Percutaneous coronary intervention in patients undergoing transcatheter aortic valve implantation: a systematic review and meta-analysis.

OBJECTIVE: The importance of revascularisation of significant coronary artery disease (CAD) in patients undergoing transcatheter aortic valve implantation (TAVI) is unclear. Despite the lack of randomised controlled trials comparing different revascularisation strategies, guidelines currently recommend percutaneous coronary intervention (PCI) in patients with significant proximal CAD undergoing TAVI. METHODS: In this systematic review and meta-analysis, a systematic search was conducted to identify studies comparing TAVI with and without PCI in patients with significant CAD on pre-TAVI coronary angiography. Endpoints were all-cause mortality, cardiac death, stroke, myocardial infarction and major bleeding. RESULTS: In total, 14 studies were included, involving 3838 patients, of whom 1806 (47%) underwent PCI before TAVI. All-cause mortality did not differ significantly between TAVI with and without preceding PCI at 30 days, 1 year and > 1 year. There were no significant differences in risk of cardiac death, stroke or myocardial infarction between the groups. However, TAVI performed with PCI resulted in a higher risk of major bleeding within 30 days after TAVI (odds ratio: 0.66; 95% confidence interval: 0.46-0.94). CONCLUSION: This systematic review and meta-analysis showed no significant differences in clinical outcomes between patients with concomitant significant CAD who were treated with TAVI with and without preceding PCI at both short- and long-term follow-up. However, there was a higher risk of major bleeding at 30 days in patients undergoing TAVI with preceding PCI. In the context of serious risk of bias in the included studies, results of randomised controlled trials are warranted.

Predictors and outcomes of procedural failure of percutaneous coronary intervention of a chronic total occlusion-A subanalysis of the EXPLORE trial.

OBJECTIVE: To evaluate predictors of procedural success of percutaneous coronary intervention (PCI) of chronic total coronary occlusions (CTOs) in a non-infarct-related artery following ST-segment elevation myocardial infarction (STEMI), and demonstrate the effect on left ventricular functionality (LVF), infarct size (IS), and pro-arrhythmic electrocardiogram (ECG) parameters. BACKGROUND: Predictors of unsuccessful revascularization of a CTO are numerous, although following STEMI, these are lacking. Besides, effects of failed CTO PCI (FPCI) on the myocardium are unknown. METHODS: This is a subanalysis of the EXPLORE trial, in which 302 STEMI patients with a concurrent CTO were randomized to CTO PCI (n = 147) or no-CTO PCI (NPCI, n = 154). For the purpose of this subanalysis, we divided patients into successful CTO PCI (SPCI, n = 106), FPCI (n = 41), and NPCI (n = 154) groups. Cardiac magnetic resonance imaging and angiographic data were derived from the EXPLORE database, combined with ECG parameters. To gain more insight, all outcomes were compared with patients that did not undergo CTO PCI. RESULTS: In multivariate regression, only CTO lesion length >20 mm was an independent predictor of procedural failure (OR 3.31 [1.49-7.39]). No significant differences in median left ventricular ejection fraction, left ventricular end-diastolic volume, IS, and the pro-arrhythmic ECG parameters such as QT-dispersion, QTc-time, and TpTe-intervals were seen between the SPCI and FPCI groups at 4 months follow-up. CONCLUSION: This subanalysis of the EXPLORE trial has demonstrated that a CTO lesion length >20 mm is an independent predictor of CTO PCI failure, whereas procedural failure did not lead to any adverse effects on LVF nor pro-arrhythmic ECG parameters.

Aspirin with or without Clopidogrel after Transcatheter Aortic-Valve Implantation.

