Biomedical subjects

Nico Bruining

Publications and source records attributed to Nico Bruining.

At least 19 recordsLinked to original sources

PubMed2006

Randomized double-blind comparison of sirolimus-eluting stent versus bare-metal stent implantation in diseased saphenous vein grafts: six-month angiographic, intravascular ultrasound, and clinical follow-up of the RRISC Trial.

OBJECTIVES: We sought to compare, in a randomized fashion, sirolimus-eluting stents (SES) versus bare-metal stents (BMS) in saphenous vein grafts (SVGs). BACKGROUND: Sirolimus-eluting stents reduce restenosis and repeated revascularization in native coronary arteries compared with BMS. However, randomized data in SVG are absent. METHODS: Patients with SVG lesions were randomized to SES or BMS. All were scheduled to undergo 6-month coronary angiography. The primary end point was 6-month angiographic in-stent late lumen loss. Secondary end points included binary angiographic restenosis, neointimal volume by intravascular ultrasound and major adverse clinical events (death, myocardial infarction, target lesion, and vessel revascularization). RESULTS: A total of 75 patients with 96 lesions localized in 80 diseased SVGs were included: 38 patients received 60 SES for 47 lesions, whereas 37 patients received 54 BMS for 49 lesions. In-stent late loss was significantly reduced in SES (0.38 +/- 0.51 mm vs. 0.79 +/- 0.66 mm in BMS, p = 0.001). Binary in-stent and in-segment restenosis were reduced, 11.3% versus 30.6% (relative risk [RR] 0.37; 95% confidence interval [CI] 0.15 to 0.97, p = 0.024) and 13.6% versus 32.6% (RR 0.42; 95% CI 0.18 to 0.97, p = 0.031), respectively. Median neointimal volume was 1 mm(3) (interquartile range 0 to 13) in SES versus 24 (interquartile range 8 to 34) in BMS (p < 0.001). Target lesion and vessel revascularization rates were significantly reduced, 5.3% versus 21.6% (RR 0.24; 95% CI 0.05 to 1.0, p = 0.047) and 5.3% versus 27% (RR 0.19; 95% CI 0.05 to 0.83, p = 0.012), respectively. Death and myocardial infarction rates were not different. CONCLUSIONS: Sirolimus-eluting stents significantly reduce late loss in SVG as opposed to BMS. This is associated with a reduction in restenosis rate and repeated target lesion and vessel revascularization procedures. (The RRISC Study; http://clinicaltrials.gov/ct/show; NCT00263263).

Aged↗

PubMed2006

Meta-analysis of the studies assessing temporal changes in coronary plaque volume using intravascular ultrasound.

To assess the temporal effect of statin therapy on coronary atherosclerotic plaque volume measured by intravascular ultrasound (IVUS), we searched PubMed for eligible studies published between 1990 and January 2006. Inclusion criteria for retrieved studies were (1) IVUS volume analysis at baseline and follow-up and (2) statin therapy in > or =1 group of patients. All data of interest were abstracted in prespecified structured collection forms. Statistical analysis was performed with Review Manager 4.2. Random-effect weighted mean difference (WMD) was used as summary statistics for comparison of continuous variables. Nine studies of 985 patients (with 11 statin treatment arms) were selected. After a mean follow-up of 9.8 +/- 4.9 months, we found a significant decrease in coronary plaque volume (WMD -5.77 mm(3), 95% confidence interval -10.36 to -1.17, p = 0.01), with no significant heterogeneity across studies (p = 0.47). Prespecified subgroup analyses showed similar trends. Studies in which the achieved low-density lipoprotein (LDL) cholesterol level was <100 mg/dl showed a trend for plaque regression (WMD -7.88 mm(3), 95% confidence interval -16.31 to 0.55, p = 0.07), whereas studies in which the achieved level of LDL cholesterol was > or =100 mg/dl, the trend was less evident (WMD -4.22 mm(3), 95% confidence interval -10.27 to 1.82, p = 0.17). Plaque volume remained essentially unchanged in patients not treated with statins (WMD 0.13 mm(3), 95% confidence interval -4.42 to 4.68, p = 0.96). In conclusion, statin therapy, particularly when achieving the target LDL level, appears to promote a significant regression of coronary plaque volume as measured by IVUS.

