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Boudewijn J Krenning

Publications and source records attributed to Boudewijn J Krenning.

At least 19 recordsLinked to original sources
PubMed2006

True mitral annulus diameter is underestimated by two-dimensional echocardiography as evidenced by real-time three-dimensional echocardiography and magnetic resonance imaging.

BACKGROUND: Mitral annulus assessment is of great importance for the diagnosis and treatment of mitral valve disease. The present study sought to assess the value of real-time three-dimensional echocardiography for the assessment of true mitral annulus diameter (MAD). METHODS: One hundred and fifty patients (mean age 38 +/- 18 years) with adequate two-dimensional (2D) echocardiographic image quality underwent assessment of MAD(2D) and MAD(3D) (with real-time three-dimensional echocardiography). In a subgroup of 30 patients true MAD was validated with magnetic resonance imaging (MRI). RESULTS: There was a good interobserver agreement for MAD(2D) (mean difference = -0.25 +/- 2.90 mm, agreement: -3.16, 2.66) and MAD(3D) (mean difference = 0.29 +/- 2.03, agreement = -1.74, 2.32). Measurements of MAD(2D) and MAD(3D) were well correlated (R = 0.81, P < 0.0001). However, MAD(3D) was significantly larger than MAD(2D) (3.7 +/- 0.9 vs. 3.3 +/- 0.8 cm, P < 0.0001). In the subgroup of 30 patients with MRI validation, MAD(3D) and MAD(MRI) were significantly larger than MAD(2D) (3.3 +/- 0.5 and 3.4 +/- 0.5 cm vs. 2.9 +/- 0.4 cm, both P < 0.001). There was no significant difference between MAD(MRI) and MAD(3D). CONCLUSION: MAD(3D) can be reliably measured and is superior to MAD(2D) in the assessment of true mitral annular size.

Adult↗
PubMed2006

Usefulness of ultrasound contrast agent to improve image quality during real-time three-dimensional stress echocardiography.

Dobutamine stress echocardiography is an accepted tool for the diagnosis of coronary artery disease. Some investigators have claimed that 3-dimensional imaging improves the diagnostic accuracy of dobutamine stress echocardiography. The purpose of the present investigation was to examine the role of contrast echocardiography in the improvement of segmental quality and interobserver agreement during stress real-time 3-dimensional echocardiography (RT3DE). The study comprised 36 consecutive patients with stable chest pain referred for routine stress testing. Three-dimensional images were acquired with an RT3DE system with an X4 matrix-array transducer. All available reconstructed 2-dimensional segments were graded as optimal, good, moderate, or poor. Wall motion was scored as normal, mild hypokinesia, severe hypokinesia, akinesia, or dyskinesia. At peak stress, 466 of the 612 segments (76%) could be analyzed during conventional RT3DE. With contrast-enhanced RT3DE, the number of available segments increased to 553 (90%). The image quality index during conventional RT3DE was 2.2, whereas with contrast-enhanced RT3DE, it was 3.1. With conventional RT3DE, 2 independent observers agreed on the diagnosis of myocardial ischemia in 85 of 108 coronary territories (79%, kappa = 0.26). With contrast-enhanced RT3DE, agreement increased to 95 of 108 coronary territories (88%, kappa = 0.59). Study agreement on myocardial ischemia was present in 26 of 36 studies (72%, kappa = 0.43) with conventional RT3DE and in 32 of 36 studies (89%, kappa = 0.77) with contrast-enhanced RT3DE. In conclusion, during stress RT3DE, contrast-enhanced imaging significantly decreases the number of poorly visualized myocardial segments and improves interobserver agreement for the diagnosis of myocardial ischemia.

Cardiotonic Agents↗
PubMed2006

213Bi-[DOTA0, Tyr3]octreotide peptide receptor radionuclide therapy of pancreatic tumors in a preclinical animal model.

