The effect of heart rate, vessel angulation and acquisition protocol on the estimation accuracy of calcified artery stenosis in dual energy cardiac CT: A phantom study.

PURPOSE: To investigate the effects of heart beat rate (bpm), vessel angulation and acquisition protocol on the estimation accuracy of calcified stenosis using a dual-energy CT scanner. METHODS: A thorax semi-anthropomorphic phantom coupled with a motion simulator and a vessel phantom representing a 50% coronary artery calcified stenosis, were used. Electrocardiograph (ECG)-synchronized acquisitions were performed at different bpms. Acquisitions were performed using A, B, and C single-energy and D dual-energy protocols. Protocol A was prospective ECG-triggered axial and protocols B and C were retrospective single- and two-segment reconstruction ECG-gated helical acquisitions. Protocol D was prospective ECG-triggered axial acquisition. The vessel phantom was placed at two angulations relative to z-axis. Images were reconstructed using all available kernels with iterative reconstruction. Stenosis-percentage was estimated using the CT vendor's vessel analysis tool. Effective dose (ED) was estimated using the dose-length product method. RESULTS: In protocols A, B, and C, measured Stenosis-percentage increased with bpm. Stenosis-percentage estimate ranged from 56.8% at 40 bpm to 62.6% at 100 bpm. In protocol D, Stenosis-percentage ranged from 59.3% at 40 bpm to 54.8% at 80 bpm. Stenosis-percentage was overestimated on respect to the nominal value in most kernels. The detail kernel exhibited the highest accuracy. Stenosis-percentage was not affected by the vessel angulation. ED for protocols A, B, C, and D was 2.4 mSv, 5.1 mSv, 5.5 mSv, and 2.8 mSv, respectively. CONCLUSIONS: Use of the dual-energy cardiac CT examination protocol along with the detail kernel is recommended for a more accurate assessment of Stenosis-percentage.

A retrospective analysis of catheter-based sources in intravascular brachytherapy.

PURPOSE: Coronary artery disease involves the deposition of plaque along the walls of a coronary artery leading to narrowed or blocked vessels (stenosis) and is one of the main causes of death in developed countries. Percutaneous transluminal coronary angioplasty (PTCA) is used to reverse stenosis. Restenosis (renarrowing) of the treated vessel is a major complication of PTCA. A metal mesh tube (stent) can be placed inside the vessel to prevent restenosis. Tissue stress incurred during PTCA and stenting can provoke neointimal cell proliferation leading to in-stent restenosis (ISR). Intravascular brachytherapy (IVBT), a form of internal radiotherapy, is used to treat ISR. Renewed interest in IVBT is being expressed as a treatment for patients with ISR in drug-eluting stents. Current treatment planning (TP) of IVBT is extremely limited and assumes human tissue can be approximated by water. The interactions of arterial plaque, guidewires, and the stent have been shown to attenuate radiation significantly but are ignored in TP. Other models have determined the degree of attenuation by each factor in isolation. For the first time, we create a model with several inhomogenities present to determine whether attenuation by multiple inhomogenities combines linearly or if a larger dose reduction than anticipated is realized. We are also able to evaluate a spatial distribution of dose around the source and in arterial walls. METHODS AND MATERIALS: A dosimetric analysis of two commercially available IVBT systems was performed in a Monte Carlo-based particle simulation (Geant4). Absorbed dose was calculated using a model of a human coronary artery with a calcified plaque and stent. Dose delivered in water was also calculated to evaluate the accuracy of a water approximation. RESULTS: Dose as a function of θ shows significant variation around IVBT sources. For the Guidant Galileo, dose is reduced by 20% behind stent struts and as much as 66% in a region occluded by the guidewire, plaque, and stent. For the Novoste Beta Cath device, delivered dose is reduced by 19% and 58%, respectively, in the same regions. CONCLUSIONS: Our findings show that the water approximation used in clinical practice to calculate dose is inaccurate when inhomogeneities are present. Methods proposed for calculating dose perturbations in IVBT may underestimate the magnitude of dose reduction. Increasing source dwell time seems unlikely to resolve dosimetric issues in IVBT. The effectiveness of currently existing ß-emitting devices may be reduced in patients with complex lesions at the treatment site. Investigation of new radioisotopes and off-centering devices should be considered to improve dose outcomes.

Long-term clinical outcomes after intravascular brachytherapy for instent restenosis and de novo coronary artery lesions in percutaneous coronary intervention.

