Failure or success of complex catheter-based interventional procedures assessed by intravascular ultrasound.

Intravascular ultrasound provides high resolution cross-sectional images of vessel walls and may help to characterize atherosclerotic plaque morphology subtypes. This new imaging modality may have an important role in assessing the results of standard and investigational interventional therapeutic procedures. Four case histories of patients with coronary artery disease treated with different catheter-based therapies are presented. In each case, intravascular ultrasound added diagnostic information unobtainable from standard radiographic imaging techniques. These cases, involving PTCA (balloon dilatation), directional coronary atherectomy, high-speed rotational ablation, and balloon-expandable stent implantation, each represent an interesting example of procedure success or failure that could not be fully discerned without the use of intravascular ultrasound. Specifically, the distribution of intramural dissection, the presence and magnitude of intracoronary calcification, and morphologic patterns of intimal hyperplasia leading to restenosis, were accurately identified by ultrasound images. Thus intracoronary ultrasound imaging significantly enhances the understanding of failure modes, success, and complications after therapeutic interventions in patients with complex coronary disease.     

Intravascular ultrasound parameters associated with stent thrombosis after drug-eluting stent deployment

Drug-eluting stent (DES) thrombosis (ST) can be devastating. The study aim was to evaluate intravascular ultrasound (IVUS) predictors for DES thrombosis by comparing IVUS studies after implantation in 13 patients with 14 DES thrombosis lesions with a group of controls (30 lesions in 27 patients) matched for history of chronic renal failure and type of DES. Five patients (38%) discontinued dual antiplatelet therapy at the time of ST. There were 3 in-stent restenosis lesions (21%) treated using DESs in the ST group compared with 0 in the control group (p <0.05). Compared with the control group, IVUS studies in the ST group showed a smaller minimum stent area (4.6 +/- 1.1 vs 5.6 +/- 1.7 mm(2), p = 0.0489). In the ST group, 11 of 14 stents had a minimum stent area < or =5.0 mm(2) compared with 12 of 30 in the control group (p = 0.0392). Minimum stent area in patients who stopped clopidogrel therapy and developed ST (5.30 +/- 1.15 mm(2)) tended to be larger compared with that in patients who developed ST while using clopidogrel (4.24 +/- 0.96 mm(2), p = 0.091). Within the 5-mm-long proximal and distal reference segments analyzed, the ST group had larger proximal reference maximum plaque burdens and smaller minimum lumen areas, along with a tendency toward similar findings in the distal reference segments. In conclusion, IVUS findings at the time of DES implantation in patients who subsequently developed ST showed a smaller minimum stent area (especially in patients who developed ST while using clopidogrel) and more residual disease at the stent edges.     

Angiographic and clinical outcomes of late total occlusion versus treatment failure without late total occlusion in patients after intracoronary radiation therapy for in-stent restenosis

This study aimed to compare the outcomes of patients with late total occlusion (LTO) versus patients with recurrence in the absence of LTO after intracoronary radiation therapy for in-stent restenosis. LTO, especially in the context of acute myocardial infarction, after intracoronary radiation therapy for in-stent restenosis, is associated with negative clinical outcomes after 6 and 12 months compared with in-stent restenosis without LTO.     

Three-year follow-up after intravascular gamma-radiation for in-stent restenosis in saphenous vein grafts.

The Washington Radiation for In-Stent Restenosis Trial in Saphenous Vein Grafts (SVG WRIST) demonstrated safety and efficacy of intravascular radiation therapy (IRT) for the treatment of in-stent restenosis (ISR) in SVG at 12 months. In this study, we aimed to examine whether the safety and efficacy of IRT is durable up to 36 months. One hundred twenty patients with diffuse ISR in SVG underwent balloon angioplasty, laser or atherectomy ablation, and/or additional stenting. After successful intervention, patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium (Ir)-192 (n = 60) or nonradioactive seeds (n = 60). The prescribed dose at 2 mm from the source was either 14 or 15 Gy in vessels 2.5-4.0 mm or 18 Gy in vessels > 4.0 mm in diameter. At 36 months, target lesion revascularization (TLR; 43% vs. 66%; P = 0.02) and target lesion revascularization-major adverse cardiac event (TLR-MACE; 49% vs. 71%; P = 0.02) rates continued to be lower in the IRT group, but both target vessel revascularization (TVR; 59% vs. 71%; P = 0.17) and TVR-MACE (63% vs. 77%; P = 0.11) rates were not. In SVG WRIST, patients with ISR treated with IRT had a marked reduction in the need for repeat TLR at 36 months, with sustained clinical benefit at 3 years despite late recurrences, which were more pronounced in the radiation group.     

Comparison of clinical outcomes of overlapping sirolimus- versus paclitaxel-eluting stents in patients undergoing percutaneous coronary intervention

Sirolimus-eluting stent (SES) and paclitaxel-eluting stent (PES) implantation for the treatment of single coronary lesions has proved to be effective and durable. However, the safety and efficacy of overlapping drug-eluting stents for the treatment of long lesions have not been well established. In total, 114 patients who received overlapping drug-eluting stents were identified, 55 of whom received overlapping SESs and 59 received overlapping PESs. Baseline clinical and angiographic characteristics were balanced. In-hospital complications were similar between the 2 groups. At 30-day and 6-month follow-ups, all clinical outcomes were also similar. In addition, the event-free survival rate was comparable (p = 0.71). Implantation of overlapping drug-eluting stents for the treatment of long, native coronary lesions is feasible and effective. In conclusion, in this observational study, clinical outcomes appeared similar in patients treated with overlapping SES implantation compared with those treated with overlapping PES implantation.     

Bivalirudin-associated intracoronary thrombosis during gamma-brachytherapy and its experimental validation in acute swine model.

Bivalirudin is indicated for use as an anticoagulant in patients with unstable angina undergoing percutaneous transluminal coronary angioplasty. Cases of intracoronary thrombosis have been reported with beta-radiation when bivalirudin is used as an anticoagulant. We report two cases of intracoronary thrombosis with gamma-radiation when bivalirudin is used.