PURPOSE: The somatostatin analogue [DOTA0, Tyr3]octreotide (DOTATOC) has previously been labeled with low linear energy transfer (LET) beta-emitters, such as 177Lu or 90Y, for tumor therapy. In this study, DOTATOC labeled with the high-LET alpha-emitter, 213Bi, was evaluated. EXPERIMENTAL DESIGN: The radiolabeling, stability, biodistribution, toxicity, safety, and therapeutic efficacy of 213Bi-DOTATOC (specific activity 7.4 MBq/microg) were investigated. Biodistribution studies to determine somatostatin receptor specificity were done in Lewis rats at 1 and 3 hours postinjection. Histopathology of various organs was used to evaluated toxicity and safety. Therapeutic efficacy of 4 to 22 MBq 213Bi-DOTATOC was determined in a rat pancreatic carcinoma model. RESULTS: Radiolabeling of the 213Bi-DOTATOC was achieved with radiochemical purity >95% and an incorporation yield > or = 99.9%. Biodistribution data showed specific binding to somatostatin receptor-expressing tissues. Administration of free 213Bi, compared with 213Bi-DOTATOC, resulted in higher radioactivity accumulation at 3 hours postinjection in the kidneys [34.47 +/- 1.40% injected dose/g (ID/g) tissue versus 11.15 +/- 0.46%, P < 0.0001] and bone marrow (0.31 +/- 0.01% ID/g versus 0.06 +/- 0.02%, P < 0.0324). A significant decrease in tumor growth rate was observed in rats treated with >11 MBq of 213Bi-DOTATOC 10 days postinjection compared with controls (P < 0.025). Treatment with >20 MBq of 213Bi-DOTATOC showed significantly greater tumor reduction when compared with animals receiving <11 MBq (P < 0.02). CONCLUSIONS: 213Bi-DOTATOC showed dose-related antitumor effects with minimal treatment-related organ toxicity. No acute or chronic hematologic toxicities were observed. Mild, acute nephrotoxicity was observed without evidence of chronic toxicity. 213Bi-DOTATOC is a promising therapeutic radiopharmaceutical for further evaluation.

Animals↗
PubMed2006

Real-time transthoracic three-dimensional echocardiographic assessment of left ventricular volume and ejection fraction in congenital heart disease.

OBJECTIVE: The purpose of this study was to assess the (1) feasibility of real-time three-dimensional echocardiography (RT-3DE) data acquisition and (2) volumes and function of the abnormal left ventricle (LV) in adult patients with congenital heart disease (CHD), compared with magnetic resonance imaging (MRI) data. METHODS: Thirty-two patients (59% were male) with CHD were evaluated on the same day by MRI and RT-3DE. Acquisition of RT-3DE data sets was feasible in 29 of the 32 patients (91%). The time of 3D data acquisition was 4 +/- 2 minutes, and LV analysis was 17 +/- 5 minutes per patient for manual border tracing. RESULTS: A good correlation was observed between RT-3DE with manual border detection and MRI for LV end-diastolic volume (r = 0.97), LV end-systolic volume (r = 0.98), and LV ejection fraction (r = 0.94). CONCLUSION: RT-3DE is feasible for volumetric analysis of the abnormal LV allowing accurate determination of LV volume and ejection fraction compared with MRI in adult patients with CHD.

Adult↗
PubMed2006

Harmonic 3-D echocardiography with a fast-rotating ultrasound transducer.

Although the advantages of three-dimensional (3-D) echocardiography have been acknowledged, its application for routine diagnosis is still very limited. This is mainly due to the relatively long acquisition time. Only recently has this problem been addressed with the introduction of new real-time 3-D echo systems. This paper describes the design, characteristics, and capabilities of an alternative concept for rapid 3-D echocardiographic recordings. The presented fast-rotating ultrasound (FRU)-transducer is based on a 64-element phased array that rotates with a maximum speed of 8 Hz (480 rpm). The large bandwidth of the FRU-transducer makes it highly suitable for tissue and contrast harmonic imaging. The transducer presents itself as a conventional phased-array transducer; therefore, it is easily implemented on existing 2-D echo systems, without additional interfacing. The capabilities of the FRU-transducer are illustrated with in-vitro volume measurements, harmonic imaging in combination with a contrast agent, and a preliminary clinical study.

Echocardiography, Three-Dimensional↗
PubMed2006

Rapid and accurate measurement of left ventricular function with a new second-harmonic fast-rotating transducer and semi-automated border detection.

