An optimal diagnostic threshold for minimal stent area to predict target lesion revascularization following stent implantation in native coronary lesions

Comparison of definitions of coronary artery reference sizes and effects on stent selection and evaluation of stent expansion

Accurate determination of coronary reference size is essential for optimal stent selection and evaluation of stent expansion during percutaneous coronary intervention (PCI). Several approaches for reference size estimation have been published with no universal agreement. The aim of this study was to investigate if potential differences in coronary reference size estimation lead to differences in stent and balloon selection and in detection of stent under expansion. Definitions for coronary reference size estimation, stent size selection, and stent expansion were identified in 17 randomized controlled trials. The identified methods were applied in a population of 32 clinical cases. Reference size estimates ranged up to 1.35mm, and indicated nominal stent size ranged up to 1.0 mm in the same case depending on method. Mean relative stent expansion ranged from 54±12% to mean 100±29% depending on the applied reference method. Choice of method for reference size estimation using intravascular imaging may influence stent selection and greatly affects evaluation of post-PCI stent expansion.

Combined rotational atherectomy and cutting balloon angioplasty prior to drug-eluting stent implantation in severely calcified coronary lesions: The PREPARE-CALC-COMBO study

OBJECTIVES

To evaluate the safety and efficacy of lesion preparation using rotational atherectomy (RA) with consecutive cutting balloon angioplasty (Rota-Cut).

BACKGROUND

Whether the Rota-Cut combination improves stent performance in severely calcified coronary lesions is unknown.

METHODS

PREPARE-CALC-COMBO is a single-arm prospective trial in which 110 patients were treated with a Rota-Cut strategy before implantation of sirolimus-eluting stents and compared with patients treated with modified balloon (MB, scoring or cutting) or RA from a historical cohort (the randomized PREPARE-CALC trial). The study had two primary endpoints: in-stent acute lumen gain (ALG) by quantitative angiographic analysis and stent expansion (SE) on optical coherence tomography.

RESULTS

In-stent ALG was significantly higher with Rota-Cut compared to RA or MB alone (1.92 ± 0.45 mm vs. 1.74 ± 0.45 mm with MB vs. 1.70 ± 0.42 mm with RA; p = 0.001 and p < 0.001, respectively). SE was comparable between groups (75.1 ± 13.8% vs. 73.5 ± 13.3 with MB vs. 73.1 ± 12.2 with RA; p = 0.19 and p = 0.39, respectively). The Rota-Cut combination resulted in higher minimal stent area (MSA) (7.1 ± 2.2mm² vs. 6.1 ± 1.7mm²  with MB vs. 6.2 ± 1.9mm² with RA; p = 0.003 and p = 0.004, respectively). In-hospital death occurred in one patient. Target vessel failure at 9 months was low and comparable between groups (8.2% vs. 8% with MB vs. 6% with RA; p = 1 and p = 0.79, respectively).

CONCLUSION

Rota-Cut combination resulted in higher ALG and larger MSA compared with historical control of RA or MB alone, but was not associated with higher SE. Despite extensive lesion preparation, this strategy is safe, feasible, and associated with favorable clinical outcome at 9 months.

In-Stent Restenosis

In-stent restenosis (ISR) remains a potential complication after percutaneous coronary intervention, even in the era of drug-eluting stents, and its treatment remains suboptimal. Neoatherosclerosis is an important component of the pathology of ISR and is accelerated in drug-eluting stents compared with bare-metal stents. Coronary angiography is the gold standard for evaluating the morphology of ISR, although computed tomography angiography is emerging as an alternative noninvasive modality to evaluate the presence of ISR. Drug-coated balloons and stent reimplantation are the current mainstays of treatment for ISR, and the choice of treatment should be based on clinical background and lesion morphology.

Optical Coherence Tomography: An Eye Into the Coronary Artery

Optical coherence tomography (OCT) is slowly but surely gaining a foothold in the hands of interventional cardiologists. Intraluminal and transmural contents of the coronary arteries are no longer elusive to the cardiologist's probing eye. Although the graduation of an interventionalist in imaging techniques right from naked eye angiographies to ultrasound-based coronary sonographies to the modern light-based OCT has been slow, with the increasing regularity of complex coronary cases in practice, such a transition is inevitable. Although intravascular ultrasound (IVUS) due to its robust clinical data has been the preferred imaging modality in recent years, OCT provides a distinct upgrade over it in many imaging and procedural aspects. Better image resolution, accurate estimation of the calcified lesion, and better evaluation of acute and chronic stent failure are the distinct advantages of OCT over IVUS. Despite the obvious imaging advantages of OCT, its clinical impact remains subdued. However, upcoming newer trials and data have been encouraging for expanding the use of OCT to wider indications in clinical utility. During percutaneous coronary intervention (PCI), OCT provides the detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition) required for optimal stent deployment, which is the key to successfully reducing the major adverse cardiovascular event (MACE) and stent-related morbidities. The increasing use of OCT in complex bifurcation stenting involving the left main (LM) is being studied. Also, the traditional pitfalls of OCT, such as additional contrast load for image acquisition and stenting involving the ostial and proximal LM, have also been overcome recently. In this review, we discuss the interpretation of OCT images and its clinical impact on the outcome of procedures along with current barriers to its use and newer paradigms in which OCT is starting to become a promising tool for the interventionalist and what can be expected for the immediate future in the imaging world.

