radiation. STents And Restenosis Trial (START) was the first placebo-controlled randomized trial for in-stent restenosis with beta-radiation; herein, we report the 2-year clinical follow-up. METHODS AND RESULTS: Two hundred and forty-four patients were randomized to active treatment, 232 patients to placebo (nonactive source train) treatment. The primary end point of efficacy was target vessel revascularization (TVR); primary safety end point was any major adverse cardiac event (MACE) at 8 months and 2 years. Two-year clinical outcome in patients receiving brachytherapy was based on 195 of 244 original patients (79.9%) and in the placebo arm on 183 of 232 original patients (78.9%). TVR was significantly reduced by 25%; from 36.6% (placebo) to 27.5% (brachytherapy) remained significant after 2 years (RR .7 [.57-.98], 95% CI -9.2 [-17.5-0.8]). The Kaplan-Meier analysis for TVR and MACE showed improvement beginning approximately 90 days after radiation and remained almost constant for the 2 following years. Freedom from TVR was significantly increased from 62.4% +/- 3.8% to 71.6% +/- 3.3% (P = .027) and freedom from MACE from 58.9% +/- 3.7% to 68.0% +/- 3.4% (P = .035). CONCLUSIONS: The START trial shows for the first time that the initial beneficial effects of intracoronary brachytherapy with beta-radiation using 90 Sr/ 90 Y are maintained at 2-year clinical follow-up period.

Aged↗
PubMed2005

A pilot study: the Noninvasive Surface Cooling Thermoregulatory System for Mild Hypothermia Induction in Acute Myocardial Infarction (the NICAMI Study).

BACKGROUND: Hypothermia reduces metabolic demands, limits reperfusion injury, and helps salvage the injured myocardium during ST-elevation myocardial infarction (STEMI). The aim of this study was to assess early induction of noninvasive mild hypothermia in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention (PCI). METHODS: This was a safety and feasibility study of the Medivance Arctic Sun noninvasive thermoregulatory system (Medivance Inc, Louisville, Colo), used as adjunctive therapy in patients with first-time STEMI. Cooling was initiated by circulating chilled water through the Arctic Sun Energy Transfer Pads placed on the patient before primary PCI. Target temperature was 34.5 degrees C, maintained during 3 hours. Shivering was controlled with intravenous meperidine, and meperidine-related nausea was prevented with intravenous ondansetron. RESULTS: Nine patients underwent successful noninvasive surface cooling. All patients were Killip class I with a mean age of 62 years (8/9 males). Successful primary stenting was performed in all patients with glycoprotein inhibitors administered in 6 of 9 cases. Mean cooling time from induction to target temperature was 79 minutes (49 minutes in the last 4 enrolled cases). Mean total cooling duration was 267 minutes. Mean peak troponin T was 5.81 microg/L. Final TIMI flow grade 3 and final TIMI perfusion grade 3 were achieved in 9 of 9 patients and in 3 of 9 patients, respectively. Mean infarct size (by Myoview single photon emission computed tomography scans) was 23%. No hemodynamic or arrhythmic instability were documented. CONCLUSION: Mild hypothermia can be safely induced with noninvasive surface cooling in patients with STEMI undergoing primary PCI, allowing earlier myocardial protection before mechanical reperfusion therapy.

Angioplasty, Balloon, Coronary↗
PubMed2005

Differential outcome after intracoronary radiation therapy is related to a simple classification based on lesion length and reference diameter.

