Intravascular ultrasonic predictors of angiographic restenosis after long coronary stenting

Coronary stents and vascular response to implantation: literature review

Drug-eluting stents (DESs) have minimized the limitations of bare-metal stents (BMSs) after percutaneous coronary interventions. Nevertheless, serious concerns remain about possible late complications of stenting, such as stent thrombosis (ST) and in-stent restenosis (ISR), although the introduction of second-generation DESs seems to have softened the phenomenon, compared to the first-generation ones. ST is a potentially catastrophic event, which has been markedly reduced by optimization of stent implantation, novel stent designs, and dual antiplatelet therapy. The exact mechanism to explain its occurrence is under investigation, and, realistically, multiple factors are responsible. ISR of BMSs has been previously considered as a stable condition with an early peak (at 6 months) of intimal hyperplasia, followed by a regression period beyond 1 year. On the contrary, both clinical and histologic studies of DESs have demonstrated evidence of continuous neointimal growth during long-term follow-up, named "late catch-up" phenomenon. The acknowledgment that ISR is a relatively benign clinical condition has been recently challenged by evidences which reported that patients with ISR can experience acute coronary syndromes. Intracoronary imaging is an invasive technology that allows identifying features of atherosclerotic plaque of stent implanted and of vascular healing after stenting; it is often used to complete diagnostic coronary angiography and to drive interventional procedures. Intracoronary optical coherence tomography is currently considered a state-of-the-art imaging technique; it provides, compared to intravascular ultrasound, better resolution (at least >10 times), allowing the detailed characterization of the superficial structure of the vessel wall. Imaging studies "in vivo," in agreement with histological findings, suggest that chronic inflammation and/or endothelial dysfunction may induce late de novo "neoatherosclerosis" inside both BMSs and DESs. So, neoatherosclerosis has become the prime suspect in the pathogenesis of late stent failure.

Stent placement for treatment of long-segment (≥40 mm) carotid atherosclerotic stenosis: results and long-term follow-up in a single-center experience

BACKGROUND

Treatment of long segment carotid stenosis (≥40 mm) with carotid artery stenting (CAS) has rarely been reported. In randomized trials, use of longer stents (>40 mm) has been associated with adverse clinical events. Here, we report our preliminary experience on the stent length and outcome in treating long segment carotid arterial stenosis.

METHODS AND RESULTS

Between August 2003 and February 2013, 22 patients with long segment stenosis of the carotid artery were treated by CAS. The mean stent length was 58.5 mm (50-60 mm). The procedures were successful in all patients, and all reported remarkable relief of symptoms immediately after stent placement. Complications included 1 case of cerebral hemorrhage and one death from myocardial infarction at 10 months. The mean follow up was 27.3 months (10-60 months). One follow-up was lost. 2 patients had late stent thrombosis at 22 and 36 months by CTA follow-up. 18 patients had persistent relief, and angiography/CTA showed normal carotid flow.

CONCLUSIONS

Our study showed that stenting for long carotid stenosis (≥40 mm) can be beneficial. Large scale clinical trial is needed to further evaluate its efficacy and safety.

Assessment of efficacy and safety of combining "paclitaxel" eluting balloon and "limus" eluting stent in the same lesion

OBJECTIVES

To assess the safety and efficacy of combining drug-eluting balloon (DEB) and drug-eluting stents (DES) in the same coronary lesion.

BACKGROUND

Use of DEB may not always produce optimal results or even result in dissection, compelling the operators to consider bailout stenting with bare metal stents (BMS). However, BMS may not be ideal in patients who have significant risk-profile for restenosis. We have opted for DES over BMS in such situations and present our follow-up data.

METHODS

Between 2009 and 2011, 46 patients (57 lesions) requiring bailout stenting following DEB use were treated with second-generation DES. All patients had at-least one or more risk-factors that made them vulnerable for restenosis (diabetes, chronic kidney disease, previous in-stent restenosis [ISR], and/or long diffuse lesions ≥ 30 mm).

RESULTS

Of the 57 lesions, 34 (60%) were previous ISR. The mean length of the DEB was: 36.2 ± 5.6 mm. All patients had TIMI-3 flow post PCI with no in-lab complications. At median follow-up of 12.3 months (interquartile range [IQR]: 7.5-18.1), the rates target lesion revascularization (TLR) and target vessel revascularization (TVR) were 3 (5.3%) and 4 (7%), respectively. One patient had died 3 months following treatment. There were no episodes of myocardial infarction, definite or probable stent thrombosis. The major adverse cardiovascular events (MACE) rate defined as cardiac-death, MI, and TVR occurred in 11% of patients.

