Intracoronary beta-radiation therapy inhibits recurrence of in-stent restenosis.

BACKGROUND: Intracoronary gamma-radiation therapy reduces recurrent in-stent restenosis (ISR). This study, BETA WRIST (Washington Radiation for In-Stent restenosis Trial) was designed to examine the efficacy and safety of the beta-emitter 90-yttrium for the prevention of recurrent ISR. METHODS AND RESULTS: A total of 50 consecutive patients with ISR in native coronaries underwent percutaneous transluminal coronary angioplasty, laser angioplasty, rotational atherectomy, and/or stent implantation. Afterward, a segmented balloon catheter was positioned and automatically loaded with a 90-yttrium, 0.014-inch source wire that was 29 mm in length to deliver a dose of 20.6 Gy at 1.0 mm from the balloon surface. In 17 patients, manual stepping of the radiation catheter was necessary for lesions >25 mm in length. The radiation was delivered successfully to all patients, with a mean dwell time of 3.0+/-0.4 minutes. Fractionation of the dose due to ischemia was required in 11 patients. At 6 months, the binary angiographic restenosis rate was 22%, the target lesion revascularization rate was 26%, and the target vessel revascularization rate was 34%; all rates were significantly lower than those of the placebo group of gamma-WRIST. CONCLUSIONS: beta-Radiation with a 90-yttrium source used as adjunct therapy for patients with ISR results in a lower-than-expected rate of angiographic and clinical restenosis.

Prolonged antiplatelet therapy to prevent late thrombosis after intracoronary gamma-radiation in patients with in-stent restenosis: Washington Radiation for In-Stent Restenosis Trial plus 6 months of clopidogrel (WRIST PLUS).

BACKGROUND: Intracoronary gamma-radiation reduces recurrent in-stent restenosis. Late thrombosis (>30 days after radiation therapy) is identified as a serious complication. The Washington Radiation for In-Stent Restenosis Trial (WRIST) PLUS, which involved 6 months of treatment with clopidogrel and aspirin, was designed to examine the efficacy and safety of prolonged antiplatelet therapy for the prevention of late thrombosis. METHODS AND RESULTS: A total of 120 consecutive patients with diffuse in-stent restenosis in native coronary arteries and vein grafts with lesions <80 mm underwent percutaneous coronary transluminal angioplasty, laser ablation, and/or rotational atherectomy. Additional stents were placed in 34 patients (28.3%). After the intervention, a closed-end lumen catheter was introduced into the artery, a ribbon with different trains of radioactive (192)Ir seeds was positioned to cover the treated site, and a dose of 14 Gy to 2 mm was prescribed. Patients were discharged with clopidogrel and aspirin for 6 months and followed angiographically and clinically. All patients but one tolerated the clopidogrel. The late occlusion and thrombosis rates were compared with the gamma-radiation-treated (n=125) and the placebo patients (n=126) from the WRIST and LONG WRIST studies (which involved only 1 month of antiplatelet therapy). At 6 months, the group receiving prolonged antiplatelet therapy had total occlusion and late thrombosis rates of 5.8% and 2.5%, respectively; these rates were lower than those in the active gamma-radiation group and similar to those in the placebo historical control group. CONCLUSIONS: Six months of clopidogrel and aspirin and a reduction in re-stenting for patients with in-stent restenosis treated with gamma-radiation is well tolerated and associated with a reduction in the late thrombosis rate compared with a similar cohort treated with only 1 month of clopidogrel and aspirin.

The effect of intracoronary radiation for the treatment of recurrent in-stent restenosis in patients with chronic renal failure.

OBJECTIVES: This study was designed to analyze the in-hospital and six-month clinical and angiographic outcomes of patients with chronic renal failure (CRF) treated with intracoronary radiation for the prevention of recurrence of in-stent restenosis. BACKGROUND: Patients with CRF are at a higher risk than the general population for accelerated atherosclerotic cardiovascular disease and for restenosis after percutaneous coronary intervention. Previous studies have shown the effectiveness of both beta and gamma radiation in preventing recurrent restenosis in patients with in-stent restenosis. METHODS: We studied the in-hospital and six-month clinical and angiographic outcomes of 118 patients with CRF and 481 consecutive patients without CRF who were treated with intracoronary radiation for the prevention of recurrence of in-stent restenosis in native coronaries and saphenous vein grafts. RESULTS: Patients with CRF were usually older, women, hypertensive and diabetic, with multivessel disease and with reduced left ventricular function. In-hospital outcome for patients with CRF was marred by a higher incidence of death, non-Q-wave myocardial infarction and major vascular and bleeding complications. At six-month follow-up, the mortality rate was higher in patients with CRF, 7.6% compared with 1.9% in non-CRF patients (p = 0.003). Restenosis, target lesion revascularization (TLR) and target vessel revascularization (TVR) rates were similar in the two groups. In patients with CRF, radiation therapy compared to placebo reduced restenosis (53.8% vs. 22.6%, p = 0.04), TLR (71.4% vs. 15.3%, p < 0.0001) and TVR (78.6% vs. 23.7%, p = 0.0002). CONCLUSIONS: Intracoronary radiation for the prevention of recurrence of in-stent restenosis achieved similar rates of restenosis and revascularization procedures in patients with and without CRF. Despite this benefit, patients with renal dysfunction continued to have significantly higher in-hospital and six-month adverse outcomes.

Transient alterations of the QRS complex and ST segment during percutaneous transluminal balloon angioplasty of the left anterior descending coronary artery.

Using continuous 3-lead electrocardiographic (ECG) recordings in 19 patients undergoing elective percutaneous transluminal coronary artery angioplasty (PTCA) of the left anterior descending (LAD) artery, this study described the dynamic changes of the ST segment and the R- and S-wave amplitudes that occur during transient myocardial ischemia. The waveforms from lead V2 were quantified at 10-second intervals during the length of the balloon inflation that produced the greatest extent of ST-segment deviation. The simultaneous changes that occurred in leads aVF and V5 were also observed, but not quantified. Measurements of R- and S-wave amplitudes were performed during maximal ischemia from both the PR- and the J-ST-segment baselines to determine which of these most nearly maintained its control position during ischemia. The results indicate that the R-wave amplitude is best determined from the PR-segment baseline (p = 0.0007), while the S wave is best determined from the J-ST-segment baseline (p = 0.03). However, only a portion of the QRS changes observed during PTCA could be accounted for by the baseline shift. There were additional QRS changes during ischemia in 11 of the patients (58%) suggestive of conduction disturbances in 3 endocardial sites: left septal, right septal and left anterosuperior. It is hypothesized that these changes may represent ischemia-induced delay in conduction ("periischemic block") previously thought to occur only with myocardial infarction.