BACKGROUND: We examined the long term clinical outcomes after administration of intravascular brachytherapy (IVBT) for instent restenosis (ISR) and de novo coronary artery lesions in percutaneous coronary intervention (PCI). METHODS AND MATERIALS: From May 2000 to August 2004, 129 symptomatic patients with ISR and de novo coronary artery lesions were treated with intravascular beta radiation after successful PCI. The primary end-point was major adverse cardiac event (MACE), i.e., a composite of all-cause death, myocardial infarction and target lesion revascularization (TLR) within 5 years of follow-up. RESULTS: The mean age of patients was 64+10 years with a male predominance (78%). The majority of patients had diffuse bare metal instent restenotic lesions and 19 patients (15%) had de novo coronary artery lesions. From hospital discharge to follow-up at 5 years (mean follow-up period 75.3+17.7 months), the annual consecutive MACE rates were 16.3%, 13.4%, 8%, 12.2% and 6.6% respectively and were mainly driven by the need for TLR. Left anterior descending artery (LAD) as target vessel of PCI was an independent predictor of long term MACE (OR: 3.5; 95% confidence interval:1.2-10.6; P=.03). There were six cases of stent thrombosis (cumulative incidence of 4.7%) with case fatality rate of 33% (2/6). CONCLUSION: MACE rates remained high post IVBT at 5 years of follow-up and were mainly driven by the need for TLR. LAD as target vessel of PCI was an independent predictor of long term MACE.

Intracoronary beta-irradiation for the treatment of de novo lesions: 5-year clinical follow-up of the BetAce randomized trial.

BACKGROUND: Vascular brachytherapy (VBT) has been used for the prevention of restenosis. Despite initial positive results, long-term follow-up has shown a progressive loss of benefit in clinical outcome after beta-irradiation. We report the 5-year follow-up of the BetAce trial. METHODS: This prospective, randomized, single-blind trial included 61 patients treated for 64 de novo coronary lesions: 31 patients (33 stenoses) were treated with bare metal stents (control group), and 30 patients (31 stenoses) were treated with intracoronary beta-irradiation at the time of stented angioplasty (VBT group). RESULTS: Baseline and procedural data were similar between treatment arms. At 6 months, VBT reduced the need for target vessel revascularization (13% vs 35.5%, P = .04), but there was no significant difference in the 6- and 12-month event-free survival when clinical events were ranked. Between 1 and 5 years, an increasing number of target vessel failures was observed in both groups, leading to a similar long-term clinical outcome at 5 years (event-free survival 43% and 45% in the VBT and control groups, respectively, log-rank 0.001, P = .9). CONCLUSIONS: Beta-irradiation in de novo coronary lesions significantly reduced in-stent recurrences at 6 months compared with standard procedures. However, this initial benefit was not sustained in the long term. The results of this randomized study confirm the delayed and progressive restenotic process after beta-irradiation and stent implantation in de novo lesions.

Long-term clinical outcome of patients treated with beta-brachytherapy in routine clinical practice.

BACKGROUND: Only limited data exist regarding the long-term efficacy of beta-brachytherapy (beta-VBT) in routine clinical practice and the impact of the prolonged (>6 months) combined antiplatelet therapy after beta-VBT. Our aim is to examine the long-term clinical efficacy of routine beta brachytherapy (beta-VBT) followed by indefinite administration of combined antiplatelet therapy in patients at high restenotic risk. METHODS: Sixty-one patients with 65 lesions [de novo: 41, in-stent restenotic (ISR): 24] underwent intracoronary beta-VBT and were followed prospectively. All patients received indefinite administration of aspirin and clopidogrel, underwent routine angiography 6 months later and were followed-up clinically for 43.7 months (range: 32 to 52 months). RESULTS: Acute success was achieved in 60/61 (98.4%) patients. Lesion length was 36.1 (+/-17.6) mm for the de novo and 22.0 (+/-9.8) mm for the ISR (p=0.001). Stents were implanted in 35/41 de novo and 7/24 ISR lesions (p<0.01). Six-month binary restenosis after successful beta-VBT was 35.9% (23/64). During follow-up patients with de-novo lesions who received a new stent during index procedure had a higher incidence of major cardiac events than patients with ISR lesions without a new stent (log rank test, p=0.02). Acute and late thrombotic events were reported at 6 patients, all with de novo lesions and stent implantation. CONCLUSIONS: Beta-VBT plus stenting in de novo lesions is related to an unacceptable high rate of thrombotic complications and clinical restenosis despite prolonged administration of combined antiplatelet therapy. Brachytherapy remains a reasonable option for patients with ISR lesions until full data from large randomized trials comparing drug eluting stents with brachytherapy are available.

