Cardiac function by MRI in congenital heart disease: impact of consensus training on interinstitutional variance.
ABSTRACT To investigate the impact of interinstitutional variance (=interobserver variance between institutions) for volumetric and flow cardiac MR (CMR) data and if training on image reading could improve bias.
In a three-center study, a total of 32 adults with repaired Tetralogy of Fallot and 23 controls underwent CMR using standardized protocols for ventricular volumes/mass (by transverse and short-axis cine-MRI) and pulmonary/aortic blood flow by velocity-encoded MRI (VEC-MRI). Data were analyzed blinded and independently in each institution by experienced readers. Interinstitutional variance was determined before/after training on consented guidelines for image analysis.
In patients, initial interinstitutional variability of right ventricular parameters was substantial but decreased by training. On transverse planes, variation coefficient for end-diastolic/systolic volumes and ejection fraction decreased from 22%, 19%, and 19% to 7%, 10%, and 8%, respectively (P < 0.025). Left-ventricular variation coefficients improved for end-diastolic and stroke volumes from 8% and 15% to 4% and 6%, respectively (P < 0.007). For short-axis volumetry training resulted in narrowed limits of confidence. Variability did not significantly change in the controls. There was no significant difference between transverse/short-axis MRI. Interinstitutional variance for VEC-MRI in patients/controls was low (<4%).
Interinstitutional variance is an important source of variability in volumetric but not in flow CMR. Such variance can be reduced effectively by consented training.
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ABSTRACT: The timing of pulmonary valve replacement (PVR) for free pulmonary incompetence in patients with congenital heart disease remains a dilemma for clinicians. We wanted to assess the determinants of improvement after PVR for pulmonary regurgitation over a wide range of patient ages and to use any identified predictors to compare clinical outcomes between patient groups. Seventy-one patients (mean age 22+/-11 years; range, 8.5 to 64.9; 72% tetralogy of Fallot) underwent PVR for severe pulmonary regurgitation. New York Heart Association class improved after PVR (median of 2 to 1, P<0.0001). MRI and cardiopulmonary exercise testing were performed before and 1 year after intervention. After PVR, there was a significant reduction in right ventricular volumes (end diastolic volume 142+/-43 to 91+/-18, end systolic volume 73+/-33 to 43+/-14 mL/m(2), P<0.0001), whereas left ventricular end diastolic volume increased (66+/-12 to 73+/-13 mL/m(2), P<0.0001). Effective cardiac output significantly increased (right ventricular: 3.0+/-0.8 to 3.3+/-0.8 L/min, P=0.013 and left ventricular: 3.0+/-0.6 to 3.4+/-0.7 L/min, P<0.0001). On cardiopulmonary exercise testing, ventilatory response to carbon dioxide production at anaerobic threshold improved from 35.9+/-5.8 to 34.1+/-6.2 (P=0.008). Normalization of ventilatory response to carbon dioxide production was most likely to occur when PVR was performed at an age younger than 17.5 years (P=0.013). A relatively aggressive PVR policy (end diastolic volume <150 mL/m(2)) leads to normalization of right ventricular volumes, improvement in biventricular function, and submaximal exercise capacity. Normalization of ventilatory response to carbon dioxide production is most likely to occur when surgery is performed at an age </=17.5 years. This is also associated with a better left ventricular filling and systolic function after surgery.Circulation 10/2008; 118(14 Suppl):S182-90. · 15.20 Impact Factor
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ABSTRACT: Correct timing of pulmonary valve replacement (PVR) is crucial for preventing complications of pulmonary regurgitation and right ventricular (RV) dilatation after repair of tetralogy of Fallot. We sought to assess the remodelling of the RV after early PVR in children, using cardiovascular magnetic resonance (CMR). Twenty children with severe pulmonary regurgitation and RV dilatation and mean age 13.9 +/- 3 years underwent CMR evaluation 5.6 +/- 1.8 months before and 5.9 +/- 0.6 months after PVR. PVR was performed when the RV end-diastolic volume exceeded 150 mL/m(2), as measured by CMR. The time interval between primary repair and PVR was 12 +/- 3 years. Post-operative CMR demonstrated a significant reduction of the RV end-diastolic volume from 189.8 +/- 33.4 to 108.7 +/- 25.8 mL/m(2) (P < 0.0001), of the RV end-systolic volume from 102.4 +/- 27.3 to 58.2 +/- 16.3 mL/m(2) (P < 0.0001), and of the RV mass from 48.7 +/- 12.3 to 35.8 +/- 7.7 g/m(2) (P < 0.0001). The RV ejection fraction did not change significantly. Prompt RV remodelling, with reduction of RV volume and mass, is observed after performing PVR if the RV end-diastolic volume exceeds 150 mL/m(2). Early PVR may prevent the detrimental complications of severe pulmonary regurgitation.European Heart Journal 12/2005; 26(24):2721-7. · 14.10 Impact Factor
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ABSTRACT: To determine the degree of inter-institutional agreement in the assessment of dobutamine stress echocardiograms using modern stress echocardiographic technology in combination with standardized data acquisition and assessment criteria. Among six experienced institutions, 150 dobutamine stress echocardiograms (dobutamine up to 40 microg x kg(-1) min(-1) and atropine up to 1 mg) were performed on patients with suspected coronary artery disease using fundamental and harmonic imaging following a consistent digital acquisition protocol. Each dobutamine stress echocardiogram was assessed at every institution regarding endocardial visibility and left ventricular wall motion without knowledge of any other data using standardized reading criteria. No patients were excluded due to poor image quality or inadequate stress level. Coronary angiography was performed within 4 weeks. Coronary angiography demonstrated significant coronary artery disease (> or = 50% diameter stenosis) in 87 patients. Using harmonic imaging an average of 5.2+/-0.9 institutions agreed on dobutamine stress echocardiogram results as being normal or abnormal (mean kappa 0.55; 95% CI 0.50-0.60). Agreement was higher in patients with no (equal assessment of dobutamine stress echocardiogram results by 5.5+/-0.8 institutions) or three-vessel coronary artery disease (5.4+/- 0.8 institutions) and lower in one- or two- vessel disease (5.0+/-0.9 and 5.2+/-1.0 institutions, respectively; P=0.041). Disagreement on test results was greater in only minor wall motion abnormalities. Agreement on dobutamine stress echocardiogram results was lower using fundamental imaging (mean kappa 0.49; 95% CI 0.44-0.54; P<0.01 vs harmonic imaging). Modern echocardiographic technology in combination with standardized digital image processing and uniform reading criteria results in a higher inter-institutional agreement in the interpretation of dobutamine stress echocardiogram compared to historic reports.European Heart Journal 06/2002; 23(10):821-9. · 14.10 Impact Factor