CONCLUSION

The results from this novel strategy of combining "Paclitaxel" eluting balloon and "Limus" eluting stent in a same lesion are encouraging. Dual drug-elution acting on two different pathways may provide potential synergy that may explain the favorable outcome.

Stent placement for treatment of long segment (≥80 mm) carotid artery stenosis in patients with Takayasu disease

PURPOSE

To evaluate the effectiveness and safety of carotid artery stent (CAS) placement for treatment of long segment stenosis in patients with Takayasu arteritis.

MATERIALS AND METHODS

Between January 2002 and February 2012, all patients with Takayasu arteritis found to have long segment (≥80 mm) carotid artery stenoses at a single institution were retrospectively analyzed. Five patients treated by CAS placement with either long or multiple self-expandable stents were included. All patients had focal neurologic symptoms, including three strokes and two transient ischemic attacks (TIAs). Six self-expanding stents were used in five patients. The mean follow-up period was 19.2 months (range, 6-30 mo); all patients had clinical evaluation, laboratory examination, and vascular imaging follow-up.

RESULTS

Improvement in clinical symptoms was shown after successful angioplasty. There were no perioperative or in-hospital deaths. Four patients exhibited persistent relief, and repeated angiography or computed tomography (CT) angiography showed normal flow. One patient stopped taking her medications after CAS placement and became symptomatic 8 months later as a result of a severe in-stent stenosis.

CONCLUSIONS

CAS placement was shown to be a feasible option for treating long segment (≥80 mm) stenosis of carotid arteries in patients with Takayasu arteritis with encouraging results.

Effect of oversized partial postdilatation on coatings of contemporary durable polymer-based drug-eluting stents: a scanning electron microscopy study

BACKGROUND

 Oversized postdilation of drug-eluting stents (DES) is often performed to avoid stent malapposition. In stents implanted in long lesion or major bifurcations, extremely oversized partial postdilation may be required, which exposes DES coating to extreme forces. This study aims to assess shape and incidence of coating irregularities on durable polymer-based DES following extremely oversized partial postdilatation.

METHODS

 Fifteen DES samples (3 3.5 mm stents of Cypher Select plus [Cordis Europa, Roden, the Netherlands], Taxus Liberté[Boston Scientific Corp., Natick, MA, USA], Endeavor Sprint [Medtronic Vascular, Santa Rosa, CA, USA], Endeavor Resolute [Medtronic Vascular, Santa Rosa, CA, USA], and Xience V [Abbott Vascular, Santa Clara, CA, USA]) were deployed in sterile water (37 °C) at 14 atm, followed by a proximal postdilation with noncompliant 5.0-mm balloons at 18 atm. Stents were then examined with scanning electron microscopy.

RESULTS

 Thorough examination of a total of 660 scanning electron microscopic images demonstrated that shape and incidence of coating irregularities in the postdilated and/or transitional DES regions differed only mildly from the nonpostdilated regions. Cypher Select plus showed more peeling without bare metal aspect in the postdilated and transitional regions, and cracks were wider (P < 0.001) in the postdilated and transitional regions; in Taxus Liberté one additional irregularity (torn webbing) and more wrinkles were observed (P < 0.05 for both); in Endeavor Resolute wider cracks were found in the extremely postdilated region only (P < 0.001). Endeavor Sprint and Xience V showed no differences in shape or incidence of coating irregularities between oversized and nonoversized stent regions.

CONCLUSIONS

 Bench side assessment of five contemporary durable polymer-based DES with scanning electron microscopy suggests that even very aggressive stent postdilatation results in no more than mild differences in coating irregularities between postdilated and nonpostdilated stent regions. 

In-stent restenosis

The introduction of coronary stents marked a major turning point in the practice of interventional cardiology. Whereas the efficacy of balloon angioplasty was challenged both by immediate mechanical complications and by a high incidence of restenosis, coronary stents offered cardiologists a means by which to not only augment immediate procedural success, but also to reduce the incidence of restenosis following coronary intervention. However, despite technological advances and an improved understanding of the restenotic process, the overall rate of in-stent restenosis following bare metal stent implantation remains high. Although the introduction of drug-eluting stents has further reduced the incidence of restenosis, the "real-world" application of drug-eluting stents in increasingly complex lesion and patient subsets has given way to the even greater clinical challenge of managing drug-eluting stent restenosis. Although the standard treatment of bare metal stent restenosis typically involves placement of a drug-eluting stent, the optimal therapeutic approach to drug-eluting stent restenosis remains less defined. The issue of in-stent restenosis (especially following implantation of a drug-eluting stent) remains a clinical challenge, and investigation into therapeutic options remains ongoing. As technology evolves, such investigation will likely incorporate novel approaches including drug-coated balloons novel stent designs.

