Angiographic and clinical outcome of a new self-expanding intracoronary stent (RADIUS): results from multicenter experience in Japan

Coronary stents: looking forward

Despite all the benefits of drug-eluting stents (DES), concerns have been raised over their long-term safety, with particular reference to stent thrombosis. In an effort to address these concerns, newer stents have been developed that include: DES with biodegradable polymers, DES that are polymer free, stents with novel coatings, and completely biodegradable stents. Many of these stents are currently undergoing pre-clinical and clinical trials; however, early results seem promising. This paper reviews the current status of this new technology, together with other new coronary devices such as bifurcation stents and drug-eluting balloons, as efforts continue to design the ideal coronary stent.

Effect of statin on restenosis after radius stent implantation in patients with acute coronary syndrome

Despite reports that statin treatment reduces the rate of coronary restenosis with a balloon expandable stent, there is no evidence that statins affect the incidence of restenosis with a self-expanding Radius stent. Ninety-five patients with acute coronary syndrome who had been implanted with a Radius stent were classified into two groups: those with hyperlipidemia and initial statin treatment (statin group, n = 38) and those without statin treatment (comparative group, n = 57). At six months after stent implantation, the rate of coronary restenosis was significantly lower in the statin group (10.5%) than control group (28.1%) (p = 0.033), while there were no differences in morphology, maximal inflation pressure or stent size between the two groups. Interestingly, there was no difference in the serum lipid profile between the two groups at the 6-month follow-up, although the statin group had a significantly lower rate of restenosis. In conclusion, initial statin therapy reduced the rate of coronary restenosis even when a Radius stent was implanted.

Early and midterm patency of the proximal anastomoses of saphenous vein grafts made with a Symmetry Aortic Connector System

OBJECTIVE

The purpose of this study was to investigate (1) the early and midterm patency rates in saphenous vein grafts that were anastomosed with the Symmetry Aortic Connector System (St Jude Medical, Inc, St Paul, Minn) and (2) risk factors for graft occlusion.

METHODS

Thirty-one patients underwent off-pump coronary artery bypass grafting for proximal saphenous vein graft anastomoses with the aortic connector system. Intraoperative graft flow was studied with transit time flowmetry, and angiography was performed before discharge in 29 cases. Midterm (at least 1 year after the operation) saphenous vein graft patency was assessed by coronary angiography or 3-dimensional coronary computed tomography in 27 cases.

RESULTS

Postoperative angiography demonstrated a 100% patency rate and no significant stenosis at the connector-anastomosed sites. The 1-year patency rate of the saphenous vein grafts with the aortic connector system was 92.6%, with 2 cases of saphenous vein graft occlusion. Both of these cases had low graft flow and poor left ventricular function documented during the operation.

CONCLUSION

Once surgical errors had been ruled out, the 1-year patency rate of proximal saphenous vein grafts anastomosed with the aortic connector system was favorable. Poor left ventricular function and low graft flow during the operation were risk factors for midterm graft occlusion. Selection of the target vessel and its runoff may also be an important determinant of long-term patency.

Self-expanding coronary stent (Radius) implantation with cutting balloon angioplasty

To evaluate the effect of cutting balloon (CB) angioplasty on the outcome of self-expanding coronary stent implantation, we compared the results of Radius stent implantation using two predilation strategies. Seventy de novo lesions in 70 patients (60 men) were included in the study. Stenting was performed after conventional angioplasty (n = 38, group 1) or CB angioplasty (n = 32, group 2). In-stent restenosis (ISR) rates of each group were 39 and 10% at 6-month follow-up (p = 0.02). Major adverse cardiac events occurred in 20 and 11%, respectively (p = 0.25). Multivariate analysis revealed that ISR was predicted only by lesion length > or = 20 mm. In conclusion, CB angioplasty did not reduce ISR after Radius stent implantation, when other independent risk factors, such as lesion length, were taken into consideration.

