Paclitaxel-eluting stents for the treatment of chronic total coronary occlusions: A strategy of extensive lesion coverage with drug-eluting stents

Outcomes of Percutaneous Coronary Interventions for Long Diffuse Coronary Artery Disease with Extremely Small Diameter

BACKGROUND

The optimal percutaneous coronary intervention (PCI) strategy and clinical outcomes of long lesions with an extremely small residual lumen remain unclear. This study aimed to assess the efficacy of a modified stenting strategy for diffuse coronary artery disease (CAD) with an extremely small distal residual lumen.

METHODS

736 Patients who received PCI using second-generation drug-eluting stents (DES) ≥38 mm long were retrospectively included and categorized into an extremely small distal vessel (ESDV) group (≤2.0 mm) and a non-ESDV group (>2.0 mm) according to the maximal luminal diameter of the distal vessel (dsD_Max). A modified stenting technique was applied by landing an oversized DES in the distal segment with the largest luminal diameter and maintaining the distal stent edge partially expanded.

RESULTS

The mean dsD_Max and stent lengths were 1.7 ± 0.3 mm and 62.6 ± 18.1 mm in the ESDV group and 2.7 ± 0.5 mm and 59.1 ± 16.0 mm in non-ESDV groups, respectively. The acute procedural success rate was high in both the ESDV and non-ESDV groups (95.8% and 96.5%, p = 0.70) with rare distal dissection (0.3% and 0.5%, p = 1.00). The target vessel failure (TVF) rate was 16.3% in the ESDV group and 12.1% in the non-ESDV group at a median follow-up of 65 months without significant differences after propensity score matching.

CONCLUSIONS

PCI using contemporary DES with this modified stenting technique is effective and safe for diffuse CAD with extremely small distal vessels.

Impact of myocardial bridge on late lumen enlargement in distal reference segments after recanalization of coronary chronic total occlusion

Successful recanalization of coronary chronic total occlusion (CTO) can induce subsequent positive vascular remodeling. Although myocardial bridge (MB) is known to alter endothelial function and wall shear stress, the impact of MB on late lumen enlargement in the distal segment is unclear. A total of 59 patients who underwent successful percutaneous coronary intervention (PCI) for CTO in the left anterior descending artery (LAD) under intravascular ultrasound (IVUS) guidance and follow-up angiography at 8-12 months were included. Gray-scale IVUS images were analyzed and MB was detected. Lumen diameter (LD) at distal reference at post-PCI was quantitatively compared with corresponding LD at follow-up coronary angiography to assess late lumen enlargement. MB on IVUS was detected in 17 patients (29%). The length from LAD ostium to the entry of CTO was shorter (11.7 ± 13.9 vs. 22.8 ± 13.4 mm, p = 0.006) and LD at distal reference at post-PCI was smaller (1.65 ± 0.54 vs. 1.97 ± 0.56 mm, p = 0.049) in patients with MB than those without. At the mean follow-up of 10.4 ± 2.4 months, LD at distal reference was significantly increased by 25% from baseline to follow-up in the overall population (1.88 ± 0.57 vs. 2.21 ± 0.41 mm, p < 0.001), with a greater increase in patients with MB compared to those without (46 ± 31% vs. 17 ± 29%, p < 0.001). Multivariable analysis indicated MB as an independent predictor of late lumen enlargement. In patients with MB on IVUS, CTO was located in more proximal segment of LAD than those without. Late lumen enlargement at follow-up was greater in patients with MB compared to the counterpart.

Lumen enlargement of the coronary segments located distal to chronic total occlusions successfully treated with drug-eluting stents at follow-up

AIMS

Chronic total occlusions (CTO) are the final stage of atherosclerosis. Occluded coronary arteries have large plaque burden and negative remodelling. The aim of this study was to assess lumen and vessel changes of segments located distal to successfully recanalised CTO.