Measurement of left ventricular (LV) volume and function are the most common clinical referral questions to the echocardiography laboratory. A fast, practical, and accurate method would offer important advantages to obtain this important information. To validate a new practical method for rapid measurement of LV volume and function. We developed a continuous fast-rotating transducer, with second-harmonic capabilities, for three-dimensional echocardiography (3DE). Fifteen cardiac patients underwent both 3DE and magnetic resonance imaging (reference method) on the same day. 3DE image acquisition was performed during a 10-second breath-hold with a frame rate of 100 frames/sec and a rotational speed of 6 rotations/sec. The individual images were postprocessed with Matlab software using multibeat data fusion. Subsequently, with these images, 12 datasets per cardiac cycle were reconstructed, each comprising seven equidistant cross-sectional images for analysis in the new TomTec 4DLV analysis software, which uses a semi-automated border detection (ABD) algorithm. The ABD requires an average analysis time of 15 minutes per patient. A strong correlation was found between LV end-diastolic volume (r = 0.99; y = 0.95x - 1.14 ml; SEE = 6.5 ml), LV end-systolic volume (r = 0.96; y = 0.89x + 7.91 ml; SEE = 7.0 ml), and LV ejection fraction (r = 0.93; y = 0.69x + 13.36; SEE = 2.4%). Inter- and intraobserver agreement for all measurements was good. The fast-rotating transducer with new ABD software is a dedicated tool for rapid and accurate analysis of LV volume and function.

Adult↗
PubMed2005

Comparison of real-time three-dimensional echocardiography to magnetic resonance imaging for assessment of left ventricular mass.

This is the first study to assess the feasibility and accuracy of real-time 3-dimensional echocardiography (RT-3DE) for the measurements of left ventricular (LV) mass in patients with congenital heart disease (CHD) compared with magnetic resonance imaging (MRI). Twenty patients (60% men) with CHD were evaluated by MRI and RT-3DE on the same day. Their mean age was 29 +/- 8 years (range 19 to 49). RT-3DE was performed with a Philips Sonos 7500 echocardiographic system and LV mass analyses with the assistance of TomTec software. The results for LV mass obtained by manual tracing were compared with Signa 1.5-T MRI data. The acquisition of RT-3DE data sets was feasible in all 20 patients. Nine patients (45%) had good, 5 patients (25%) moderate, and 6 patients (30%) poor image quality of the 3-dimensional data set. The time of 3-dimensional data acquisition was 4 +/- 2 minutes. Off-line image processing and tracing required approximately 11 +/- 3 minutes. A very good correlation was observed between RT-3DE data with sufficient image quality and MRI (r = 0.98, y = 0.96x + 4.1, SEE 9.8 g), with a mean difference of 2.0 +/- 20 g. Interobserver agreement was excellent (r = 0.99, y = 0.97x + 3.81), with a mean difference of -1 +/- 11 g. In conclusion, the assessment of LV mass from RT-3DE data is feasible in patients with CHD. The mass of an abnormally shaped left ventricle can be determined with high accuracy and low interobserver variability in patients with good or moderate echocardiographic image quality.

Adult↗
PubMed2005

Comparison of all-cause mortality in women with known or suspected coronary artery disease referred for dobutamine stress echocardiography with normal versus abnormal test results.

The presence of myocardial ischemia during dobutamine stress echocardiography is independently associated with an increased risk of all-cause mortality in women after adjustment for clinical data. This association is observed in patients who have proved coronary artery disease and in patients who have no history of coronary artery disease.

Cause of Death↗
PubMed2005

Seven-year follow-up after dobutamine stress echocardiography: impact of gender on prognosis.

