Influence of balloon pressure during stent placement in native coronary arteries on early and late angiographic and clinical outcome: A randomized evaluation of high-pressure inflation

Efficacy of intravascular lithotripsy (IVL) in coronary stenosis with severe calcification: A multicenter systematic review and meta-analysis

BACKGROUND

With heavily calcified coronary and peripheral artery lesions, lesion preparation is crucial before stent placement to avoid underexpansion, associated with stent thrombosis or restenosis and patency failure in the long-term. Intravascular lithotripsy (IVL) technology disrupts superficial and deep calcium by using localized pulsative sonic pressure waves, making it to a promising tool for patients with severe calcification in coronary bed.

AIMS

The aim of the study is to systematically review and summarize available data regarding the safety and efficacy of IVL for lesion preparation in severely calcified coronary arteries before stenting.

METHODS

This study was conducted according to the PRISMA guidelines. We systematically searched PubMed, SCOPUS, and Cochrane databases from their inception to February 23, 2023, for studies assessing the characteristics and outcomes of patients undergoing IVL before stent implantation. The diameter of the vessel lumen before and after IVL, as well as stent implantation, were analyzed. The occurrence of major adverse cardiovascular events (MACE) was assessed using a random-effects model.

RESULTS

This meta-analysis comprised 38 studies including 2977 patients with heavily calcified coronary lesions. The mean age was 72.2 ± 9.1 years, with an overall IVL clinical success of 93% (95% confidence interval [CI]: 91%-95%, I2 = 0%) and procedural success rate of 97% (95% CI: 95%-98%, I2 = 73.7%), while the in-hospital and 30-days incidence of MACE, myocardial infarction (MI), and death were 8% (95% CI: 6%-11%, I2 = 84.5%), 5% (95% CI: 2%-8%, I2 = 85.6%), and 2% (95% CI: 1%-3%, I2 = 69.3%), respectively. There was a significant increase in the vessel diameter (standardized mean difference [SMD]: 2.47, 95% CI: 1.77-3.17, I2 = 96%) and a decrease in diameter stenosis (SMD: -3.44, 95% CI: -4.36 to -2.52, I2 = 97.5%) immediately after IVL application, while it was observed further reduction in diameter stenosis (SMD: -6.57, 95% CI: -7.43 to -5.72, I2 = 95.8%) and increase in the vessel diameter (SMD: 4.37, 95% CI: 3.63-5.12, I2 = 96.7%) and the calculated lumen area (SMD: 3.23, 95% CI: 2.10-4.37, I2 = 98%), after stent implantation. The mean acute luminal gain following IVL and stent implantation was estimated to be 1.27 ± 0.6 and 1.94 ± 1.1 mm, respectively. Periprocedural complications were rare, with just a few cases of perforations, dissection, or no-reflow phenomena recorded.

CONCLUSIONS

IVL seems to be a safe and effective strategy for lesion preparation in severely calcified lesions before stent implantation in coronary arteries. Future prospective studies are now warranted to compare IVL to other lesion preparation strategies.

Development of physiologically-informed computational coronary artery plaques for use in virtual imaging trials

BACKGROUND

As a leading cause of death, worldwide, cardiovascular disease is of great clinical importance. Among cardiovascular diseases, coronary artery disease (CAD) is a key contributor, and it is the attributed cause of death for 10% of all deaths annually. The prevalence of CAD is commensurate with the rise in new medical imaging technologies intended to aid in its diagnosis and treatment. The necessary clinical trials required to validate and optimize these technologies require a large cohort of carefully controlled patients, considerable time to complete, and can be prohibitively expensive. A safer, faster, less expensive alternative is using virtual imaging trials (VITs), utilizing virtual patients or phantoms combined with accurate computer models of imaging devices.

PURPOSE

In this work, we develop realistic, physiologically-informed models for coronary plaques for application in cardiac imaging VITs.

METHODS

Histology images of plaques at micron-level resolution were used to train a deep convolutional generative adversarial network (DC-GAN) to create a library of anatomically variable plaque models with clinical anatomical realism. The stability of each plaque was evaluated by finite element analysis (FEA) in which plaque components and vessels were meshed as volumes, modeled as specialized tissues, and subjected to the range of normal coronary blood pressures. To demonstrate the utility of the plaque models, we combined them with the whole-body XCAT computational phantom to perform initial simulations comparing standard energy-integrating detector (EID) CT with photon-counting detector (PCD) CT.

RESULTS

Our results show the network is capable of generating realistic, anatomically variable plaques. Our simulation results provide an initial demonstration of the utility of the generated plaque models as targets to compare different imaging devices.

CONCLUSIONS

Vast, realistic, and variable CAD pathologies can be generated to incorporate into computational phantoms for VITs. There they can serve as a known truth from which to optimize and evaluate cardiac imaging technologies quantitatively.

A Randomized Comparison of the Healing Response Between the Firehawk Stent and the Xience Stent in Patients With ST-Segment Elevation Myocardial Infarction at 6 Months of Follow-Up (TARGET STEMI OCT China Trial): An Optical Coherence Tomography Study

Background

The healing response of the Firehawk stent in patients with ST-segment elevation myocardial infarction (STEMI) remains unclear.

Aim

We compared the vascular healing of a biodegradable polymer sirolimus-eluting stent (Firehawk) vs. a durable polymer everolimus-eluting stent (Xience) at 6 months after percutaneous coronary intervention (PCI) in patients with STEMI.

Methods

In this prospective, multicenter, randomized, non-inferiority study, patients within 12 h of STEMI onset were randomized in a ratio of 1:1 to receive Firehawk or Xience stents. Optical coherence tomography (OCT) follow-up was performed 6 months after the index procedure and assessed frame by frame. The primary endpoint was the neointimal thickness (NIT) at 6 months evaluated by OCT. The safety endpoint was target lesion failure (TLF) at 12 months.

Results

The Firehawk stent was non-inferior to the Xience stent in terms of the neointimal thickness (73.03 ± 33.30 μm vs. 78.96 ± 33.29 μm; absolute difference: −5.94 [one-sided 95% lower confidence bound: −23.09]; P_{non−inferiority} < 0.001). No significant difference was observed between the Firehawk and Xience groups regarding the percentage of uncovered struts (0.55 [0.08, 1.32]% vs. 0.40 [0.21, 1.19]%, P = 0.804), the percentage of malapposed struts (0.17 [0.00, 1.52]% vs. 0.17 [0.00, 0.69]%, P = 0.662), and the healing score (1.56 [0.23, 5.74] vs. 2.12 [0.91, 3.81], P = 0.647). At 12 months, one patient in the Firehawk group experienced a clinically indicated target lesion revascularization. No other TLF events occurred in both groups. Independent risk factors of the NIT included body mass index, hyperlipidemia, B2/C lesions, thrombus G3–G5, thrombus aspiration, and postdilation pressure.

Conclusion

In patients with STEMI, Firehawk was non-inferior to Xience in vascular healing at 6 months. Both stents exhibited nearly complete strut coverage, moderate neointimal formation, and minimal strut malapposition.

Clinical Trial Number

NCT04150016.

Risk factors associated with intra-stent restenosis after percutaneous coronary intervention

The present study aimed to explore the correlations between clinical, biological, imagistic and procedural factors with the risk of intra-stent restenosis (ISR) in coronary artery disease (CAD) patients after percutaneous coronary intervention (PCI). An observational cross-sectional study was conducted in a high-volume PCI center over a period of 2 years. A total of 235 consecutive patients diagnosed with angina or acute coronary syndrome treated by PCI were included in the study. Diagnosis of ISR was documented by coronary angiography in patients with suggestive coronary symptoms and ischemic changes in non-invasive or invasive paraclinical investigations. Thus, they were assigned to two groups: With or without ISR. All patients underwent clinical and laboratory examination, providing clinical and paraclinical variables that could be considered risk factors for ISR. Current smokers [risk ratio (RR)=1.63; 95% confidence interval (95% CI): 1.25-2.13], arterial hypertension (RR=1.86; 95% CI: 1.41-2.45), diabetes (RR=1.83; 95% CI: 1.42-2.36), high C-reactive protein (CRP) levels (RR=1.44; 95% CI: 0.93-2.24), chronic kidney disease (CKD) (RR=1.90; 95% CI: 1.53-2.36) and thrombolysis in myocardial infarction (TIMI) score were found to have a significant role in estimating the risk for ISR. Moreover, the ISR group (119 patients) presented with a lower stent inflation pressure when compared to the control group (116 patients) (14.47 vs. 16.14 mmHg, P=0.004). An increased mean stent diameter used for PCI was not associated with a high ISR incidence (P=0.810) as well as complex coronary treated lesions with longer stents (mean length of 24.98 mm in patients without ISR vs. 25.22 mm in patients with ISR; P=0.311). There was an estimated two times higher risk (RR=2.13; 95% CI: 1.17-3.88) concerning multi-stenting and restenosis degree >70%. To conclude, smoking, hypertension, diabetes mellitus, high CRP levels, CKD, TIMI score, stent type, low pressure for stent implantation and multi-stenting were found to be associated with ISR in patients following PCI. Therefore, a close follow-up should be targeted in such patients.

