Niek H. J. Prakken

Echocardiographic tissue deformation imaging of right ventricular systolic function in endurance athletes

AIMS To investigate the physiological adaptation of the right ventricle (RV) in response to endurance training and to define reference values for regional deformation in the RV in endurance athletes. METHODS AND RESULTS Healthy controls (n = 61), athletes (n = 58), and elite athletes (n = 63) were prospectively enrolled with a training intensity of 2.2 +/- 1.6, 12.5 +/- 2.3 and 24.2 +/- 5.7 h/week, respectively (P < 0.001). Conventional echocardiographic parameters, tissue Doppler imaging (TDI), and 2D strain echo (2DSE)-derived velocity, strain, and strain rate (SR) were calculated in three RV segments. Left ventricular and RV dimensions were significantly increased (P < 0.001) in both groups of athletes compared with controls. Right ventricular systolic velocities and displacement were not different between the groups. Right ventricular strain and SR values were reduced in the RV basal and mid-segment in athletes. Athletes with marked RV dilatation showed lower strain and SR values in the basal (-20.9 +/- 4.7 vs. -24.5 +/- 4.9%, P < 0.001 and -1.23 +/- 0.31 vs. -1.50 +/- 0.33 s(-1), P < 0.001) and mid (-29.3 +/- 5.4 vs. -32.1 +/- 5.3%, P = 0.017 and -1.58 +/- 0.41 vs. -1.82 +/- 0.42 s(-1), P = 0.009) segment, whereas athletes without RV dilatation showed no significant difference compared with the controls. CONCLUSION Regional deformation and deformation rates (TDI and 2DSE) are reduced in the basal RV segment in athletes. This phenomenon is most pronounced in athletes with RV dilatation and should be interpreted as normal when evaluating athletes suspected for RV pathology.

Sympathetic activity in chronic kidney disease patients is related to left ventricular mass despite antihypertensive treatment

BACKGROUND Chronic kidney disease (CKD) patients often have sympathetic hyperactivity, which contributes to the pathogenesis of hypertension and cardiovascular organ damage. Angiotensin-converting enzyme (ACE) inhibitors (ACEi) and angiotensin II receptor blockers (ARB) reduce sympathetic hyperactivity. Ideally, treatment should eliminate the relation between sympathetic activity and organ damage. The aim of the present study is firstly to compare left ventricular mass (LVM) of CKD patients using chronic ACEi or an ARB with LVM of controls. Secondly, we determine whether previously found muscle sympathetic nerve activity (MSNA) and arterial blood pressure during follow-up are predictive for the presence of increased LVM. Methods. We restudied 20 CKD patients and 30 healthy volunteers matched for age. Sympathetic nerve activity was quantified by the microneurography (MSNA). Arterial blood pressure was the mean of office blood pressure measurements. LVM was quantified by magnetic resonance imaging (MRI) without contrast. RESULTS The period between MSNA and MRI measurements was 9 ± 3 years. All patients were treated according to guidelines with an ACEi or an ARB. In CKD patients, mean systolic and diastolic arterial pressure were 129 ± 10 and 84 ± 5 mmHg, respectively, during follow-up. In patients, as compared to controls, LVM was 93 ± 16 versus 76 ± 18 g, LVM index 30 ± 5 versus 24 ± 4 g/m(2.7) and mean wall thickness 11 ± 2 versus 9.0 ± 1 mm (all P < 0.01). Moreover, MSNA was related to LVM (r = 0.65, P < 0.002), LVM index (r = 0.46, P < 0.03) and LV mean wall thickness (r = 0.84, P < 0.001). Conclusions. In conclusion, the present study demonstrates that measures of LVM in CKD patients are greater than in healthy controls, despite a well-controlled blood pressure in the patients. Moreover, there is a positive relationship between these measures of LVM and MSNA, assessed years before, despite a standard antihypertensive treatment. These results support the notion that additional sympatholytic therapy could be beneficial.

Diagnostic value of imaging in infective endocarditis: a systematic review

Sensitivity and specificity of the modified Duke criteria for native valve endocarditis are both suboptimal, at approximately 80%. Diagnostic accuracy for intracardiac prosthetic material-related infection is even lower. Non-invasive imaging modalities could potentially improve diagnosis of infective endocarditis; however, their diagnostic value is unclear. We did a systematic literature review to critically appraise the evidence for the diagnostic performance of these imaging modalities, according to PRISMA and GRADE criteria. We searched PubMed, Embase, and Cochrane databases. 31 studies were included that presented original data on the performance of electrocardiogram (ECG)-gated multidetector CT angiography (MDCTA), ECG-gated MRI, 18F-fluorodeoxyglucose (18F-FDG) PET/CT, and leucocyte scintigraphy in diagnosis of native valve endocarditis, intracardiac prosthetic material-related infection, and extracardiac foci in adults. We consistently found positive albeit weak evidence for the diagnostic benefit of 18F-FDG PET/CT and MDCTA. We conclude that additional imaging techniques should be considered if infective endocarditis is suspected. We propose an evidence-based diagnostic work-up for infective endocarditis including these non-invasive techniques.