Distinguishing characteristics of erythrocyte-rich and platelet-rich thrombus by intravascular ultrasound catheter system

BACKGROUND

Acute coronary syndromes are associated with platelet-rich, white thrombi (WT) and erythrocyte-rich, red thrombi (RT), but their ultrasonic characteristics are not well defined. To determine whether intravascular ultrasound (IVUS) could be used to detect specific characteristics of WT and RT, two experiments were performed.

METHODS

An in-vitro experiment evaluated five WT and five RT and an ex-vivo experiment evaluated thrombi from 17 atherosclerotic rabbits with disrupted plaques and overlying thrombi. Specimen were mounted flat, immersed in a saline bath and examined from the intimal surface. Thrombi were classified as WT (n = 69) or RT (n = 40) by gross inspection and histology. IVUS was performed using a 1 mm, 20 MHz transducer in a 4.8F catheter. Images were digitally converted and points integrated to account for angular and depth resolution. Sampling was performed at the water-tissue interface and four other sites at 0.3 mm radial depth increments. Signals from each depth were standardized by obtaining the ratio of each energy level to the level at the water-tissue interface.

RESULTS

The average energy ratio backscattered by RT was constant with increasing tissue depth while it attenuated for WT (P < 0.005; 2-way ANOVA). RT was less homogeneous and had more backscatter compared to WT. Light and electron microscopy corroborated these observations showing WT as densely homogenous and RT with loose cellular elements.

CONCLUSION

WT may be detected by its attenuated ultrasound pattern versus a non-attenuated pattern for RT by IVUS. This technique has potential for characterizing WT and RT.

Intravascular ultrasound assessment of drug-eluting stent expansion

BACKGROUND

In the drug-eluting stent (DES) era, stent expansion remains an important predictor of restenosis and subacute thrombosis. Compliance charts are developed to predict final minimum stent diameter (MSD) and area (MSA). The objectives of the study were (1) to assess DES expansion by comparing intravascular ultrasound (IVUS)-measured MSD and MSA against the values predicted by compliance charts and (2) to compare each DES against its bare-metal stent (BMS) equivalent.

METHODS

We enrolled 200 patients with de novo coronary lesions treated with single, >2.5-mm Cypher (Cordis, Johnson & Johnson, Miami Lakes, FL) (sirolimus-eluting stent [SES], 133 patients) or Taxus (Boston Scientific, Natick, MA) (paclitaxel-eluting stent [PES], 67 patients) stent under IVUS guidance without another postdilation balloon. We used a comparison cohort of 65 equivalent BMS (Express 2 [Boston Scientific], 37 patients; Bx Velocity [Cordis, Johnson & Johnson], 28 patients) deployed under similar conditions.

RESULTS

The DES achieved only 75% +/- 10% of predicted MSD and 66% +/- 17% of predicted MSA; this was similar for SES and PES. Furthermore, 24% of SES and 28% of PES did not achieve a final MSA of 5 mm(2), a consistent predictor of DES failure. The SES achieved 75% +/- 10% of predicted MSA versus 75% +/- 9% for Bx Velocity (P = .9). The PES achieved 79.9% +/- 14% of predicted MSA versus 79% +/- 10% for Express 2 (P = .8). Lesion morphology, arc and length of calcium, stent diameter and length, and implantation pressures did not affect expansion.

CONCLUSIONS

Compliance charts fail to predict final MSD and MSA. A considerable percentage of DES does not achieve minimum standards of stent expansion. The SES and PES achieve similar expansion to their BMS platform, indicating that the polymer coating does not affect DES expansion in vivo. However, stent expansion cannot be predicted from preintervention IVUS lesion assessment.

