Echocardiographic parameters of severe pulmonary regurgitation after surgical repair of tetralogy of Fallot.

AIMS: Reliable evaluation of the severity and consequences of pulmonary regurgitation (PR) in patients with repaired tetralogy of Fallot (TOF) is crucial to timely identify the need for pulmonary valve intervention. We aimed to identify the accuracy of echocardiographic parameters to differentiate between moderate and severe PR, using phase contrast cardiac magnetic resonance imaging (CMR) as gold standard. METHODS AND RESULTS: In this cross-sectional study, 45 TOF patients with both echocardiographic and CMR measurements of PR were enrolled. All quantitative and semiquantitative echocardiographic measurements such as pressure half time (PHT), Color flow jet width (CFJW), ratio CFJW/right ventricle outflow tract (RVOT) diameter, PR index and the presence of early termination of the PR jet, end-diastolic antegrade flow and diastolic backflow in main pulmonary artery (MPA), and PA branches correlated significantly with PR fraction on CMR. Qualitative assessment with color flow on echocardiography overestimated PR Multivariate linear regression analysis identified the ratio of CFJW/RVOT diameter and PHT as independent predictors of PR fraction. Accuracy of echo parameters was tested to differentiate between mild-to-moderate and severe PR Combining different echocardiographic parameters increased sensitivity and specificity. The addition of diastolic flow reversal in the PA branches to PHT below 167 milliseconds increased the NPV from 87% to 89% and PPV from 62% to 76%. CONCLUSIONS: Comparison with CMR confirms that echocardiographic parameters are reliable in predicting PR severity. Combined measurement of diastolic flow reversal in the pulmonary artery branches and PHT is reliable in the detection of severe PR in the follow-up of TOF patients.

Groupwise image registration based on a total correlation dissimilarity measure for quantitative MRI and dynamic imaging data.

The most widespread technique used to register sets of medical images consists of selecting one image as fixed reference, to which all remaining images are successively registered. This pairwise scheme requires one optimization procedure per pair of images to register. Pairwise mutual information is a common dissimilarity measure applied to a large variety of datasets. Alternative methods, called groupwise registrations, have been presented to register two or more images in a single optimization procedure, without the need of a reference image. Given the success of mutual information in pairwise registration, we adapt one of its multivariate versions, called total correlation, in a groupwise context. We justify the choice of total correlation among other multivariate versions of mutual information, and provide full implementation details. The resulting total correlation measure is remarkably close to measures previously proposed by Huizinga et al. based on principal component analysis. Our experiments, performed on five quantitative imaging datasets and on a dynamic CT imaging dataset, show that total correlation yields registration results that are comparable to Huizinga's methods. Total correlation has the advantage of being theoretically justified, while the measures of Huizinga et al. were designed empirically. Additionally, total correlation offers an alternative to pairwise mutual information on quantitative imaging datasets.

Multiple common comorbidities produce left ventricular diastolic dysfunction associated with coronary microvascular dysfunction, oxidative stress, and myocardial stiffening.

Aims: More than 50% of patients with heart failure have preserved ejection fraction characterized by diastolic dysfunction. The prevalance of diastolic dysfunction is higher in females and associates with multiple comorbidities such as hypertension (HT), obesity, hypercholesterolemia (HC), and diabetes mellitus (DM). Although its pathophysiology remains incompletely understood, it has been proposed that these comorbidities induce systemic inflammation, coronary microvascular dysfunction, and oxidative stress, leading to myocardial fibrosis, myocyte stiffening and, ultimately, diastolic dysfunction. Here, we tested this hypothesis in a swine model chronically exposed to three common comorbidities. Methods and results: DM (induced by streptozotocin), HC (produced by high fat diet), and HT (resulting from renal artery embolization), were produced in 10 female swine, which were followed for 6 months. Eight female healthy swine on normal pig-chow served as controls. The DM + HC + HT group showed hyperglycemia, HC, hypertriglyceridemia, renal dysfunction and HT, which were associated with systemic inflammation. Myocardial superoxide production was markedly increased, due to increased NOX activity and eNOS uncoupling, and associated with reduced NO production, and impaired coronary small artery endothelium-dependent vasodilation. These abnormalities were accompanied by increased myocardial collagen content, reduced capillary/fiber ratio, and elevated passive cardiomyocyte stiffness, resulting in an increased left ventricular end-diastolic stiffness (measured by pressure-volume catheter) and a trend towards a reduced E/A ratio (measured by cardiac MRI), while ejection fraction was maintained. Conclusions: The combination of three common comorbidities leads to systemic inflammation, myocardial oxidative stress, and coronary microvascular dysfunction, which associate with myocardial stiffening and LV diastolic dysfunction with preserved ejection fraction.