Cholesterol, LDL↗

PubMed2006

Multislice spiral computed tomography for the evaluation of stent patency after left main coronary artery stenting: a comparison with conventional coronary angiography and intravascular ultrasound.

BACKGROUND: Surveillance conventional coronary angiography (CCA) is recommended 2 to 6 months after stent-supported left main coronary artery (LMCA) percutaneous coronary intervention due to the unpredictable occurrence of in-stent restenosis (ISR), with its attendant risks. Multislice computed tomography (MSCT) is a promising technique for noninvasive coronary evaluation. We evaluated the diagnostic performance of high-resolution MSCT to detect ISR after stenting of the LMCA. METHODS AND RESULTS: Seventy-four patients were prospectively identified from a consecutive patient population scheduled for follow-up CCA after LMCA stenting and underwent MSCT before CCA. Until August 2004, a 16-slice scanner was used (n = 27), but we switched to the 64-slice scanner after that period (n = 43). Patients with initial heart rates > 65 bpm received beta-blockers, which resulted in a mean periscan heart rate of 57 +/- 7 bpm. Among patients with technically adequate scans (n = 70), MSCT correctly identified all patients with ISR (10 of 70) but misclassified 5 patients without ISR (false-positives). Overall, the accuracy of MSCT for detection of angiographic ISR was 93%. The sensitivity, specificity, and positive and negative predictive values were 100%, 91%, 67%, and 100%, respectively. When analysis was restricted to patients with stenting of the LMCA with or without extension into a single major side branch, accuracy was 98%. When both branches of the LMCA bifurcation were stented, accuracy was 83%. For the assessment of stent diameter and area, MSCT showed good correlation with intravascular ultrasound (r = 0.78 and 0.73, respectively). An intravascular ultrasound threshold value > or = 1 mm was identified to reliably detect in-stent neointima hyperplasia with MSCT. CONCLUSIONS: Current MSCT technology, in combination with optimal heart rate control, allows reliable noninvasive evaluation of selected patients after LMCA stenting. MSCT is safe to exclude left main ISR and may therefore be an acceptable first-line alternative to CCA.

Adrenergic beta-Antagonists↗

PubMed2006

Noninvasive detection of subclinical coronary atherosclerosis coupled with assessment of changes in plaque characteristics using novel invasive imaging modalities: the Integrated Biomarker and Imaging Study (IBIS).

OBJECTIVES: Our purpose was to assess noninvasive imaging in detection of subclinical atherosclerosis and to examine novel invasive modalities to describe prevalence and temporal changes in putative characteristics of "high-risk" plaques. BACKGROUND: Conventional coronary imaging cannot identify "high-risk" lesions. METHODS: Conventional (quantitative angiography and intravascular ultrasound [IVUS]) and novel imaging (IVUS-based palpography and gray scale echogenicity) were performed at baseline and 6 months later in 67 patients with diverse clinical presentations. Different imaging techniques were compared within a common segment defined by multislice computed tomography (MSCT). RESULTS: Compared with IVUS, the sensitivity, specificity, and positive and negative predictive value of MSCT for detecting significant plaque was 86%, 69%, 90%, and 61%, respectively. In coronary arteries with <50% stenosis, there were no temporal changes in luminal and plaque dimensions measured by quantitative coronary angiography or IVUS; however, a significant reduction in abnormal strain pattern was detected on palpography (density high strain spots/cm: 1.6 +/- 1.5 vs. 1.2 +/- 1.4, p = 0.0123. These changes were mainly related to significant changes in patients who presented with ST-segment elevation myocardial infarction. The assessment of plaque echogenicity showed no temporal changes. There were no correlations between circulating biomarkers and quantifiable imaging parameters. CONCLUSIONS: Mild angiographic disease is associated with large atherosclerotic plaques on MSCT. Conventional invasive coronary imaging reveals static luminal and plaque dimensions on standard medical therapy with plaque hypoechogenicity remaining unchanged over the 6-month period. By contrast, palpography measurements of strain correlate with clinical presentation and significantly decrease on standard medical therapy. Novel imaging modalities, such as palpography, might provide insights into plaque biology and might eventually serve as intermediate end points in interventional trials.