Head-to-head comparison between echocardiography and cardiac MRI in the evaluation of the athlete's heart

Objective Echocardiographic cut-off values are often used for cardiac MRI in athletic persons. This study investigates the difference between echocardiographic and cardiac MRI measurements of ventricular and atrial dimensions and ventricular wall thickness, and its effect on volume and wall mass prediction in athletic subjects compared with non-athletic controls. Methods Healthy non-athletic (59), regular athletic (59) and elite athletic (63) persons, aged 18–39 years and training 2.5±1.9, 13.0±3.0 and 25.0±5.4 h/week, respectively (p<0.001), underwent echocardiography and cardiac MRI consecutively. Left ventricular (LV) and right ventricular (RV) dimensions were measured on both modalities. LV and RV end-diastolic and end-systolic volumes and LV wall mass were determined on cardiac MRI. Echocardiographic M-mode LV volumes (Teichholz formula) and LV wall mass (American Society of Echocardiography formula) were calculated. Results LV and RV dimensions were smaller on echocardiography (p<0.001), and although the correlation with the cardiac MRI volume was good (p<0.01), the difference in volume was large (LV end-diastolic volume difference 93±32 g, p<0.001). LV wall thickness and calculated wall mass were significantly (p<0.001) larger on echocardiography (wall mass difference −101±34 g, p<0.001). Differences in absolute dimensions did not change significantly between non-athletic and athletic persons; however, the difference in echocardiographic estimations of LV volumes and wall mass did increase significantly with the larger athletes heart, requiring possible correction of the standard echocardiographic formulas. Conclusions Echocardiography shows systematically smaller atrial and ventricular dimensions and volumes, and larger wall thickness and mass, compared with cardiac MRI. Correction for the echocardiographic formulas can facilitate better intertechnique comparability. These findings should be taken into account in the interpretation of cardiac MRI findings in athletic subjects in whom cardiomyopathy is suspected on echocardiography.

Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes.

Background: Higher levels of physical activity are associated with a lower risk of cardiovascular events. Nevertheless, there is debate on the dose-response relationship of exercise and cardiovascular disease outcomes and whether high volumes of exercise may accelerate coronary atherosclerosis. We aimed to determine the relationship between lifelong exercise volumes and coronary atherosclerosis. Methods: Middle-aged men engaged in competitive or recreational leisure sports underwent a noncontrast and contrast-enhanced computed tomography scan to assess coronary artery calcification (CAC) and plaque characteristics. Participants reported lifelong exercise history patterns. Exercise volumes were multiplied by metabolic equivalent of task (MET) scores to calculate MET-minutes per week. Participants’ activity was categorized as <1000, 1000 to 2000, or >2000 MET-min/wk. Results: A total of 284 men (age, 55±7 years) were included. CAC was present in 150 of 284 participants (53%) with a median CAC score of 35.8 (interquartile range, 9.3–145.8). Athletes with a lifelong exercise volume >2000 MET-min/wk (n=75) had a significantly higher CAC score (9.4 [interquartile range, 0–60.9] versus 0 [interquartile range, 0–43.5]; P=0.02) and prevalence of CAC (68%; adjusted odds ratio [ORadjusted]=3.2; 95% confidence interval [CI], 1.6–6.6) and plaque (77%; ORadjusted=3.3; 95% CI, 1.6–7.1) compared with <1000 MET-min/wk (n=88; 43% and 56%, respectively). Very vigorous intensity exercise (≥9 MET) was associated with CAC (ORadjusted=1.47; 95% CI, 1.14–1.91) and plaque (ORadjusted=1.56; 95% CI, 1.17–2.08). Among participants with CAC>0, there was no difference in CAC score (P=0.20), area (P=0.21), density (P=0.25), and regions of interest (P=0.20) across exercise volume groups. Among participants with plaque, the most active group (>2000 MET-min/wk) had a lower prevalence of mixed plaques (48% versus 69%; ORadjusted=0.35; 95% CI, 0.15–0.85) and more often had only calcified plaques (38% versus 16%; ORadjusted=3.57; 95% CI, 1.28–9.97) compared with the least active group (<1000 MET-min/wk). Conclusions: Participants in the >2000 MET-min/wk group had a higher prevalence of CAC and atherosclerotic plaques. The most active group, however, had a more benign composition of plaques, with fewer mixed plaques and more often only calcified plaques. These observations may explain the increased longevity typical of endurance athletes despite the presence of more coronary atherosclerotic plaque in the most active participants.

The Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes.

Background: Higher levels of physical activity are associated with a lower risk of cardiovascular events. Nevertheless, there is debate on the dose-response relationship of exercise and cardiovascular disease outcomes and whether high volumes of exercise may accelerate coronary atherosclerosis. We aimed to determine the relationship between lifelong exercise volumes and coronary atherosclerosis. Methods: Middle-aged men engaged in competitive or recreational leisure sports underwent a noncontrast and contrast-enhanced computed tomography scan to assess coronary artery calcification (CAC) and plaque characteristics. Participants reported lifelong exercise history patterns. Exercise volumes were multiplied by metabolic equivalent of task (MET) scores to calculate MET-minutes per week. Participants’ activity was categorized as <1000, 1000 to 2000, or >2000 MET-min/wk. Results: A total of 284 men (age, 55±7 years) were included. CAC was present in 150 of 284 participants (53%) with a median CAC score of 35.8 (interquartile range, 9.3–145.8). Athletes with a lifelong exercise volume >2000 MET-min/wk (n=75) had a significantly higher CAC score (9.4 [interquartile range, 0–60.9] versus 0 [interquartile range, 0–43.5]; P=0.02) and prevalence of CAC (68%; adjusted odds ratio [ORadjusted]=3.2; 95% confidence interval [CI], 1.6–6.6) and plaque (77%; ORadjusted=3.3; 95% CI, 1.6–7.1) compared with <1000 MET-min/wk (n=88; 43% and 56%, respectively). Very vigorous intensity exercise (≥9 MET) was associated with CAC (ORadjusted=1.47; 95% CI, 1.14–1.91) and plaque (ORadjusted=1.56; 95% CI, 1.17–2.08). Among participants with CAC>0, there was no difference in CAC score (P=0.20), area (P=0.21), density (P=0.25), and regions of interest (P=0.20) across exercise volume groups. Among participants with plaque, the most active group (>2000 MET-min/wk) had a lower prevalence of mixed plaques (48% versus 69%; ORadjusted=0.35; 95% CI, 0.15–0.85) and more often had only calcified plaques (38% versus 16%; ORadjusted=3.57; 95% CI, 1.28–9.97) compared with the least active group (<1000 MET-min/wk). Conclusions: Participants in the >2000 MET-min/wk group had a higher prevalence of CAC and atherosclerotic plaques. The most active group, however, had a more benign composition of plaques, with fewer mixed plaques and more often only calcified plaques. These observations may explain the increased longevity typical of endurance athletes despite the presence of more coronary atherosclerotic plaque in the most active participants.

Occult coronary artery disease in middle-aged sportsmen with a low cardiovascular risk score: The Measuring Athlete's Risk of Cardiovascular Events (MARC) study.

Background Most exercise-related cardiac arrests in men aged ≥45 years are due to coronary artery disease (CAD). The current sports medical evaluation (SME) of middle-aged sportsmen includes medical history, physical examination and resting and exercise electrocardiography (ECG). We investigated the added value of low-dose cardiac computed tomography (CCT) – both non-contrast CT for coronary artery calcium scoring (CACS) and contrast-enhanced coronary CT angiography (CCTA) – in order to detect occult CAD in asymptomatic recreational sportsmen aged ≥45 years without known cardiovascular disease. Methods Following a normal SME (with resting and bicycle exercise ECG), 318 asymptomatic sportsmen underwent CCT and 300 (94%) had a low European Society of Cardiology Systematic Coronary Risk Evaluation (SCORE) risk. Occult CAD was defined as a CACS ≥100 Agatston units (AU) or obstructive (≥50%) luminal stenosis on CCTA. The number needed to screen (NNS) in order to prevent one cardiovascular event within 5 years with statin treatment was estimated. Results Fifty-two (16.4%, 95% confidence interval (CI): 12.7–20.8%) of 318 participants had a CACS ≥100 AU. The CCTA identified an additional eight participants with luminal narrowing ≥50% (and a CACS <100 AU). Taken together, CCT identified CAD in 60 (18.9%, 95% CI: 14.9–23.5%) of 318 participants. The 5-year estimated NNS was 183 (95% CI: 144–236) for CACS and 159 (95% CI: 128–201) for CACS combined with CCTA. Conclusions Coronary CT detects occult CAD in almost one in five asymptomatic sportsmen aged ≥45 years after a normal SME that included resting and bicycle exercise ECG. CACS reveals most of the relevant CAD with limited additional value of contrast-enhanced CCTA. The NNS in order to prevent one cardiovascular event compares favourably to that of other screening tests.

Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation

Technological advances in magnetic resonance imaging (MRI) and computed tomography (CT), including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET). This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD), as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings.

Quantitative myocardial perfusion evaluation with positron emission tomography and the risk of cardiovascular events in patients with coronary artery disease: A systematic review of prognostic studies

Abstract Aims To evaluate the prognostic value of quantitative myocardial perfusion imaging with positron emission tomography (PET) for adverse cardiovascular outcomes in patients with known or suspected coronary artery disease (CAD). Methods and results A search in MEDLINE and Embase was conducted for studies that evaluated (i) myocardial perfusion in absolute terms with PET, (ii) prognostic value for the development of major adverse cardiovascular events (MACE), cardiac death, and/or all-cause mortality, and (iii) patients with known or suspected CAD. Studies were divided according to the radiotracer utilized and their included population (patients with and without previous infarction). Comprehensive description and a selected instance of pooling were performed. Eight studies (n = 6804) were analysed and documented clear variability in population, quantitative PET variables operationalization [stress myocardial blood flow (sMBF) and flow reserve (MFR)], statistical covariate structure, follow-up, and radiotracer utilized. MFR was independently associated with MACE in eight studies [range of adjusted hazard ratios (HRs): 1.19–2.93]. The pooling instance demonstrated that MFR significantly associates with the development of MACEs (HR: 1.92 [1.29, 2.84]; P = 0.001). sMBF was only associated with MACE in two studies that evaluated it, and only one study documented sMBF as a better predictor than MFR. Conclusion This systematic review demonstrates the prognostic value of quantitative myocardial perfusion evaluated with PET, in the form of MFR and sMBF, for the development of major adverse cardiovascular outcomes in populations with known or suspected CAD. In the qualitative comparison, MFR seems to outperform sMBF as an independent prognostic factor. Evidence is still lacking for assessing quantitative PET for the occurrence of cardiac death and all-cause mortality. There is clear heterogeneity in predictor operationalization and study performances.

Intermodel Agreement of Myocardial Blood Flow Estimation From Stress-Rest Myocardial Perfusion Magnetic Resonance Imaging in Patients With Coronary Artery Disease

ObjectivesThe aim of this study was to assess the intermodel agreement of different magnetic resonance myocardial perfusion models and evaluate their correspondence to stenosis diameter. Materials and MethodsIn total, 260 myocardial segments were analyzed from rest and adenosine stress first-pass myocardial perfusion magnetic resonance images (1.5 T, 0.050 ± 0.005 mmol/kg body weight gadolinium; 122 segments in rest, 138 in stress) in 10 patients with suspected or known coronary artery disease. Signal intensity curves were calculated per myocardial segment, of which the contours were traced with QMASS MR V.7.6 (Medis, Leiden, the Netherlands), and exported to Matlab. Myocardial blood flow quantification was performed with distributed parameter, extended Toft, Patlak, and Fermi parametric models (in-house programs; Matlab R2013a; Mathworks Inc, Natick, MA). Modeling was applied after the signal intensity curves were corrected for spatial magnetic field inhomogeneity and contrast saturation. Overall and grouped perfusion values based on presence of coronary stenosis (>50% diameter reduction) at coronary computed tomography angiography at second generation dual-source computed tomography were compared between the perfusion models. ResultsRest and stress myocardial perfusion estimates for all models were significantly related to each other (P < 0.001). The highest correlation coefficients were found between the extended Toft and Fermi models (R = 0.89−0.91) and low correlation coefficients between the distributed parameter and Patlak models (R = 0.66−0.68). The models resulted in significantly different perfusion estimates in stress (P = 0.03), but not in rest (P = 0.74). The differences in perfusion estimates in stress were caused by differences between the distributed parameter and Patlak models and between the Patlak and Fermi models (both P < 0.001). Significantly lower perfusion estimates were found for myocardial segments subtended by coronary arteries with versus without significant stenosis, but only for estimations produced by the extended Toft model (P = 0.04) and Fermi model (P = 0.01). There were no significant differences in rest perfusion values between models. ConclusionsQuantitative myocardial perfusion values in stress depend on the modeling method used to calculate the perfusion estimate. The difference in myocardial perfusion estimate with or without stenosis in the subtending coronary artery is most pronounced when the extended Toft or Fermi model is used.