Initial and Long-Term Outcomes of Sirolimus-Eluting Stents for Calcified Lesions Compared With Bare-Metal Stents

The aim of this study was to compare the initial and long-term outcomes of sirolimus-eluting stents (SES) and bare-metal stents (BMS) in patients with calcified lesions without performing rotational atherectomy. The subjects were 79 consecutive lesions (38 in the SES group and 41 in the BMS group) which were confirmed to have superficially calcified lesions by intravascular ultrasound. In all lesions, the stent was implanted after predilatation with a balloon. The patient characteristics were not different between the 2 groups. All procedures were successfully performed in both groups. Vessel area was significantly smaller in the SES group than in the BMS group (11.01 +/- 3.88 mm(2) versus 13.08 +/- 3.49 mm(2), P < 0.005), as was the lumen area (5.41 +/- 2.31mm(2) versus 6.48 +/- 2.04 mm(2), P < 0.005). Minimum stent area was significantly smaller in the SES group than in the BMS group (5.61 +/- 1.54 mm(2) versus 6.69 +/- 1.74 mm(2), P < 0.01). In cases in whom angiographic follow-ups were performed, the late loss was significantly smaller in the SES group than in the BMS group (0.19 +/- 0.49 mm versus 0.76 +/- 0.48 mm, P < 0.001). The restenosis rate was significantly lower in the SES group than in the BMS group (8.8% versus 33.3%, P < 0.05) and the TLR rate tended to be lower in the SES group (7.9% versus 19.5%). Stent thrombosis was not observed in either group. The results suggest that SES are more effective than BMS and can be used safely when treating calcified lesions if predilatation with a balloon is possible.

Clinical and angiographic follow-up after long versus short stenting in unselected chronic coronary occlusions

BACKGROUND

Few data are available on the efficacy of long stenting for lesions in unselected chronic total occlusion (CTO).

HYPOTHESIS

The study was undertaken to evaluate the angiographic restenosis and long-term clinical outcomes after long stent implantation in patients with CTO.

METHODS

Our retrospective analysis includes a consecutive series of stent implantation in 220 patients with CTO. We compared angiographic restenosis, target lesion revascularization, and long-term clinical outcomes of short stenting (< 20 mm, Group 1, n = 113) with a concurrent series of long stenting (> or = 20 mm, Group 2, n = 107).

RESULTS

Angiographic follow-up was obtained in 174 patients (79.5% of those eligible), and the rates of angiographic restenosis were 19.3% in Group 1 and 33.7% in Group 2 (p < 0.05). In multivariate analysis, the postinterventional minimal lumen diameter was the only independent predictor of restenosis (odds ratio = 0.20, 95% confidence interval 0.08-0.49, p < 0.01). The angiographic restenosis rate was significantly lower in Group 1 than in Group 2 in patients with final minimal lumen diameter < 3.0 mm (28.9 vs. 55.9%, respectively, p < 0.05). However, the angiographic restenosis rate was not significantly different between the two groups in patients with final minimal lumen diameter > or = 3 mm (12.0 vs. 19.2%, respectively, p = NS). During the follow-up (29.1 +/- 10.8 months), there was no difference between the two groups in death, nonfatal myocardial infarction, and target lesion revascularization.

CONCLUSIONS

The use of long (> or = 20 mm) versus short (< 20 mm) stents in patients with CTO is associated with a higher angiographic restenosis rate, but there is an equivalent risk of restenosis in selected patients with relatively large-sized vessels.

Comparison of sirolimus-eluting stent, paclitaxel-eluting stent, and bare metal stent in the treatment of long coronary lesions

OBJECTIVE

This study compared the efficacy of the sirolimus-eluting stent (SES), the paclitaxel-eluting stent (PES), and the bare metal stent (BMS) for long coronary lesions.

BACKGROUND

The outcome of drug-eluting stent (DES) implantation in long coronary lesions remains unclear.

METHODS

The study involved 527 patients with de novo long coronary lesions (> or = 24 mm), which were treated with long (> or = 28 mm) SESs (223 lesions), PESs (194 lesions), or BMSs (201 lesions).

RESULTS

Lesions in the SES (36.0 +/- 14.9 mm, P < 0.001) and PES (36.3 +/- 14.5 mm, P < 0.001) groups were longer than those in the BMS group (32.0 +/- 12.3 mm), meaning the two DES groups had longer stented segments than did the BMS group. Six-month angiographic follow-up showed the SES (9.3%, P < 0.001) and PES (21.3%, P < 0.001) groups had lower in-segment restenosis rates than that of the BMS group (42.5%). The rate of major adverse cardiac events (MACE) including death, myocardial infarction, and target lesion revascularization at 9 months was higher in the BMS group (26.6%) than that in the SES (13.0%, P < 0.001) and PES (15.7%, P < 0.001) groups. Posthoc analysis of the two DES groups showed that the in-segment restenosis rate was lower for the SES than that for the PES group (P = 0.002), while the MACE rate was similar.

CONCLUSIONS

The use of DESs for long coronary lesions appears to be safe and more effective than the use of BMSs in terms of restenosis and adverse clinical events. SES use was associated with lower late luminal loss and a lower angiographic restenosis rate compared with PES use.