Coronary Angiography↗

PubMed2006

Revisiting late loss and neointimal volumetric measurements in a drug-eluting stent trial: analysis from the SPIRIT FIRST trial.

This study was conducted to reevaluate the significance of angiographic late loss and to assess the agreement between new proposed neointimal volumetric measurements derived from quantitative coronary angiography (QCA) and standard intravascular ultrasound (IVUS)-based parameters. Neointimal volumetric measurements may better estimate the magnitude of neointimal growth after stenting than late loss. In 56 in-stent segments (27, everolimus; 29, bare metal) in the SPIRIT FIRST study, we compared QCA measures with the corresponding IVUS parameters. Two IVUS-late loss models were derived from minimal luminal diameter (MLD) using either a circular model or a so-called projected MLD. QCA-neointimal volume was calculated as follows: stent volume (mean area of the stented segment x stent length) at post procedure - lumen volume (mean area of the stented segment x stent length) at follow-up (the stent length either from nominal stent length or the length measured by QCA). Videodensitometric neointimal volume was also evaluated. Each of the three neointimal volume and percentage volume obstruction by QCA showed significant correlation with the corresponding IVUS parameters (r = 0.557-0.594, P < 0.0001), albeit with a broad range of limits of agreement. Late loss and volumetric measurements by QCA had a broader range of standard deviation than those by IVUS. QCA-volumetric measurements successfully confirmed the efficacy of everolimus-eluting stents over bare metal stents (P < 0.05). Our proposed QCA volumetric measurements may be a practical surrogate for IVUS measurements and a discriminant methodological approach for assessment of treatment effects of drug-eluting stents.

Cardiovascular Agents↗

PubMed2005

In vivo variability in quantitative coronary ultrasound and tissue characterization measurements with mechanical and phased-array catheters.

BACKGROUND: Both mechanical and phased-array catheters are used in clinical trials to assess quantitative parameters. Only limited evaluation of the in vivo agreement of volumetrical measurements between such systems has been performed, despite the fact that such information is essential for the conduction of atherosclerosis regression trials. METHODS AND RESULTS: We prospectively evaluated the agreement in morphometric measurements and intravascular ultrasound (IVUS)-based plaque characterization between a 40 MHz rotating transducer (3.2 F Atlantis, Boston Scientific Corp.) and a 20 MHz phased-array catheter (2.9 F Eagle Eye, Volcano Therapeutics, Rancho Cordova, California) in 16 patients. Lumen (7.3+/-2.0 mm(2) vs. 6.7+/-1.8 mm(2), p=0.001) and vessel (11.8+/-3.3 mm(2) vs. 11.0+/-2.9 mm(2), p=0.02) cross-sectional areas (CSA) were significantly greater with the 20 MHz system. Plaque CSA measurements showed no significant difference between systems (4.4+/-2.3 mm(2) vs. 4.4+/-2.1). The relative differences were less than 10% for the three variables. On IVUS-based tissue characterization (13 patients), calculated percentage hypoechogenic volume was significantly higher for the 20 MHz system (96.7+/-2.38 vs. 88.4+/-5.53, p<0.0001). CONCLUSIONS: Quantitative IVUS analyses display significant catheter type-dependent variability. It is unclear whether the variability reflects overestimation of measurements with the phased-array or underestimation with the mechanical system. Although plaque burden measurements did not differ significantly between systems, it appears prudent to recommend the use of a single system for progression/regression studies.

Aged↗

PubMed2005

Evaluation of four-year coronary artery response after sirolimus-eluting stent implantation using serial quantitative intravascular ultrasound and computer-assisted grayscale value analysis for plaque composition in event-free patients.