Five-year clinical follow up after intracoronary radiation for the prevention of in-stent restenosis.

Intracoronary radiation therapy (IRT), utilizing both gamma- and beta-emitting radiation sources, is considered to be a safe and effective treatment for in-stent restenosis (ISR). Although no longer in clinical use, a significant number of patients were treated in the past with IRT, and their long-term outcomes have not been well documented. The aim of the present analysis was to document the long-term outcomes of all patients who underwent IRT at our institution for the prevention of recurrence of ISR. Data were collected from 132 patients (148 irradiated lesions) treated with IRT at our institution between March 1999 and January 2004. Clinical and angiographic data were collected over a 5-year period. Patients were divided into 2 groups: those with failed IRT (n = 65), defined as a procedure that resulted in a major adverse cardiac event: death, myocardial infarction, target lesion revascularization, target vessel revascularization or coronary artery bypass graft surgery at any time during the follow-up period, and patients with successful IRT (n = 67). Both groups were identical regarding baseline clinical and angiographic characteristics, with the exception of a higher percentage of multivessel disease and diffuse restenosis in patients who failed IRT (p = 0.01). At 1-year follow up, slightly less than half (43%) of those patients in the failure group experienced a major adverse cardiac event. During the long-term follow up period, half of all patients who underwent IRT at our institution experienced a major adverse cardiac event, 61 patients (46%) either died or underwent a revascularization procedure, 16 patients (24%) had a myocardial infarction or died, and 55 patients (42%) required repeat coronary revascularization. The average time to develop a major adverse cardiac event was 14.6 +/- 15 months. Therefore, during long-term follow up following IRT for the prevention of ISR, half of all patients developed a major cardiovascular event, mainly due to the need for repeat revascularization procedures.

Six years experience in intracoronary brachytherapy procedures: patient doses from fluoroscopy.

Typical patient dose levels during intracoronary brachytherapy (ICB) procedures using beta sources were determined across a sample of 221 treatments. Dose-area product values, fluoroscopy time and number of frames per procedure, with median values of 62 Gy cm2, 17.0 min and 1493 images, respectively, resulted in a 20% to 50% increase in the values measured for percutaneous transluminal coronary angioplasty procedures in the same medical centre (median values 41 Gy cm2, 14.3 min and 1078 images). Likely reasons for this increase include the additional complexity of ICB, the need for recording and reporting every step of the treatment, getting the essential parameters for the volume determination of the lesion and therapeutic radiation dose calculation and, finally, the learning curve for this kind of procedure. A high concentration skin dose distribution during ICB procedures was measured and in 12% of the patients peak skin doses higher than 1.5 Gy were confirmed. 10 patients were submitted to clinical follow-up and skin injuries were not identified.

Brachytherapy and bivalirudin evaluation study.

BACKGROUND: Bivalirudin is shown to be a competent substitute for heparin in percutaneous coronary intervention (PCI). The safety and efficacy of bivalirudin in patients undergoing PCI and vascular brachytherapy (VBT) are not known. This study aimed to assess the safety and efficacy of bivalirudin as a single antithrombotic agent in patients undergoing PCI and VBT. METHODS: A total of 152 patients enrolled in the Brachytherapy and Bivalirudin Evaluation Study underwent PCI and VBT with either gamma (n = 8) or beta radiation (n = 144). The main outcome measures were in-hospital events and 30-day clinical outcomes. All patients were treated with bivalirudin (0.75 mg/kg bolus and 1.75 mg/kg per hour infusion for beta radiation, 1 mg/kg bolus and 2.5 mg/kg per hour infusion for gamma radiation) as a single antithrombotic agent during the entire procedure. RESULTS: Baseline clinical and angiographic characteristics were similar between the 2 groups. More than 90% of the patients received beta radiation. In-hospital events showed a higher prevalence of acute procedural intracoronary thrombosis in patients treated with gamma- vs beta radiation (25% vs. 0.7%, P < .001). Thirty-day outcomes including death, Q-wave, and non-Q-wave myocardial infarctions, subacute stent thromboses, and repeat revascularizations were similar in both groups. CONCLUSION: Bivalirudin, as a single antithrombotic agent during PCI and VBT with beta emitters, may be used safely, but its use in the setting of PCI and gamma radiation may not be acceptable due to an increased incidence of acute procedural intracoronary thrombosis.