Intravascular ultrasonic assessment of stent diameters derived from manufacturer's compliance charts

We used intravascular ultrasound (IVUS) to assess the accuracy of manufacturers' stent balloon compliance charts. Many interventional cardiologists rely on manufacturers' compliance charts to select stent size and optimize stent diameters according to inflation pressures during percutaneous procedures. We randomly selected 212 patients who had de novo coronary lesions that had been treated with a single, bare metal, > or =3.0-mm stent (Bx velocity, NIR, TETRA/PENTA, S660/S670/S7) under IVUS guidance. Cases of stent overlap and postdilatation with another balloon were excluded. Predicted stent diameters were derived from each manufacturer's compliance charts, and stent size and final maximal deployment pressures were derived from each physician's report. IVUS-measured minimum stent diameters (range 1.4 to 4.0 mm, mean 2.79 +/- 0.48) were smaller than predicted diameters (range 3.1 to 4.57 mm, mean 3.79 +/- 0.44). The ratio of IVUS to predicted diameters ranged from 44% to 97% (mean 74 +/- 10%). This finding was common to all 3 stent sizes: 74 +/- 12% for 3.0 mm, 73 +/- 9% for 3.5 mm, and 74 +/- 9% for 4.0-mm stents (p = 0.9). This finding was also common to all 4 stent manufacturers, 72 +/- 8% for Boston Scientific, 76 +/- 11% for Guidant, 73 +/- 9% for Cordis, and 74 +/- 11% for Medtronic (p = 0.13), and to different stent lengths. Only 3.8% of the stents achieved 90% of the predicted minimum stent diameters, and only 24.6% achieved 80% of the predicted minimum stent diameters. In conclusion, in human coronary arteries, minimal stent diameter measured by IVUS is significantly smaller than that predicted by in vitro compliance charts. These differences are independent of stent manufacturer, length, diameter, and deployment pressure.

New approaches to long lesions

Long coronary lesions, comprising up to 20% of the interventional practice, pose a significant challenge to the interventionalist. Several approaches have been described to treat long coronary lesions with long-term suboptimal outcomes. Atherectomy and laser treatments with or without adjunctive balloon angioplasty have not been shown to be superior to conventional balloon angioplasty alone. Preliminary data with the use of drug-eluting stents in the treatment of long coronary lesions appears to be promising even in small vessels and may eventually become the mainstay treatment of long lesions.

Angiographic restenosis following intravascular beta-brachytherapy does not correlate with delivered dose: a study with dose volume histograms. Recurrence of in-stent restenosis after brachytherapy

INTRODUCTION

Vascular brachytherapy reduces recurrence after treatment of in-stent restenosis. However, there are still failures. The aims of the study were to investigate the relationship between two distinct dose prescriptions and the calculated dose delivered versus binary angiographic restenosis.

METHODS AND MATERIALS

Fifty-five lesions in 47 patients underwent catheter-based beta-brachytherapy with a (32)P source. Doses delivered were calculated using intravascular ultrasound (IVUS) measurements. Patients randomly received 20 Gy either at 1 mm beyond mean reference lumen or 1 mm beyond mean reference external elastic membrane. Using subsequent off-line volumetric IVUS measurements, dose volume histograms (DVHs) for the adventitia were determined.

RESULTS

There were 13 restenotic lesions including four total occlusions. All recurrences localized within stented segment. The frequency of restenosis was similar between dosimetry groups (20% vs. 28%; P=.5). DVH calculations were similar in restenotic versus restenosis-free lesions. However, postprocedural IVUS minimal lumen area was significantly smaller for lesions that recurred (5.03+/-1.19 mm(2) vs. 6.13+/-1.7 mm(2); P=.042).

CONCLUSIONS

Calculated cumulative doses delivered to the tissues do not correlate with clinical outcome. However, an adequate lumen may be important to accommodate even a small amount of recurrent intimal hyperplasia to limit restenosis and need for target lesion revascularization.