OBJECTIVES: This study sought to evaluate the long-term arterial response after sirolimus-eluting stent implantation. BACKGROUND: Sirolimus-eluting stents are effective in inhibiting neointimal hyperplasia without affecting plaque volume behind the stent struts at six months. METHODS: Serial quantitative intravascular ultrasound and computer-assisted grayscale value analysis over four years were performed in 23 event-free patients treated with sirolimus-eluting stents. RESULTS: In the first two years, the mean plaque volume (155.5 +/- 42.8 mm3 post-procedure and 156.8 +/- 57.7 mm3 at two years, p = 0.86) and plaque compositional change expressed as mean percent hypoechogenic tissue of the plaque behind the stent struts (78.9 +/- 8.6% post-procedure and 78.2 +/- 8.9% at two years, p = 0.67) did not significantly change. However, significant plaque shrinking (change in plaque volume = -18.4 mm3, p = 0.02) with an increase in plaque echogenicity (change in percent hypoechogenic tissue = -7.8%, p < 0.0001) was observed between two and four years. The mean neointimal volume increased over four years from 0 to 8.4 +/- 5.8 mm3 (p < 0.0001). However, no further statistically significant change occurred between two and four years (7.0 +/- 6.7 mm3 vs. 8.4 +/- 5.8 mm3, p = 0.25). CONCLUSIONS: Between two and four years after sirolimus-eluting stent implantation, peri-stent tissue shrank with a concomitant increase in echogenicity. These intravascular ultrasound findings suggest that late chronic artery responses may evolve for up to four years after sirolimus-eluting stent implantation. In addition, the fact that the neointima does not significantly change from two to four years may suggest that the biological phenomenon of a delayed healing response has begun to subside.

Combined Modality Therapy↗

PubMed2005

Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography.

Assessment of attenuation (measured in Hounsfield units, HU) of human coronary plaques was performed using multislice computed tomography (MSCT) in an ex vivo model. In three ex vivo specimens of left coronary arteries in oil, MSCT was performed after intracoronary injection of four solutions of contrast material (400 mgI/ml iomeprol). The four solutions were diluted as follows: 1/infinity, 1/200, 1/80, and 1/20. All scans were performed with the following parameters: slices/collimation 16/0.75 mm, rotation time 375 ms. Each specimen was scored for the presence of atherosclerotic plaques. In each plaque the attenuation was measured in four regions of interest for lumen, plaque (non-calcified thickening of the vessel wall), calcium, and surrounding (oil surrounding the vessel). The results were compared with a one-way analysis of variance test and were correlated with Pearson's test. There were no significant differences in the attenuation of calcium and oil in the four solutions. The mean attenuation in the four solutions for lumen (35+/-10, 91+/-7, 246+/-18, 511+/-89 HU) and plaque (22+/-22, 50+/-26, 107+/-36, 152+/-67 HU) was significantly different between each decreasing dilution (p<0.001). The mean attenuation of lumen and plaque of coronary plaques showed high correlation, while the values were significantly different (r=0.73; p<0.001). Intracoronary attenuation modifies significantly the attenuation of plaques assessed with MSCT.

Cadaver↗

PubMed2005

Incomplete stent apposition after implantation of paclitaxel-eluting stents or bare metal stents: insights from the randomized TAXUS II trial.

BACKGROUND: The clinical impact of late incomplete stent apposition (ISA) for drug-eluting stents is unknown. We sought to prospectively investigate the incidence and extent of ISA after the procedure and at 6-month follow-up of paclitaxel-eluting stents in comparison with bare metal stents (BMS) and survey the clinical significance of ISA over a period of 12 months. METHODS AND RESULTS: TAXUS II was a randomized, double-blind study with 536 patients in 2 consecutive cohorts comparing slow-release (SR; 131 patients) and moderate-release (MR; 135 patients) paclitaxel-eluting stents with BMS (270 patients). This intravascular ultrasound (IVUS) substudy included patients who underwent serial IVUS examination after the procedure and at 6 months (BMS, 240 patients; SR, 113; MR, 116). The qualitative and quantitative analyses of ISA were performed by an independent, blinded core laboratory. More than half of the instances of ISA observed after the procedure resolved at 6 months in all groups. No difference in the incidence of late-acquired ISA was observed among the 3 groups (BMS, 5.4%; SR, 8.0%; MR, 9.5%; P=0.306), with a similar ISA volume (BMS, 11.4 mm3; SR, 21.7 mm3; MR, 8.5 mm3; P=0.18). Late-acquired ISA was the result of an increase of vessel area without change in plaque behind the stent. Predictive factors of late-acquired ISA were lesion length, unstable angina, and absence of diabetes. No stent thrombosis occurred in the patients diagnosed with ISA over a period of 12 months. CONCLUSIONS: The incidence and extent of late-acquired ISA are comparable in paclitaxel-eluting stents and BMS. ISA is a pure IVUS finding without clinical repercussions.