Effectiveness and determinants of the long-term beta intracoronary brachytherapy results.

BACKGROUND: Effectiveness evaluation and search for the factors determining long-term results of beta intracoronary brachytherapy (ICBT) are of a special importance in an upcoming era of drug-eluting stents usage for a wide range of clinical indications: de novo and in-stent restenosis lesions. METHODS: One hundred forty eight consecutive patients (59.6+/-9.6 years, 72% men) treated with beta ICBT for in-stent restenosis (ISR) or de novo lesions were studied. There were 135 ISR in 121 patients and 31 de novo lesions in 27 patients. Follow-up coronary angiography was performed in all patients after a mean of 8.9+/-4.5 months. Detailed qualitative and quantitative angiographic analysis of pre-, peri- and postprocedural as well as follow-up angiograms was performed. RESULTS: Forty five percent of patients treated for de novo lesions were diabetic. Thirty five percent of all targets were located in vessels with a reference vessel diameter <2.5 mm. Furthermore, 77% of ISR lesions were in Class 1 according to the Mehran classification. The mean length of an irradiated segment was 37.6 mm. The overall recurrent restenosis rate was 28.3%. Multivariate analysis revealed that the reference vessel diameter and the presence of edge injury within the proximal 32P source dose-fall off were the only independent predictors of recurrent restenosis after ICBT (OR 0.46; 95%CI 0.24-0.89; p=0.021 and OR 2.55; 95%CI 1.23-5.25; p=0.011, respectively). CONCLUSIONS: Recurrent restenosis after beta intracoronary brachytherapy treatment is negatively associated with the target vessel size. Presence of edge injury within the proximal 32P source dose-fall increases the frequency of recurrent renarrowing after ICBT. Our results indicate that target vessel size should be taken into account in optimising interventional strategy for ISR treatment: drug eluting stents versus intracoronary brachytherapy. Avoidance of edge injury within the proximal 32P source dose fall-off is strongly recommended while ICBT application.

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.

Intravascular brachytherapy: indications and management of adverse events.

Intravascular brachytherapy has become the standard of care for the treatment of coronary in-stent restenosis after repeat angioplasty. More than 5000 patients have been treated as part of various clinical trials. Based on the results of the GAMMA I trial, the START ((90)Sr Treatment of Angiographic Restenosis Trial), and the INHIBIT (INtimal Hyperplasia Inhibition with Beta In-stent restenosis Trial), the Checkmate system using (192)Ir, the Betacath system using (90)Sr/Y, and the Galileo system using (32)P, have been approved for the treatment of in-stent restenosis. With a better understanding and application of radiation oncology concepts to vascular brachytherapy, problems such as edge failure are being overcome. The complication of late thrombosis has also become less significant with the elimination of restenting at the brachytherapy procedure, and the prolonged use of antiplatelet therapy. There are other competing modalities in the early phases of clinical trials. The durability of results, lack of any significant long-term complications and the confirmation of the efficacy in other sites will further consolidate the role of radiation in treating in-stent restenosis.

Two-year clinical follow-up results of intracoronary radiation therapy with rhenium-188-diethylene triamine penta-acetic acid-filled balloon.

We investigated the 2-year clinical follow-up results as well as 6-month angiographic and clinical follow-up results of intracoronary radiation therapy using a rhenium-188-diethylene triamine penta-acetic acid ((188)Re-DTPA)-filled balloon system. The study comprised of 161 patients with significant de novo (83%) or in-stent restenosis (17%) lesions. Irradiation to deliver 17.6 Gy at a depth of 1.0 mm into the vessel wall was carried out after successful intervention. At 6-month follow-up, binary restenosis developed with significantly lower frequency in the radiation group than in the control group (24.3% vs. 46.3%; P = 0.009), although target lesion revascularization rate did not show significant benefit. At 2-year follow-up, cumulative target lesion revascularization rate was not significantly different between radiation group (n = 86) and control group (n = 75; 20.0% vs. 26.0%; P = 0.368). The rate of major adverse cardiac events including death, myocardial infarction, and target lesion revascularization did not show significant difference between two groups either (22.3% vs. 30.1%; P = 0.266). In conclusion, although significant reduction in restenosis rate was noted at 6-month angiographic follow-up, intracoronary radiation therapy mostly in patients with de novo lesion did not show significant clinical benefit in 6-month and 2-year follow-up results. The benefit was noted only in a small subgroup of patients with in-stent restenosis.