BACKGROUND: The effect of single as compared with dual antiplatelet treatment on bleeding and thromboembolic events after transcatheter aortic-valve implantation (TAVI) in patients who do not have an indication for long-term anticoagulation has not been well studied. METHODS: In a randomized, controlled trial, we assigned a subgroup of patients who were undergoing TAVI and did not have an indication for long-term anticoagulation, in a 1:1 ratio, to receive aspirin alone or aspirin plus clopidogrel for 3 months. The two primary outcomes were all bleeding (including minor, major, and life-threatening or disabling bleeding) and non-procedure-related bleeding over a period of 12 months. Most bleeding at the TAVI puncture site was counted as non-procedure-related. The two secondary outcomes were a composite of death from cardiovascular causes, non-procedure-related bleeding, stroke, or myocardial infarction (secondary composite 1) and a composite of death from cardiovascular causes, ischemic stroke, or myocardial infarction (secondary composite 2) at 1 year, with both outcomes tested sequentially for noninferiority (noninferiority margin, 7.5 percentage points) and superiority. RESULTS: A total of 331 patients were assigned to receive aspirin alone and 334 were assigned to receive aspirin plus clopidogrel. A bleeding event occurred in 50 patients (15.1%) receiving aspirin alone and in 89 (26.6%) receiving aspirin plus clopidogrel (risk ratio, 0.57; 95% confidence interval [CI], 0.42 to 0.77; P = 0.001). Non-procedure-related bleeding occurred in 50 patients (15.1%) and 83 patients (24.9%), respectively (risk ratio, 0.61; 95% CI, 0.44 to 0.83; P = 0.005). A secondary composite 1 event occurred in 76 patients (23.0%) receiving aspirin alone and in 104 (31.1%) receiving aspirin plus clopidogrel (difference, -8.2 percentage points; 95% CI for noninferiority, -14.9 to -1.5; P<0.001; risk ratio, 0.74; 95% CI for superiority, 0.57 to 0.95; P = 0.04). A secondary composite 2 event occurred in 32 patients (9.7%) and 33 patients (9.9%), respectively (difference, -0.2 percentage points; 95% CI for noninferiority, -4.7 to 4.3; P = 0.004; risk ratio, 0.98; 95% CI for superiority, 0.62 to 1.55; P = 0.93). A total of 44 patients (13.3%) and 32 (9.6%), respectively, received oral anticoagulation during the trial. CONCLUSIONS: Among patients undergoing TAVI who did not have an indication for oral anticoagulation, the incidence of bleeding and the composite of bleeding or thromboembolic events at 1 year were significantly less frequent with aspirin than with aspirin plus clopidogrel administered for 3 months. (Funded by the Netherlands Organization for Health Research and Development; POPular TAVI EU Clinical Trials Register number, 2013-003125-28; ClinicalTrials.gov number, NCT02247128.).

Anticoagulation with or without Clopidogrel after Transcatheter Aortic-Valve Implantation.

BACKGROUND: The roles of anticoagulation alone or with an antiplatelet agent after transcatheter aortic-valve implantation (TAVI) have not been well studied. METHODS: We performed a randomized trial of clopidogrel in patients undergoing TAVI who were receiving oral anticoagulation for appropriate indications. Patients were assigned before TAVI in a 1:1 ratio not to receive clopidogrel or to receive clopidogrel for 3 months. The two primary outcomes were all bleeding and non-procedure-related bleeding over a period of 12 months. Procedure-related bleeding was defined as Bleeding Academic Research Consortium type 4 severe bleeding, and therefore most bleeding at the puncture site was counted as non-procedure-related. The two secondary outcomes were a composite of death from cardiovascular causes, non-procedure-related bleeding, stroke, or myocardial infarction at 12 months (secondary composite 1) and a composite of death from cardiovascular causes, ischemic stroke, or myocardial infarction (secondary composite 2), both tested for noninferiority (noninferiority margin, 7.5 percentage points) and superiority. RESULTS: Bleeding occurred in 34 of the 157 patients (21.7%) receiving oral anticoagulation alone and in 54 of the 156 (34.6%) receiving oral anticoagulation plus clopidogrel (risk ratio, 0.63; 95% confidence interval [CI], 0.43 to 0.90; P = 0.01); most bleeding events were at the TAVI access site. Non-procedure-related bleeding occurred in 34 patients (21.7%) and in 53 (34.0%), respectively (risk ratio, 0.64; 95% CI, 0.44 to 0.92; P = 0.02). Most bleeding occurred in the first month and was minor. A secondary composite 1 event occurred in 49 patients (31.2%) receiving oral anticoagulation alone and in 71 (45.5%) receiving oral anticoagulation plus clopidogrel (difference, -14.3 percentage points; 95% CI for noninferiority, -25.0 to -3.6; risk ratio, 0.69; 95% CI for superiority, 0.51 to 0.92). A secondary composite 2 event occurred in 21 patients (13.4%) and in 27 (17.3%), respectively (difference, -3.9 percentage points; 95% CI for noninferiority, -11.9 to 4.0; risk ratio, 0.77; 95% CI for superiority, 0.46 to 1.31). CONCLUSIONS: In patients undergoing TAVI who were receiving oral anticoagulation, the incidence of serious bleeding over a period of 1 month or 1 year was lower with oral anticoagulation alone than with oral anticoagulation plus clopidogrel. (Funded by the Netherlands Organization for Health Research and Development; POPular TAVI EU Clinical Trials Register number, 2013-003125-28; ClinicalTrials.gov number, NCT02247128.).