Predictors of Irregular Protrusion After Everolimus-Eluting Stent Implantation in Patients with Stable Coronary Artery Disease

This study aimed to investigate clinical and preintervention optical coherence tomography (OCT) findings to predict irregular protrusion (IRP) immediately after stent implantation.We evaluated 84 lesions treated with cobalt-chromium everolimus-eluting stent (CoCr-EES) from the MECHANISM Elective study. Patients were divided into two groups according to the presence of IRP [IRP: n = 16, non-IRP: n = 68]. Optical coherence tomography images before intervention and immediately after stenting were evaluated with standard qualitative and quantitative OCT analyses.Total cholesterol and the prevalence of ruptured plaque before intervention were significantly higher in the IRP group than in the non-IRP group [199 ± 37 mg/dL versus 176 ± 41 mg/dL; P = 0.022, 31% versus 7%; P = 0.008]. Total lipid length tended to be longer in the IRP group than in the non-IRP group [19.6 ± 9.2 mm versus 15.5 ± 9.3 mm; P = 0.090]. The prevalence of ruptured plaque, and total cholesterol levels were independent predictors of IRP immediately after stenting by multivariate logistic regression analysis [OR: 4.6, 95% confidence interval: 1.01-21.23, P = 0.048, OR: 1.02, 95% confidence interval: 1.00-1.03, P = 0.046]. IRP post-CoCr-EES implantation was completely resolved at follow-up OCT.The prevalence of ruptured plaque before intervention and total cholesterol levels were independent predictors of IRP after CoCr-EES implantation in patients with stable coronary artery disease.

Optical Coherence Tomography of the Coronary Arteries

Intravascular imaging, particularly optical coherence tomography, has brought significant improvement in diagnostic and therapeutical approaches to coronary artery disease and has offered superior high-resolution visualization of coronary arteries. The ability to obtain images of intramural and transmural coronary structures allows the study of the process of atherosclerosis, effect of therapies, mechanism of acute coronary syndrome and stent failure, and performance of new devices and enables the interventional cardiologist to optimize the effect of percutaneous coronary intervention. In this review, we provide the summary of the latest published data on clinical use of optical coherence tomography as well as practical algorithm for optical coherence tomography-guided percutaneous coronary intervention for daily interventional practice.

Impact of optical coherence tomography findings on clinical outcomes in ST-segment elevation myocardial infarction patients: a MATRIX (Minimizing Adverse Hemorrhagic Events by Trans-radial Access Site and angioX) OCT sub-study

PURPOSE

To investigate the association of the degree of stent expansion, as assessed by optical coherence tomography (OCT), following stent implantation, and clinical outcomes in ST-segment elevation myocardial infarction (STEMI) patients.

METHODS

STEMI patients from the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) OCT study were selected; Clinical outcomes were collected through 1 year. Stent expansion index is a minimum stent area (MSA) divided by average lumen area (average of proximal and distal reference lumen area). The following variables were measured: MSA (< 4.5mm²), dissection (> 200 µm in width and < 5 mm from stent segment), malapposition (> 200 µm distance of stent from vessel wall), a thrombus (area > 5% of lumen area) were compared.

RESULTS

A total of 151 patients were included; after excluding patients with suboptimal OCT quality, the population with available OCT was classified into 2 groups: under-expanded < 90% (N = 72, 51%) and well-expanded ≥ 90% (N = 67, 49%). In the well-expanded group, a significant number of the proximal vessels had a lumen area < 4.5mm² (16.1%, p < 0.001) and a greater thrombus burden within stent (56.7%, p = 0.042). The overall 30 day and 1 year major adverse cardiovascular event (MACE) rates were 5% and 6.1%, respectively.

CONCLUSION

Irrespective of the degree of stent expansion, the OCT findings, in STEMI patients, and the MACE at 30 days and one year follow up was low; further, well-expanded stents led to a more significant residual thrombotic burden within the stent but seemed to have insignificant clinical impact. Acknowledged stent optimization criteria, traditionally related to worse outcomes in stable patients, do not seem to be associated with worse outcomes in this STEMI population.