Aged↗

PubMed2005

Geometrical validation of intravascular ultrasound radiofrequency data analysis (Virtual Histology) acquired with a 30 MHz boston scientific corporation imaging catheter.

Recently, the plaque characterization field was explored with the use of the substrate (frequency domain analysis) rather than the envelope (amplitude or gray-scale imaging) of the intravascular ultrasound (IVUS) radiofrequency data. However, there is no data about the agreement of quantitative outcome between the two methods. The aim of this study was to assess the correlation and agreement between quantitative coronary ultrasound and the geometrical measurements provided by the spectral analysis of ultrasound radiofrequency data [IVUS-Virtual Histology (IVUS-VH), Volcano Therapeutics). Twenty-five patients were included in this study. The IVUS catheter used was a commercially available mechanical sector scanner (Ultracross 2.9 Fr 30 MHz catheter, Boston Scientific) covered with an outer sheath. IVUS-VH significantly underestimated lumen [relative difference (RD)=14.8+/-5.6; P<0.001], vessel (RD=14.1+/-4.8; P<0.001), and plaque (RD=11.5+/-10.8; P<0.001) cross-sectional areas (CSAs). Nevertheless, when adjusted for the ultrasound propagation delay caused by the sheath, relative differences of measurements were remarkably low (0.49%+/-6.3%, P=0.64 for lumen; 2.33%+/-4.6%, P=0.007 for vessel; and 4.2%+/-10.4%, P=0.005 for plaque CSA). These data suggest that the volumetric output of the IVUS-VH software underestimates measurements when acquired with a 30 MHz catheter. However, after applying a mathematical adjustment method for the ultrasound propagation delay caused by the outer sheath of the 30 MHz catheter, relative differences of direct measurements were negligible. These results suggest that ultrasound radiofrequency data analysis could provide, aside from precise compositional data, an accurate geometrical output.

Cardiac Catheterization↗

PubMed2005

Rationale and methods of the integrated biomarker and imaging study (IBIS): combining invasive and non-invasive imaging with biomarkers to detect subclinical atherosclerosis and assess coronary lesion biology.

Death or myocardial infarction, the most serious clinical consequences of atherosclerosis, often result from plaque rupture at non-flow limiting lesions. Current diagnostic imaging with coronary angiography only detects large plaques that already impinge on the lumen and cannot accurately identify those that have a propensity to cause unheralded events. Accurate evaluation of the composition or of the biomechanical characteristics of plaques with invasive or non-invasive methods, alone or in conjunction with assessment of circulating biomarkers, could help identify high-risk patients, thus providing the rationale for aggressive treatments in order to reduce future clinical events. The IBIS (Integrated Biomarker and Imaging Study) study is a prospective, single-center, non-randomized, observational study conducted in Rotterdam. The aim of the IBIS study is to evaluate both invasive (quantitative coronary angiography, intravascular ultrasound (IVUS) and palpography) and non-invasive (multislice spiral computed tomography) imaging techniques to characterize non-flow limiting coronary lesions. In addition, multiple classical and novel biomarkers will be measured and their levels correlated with the results of the different imaging techniques. A minimum of 85 patients up to a maximum of 120 patients will be included. This paper describes the study protocol and methodological solutions that have been devised for the purpose of comparisons among several imaging modalities. It outlines the analyses that will be performed to compare invasive and non-invasive imaging techniques in conjunction with multiple biomarkers to characterize non-flow limiting subclinical coronary lesions.

