Arni Nutting

Effect of Branch Pulmonary Artery Stenosis on Right Ventricular Volume Overload in Patients With Tetralogy of Fallot After Initial Surgical Repair

Right ventricular (RV) volume overload secondary to pulmonary regurgitation is common in patients after initial repair of tetralogy of Fallot (TOF) and is associated with adverse long-term outcomes. The objective of the present study was to determine the effect of branch pulmonary artery stenosis on the RV volume in patients with repaired TOF. We reviewed 178 cardiac magnetic resonance imaging studies in patients with repaired TOF. We defined bilateral stenosis as a Nakata index of ≤200 mm(2)/m(2) and concordant branch pulmonary artery cross-sectional area, unilateral stenosis as 1 branch pulmonary artery cross-sectional area ≤100 mm(2)/m(2) and 1 branch pulmonary artery cross-sectional area >100 mm(2)/m(2), and restrictive physiology as prograde main pulmonary artery diastolic flow. Of the 178 patients, 20 (11%) had bilateral stenosis, 47 (26%) unilateral stenosis, and 111 (63%) had no stenosis. The RV end-diastolic volume was lower in patients with bilateral (125 ± 27 ml/m(2)) or unilateral (131 ± 43 ml/m(2)) stenosis than in those without stenosis (149 ± 35 ml/m(2), p = 0.021 and p = 0.019, respectively). The main pulmonary artery regurgitant fraction was greater in patients without stenosis (47%, range 2% to 69%) than in those with bilateral (33%, range 9% to 59%; p = 0.009) or unilateral stenosis (40%, range 0% to 71%; p = 0.033). Restrictive physiology was more common in patients with bilateral (13 of 15, 87%) or unilateral (21 of 38, 55%) stenosis than in those without stenosis (28 of 85, 33%; p <0.001 and p = 0.017, respectively). In conclusion, in patients with repaired TOF, bilateral and unilateral branch pulmonary artery stenosis was associated with a greater main pulmonary artery regurgitant fraction and smaller RV end-diastolic volume than those in patients without stenosis, likely owing to the development of restrictive physiology. Branch pulmonary artery stenosis might effectively delay the referral for pulmonary valve replacement.

Impact of Obesity on Ventricular Size and Function in Children, Adolescents and Adults With Tetralogy of Fallot After Initial Repair

Obesity is epidemic in congenital heart disease, with reported rates of 16% to 26% in children and 54% in adults. The aim of this study was to evaluate the impact of obesity on ventricular function and size in patients after initial repair for tetralogy of Fallot (TOF). Cardiac magnetic resonance studies in normal-weight (body mass index percentile <85th) and obese (body mass index percentile ≥95th) children and adults with repaired tetralogy of Fallot were reviewed. The left ventricular ejection fraction, the right ventricular ejection fraction, left and right ventricular end-diastolic volumes indexed to actual body surface area, to height, and to body surface area using ideal body weight were evaluated in 36 obese patients and 72 age-matched normal-weight patients. Compared with normal-weight patients, obese patients had lower right ventricular ejection fractions (mean 46 ± 9% vs 51 ± 7%, p = 0.003) and left ventricular ejection fractions (mean 57 ± 9% vs 61 ± 6%, p = 0.017), higher right ventricular end-diastolic volumes indexed to height (mean 160 ± 59 vs 135 ± 41 ml/m, p = 0.015) and left ventricular end-diastolic volumes indexed to height (mean 86 ± 25 vs 70 ± 20 ml/m, p = 0.001), and higher right ventricular end-diastolic volumes indexed to ideal body weight (mean 166 ± 55 vs 144 ± 38 ml/m², p = 0.020) and left ventricular end-diastolic volumes indexed to ideal body weight (mean 90 ± 22 vs 75 ± 15 ml/m², p <0.001). In conclusion, obesity is a modifiable risk factor associated with worsened biventricular systolic function and biventricular dilation in patients with repaired tetralogy of Fallot. The standard method of indexing ventricular volumes using actual body surface area may underestimate volume load in obese patients.

Coronary artery assessment using self-navigated free-breathing radial whole-heart magnetic resonance angiography in patients with congenital heart disease

ObjectivesTo evaluate a self-navigated free-breathing three-dimensional (SNFB3D) radial whole-heart MRA technique for assessment of main coronary arteries (CAs) and side branches in patients with congenital heart disease (CHD).MethodsSNFB3D-MRA datasets of 109 patients (20.1±11.8 years) were included. Three readers assessed the depiction of CA segments, diagnostic confidence in determining CA dominance, overall image quality and the ability to freeze cardiac and respiratory motion. Vessel sharpness was quantitatively measured.ResultsThe percentages of cases with excellent CA depiction were as follows (mean score): left main, 92.6 % (1.92); left anterior descending (LAD), 88.3 % (1.88); right (RCA), 87.8 % (1.85); left circumflex, 82.8 % (1.82); posterior descending, 50.2 % (1.50) and first diagonal, 39.8 % (1.39). High diagnostic confidence for the assessment of CA dominance was achieved in 56.2 % of MRA examinations (mean score, 1.56). Cardiac motion freezing (mean score, 2.18; Pearson’s r=0.73, P<0.029) affected image quality more than respiratory motion freezing (mean score, 2.20; r=0.58, P<0.029). Mean quantitative vessel sharpness of the internal thoracic artery, RCA and LAD were 53.1, 52.5 and 48.7 %, respectively.ConclusionsMost SNFB3D-MRA examinations allow for excellent depiction of the main CAs in young CHD patients; visualisation of side branches remains limited.Key Points• Self-navigated free-breathing three-dimensional magnetic resonance angiography (SNFB3D-MRA) sufficiently visualises coronary arteries (CAs).• Depiction of main CAs in patients with congenital heart disease is excellent.• Visualisation of CA side branches using SNFB3D-MRA is limited.• SNFB3D-MRA image quality is especially correlated to cardiac motion freezing ability.