METHODS AND RESULTS

Ninety-one CTO treated with drug-eluting stents underwent quantitative coronary angiography (QCA) at baseline and at 12-18 months; 31 underwent serial intravascular ultrasound (IVUS) imaging. Angiographic changes were assessed with QCA as differences in minimal, mean and maximal lumen diameter (MinLD, MeanLD and MaxLD, respectively). Vessel changes were assessed with IVUS as changes in plaque and vessel volume. At follow-up, angiographic MinLD increased 23.9% (from 0.88±0.32 to 1.09±0.35 mm; p<0.01), MeanLD 16.4% (from 1.59±0.44 to 1.85±0.45 mm; p<0.01) and MaxLD 11.7% (from 2.39±0.67 to 2.67±0.70 mm; p<0.01). Lumen enlargement was greater in non-restenotic lesions, small lumen area at the end of the index procedure and low LDL-cholesterol levels during the study. By IVUS, lumen volume increased 26.9% (from 108.1±89.2 to 137.3±115.3 mm3; p<0.01), vessel volume increased 12.1% (from 207.1±170.2 to 232.2±196.0 mm3; p<0.01) and plaque volume tended to decrease 3.9% (from 98.9±88.7 to 94.9±89.3 mm3; p=0.07). Small lumen at baseline was related to greater lumen enlargement.

CONCLUSIONS

Segments distal to recanalised CTO showed a notable lumen and vessel enlargement with a trend toward mild plaque regression. Low LDL-cholesterol levels increase lumen enlargement.

Percutaneous Treatment of Coronary Chronic Total Occlusions Part 1: Rationale and Outcomes

Coronary chronic total occlusions (CTOs) are commonly encountered in patients with coronary artery disease. Compared to patients without coronary CTOs, those with CTO have worse clinical outcomes and lower likelihood of complete coronary revascularisation. Successful CTO percutaneous coronary intervention (PCI) can significantly improve angina and improve left ventricular function. Although currently unproven, successful CTO PCI might also reduce the risk for arrhythmic events in patients with ischaemic cardiomyopathy, provide better tolerance of future acute coronary syndrome, and possibly improve survival. Evaluation by a heart team comprised of both interventional and non-interventional cardiologists and cardiac surgeons is important for determining the optimal revascularisation strategy in patients with coronary artery disease and CTOs. Ad hoc CTO PCI is generally not recommended, so as to allow sufficient time for (a) discussion with the patient about the indications, goals, risks, and alternatives to PCI; (b) careful procedural planning; and (c) contrast and radiation exposure minimisation. Use of drug-eluting stents is recommended for CTO PCI, given the lower rates of angiographic restenosis compared to bare metal stents.

New percutaneous approaches for chronic total occlusion of coronary arteries

Successful recanalization and percutaneous revascularization of coronary arteries with chronic total occlusion (CTO) is one of the 'last frontiers' in coronary interventions. Conquering this obstacle will enable complete percutaneous revascularization in an increasing number of patients. The introduction within the last few years of enhanced guidewires combined with increasing operator experience and creative procedural techniques, such as the retrograde approach and the re-entry subintimal tracking technique (STAR), have significantly reduced the number of CTOs that should now be considered unapproachable. In addition, novel devices have been developed over recent years that may increase the success rate, as well as the safety, of the procedure. The Safe-Cross radiofrequency combines optical coherence reflectometry that warns the operator when the wire tip moves to within 1 mm of the outer vessel wall, combined with radiofrequency energy pulses to facilitate the passage. The CROSSER catheter mechanically vibrates against the face of the CTO at 20 kHz at a stroke depth of approximately 20 microm, creating a channel through the CTO. The most novel approach is the biologic one, in which proteolytic enzymes that digest the CTO cap to facilitate mechanical passage. The success rates for otherwise refractory CTOs will continue to improve with the development and validation of new imaging modalities and active energy source catheters.

Paclitaxel-coated balloon with bare-metal stenting in patients with chronic total occlusions in native coronary arteries

OBJECTIVES

We sought to evaluate the efficacy and safety of paclitaxel-coated balloon plus bare-metal stenting (BMS) in chronic total occlusions (CTOs).