Prehospital paths and hospital arrival time of patients with acute coronary syndrome or stroke, a prospective observational study.

BACKGROUND: Patients with a presumed diagnosis of acute coronary syndrome (ACS) or stroke may have had contact with several healthcare providers prior to hospital arrival. The aim of this study was to describe the various prehospital paths and the effect on time delays of patients with ACS or stroke. METHODS: This prospective observational study included patients with presumed ACS or stroke who may choose to contact four different types of health care providers. Questionnaires were completed by patients, general practitioners (GP), GP cooperatives, ambulance services and emergency departments (ED). Additional data were retrieved from hospital registries. RESULTS: Two hundred two ACS patients arrived at the hospital by 15 different paths and 243 stroke patients by ten different paths. Often several healthcare providers were involved (60.8 % ACS, 95.1 % stroke). Almost half of all patients first contacted their GP (47.5 % ACS, 49.4 % stroke). Some prehospital paths were more frequently used, e.g. GP (cooperative) and ambulance in ACS, and GP or ambulance and ED in stroke. In 65 % of all events an ambulance was involved. Median time between start of symptoms and hospital arrival for ACS patients was over 6 h and for stroke patients 4 h. Of ACS patients 47.7 % waited more than 4 h before seeking medical advice compared to 31.6 % of stroke patients. Median time between seeking medical advice to arrival at hospital was shortest in paths involving the ambulance only (60 min ACS, 54 min stroke) or in combination with another healthcare provider (80 to 100 min ACS, 99 to 106 min stroke). CONCLUSIONS: Prehospital paths through which patients arrived in hospital are numerous and often complex, and various time delays occurred. Delays depend on the entry point of the health care system, and dialing the emergency number seems to be the best choice. Since reducing patient delay is difficult and noticeable differences exist between various prehospital paths, further research into reasons for these different entry choices may yield possibilities to optimize paths and reduce overall time delay.

Complex patients treated with zotarolimus-eluting resolute and everolimus-eluting Xience V stents in the randomized TWENTE trial: comparison of 2-year clinical outcome.

OBJECTIVE: To assess the differences in clinical outcome between complex patients treated with Resolute zotarolimus-eluting stents (ZES) versus Xience V everolimus-eluting stents (EES). BACKGROUND: Nowadays, many complex patients with coronary disease are treated with percutaneous coronary interventions, using drug-eluting stents (DES). METHODS: We analyzed 2-year outcome data of 1,033 complex patients of the TWENTE trial, treated with second-generation Resolute ZES or Xience V EES. Complex patients had at least one of the following characteristics: renal insufficiency (creatinine ≥ 140 µmol/l); ejection fraction < 30%; acute myocardial infarction (MI) within previous 72 hrs; >1 lesion/vessel; >2 vessels treated; lesion length > 27 mm; bifurcation; saphenous vein graft lesion; arterial bypass graft lesion; in-stent restenosis; unprotected left main lesion; lesion with thrombus; or lesion with total occlusion. Target vessel failure (TVF), the primary composite endpoint of the trial, was defined as cardiac death, target vessel-related MI, or target vessel revascularization. RESULTS: Among the 1,033 complex patients, 529 (51%) were treated with Resolute ZES and 504 (49%) with Xience V EES. Patient- and procedure-related characteristics were similar between DES groups. After 2-year follow-up, outcome was also similar between DES groups. TVF occurred in 12.1% of patients treated with Resolute ZES and 12.3% of patients treated with Xience V EES. In addition, DES groups did not differ significantly in cardiac death, MI, or target vessel revascularization-the individual components of TVF. CONCLUSION: Complex patients treated with Resolute ZES and Xience V EES showed similar safety and efficacy during 2-year follow-up. © 2014 Wiley Periodicals, Inc.