OBJECTIVES: The aim of this study was to investigate the effects of gender on long-term prognosis of patients undergoing dobutamine stress echocardiography (DSE). BACKGROUND: Gender differences in the predictors of outcome among patients with known or suspected coronary artery disease undergoing DSE have not been adequately studied. METHODS: We studied 2,276 men and 1,105 women with known or suspected coronary artery disease who underwent DSE. Follow-up events were cardiac death and nonfatal myocardial infarction (MI). RESULTS: Dobutamine stress echocardiography was normal in 687 men (30%) and 483 women (44%) (p <0.0001). Ischemia on DSE was present in 1,194 men (52%) and 416 women (38%) (p <0.001). During a mean follow-up of 7 +/- 3.4 years, there were 894 (26%) deaths (442 attributed to cardiac causes) and 145 (4%) nonfatal MIs. The annual cardiac event rate was 2.5% in men and 1.2% in women with normal DSE. Independent predictors of cardiac events in patients with normal DSE using a Cox proportional hazards regression analysis were male gender (hazard ratio [HR]: 1.7 [range 1.1 to 2.8]), age (HR: 1.02 [range 1.01 to 1.04]), history of heart failure (HR: 3.4 [range 1.5 to 7.9]), previous MI (HR: 1.7 [range 1.1 to 2.8]), and diabetes (HR: 2.4 [range 1.3 to 4.5]). Independent predictors of cardiac events in patients with an abnormal DSE were age (HR: 1.03 [range 1.02 to 1.04]), history of heart failure (HR: 1.7 [range 1.3 to 2.1]), diabetes (HR: 1.4 [range 1.1 to 1.8]), heart rate at rest (HR: 2.8 [range 1.4 to 5.8]), wall motion abnormalities at rest (HR: 1.06 [range 1.04 to 1.09]), and ischemia on DSE (HR: 1.04 [range 1.02 to 1.07]). Myocardial ischemia was an independent predictor of cardiac events in both men and women. CONCLUSIONS: Dobutamine stress echocardiography provides independent prognostic information in both men and women. In patients with normal DSE, gender is independently associated with cardiac events. The outcome of patients with abnormal DSE is not related to gender, after adjusting for stress echocardiographic abnormalities.

Coronary Disease↗
PubMed2005

Left ventricular volume estimation in cardiac three-dimensional ultrasound: a semiautomatic border detection approach.

RATIONALE AND OBJECTIVES: We propose a semiautomatic endocardial border detection method for three-dimensional (3D) time series of cardiac ultrasound (US) data based on pattern matching and dynamic programming, operating on two-dimensional (2D) slices of the 3D plus time data, for the estimation of full cycle left ventricular volume, with minimal user interaction. MATERIALS AND METHODS: The presented method is generally applicable to 3D US data and evaluated on data acquired with the Fast Rotating Ultrasound (FRU-) Transducer, developed by Erasmus Medical Center (Rotterdam, the Netherlands), a conventional phased-array transducer, rotating at very high speed around its image axis. The detection is based on endocardial edge pattern matching using dynamic programming, which is constrained by a 3D plus time shape model. It is applied to an automatically selected subset of 2D images of the original data set, for typically 10 equidistant rotation angles and 16 cardiac phases (160 images). Initialization requires the drawing of four contours per patient manually. We evaluated this method on 14 patients against MRI end-diastole and end-systole volumes. Initialization requires the drawing of four contours per patient manually. We evaluated this method on 14 patients against MRI end-diastolic (ED) and end-systolic (ES) volumes. RESULTS: The semiautomatic border detection approach shows good correlations with MRI ED/ES volumes (r = 0.938) and low interobserver variability (y = 1.005x - 16.7, r = 0.943) over full-cycle volume estimations. It shows a high consistency in tracking the user-defined initial borders over space and time. CONCLUSIONS: We show that the ease of the acquisition using the FRU-transducer and the semiautomatic endocardial border detection method together can provide a way to quickly estimate the left ventricular volume over the full cardiac cycle using little user interaction.

Algorithms↗
PubMed2005

Pacemaker stress echocardiography predicts cardiac events in patients with permanent pacemaker.

PURPOSE: Noninvasive pacemaker stress echocardiography is a newly introduced method for the diagnosis of coronary artery disease in patients with a permanent pacemaker. The prognostic value of pacemaker stress echocardiography has not been studied. SUBJECTS AND METHODS: We studied 136 patients (mean age 64+/-12 years) with a permanent pacemaker who underwent pacemaker stress echocardiography for evaluation of coronary artery disease. All patients underwent pacemaker stress echocardiography by external programming (pacing heart rate up to ischemia or target heart rate). RESULTS: Thirty-one patients (23%) had normal study results. Ischemia was detected in 75 patients (55%). During a mean follow-up of 3.5+/-2.4 years, 35 deaths (26%) (20 the result of cardiac causes) and 2 nonfatal myocardial infarctions (1%) occurred. The annual cardiac death rate was 1.3% in patients without ischemia and 4.6% in patients with ischemia (P=.01). The annual all-cause mortality rate was 3.1% in patients without ischemia and 7% in patients with ischemia (P=.004). The presence of ischemia during pacemaker stress echocardiography was the strongest independent predictor of cardiac death (hazard ratio 4.1, confidence interval 1.2-14.5) and all-cause mortality (hazard ratio 2.7, confidence interval 1.2-6.0) in a multivariable model. CONCLUSION: Myocardial ischemia during pacemaker stress echocardiography is an independent predictor of cardiac death and all-cause mortality in patients with a permanent pacemaker.