BACKGROUND

Drug-eluting stent implantation after recanalization of CTOs is limited by the occurrence of restenosis and risk for late stent thromboses.

METHODS

In this prospective, bicenter trial we treated 48 patients after successful chronic total occlusion (CTO) recanalization in a native coronary artery with paclitaxel-coated balloon plus BMS. Patients were matched according to stent length, reference diameter, and diabetes mellitus with 48 patients treated with Taxus stent implantation. Dual antiplatelet therapy was prescribed for 6 months. Angiographic (clinical) follow-up was obtained after 6 (12) months. Primary endpoint was in-stent late lumen loss.

RESULTS

There was no difference in patient baseline characteristics or procedural results. Stent length was 59.7 ± 32.4 mm (16-151 mm) for paclitaxel-coated balloon plus BMS versus 56.2 ± 25.9 mm (16-132 mm) for Taxus stent. Late loss was statistically not different within the stent with 0.64 ± 0.69 mm versus 0.43 ± 0.64 mm (difference 0.20 mm, 95% confidence interval -0.07 to 0.47, P = 0.14) and at the occlusion site with 0.33 ± 0.69 mm versus 0.26 ± 0.70 mm, respectively. Restenosis rate was 27.7% compared with 20.8% (P = 0.44) and the combined clinical endpoint (cardiac death, myocardial infarction attributed to the target vessel, target lesion revascularization) was 14.6% versus 18.8% (P = 0.58), respectively.

CONCLUSIONS

In conclusion, for patients with complex CTOs in native coronary arteries the use of paclitaxel-coated balloon after bare-metal stenting was associated with similar clinical results and a nonsignificantly higher in-stent late loss compared with a matched population with paclitaxel-eluting stent implantation.

The aging patient with hemophilia

The prospects for many boys born with hemophilia today include a normal life expectancy and minimal to no joint disease. However, despite the availability of safe replacement clotting factor concentrates and effective antiviral treatment, the aging patient with hemophilia today faces many challenges. These include management of their hemophilia as well as the same age-related health issues as experienced in the general population. While increasing, data on the prevalence of comorbidities and their management in the hemophilia population remain limited. This review will focus on issues related to management of hemophilia and complications of cardiovascular, musculoskeletal, hepatic, and renal disease. Available research is summarized and potential approaches to management are discussed.

[Treatment strategies for chronic total occlusion: current status and outlook]

The present article discusses the current status of treatment strategies for chronic total occlusion (CTO) and the prospects offered by new therapies. The indication for revascularisation recognized in the current European guidelines includes the presence of typical symptoms and evidence of ischemia of over 10% of the total myocardium, while in patients with multiple vascular diseases the aim is complete revascularisation. Although the vast majority of patients with CTO fulfil these criteria, they are currently not receiving interventional treatment as frequently as expected. The reasons often given for this include the low success rates and high recurrence rates. However, both problems have been improved by drug-eluting stents (DES) on the one hand and by wire techniques and strategies on the other, such that results almost comparable with non-occluded coronary lesions can be achieved. While more advanced approaches like retrograde recanalization should be restricted to specialized centres, marked improvements can be achieved even without these special techniques by means of consistent further training and the application of modern techniques. Despite the aggressiveness of these approaches to pass through an occluded artery, the complication rate is not higher than with non-occluded lesions when the specific complications of recanalization are avoided in a careful approach. Further technical improvements are expected with the use of modern imaging techniques such as intravascular ultrasound and high-resolution CT imaging of coronary arteries.

Meta-analysis of long-term outcomes of drug-eluting stent implantations for chronic total coronary occlusions

BACKGROUND

In the treatment of chronic total occlusions (CTOs), some uncertainty exists regarding the effect of drug-eluting stents (DESs) compared with the effects of bare mental stents (BMSs). We reviewed outcomes of DES vs. BMS implantation for CTO lesions, to evaluate the risk-benefit ratio of DES implantation.