Intracoronary brachytherapy after stenting de novo lesions in diabetic patients: results of a randomized intravascular ultrasound study.

OBJECTIVES: We studied the efficacy of intracoronary brachytherapy (ICB) after successful coronary stenting in diabetic patients with de novo lesions. BACKGROUND: Intracoronary brachytherapy has proven effective in preventing recurrences in patients with in-stent restenosis. However, the role of ICB for the treatment of de novo coronary stenoses remains controversial. METHODS: Ninety-two patients were randomized to either ICB or no radiation after stenting. Primary end points were in-stent mean neointimal area (primary end point of efficacy) and minimal luminal area of the entire vessel segment (primary end point of effectiveness), as assessed by intravascular ultrasound at six-month follow-up. Quantitative coronary angiography analysis was performed at the target, injured, irradiated, and entire vessel segments. RESULTS: At follow-up, the in-stent mean neointimal area was 52% smaller in the ICB group (p < 0.0001). However, there was no difference in the minimal luminal area of the vessel segment (4.5 +/- 2.4 mm2 vs. 4.4 +/- 2.1 mm2). Restenosis rates increased progressively by the analyzed segment in the ICB group: target (7.1% vs. 20.9%, p = 0.07), injured (9.5% vs. 20.9%, p = NS), irradiated (14.3% vs. 20.9%, p = NS), and vessel segment (23.8% vs. 25.6%, p = NS). At one year, 1 cardiac death, 6 myocardial infarctions (MIs) (3 due to late stent thrombosis), and 10 target vessel revascularizations (TVRs) (6 due to the edge effect) occurred in the ICB group, whereas in the nonradiation group, there were 11 TVRs and no deaths or MIs. CONCLUSIONS: Intracoronary brachytherapy significantly inhibited in-stent neointimal hyperplasia after stenting in diabetic patients. However, clinically this was counteracted by the occurrence of the edge effect and late stent thrombosis.

Quality assurance in intracoronary brachytherapy. Recommendations for determining the planning target length to avoid geographic miss.

BACKGROUND AND PURPOSE: A new method of assessing geographic miss (GM) in endovascular brachytherapy (EVBT) is applied to evaluate the quality of intracoronary brachytherapy treatments, retrospectively. Based on the Vienna experience, recommendations for adequate safety margins are derived to avoid GM. PATIENTS AND METHODS: Evaluation is done on 136 vessels of 128 consecutive patients treated between October 1999 and July 2001. The quality of EVBT is assessed using the concept and terminology of the EVA GEC ESTRO task group. Evaluation of GM and/or safety margin is performed by comparing the outermost interventions with the reference isodose length (RIL) of the applied delivering devices on recorded compact disk (CD) angiograms. The RIL is defined as the length of the vessel segment, which receives at least 90% of the reference dose at the reference depth (=1 mm within the vessel). GM is defined as injured vessel segments, which receive a dose lower than 90% of reference dose. Measurements of intervention length (IL) and active source length (ASL) are performed with respect to anatomical landmarks within the vessel in the region of interest (e.g. stent edges), and by using the nominal length of the devices (balloons, sources) as a reference scale. The edges of RIL are determined by subtracting the length of the dose-fall-off zone (specific to the applied delivery devices: (192)Ir 4.5 mm, (90)Sr 2.5 mm, (32)P 2.0 mm) from the edges of ASL. RESULTS: The described method to assess GM is applicable to 128 vessels (94%). GM is found in 23% of proximal edges and 20% of distal edges. 95% of all GM are observed if the total margin (proximal+distal margin) between RIL and IL is shorter than 10.5 mm. CONCLUSIONS: GM in intracoronary brachytherapy can be widely avoided by adding an appropriate safety margin to the IL (5-6 mm each edge in this study) in order to determine the necessary RIL for a treatment.

Effects of beta-radiation with a 188rhenium-filled balloon catheter system on non-stented adjacent coronary artery segments.