Acute and Long-Term Outcomes of Rotational Atherectomy in Small (<3.0 mm) Coronary Arteries

Conventional balloon angioplasty (BA) of small coronary arteries (SCA) is followed by a high rate of restenosis. Rotational atherectomy may be effective as an alternate treatment of stenoses unsuitable for other devices. The purpose of this study was to assess the efficacy of RA in the treatment of SCA. A retrospective analysis was performed of 226 lesions in 159 consecutive patients who underwent RA of SCA (mean diameter = 2.36 +/- 0.49 mm). One hundred forty-eight lesions (65.5%) were type B2 or C of AHA/ACC criteria. Follow-up angiography was performed at 3 and 6 months after the procedure. Procedural success was achieved in 96.9% of patients. The mean burr-to-artery ratio was 0.74 +/- 0.17. Adjunctive BA and stent implantation were needed in 94.2% and 22.6% of lesions, respectively. Minimal lumen diameter (MLD) increased from 0.66 +/- 0.35 mm to 1.97 +/- 0.58 mm (P < 0.01). Angiographic complications consisted of acute reclosure (3.5%), no reflow/slow flow (12.4%), and coronary artery perforation (1.8%). No death, Q-wave myocardial infarction (MI), or coronary artery bypass graft (CABG) occurred during the initial hospitalization. Restenosis rates at 3 and 6 months were 40.6% and 44.2%, respectively, and target lesion revascularization (TLR) rates were 28.5% and 33.0%, respectively. Restenosis and TLR rates during follow-up were comparable among patients who underwent RA + adjunctive BA versus patients who underwent RA + stenting. Long-term clinical follow-up was complete in 143 patients over a mean period of 348 +/- 166 days. The survival free from cardiac death, MI, CABG or repeated BA was 59.6% at 1 year. In conclusion, RA of SCA has relatively high restenosis rates, but may be appropriate for more complex, calcified lesions unsuitable for other devices.

Nitinol versus stainless steel stents: acute thrombogenicity study in an ex vivo porcine model

Acute and subacute stents thrombosis along with thrombus mediating neointimal proliferation within the stent struts remain major concerns in coronary stenting. Up to date, there is an obvious lack of data on the thrombogenicity of stent materials in physiological conditions. This study was performed to compare the relative thrombogenicity of nitinol versus stainless steel stents. Nitinol stents were laser cut to reproduce the exact geometry of the stainless steel Palmaz stents and tested in an ex vivo AV shunt porcine model under controlled conditions. Nitinol stents presented only small amounts of white and/or red thrombus principally located at the strut intersections while Palmaz stents clearly exhibited more thrombus. As a result, 125I-fibrin(ogen) adsorption and (111)I-platelets adhesion were significantly lower on nitinol than on stainless steel devices (36%, p = 0.03 for fibrin(ogen) and 63%, p = 0.01 for platelet). These results were confirmed by scanning electron observations showing different thrombus morphologies for nitinol and stainless steel. Along with the unique mechanical properties of nitinol, its promising haemocompatibility demonstrated in our study may promote their increasing use for both peripheral and coronary revascularization procedures.

Comparison of the self-expanding Radius stent and the balloon-expandable Multilink stent for elective treatment of coronary stenoses: a serial analysis by intravascular ultrasound

We compared the outcome of the self-expanding Radius stent and the balloon-expandable Multilink stent serially by angiography and intravascular ultrasound. Successful stent deployment was achieved in 66 lesions of 56 stable angina patients (34 lesions with Radius stents and 32 lesions with Multilink stents). At follow-up, there were no significant differences in minimal lumen diameter or percent diameter stenosis between the groups, nor in restenosis rates, although the Radius stent group rate was slightly lower (23.5% vs. 31.3%). In the Radius stent group, stent cross-sectional area (CSA) increased gradually after implantation until the 6-month follow-up (8.37 +/- 1.83 to 10.16 +/- 2.59 mm(2); n = 15), giving a larger CSA (P = 0.03) than the Multilink stent group, which decreased (9.00 +/- 2.05 to 8.27 +/- 2.15 mm(2); n = 17). The lumen CSA was also slightly larger (6.82 +/- 3.06 vs. 5.84 +/- 1.85 mm(2); P = 0.29) in the Radius stent group. These findings indicated that the Radius stent enlarged progressively after implantation, which might be useful for prevention of restenosis.