Christian Meierhofer

Wall shear stress and flow patterns in the ascending aorta in patients with bicuspid aortic valves differ significantly from tricuspid aortic valves: a prospective study.

AIMS We compared flow and wall shear stress (WSS) patterns in the ascending aorta of individuals with either bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) using four-dimensional cardiovascular magnetic resonance (4D-CMR). BAV are known to be associated with dilation and dissection of the ascending aorta. However, the cause of vessel disease in patients with BAVs is unknown. Inborn connective tissue disease and also dilation secondary to increased WSS because of altered blood flow patterns in the ascending aorta are discussed as causes for dilation of the aorta. WSS can be estimated non-invasively by 4D-CMR. METHODS AND RESULTS Eighteen, otherwise, healthy individuals with functionally normal BAVs were compared prospectively with an age- and sex-matched control group of healthy individuals with TAV. Blood flow data were obtained by 4D-CMR visualization and WSS was calculated with specific software tools. Eighty-five per cent of the individuals with BAVs showed a high-grade helical flow pattern in the ascending aorta compared with 6% of the individuals with TAV. WSS in the ascending aorta was significantly altered in individuals with BAVs compared with TAV. CONCLUSION WSS and flow patterns in the ascending aorta in patients with BAVs without concomitant valve or vessel disease are significantly different compared with TAV. The significantly higher shear forces may have an impact on the development of aortic dilation in patients with BAVs.

Non-volumetric echocardiographic indices and qualitative assessment of right ventricular systolic function in Ebstein's anomaly: comparison with CMR-derived ejection fraction in 49 patients

AIMS Ebsteins anomaly (EA) is often associated with right ventricular (RV) dysfunction. Data on echocardiographic quantification of RV function are, however, rare. The aim of this study was to determine how non-volumetric echocardiographic indices and qualitative assessment of global systolic RV function correlate with cardiovascular magnetic resonance (CMR)-derived RV ejection fraction (EF). METHODS AND RESULTS We compared six echocardiographic indices and qualitative assessment of RV function with the gold standard CMR. A total of 49 unoperated patients with EA and a mean age of 32 ± 18 years were examined. Tricuspid annular plane systolic excursion, tissue Doppler myocardial velocities (peak S and IVA) and 2D strain and strain rate measures for the RV were compared with CMR-derived EF. Only 2D global longitudinal strain (2D-GLS), out of the six parameters investigated, showed a weak, although statistically significant correlation with CMR-derived RVEF (R = -0.4, P = 0.01). Using a cut-off value of -20.15, 2D-GLS sensitivity (77%) and specificity (46%) in detecting patients with a CMR-derived EF of <50% were comparable with qualitative assessment (sensitivity 77%, specificity 45%). CONCLUSION Overall echocardiographic parameters of RV function correlate poorly with CMR-derived EF in patients with EA. Only 2D global longitudinal RV strain correlated weakly with CMR-derived RVEF. However, the sensitivity and specificity for detecting RV dysfunction using 2D strain imaging were comparable with qualitative RV functional assessment.

Myocardial blood flow in patients with transposition of the great arteries - risk factor for dysfunction of the morphologic systemic right ventricle late after atrial repair.

BACKGROUND Dysfunction of the morphologic systemic right ventricle (RV) is a sequela in long-term survivors with transposition of the great arteries (TGA) after atrial switch operation (AtSO). Impairment of myocardial blood flow (MBF) and coronary flow reserve (CFR) are hypothesized as predisposing factors. METHODS AND RESULTS The study group comprised 20 patients after AtSO (22.7 ± 5.03 years) and 15 individuals with congenitally corrected transposition (ccTGA) (30.6 ± 19.4 years). MBF was quantified by positron emission tomography; controls for coronary flow were 11 healthy volunteers (26.2 ± 5.1 years). Exercise capacity, ventricular mass, function and end-diastolic volume assessed by coronary magnetic resonance (CMR), hemodynamic parameters assessed by cardiac catheterization and echocardiography, and B-type natriuretic peptide levels correlated with MBF. At rest, MBF did not differ between patients and healthy volunteers (MBFrestml·100 g(-1)·min(-1); ccTGA: 75 ± 14 vs. AtSO: 73 ± 16 vs. controls: 77 ± 15; NS). After vasodilatation, MBF increased significantly, but was significantly lower in ccTGA and AtSO groups compared with controls (MBFstressml·100 g(-1)·min(-1); ccTGA: 198 ± 38 vs. AtSO: 167 ± 46 vs. controls 310 ± 74; P<0.001). In ccTGA, CFR correlated significantly with clinical, CMR, echocardiographic and hemodynamic parameters, but for AtSO patients no significant correlation could be calculated. CONCLUSIONS In patients with ccTGA, maximal coronary blood flow is attenuated and significantly correlated with ventricular function, whereas dysfunction of the morphologic systemic RV after AtSO is a multifactorial problem.

Baseline correction does not improve flow quantification in phase-contrast velocity measurement for routine clinical practice

INTRODUCTION Velocity offset errors may influence flow measurement in phase-contrast cardiovascular magnetic resonance (CMR). By using a stationary gel phantom, offset errors probably may be corrected. We tested its impact on flow measurement and, in particular, on shunt calculation in patients proven not to have any shunt. METHODS Flow measurements were carried out in 24 patients with congenital heart disease. Baseline correction was performed by using a stationary gel phantom. RESULTS Significantly more patients without shunts incorrectly showed a calculated shunt after baseline correction. CONCLUSIONS Baseline correction did not improve flow measurement and was clinically not relevant for routine CMR.