OBJECTIVE: We sought to develop a prognostic lesion classification based on simple angiographic parameters, lesion length and reference diameter that predicts differential outcome in patients undergoing intracoronary radiation. METHODS AND RESULTS: Three types of lesions were identified: Type A characterized by lesion length less than or equal to 30 mm, reference diameter > 2.5 mm to less than or equal to 4.0 mm (short lesion: normal diameter), Type B by lesion length less than or equal to 30 mm, reference diameter less than or equal to 2.5 mm or > 4 mm (short lesion: extreme diameter), and Type C by lesion length > 30 mm (long lesion). A total of 1,151 lesions (77.7% in-stent restenosis) in 1,098 consecutive patients undergoing brachytherapy were classified into these 3 lesion types. Overall, 79.9%, 10.3% and 9.8% patients met the criteria for Type A, B and C lesions. While the in-hospital major adverse cardiac event (MACE) rate was 1.4%, 3.6% and 3.8% (p = 0.026), the 6-month MACE rate was 16.1%, 22.5% and 32.1% (p < 0.001), the angiographic restenosis rate was 21.3%, 32.4% and 42.4% (p < 0.001), and the late thrombosis rate was 4.1%, 9.0% and 11.3%, (p < 0.001) in Type A, B and C lesions, respectively. Consequently, with increasing lesion severity, 3 risk groups with low, medium and high risk were defined. Multivariate analysis showed that Type B and C lesions were independent predictors of 6-month MACE (OR, 1.5 and 1.9, respectively). CONCLUSION: The proposed novel and easily applicable lesion classification effectively predicts early and medium term outcome, and may be used for appropriate therapeutic decision making in patients undergoing brachytherapy.

Aged↗
PubMed2004

Coronary flow velocity reserve does not correlate with TIMI frame count in patients undergoing non-emergency percutaneous coronary intervention.

OBJECTIVES: The purpose of this research was to compare the Thrombolysis In Myocardial Infarction (TIMI) frame count (CTFC) with coronary flow velocity reserve (CFVR) in patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: The relationship between CTFC and CFVR has not been adequately assessed in patients with coronary artery disease. METHODS: We studied 62 patients who underwent successful non-emergent PCI. All patients had Doppler evaluation of CFVR, CTFC, and quantitative coronary angiography. In an additional 17 patients, a frame count reserve was calculated as baseline CTFC/CTFC at peak hyperemia, induced by intracoronary adenosine after PCI. RESULTS: The CTFC decreased from 27 +/- 13 to 18 +/- 8, and CFVR increased from 1.5 +/- 0.4 to 2.6 +/- 0.7 (both p < 0.0001). The pre-PCI CTFC and the CFVR were closely related to minimal lumen diameter (p < 0.0001). After PCI, there was no correlation between CFVR and CTFC. In addition, no relationship was observed between CFVR and the frame count reserve. CONCLUSIONS: There was no significant correlation between CFVR and CTFC in patients undergoing coronary intervention. The relative utility of these measures in predicting outcomes in this setting requires further evaluation, but CTFC (or frame count reserve) does not appear to be an adequate surrogate measure of Doppler-derived CFVR.

Adenosine↗
PubMed2004

Beta-radiation for the creation of linear lesions in the canine atrium.

BACKGROUND: Creating linear lesions is important for the treatment of arrhythmias such as atrial flutter and fibrillation. Making these lesions with standard radiofrequency catheters can be difficult and may result in charring and thrombosis. The purpose of this study was to evaluate beta-radiation as a novel energy source for creating linear myocardial lesions. METHODS AND RESULTS: Eight dogs with intact conduction across the cavotricuspid isthmus were studied. The isthmus was irradiated (25 to 50 Gy) with strontium/yttrium-90 delivered via a deflectable 7F catheter (Novoste Corporation). There were no immediate effects, but bidirectional conduction block developed during follow-up studies in 7 of 8 dogs. The dog without conduction block received 25 Gy. After the animals were euthanized, histology revealed transmural, linear areas of fibrosis without any thrombus. CONCLUSIONS: Beta-radiation can safely and effectively create linear lesions that are contiguous and nonthrombogenic. This energy source may become an interesting adjunct to radiofrequency for the treatment of atrial flutter and fibrillation.

Animals↗
PubMed2004

Comparison of early and late results of a Carbofilm-coated stent versus a pure high-grade stainless steel stent (the Carbostent-Trial).