Randomized Clinical Comparison of the Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Combo Stent With the Sirolimus-Eluting Orsiro Stent in Patients Treated With Percutaneous Coronary Intervention: The SORT OUT X Trial

BACKGROUND

Target lesion failure remains an issue with contemporary drug-eluting stents. Thus, the dual-therapy sirolimus-eluting and CD34+ antibody-coated Combo stent (DTS) was designed to further improve early healing. This study aimed to investigate whether the DTS is noninferior to the sirolimus-eluting Orsiro stent (SES) in an all-comers patient population.

METHODS

The SORT OUT X (Combo Stent Versus Orsiro Stent) trial, was a large-scale, randomized, multicenter, single-blind, 2-arm, noninferiority trial with registry-based follow-up. The primary end point target lesion failure was a composite of cardiac death, myocardial infarction, or target lesion revascularization within 12 months, analyzed using intention-to-treat. The trial was powered for assessing target lesion failure noninferiority of the DTS compared with the SES with a predetermined noninferiority margin of 0.021.

RESULTS

A total of 3146 patients were randomized to treatment with the DTS (1578 patients; 2008 lesions) or SES (1568 patients; 1982 lesions). At 12 months, intention-to-treat analysis showed that 100 patients (6.3%) assigned the DTS and 58 patients (3.7%) assigned the SES met the primary end point (absolute risk difference, 2.6% [upper limit of 1-sided 95% CI, 4.1%]; P (noninferiority)=0.76). The SES was superior to the DTS (incidence rate ratios for target lesion failure, 1.74 [95% CI, 1.26-2.41]; P=0.00086). The difference was explained mainly by a higher incidence of target lesion revascularization in the DTS group compared with the SES group (53 [3.4%] vs. 24 [1.5%]; incidence rate ratio, 2.22 [95% CI, 1.37-3.61]; P=0.0012).

CONCLUSIONS

The DTS did not confirm noninferiority to the SES for target lesion failure at 12 months in an all-comer population. The SES was superior to the DTS mainly because the DTS was associated with an increased risk of target lesion revascularization. However, rates of death, cardiac death, and myocardial infarction at 12 months did not differ significantly between the 2 stent groups. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03216733.

Ridaforolimus eluting stent for the treatment of Japanese patients with coronary disease: 1 year outcomes of the JNIR study

BACKGROUND

Japanese patients have shown improved outcomes after treatment with drug eluting stents compared with Western patients. Outcomes with the ridaforolimus-eluting EluNIR stent in Japanese patients are unknown.

METHODS AND RESULTS

This was a multi-center trial in Japanese patients undergoing PCI with the ridaforolimus eluting EluNIR stent. A propensity-score matched analysis was performed with the EluNIR arm of the BIONICS trial. The matched cohort was compared with the Japanese patients for the primary endpoint of target lesion failure (TLF) in a non-inferiority study. 104 Japanese patients were compared with 410 matched patients from BIONICS. Baseline characteristics were similar except for more frequent multi-vessel disease in the BIONICS cohort. Post dilation was more likely in Japanese patients (90.4% vs. 64.6%, p < 0.001). TLF at 12 months was met by 2 patients (1.9%) in the JNIR study compared with 5.3% in the BIONICS group (Pnoninf = 0.0028). Rates of MI (0% vs. 4.7%, p = 0.03), target vessel MI (0% vs. 3.7%, p = 0.04), MACE (1.0% vs. 6.2%, p = 0.03) and TVF (1.0% vs. 6.9%, p = 0.02) were all significantly lower among Japanese patients.

CONCLUSION

Treatment of Japanese patients with the EluNIR stent is associated with very low rates of adverse events, significantly fewer than seen in the BIONICS trial.

Soft Miniaturized Actuation and Sensing Units for Dynamic Force Control of Cardiac Ablation Catheters

Recently, there has been active research in finding robotized solutions for the treatment of atrial fibrillation (AF) by augmenting catheter systems through the integration of force sensors at the tip. However, limited research has been aimed at providing automatic force control by also integrating actuation of the catheter tip, which can significantly enhance safety in such procedures. This article solves the demanding challenge of miniaturizing both actuation and sensing for integration into flexible catheters. Fabrication strategies are presented for a series of novel soft thick-walled cylindrical actuators, with embedded sensing using eutectic gallium-indium. The functional catheter tips have a diameter in the range of 2.6-3.6 mm and can both generate and detect forces in the range of < 0.4 N, with a bandwidth of 1-2 Hz. The deformation modeling of thick-walled cylinders with fiber reinforcement is presented in the article. An experimental setup developed for static and dynamic characterization of these units is presented. The prototyped units were validated with respect to the design specifications. The preliminary force control results indicate that these units can be used in tracking and control of contact force, which has the potential to make AF procedures much safer and more accurate.

Post-dilatation improves stent apposition in patients with ST-segment elevation myocardial infarction receiving primary percutaneous intervention: A multicenter, randomized controlled trial using optical coherence tomography

BACKGROUND

Stent failure is more likely in the lipid rich and thrombus laden culprit lesions underlying ST-segment elevation myocardial infarction (STEMI). This study assessed the effectiveness of post-dilatation in primary percutaneous coronary intervention (pPCI) for acute STEMI.

METHODS

The multi-center POST-STEMI trial enrolled 41 consecutive STEMI patients with symptom onset <12 hours undergoing manual thrombus aspiration and Promus Element stent implantation. Patients were randomly assigned to control group (n=20) or post-dilatation group (n=21) in which a non-compliant balloon was inflated to >16 atm pressure. Strut apposition and coverage were evaluated by optical coherence tomography (OCT) after intracoronary verapamil administration via thrombus aspiration catheter, post pPCI and at 7-month follow-up. The primary endpoint was rate of incomplete strut apposition (ISA) at 7 months after pPCI.

RESULTS

There were similar baseline characteristics except for stent length (21.9 [SD 6.5] mm vs. 26.0 [SD 5.8] mm, respectively, P=0.03). In post-dilatation vs. control group, ISA rate was lower (2.5% vs. 4.5%, P=0.04) immediately after pPCI without affecting final TIMI flow 3 rate (95.2% vs. 95.0%, P>0.05) or corrected TIMI frame counts (22.6±9.4 vs. 22.0±9.7, P>0.05); and at 7-month follow-up (0.7% vs. 1.8%, P<0.0001), the primary study endpoint, with similar strut coverage (98.5% vs. 98.4%, P=0.63) and 1-year rate of major adverse cardiovascular events (MACE).

CONCLUSION

In STEMI patients, post-dilatation after stent implantation and thrombus aspiration improved strut apposition up to 7 months without affecting coronary blood flow or 1-year MACE rate. Larger and longer term studies are warranted to further assess safety (ClinicalTrials.gov identifier: NCT02121223).

Feasibility and safety of jailed-pressure wire technique using durable optical fiber pressure wire for intervention of coronary bifurcation lesions

OBJECTIVES

The objective was to evaluate the safety, feasibility, and accuracy of the jailed-pressure wire technique using a durable optical fiber-based pressure wire with high-pressure dilatation using a non-compliant balloon after main vessel stenting.