Longitudinal measures of deformation are associated with a composite measure of contractility derived from pressure–volume loop analysis in children

Aims The relationship between echocardiographic measures of left ventricular (LV) systolic function and reference-standard measures have not been assessed in children. The objective of this study was to assess the validity of echocardiographic indices of LV systolic function via direct comparison to a novel composite measure of contractility derived from pressure-volume loop (PVL) analysis. Methods and results Children with normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. A composite invasive composite contractility index (ICCI) was developed using data reduction strategies to combine four measures of contractility derived from PVL analysis. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Conventional and speckle-tracking echocardiographic measures of systolic function were measured. Of 24 patients, 18 patients were heart transplant recipients, 6 patients had a small patent ductus arteriosus or small coronary fistula. Mean age was 9.1 ± 5.6 years. Upon multivariable regression, longitudinal strain was associated with ICCI (β = -0.54, P = 0.02) while controlling for indices of preload, afterload, heart rate, and LV mass under baseline conditions. Ejection fraction and shortening fraction were associated with LV mass and load indices, but not contractility. Conclusion Speckle-tracking derived longitudinal strain is associated ICCI in children with normal loading conditions. Longitudinal measures of deformation appear to accurately assess LV contractility in children.

Utility of cardiac magnetic resonance imaging in the management of adult congenital heart disease

The increasing number of patients with adult congenital heart disease (ACHD) calls for the development of noninvasive imaging techniques that allow a long-term evaluation of native and postsurgical anatomy and function. Echocardiography remains the imaging modality of choice for congenital heart disease, but it is affected by limited acoustic windows and poor tissue characterization. Cardiac computed tomography and cardiac catheter angiography are 2 valid alternatives for the anatomic and functional assessment of ACHD; however, both use ionizing radiation, and cardiac catheter angiography requires an invasive approach. Cardiac magnetic resonance (CMR), noninvasively and in the absence of ionizing radiation, has the ability to evaluate the biventricular function, quantify flows, characterize tissue, and provide information on cardiac anatomy. Despite the long acquisition time and lower spatial resolution compared with cardiac computed tomography, CMR represents the ideal technique for long-term follow-up of ACHD. CMR is now widely utilized and is well described in the literature with regard to diagnosis, identification of complications, timing of surgery, and postoperative prognosis in ACHD. CMR represents a fundamental technique for the evaluation of patients with ACHD.

Echocardiographic Detection of Increased Ventricular Diastolic Stiffness in Pediatric Heart Transplant Recipients: A Pilot Study

Background: Pediatric heart transplant recipients are at risk for increased left ventricular (LV) diastolic stiffness. However, the noninvasive evaluation of LV stiffness has remained elusive in this population. The objective of this study was to compare novel echocardiographic measures of LV diastolic stiffness versus gold‐standard measures derived from pressure‐volume loop (PVL) analysis in pediatric heart transplant recipients. Methods: Patients undergoing left heart catheterization were prospectively enrolled. PVLs were obtained via conductance. The end‐diastolic pressure‐volume relationship was obtained via balloon occlusion. The stiffness constant, &bgr;, was calculated. Echocardiographic measures of diastolic function were derived from spectral and tissue Doppler and two‐dimensional speckle‐tracking. Ventricular volumes were measured using three‐dimensional echocardiography. The novel echocardiographic estimates of ventricular stiffness included E:e′/end‐diastolic volume (EDV) and E:early diastolic strain rate/EDV. Results: Of 24 children, 18 were heart transplant recipients. Six control patients had hemodynamically insignificant patent ductus arteriosus or coronary fistula. The mean age was 9.1 ± 5.6 years. Median end‐diastolic pressure was 9 mm Hg (interquartile range, 8–13 mm Hg). Lateral E:e′/EDV (r = 0.59, P < .01), septal E:e′/EDV (r = 0.57, P < .01), and (E:circumferential early diastolic strain rate)/EDV (r = 0.54, P < .01) correlated with &bgr;. Lateral E:e′/EDV displayed a C statistic of 0.93 in detecting patients with abnormal LV stiffness (&bgr; > 0.015 mL−1). A lateral E:e′/EDV of >0.15 mL−1 had 89% sensitivity and 93% specificity in detecting an abnormal &bgr;. Conclusions: Echocardiographic estimates of ventricular stiffness may be accurate compared with the gold standard in pediatric heart transplant recipients. The clinical usefulness of these noninvasive measures in assessing LV stiffness merits further study in children.

Single center experience with a prototype self-navigated 3D SSFP whole heart sequence in assessing coronary artery origin

Background This prototype, self navigated, free breathing 3D sequence acquires continuous ECG-segmented radial views of the heart with 100% scan efficiency, without a beam-navigator, and without the time expense of scanning within a range of diaphragmatic positions. The reconstructed image is respiratory motion corrected based on the inferior-superior motion of the left ventricular blood pool. Acquisition times are typically 5-6 minutes. This is a retrospective review to determine the sensitivity of diagnosing coronary origins and to describe some factors affecting image quality.