Physical exercise reduces aortic regurgitation: exercise magnetic resonance imaging.

In patients with aortic regurgitation (AR), exercise testing plays a pivotal role in clinical decision making according to American College of Cardiology/American Heart Association guidelines. However, it is unclear exactly how AR behaves during exercise, as it has only been estimated but not

Repeat Routine Differential Pulmonary Blood Flow Measurements in Congenital Heart Disease by MR: Interstudy Variability and Benchmark of a Clinically Relevant Change.

Phase-velocity magnetic resonance (PV-MR) quantifies differential pulmonary blood flow as accurately as the previous gold standard lung perfusion scintigraphy in patients with a single pulmonary blood source supplied by a subpulmonary ventricle ([1–3][1]). Therefore, in routine clinical practice,

How Late Is Too Late? Giant Balloon-like Aneurysm of the Ascending Aorta

A 26-year-old woman with Turner syndrome, bicuspid aortic valve, and aortic coarctation was referred due to recurrent chest pain. Aortic coarctation had been bypassed with an extra-anatomic GORE-TEX (W.L. Gore & Associates, Inc., Flagstaff, Ariz) graft. The patient developed an aneurysm of the ascending aorta and a coarctation restenosis. At the age of 15 years, operative repair of the growing aortic aneurysm (70 mm) was proposed but declined by the patient, who defied further controls. At presentation, physical examination revealed characteristic features of Turner syndrome (weight 61 kg, length 146 cm, body surface area 1.5 m). Blood pressure in the right arm was 166/95 mm Hg, with an upper-lower extremity gradient of 30 mm Hg. The patient had no medication. Echocardiography and cardiac magnetic resonance imaging showed a giant aneurysm of the ascending aorta. The diameter of the aneurysm was 100 mm 120 mm, with a small dissection membrane (Figures 1, 2). In addition, the connection between the ascending aortic aneurysm and the GORE-TEX graft was stenotic. Because of high risk for acute aortic rupture, a Bentall procedure with replacement of the ascending aorta and implantation of a mechanical aortic valve was performed. The conduit between the ascending and descending aorta was reinserted into the prosthesis of the ascending aorta. The operation was successful despite complications with prolonged operation time (465 minutes) due to extended adhesions and diffuse bleeding. Histological analysis of the aortic aneurysm showed myxoid degeneration of the media layer and intimal fibrosis. The postoperative period was complicated by a hematoma in the cavity between the new ascending aorta and the remaining parts of the old aneurysm wall. Moreover, anti-

Comparison of MR flow quantification in peripheral and main pulmonary arteries in patients after right ventricular outflow tract surgery: A retrospective study: MR Flow Measurements in RVOT Pathologies

To compare the quantification of pulmonary stroke volume (SV) by phase contrast magnetic resonance (PC‐MR) in the main pulmonary artery (MPA) to the sum of SVs in both peripheral pulmonary arteries (PPA) in different right ventricular (RV) outflow pathologies.

Cardiac volumes can be quantified accurately during free-breathing in young patients with congenital heart disease by cardiovascular magnetic resonance

Background Cardiovascular Magnetic Resonance (CMR) with respiratory commands is the gold standard technique to measure cardiac volumes. Although cardiac volumes can be measured during free breathing in patients with congenital heart disease (CHD), its accuracy is unknown. Therefore, the aim of this study was to compare cardiac volumes acquired during free breathing with volumes acquired during breath hold commands.

Cardiovascular magnetic resonance is feasible in many patients aged 3 to 8 years without general anesthesia or sedation

Background Cardiovascular Magnetic Resonance (CMR) of pediatric patients has become routine clinical practice. Patients under eight years are usually examined under general anesthesia (GA) or sedation without intubation. However, in our clinical experience, CMR may be feasible in patients aged 3 to 8 years without general anesthesia or sedation without intubation. Methods Retrospectively studied datasets of total number of 71 patients aged between 3 and 8 years. The total cohort was divided into two groups, first with no general anesthesia or sedation without intubation (no GA or sedation) and the second group patients with general anesthesia or sedation without intubation (GA or sedation). The patients’ age groups and scan durations for each group, percentage of successfully answering the clinical question in each group, total number of scanned sequences in each group, and number of sequences per study were recorded and compared between both groups. Results Forty-four patients in the no GA or sedation group, 27 in the GA or sedation group. The scan duration was in the no GA or sedation group: 35 minutes ± 20.44 minutes, and in the GA or sedation group: 60 minutes ± 31 minutes (p < 0.001). The percentage of successful reports was 95% (42 of 44) in the no GA or sedation group and 89% (24 of 27) in the patients with GA or sedation group. Conclusions In scope of understanding the CHD hemodynamics, and clinical requests and questions; the decision of using neither general anesthesia with intubation nor sedation with without intubation was favored by our center’s CMR unit over examining the patients under general anesthesia or sedation, to avoid the effect of general anesthesia and sedation on cardiac function during CMR, decrease the CMR scan duration, and increase the feasibility of the CMR in the young age group between three and eight years. Funding