Personalized Assessment of the Coronary Atherosclerotic Arteries by Intravascular Ultrasound Imaging: Hunting the Vulnerable Plaque

The term “vulnerable plaque” is commonly used to refer to an atherosclerotic plaque that is prone to rupture and the formation of thrombosis, which can lead to several cardiovascular and cerebrovascular events. Coronary artery atherosclerosis has a wide variety of different phenotypes among patients who may have a substantially variable risk for plaque rupture and cardiovascular events. Mounting evidence has proposed three distinctive histopathological mechanisms: plaque rupture, plaque erosion and calcified nodules. Studies have demonstrated the characteristics of plaques with high vulnerability such as the presence of a thin fibrous cap, a necrotic lipid-rich core, abundant infiltrating macrophages and neovascularization. However, traditional coronary angiographic imaging fails to determine plaque vulnerability features, and its ability to individualize treatment strategies is limited. In recent decades, catheter-based intravascular ultrasound imaging (IVUS) modalities have been developed to identify vulnerable plaques and ultimately vulnerable patients. The aim is to individualize prediction, prevention and treatment of acute coronary events based on the identification of specific features of high-risk atherosclerotic plaques, and to identify the most appropriate interventional procedures for their treatment. In this context, the aim of this review is to discuss how personalized assessment of coronary atherosclerotic arteries can be achieved by intravascular ultrasound imaging focusing on vulnerable plaque detection.

Optimization of Percutaneous Coronary Intervention Using Optical Coherence Tomography

Compared to the luminogram obtained by angiography, intravascular modalities produce cross-sectional images of coronary arteries with a far greater spatial resolution. It is capable of accurately determining the vessel size and plaque morphology. It also eliminates some disadvantages such as contrast streaming, foreshortening, vessel overlap, and angle dependency inherent to angiography. Currently, the development of its system and the visualization of coronary arteries has shown significant advancement. Of those, optical coherence tomography (OCT) makes it possible to obtain high-resolution images of intraluminal and transmural coronary structures leading to navigation of the treatment strategy before and after stent implantations. The aim of this review is to summarize the published data on the clinical utility of OCT, focusing on the use of OCT in interventional cardiology practice to optimize percutaneous coronary intervention.

The Value of Pre- and Post-Stenting Fractional Flow Reserve for Predicting Mid-Term Stent Restenosis Following Percutaneous Coronary Intervention (PCI)

Measuring fractional flow reserve (FFR) in percutaneous coronary intervention (PCI) has predictive value for PCI outcome. We decided to examine the utility of pre- and post-stenting FFR as a predictor of 6-month stent restenosis as well as MACE (major adverse cardiac events). Pre- and post-stenting FFR values were measured for 60 PCI patients. Within 6 months after stenting, all patients were followed for assessment of cardiac MACE including myocardial infarction, unstable angina, or positive exercise test. Stent restenosis was also assessed. Cut-off values for pre- and post-stenting FFR measurements were considered respectively as 0.65 and 0.92. Stent restenosis was detected in 4 patients (6.6%). All 4 patients (100%) with restenosis had pre-stenting FFR of < 0.65, while only 26 of 56 patients without restenosis (46.4%) had pre-stenting FFR value of < 0.65 (P = 0.039). Mean pre-stenting FFR in patients with restenosis was significantly lower than in those without restenosis (0.25 ± 0.01 vs. 0.53 ± 0.03, P = 0.022). Although stent restenosis was higher in patients with post-stenting FFR of < 0.92 (2 cases, 9.5%) than in those with FFR value of ≥ 0.92 (2 cases, 5.1%), the difference was not statistically (P = 0.510). Pre-stenting FFR, the use of longer stents, and history of diabetes mellitus can predict stent restenosis, but the value of post-stenting FFR for predicting restenosis was not explicit.

Incidence and Clinical Significance of Poststent Optical Coherence Tomography Findings

Background—

Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown.

Methods and Results—

A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel–related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm 2 in a drug-eluting stent or <5.6 mm 2 in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points ( P =0.003 and P =0.012, respectively).

Conclusions—

Abnormal poststent OCT findings were frequent. Irregular protrusion and small minimal stent area were independent predictors of 1-year device-oriented clinical end points, which were primarily driven by target lesion revascularization.