Adult↗

PubMed2005

Influence of increasing convolution kernel filtering on plaque imaging with multislice CT using an ex-vivo model of coronary angiography.

PURPOSE: To assess the variability in attenuation of coronary plaques with multislice CT-angiography (MSCT-CA) in an ex-vivo model with varying convolution kernels. MATERIALS AND METHODS: MSCT-CA (Sensation 16, Siemens) was performed in three ex-vivo left coronary arteries after instillation of contrast material solution (Iomeprol 400 mgI/ml, dilution: 1/80). The specimens were placed in oil to simulate epicardial fat. Scan parameters: slices 16/0.75 mm, rotation time 375 ms, feed/rotation 3.0 mm, mAs 500, slice thickness 1 mm, and FOV 50 mm. Datasets were reconstructed using 4 different kernels (B30f-smooth, B36f-medium smooth, B46f-medium, and B60f-sharp). Each scan was scored for the presence of plaques. Once a plaque was detected, the operator performed attenuation measurements (HU) in coronary lumen, oil, calcified and soft plaque tissue using the same settings in all datasets. The results were compared with T-test and correlated with Pearson's test. RESULTS: Overall, 464 measurements were performed. Significant differences (p<0.05) were found for the mean attenuation of lumen (B30f/B36f, B30f/B60f, B36f/B46f, B36f/B60f, and B46f/B60f), oil (B30f/B36f, B30f/B46f, B30f/B60f, B36f/B46f, and B46f/B60f), calcium (all kernels), and plaque (B30f/B36f, B30f/B46f, B30f/B60f, and B46f/B60f) using 4 different kernels. The attenuation values (mean+/-SD) within the lumen (246+/-6, 215+/-13, 248+/-5, and 270+/-7), oil (-123+/-3, -127+/-1, -121+/-6, and -127+/-4), calcified plaque tissue (703+/-334, 739+/-364, 817+/-381, and 1181+/-503), and soft plaque tissue (134+/-56, 111+/-49, 120+/-56, and 102+/-41) showed high correlation (p<0.001) when attenuation of all structures were compared in different kernels. CONCLUSIONS: Use of sharper convolution kernels significantly increases the attenuation of the calcium within coronary plaques and reduces the attenuation of soft plaque tissue.

Aged↗

PubMed2004

Retrospective image-based gating of intracoronary ultrasound images for improved quantitative analysis: the intelligate method.

Quantitative analysis of intracoronary ultrasound (ICUS) studies is performed on a series of tomographic cross-sectional ICUS images acquired during a motorized 0.5 mm/sec catheter pullback. Catheter displacement in the vascular lumen during the cardiac cycle causes an anatomically shuffled ICUS study, which results in a sawtooth-shaped appearance of the coronary segment in longitudinal reconstructed views in quantitative coronary ultrasound software packages. This hampers contour detection and leads to a laborious time-consuming semiquantitative analysis process that may produce inaccurate results. To solve these problems, in the past, online ECG-gated acquisition hardware has been applied. This article describes a novel image-based gating method called Intelligate, which features automatic retrospective selection of end-diastolic frames from videotaped or digitally stored ICUS studies. Our evaluation shows that there are no quantitative differences between analysis results of hardware ECG-gated and Intelligated ICUS studies.

Coronary Circulation↗

PubMed2004

Adjustment method for mechanical Boston scientific corporation 30 MHz intravascular ultrasound catheters connected to a Clearview console. Mechanical 30 MHz IVUS catheter adjustment.