BACKGROUND

Fractional flow reserve (FFR) information can help interventionists determine whether they should treat a jailed-side branch (SB). However, re-crossing a pressure wire into a jailed-SB is sometimes technically difficult.

METHODS

Fifty-one consecutive lesions from 48 patients who underwent the jailed-pressure wire technique were retrospectively investigated. The primary endpoint was complication rate and secondary endpoints included success rate of FFR measurement, incidence of wire disruption, and final drift rate. The usability of FFR for percutaneous coronary intervention of coronary bifurcation lesion was also evaluated.

RESULTS

Median age of the patients was 69 years and 80.4% were men. The most frequent underlying disease was stable angina (70.6%) and 68.6% were type B2 lesions. Our main findings were: the procedure was performed successfully in all cases without any complications or wire disruption, FFR could be measured without significant final drift in 95.9% of cases, and FFR measurements helped interventionists determine whether to perform a final kissing balloon dilatation in 49.0% cases.

CONCLUSIONS

The jailed-pressure wire technique using a durable optical fiber-based pressure wire with high-pressure post-dilatation maneuver was safe, feasible, and accurate.

The effects of types of guidewires and pressure applied during stent implantation in the main vessel on the incidence of damage to coronary guidewires during angioplasty of coronary bifurcation lesions-Wide Beast study

OBJECTIVES

We evaluated the impact of stent inflation pressure and type of guidewire on "jailed" coronary guidewire damage occurring during bifurcation angioplasty.

BACKGROUND

Despite new techniques and treatment options during percutaneous coronary intervention (PCI) we still observe peri- and postoperative complications for to various known and unknown reasons.

METHODS

Patients undergoing PCI within the coronary bifurcation were randomly assigned to one of four groups: Pilot 50 or BMW guidewire and pressure ≤12 or >12 atm. After PCI each "jailed" guidewire was evaluated under an optical microscope. The Wide Beast Scale (WBS) was developed for the internal purposes of the study and was used for qualitative assessment. Also, the inflation pressure, the patients' characteristics and the technical parameters of the procedure were recorded.

RESULTS

The clinical characteristics were similar in all the groups. There was no statistical significance of the degree of damage, rated on the WBS, for either guidewire group with respect to inflation pressure (P = 0.49). The prevalence of guidewire damage was higher in the BMW versus the Pilot 50 group (98.4% vs 67.4% respectively, P = 0.00001) as was the severity of the damage (grades 3 and 4) in BMW versus Pilot 50 (55.6% vs 13.0% respectively, P = 0.00001).

CONCLUSIONS

The inflation pressure during stent implantation had no impact on "jailed" guidewire damage. The difference in the prevalence of serious damage and total damage number was statistically significant for the BMW guidewire compared to the Pilot50. The BMW guidewire was an independent predictor of the degree of damage to the guidewire.

Effect of Post-Dilatation Following Primary PCI With Everolimus-Eluting Bioresorbable Scaffold Versus Everolimus-Eluting Metallic Stent Implantation: An Angiographic and Optical Coherence Tomography TROFI II Substudy

OBJECTIVES

This study sought to investigate the effect of post-dilatation on angiographic and intracoronary imaging parameters in the setting of primary percutaneous coronary intervention comparing the everolimus-eluting bioresorbable scaffold (BRS) with the everolimus-eluting metallic stent (EES).

BACKGROUND

Routine post-dilatation of BRS has been suggested to improve post-procedural angiographic and subsequent device-related clinical outcomes.

METHODS

In the ABSORB STEMI TROFI II trial, 191 patients with ST-segment elevation myocardial infarction were randomly assigned to treatment with BRS (n = 95) or EES (n = 96). Minimal lumen area and healing score as assessed by optical coherence tomography at 6 months were compared between BRS- and EES-treated patients stratified according to post-dilatation status.

RESULTS

Primary percutaneous coronary intervention with post-dilatation was performed in 48 (50.5%) BRS- and 25 (25.5%) EES-treated lesions. There were no differences in baseline characteristics and post-procedural minimal lumen diameter between groups. In the BRS group, lesions with post-dilatation were associated with a trend toward a smaller minimal lumen area at 6 months (5.07 ± 1.68 mm² vs. 5.72 ± 1.77 mm²; p = 0.09) and significantly larger angiographic late lumen loss (0.28 ± 0.34 mm vs. 0.12 ± 0.25 mm; p = 0.02), whereas no difference was observed in the EES arm (5.46 ± 2.18 mm² vs. 5.55 ± 1.77 mm²; p = 0.85). The neointimal healing score was low and comparable between groups with and without post-dilation (BRS: 1.55 ± 2.61 vs. 1.92 ± 2.17; p = 0.48; EES: 2.50 ± 3.33 vs. 2.90 ± 4.80; p = 0.72).

CONCLUSIONS

In the setting of selected patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention with BRS or EES, post-dilatation did not translate into larger lumen area or improved arterial healing at follow-up. (ABSORB STEMI: The TROFI II; NCT01986803).

Impact of very high pressure stent deployment on angiographic and long-term clinical outcomes in true coronary bifurcation lesions treated by the mini-crush stent technique: A single center experience

Background

Percutaneous coronary intervention (PCI) for bifurcation lesions (BL) using 2 stents technique is known to be associated with high rates of procedural failure especially on the side branch (SB) mainly due to stent incomplete apposition. Stent deployment at very high pressure (SDHP) may lead to better stent expansion and apposition. However, SDHP may also be at the origin of deeper wall injury resulting into major cardiac adverse events. No data are available on evaluation of SDHP in BL treated by a mini-crush stent technique.

Methods

One hundred and thirteen consecutive patients underwent PCI for BL (Medina 1, 1, 1) using a mini-crush stent technique with SDHP defined as ≥20 atm. An angiographic follow-up was performed at 6 month and clinical follow-up was obtained at a median of 3 years.

Results

Stent deployment mean pressures were 20 ± 1.4 atm (range 20–25) in the main vessel (MV) and 20 ± 1.5 atm (range 20–25) in SB. Simultaneous final kissing balloon was used in 92% of cases. PCI was successful in 100%. Angiographic follow-up was obtained in 83% of patients. Restenosis rate was 13% (12% restenosis in the SB) with only one case (0.8%) of SB probable thrombosis. Another case of late stent thrombosis occurred at a 3 years clinical follow-up.

Conclusion

Compared with previously published studies in which stents were deployed at lower pressure, SDHP does not increase the restenosis rate in BL using mini-crush stent technique but seems to reduce the rate of stent thrombosis.

A Comparison of Peri-Procedural Myocardial Infarction between Paclitaxel-Coated Balloon and Drug-Eluting Stent on De Novo Coronary Lesions

PURPOSE

This study compared the impact of paclitaxel-coated balloons (PCB) or drug eluting stents (DES) on peri-procedural myocardial infarction (PMI) on de novo coronary lesion in stable patients.

MATERIALS AND METHODS

In this observational study, we compared the incidence of PMI amongst patients with single vessel de novo coronary lesions who underwent treatment with a PCB or DES. Propensity score-matching analysis was used to assemble a cohort of patients with similar baseline characteristics. PMI was classified as myocardial infarction occurring within 48 hours after percutaneous coronary intervention with a threshold of 5 x the 99th percentile upper reference limit of normal for creatine kinase-myocardial band (CK-MB) or troponin T (TnT).

RESULTS

One hundred four patients (52 receiving PCB and 52 receiving DES) were enrolled in this study. The peak mean values of CK-MB and TnT were significantly higher in the DES group. There was a significantly higher rate of PMI in the DES group (23.1% vs. 1.9%, p=0.002). Total occlusion of the side-branch occurred in two patients treated with DES, while no patients treated with PCB. In multivariable analysis, DES was the only independent predictor of PMI compared with PCB (odds ratio 42.85, 95% confidence interval: 3.44-533.87, p=0.004).

CONCLUSION

Treatment with a PCB on de novo coronary lesion might be associated with a significant reduction in the risk of PMI compared to DES.