Clinical utility of intravascular imaging and physiology in coronary artery disease

Intravascular imaging and physiology techniques and technologies are moving beyond the framework of research to inform clinical decision making. Currently available technologies and techniques include fractional flow reserve; grayscale intravascular ultrasound (IVUS); IVUS radiofrequency tissue characterization; optical coherence tomography, the light analogue of IVUS; and near-infrared spectroscopy that detects lipid within the vessel wall and that has recently been combined with grayscale IVUS in a single catheter as the first combined imaging device. These tools can be used to answer questions that occur during daily practice, including: Is this stenosis significant? Where is the culprit lesion? Is this a vulnerable plaque? What is the likelihood of distal embolization or periprocedural myocardial infarction during stent implantation? How do I optimize acute stent results? Why did thrombosis or restenosis occur in this stent? One of the legacies of coronary angiography is to presume that one technique will answer all of these questions; however, that often has been proved inaccurate in contemporary practice.

Utility of myocardial fractional flow reserve for prediction of restenosis following sirolimus-eluting stent implantation

Drug-eluting stents reduce restenosis due to neointimal growth suppression. Considering long-term outcomes, it is both difficult and important to predict drug-eluting stent restenosis. Thus, this study was designed to examine the utility of myocardial fractional flow reserve (FFR) as a predictor of sirolimus-eluting stent (SES) restenosis. Thirty-three patients (35 lesions) were enrolled. Upon completion of SES implantation, FFR was obtained under hyperemia. At 8 months of follow-up, coronary angiography revealed that five lesions had restenosis. Percent diameter stenosis (restenosis 68.7 ± 12.8% vs. non-restenosis 68.7 ± 12.4%, p = 0.78) and lesion length (restenosis 15.8 ± 9.4 mm vs. non-restenosis 14.4 ± 9.2 mm, p = 0.60) were similar. At post-intervention, percent diameter stenosis (restenosis 16.4 ± 6.1% vs. non-restenosis 14.0 ± 7.4%, p = 0.48) and minimum stent area (restenosis 6.01 ± 1.08 mm2 vs. non-restenosis 6.27 ± 1.85 mm2, p = 0.92) were also equivalent. However, proximal edge lumen area was smaller (restenosis 4.24 ± 1.40 mm2 vs. non-restenosis 7.73 ± 2.64 mm2, p = 0.004) and FFR was lower in the restenosis group (restenosis 0.81 ± 0.12 vs. non-restenosis 0.92 ± 0.06, p = 0.029). SES patients with restenosis had a lower FFR post stent deployment, suggesting the decreased FFR may be a useful predictor for SES restenosis.

Predictors of restenosis after percutaneous coronary intervention using bare-metal stents: a comparison between patients with and without dysglycemia

The objective of this study was to identify intravascular ultrasound (IVUS), angiographic and metabolic parameters related to restenosis in patients with dysglycemia. Seventy consecutive patients (77 lesions) selected according to inclusion and exclusion criteria were evaluated by the oral glucose tolerance test and the determination of insulinemia after a successful percutaneous coronary intervention (PCI) with a bare-metal stent. The degree of insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR). Six-month IVUS and angiogram follow-up were performed. Thirty-nine patients (55.7%) had dysglycemia. The restenosis rate in the dysglycemic group was 37.2 vs 23.5% in the euglycemic group (P = 0.299). The predictors of restenosis using bivariate analysis were reference vessel diameter (RVD): pound2.93 mm (RR = 0.54; 95%CI = 0.05-0.78; P = 0.048), stent area (SA): <8.91 mm(2) (RR = 0.66; 95%CI = 0.24-0.85; P = 0.006), stent volume (SV): <119.75 mm(3) (RR = 0.74; 95%CI = 0.38-0.89; P = 0.0005), HOMA-IR: >2.063 (RR = 0.44; 95%CI = 0.14-0.64; P = 0.027), and fasting plasma glucose (FPG): < or =108.8 mg/dL (RR = 0.53; 95%CI = 0.13-0.75; P = 0.046). SV was an independent predictor of restenosis by multivariable analysis. Dysglycemia is a common clinical condition in patients submitted to PCI. The degree of insulin resistance, FPG, RVD, SA, and SV were correlated with restenosis. SV was inversely correlated with an independent predictor of restenosis in patients treated with a bare-metal stent.

Impact of post-intervention minimal stent area on 9-month follow-up patency of paclitaxel-eluting stents: an integrated intravascular ultrasound analysis from the TAXUS IV, V, and VI and TAXUS ATLAS Workhorse, Long Lesion, and Direct Stent Trials

OBJECTIVES

We investigated the predictive value of the intravascular ultrasound (IVUS) measured post-intervention minimum stent area (MSA) on 9-month follow-up paclitaxel-eluting stent (PES) patency compared with bare-metal stents (BMS).

BACKGROUND

Stent underexpansion is a strong predictor for restenosis after sirolimus-eluting stent implantation, but the implication of underexpansion in PES is still unknown.