Aged↗
PubMed2005

Long-term prediction of mortality in elderly persons by dobutamine stress echocardiography.

BACKGROUND: Dobutamine stress echocardiography (DSE) was shown to provide incremental prognostic information. However, its role in the prediction of mortality in elderly persons is not well defined. We assessed the value of DSE in the prediction of mortality and hard cardiac events during long-term follow-up in patients older than 65 years. METHODS: We studied 1434 patients >65 years old (mean age 72 +/- 3 years) who underwent DSE for evaluation of coronary artery disease. Ischemia was defined as new or worsening wall motion abnormalities. Follow-up events were total mortality and hard cardiac events (cardiac mortality and nonfatal myocardial infarction). Multivariable Cox regression analysis was used to identify the independent predictors of follow-up events. RESULTS: Ischemia was detected in 675 patients (47%). Five hundred six patients (35%) had a normal study, and 253 (18%) had fixed wall motion abnormalities. During a mean follow-up of 6.5 years, 532 (37%) deaths occurred, of which 249 (17%) were due to cardiac causes. A nonfatal myocardial infarction occurred in 45 patients (3%). Independent predictors of all-cause mortality in a multivariate analysis model were age (hazard ratio [HR] 1.06; 95% confidence interval [CI], 1.05-1.08), male sex (HR 1.5; 95% CI, 1.2-1.8), hypertension (HR 1.2; 95% CI, 1.1-1.4), smoking (HR 1.3; 95% CI, 1.1-1.6), diabetes (HR 1.4; 95% CI, 1.1-1.8), rest wall motion abnormalities (HR 1.07; 95% CI, 1.06-1.09), and ischemia (HR 1.3; 95% CI, 1.1-1.6). Independent predictors of hard cardiac events were age (HR 1.07; 95% CI, 1.05-1.09), male sex (HR 1.3; 95% CI, 1.1-1.7), smoking (HR 1.3; 95% CI, 1.1-1.6), diabetes (HR 1.6; 95% CI, 1.2-2.2), rest wall motion abnormalities (HR 1.13; 95% CI, 1.12-1.16), and ischemia (HR 2.1; 95% CI, 1.5-2.8). CONCLUSION: DSE provides independent prognostic information to predict all-cause mortality and hard cardiac events in elderly patients.

Aged↗
PubMed2004

Prognostic stratification of patients with right bundle branch block using dobutamine stress echocardiography.

The presence of a right bundle branch block (RBBB) is associated with increased mortality. We studied the role of dobutamine stress echocardiography for the prognostic stratification of patients with RBBB. The presence of an abnormal dobutamine stress echocardiography was the strongest predictor of cardiac events and provided incremental prognostic information to clinical and stress test data.

Aged↗
PubMed2004

QT dispersion correlates to myocardial viability assessed by dobutamine stress echocardiography in patients with severely depressed left ventricular function due to coronary artery disease.

BACKGROUND: QT dispersion is prolonged in numerous cardiac diseases, representing a general repolarization abnormality. AIM: To evaluate the influence of viable myocardium on QT dispersion in patients with severely depressed left ventricular (LV) function due to coronary artery disease. METHODS AND RESULTS: 103 patients with ischemic cardiomyopathy (LV ejection fraction [EF]: 25+/-6%) were studied. Patients underwent 12-lead electrocardiography to assess QT dispersion, and two-dimensional echocardiography to identify segmental dysfunction. Dobutamine stress echocardiography (DSE) was then performed to detect residual viability. Resting echo demonstrated 1260 dysfunctional segments; of these, 476 (38%) were viable. Substantial viability (> or =4 viable segments on DSE) was found in 62 (60%) patients. QT dispersion was lower in these patients, than in patients without viability (55+/-17 ms vs. 65+/-22 ms, P=0.012). Viable segments negatively correlated to QT dispersion (r=-0.333, P=0.001). In contrast, there was no correlation between LVEF and QT dispersion (r=-0.001, P=NS). CONCLUSIONS: There is a negative correlation between QT dispersion and the number of viable segments assessed by DSE. Patients with severely depressed LV function and a low QT dispersion probably have a substantial amount of viable tissue. Conversely, when QT dispersion is high, the likelihood of substantial viability is reduced.