Impact of Implantation Technique and Plaque Morphology on Strut Embedment and Scaffold Expansion of Polylactide Bioresorbable Scaffold - Insights From ABSORB Japan Trial

BACKGROUND

The optimal implantation technique for the bioresorbable scaffold (Absorb, Abbott Vascular) is still a matter of debate. The purpose of the present study was to evaluate the effect of implantation technique on strut embedment and scaffold expansion.Methods and Results:Strut embedment depth and scaffold expansion index assessed by optical coherence tomography (OCT) (minimum scaffold area/reference vessel area) were evaluated in the ABSORB Japan trial (OCT subgroup: 87 lesions) with respect to implantation technique using either quantitative coronary angiography (QCA) or OCT. Strut embedment was assessed at the strut level (n=667), while scaffold expansion was assessed at the lesion level (n=81). The mean embedment depth was 63±59 µm. Balloon sizing and inflation pressure had no direct effect on strut embedment. Plaque morphology affected strut embedment [nonatherosclerotic (58.9±54.3 µm), fibroatheroma (73.3±59.6 µm), fibrous plaque (59.7±51.1 µm), and fibrocalcific plaque (-3.1±61.6 µm, negative value means malapposition), P <0.001]. The balloon-artery ratio positively correlated with the expansion index. This relationship was stronger when the OCT-derived reference vessel diameter (RVD) was used as a reference for balloon selection rather than the QCA-derived one [predilatation (Pearson correlation r: QCA: 0.167 vs. OCT: 0.552), postdilatation (QCA: 0.316 vs. OCT: 0.717)].

CONCLUSIONS

Underlying plaque morphology influenced strut embedment, whereas implantation technique had no direct effect on it. Optimal balloon sizing based on OCT-derived RVD might be recommended. However, the safety of such a strategy should be investigated in a prospective trial. (Circ J 2016; 80: 2317-2326).

Optical coherence tomography versus intravascular ultrasound to evaluate stent implantation in patients with calcific coronary artery disease

AIMS

Stent underexpansion and malapposition are associated with adverse outcomes following percutaneous coronary intervention, but detection and treatment can be challenging in the presence of extensive coronary artery calcification. Frequency domain optical coherence tomography (FD-OCT) is a novel intravascular imaging technique with greater spatial resolution than intravascular ultrasound (IVUS) but its role in the presence of extensive coronary calcification remains unclear. We sought to determine the utility of FD-OCT compared to IVUS imaging to guide percutaneous coronary intervention in patients with severe calcific coronary artery disease.

METHODS

18 matched IVUS and FD-OCT examinations were evaluated following coronary stent implantation in 12 patients (10 male; mean age 70±7 years) undergoing rotational atherectomy for symptomatic calcific coronary artery disease.

RESULTS

In-stent luminal areas were smaller (minimum in-stent area 6.77±2.18 vs 7.19±2.62 mm(2), p<0.05), while reference lumen dimensions were similar with FD-OCT compared with IVUS. Stent malapposition was detected in all patients by FD-OCT and in 10 patients by IVUS. The extent of stent malapposition detected was greater (20% vs 6%, p<0.001) with FD-OCT compared to IVUS. Postdilation increased the in-stent luminal area (minimum in-stent area: 8.15±1.90 vs 7.30±1.62 mm(2), p<0.05) and reduced the extent of stent malapposition (19% vs 34%, p<0.005) when assessed by FD-OCT, but not IVUS.

CONCLUSIONS

Acute stent malapposition occurs frequently in patients with calcific coronary disease undergoing rotational atherectomy and stent implantation. In the presence of extensive coronary artery calcification, FD-OCT affords enhanced stent visualisation and detection of malapposition, facilitating improved postdilation stent apposition and minimal luminal areas.

TRIAL REGISTRATION NUMBER

NCT02065102.

Analysis of the stent expansion in a stenosed artery using finite element method: application to stent versus stent study

In this article, finite element method is used to investigate the mechanical behavior of a stent and to determine the biomechanical interaction between the stent and the artery in a stenting procedure. The main objective of this study is to reach to a model close to a real condition of coronary stent placement. Unlike most of the models proposed in the literature, all the steps of the deployment of a stent in the stenotic vessel (i.e. pressure increasing, constant load pressure and pressure decreasing) are simulated in this article to show the behavior of the stent in different stages of implantation. The results indicate that the first step of deployment, that is, pressure increasing, plays a main role in the success of stent implantation. So that, in order to compare the behavior of different types of stents, it is sufficient to compare their behavior at the end of pressure increasing step. In order to show the application of the findings in stent versus stent studies, three commercially available stents (the Palmaz-Schatz, Multi-Link and NIR stents) are modeled and their behavior is compared at the end of pressure increasing step. The effect of stent design on the restenosis rate is investigated. According to the findings, the possibility of restenosis is lower for Multi-Link and NIR stents in comparison with Palmaz-Schatz stent which is in good agreement with clinical results. Therefore, the testing methodology outlined here is proposed as a simple and economical alternative for "stent versus stent" complicated clinical trials.

A finite element study on variations in mass transport in stented porcine coronary arteries based on location in the coronary arterial tree

Drug-eluting stents have a significant clinical advantage in late-stage restenosis due to the antiproliferative drug release. Understanding how drug transport occurs between coronary arterial locations can better help guide localized drug treatment options. Finite element models with properties from specific porcine coronary artery sections (left anterior descending (LAD), right (RCA); proximal, middle, distal regions) were created for stent deployment and drug delivery simulations. Stress, strain, pore fluid velocity, and drug concentrations were exported at different time points of simulation (0-180 days). Tests indicated that the highest stresses occurred in LAD sections. Higher-than-resting homeostatic levels of stress and strain existed at upwards of 3.0 mm away from the stented region, whereas concentration of species only reached 2.7 mm away from the stented region. Region-specific concentration showed 2.2 times higher concentrations in RCA artery sections at times corresponding to vascular remodeling (peak in the middle segment) compared to all other segments. These results suggest that wall transport can occur differently based on coronary artery location. Awareness of peak growth stimulators and where drug accumulation occurs in the vasculature can better help guide local drug delivery therapies.

Effect of stent inflation pressure and post-dilatation on the outcome of coronary artery intervention. A report of more than 90,000 stent implantations

Background

Percutaneous coronary intervention (PCI) stent inflation pressure correlates to angiographic lumen improvement and stent expansion but the relation to outcome is not clarified. Using comprehensive registry data our aim was to evaluate how stent inflation pressure influences restenosis, stent thrombosis and death following PCI.

Methods

We evaluated all consecutive coronary stent implantations in Sweden during 46 months from 2008 using data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). We used logistic regression and Cox proportional hazard modeling to estimate risk of outcomes with different balloon pressures.

Results

In total, 93 697 stents were eligible for analysis and divided into five different pressure interval groups: ≤15 atm, 16–17 atm, 18–19 atm, 20–21 atm and ≥22 atm. The risks of stent thrombosis and restenosis were significantly higher in the ≤15 atm, 18–19 atm and ≥22 atm groups (but not in the 16–17 atm group) compared to the 20–21 atm group. There were no differences in mortality. Post-dilatation was associated with a higher restenosis risk ratio (RR) of 1.22 (95% confidence interval (CI) 1.14–1.32, P<0.001) but stent thrombosis did not differ statistically between procedures with or without post-dilatation. The risk of death was lower following post-dilatation (RR 0.81 (CI 0.71–0.93) P = 0.003) and the difference compared to no post-dilatation was seen immediately after PCI.

Conclusion

Our retrospective study of stent inflation pressure identified a possible biological pattern—the risks of stent thrombosis and of restenosis appeared to be higher with low and very high pressures. Post-dilatation might increase restenosis risk.

