Intracoronary Brachytherapy: a New Technique to Prevent Restenosis After Percutaneous Coronary Interventions

Percutaneous trans luminal coronary angioplasty (PTCA) is an accepted treatment for coronary artery disease. However, angiographical restenosis is reported in 40-60% of patients after a successful PTCA. Mechanisms involved in the restenosis process are elastic recoil of the artery, local thrombus formation, vascular remodeling with shrinkage of the vessel and an overact healing process with neointimal hyperplasia. Neointimal hyperplasia develops by migration and proliferation of smooth muscle cells and myofibroblasts after balloon induced trauma of the arterial wall and by deposition of an extracellular matrix by the smooth muscle cells. The introduction of the stent in the arsenal of the interventional cardiologist has reduced the restenosis rate to 15-20%, by preventing elastic recoil and negative remodeling. However, the occurrence of restenosis after stent implantation remains unresolved, especially in small vessels and long lesions, where it may exceed 30% of the cases. It is primary caused by neointimal hyperplasia, which occurs due to trauma of the arterial wall b

Timing of Complete Revascularization Stratified by Index Presentation During On- and Off-Hours

Recent trials suggested immediate complete revascularization (ICR) as a safe alternative to staged complete revascularization (SCR), but the impact of the respective percutaneous coronary intervention strategies between on- versus off-hours is unclear. On-hours was defined as an index revascularization performed between 8:00 A.M. and 6:00 P.M., Monday to Friday, or else the procedure was defined as performed during off-hours. The primary end point consisted of a composite of all-cause mortality, myocardial infarction, unplanned ischemia-driven revascularization, and cerebrovascular events at 1-year follow-up. We used Cox regression models to relate randomized treatment with study end points. We evaluated multiplicative and additive interactions between on- versus off-hours and randomized treatment. The BIOVASC (Percutaneous Complete Revascularization Strategies Using Sirolimus Eluting Biodegradable Polymer Coated Stents in Patients Presenting With Acute Coronary Syndromes and Multivessel Disease) trial enrolled 1,097 and 428 patients during on- and off-hours, respectively. Patients randomized during off-hours were more likely to present with ST-segment elevation myocardial infarction (66.4% vs 29.5%, p &lt;0.001). The composite primary outcome occurred in 8.4% and 10.1% of patients randomized to ICR and SCR, respectively, during on-hours (hazard ratio 0.80, 95% confidence interval 0.54 to 1.19). During off-hours, the primary composite outcome occurred in 5.4% and 7.7% in ICR and SCR (0.69, 95% confidence interval 0.32 to 1.46) with no evidence of a differential effect (interaction pmultiplicative = 0.70, padditive = 0.56). No differential effect was found between treatment allocation and on- versus off-hours in any of the secondary outcomes. In conclusion, no differential treatment effect was found when comparing ICR versus SCR in patients presenting with acute coronary syndrome and multivessel disease during on- or off-hours.</p

Timing of Complete Revascularization Stratified by Index Presentation During On- and Off-Hours

Recent trials suggested immediate complete revascularization (ICR) as a safe alternative to staged complete revascularization (SCR), but the impact of the respective percutaneous coronary intervention strategies between on- versus off-hours is unclear. On-hours was defined as an index revascularization performed between 8:00 A.M. and 6:00 P.M., Monday to Friday, or else the procedure was defined as performed during off-hours. The primary end point consisted of a composite of all-cause mortality, myocardial infarction, unplanned ischemia-driven revascularization, and cerebrovascular events at 1-year follow-up. We used Cox regression models to relate randomized treatment with study end points. We evaluated multiplicative and additive interactions between on- versus off-hours and randomized treatment. The BIOVASC (Percutaneous Complete Revascularization Strategies Using Sirolimus Eluting Biodegradable Polymer Coated Stents in Patients Presenting With Acute Coronary Syndromes and Multivessel Disease) trial enrolled 1,097 and 428 patients during on- and off-hours, respectively. Patients randomized during off-hours were more likely to present with ST-segment elevation myocardial infarction (66.4% vs 29.5%, p &lt;0.001). The composite primary outcome occurred in 8.4% and 10.1% of patients randomized to ICR and SCR, respectively, during on-hours (hazard ratio 0.80, 95% confidence interval 0.54 to 1.19). During off-hours, the primary composite outcome occurred in 5.4% and 7.7% in ICR and SCR (0.69, 95% confidence interval 0.32 to 1.46) with no evidence of a differential effect (interaction pmultiplicative = 0.70, padditive = 0.56). No differential effect was found between treatment allocation and on- versus off-hours in any of the secondary outcomes. In conclusion, no differential treatment effect was found when comparing ICR versus SCR in patients presenting with acute coronary syndrome and multivessel disease during on- or off-hours.</p

Diagnosis of an Intracoronary Thrombus With Intravascular Ultrasound

A60-year-old man was referred for coronary angiography because of exertional angina (Canadian Cardiovascular Society angina classification type II). Twelve years earlier, he had had a myocardial infarction with a venous bypass graft to the right coronary artery

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

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

Geographic Miss

Background—A recognized limitation of endovascular ß-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 ß-radiation. Methods and Results—We analyzed 50 consecutive patients treated with ß-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 ß-radiation induces deleterious outcome

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