The long-term success of coronary interventions with stents is largely determined by the development of restenosis. The aim of this study was to compare a Carbofilm-coated and a pure stainless steel stent with regard to early and late adverse events. In this prospective, randomized trial, the Carbofilm-coated Carbostent and Sirius stent (same stent design, newly developed delivery system) were compared with the stainless steel stents S660, S670, and S7 (newly developed delivery system, same principal stent design with a few changes). The primary end point was relative late luminal loss, and secondary end points were diameter stenosis at 6 months, rate of restenosis, and major adverse cardiac events (MACEs) (myocardial infarction, reintervention, and death). From March 2000 to June 2002 at 18 centers in Canada and Europe, 420 patients were randomized. Relative late luminal loss (Carbofilm 28.9 +/- 23.0% vs stainless steel 26.7 +/- 20.2%, p = 0.95) as the primary end point, absolute late luminal loss (1.00 +/- 0.72 vs 0.93 +/- 0.62 mm, p = 0.95), net gain (1.32 +/- 0.82 vs 1.40 +/- 0.74 mm, p = 0.75), and the degree of stenosis (40.7 +/- 22.9% vs 38.0 +/- 20.1%, p = 0.92), as well as restenosis rates (23.5% vs 15.9%, p = 0.09) and MACEs (20.1% vs 13.7%, p = 0.11) were not significantly different. Thus, the Carbofilm coating of stents does not lead to an improvement in angiographic results or a reduction of restenosis rate and MACEs. These results agree with other trials using inactive coatings on stents, which also could not demonstrate any advantage over pure stainless steel stents.

Angioplasty, Balloon, Coronary↗
PubMed2004

Successful reduction of in-stent restenosis in long lesions using beta-radiation--subanalysis from the RENO registry.

PURPOSE: Long lesions remain a challenging task in interventional cardiology, with a high propensity of restenosis, especially within the stented segment. Although intracoronary gamma-radiation has been proved to reduce diffuse in-stent restenosis in long lesions, such an effect remains to be determined using beta-radiation. METHODS AND MATERIALS: Of 1098 consecutive patients at 46 European centers treated with localized beta-radiation ((90)Sr, Novoste Beta-Cath System), 139 patients (mean age 61.5 +/- 10.7 years, 84% male, 22% with diabetes mellitus) with lesions treated using a >40-mm source length underwent radiation using a single 60-mm source train (34%) or a stepping/pullback procedure with a 30-mm (12%) or 40-mm (87%) source length after conventional interventional procedures. The mean lesion length was 35.3 +/- 17.9 mm. RESULTS: Technical success was achieved in 96% of cases. Geographic miss was noted in 9 patients (6.5%). The reference (placebo) group was obtained from the Washington Hospital Center for In-Stent Restenosis Trial (WRIST) and the WRIST Trial for long lesions (LONG WRIST) studies by selecting the cases (94 patients) that required a dummy source length >/=13 seeds (or >51 mm in length). Statistically significant improvement was noted in late angiographic restenosis (34.7% vs. 76.5%, p <0.0001), target vessel revascularization (14.9% vs. 60.6), and major adverse cardiac events (i.e., death, myocardial infarction, or total vessel revascularization) (17.9% vs. 64.9%, p <0.0001) at 6 months in reference to the nonradiation group. CONCLUSION: This subanalysis from the Radiation in Europe with Novoste study confirms the safety and efficacy of beta-radiation combined with conventional interventional procedures in patients with diffuse, long, in-stent restenosis

Aged↗
PubMed2004

Intracoronary brachytherapy, a promising treatment option for diabetic patients: Results from a European multicenter registry (RENO).

Despite advances in the interventional treatment of coronary disease, diabetics still have double the case fatality rate as nondiabetics. The purpose of this analysis from the Radiation in Europe With Novoste (RENO) registry was to assess the clinical and angiographic 6-month outcome of diabetic patients in comparison to nondiabetic patients after localized beta-radiation. A total of 1,098 patients (83.8% with in-stent restenosis) treated with the Novoste Beta-Cath system in Europe were enrolled in the RENO registry. Diabetes was, irrespective of the type of lesion treated, no significant risk factor for major adverse cardiac events or target vessel revascularization. Individuals with diabetes (n = 256) and without diabetes (n = 833) displayed no significant differences concerning clinical or angiographic endpoints. Vascular brachytherapy appears to be the first technique to even out the increased risk of diabetic patients undergoing percutaneous coronary interventions in the routine clinical setting. Thus, intracoronary brachytherapy represents a promising treatment option for diabetic patients.

Brachytherapy↗