Predictors of in-stent stenosis and occlusion after endovascular treatment of intracranial vascular disease with the Willis covered stent

Covered stent placement has emerged as a promising therapeutic option for intracranial vascular lesions. However, in-stent stenosis and occlusion continue to be important concerns with the use of a covered stent, which is more thrombogenic than other types of stents. The purpose of this study was to determine predictors of in-stent stenosis and occlusion for covered stents used in the treatment of intracranial vascular diseases. Clinical, procedural and angiographic data of 46 patients with 49 intracranial vascular lesions treated with the Willis covered stent (Micro-Port, Shanghai, China) between April 2005 and October 2010 were collected and analyzed retrospectively. Univariate analysis and multivariate logistic regression analysis were performed to determine the factors predictive of in-stent stenosis and/or occlusion of the stents. In-stent stenosis and/or occlusion were documented at angiography in six patients with six lesions, and no stenoses or occlusions were seen at angiography in the remaining 40 patients with 43 lesions. Univariate analysis revealed that hypertension, post-procedure irregular antiplatelet therapy and cerebrovascular arteriosclerosis were associated with in-stent stenosis and/or occlusion. By multivariate logistic regression analysis, post-procedure irregular antiplatelet therapy (odds ratio [OR]=15; 95% confidence interval [CI], 1.172-192.004; p=0.037) and cerebrovascular arteriosclerosis (OR=19; 95% CI, 1.374-262.659; p=0.028) were independent predictors of in-stent stenosis and/or occlusion. Thus, post-procedure irregular antiplatelet therapy and coexistent cerebrovascular arteriosclerosis appear to increase the risk of in-stent stenosis and/or occlusion of covered stents in the treatment of intracranial vascular disease.

Discrepancy between morphologic and functional criteria of optimal stent deployment using intravascular ultrasound and pressure derived myocardial fractional flow reserve

BACKGROUND

Pressure derived myocardial FFR, a functional index of epicardial stenosis has been proposed for the assessment of optimal stent deployment. The following study evaluated the potential of serial fractional flow reserve (FFR) measurements in comparison to the 'gold standard' intravascular ultrasound (IVUS) for optimal stent deployment and its long-term outcome.

METHODS

35 patients with a single de novo lesion underwent PTCA followed by stent implantation with an initial inflation pressure of 12 atm. If optimal stent expansion using IVUS-criteria were not fulfilled, re-dilatation at 16 atm as well as additional inflations with larger balloon sizes were performed to reach the procedural end-point. IVUS and FFR were performed after each dilatation (n = 136). Angiography was repeated after 6 months.

RESULTS

In 30 pts who fulfilled IVUS criteria, mean lumen area (2.9+/-1.3 mm2) increased after PTCA and stent implantation to 10.0+/-3.0 mm2. In six pts, optimum stent deployment according to a value of FFR0.94 was not reached. Four of six pts reached the IVUS criteria at 12 atm and two pts at 16 atm, respectively. Positive and negative predictive values of FFR were 26 and 64%. Three of the 30 pts (10%) revealed a restenosis at three months follow-up. One of these restenosis was seen in a patient with a post-procedural FFR<0.94.

CONCLUSIONS

FFR was not valid to predict optimal stent expansion according to IVUS criteria but could delineate under-expanded stents despite a reasonable angiographic appearance. Morphologic (IVUS) and functional criteria (FFR) for optimal stent deployment revealed a comparably low restenosis rate.

Clinical effectiveness of bare-metal stenting compared with balloon angioplasty in total coronary occlusions: insights from a systematic overview of randomized trials in light of the drug-eluting stent era

BACKGROUND

We sought to compare, using meta-analytic techniques, bare-metal stent versus balloon angioplasty in the percutaneous treatment of total coronary occlusions by means of a quantitative systematic review and to indicate new avenues for future treatments.

METHODS

MEDLINE and CENTRAL were searched. Inclusion criteria were random allocation, prospective comparison, and intention to treat. Random-effect odds ratios (ORs) with 95% confidence intervals (CIs) for death, myocardial infarction (MI), repeated revascularization, major adverse cardiac events (MACE), and angiographic restenosis and reocclusion were computed.

RESULTS

Nine trials (1409 patients) were included. Death rate was not different in the 2 groups, 0.4% after stenting versus 0.7% after balloon angioplasty (OR 0.72, 95% CI 0.21-2.50). MI rate was significantly increased after stenting (6.7% vs 3.4%, OR 2.06, 95% CI 1.22-3.46), mainly because of a higher rate of periprocedural non-Q-wave MI. By contrast, the risk of repeated revascularization was significantly reduced by stenting (17% vs 32%, OR 0.41, 95% CI 0.31-0.53). This yielded to an overall reduction in the rate of MACE after stenting (23.2% vs 35.4%, OR 0.49, 95% CI 0.36-0.68). Angiographic restenosis and reocclusion were also decreased by stent (41.1% vs 60.9%, OR 0.36, 95% CI 0.23-0.57; 6.8% vs 16%, OR 0.36, 95% CI 0.22-0.59, respectively).

CONCLUSIONS

In total coronary occlusions, stenting yields an important benefit over balloon angioplasty in reduction of MACE, repeated revascularizations, and angiographic restenosis and reocclusion. However, these events remain frequent. Moreover, the finding of an increased rate of periprocedural minor myocardial damage after stenting casts caution. New strategies aimed to reduce the need of repeated revascularizations and periprocedural MIs should be further investigated.

Influence of stent surface topography on the outcomes of patients undergoing coronary stenting: A randomized double-blind controlled trial

The objective of this study was to examine the relationship between stent surface topography and outcome in patients undergoing implantation of stents with rough and smooth surfaces. Surface topography is considered an important determinant of the bare stent performance. Specifically designed rough surface may increase the drug-storing capacity of stents but its direct impact on the risk of thrombosis and restenosis is not known. A total of 200 patients with significant stenosis in native coronary vessels were randomly assigned in a double-blind way to receive either a rough or a smooth-surface stent. The primary endpoint of the study was late lumen loss. Secondary endpoints included angiographic restenosis and clinical outcomes. The study was designed to test the equivalence of rough-surface stents to smooth-surface stents with respect to late lumen loss based on a noninferiority margin of 0.20 mm. Follow-up angiography was performed in 77% of the patients. Late lumen loss was 1.0 +/- 0.7 mm in the rough-surface stent group and 1.2 +/- 0.7 mm in the smooth stent surface group with a mean difference of -0.20 mm (95% CI = -0.43 to 0.02) between the two stents (P < 0.001 from test for equivalence and P = 0.08 from test for superiority). Angiographic restenosis rates were 25% with rough-surface stents and 35% with smooth-surface stents (P = 0.19). These results show that a rough stent surface does not increase late lumen loss after stent implantation as compared with a conventional smooth stent surface.

Short- and long-term clinical outcome after various stent implantation: Overview of the results of uni- and multicenter stent registries

The present study reports the results of the short- and long-term outcomes of prospective uni- and multicenter stent registries: Palmaz-Schatz (n = 140 patients), Ave-Micro and GFX (n = 280), Multilink Duet (n = 340), Multilink Tetra (n = 192), and Carbo (n = 140) Stent Registries, as well as the predictors and angiographic cutoff points predicting major adverse cardiac events (MACE) after different stent implantations. Significant decrease in subacute stent thrombosis (from 2.9% to 0) and MACE (from 35% to 8.3%) occurred as the improved stents, optimized stent implantation technique, and new postintervention drug therapy were introduced. The changes of angiographic cutoff values (postintervention minimal lumen diameter and preintervention reference diameter: from 2.9 and 3.1 mm for Palmaz-Schatz to 2.5 and 2.8 mm for Multilink Duet, Multilink Tetra, and Carbo stents) and clinical and angiographic factors predicting MACE indicated the change of traditional restenosis paradigm and that progress in clinical practice might be able to counterbalance unfavorable lesion and intervention-related characteristics.

Intracoronary stenting and angiographic results: Restenosis after direct stenting versus stenting with predilation in patients with symptomatic coronary artery disease (ISAR-DIRECT trial)

The objective of this randomized study was to assess whether direct stenting leads to less restenosis than does conventional stenting (CS) with predilation in clinical practice. We included 910 patients who were randomly assigned to undergo either direct stenting (DS; n = 456) or CS (n = 454). No significant difference was observed in the incidence of angiographic restenosis (primary endpoint): 23.6% for DS and 21.0% for CS (P = 0.41; relative risk = 1.1; 95% CI = 0.8-1.5). The incidence of target vessel revascularization was 17.3% among DS and 14.8% among CS patients (P = 0.29; relative risk = 1.2; 95% CI = 0.8-1.6). The combined incidence of death or myocardial infarction at one year was 9.0% in the DS group and 7.0% in the CS group (P = 0.28). In conclusion, direct stenting is not associated with any reduction of thrombotic and restenotic complications as compared to the conventional stenting.