Clinical outcome following second-generation drug-eluting stent use for off-label versus on-label indications: insights from the two-year outcome of the TWENTE trial.

AIMS: Drug-eluting stents (DES) were first used on-label - in simple patients with low clinical risk and easily accessible lesions. Currently, DES are increasingly used off-label - in complex patients undergoing percutaneous coronary interventions (PCI) with historically higher event risk. Therefore, our aim was to investigate whether patients with off-label indications for DES use had similar outcomes compared to patients who were treated for on-label indications only. We analysed two-year follow-up data of 1,387 TWENTE trial patients, treated with second-generation everolimus-eluting XIENCE V or zotarolimus-eluting Resolute stents, and compared off-label vs. on-label DES use with regard to the following clinical endpoints: cardiac death, myocardial infarction (MI), periprocedural MI (≤48 hrs), and target vessel revascularisation (TVR). Patients with off-label DES use (n=1,033; 74.5%) had more diabetes (22.9% vs. 17.5%; p=0.032), previous MI (35.9% vs. 22.3%; p<0.001), type B2/C lesions (84.7% vs. 62.7%; p<0.001), and acute coronary syndromes (57.8% vs. 33.3%; p<0.001). Nevertheless, cardiac death and TVR rates were similar to those of patients with on-label DES use (p>0.8). Following off-label DES use, there was a higher incidence of PMI (5.0% vs. 1.4%; p=0.003), of which only 1.1% reached creatine kinase levels >5x the upper limit of normal (ULN). Despite differences in risk profile, patients with off-label DES use did not differ from patients with on-label DES use in clinical endpoints other than periprocedural MI. These largely positive findings underline the favourable safety profile of second-generation DES.

Third-generation zotarolimus-eluting and everolimus-eluting stents in all-comer patients requiring a percutaneous coronary intervention (DUTCH PEERS): a randomised, single-blind, multicentre, non-inferiority trial.

BACKGROUND: Third-generation, permanent-polymer-based drug-eluting stents with novel, flexible designs might be more easily delivered than previous generations of stents in complex coronary lesions, but might be less longitudinally stable. We aimed to assess the safety and efficacy in all-comer patients of two third-generation stents that are often used clinically, but that have not yet been compared, and one of which has not previously been assessed in a randomised trial. METHODS: In this investigator-initiated, single-blind, multicentre, randomised, two-arm, non-inferiority trial, patients aged 18 years and older who required a percutaneous coronary intervention with implantation of a drug-eluting stent were recruited from four study sites in the Netherlands. We randomly assigned patients by independently managed computer-generated allocation sequences in a 1:1 ratio to receive either cobalt-chromium-based zotarolimus-eluting stents (Resolute Integrity, Medtronic, Santa Rosa, CA, USA) or platinum-chromium-based everolimus-eluting stents (Promus Element, Boston Scientific, Natick, MA, USA). Patients and analysts were masked to the allocated stent, but treating clinicians were not. The primary endpoint of target-vessel failure was a composite of safety (cardiac death or target-vessel-related myocardial infarction) and efficacy (target-vessel revascularisation) at 12 months, analysed by intention to treat (with a non-inferiority margin of 3·6%). This trial is registered with ClinicalTrials.gov, number NCT01331707. FINDINGS: Between Nov 25, 2010, and May 24, 2012, 1811 eligible all-comer patients, with 2371 target lesions, were enrolled in the study. 370 (20%) patients presented with ST-elevation myocardial infarction and 447 (25%) with non-ST-elevation myocardial infarction. 906 patients were assigned to receive zotarolimus-eluting stents and 905 to receive everolimus-eluting stents. Ease of stent delivery was shown by very low numbers of patients requiring treatment other than their assigned study treatment (six [1%] in the zotarolimus-eluting stent group vs five [1%] in the everolimus-eluting stent group; p=0·22). 12-month follow-up results were available for 1810 patients (one patient in the zotarolimus-eluting stent group withdrew consent). The primary endpoint was met by 55 (6%) of 905 patients in the zotarolimus-eluting stent group and 47 (5%) of 905 in the everolimus-eluting stent group. The zotarolimus-eluting stent was non-inferior to the everolimus-eluting stent (absolute risk difference 0·88%, 95% CI -1·24% to 3·01%; upper limit of one-sided 95% CI 2·69%; non-inferiority p=0·006). We noted no significant between-group differences in individual components of the primary endpoint. Definite stent thrombosis occurred in three (0·3%) patients in the zotarolimus-eluting stent group and six (0·7%) patients in the everolimus-eluting stent group (p=0·34). Longitudinal stent deformation was seen only in the everolimus-eluting stent group (nine [1·0%] of 905 vs 0 of 906, p=0·002; nine of 1591 [0·6%] everolimus-eluting stents implanted became deformed), but was not associated with any adverse events. INTERPRETATION: Both stents were similarly efficacious and safe, and provided excellent clinical outcomes, especially in view of the large number of patients who presented with acute myocardial infarctions. FUNDING: Boston Scientific, Medtronic.