Overlapping vs. one long stenting in long coronary lesions

Intervention of long coronary lesions remains problematic, and optimal treatment strategy is yet to be determined. Despite advancement of stent technology, data are few regarding the efficacy of overlapping stents vs. a single long stent in long coronary lesions. This study was performed to evaluate the results of those strategies for long coronary lesions and to determine the predictors of in-stent restenosis (ISR). Sixty-four lesions (> 20 mm) in 64 patients were treated with either one long stent (group 1, n = 32) or two overlapping stents (group 2, n = 32). Overlapping stents were used at tortuous or calcified lesions and at lesions with diameter discrepancy or significant dissection. Immediate results, follow-up clinical and angiographic outcomes, and predictors of ISR were evaluated. Procedures were successful in all patients in both groups. Clinical and angiographic follow-ups were performed in 54 (84%) cases and 50 (78%) cases, respectively. During the follow-up, major adverse cardiac event occurred in 36% of group 1 and 29% of group 2 (P = 0.56). Six-month ISR rates were 39% in group 1 and 41% in group 2 (P = 0.91). Age (>/= 65 years old) was an independent risk factor of ISR (54% vs. 23%; OR = 4.4; P = 0.04), and distal reference diameter (RD) of less than 2.5 mm tended to predict ISR in multivariate analysis (60% vs. 25%; OR = 3.5; P = 0.06). In conclusion, stent overlapping can be used with outcome similar to that of one long stent in long coronary lesions. The optimal result may be obtained by considering the patient's age and the distal vessel diameter of the lesion.

Conflicting functional assessment of stenoses in patients with previous myocardial infarction

The utility of fractional flow reserve, absolute and relative flow reserve, and intravascular ultrasound may have an impact on decision-making for percutaneous coronary intervention in patients with previous myocardial infarction and microvascular dysfunction. The role for fractional flow reserve, absolute and relative flow reserve, and intravascular ultrasound is discussed.

Influence of stent treatment strategies in the long-term outcome of patients with long diffuse coronary lesions

Diffuse coronary lesions (length > 20 mm) are still considered high risk for percutaneous intervention even in the current stent era. We compared the 2-year outcome of patients with long diffuse stenosis treated by three different stent strategies. In addition, we also analyzed the possible factors influencing a favorable late outcome. Our series is constituted by 232 patients with 247 long lesions treated between May 1994 and April 1999; 82 patients received one single long stent (group 1), 71 patients were treated by overlapped multiple stents (group 2), and 79 with multiple nonoverlapped stents (group 3). The mean age was 59 +/- 11 years. There were not significant differences between groups in terms of age, risk factors, clinical presentation, type of lesion, or adjunctive medical therapy. Patients from group 1 had shorter lesions (29 +/- 10 mm) than patients from groups 2 (41 +/- 15 mm) and 3 (36 +/- 14; P < 0.05). Major cardiac events (death, acute myocardial infarction, or repeat revascularization) at 24 +/- 12 months follow-up took place in 39 patients (17%). The probabilities of being free of major events at follow-up were 71%, 78%, and 80% for group 1, 2, and 3 respectively (P = NS). Only three variables were identified as significant predictors of these late events: smaller vessel size, smaller minimal lumen diameter after stenting, and the type of lesion being restenotic as compared with native stenosis. Patients with diffuse lesions treated by single long stents did not have a better late outcome than those who received multiple stents. The best late outcome was observed in those patients who had bigger vessel size, larger poststent lumen dimensions and native lesions, regardless of the stent deployment strategy used.

Intravascular ultrasound guidance improves angiographic and clinical outcome of stent implantation for long coronary artery stenoses: final results of a randomized comparison with angiographic guidance (TULIP Study)

BACKGROUND

Long coronary lesions treated with stents have a poor outcome. This study compared the 6-month outcome of stent implantation for long lesions in patients randomized to intravascular ultrasound (IVUS; n=73) or angiographic guidance (n=71).

METHODS AND RESULTS

Stenoses >20 mm in length and a reference diameter that permitted a stent diameter > or =3 mm were eligible. Primary end points were 6-month minimal lumen diameter (MLD) and the combined end point of death, myocardial infarction, and target-lesion revascularization (TLR). Baseline clinical and angiographic data were comparable in both groups. At 6 months, MLD in the IVUS group (1.82+/-0.53 mm) was larger than in the angiography group (1.51+/-0.71 mm; P=0.042). TLR and combined end-point rates at 6 months were 4% (n=3) and 6% (n=4) in the IVUS group and 14% (n=10) and 20% (n=14) in the angiography group, respectively (P=0.037 for TLR and P=0.01 for combined events). Restenosis (>50% diameter stenosis) was found in 23% of the IVUS group and 45% of the angiography group (P=0.008). At 12 months, TLR and the combined end point occurred in 10% (n=7) and 12% (n=9) of the IVUS group and 23% (n=17) and 27% (n=19) of the angiography group (P=0.018 and P=0.026), respectively.

CONCLUSIONS

Angiographic and clinical outcome up to 12 months after long stent placement guided by IVUS is superior to guidance by angiography.