Increased CK-MB release is a “trade-off” for optimal stent implantation

OBJECTIVES

We sought to determine the impact of aggressive stent expansion on creatine kinase-MB isoenzyme (CK-MB) release and clinical restenosis.

BACKGROUND

Elevation of CK-MB after percutaneous coronary interventions has been associated with late mortality.

METHODS

We identified 989 consecutive patients who underwent intravascular ultrasound-guided stenting of 1,015 coronary lesions. Patients were divided into three groups according to stent expansion, defined as the ratio of final lumen over the reference lumen cross-sectional areas: Group 1 (ratio <70%, n = 117 patients with 126 lesions); Group 2 (ratio 70% to 100%, n = 551 patients with 562 lesions); Group 3 (ratio >100%, n = 321 patients with 327 lesions).

RESULTS

The peak CK-MB values increased significantly with increasing stent expansion: CK-MB = 3 to 5x normal occurred 16%, 18%, and 25% in Groups 1, 2, and 3, respectively, p = 0.02; CK-MB >5 times normal occurred 9%, 13%, and 16% respectively, p = 0.02. Conversely, at one year follow-up there was a stepwise decrease in target lesion revascularization (11% vs. 19% and 17%, respectively, p = 0.04) and major adverse cardiac events with increasing stent expansion. In addition, there was a trend toward lower mortality in Group 3 (9% vs. 4.4% vs. 4.0%, p = 0.07).

CONCLUSIONS

Intravascular ultrasound-guided stent overexpansion (final lumen greater than reference lumen cross-sectional area) is accompanied by a higher periprocedural CK-MB release but a lower target lesion revascularization and a trend toward lower mortality at one year. Increased periprocedural CK-MB release appears as a trade-off for optimal stent implantation and lower clinical restenosis.

Intracoronary stenting and angiographic results: strut thickness effect on restenosis outcome (ISAR-STEREO-2) trial

OBJECTIVES

We tested the hypothesis that thinner-strut stents are associated with a reduced rate of restenosis when comparing two stents with different design.

BACKGROUND

We have previously shown that, for two stents with similar design, the risk for restenosis is dependent on the strut thickness. It is unknown whether strut thickness preserves its relevance as a determinant of restenosis even in the presence of different stent designs.

METHODS

A total of 611 patients with symptomatic coronary artery disease were randomly assigned to receive either the thin-strut ACS RX Multilink stent (Guidant, Advanced Cardiovascular Systems, Santa Clara, California) (strut thickness 50 microm, interconnected ring design; n = 309) or the thick-strut BX Velocity stent (Cordis Corp., Miami, Florida) (strut thickness 140 microm, closed cell design; n = 302). The primary end point was angiographic restenosis (> or =50% diameter stenosis at follow-up angiography). Secondary end points were the incidence of target-vessel revascularization (TVR) and the combined rate of death and myocardial infarction (MI) at one year.

RESULTS

The incidence of angiographic restenosis was 17.9% in the thin-strut group and 31.4% in the thick-strut group, relative risk, 0.57 (95% confidence interval, 0.39 to 0.84), p < 0.001. A TVR due to restenosis was required in 12.3% of the thin-strut group and 21.9% of the thick-strut group, relative risk, 0.56 (95% confidence interval, 0.38 to 0.84), p = 0.002. No significant difference was observed in the combined incidence of death and MI at one year.

CONCLUSIONS

When two stents with different design are compared, the stent with thinner struts elicits less angiographic and clinical restenosis than the thicker-strut stent.

Postprocedure chest pain after coronary stenting: implications on clinical restenosis

OBJECTIVES

The goal of this study was to analyze the incidence and predictors of postprocedure chest pain (PPCP) after percutaneous coronary intervention (PCI) and its correlation with clinical restenosis.

BACKGROUND

Chest pain after PCI occurs frequently even in the absence of procedural events and is considered to be due to vasospasm or coronary artery stretch. The short- and long-term significance of PPCP after otherwise successful stenting is not clear.

METHODS

We analyzed 1,362 patients undergoing coronary stenting for PPCP, procedural and in-hospital events, 30-day major adverse cardiac events, and target vessel revascularization (TVR) at 6 to 9 months.

RESULTS

There were 488 patients with PPCP and, of these, 312 patients were excluded due to procedural events. The remaining 176 patients with PPCP were compared with 874 patients without PPCP. Creatine kinase-MB isoenzyme elevation occurred in 25.6% of the PPCP group versus 9.6% of the no PPCP group (p < 0.001). Despite similar reference vessel diameter, the PPCP group had larger postprocedure minimum lumen diameter, higher stent-to-vessel ratio, and higher inflation pressure versus the no PPCP group (p < 0.01). At 30 days, the emergency room visits and repeat catheterization (16% vs. 2.7%; p < 0.001) were higher in the PPCP group versus the no PPCP group, but repeat intervention was similar. At 6- to 9-month follow-up, the TVR was significantly higher in the PPCP group compared with the no PPCP group (29.5% vs. 16.6%; p < 0.01).

CONCLUSIONS

Our analysis suggests micromyonecrosis and vessel stretch as causes of PPCP. Postprocedure chest pain is associated with similar short-term outcome as no PPCP, but has higher restenosis, perhaps mediated by deep vessel wall injury. Therefore, PPCP may identify patients at high risk for restenosis.

The contribution of "mechanical" problems to in-stent restenosis: An intravascular ultrasonographic analysis of 1090 consecutive in-stent restenosis lesions

OBJECTIVES

Serial intravascular ultrasonographic (IVUS) studies have shown that in-stent restenosis is the result of intimal hyperplasia (IH). However, routine preintervention IVUS imaging has suggested that many restenotic stents were inadequately deployed. The purpose of this IVUS study was to determine the incidence of mechanical problems contributing to in-stent restenosis (ISR).

METHODS

Between April 1994 and June 2000, 1090 patients with ISR were treated at the Washington Hospital Center. All underwent preintervention IVUS imaging. IVUS measurements included proximal and distal reference lumen areas and diameters; stent, minimum lumen, and IH (stent minus lumen) areas; and IH burden (IH/stent area).

RESULTS

In 49 ISR lesions (4.5%), there were morphologic findings that contributed to the restenosis. These were termed mechanical complications. Examples include (1) missing the lesion (eg, an aorto-ostial stenosis), (2) stent "crush," and (3) having the stent stripped off the balloon during the implantation procedure. Excluding mechanical complications, stent underexpansion was common. In 20% of the ISR cases the stents had a cross-sectional area (CSA) at the site of the lesion <80% of the average reference lumen area. Twenty percent of lesions had a minimum stent area <5.0 mm(2) and an additional 18% had a minimum stent area of 5.0 to 6.0 mm(2). Twenty-four percent of lesions had an IH burden <60%.

CONCLUSION

Mechanical problems related to stent deployment procedures contribute to a significant minority of ISR lesions (approximately 25%).

Diffuse in-stent restenosis

Stent restenosis, especially the diffuse pattern, has developed into a significant clinical and economical problem. It has been estimated that up to 250,000 patients developed in-stent restenosis in 2,000 alone, two thirds of them can be expected to have diffuse in-stent restenosis, which is difficult to treat because of high recurrence rates. None of the conventionally available interventional treatment modalities provides optimal long-term results. Intravascular radiation therapy is currently the only effective percutaneous therapy for combating in-stent restenosis. Late thrombotic complications have largely been eliminated by extended antiplatelet regimens. Geographical miss, a major reason for recurrence of in-stent restenosis after brachytherapy, can be reduced by an improved radiation technique. The first preliminary data on drug-eluting stents, showing only minimal neointimal proliferation at 6-month postimplantation, could represent a major breakthrough in the quest to solve restenosis.

Randomized comparison of J&J Crown stent versus NIR stent after routine coronary angioplasty

BACKGROUND

Coronary artery stents are used for the treatment of acute or threatening vessel occlusion complicating coronary angioplasty or for prevention of restenosis after angioplasty. The current randomized trial compared the procedural outcome and long-term patency of 2 different flexible stents in unselected lesion morphology.

