Intracoronary beta-brachytherapy in chronic total occlusions: a subgroup analysis from the RENO registry

Current understanding of coronary in-stent restenosis. Pathophysiology, clinical presentation, diagnostic work-up, and management

In-stent restenosis is the limiting entity following coronary stent implantation. It is associated with significant morbidity and cost and thus represents a major clinical and economical problem. Worldwide, approximately 250 000 in-stent restenotic lesions per year have to be dealt with. The pathophysiology of instent restenosis is multifactorial and comprises inflammation, smooth muscle cell migration and proliferation and extracellular matrix formation, all mediated by distinct molecular pathways. Instent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50% regardless of the mechanical angioplasty device used. Much more favourable results were reported for the adjunctive irradiation of the in-stent restenotic lesion, with a consistent reduction of the incidence of repeat in-stent restenosis by 50%. Data from the first clinical trials on drug-eluting stents for the treatment of in-stent restenosis have shown very much promise yielding this strategy likely to become the treatment of choice. This review outlines the histological and molecular findings of the pathophysiology, the epidemiology, the predictors and the diagnostic work-up of in-stent restenosis and puts emphasis on the various treatment options for its prevention and therapy.

Predictors of 32P beta brachytherapy failure in patients with high-risk in-stent restenosis

BACKGROUND

The effectiveness of coronary radiation therapy for the treatment of in-stent restenosis (ISR) has been established in several randomized clinical trials. The efficacy of this treatment in the general population is less well established.

METHODS AND MATERIALS

We report our experience in 118 consecutive patients with nonselected high-risk ISR who had undergone successful percutaneous coronary intervention and brachytherapy with (32)P beta-irradiation and who were prospectively enrolled in a quantitative angiographic and clinical follow-up protocol at 7 months after the index procedure. The aim of this study was to investigate the independent predictor of angiographic restenosis after (32)P brachytherapy treatment.

RESULTS

Of the patients, 28.8% were diabetics. The mean lesion and mean radiated lengths were, respectively, 30.1 +/- 17.2 and 43.8 +/- 16.9 mm. The ISR pattern was diffuse in 96% of the treated lesions; in particular, 22.1% presented an occlusive pattern and 37.1% a proliferative pattern. At follow-up angiographic, restenosis and major adverse cardiac events (MACE) rates were, respectively, 20.8% and 29.6%. The univariate predictors of angiographic restenosis were procedural geographic miss, pattern IV ISR, manual pullback maneuver of the radiation source, preprocedural lesion percentage stenosis and preprocedural lesion MLD. At logistic regression analysis, only geographic miss and pattern IV ISR were independent predictors of post intracoronary radiation therapy (IRT) angiographic restenosis.

CONCLUSION

These data indicate that 7-month angiographic restenosis after (32)P IRT in complex patients with ISR is not a frequent event and is predicted mainly by an occlusive lesion at baseline and by procedural geographical miss.

Successful use of the frontrunner catheter in the treatment of in-stent coronary chronic total occlusions

Percutaneous intervention of coronary chronic total occlusion (CTO) from in-stent restenosis (ISR) is hindered by difficulty to cross the lesion with conventional guidewires. This study describes the successful treatment of five cases of CTOs from ISR using the Frontrunner controlled blunt microdissection catheter. Four of the five cases had failed previous attempts of percutaneous intervention with conventional guidewires. The Frontrunner catheter successfully facilitated the placement of guidewire into the distal true lumen in all five cases. The median crossing time was 10 min. No subintimal delivery of guidewire or vascular perforation was observed. TIMI 3 flow was achieved in all target vessels after further balloon angioplasty or stenting. The Frontrunner device is a safe and effective tool in the treatment of CTOs from ISR.