Three-year follow-up after intracoronary beta-radiation therapy for in-stent restenosis

The effect of the debulking by excimer laser coronary angioplasty on long-term outcome compared with drug-coating balloon: insights from optical frequency domain imaging analysis

This study evaluated the 1-year efficacy of excimer laser coronary angioplasty (ELCA) before drug-coated balloon (DCB) dilatation for the treatment of in-stent restenosis (ISR). Forty consecutive patients with ISR were treated by DCB with or without the use of ELCA (ELCA plus DCB, N = 20; DCB alone, N = 20). Debulking efficiency (DE) value was defined as the neointima area on optical frequency domain imaging (OFDI) debulked by ELCA. The patients in the ELCA plus DCB group were divided into two groups (greater DE (GDE), N = 10; smaller DE (SDE), N = 10) based on the median value of DE. Thereafter, the ISR segment was prepared with a scoring balloon, followed by DCB. At follow-up, binary restenosis and target lesion revascularization (TLR) were evaluated. There were no significant differences in baseline characteristics such as age, comorbidity, and ISR type. Overall, the incidence of neoatherosclerosis in the ISR segment was 17.5%. Post-PCI, acute gain of minimum lumen diameter on quantitative coronary angiography and of minimum lumen area on OFDI was numerically higher in the GDE than in the SDE and the DCB alone group. At follow-up, the occurrences of binary restenosis and TLR in the ELCA plus DCB group were 20.0% and 10.0%; these values in the DCB alone group were 20.0% and 20.0%, respectively. Two patients from the SDE and none from the GDE developed TLR. DCB alone treatment was inferior to ELCA plus DCB treatment. However, greater ELCA debulking might be required to obtain optimal outcomes.

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 β-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.

Paclitaxel-coated balloon catheter versus paclitaxel-coated stent for the treatment of coronary in-stent restenosis: the three-year results of the PEPCAD II ISR study

AIMS

Treatment of bare metal in-stent restenosis with the paclitaxel-coated balloon catheter based on the PACCOCATH® technology has yielded superior six-month angiographic and one-year clinical results compared to a paclitaxel-eluting stent. The three-year clinical follow-up is presented.

METHODS AND RESULTS

One hundred and thirty-one patients with coronary bare metal in-stent restenosis (>70%, length: <22 mm, vessel diameter: 2.5-3.5 mm) were randomly treated with the paclitaxel-coated balloon (DCB) (3 µg/mm²) or a paclitaxel-eluting stent (DES). Clinical follow-up information was requested from the patients and from their physicians. Quantitative angiographic and demographic baseline data were statistically not different between the groups. Per intention-to-treat analysis at 12 months, the lesion-related rates of major adverse cardiac events were 7.6% and 16.9% (p=0.11) while at 36 months the respective numbers were 9.1% and 18.5% (p=0.14). These differences were primarily due to reduced target lesion revascularisation (TLR) in DCB 4/66 (6.2%) compared to DES patients 10/65 (15.4%) (p=0.10). From 12 to 36 months, 1/65 (1.5%) DCB patients experienced a myocardial infarction while neither TLR nor death occurred in any study patient in either group during that period.

CONCLUSIONS

The six-month superiority of the paclitaxel-coated balloon compared to the paclitaxel-eluting stent in the treatment of bare metal coronary in-stent restenosis persisted throughout the three-year clinical follow-up period indicating stability of the lesions treated. (ClinicalTrials.gov Identifier: NCT00393315).

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.