BACKGROUND: The effects of beta-radiation with a (188)rhenium ((188)Re)-filled balloon catheter system on angiographically normal reference segments have not been well defined. METHODS: In the Seoul National University Post-Angioplasty Rhenium irradiation (SPARE) trial, patients with de novo or restenotic lesions were first treated with a conventional catheter-based technique and then randomized to either a radiation group or a control group. Irradiation was performed using a (188)Re-filled conventional balloon catheter system. Among 97 radiation group enrolled in this study from April 1998 through May 2001, 20 patients with de novo lesions who received brachytherapy with a balloon at least 10 mm longer than the length of an implanted stent, were selected and their post-intervention and follow-up intravascular ultrasound (IVUS) images were analyzed. Each reference segment was divided into two segments; full dose-irradiation with injury segment (irradiated segment; from the stent edge to the radiopaque balloon markers), and low dose-irradiation without injury segment (edge segment; 5-mm long segment proximal or distal to the location of radiopaque markers). In control group, serial IVUS analysis was available only in 10 patients, and IVUS parameters of the non-stented adjacent segments in these patients were compared to those of irradiated segments in radiation group patients. RESULTS: Forty irradiated and 38 edge segments of the 20 radiation group patients were analyzed. In proximal irradiated segments, no significant changes were found in external elastic membrane (EEM), lumen or in the plaque plus media (P&M) areas. In distal irradiated segments, significant increases in the EEM (12.5+/-4.5 to 14.0+/-5.0 mm(2), P<0.01) and P&M areas (5.5+/-2.0 to 6.6+/-2.3 mm(2), P<0.01) were found to occur without a change in lumen area. In proximal edge segments, P&M areas were significantly increased (9.0+/-1.7 to 10.5+/-2.6 mm(2), P=0.03). No significant changes in EEM, lumen or P&M areas were observed in the distal edge segments. Comparisons between the irradiated segments (n=40) in the radiation group and the non-stented adjacent segments (n=19) in the control group showed a significant difference in the percentage change of EEM areas (18.5+/-33.2% in radiation group vs. -3.1+/-32.1% in control group, P=0.02). CONCLUSIONS: beta-radiation with a (188)Re-filled conventional balloon catheter system appears to have no significant deleterious effect on angiographically normal reference segments over a 6 months follow up after brachytherapy.

Post-sirolimus-eluting stent restenosis treated with repeat percutaneous intervention: late angiographic and clinical outcomes.

BACKGROUND: We evaluated the clinical and angiographic outcomes of patients presenting with restenosis after sirolimus-eluting stent (SES) implantation treated with repeated percutaneous intervention. METHODS AND RESULTS: A total of 24 consecutive patients have undergone repeated percutaneous intervention to treat post-SES restenosis (27 lesions). The restenosis was located within the stent in 93% of lesions. From the 27 lesions, 1 (4%) was re-treated with a bare stent, 3 (11%) were treated with balloon dilatation, and the remaining 23 lesions (85%) were treated with repeated drug-eluting stent implantation (SES in 12 lesions [44%], paclitaxel-eluting stents in 11 lesions [41%]). The event-free survival rate was 70.8% after a median follow-up of 279 days from the post-SES treatment. The overall recurrent restenosis rate was 42.9%. The risk of recurrent restenosis was increased for patients with hypercholesterolemia, previous angioplasty, failed brachytherapy, post-SES restenosis needing early (<6 months) treatment, and post-SES restenosis treated with balloon dilatation. The recurrent restenosis rate of originally de novo lesions re-treated with drug-eluting stents was 18.2%. CONCLUSIONS: Even though de novo lesions treated with SES at baseline and re-treated with drug-eluting stents had reasonably better outcomes than other lesion types and strategies, our study shows that the treatment of post-SES restenosis is currently suboptimal and warrants further investigation.

Effects of gamma radiation on the noninjured and unprotected left main.

The aim of this study was to evaluate the effect of gamma radiation on the noninjured, unprotected left main coronary artery. Noninjured vessel segments are often radiated during treatment of in-stent restenosis with PCI and gamma radiation. Angiographic analysis using QCA methods was performed on 55 left main arteries of patients (32 with radiation of the left main compared to 23 controls) who participated in the Washington Radiation for In-Stent Restenosis Trials (WRIST). Baseline demographics and follow-up were comparable between the two groups, concluding that gamma radiation with long radiation safety margins is feasible and safe. Gamma radiation of noninjured irradiated left main vessels when used to facilitate wide radiation margins for proximal irradiated injured LAD and LCx is safe and does not compromise the vessel integrity and its lumen.