Serial quantitative magnetic resonance angiography follow-up of renal artery dimensions following treatment by four different renal denervation systems.

AIMS: Renal sympathetic denervation (RDN) is being studied as a therapeutic option for patients with therapy-resistant hypertension. It remains unclear if the procedure affects the renal arteries in such a way that luminal narrowing might occur at the mid to longer term. The aim of the present study was to assess renal artery integrity accurately at the medium to long term using recently validated quantitative magnetic resonance angiography software in patients treated with four different RDN devices. METHODS AND RESULTS: In a prospective cohort of 27 patients referred for RDN, quantitative magnetic resonance angiography (MRA) was used to assess 52 vessels at baseline, six, and 12 months post treatment with one of four different devices. No renal artery stenosis was seen at six or 12 months. The average mean lumen area was 26.6±7.3 mm2 at baseline versus 25.0±7.1 mm² and 25.0±6.1 mm² at six and 12 months, respectively, resulting in a late loss of 1.6 mm2 at six months and 1.9 mm2 at 12 months. No differences were observed in the arterial response to RDN with the four different systems used. There was no correlation between post-procedural dissections, oedema or thrombi as detected with invasive imaging, and luminal narrowing at follow-up. CONCLUSIONS: Quantitative MRA of patients treated with RDN revealed no significant change in renal artery dimensions up to 12-month follow-up. The lack of a change in renal artery luminal dimensions was irrespective of the arterial response to the individual devices used.

Cloud-processed 4D CMR flow imaging for pulmonary flow quantification.

OBJECTIVES: In this study, we evaluated a cloud-based platform for cardiac magnetic resonance (CMR) four-dimensional (4D) flow imaging, with fully integrated correction for eddy currents, Maxwell phase effects, and gradient field non-linearity, to quantify forward flow, regurgitation, and peak systolic velocity over the pulmonary artery. METHODS: We prospectively recruited 52 adult patients during one-year period from July 2014. The 4D flow and planar (2D) phase-contrast (PC) were acquired during same scanning session, but 4D flow was scanned after injection of a gadolinium-based contrast agent. Eddy-currents were semi-automatically corrected using the web-based software. Flow over pulmonary valve was measured and the 4D flow values were compared against the 2D PC ones. RESULTS: The mean forward flow was 92 (±30) ml/cycle measured with 4D flow and 86 (±29) ml/cycle measured with 2D PC, with a correlation of 0.82 and a mean difference of -6ml/cycle (-41-29). For the regurgitant fraction the correlation was 0.85 with a mean difference of -0.95% (-17-15). Mean peak systolic velocity measured with 4D flow was 92 (±49) cm/s and 108 (±56) cm/s with 2D PC, having a correlation of 0.93 and a mean difference of 16cm/s (-24-55). CONCLUSION: 4D flow imaging post-processed with an integrated cloud-based application accurately quantifies pulmonary flow. However, it may underestimate the peak systolic velocity.

Ischemic Postconditioning After Routine Thrombus Aspiration During Primary Percutaneous Coronary Intervention: Rationale and Design of the POstconditioning Rotterdam Trial.

BACKGROUND: Whether ischemic postconditioning (IPOC) immediately after routine thrombus aspiration (TA) reduces infarct size (IS) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) has not been established. STUDY DESIGN: The POstconditioning Rotterdam Trial (PORT) is a dual-center, prospective, open-label, randomized trial with blinded endpoint evaluation enrolling 72 subjects with first-time STEMI, and an occluded infarct-related artery (IRA) without collaterals undergoing PPCI. Subjects are randomized 1:1 to a strategy of IPOC immediately after TA followed by stenting of the IRA or to conventional percutaneous coronary intervention (PCI), including TA followed by stenting of the IRA (controls). Cardiac magnetic resonance imaging (MRI) is performed at 3-5 days after STEMI and at 3 months. The primary endpoint is IS at 3 months measured by delayed enhancement MRI. Other secondary endpoints include MRI-derived microvascular obstruction (MVO), left ventricular ejection fraction, myocardial salvage index, enzymatic IS, ST-segment resolution, myocardial blush grade, microcirculatory resistance, inflammation markers, and clinical events through 3-month follow-up. CONCLUSIONS: PORT is testing the hypothesis that adding IPOC (against lethal reperfusion injury) to TA (against distal embolization and MVO) is cardioprotective and reduces ultimate IS in STEMI patients undergoing PPCI (Dutch Trial Register identifier: NTR4040). © 2015 Wiley Periodicals, Inc.