METHODS

Relevant studies of long-term clinical outcomes or angiographic outcomes of both BMS and DES implantation were examined. The primary endpoint comprised major adverse cardiovascular events (MACEs), including all-cause deaths, myocardial infarctions (MIs), and target lesion revascularizations (TLRs). A fixed-effect model and random-effect model were used to analyze the pooling results.

RESULTS

Ten studies were included according to the selection criteria. Eight were nonrandomized controlled trials, and two consisted of a randomized controlled comparison between DES and BMS implantation. No significant difference was evident for in-hospital MACE rates between the two groups (odds ratio [OR], 1.07; 95% confidence interval [CI], .53 to 2.13), but the long-term MACE rates in the DES group were significantly lower than in the BMS group (OR, .22; 95% CI, .13 to .38; P < .00001). The rates of stent restenosis and reocclusions were also significantly lower in the DES group (OR, .14; 95% CI, .09 to .20; and OR, .23; 95% CI, .12 to .41, respectively).

CONCLUSION

Implantation of the DES improves long-term angiographic and clinical outcomes compared with BMS in the treatment of CTO lesions.

Clinical and angiographic outcomes with sirolimus-eluting stents in total coronary occlusions: the ACROSS/TOSCA-4 (Approaches to Chronic Occlusions With Sirolimus-Eluting Stents/Total Occlusion Study of Coronary Arteries-4) trial

OBJECTIVES

We sought to examine angiographic and clinical outcomes with sirolimus-eluting stents (SES) in total coronary occlusion (TCO) revascularization.

BACKGROUND

Despite evaluation of drug-eluting stents beyond approved indications, few studies have evaluated their clinical benefit in TCO revascularization.

METHODS

Among 15 centers in North America, 200 consecutive TCO patients (78.8% >6 weeks TCO age) were enrolled for treatment with SES. The primary end point was 6-month angiographic binary restenosis within the treated segment.

RESULTS

Patient characteristics included: diabetes, 24.5%; prior infarction, 33.5%; and stent length, 45.9 mm median (quartile 1, 30.2 mm; quartile 2, 62.1 mm). A total of 199 patients (99.5%) were treated with SES, and procedural success was 98.0%. The 6-month binary restenosis rates were 9.5% in-stent, 12.4% in-segment, and 22.6% in-"working length" representing the entire treatment segment. Rates of 1-year target lesion revascularization, myocardial infarction, and target vessel failure were 9.8%, 1.0%, and 10.9%, respectively. Stent thrombosis occurred in 2 patients (1.0%). Using logistic regression modeling with propensity score adjustment, the absolute reduction in binary restenosis with SES compared with a historical bare-metal stent control was 37.7% (95% confidence interval [CI]: 27.2% to 48.3%, p < 0.001; odds ratio: 0.17, 95% CI: 0.09 to 0.30, p < 0.0001). Among 32 patients (16%) identified with stent fracture, target lesion revascularization was more common than patients without fracture (25.0% vs. 6.7%, p = 0.005).

CONCLUSIONS

Despite greater lesion complexity than prior TCO trials, percutaneous revascularization with SES appears safe and results in substantial reductions in angiographic restenosis and failed patency and a low rate of repeat revascularization. These findings support the use of SES in TCO revascularization. (The ACROSS/TOSCA Trial; NCT00378612).

Off-label use of drug-eluting versus bare metal stents: a lesion-specific systematic review of long-term outcomes

OBJECTIVE

The purpose of this systematic review was to evaluate differences in lesion-specific outcomes with the "off-label" use of drug-eluting stents (DES) versus bare metal stents (BMS).

METHODS

MEDLINE, PubMed, the Cochrane databases, and other Web were searched for studies evaluating off-label use of DES and BMS with the same characteristics. Of 1,258 abstracts or manuscripts reviewed, 112 studies were included (total N = 23,438). Studies were excluded if patients received both types of stent or no stent; lesion type was unknown; lesion-specific outcomes for ≥6 months were unavailable; or <25 patients were enrolled.