METHODS

From the combined TAXUS IV, V, and VI and TAXUS ATLAS Workhorse, Long Lesion, and Direct Stent trials, 1,580 patients (PES 1,098, BMS 482) in IVUS substudies were analyzed. The MSA that best predicted angiographic in-stent restenosis (ISR) (% diameter stenosis > or =50%) was determined.

RESULTS

The post-intervention IVUS MSA was similar in PES and BMS (6.6 +/- 2.5 mm(2) vs. 6.7 +/- 2.3 mm(2), p = 0.92). At 9-month follow-up, ISR was lower in the PES group versus the BMS group (10% vs. 31%, p < 0.0001). Using multivariable logistic regression analysis, post-intervention IVUS MSA was the independent predictor of subsequent ISR in both the PES and BMS groups (p = 0.0002 for PES and p = 0.0002 for BMS). The ability of the post-intervention IVUS MSA to predict ISR was further assessed using receiver operating characteristic analysis. The post-intervention IVUS MSA was found to be a faithful discriminator between patients with and without ISR in both PES (c = 0.6382) and BMS (c = 0.6373). Finally, the optimal thresholds of post-intervention IVUS MSA that best predicted stent patency at 9 months were 5.7 mm(2) for PES and 6.4 mm(2) for BMS.

CONCLUSIONS

Post-intervention MSA measured by IVUS can predict 9-month follow-up stent patency after both PES and BMS implantation. (Randomized Trial Evaluating Slow-Release Formulation TAXUS Paclitaxel-Eluting Coronary Stents to Treat De Novo Coronary Lesions; NCT00301522) (Direct Stenting of TAXUS Liberté-SR Stent for the Treatment of Patients With de Novo Coronary Artery Lesions; NCT00371423) (A Study of the TAXUS Liberté Stent for the Treatment of Long De Novo Coronary Artery Lesions; NCT00371475) (A Study of the TAXUS Liberté Stent for the Treatment of de Novo Coronary Artery Lesions in Small Vessels; NCT00371748).

Intravascular ultrasound evaluation of optimal drug-eluting stent expansion after poststent balloon dilation using a noncompliant balloon versus a semicompliant balloon (from the Poststent Optimal Stent Expansion Trial [POET])

The impact of type of balloon such as noncompliant (NC; Quantum) or semicompliant (SC; Maverick(2)) used after stent dilation on optimal stent expansion (OSE) has not been established for drug-eluting stents (DESs). We conducted a prospective multicenter, randomized study to compare NC with SC balloons after stent balloon dilatation. A total of 301 patients (127 men, 83 women, 62 +/- 9 years of age) treated with a DES (sirolimus-eluting stent [SES], n = 152; paclitaxel-eluting stent, n = 149) were included. OSE followed the definition of the Multicenter Ultrasound Stenting in Coronaries (MUSIC) study. The primary end point was the incidence of OSE using intravascular ultrasound according to type of balloon. Baseline characteristics of each group showed no significant differences. OSE in the SC balloon group was achieved at higher rates than the NC balloon group (53 +/- 35%, vs 73 +/- 48%, p = 0.022 in all stents; 25 +/- 33%, vs 36, 48%, p = 0.051 in SESs). However, any differences in the achievement of OSE between the NC and SC balloon groups were not present in paclitaxel-eluting stents. In conclusion, despite postadjuvant balloon inflations with high pressures, underexpansion of the DES was seen commonly. Between the 2 types of balloon for adjuvant dilation after DES implantation, same-size SC balloons could be more useful for obtaining OSE than NC balloons, especially in SESs.

Duration of development of symptomatic in-stent restenosis correlates with the stent-to-vessel-diameter ratio: an intravascular ultrasound study

OBJECTIVE

Several predictors for in-stent restenosis (ISR) have been defined by intravascular ultrasound (IVUS) assessment; however, there is a lack of data correlating IVUS parameters with the speed of development of ISR. This study aims to investigate the relation between the duration of development of symptomatic ISR and the relative stent diameter.

METHODS

A total of 46 lesions in 43 consecutive patients with symptomatic ISR were investigated by IVUS with the Endosonics system (Volcano Therapeutics Inc., Rancho Cardova, California, USA). Duration of development of symptomatic ISR was determined by the period of angiographic evidence for ISR. Early ISR was defined in case of occurrence before 6 months. Reference vessel diameter was assessed as mean diameter limited by the external elastic membrane. Relative stent diameter was defined by the stent-to-vessel-diameter ratio (SVDR).