Comparison of eligible non-enrolled patients and the randomised TWENTE trial population treated with Resolute and Xience V drug-eluting stents.

AIMS: The TWENTE trial recently enrolled more than 80% of all eligible patients, who were randomised to zotarolimus-eluting Resolute or everolimus-eluting XIENCE V stents. In the present study, we investigated whether eligible, non-enrolled patients differed from the randomised TWENTE trial population in baseline characteristics and one-year outcome. METHODS AND RESULTS: Characteristics of 1,709 eligible patients were analysed. Independent external adjudication of clinical events was likewise performed for non-enrolled (n=318) and randomised patients (n=1,391). Non-enrolled and randomised patients did not differ in gender distribution, diabetes mellitus, and clinical presentation, but differed significantly in age and cardiovascular history. Nevertheless, clinical outcome after one year did not differ in the primary composite endpoint target-vessel failure (TVF; 9.8% vs. 8.1%; p=0.34), and its components cardiac death (1.6% vs. 1.2%; p=0.61), target vessel-related myocardial infarction (4.7% vs. 4.6%; p=0.92), and target-vessel revascularisation (3.8% vs. 3.0%; p=0.48). Previous bypass surgery predicted TVF in non-enrolled patients (p=0.001); removal of these patients resulted in identical TVF rates for non-enrolled and randomised patients (7.3% vs. 7.3%; p=0.99). CONCLUSIONS: Despite some differences in baseline characteristics, non-enrolled and randomised patients did not differ in one-year outcome, which was favourable for both populations and may be related to the drug-eluting stents used.

Impact of analyzing fewer image frames per segment during offline volumetric radiofrequency-based intravascular ultrasound measurements of target lesions prior to percutaneous coronary interventions.

In the present study, we evaluated the impact of a 50% reduction in number of image frames (every second frame) on the analysis time and variability of offline volumetric radiofrequency-based intravascular ultrasound (RF-IVUS) measurements in target lesions prior to percutaneous coronary interventions (PCI). Volumetric RF-IVUS data of vessel geometry and plaque composition are generally obtained by a semi-automated analysis process that includes time-consuming manual contour editing. A reduction in the number of frames used for volumetric analysis may speed up the analysis, but could increase measurement variability. We repeatedly performed offline volumetric analyses in RF-IVUS image sets of 20 mm-long coronary segments that contained 30 de novo lesions prior to PCI. A 50% reduction in frames decreased the analysis time significantly (from 57.5 ± 7.3 to 35.7 ± 3.7 min; P < 0.0001) while geometric and compositional RF-IVUS measurements did not differ significantly from measurements obtained from all frames. The variability between measurements on the reduced number of frames versus all frames was comparable to the intra-observer measurement variability. In target lesions prior to PCI, offline volumetric RF-IVUS analyses can be performed using a reduced number of image frames (every second frame). This reduces the time of analysis without substantially increasing measurement variability.