RESULTS

Overall mortality at 6-12 months was approximately 3% for BMS and DES for off-label use. Increase in mortality was greater from 6-12 months to 2 years with BMS than with DES (3.3%-9.1%; 2.8%-4.1%); however, rates were similar at 3 years (BMS: 18.8%; DES:15.3%). Myocardial Infarction rates were similar for both types at 6-12 months (BMS: 6.5%; DES: 6.0%). Overall rates of stent thrombosis were 1.8% and 1.7% for BMS and DES, respectively. Similar or slightly lower rates of stent thrombosis were seen for most lesion types, except higher rates for small vessels for BMS (5.2%) and true bifurcation for DES (3.3%). Rates of target lesion revascularization (TLR) were 7.5% for BMS and 19.6% for DES at 6-12 months. At 2-years TLR remained lower than DES. When the combined group was compared to registry data alone, similar values were seen.

CONCLUSIONS

Rates of mortality, myocardial infarction (MI), and stent thrombosis were similar in patients receiving BMS or DES, while TLR rates were lower in DES patients.

Retrograde techniques and the impact of operator volume on percutaneous intervention for coronary chronic total occlusions an early U.S. experience

OBJECTIVES

Our purpose was to determine if "Japanese style" technical strategies can be successfully applied in the U.S. practice environment and to better understand the learning curve for chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND

Procedural technical success remains the major limiting factor for CTO PCI, and has been unchanged over time.

METHODS

Demographic, procedural, and outcome data were collected on 636 consecutive patients between January 2005 and March 2008 having CTO PCI (514 antegrade, 122 retrograde attempts) at 2 U.S. medical centers. Operators were divided into 2 groups: higher CTO volume, retrograde operators (ROs) (>75 total CTO PCI cases and >20 retrograde attempts during the study period) and lower CTO volume, nonretrograde operators (NROs) to evaluate the impact of CTO-specific operator case volume and retrograde techniques on procedural outcomes.

RESULTS

Two operators met the criteria for RO category and 10 were NRO. ROs performed 395 CTO PCI cases (mean total CTO case experience = 197.5, 60 retrograde) and NROs performed 241 CTO PCI cases (mean total CTO case experience = 24.1, <1 retrograde) during the observed timeframe. The overall technical success was 58.9% for NROs and 75.2% for ROs (p < 0.0001). The technical success rate of NROs did not change, but the technical success for the ROs increased to 90% over time (p < 0.0001 for trend, 94.4% for retrograde and 85.7% for antegrade approaches). Observed major adverse events were similar between ROs and NROs.

CONCLUSIONS

Complex antegrade and retrograde "Japanese style" PCI approaches can be applied in the U.S. practice environment with high technical success and low adverse event rates. Higher CTO-specific operator case volume is associated with improved technical success rates.

Stent-based release of a selective PDGF-receptor blocker from the bis-indolylmethanon class inhibits restenosis in the rabbit animal model

Long-term success of modern therapies for myocardial ischemia is limited by restenosis, with proliferation and migration of vascular smooth muscle cells (VSMC) as key events. Since findings in recent years indicate, that the Platelet Derived Growth Factor (PDGF) is an important selective factor in mitogenic and motogenic pathways of VSMC, different concepts for reducing restenosis by inhibiting PDGF signaling have been investigated, with local delivery of small receptor kinase inhibitors looking most promising. We tested the stent-based delivery of the PDGF-receptor inhibitor D-65495, a bis(1H-2-indolyl)methanone, in the rabbit iliac artery model of restenosis. New Zealand white rabbits underwent balloon dilation of iliac arteries for implantation of D-65495-coated or non-coated (solvent, either DMSO or 90%THF / 10% DMSO) coronary stents. After 4 weeks stents were removed and neointima formation in medial and proximal/ distal stent sections was histomorphometrically and immunohistochemically analyzed. Arteries with D-65495 eluting stents showed an up to 50% reduced restenosis compared to control stents. Also, the neointimal area was reduced, but there were no significant differences in injury score. Importantly, endothelialization was similar for control stents as well as for D-65495-coated stents, suggesting absence of a general cytostatic effect of the inhibitor. The impact of D-65495 on PDGF-receptor signaling in the vessel wall was indirectly assessed by immunohistochemical staining for activated protein kinase Akt, and PCNA as a proliferation marker and revealed some reduction for the inhibitor-treated vessels. In conclusion, the application of D-65495 caused a significant decrease in neointima formation, further supporting the concept of using locally released PDGF-receptor kinase inhibitors as anti-restenotic agents.