Impact of various intravascular ultrasound criteria for stent optimization on the six-month angiographic restenosis

We evaluated the impact of different intravascular ultrasound (IVUS) criteria on 6-month angiographic restenosis in 511 patients with 560 lesions. Seven IVUS criteria were evaluated in this study; stent area at lesion segment 1) > or = 100% of distal reference lumen area, 2) > or = 90% of distal reference lumen area, 3) > or = 80% of average reference lumen area, 4) > or = 90% of average reference lumen area, 5) > or = 55% of average reference vessel area, 6) >/= 7 mm(2), and 7) > or = 2). Using the relative measurement (criteria 1-5), the angiographic restenosis rate was not statistically different. However, absolute measurement of stent area > or = 9 mm(2) (criteria 6 and 7) were associated with significantly lower restenosis rate (14.8% vs. 30.9%, P = 0.001, and 13.5% vs. 24.6%, P = 0.006, respectively). In conclusions, using the relative measurement of IVUS criteria, the occurrence of angiographic restenosis might not be predicted. The absolute measurement of IVUS stent area was the predictor of angiographic restenosis.

Relation between residual plaque burden after stenting and six-month angiographic restenosis

The degree of residual plaque burden outside of a stent might be correlated with the degree of intimal hyperplasia. However, the relation between residual plaque burden and angiographic restenosis are still unknown in a large number of patients. Therefore, we evaluated the effect of residual plaque burden after stenting on 6-month angiographic restenosis. Intravascular ultrasound (IVUS)-guided coronary stenting was successfully performed in 723 patients with 785 native coronary lesions. Six-month follow-up angiograms and evaluation of residual plaque burden by IVUS were available in 566 patients (78.3%) with 622 lesions (79.2%). Results were evaluated using conventional methods. The overall angiographic restenosis rate was 23.0% (143 of 622 lesions). There was no significant difference in residual plaque burden between the lesions with and without restenosis (52% vs 51%, respectively, p = 0.148). The angiographic restenosis rate was 20.8% (11 of 53 lesions), 21.6% (51 of 236 lesions), 22.0% (55 of 250 lesions), and 31.3% (26 of 83 lesions) in the lesions with residual plaque burden < 40%, between 40% and 50%, between 50% and 60%, and > 60%, respectively (p = 0.284). Using multivariate logistic regression analysis, the only independent predictor of angiographic restenosis was the IVUS stent area (odds ratio 0.807, 95% confidence intervals 0.69 to 0.95, p = 0.011). Furthermore, even in the lesions with residual plaque burden > 60%, the restenosis rate was 37.3% (23 of 61 lesions) versus 13.6% (3 of 22 lesions ) in IVUS stent areas of < 7 and > or =7 mm(2), respectively (p = 0.031). In conclusion, residual plaque burden outside the stent might not predict angiographic restenosis. IVUS stent area was the only independent predictor of angiographic restenosis.

A randomized comparison of the value of additional stenting after optimal balloon angioplasty for long coronary lesions: final results of the additional value of NIR stents for treatment of long coronary lesions (ADVANCE) study

OBJECTIVES

We sought to investigate the clinical benefit of additional stent implantation after achieving an optimal result of balloon angioplasty (BA) in long coronary lesions (>20 mm).

BACKGROUND

Long coronary lesions are associated with increased early complications and late restenosis after BA. Stenting improves the early outcome, but stent restenosis is also related to both lesion length and stent length.

METHODS

A total of 437 patients with a single native lesion 20 to 50 mm in length were included and underwent BA, using long balloons matched to lesion length and vessel diameter (balloon/artery ratio 1.1) to achieve a diameter stenosis (DS) <30% by on-line quantitative coronary angiography (QCA). "Bail-out stenting" was performed for flow-limiting dissections or >50% DS. Patients in whom an optimal BA result was achieved were randomized to additional stenting (using NIR stents) or no stenting. The primary end point was freedom from major adverse cardiac events (MACE) at nine months, and core laboratory QCA was performed on serial angiograms.

RESULTS

Bailout stenting was necessary in 149 patients (34%) and was associated with a significantly increased risk of peri-procedural infarction (p < 0.02). Among the 288 randomized patients, the mean lesion length was 27+/-9 mm, and the vessel diameter was 2.78+/-0.52 mm. The procedural success rate was 90% for the 143 patients assigned to BA alone (control group), as compared with 93% in the 145 patients assigned to additional stenting (stent group), which resulted in a superior early minimal lumen diameter (0.54 mm, p < 0.001) and led to reduced angiographic restenosis (27% vs. 42%, p = 0.022). Freedom from MACE at nine months was 77% in both groups.