Impact of analyzing less image frames per segment for radiofrequency-based volumetric intravascular ultrasound measurements in mild-to-moderate coronary atherosclerosis.

Volumetric radiofrequency-based intravascular ultrasound (RF-IVUS) data of coronary segments are increasingly used as endpoints in serial trials of novel anti-atherosclerotic therapies. In a relatively time-consuming process, vessel and lumen contours are defined; these contours are first automatically detected, then visually checked, and finally (in most cases) manually edited to generate reliable volumetric data of vessel geometry and plaque composition. Reduction in number of cross-sectional images for volumetric analysis could save analysis time but may also increase measurement variability of volumetric data. To assess whether a 50% reduction in number of frames per segment (every second frame) alters the reproducibility of volumetric measurements, we performed repeated RF-IVUS analyses of 15 coronary segments with mild-to-moderate atherosclerosis (20.2 +/- 0.2 mm-long segments with 46 +/- 13% plaque burden). Volumes were calculated based on a total of 731 image frames. Reducing the number of cross-sectional image frames for volumetric measurements saved analysis time (38 +/- 9 vs. 68 +/- 17 min/segment; P < 0.0001) and resulted for only a few parameters in (borderline) significant but mild differences versus measurements based on all frames (fibrous volume, P < 0.05; necrotic-core volume, P = 0.07). Compared to the intra-observer variability, there was a mild increase in measurement variability for most geometrical and compositional volumetric RF-IVUS parameters. In RF-IVUS studies of mild-to-moderate coronary disease, analyzing less image frames saved analysis time, left most volumetric parameters greatly unaffected, and resulted in a no more than mild increase in measurement variability of volumetric data.

Coating irregularities of durable polymer-based drug-eluting stents as assessed by scanning electron microscopy.

AIMS: To classify and quantify post-expansion irregularities in durable polymer-based coatings of drug-eluting stents (DES). METHODS AND RESULTS: Taxus Liberté, Endeavor Sprint, Endeavor Resolute and Xience V DES (three samples of each) were explored by light microscopy and scanning electron microscopy (SEM) following expansion at 14 atm in water. Incidence and size of irregularities were measured during thorough quantitative examinations of a 360 SEM images. DES types examined showed a significant difference in the incidence of irregularities (p<0.0001; 6.6+/-4.2/image at 60-fold magnification) with typical patterns specific for each DES. All types showed areas with bare metal-aspects, but incidence, shape, and size differed largely: Sprint showed the largest areas. Cracks were only found in Sprint and Resolute, while wrinkles were seen exclusively in Taxus Liberté and Xience V (p<0.0001). The coating of each DES type showed some inhomogeneity of distribution, but the incidence differed (p<0.0001) and was least in Taxus Liberté, which, on the other hand, was the only DES that showed webbing with large bare-metal exposure. CONCLUSIONS: The incidence and size of various coating irregularities on different types of DES varied widely. These data may be considered in ongoing discussions on the differences between DES and may serve as reference to compare novel DES.

Reproducibility of volumetric intravascular ultrasound radiofrequency-based analysis of coronary plaque composition in vivo.

Intravascular ultrasound radiofrequency (RF-IVUS) data permit the analysis of coronary plaque composition in vivo and is used as an endpoint of ongoing pharmacological intervention trials. We assessed the reproducibility of volumetric RF-IVUS analyses in mild-to-moderately diseased atherosclerotic human coronary arteries in vivo. A total of 9,212 IVUS analyses on cross-sectional IVUS frames was performed to evaluate the reproducibility of volumetric RF-IVUS measurements in 33 coronary segments with a length of 27 +/- 7 mm. For vessel, lumen, and plaque + media volume the relative measurement differences (P = NS for all) were (A = intraobserver comparison, same pullback) -0.40 +/- 1.0%; -0.48 +/- 1.4%; -0.35 +/- 1.6%, (B = intraobserver comparison, repeated pullback) -0.42 +/- 1.2%; -0.52 +/- 1.8%; -0.43 +/- 4.5% (C = interobserver comparison, same pullback) 0.71 +/- 1.8%; 0.71 +/- 2.2%, and 0.89 +/- 5.0%, respectively. For fibrous, fibro-lipidic, calcium, and necrotic-core volumes the relative measurement differences (P = NS for all) were (A) 0.45 +/- 2.1%; -1.12 +/- 4.9%; -0.84 +/- 2.1%; -0.22 +/- 1.8%, (B) 1.40 +/- 4.1%; 1.26 +/- 6.7%; 2.66 +/- 7.4%; 0.85 +/- 4.4%, and (C) -1.60 +/- 4.9%; 3.85 +/- 8.2%; 1.66 +/- 7.5%, and -1.58 +/- 4.7%, respectively. Of note, necrotic-core volume showed on average the lowest measurement variability. Thus, in mild-to-moderate atherosclerotic coronary artery disease the reproducibility of volumetric compositional RF-IVUS measurements from the same pullback is relatively high, but lower than the reproducibility of geometrical IVUS measurements. Measurements from repeated pullbacks and by different observers show acceptable reproducibilities; the volumetric measurement of the necrotic-core shows on average the highest reproducibility of the compositional RF-IVUS measurements.