RESULTS

Mean duration of symptomatic ISR was 10.3+/-11.5 months for all 46 lesions. Early ISR was observed in 25 lesions (54%). Multivariate analysis revealed SVDR as the only independent predictor for early ISR (P=0.0242). Significant correlation was observed between the duration of development of symptomatic ISR and SVDR (r=0.634, P<0.001). On the basis of the receiver operating curve analysis, relative stent diameter was defined as small when SVDR< or =0.90. Symptomatic ISR within stents of small relative diameter occurred significantly earlier (5.3+/-3.0 versus 16.7+/-15.0 months, P<0.001) and more frequently before 6 months (73 versus 30%, P=0.003) than in stents with SVDR>0.90.

CONCLUSIONS

This IVUS study revealed significant correlation between the duration of development of symptomatic ISR and SVDR, which was an independent predictor for early ISR. IVUS-guided stenting may avoid early ISR by adapting the stent diameter to the vessel diameter.

Clinical and angiographic follow-up after coronary drug-eluting and bare metal stent implantation. Do drug-eluting stents hold the promise?

OBJECTIVES

To investigate the influence of drug-eluting stent (DES) implantation on clinical and angiographic restenosis.

DESIGN

Registry study of data from the Swedish Coronary Angiography and Angioplasty Registry with a coronary angiographic substudy.

SETTING

Multi-centre study.

SUBJECTS

During October 2002 to May 2004 a total of 23 590 percutaneous coronary intervention (PCI) procedures were performed at 25 hospitals. After selection, to achieve comparable groups, a total of 5068 patients of whom 4111 had a bare metal stent (BMS) implanted and 957 had a DES implanted, remained. End-point in the registry follow-up was >50% diameter restenosis at clinically driven reangiography within 12 months after index PCI. The primary end-point in the angiographic substudy was late loss in patients' DES at 6-month angiographic follow-up.

RESULTS

The rate of clinically driven restenosis, within 12 months, in patients receiving DES was less (3.9%) compared with those who received BMS (7.0%). In multivariate analysis the risk of clinical restenosis was one-third for DES compared with BMS (HR 0.36, 95% CI 0.25-0.52). In the angiographic substudy late loss was 0.07+/-0.53 mm (range -0.88 to 1.62). The amount of late loss was related to the presence of diabetes mellitus or not (0.19+/-0.45 mm vs. -0.12+/-0.58 mm), and lack of postdilatation of the stent or not (0.23+/-0.51 mm vs. -0.09+/-0.50 mm).

CONCLUSIONS

The use of DES in the Swedish 'real world' is effective in reducing the clinically driven restenosis rate, when compared with patients with BMS treatment. In the angiographic follow-up the average late loss was as low as observed in recent randomized multi-centre trials.

Impact of Angiotensin II Receptor Blockers on the Progression and Regression of Coronary Atherosclerosis An Intravascular Ultrasound Study

BACKGROUND

Although angiotensin II receptor blockers (ARB) have been found to reduce the coronary atherosclerotic plaque burden in animal models, it is unknown whether ARB have a similar effect on human coronary arteries.

METHODS AND RESULTS

Serial intravascular ultrasound (IVUS) studies of the left main (LM) coronary artery were performed in 64 patients at baseline and after 7-month follow-up. All patients were divided into 2 groups (ARB group: 23 patients; non-ARB group: 41 patients). Three-dimensional volumetric analysis was done throughout the LM coronary artery, and the volume index (VI; volume/length) was calculated for the vessel (VVI), lumen (LVI), and plaque (PVI). No significant difference was found between the 2 groups in baseline clinical characteristics, including age, gender, blood pressure levels, serum cholesterol levels, the presence of diabetes and smoking status. At baseline VVI, LVI and PVI were similar between the groups. In the non-ARB group, VVI, LVI, and PVI did not change between baseline and follow-up. In the ARB group, PVI significantly decreased during follow-up (9.9 +/-3.1 mm2 vs 9.1+/-2.7 mm2, p<0.01), whereas VVI and LVI were unaffected.

CONCLUSIONS

This preliminary IVUS study suggests that ARB could cause regression of coronary atherosclerosis in humans.