Cardiomyopathies↗
PubMed2004

Pulsed-wave tissue Doppler quantification of systolic and diastolic function of viable and nonviable myocardium in patients with ischemic cardiomyopathy.

BACKGROUND: Detection of myocardial viability is crucial for clinical treatment of patients with ischemic cardiomyopathy. Currently, quantitative information for the evaluation of systolic and diastolic function of viable tissue is limited. Our aim was to compare quantitatively systolic and diastolic function in viable and nonviable dysfunctional myocardium in patients with ischemic cardiomyopathy. METHODS: A total of 93 patients (mean age, 62 +/- 10 years) underwent dobutamine stress echocardiography to assess myocardial viability. Pulsed-wave tissue Doppler imaging (TDI) was used to assess systolic ejection velocity (V(S)) and early (V(E)) and late (V(A)) diastolic velocities at rest and at low-dose dobutamine infusion (10 microg/kg per minute) in viable and nonviable dysfunctional regions. Analysis was repeated after dividing study population in patients >or=65 years old (n = 40) and <65 years old (n = 53). RESULTS: Pulsed-wave TDI demonstrated that V(S) was comparable in dysfunctional viable and nonviable regions at rest (V(S), 6.3 +/- 1.9 cm/s vs 6.3 +/- 2.0 cm/s, respectively, P = .93). However, at low-dose dobutamine challenge, V(S) was significantly higher in viable regions (8.5 +/- 2.7 cm/s vs 7.8 +/- 2.4 cm/s, P = .002). Viable regions had higher V(E) at rest compared with nonviable regions (8.4 +/- 2.5 cm/s vs 7.5 +/- 2.8 cm/s, P = .003). Myocardial velocities were significantly higher in patients >or=65 years old, both in viable and nonviable regions. CONCLUSIONS: Quantification of myocardial motion by pulsed-wave TDI demonstrates that at low-dose dobutamine stress, systolic velocity is markedly improved in viable myocardium, indicating the presence of contractile reserve in viable regions. A superior early diastolic filling at rest can also differentiate viable from nonviable myocardium.

Adult↗
PubMed2004

Guiding and optimization of resynchronization therapy with dynamic three-dimensional echocardiography and segmental volume--time curves: a feasibility study.

OBJECTIVE: To assess a new approach for guiding and hemodynamic optimization of resynchronization therapy, using three-dimensional (3D) transthoracic echocardiography. BACKGROUND: Resynchronization therapy for heart failure provides the greatest hemodynamic benefit when applied to the most delayed left ventricular (LV) site. Currently, the ideal LV pacing site is selected according to acute invasive hemodynamic assessment and/or tissue Doppler imaging. METHODS: A total of 16 patients with advanced heart failure and an implanted biventricular pacemaker were included in this study. Transthoracic apical LV images at equidistant intervals were obtained using a prototype, fast-rotating second harmonic transducer to reconstruct 3D LV datasets during sinus rhythm (SR), right ventricular (RV) apical and biventricular pacing mode. A semi-automated contour analysis system (4D LV analysis, TomTec, Germany) was used for segmental wall motion analysis and identification of the most delayed contracting segment and calculation of global LV function. RESULTS: Data acquisition duration was 10 s and analyzable 3D images were obtained in 12 patients. Of these patients, data during SR were available in 9 and during biventricular pacing in 11. The greatest contraction delay during SR was found in the anterior and antero-septal segments in five of nine patients. Biventricular pacing resulted in reduction of the contraction delay in seven of eight patients. The global LV function did not change significantly. CONCLUSION: 3D echocardiography with appropriate analytic software allows detection of the most delayed LV contracting segment and can be used to select the optimal pacing site during resynchronization therapy.

Aged↗