Qualitative grading of aortic regurgitation: a pilot study comparing CMR 4D flow and echocardiography.

Over the past 10 years there has been intense research in the development of volumetric visualization of intracardiac flow by cardiac magnetic resonance (CMR).This volumetric time resolved technique called CMR 4D flow imaging has several advantages over standard CMR. It offers anatomical, functional and flow information in a single free-breathing, ten-minute acquisition. However, the data obtained is large and its processing requires dedicated software. We evaluated a cloud-based application package that combines volumetric data correction and visualization of CMR 4D flow data, and assessed its accuracy for the detection and grading of aortic valve regurgitation using transthoracic echocardiography as reference. Between June 2014 and January 2015, patients planned for clinical CMR were consecutively approached to undergo the supplementary CMR 4D flow acquisition. Fifty four patients(median age 39 years, 32 males) were included. Detection and grading of the aortic valve regurgitation using CMR4D flow imaging were evaluated against transthoracic echocardiography. The agreement between 4D flow CMR and transthoracic echocardiography for grading of aortic valve regurgitation was good (j = 0.73). To identify relevant,more than mild aortic valve regurgitation, CMR 4D flow imaging had a sensitivity of 100 % and specificity of 98 %. Aortic regurgitation can be well visualized, in a similar manner as transthoracic echocardiography, when using CMR 4D flow imaging.

Validation of renal artery dimensions measured by magnetic resonance angiography in patients referred for renal sympathetic denervation.

RATIONALE AND OBJECTIVES: Magnetic resonance angiography (MRA) is a well-established modality for the assessment of renal artery stenosis. Using dedicated quantitative analyses, MRA can become a useful tool for assessing renal artery dimensions in patients referred for renal sympathetic denervation (RDN) and for providing accurate measurements of vascular response after RDN. The purpose of this study was to test the reproducibility of a novel MRA quantitative imaging tool and to validate these measurements against intravascular ultrasound (IVUS). MATERIALS AND METHODS: In nine patients referred for renal denervation, renal artery dimensions were measured. Bland-Altman analysis was used to assess the intraobserver and interobserver reproducibility. RESULTS: Mean lumen diameter was 5.8 ± 0.7 mm, with a very good intraobserver and interobserver variability of 0.7% (reproducibility: bias, 0 mm; standard deviation [SD], 0.1 mm) and 1.2% (bias, 0 mm; SD, 0.1 mm), respectively. Mean total lumen volume was 1035.3 ± 403.6 mm(3) with good intraobserver and interobserver variability of 2.9% (bias, -9.7 mm(3); SD, 34.0 mm(3)) and 2.8% (bias, -11.4 mm(3); SD, 42.4 mm(3)). The correlation (Pearson R) between mean lumen diameter measured with MRA and IVUS was 0.750 (P = .002). CONCLUSIONS: Using a novel MRA quantitative imaging tool, renal artery dimensions can be measured with good reproducibility and accuracy. MRA-derived diameters and volumes correlated well with IVUS measurements.

VEGF165A microsphere therapy for myocardial infarction suppresses acute cytokine release and increases microvascular density but does not improve cardiac function.

Angiogenesis induced by growth factor-releasing microspheres can be an off-the-shelf and immediate alternative to stem cell therapy for acute myocardial infarction (AMI), independent of stem cell yield and comorbidity-induced dysfunction. Reliable and prolonged local delivery of intact proteins such as VEGF is, however, notoriously difficult. Our objective was to create a platform for local angiogenesis in human-sized hearts, using polyethylene-glycol/polybutylene-terephthalate (PEG-PBT) microsphere-based VEGF165A delivery. PEG-PBT microspheres were biocompatible, distribution was size dependent, and a regimen of 10 × 10(6) 15-µm microspheres at 0.5 × 10(6)/min did not induce cardiac necrosis. Efficacy, studied in a porcine model of AMI with reperfusion rather than chronic ischemia used for most reported VEGF studies, shows that microspheres were retained for at least 35 days. Acute VEGF165A release attenuated early cytokine release upon reperfusion and produced a dose-dependent increase in microvascular density at 5 wk following AMI. However, it did not improve major variables for global cardiac function, left ventricular dimensions, infarct size, or scar composition (collagen and myocyte content). Taken together, controlled VEGF165A delivery is safe, attenuates early cytokine release, and leads to a dose-dependent increase in microvascular density in the infarct zone but does not translate into changes in global or regional cardiac function and scar composition.