Intracoronary ultrasound (ICUS) is often used in studies evaluating new interventional techniques. It is important that quantitative measurements performed with various ICUS imaging equipment and materials are comparable. During evaluation of quantitative coronary ultrasound (QCU) software, it appeared that Boston Scientific Corporation (BSC) 30 MHz catheters connected to a Clearview ultrasound console showed smaller dimensions of an in vitro phantom model than expected. In cooperation with the manufacturer the cause of this underestimation was determined, which is described in this paper, and the QCU software was extended with an adjustment. Evaluation was performed by performing in vitro measurements on a phantom model consisting of four highly accurate steel rings (perfect reflectors) with diameters of 2, 3, 4 and 5 mm. Relative differences (unadjusted) of the phantom were respectively: 15.92, 13.01, 10.10 and 12.23%. After applying the adjustment: -0.96, -1.84, -1.35 and -1.43%. In vivo measurements were performed on 24 randomly selected ICUS studies. These showed differences for not adjusted vs. adjusted measurements of lumen-, vessel- and plaque volumes of -10.1 +/- 1.5, -6.7 +/- 0.9 and -4.4 +/- 0.6%. An off-line adjustment formula was derived and applied on previous numerical QCU output data showing relative differences for lumen- and vessel volumes of 0.36 +/- 0.51 and 0.13 +/- 0.31%. 30 MHz BSC catheters connected to a Clearview ultrasound console underestimate vessel dimensions. This can retrospectively be adjusted within QCU software as well as retrospectively on numerical QCU data using a mathematical model.

Cardiac Catheterization↗

PubMed2003

Effects of septal pacing on P wave characteristics: the value of three-dimensional echocardiography.

Interatrial septum (IAS) pacing has been proposed for the prevention of paroxysmal atrial fibrillation. IAS pacing is usually guided by fluoroscopy and P wave analysis. The authors have developed a new approach for IAS pacing using intracardiac echocardiography (ICE), and examined its effects on P wave characteristics. Cross-sectional images are acquired during pullback of the ICE transducer from the superior vena cava into the inferior vena cava by an electrocardiogram- and respiration-gated technique. The right atrium and IAS are then three-dimensionally reconstructed, and the desired pacing site is selected. After lead placement and electrical testing, another three-dimensional reconstruction is performed to verify the final lead position. The study included 14 patients. IAS pacing was achieved at seven suprafossal (SF) and seven infrafossal (IF) lead locations, all confirmed by three-dimensional imaging. IAS pacing resulted in a significant reduction of P wave duration as compared to sinus rhythm (99.7 +/- 18.7 vs 140.4 +/- 8.8 ms; P < 0.01). SF pacing was associated with a greater reduction of P wave duration than IF pacing (56.1 +/- 9.9 vs 30.2 +/- 13.6 ms; P < 0.01). P wave dispersion remained unchanged during septal pacing as compared to sinus rhythm (21.4 +/- 16.1 vs 13.5 +/- 13.9 ms; NS). Three-dimensional intracardiac echocardiography can be used to guide IAS pacing. SF pacing was associated with a greater decrease in P wave duration, suggesting that it is a preferable location to decrease interatrial conduction delay.

Adult↗

PubMed2003

Sensitivity and specificity of QCA in detecting coronary arterial remodeling after intracoronary brachytherapy: a comparison to serial volumetric three-dimensional intravascular ultrasound analysis. Can we detect positive remodeling by luminography?

BACKGROUND: After treatment with intracoronary brachytherapy, enlargement of lumen (negative late loss) at follow-up has been demonstrated. The aim of the study is to analyze the sensitivity and specificity of quantitative coronary angiography (QCA) parameters to detect a positive vessel remodeling after intracoronary -radiation as compared to intravascular ultrasound (IVUS). METHODS: Twenty-seven patients (27 vessels) treated with balloon angioplasty followed by catheter-based intracoronary -radiation with a (90)Strontium/(90)Yttrium source were assessed by both QCA and three-dimensional IVUS with electrocardiogram-gated pullback. Irradiated segments were analyzed over the total treatment length and in subsegment lengths of 5 mm. RESULTS: Change in minimum luminal diameter (MLD) was not a predictor for the positive remodeling in either total irradiated segments or 5 mm subsegments, with a 54.3% ROC curve area [95% confidence interval (CI), 30-79%], sensitivity of 39% and specificity of 44% (p = not significant) in the total irradiated segments and a 55.9% ROC curve area (95% CI, 46-66%), sensitivity of 55% and specificity of 54% (p = not significant) in the 5 mm subsegments. Changes in mean and maximal lumen diameter were not significant parameters to detect positive vessel remodeling. When only central subsegments were analyzed, change in MLD was a significant predictor, with a 63.3% ROC curve area (95% CI, 52-75%), sensitivity of 55% and specificity of 64% (p = 0.029). CONCLUSION: Lumen enlargement detected by QCA does not reliably indicate a positive vessel remodeling after intracoronary radiation. IVUS analysis may be necessary to investigate the mechanism of restenosis after balloon angioplasty followed by catheter-based radiation.