METHODS

The study population consisted of consecutive patients undergoing coronary angioplasty for symptomatic coronary artery disease followed by high-pressure stent implantation. The poststent treatment consisted of antiplatelet therapy. The primary hypothesis was an assumed restenosis rate of 30% in the group receiving NIR stents (Boston Scientific Europe SPRL, Parc Industriel de Petit-Rechain, Belgium) and a reduction of the restenosis rate (defined as >50% vessel diameter at follow-up) by 50% in the group undergoing J&J Crown stent (Cordis, Johnson & Johnson Interventional Systems, Warren, NJ) implantation: the restenosis rate and minimal luminal diameter at follow-up. Follow-up angiography was performed 6 months after the initial procedure.

RESULTS

A total of 203 patients were randomized to receive either the J&J Crown stent (n = 103) or the NIR stent (n = 100). The procedural success was similar in both groups (96.1% vs 99% in the NIR stent group, respectively; P =.19). There were 4 cases of crossover from the J&J Crown to the NIR stent group. In one patient, stent implantation of either stent model did not succeed. One patient died from fulminant pulmonary embolism. Restenosis, defined as >50% diameter stenosis at follow-up 5.8 +/- 1.3 months after the initial procedure occurred in 19 patients (18.4%) in the J&J Crown stent group compared with 22 patients (22.0%) in the NIR stent group (P =.42). There was a significantly higher rate of crossover from the J&J Crown stent to the NIR stent (3.9% vs 0%, respectively, P =.047), whereas reverse crossover did not occur. The one lesion in which NIR stent implantation was not successful had an extremely tortuous proximal part. This patient underwent only balloon angioplasty. Clinical events were rare during 6 months of follow-up and the incidence did not differ between both groups (nonfatal myocardial infarction: J&J Crown stent 1.0% vs 0% in the NIR stent group, P =.32; all-cause mortality: J&J Crown stent 1.0% vs 0% in the NIR stent group, P =.32).

CONCLUSIONS

There were no significant angiographic and clinical differences between the J&J Crown and NIR stents. Both stents had a similar procedural success rate, although the implantation of NIR stents was successful even in vessels in which previous attempts at J&J Crown stent placement had failed.

Treatment of Chlamydia pneumoniae infection with roxithromycin and effect on neointima proliferation after coronary stent placement (ISAR-3): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Vascular infection with Chlamydia pneumoniae might boost inflammatory responses that play a pivotal part in neointima formation, which is the main cause of restenosis after stenting. Our aim was to investigate whether or not treatment of C pneumoniae infection with antibiotics prevents restenosis after coronary stent placement.

METHODS

We enrolled 1010 consecutive patients with successful coronary stenting into a randomised, double-blind trial. Patients received the macrolide antibiotic roxithromycin 300 mg once daily for 28 days (506), or placebo (504). Primary endpoint was frequency of restenosis (diameter stenosis >50%) at follow-up angiography, and secondary endpoint was rate of target vessel revascularisation during the year after stenting. A prespecified secondary analysis addressed treatment effect with respect to titre of C pneumoniae in serum. Analysis was by intention to treat.

FINDINGS

Rate of angiographic restenosis was 31% (157 lesions) in the roxithromycin group and 29% (148) in the placebo group (relative risk 1.08 [95% CI 0.92-1.26]; p50.43), corresponding to a rate of target vessel revascularisation of 19% (120) and 17% (105), respectively (1.13 [0.95-1.36]; p50.30). The combined 1-year rates of death and myocardial infarction were 7% (36) in the roxithromycin group and 6% (30) in the placebo group (p50.45). We showed a significant interaction between treatment and C pneumoniae antibody titre (p50.038 for restenosis, p50.006 for revascularisation), favouring roxithromycin at high titres (adjusted odds ratios at a titre of 1/512 were 0.44 [0.19-1.06] and 0.32 [0.13-0.81], respectively).

INTERPRETATION

Non-selective use of roxithromycin is inadequate for prevention of restenosis after coronary stenting. There is, however, a differential effect dependent on C pneumoniae titres. In patients with high titres, roxithromycin reduced the rate of restenosis.

Predictors of diffuse and aggressive intra-stent restenosis

OBJECTIVES

This study was performed to investigate the causes of diffuse and aggressive intra-stent restenosis.

BACKGROUND

Although restenosis is usually considered to be a dichotomous variable, there is clinical relevance to the severity of restenosis. It is not known which variables are predictive of diffuse or aggressive intra-stent restenosis.

METHODS

A consecutive series of 456 coronary lesions with in-stent restenosis was evaluated for the type of restenosis using quantitative coronary angiography. Restenosis was defined as > or = 50% diameter stenosis at follow-up angiography, diffuse restenosis as a follow-up lesion length > or = 10 mm and aggressive restenosis as either an increase in lesion length from the original lesion or a restenotic narrowing tighter than the original. Clinical, anatomic and procedural characteristics were evaluated for lesions associated with these types of restenosis.

RESULTS

Diffuse restenosis was associated with a smaller reference artery diameter, longer lesion length, female gender, longer stent length and the use of coil stents. Aggressive restenosis was more common in women, with the use of Wallstents and with long stent to lesion length ratios. Aggressive restenosis occurred earlier and was more closely associated with symptoms and myocardial infarctions than nonaggressive restenotic lesions.

CONCLUSIONS

Markers for diffuse restenosis were also important markers for the presence of any restenosis. A long stent to lesion length ratio is an important marker for aggressive restenosis. When severe forms of in-stent restenosis occur, they tend to present earlier and with more symptoms, including myocardial infarction. More careful consideration of the type of in-stent restenosis may aid in identifying when alternative strategies may be useful.

Comparison of myocardial fractional flow reserve and intravascular ultrasound for the assessment of slotted-tube stents

Intravascular ultrasound (IVUS) and myocardial fractional flow reserve (FFR) have been reported to provide similar results for assessment of coil stent deployment. Their relative value in slotted-tube stents has not been investigated. Fourteen patients subjected to coronary angioplasty and IVUS-guided elective stenting with a slotted-tube stent underwent IVUS assessment and FFR measurement following stent implantation at inflation pressures of 12 and 18 atm. FFR values (mean +/- SD) preangioplasty, postangioplasty, and poststenting at 12 atm and 18 atm, were 0.58 +/- 0.07, 0.83 +/- 0.05, 0.94 +/- 0.02, and 0.94 +/- 0.02, respectively. After inflation at 12 atm, the area under the receiver operating characteristic (ROC) curve for the concordance of IVUS and FFR measurements was 0.89 (P = 0.02). Six patients had either an abnormal IVUS (n = 2) or FFR < 0.94 (n = 1) or both abnormal IVUS and FFR < 0.94 (n = 3) after the first inflation and had a second inflation at 18 atm. The area under the ROC curve for the concordance between IVUS and FFR final measurements was 0.855 (P = 0.10). Perfect concordance between IVUS and FFR was seen only for FFR values less than 0.91 or larger than 0.94. Overall, IVUS and FFR have substantial concordance with respect to slotted-tube stent deployment. However, FFR values between 0.91 and 0.94 after inflation are difficult to interpret.

Effect of preintervention plaque burden on subsequent intimal hyperplasia in stented coronary artery lesions

We sought to determine if axial and circumferential distribution of plaque before stenting determines the axial and circumferential distribution of subsequent intimal hyperplasia (IH). We studied 22 patients with a single Palmaz-Schatz stent implanted in a native coronary artery, who underwent intravascular ultrasound (IVUS) imaging before intervention, after stenting, and at 6-month follow-up. For each lesion, 7 locations were analyzed: proximal and distal reference, proximal and distal edge of the stent, proximal and distal location within the body of the stent, and the articulation. Pre- and postintervention and follow-up image slices were precisely aligned and analyzed for pre- and postintervention plaque area and follow-up IH area and thickness. The location of maximal IH area was at or adjacent to the location of maximal preintervention plaque in 17 of 22 of the patients (77%). Similiarly, the circumferential distribution of IH at follow-up paralleled the eccentricity pattern of the native plaque burden in 69% (24 of 35 slices). Using multivariant analysis, the strongest predictor of IH was preintervention plaque area (p = 0.001). IH accumulates axially and circumferentially preferentially at the site of maximal preintervention plaque.