Incidence of stent under-deployment as a cause of in-stent restenosis in long stents

Although stent under-deployment (SU) has been associated with increased risk of in-stent restenosis, little data have been reported on the incidence of SU in patients presenting with clinical in-stent restenosis. In 59 patients referred for vascular brachytherapy and showing angiographic in-stent restenosis, we sought (1) to determine the incidence of SU using standard intravascular ultrasound (IVUS) criteria (2) to evaluate the effects of repeat angioplasty on further stent expansion. Stented length was 32+/-17 mm and diameter stenosis was 75+/-14%. Before re-intervention, the incidence of reduced absolute values of minimal stent cross-sectional area (MSCSA) varied from 69% (< or =8 mm2) to 15% (< or =5 mm2). After re-intervention, the incidence decreased to 24% (< or =8 mm2) (p = 0.0001) and 0% (< or =5 mm2) (p = 0.005). Before re-intervention, SU as assessed by relative criteria varied from 21% (80% mean reference lumen area or 90% minimum distal reference lumen area) to 28% (100% minimum reference lumen area). After re-intervention, the incidence of SU varied from 7% (90% minimum distal reference lumen area) (p = 0.0001 vs. pre) to 24% (55% mean reference EEM area) (p = ns). No change in strut apposition (97% pre vs. 100% post) nor in symmetry index (100% pre vs. post) was noted. From all criteria, the 90 and 100% minimum reference lumen area criteria were the most altered by repeat balloon dilatation, 21% pre vs. 7% post and 28% pre vs. 11% post, respectively. In conclusion, among patients presenting with severe angiographic in-stent restenosis, a significant number showed signs of SU whose incidence varied according to applied criteria. Significant stent re-expansion can be obtained following IVUS-guided repeat angioplasty irrespective of initial SU criteria.

Is overdilatation of 3.0 mm sirolimus-eluting stent associated with a higher restenosis rate?

We evaluated the safety and effectiveness of postdilating a 3.0 mm sirolimus-eluting stents (SESs; six cells) with a 3.5-4.0 mm balloon. We identified 254 consecutive patients who underwent percutaneous coronary interventions using SESs with a nominal diameter of 3.0 mm (six cells). Patients were divided into two groups based on whether they were subsequently postdilated with a 3.0 mm (group 1: 168 patients, 251 lesions) or a 3.5-4 mm balloon (group 2: 86 patients, 102 lesions). There were no significant differences regarding the incidence of in-hospital and long-term follow-up. Angiographic follow-up was available in 72% and 74% of groups 1 and 2, respectively. The two groups had no significant differences regarding late lumen loss (0.51 +/- 0.36 vs. 0.52 +/- 0.33; P = 0.3) and binary restenosis rates (10.7% vs. 8.8%; P = 0.1). Six-month clinical follow-up was available in all patients. At long-term follow-up (mean: 10.6 +/- 3.7 for group 1 and 11.3 +/- 3.9 months for group 2), there were no significant differences between the two groups regarding major adverse cardiac events (8.9% vs. 9.2%; P = 0.9). Implantation of a 3.0 mm SES with postdilation with a 3.5-4 mm balloon did not result in any significant difference in complications, in-hospital non-Q-wave myocardial infarction, binary restenosis, or target lesion revascularization. These data should lessen concern that overdilation may dilute the beneficial effects of SESs.

Impact of final stent dimensions on long-term results following sirolimus-eluting stent implantation: serial intravascular ultrasound analysis from the sirius trial

OBJECTIVES

We assessed the predictive value of minimum stent area (MSA) for long-term patency of sirolimus-eluting stents (SES) implantation compared to bare metal stents (BMS).

BACKGROUND

Although MSA is a consistent predictor of in-stent restenosis, its predictive value in BMS is still limited because of biologic variability in the restenosis process.

METHODS

From the SIRolImUS (SIRIUS) trial, 122 cases (SES: 72; BMS: 50) with complete serial intravascular ultrasound (IVUS) (baseline and 8-month follow-up) were analyzed. Postprocedure MSA and follow-up minimum lumen area (MLA) were obtained. Based on previous physiologic studies, adequate stent patency at follow-up was defined as MLA >4 mm(2).

RESULTS

In both groups, a significant positive correlation was observed between baseline MSA and follow-up MLA (SES: p < 0.0001, BMS: p < 0.0001). However, SES showed higher correlation than BMS (0.8 vs. 0.65) with a higher regression coefficient (0.92 vs. 0.59). The sensitivity and specificity curves identified different optimal thresholds of MSA to predict adequate follow-up MLA: 5 mm(2) for SES and 6.5 mm(2) for BMS. The positive predictive values with these cutoff points were 90% and 56%, respectively.

CONCLUSIONS

In this SIRIUS IVUS substudy, SES reduced both biologic variability and restenosis, resulting in increased predictability of long-term stent patency with postprocedure MSA. In addition, SES had a considerably lower optimal MSA threshold compared to BMS.

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.