Prognostic value of microvascular obstruction and infarct size, as measured by CMR in STEMI patients.

The aim of this study was to evaluate the value of microvascular obstruction (MO) and infarct size as a percentage of left ventricular mass (IS%LV), as measured by contrast-enhanced cardiac magnetic resonance, in predicting major cardiovascular adverse events (MACE) at 2 years in patients with ST-segment elevation myocardial infarction reperfused by primary percutaneous coronary intervention. Individual data from 1,025 patients were entered into the pooled analysis. MO was associated with the occurrence of MACE, defined as a composite of cardiac death, congestive heart failure, and myocardial re-infarction (adjusted hazard ratio: 3.74; 95% confidence interval: 2.21 to 6.34). IS%LV ≥25% was not associated with MACE (adjusted hazard ratio: 0.90; 95% confidence interval: 0.59 to 1.37). The authors conclude that MO is an independent predictor of MACE and cardiac death, whereas IS%LV is not independently associated with MACE.

Atrial-based pacing has no benefit over ventricular pacing in preventing atrial arrhythmias in adults with congenital heart disease.

AIMS: To determine whether atrial-based pacing prevents atrial arrhythmias in adults with congenital heart disease (CHD) compared with ventricular pacing. METHODS AND RESULTS: All adult CHD patients from four participating centres with a permanent pacemaker were identified. Patients with permanent atrial arrhythmias at pacemaker implantation and patients who received a pacemaker for treatment of drug-refractory atrial arrhythmias were excluded. The final study population consisted of 211 patients (52% male, 36% complex CHD) who received a first pacemaker for sick sinus dysfunction (n = 82) or atrioventricular block (n = 129) at a median age of 24 years [interquartile range (IQR), 12-34]. A history of atrial arrhythmias at implantation was present in 49 patients (23%). Atrial-based pacing was the initial pacing mode in 139 patients (66%) while the others (34%) received ventricular pacing. During a median follow-up of 13 years (IQR, 7-21), 90 patients (43%) developed an atrial arrhythmia. Multivariate analysis demonstrated no significant effect of atrial-based pacing on subsequent atrial arrhythmias [hazard ratio (HR), 1.53; 95% confidence interval (CI), 0.91-2.56; P = 0.1]. Independent predictors of atrial arrhythmia were history of atrial arrhythmias (HR, 5.55; 95% CI, 3.47-8.89; P< 0.0001), older age (≥18 years) at pacemaker implantation (HR, 2.29; 95% CI, 1.29-4.04; P = 0.005), and complex CHD (HR, 1.57; 95% CI, 1.01-2.45; P = 0.04). CONCLUSION: In contrast to the general population, atrial-based pacing was not associated with a lower incidence of atrial arrhythmia in adults with CHD.

Complications of pacemaker therapy in adults with congenital heart disease: a multicenter study.

BACKGROUND: This study aims to investigate indications and complications of permanent cardiac pacing in adults with congenital heart disease (CHD). METHODS AND RESULTS: Two-hundred and seventy-four CHD patients were identified who underwent permanent pacemaker implantation between 1972 and 2009. The indication for pacing was acquired sinus node or AV node conduction disease (63%), sinus node or AV node conduction disease after cardiac surgery (28%), and drug/arrhythmia-related indications (9%). Patients with complex CHD received a pacemaker at younger age (23 versus 31 years, p<0.0001) and more often received an epicardial pacing system (51% versus 23%, p<0.0001) compared to those with simple or moderate CHD. Twenty-nine patients (10.6%) had a periprocedural complication during the primary pacemaker implantation (general population: 5.2%). The most common acute complications were lead dysfunction (4.0%), bleeding (2.6%), pocket infection (1.5%) and pneumothorax (1.5%). During a median follow-up of 12 years, pacemaker-related complications requiring intervention occurred in 95 patients (34.6%). The most common late pacemaker-related complications included lead failure (24.8%), pacemaker dysfunction/early battery depletion (5.1%), pacemaker migration (4.7%) and erosion (4.7%). Pacemaker implantation at younger age (<18 years) was an independent predictor of late pacemaker-related complication (adjusted hazard ratio 1.68, 95% confidence interval 1.07 to 2.63, p=0.023). CONCLUSIONS: The risk of periprocedural complications seems higher in the CHD population compared to the general population and more than one-third of CHD patients encountered a pacemaker-related complication during long-term follow-up. This risk increases for those who receive a pacemaker at younger age.