A prospective evaluation of angiography-guided coronary stent implantation with high versus very high balloon inflation pressure

BACKGROUND

High inflation pressure (HP) after coronary stent deployment has become a standard approach because it has been associated with a decreased subacute stent thrombosis (SAT) rate. However, the impact of HP on long-term outcomes is still unclear. We compared the long-term results of a strategy of increasing HP (>/=12 atm) until the achievement of angiographic success (<20% residual stenosis) with a prespecified very high inflation pressure (VHP) strategy of 20 atm without intermediate inflations.

METHODS AND RESULTS

We conducted a parallel-group, nonrandomized study to evaluate the short- and long-term results in 136 consecutive eligible patients who underwent successful single Palmaz-Schatz stent implantation in vessels >/=3 mm. Major adverse cardiac events (MACE), that is, death, myocardial infarction, and target lesion revascularization (TLR), were monitored for a minimum of 6 months. No significant differences were observed between the two strategies in terms of final minimal lumen diameter (HP, 3.0 +/- 0.5 vs VHP, 3. 1 +/- 0.5 mm) and acute gain (HP, 2.1 +/- 0.7 vs VHP, 2.2 +/- 0.6). The overall rate of subacute stent thrombosis was 0.7%. During a 405 +/- 148-day follow-up, 21 (28.8%) patients in the VHP group and 6 (9. 5%) in the HP group (P =.005) had MACE, with a TLR rate of 27.4% versus 7.9% (P =.009), respectively. By multivariate analysis, the use of VHP increased the odds of long-term MACE by a factor of 3.48 (P =.009). Among patients undergoing TLR, those treated with VHP had a greater lumen loss (HP, 1.83 +/- 0.57 vs VHP, 2.15 +/- 0.36 mm, P =.02) and a more frequent pattern of diffuse restenosis (71% vs 16%, P =.06).

CONCLUSIONS

In our study, the two strategies had similar acute and short-term results, but VHP was associated with a poorer long-term outcome. These data provide a rationale for a less aggressive strategy for stent deployment by optimizing rather than attempting to maximize inflation pressure and stent expansion.

Provisional stenting strategies: systematic overview and implications for clinical decision-making

Coronary stents reduce the rates of abrupt closure, emergency coronary artery bypass graft surgery and restenosis, but do not prevent myocardial infarction or death at six months. The financial burden of increased stent use and the difficulty in managing in-stent restenosis have provided the impetus to develop provisional stenting strategies. Patients at low risk for restenosis after balloon angioplasty may not derive additional benefit from stent implantation and may be successfully managed with percutaneous transluminal coronary angioplasty (PTCA) alone. Numerous patient, lesion and procedural predictors of restenosis have been identified. Postprocedural assessment using quantitative coronary angiography, intravascular ultrasound (IVUS), coronary flow velocity reserve (CVR) or fractional flow reserve (FFR) may further enhance the ability to predict adverse outcomes after PTCA. Several studies have been performed to investigate the feasibility of provisional stenting strategies using various modalities to identify low risk patients who could be managed with PTCA alone. An optimal or "stent-like" angiographic result after PTCA is associated with favorable clinical outcomes. Preliminary results of studies using IVUS or CVR to guide provisional stenting appear promising. Angiography alone may be inadequate to identify truly low risk patients and may need to be combined with clinical factors, assessment of recoil, IVUS or physiologic indexes. Strategies that avoid unnecessary stenting in even a small proportion of patients may have large impacts on health care costs. Provisional stenting may potentially reduce costs and rates of in-stent restenosis without compromising the quality of health care delivery.

A randomized comparison of elective high-pressure stenting with balloon angioplasty: six-month angiographic and two-year clinical follow-up. On behalf of AS (Angioplasty or Stent) trial investigators

BACKGROUND

Previous randomized trials have shown beneficial effects of coronary stenting on restenosis and event-free survival rates. However, it has not yet been fully established if routine high-pressure stenting with an antiplatelet regimen can show similar results.

METHODS

We compared the 6-month angiographic restenosis rate and 2-year event-free survival rate in 400 patients randomly assigned to stent or angioplasty. Aspirin and ticlopidine were prescribed in both groups.

RESULTS

The procedural success rate did not significantly differ between the stent and angioplasty groups (97.92% vs 97.45%, P = not significant). No stent thrombosis was found. The 6-month restenosis rate was lower in the stent group (18. 18% vs 24.87%, P =.055). At 2 years target lesion revascularization rate was 17.19% in the stent group and 25.51% in the angioplasty group (P =.02, 33% reduction). No significant differences with regard to death and myocardial infarction were observed. Event-free survival rate at 6, 12, and 24 months was 86.77% vs 78.84%, 84.13% vs 76.70%, and 83.07% vs 73.54% for stent and angioplasty groups, respectively (P =.0172).

CONCLUSIONS

The 6-month angiographic and 2-year clinical outcomes were better in patients who received stent than in those after balloon angioplasty. The difference in 2-year event-free survival rate was explained by a reduction in target lesion revascularization rate in the stent group.

Stent thrombosis: historical perspectives and current trends

Coronary stents are now implanted in more than 70% of percutaneous coronary revascularization procedures. Early enthusiasm for improved acute angiographic results and limited restenosis was dampened initially by a high rate of stent thrombosis and later by the increased bleeding complications of aggressive and complex anticoagulation protocols designed to lower the stent thrombosis risk. More recently, routine high-pressure deployment strategies and anti-platelet drug regimens have lowered the incidence of stent thrombosis to approximately 1% without an increased bleeding risk. The timing of stent thrombosis has also changed from a median of 4-5 days to a median of 1 day after the stent procedure. Risk factors in earlier studies included stenting for threatened or abrupt closure, smaller vessels, longer lesions, and possibly left anterior descending artery lesion location. Modern studies have shown a slightly increased risk for multiple stent use, residual dissection, and smaller final lumen. Optimal therapy for stent thrombosis includes emergent revascularization and anti-thrombotic treatment, although the clinical consequences remain dire despite successful reperfusion. The use of platelet glycoprotein IIb/IIIa inhibitors, especially in high-risk situations may further reduce the incidence of stent thrombosis.

Coronary stent symmetry and vascular injury determine experimental restenosis

OBJECTIVE

To assess the impact of stent symmetry on restenosis using the coronary overstretch sheep model.

METHODS

Neointimal thickness, injury index, and percentage diameter and area stenosis were calculated by digital morphometry. The standard deviation of the angular burden was used to assess stent symmetry for each section.

MATERIALS

15 healthy Merino sheep (63-75 kg) underwent implantation of 30 slotted tube stents (7 mm). Restenosis was induced by calculated overstretch of the coronary artery. Twenty eight days after implantation, stents were excised and underwent histological examination using quantitative digital morphometry.

RESULTS

The severity of vessel injury was positively correlated with neointimal thickness and with percentage diameter and area stenosis (p < 0.001). Mean neointimal thickness and mean vascular injury per cross section were strongly related to the standard deviation of angular burden, with correlation coefficients of 0.6 and 0.8, respectively (p < 0.001).

CONCLUSIONS

The well known relation between vascular injury and restenosis was confirmed, and a new relation was discovered between stent asymmetry and restenosis. If these results apply to human coronary arteries, restenosis may also be dependent on the degree of asymmetric stent expansion. These results should influence the development of new stent designs to reduce asymmetric stent expansion, leading to a more homogeneous strain distribution in stented coronary segments.

Long-term outcome after coronary stenting

The present review assesses the data on long-term outcome after coronary stenting. Histological, angiographical and intravascular imaging data have shown that the insertion of stents constitutes only a transient stimulus to lumen renarrowing, that this process is almost complete at 6 months and that a certain degree of neointima regression is also possible after this time. Clinical data have confirmed the sustained benefit of stenting in the long term. Careful selection of optimal stent designs and application of the recent advances in adjunctive pharmacological therapy are currently effective strategies to improve both short-and long-term results with coronary stenting. However, further efforts are needed and are ongoing to combat restenosis, a process that counters the excellent short-term results of stenting in the long term.