Optimal final lumen area and predictors of target lesion revascularization after stent implantation in small coronary arteries

Despite similar early clinical events, patients who undergo treatment of small vessels are at an increased risk for target lesion revascularization (TLR) after coronary artery stenting. We sought to determine predictors of TLR after stent implantation in small coronary arteries. We identified 423 consecutive patients who underwent intravascular ultrasound (IVUS)-guided small vessel stenting procedures in 465 coronary lesions with an angiographic reference vessel diameter of <2.75 mm. Patients were divided into 2 groups based on a final IVUS lumen area of < or =6.0 mm2 (n=345 lesions, group I) and >6.0 mm2 (n=115, group II). Baseline patient characteristics and in-hospital outcomes were similar between the 2 groups, except for a higher rate of restenotic lesions in group I and bifurcation lesions in group II. Group I had higher TLR rates at 1 year compared with group II patients (39% vs 26%, p = 0.02). The TLR rate appeared to decrease with greater stent expansion, especially at >90% of the reference vessel area, as assessed by IVUS. By multivariate analysis, an IVUS final stent area of < or =6 mm2, diabetes, absence of prior myocardial infarction, and history of intervention were independent predictors of 1-year TLR in this population. Final stent area of >6.0 mm2 and greater stent expansion were associated with a decrease in TLR. Therefore, there does not appear to be any "downside" to aggressive stent implantation strategies in small vessels. In contrast, IVUS allows maximization of final lumen dimensions to minimize clinical restenosis.

Impact of the acute results on the long-term outcome after the treatment of in-stent restenosis: A serial intravascular ultrasound study

The current study used serial (postintervention and follow-up) intravascular ultrasound (IVUS) to assess the impact of acute results on long-term follow-up of patients with in-stent restenosis (ISR). All patients (n = 180) with serial IVUS studies of ISR lesions from the following gamma-irradiation brachytherapy trials were included: Washington Radiation for In-Stent Restenosis Trial (WRIST), Gamma-1, and Angiorad Radiation Technology for In-Stent Restenosis Trial in Native Coronaries (ARTISTIC). There were 106 irradiated and 74 placebo patients. Quantitative analysis was performed according to the American College of Cardiology Clinical Expert Consensus Document on Standards for Acquisition, Measurement and Reporting of IVUS. Images were acquired using motorized transducer pullback, cross-sectional analysis was performed every 1 mm, and volumetric and mean planar dimensions were calculated. The independent predictors for the absolute follow-up minimum lumen area (MLA) were the postintervention MLA, the postintervention minimum stent area, and the use of brachytherapy. Placebo patients lost 45% of the postintervention MLA while irradiated patients lost only 17% of the MLA. The independent predictors of the follow-up percent intimal hyperplasia (intimal hyperplasia volume divided by stent volume) and the independent predictors of the absolute increase in intimal hyperplasia were the postintervention percent intimal hyperplasia and the use of brachytherapy. Serial IVUS analysis shows that the follow-up MLA and percent intimal hyperplasia are dependent on the results obtained during the treatment of ISR lesions.

Relationship between neointimal regrowth and mechanism of acute lumen gain during the treatment of in-stent restenosis with or without supplementary intravascular radiation

We investigated whether neointimal regrowth is related to the mechanism of acute lumen gain during the treatment of in-stent restenosis (ISR) lesions both with and without adjunct intravascular brachytherapy. From the WRIST (Washington Radiation for In-Stent Restenosis Trial) cohort, 54 ISR patients ((192)Ir, 29; placebo, 25) were treated with nonrepeat stenting percutaneous interventions (excimer laser, rotational atherectomy, and/or balloon angioplasty) prior to (192)Ir or placebo therapy. Using Simpson's method, serial volumetric intravascular ultrasound (IVUS) analyses (pre- and posttreatment and 6-month follow-up) were analyzed to obtain stent, lumen, and intimal hyperplasia (IH) volumes that were then adjusted for stent length to create stent, lumen, and IH volume indexes. In the placebo group, the acute reduction of neointima (1.6 +/- 1.4 mm(3)/mm) was counteracted by intimal regrowth (2.1 +/- 1.7 mm(3)/mm). The amount of intimal regrowth correlated directly with the intimal reduction due to the intervention (r = 0.76; P < 0.001), but not with the amount of additional stent expansion. In the (192)Ir-treated group, intimal regrowth was significantly less than in the placebo group (-0.3 +/- 0.1 vs. 2.1 +/- 1.7 mm(3)/mm; P < 0.001) despite a similar initial intimal reduction (1.3 +/- 0.9 vs. 1.6 +/- 1.4 mm(3)/mm; P = NS). No correlation was found between intimal reduction at the time of the procedure and intimal regrowth in the (192)Ir group. In this study, neointimal regrowth following treatment of ISR lesions correlates directly with the extent of acute intimal volume reduction, but not with the extent of additional stent expansion. This relation is not seen in ISR segments treated with radiation, where intimal regrowth is substantially inhibited.