Relation between plaque progression and low-density lipoprotein cholesterol during aging as assessed with serial long-term (> or =12 months) follow-up intravascular ultrasound of the left main coronary artery.

Because of the clinical benefit of lipid lowering in older patients, we hypothesized that the relation between low-density lipoprotein (LDL) cholesterol serum levels and coronary plaque progression may persist throughout aging. We analyzed serial intravascular ultrasound (IVUS) data of 60 left main stems (18 +/- 9 months apart) and evaluated the relation between LDL cholesterol levels and coronary plaque progression at different ages. The population (n = 60) was divided into 3 groups according to age: tertile 1 (n = 20) was a mean age of 48 +/- 6 years (median 51, range 33 to 55), tertile 2 (n = 20) was a mean age of 58 +/- 2 years (median 59, range 55 to 61), and tertile 3 (n = 20) was a mean age of 66 +/- 6 years (median 65, range 61 to 83). Between groups, there was no significant difference in non-age-related demographics, clinical data, lipid profiles, or medications (e.g., statins). There was a positive linear relation between LDL cholesterol and annual changes in plaque plus media area in all age tertiles, which was statistically significant in tertiles 2 and 3 (r = 0.56, p <0.01; r = 0.50, p <0.02) and showed a strong trend in tertile 1 (r = 0.41, p = 0.07). The estimated LDL cholesterol thresholds, which, as determined by regression analysis, would correspond to no plaque progression, were 74, 60, and 78 mg/dl, respectively, in tertiles 1, 2, and 3. In conclusion, serial IVUS data in left main coronary arteries suggest that the relation between LDL cholesterol serum levels and plaque progression persists during aging.

Dedicated calibration formulas permit correction of differences between measurements by different IVUS devices as demonstrated in atherosclerotic human coronary arteries in vitro.

Serial intravascular ultrasound (IVUS) measurements of coronary vessel dimensions are major endpoints of studies focusing on pharmacological interventions, efficiency of drug eluting stents, and vascular remodeling. In serial studies measurement variability among different IVUS devices may cause substantial misinterpretation and error. We analyzed 33 human coronary plaques in vitro using two different IVUS systems (mechanical IVUS system with a 40 MHz Atlantis SR catheter; solid-state electronic IVUS system with a 20 MHz Invision catheter) and repeatedly measured the total vessel, lumen, and plaque + media cross-sectional area and plaque burden (plaque + media area divided by total vessel area). Between the "raw" measurements made by the two devices, there was a significant difference for both plaque + media area (2.35+/-1.86 mm(2), P < 0.01) and plaque burden (5.39+/-3.68%, P < 0.05). Measurements were then corrected by use of recently introduced calibration formulas; as a result the differences decreased significantly for all IVUS parameters measured ( P < 0.0001). After correction, the remaining differences between the corrected mechanical and solid-state IVUS measurements similar to differences between repeated measurements with the same IVUS device (i.e., the intraobserver variability). Thus, in serial studies the use of different IVUS devices at index and follow-up procedure may introduce a substantial error as a result of system-related differences. The application of dedicated calibration formulas allows for correction for these differences by decreasing such differences to the level of intraobserver variability.