Utility of drug-eluting stents in complex lesions and high-risk patients

Drug-eluting stents represent a breakthrough technology designed to deliver high concentrations of a bioactive agent locally to an atherosclerotic lesion, thereby minimizing systemic side effects of the drug. The safety and efficacy of drug-eluting stents have clearly been demonstrated in noncomplex lesions. This article presents an evidence-based analysis of the current experience with CYPHER sirolimus-eluting stents (Cordis Corp., Miami Lakes, FL) and TAXUS paclitaxel-eluting stents (Boston Scientific, Natick, MA) in a broad spectrum of high-risk and/or complex subsets of patients and lesions, including those with diabetes mellitus, multivessel disease, diffuse disease, very small vessels, lesions in saphenous vein grafts, chronic total occlusions, in-stent restenosis, ostial and bifurcation lesions, unprotected left main disease, and acute myocardial infarction. Emerging data in several of these subsets suggest that drug-eluting stents are safe and effective, and their use may currently be recommended, whereas in other groups of patients and lesions the efficacy and/or safety of drug-eluting stents remains to be determined, thus warranting caution. It is anticipated that penetration of drug-eluting stents will continue to increase, and fewer patients will require surgical revascularization to achieve sustained event-free survival.

Still a future for the bare metal stent?

Percutaneous coronary intervention has witnessed a number of instrumental breakthroughs resulting in improved clinical and angiographic outcomes. Coronary stenting has now surpassed balloon angioplasty as the main treatment strategy due primarily to a more predictable immediate success and a significantly lower risk of restenosis. Stent types have also noticeably changed over recent years with a shift from bare metal to drug eluting coatings. Despite improved outcomes with drug eluting stents however, their bare metal counterparts will continue to play a role for both clinical and economic reasons, at least for the foreseeable future.

A new understanding of chronic total occlusion from a novel PCI technique that involves a retrograde approach to the right coronary artery via a septal branch and passing of the guidewire to a guiding catheter on the other side of the lesion

Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) by the antegrade approach is sometimes difficult, especially in the right coronary artery (RCA). We performed successful PCls following a retrograde approach via a septal branch in 2 patients with CTO in RCA. The method involves leading the retrograde guidewire outside the body through an opposite guiding catheter after the wire crosses the target lesion. A balloon or stent could then be delivered retrogradely or antegradely. Even a soft retrograde wire always crosses the lesion through the true lumen, as confirmed by IVUS. Selecting a suitable collateral, a straighter rather than a larger one, is crucial. Our results do not support the current concept regarding CTOs. Probably, the distal fibrous cap is soft and the proximal one has a thin point that soft wires, even blunt ones, can penetrate easily. The distal penetration point appears to connect to the proximal uncalcified thin point. Many channels seem to spread out from the proximal side, tree-like, within the lesion. In the retrograde approach, the wire is unlikely to enter these branch channels. The results suggest that PCI by the retrograde approach may be effective for treating CTOs of RCA.

Chronic total occlusion angioplasty through supplying collaterals

Chronic total occlusions are typically difficult to recannalize especially when adverse angiographic morphologies are identified. We describe a case of chronic total occlusion crossing retrograde through the supplying collaterals followed by successful angioplasty and stenting.