CONCLUSIONS

A strategy of provisional stenting for long coronary lesions led to bailout stenting in one-third of patients, with a threefold increase in peri-procedural infarction. Additional stenting yielded a lower angiographic restenosis rate, but no reduction in MACE at nine months.

Palmaz stent deployment for subclavian and brachiocephalic arterial occlusive disease. Factors predictive of restenosis

SUMMARY

Palmaz stent deployment is a useful method for subclavian and brachiocephalic arterial occlusive disease. We evaluated restenosis or intimal thickening after Palmaz stent deployment for nine lesions of subclavian or brachiocephalic arterial occlusive disease focusing on stent diameter, atheroma thickness near the stent, and degree of coverage for the lesion. Follow up DSA and IVUS at 5-14 months (mean 9) after therapy showed no significant changes in the size or shape of the stent itself There were two lesions of thin in-stent intimal hyperplasia and five lesions of thick hyperplasia. There was no close relationship between intimal hyperplasia and stent diameter or atheroma size (relative thickness). There was some relationship between the degree of coverage of the lesion by the stent and degree of intimal hyperplasia, but to determine statistical significance, accumulation of a greater number of cases is necessary.

Six-month angiographic follow-up after intravascular ultrasound-guided stenting of infarct-related artery: comparison with non-infarct-related artery

BACKGROUND

Compared with balloon angioplasty, stenting has been established as an effective treatment modality to reduce restenosis in patients with acute myocardial infarction. However, the immediate results that predict favorable long-term outcomes in the acute infarct stenting are unknown. Therefore, we evaluated long-term outcomes of stenting for infarct-related artery (IRA) lesions by using intravascular ultrasound (IVUS) compared with that of stenting for non-IRA lesions.

METHODS

IVUS-guided coronary stenting was successfully performed in 510 native coronary lesions (105 IRA vs 405 non-IRA). A 6-month follow-up angiogram was performed in 419 (82.2%) lesions: 87 (82.9%) IRA lesions and 332 (82.0%) non-IRA lesions. Coronary stenting on the IRA lesions was successfully performed within 7 to 10 days after onset of infarction in 42 patients and within 12 hours in 45 patients. Results were evaluated by clinical, angiographic, and IVUS methods.

RESULTS

There were no significant differences in clinical and angiographic variables between the two groups. IVUS variables including reference vessel area and minimal stent area were also similar between the two groups. There was no significant difference in angiographic restenosis rate between the two groups in cases of minimal stent area > or = 7 mm(2): 12.8% (6 of 47) in IRA versus 19.1% (33 of 173) in non-IRA lesions (P = .315). However, the angiographic restenosis rate in cases of minimal stent area <7 mm(2) was 50% (20 of 40) in IRA lesions versus 31.5% (50 of 159) in non-IRA lesions (P = .028).

CONCLUSIONS

Angiographic restenosis is significantly higher in stenting for IRA lesions compared with that for non-IRA lesions in cases of minimal stent area < 7 mm(2).

Long-term outcomes of minor dissection at the edge of stents detected with intravascular ultrasound

We evaluated the influences of minor edge dissections on late angiographic in-stent restenosis in 327 patients with 348 lesions (281 lesions without edge dissection and 67 lesions [19.3%] with edge dissection); the angiographic restenosis rate was 29.9% in the lesions with edge dissections versus 25.3% without edge dissections (p = 0.540). The minor non-flow-limiting dissections at the edge of stents may not be associated with the development of late angiographic in-stent restenosis.

Long-term outcomes of minor plaque prolapsed within stents documented with intravascular ultrasound

The direct relationship between minor plaque prolapsed within stents and late in-stent restenosis is unknown. Therefore, we evaluated the impact of minor plaque prolapse on late angiographic in-stent restenosis. Intravascular ultrasonography (IVUS)-guided single-coronary stenting was successfully performed on 384 consecutive patients with 407 native coronary lesions. Six-month follow-up angiographic evaluation was performed on 315 patients (82. 0%) with 334 lesions (82.1%). Minor plaque prolapsed within the stent was found in 75 of 334 lesions (22.5%). Results were evaluated using angiographic and IVUS methods. The development of minor plaque prolapse was significantly associated with infarct-related artery (P = 0.000) and small pre-intervention minimal lumen diameter (P = 0. 001). The overall angiographic restenosis rate was 23.1% (77/334)-21.3% (16/75) in the lesions with plaque prolapse vs. 23.6% (61/259) in the lesions without plaque prolapse (P = 0.806). In conclusion, minor plaque prolapsed within stents might not be associated with late angiographic in-stent restenosis.