Angioplasty, Balloon, Coronary↗

PubMed2002

Interatrial septum pacing guided by three-dimensional intracardiac echocardiography.

OBJECTIVES: Currently, the interatrial septum (IAS) pacing site is indirectly selected by fluoroscopy and P-wave analysis. The aim of the present study was to develop a novel approach for IAS pacing using intracardiac echocardiography (ICE). BACKGROUND: Interatrial septum pacing may be beneficial for the prevention of paroxysmal atrial fibrillation. METHODS: Cross-sectional images are acquired during a pull-back of the ICE transducer from the superior vena cava into the inferior vena cava by an electrocardiogram- and respiration-gated technique. Both atria are then reconstructed using three-dimensional (3D) imaging. Using an "en face" view of the IAS, the desired pacing site is selected. Following lead placement and electrical testing, another 3D reconstruction is performed to verify the final lead position. RESULTS: Twelve patients were included in this study. The IAS pacing was achieved in all patients including six suprafossal (SF) and six infrafossal (IF) lead locations all confirmed by 3D imaging. The mean duration times of atrial lead implantation and fluoroscopy were 70 +/- 48.9 min and 23.7 +/- 20.6 min, respectively. The IAS pacing resulted in a significant reduction of the P-wave duration as compared to sinus rhythm (98.9 +/- 19.3 ms vs. 141.3 +/- 8.6 ms; p < 0.002). The SF pacing showed a greater reduction of the P-wave duration than IF pacing (59.4 +/- 6.6 ms vs. 30.2 +/- 13.6 ms; p < 0.004). CONCLUSIONS: Three-dimensional ICE is a feasible tool for guiding IAS pacing.

Adult↗

PubMed2002

Local intracoronary administration of antisense oligonucleotide against c-myc for the prevention of in-stent restenosis: results of the randomized investigation by the Thoraxcenter of antisense DNA using local delivery and IVUS after coronary stenting (ITALICS) trial.

OBJECTIVE: This study was designed to determine whether antisense oligodeoxynucleotides (ODN) directed against the nuclear proto-oncogene c-myc could inhibit restenosis when given by local delivery immediately after coronary stent implantation. BACKGROUND: Failure of conventional pharmacologic therapies to reduce the incidence of coronary restenosis after percutaneous revascularization techniques has prompted interest in the use of agents that target intracellular central regulatory mechanisms. METHODS: Eighty-five patients were randomly assigned to receive either 10 mg of phosphorothioate-modified 15-mer antisense ODN or saline vehicle by intracoronary local delivery after coronary stent implantation. The primary end point was percent neointimal volume obstruction measured by computerized analysis of electrocardiogram-gated intravascular ultrasound (IVUS) at six-month follow-up. Secondary end points included clinical outcome and quantitative coronary angiography analysis. RESULTS: Analysis of follow-up IVUS data was performed on 77 patients. In-stent volume obstruction was similar between groups (44 +/- 16% and 46 +/- 14%, placebo vs. ODN; p = 0.57; 95% confidence interval: -1.13 to 0.85). Minimum luminal diameter increased from 0.84 +/- 0.36 and 0.90 +/- 0.45 (p = 0.55) to 2.70 +/- 0.37 and 2.80 +/- 0.37 (p = 0.28) after stent implantation, which decreased to 1.50 +/- 0.61 and 1.50 +/- 0.53 (p = 0.98) by six months, yielding similar loss indexes (placebo vs. ODN, respectively). There were no differences in angiographic restenosis rates (38.5 and 34.2%; p = 0.81; placebo vs. ODN) or clinical outcome. CONCLUSIONS: Treatment with 10 mg of phosphorothioate-modified ODN directed against c-myc does not reduce neointimal volume obstruction or the angiographic restenosis rate in this patient population.

Aged↗