Impaired regional left ventricular strain after repair of tetralogy of Fallot.

PURPOSE: To test the potential of magnetic resonance imaging (MRI) in early detection of left ventricular (LV) dysfunction in patients with pulmonary regurgitation and normal LV ejection fraction after repair of tetralogy of Fallot. MATERIALS AND METHODS: Patients (n = 18) with repaired tetralogy of Fallot and pulmonary regurgitation were prospectively recruited. Healthy volunteers (n = 10) were used as control. Tagging MR images were acquired at the base, mid, and apical LV levels for assessing segmental rotation and circumferential strain. Cine MR images and velocity-encoded MR images were also acquired for assessment of biventricular volumes and biventricular function and pulmonary regurgitant fraction, respectively. Mean values were compared between groups using unpaired Student's t-test. RESULTS: Patients presented with preserved global LV function (LVEF of 59 ± 5%). A significant decrease in LV peak circumferential strain was seen in patients compared with normal volunteers at the basilar (-15.6 ± 4.5% vs. -17.6 ± 4.4%; P < 0.01) and apical (-14.4± 6.1% vs. -17.3± 5.1%, P < 0.01) slices. LV peak rotation was also delayed in patients compared with volunteers at the basilar (6.1 ± 2.6° vs. 4.2 ± 0.6°; P < 0.01) and mid (8.0 ± 1.7° vs. 4.9 ± 1.0°; P < 0.01) slices. CONCLUSION: MRI can detect early regional LV dysfunction in patients with preserved LVEF after repair of tetralogy of Fallot. MR may be a useful technique for guiding clinical decisions in these patients in order to prevent future global LV deterioration.

Tetralogy of Fallot: impact of the excursion of the interventricular septum on left ventricular systolic function and fibrosis after surgical repair.

PURPOSE: To quantify the excursion of interventricular septum (IVS) in patients after repair of tetralogy of Fallot (TOF), a marker of interventricular interaction, and assess its association with left ventricular (LV) ejection fraction, LV septal wall thickening, and LV fibrosis. MATERIALS AND METHODS: The HIPAA-compliant protocol received institutional board review approval. IVS excursion was measured at cardiovascular magnetic resonance (MR) imaging in 82 patients after repair of TOF and in 10 healthy volunteers. IVS excursion was correlated with LV ejection fraction, LV septal wall thickening, and LV delayed gadolinium enhancement. Independent predictors of reduced LV ejection fraction were identified, including significant univariable predictors with use of a multivariable logistic regression model. RESULTS: IVS excursion was greater in patients than in healthy volunteers (5.3 mm ± 3.1 vs 1.2 mm ± 0.4, P < .01). Patients (n = 68) with abnormal excursion of the IVS had reduced LV ejection fraction (57% ± 7 vs 61% ± 4, P < .01) and reduced LV septal wall thickening (24% ± 10 vs 29% ± 5, P = .01) compared with patients with normal IVS excursion. Maximal IVS excursion (odds ratio = 1.27 per millimeter, P = .03) and right ventricular (RV) ejection fraction (odds ratio = 0.92 per percentage, P = .031) were independent predictors of reduced LV ejection fraction (<55%). Among the 44 patients with delayed enhancement images, those with abnormal excursion of the IVS had higher LV delayed enhancement scores (median, 1.5 [interquartile range, 0-2] vs 0 [interquartile range, 0-0]; P < .01] than patients with normal IVS excursion. Notably, in all but one patient the delayed enhancement was located at the RV-LV hinge points. CONCLUSION: Abnormal IVS excursion after repair of TOF is associated with reduced global and septal LV systolic function and LV fibrosis at the RV-LV hinge points, suggesting a mechanism of adverse interventricular interaction.

Bicuspid aortic valve: four-dimensional MR evaluation of ascending aortic systolic flow patterns.

PURPOSE: To use time-resolved three-dimensional phase-contrast magnetic resonance (MR) imaging, also called four-dimensional flow MR imaging, to evaluate systolic blood flow patterns in the ascending aorta that may predispose patients with a bicuspid aortic valve (BAV) to aneurysm. MATERIALS AND METHODS: The HIPAA-compliant protocol received institutional review board approval, and informed consent was obtained. Four-dimensional flow MR imaging was used to assess blood flow in the thoracic aorta of 53 individuals: 20 patients with a BAV, 25 patients with a tricuspid aortic valve (TAV), and eight healthy volunteers. The Fisher exact test was used to evaluate the significance of flow pattern differences. RESULTS: Nested helical flow was seen at peak systole in the ascending aorta of 15 of 20 patients with a BAV but in none of the healthy volunteers or patients with a TAV. This flow pattern was seen both in patients with a BAV with a dilated ascending aorta (n = 6) and in those with a normal ascending aorta (n = 9), was seen in the absence of aortic stenosis (n = 5), and was associated with eccentric systolic flow jets in all cases. Fusion of right and left leaflets gave rise to right-handed helical flow and right-anterior flow jets (n = 11), whereas right and noncoronary fusion gave rise to left-handed helical flow with left-posterior flow jets (n = 4). CONCLUSION: Four-dimensional flow MR imaging showed abnormal helical systolic flow in the ascending aorta of patients with a BAV, including those without aneurysm or aortic stenosis. Identification and characterization of eccentric flow jets in these patients may help identify those at risk for development of ascending aortic aneurysm.

Clinical evaluation of aortic coarctation with 4D flow MR imaging.

PURPOSE: To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation. MATERIALS AND METHODS: Time-resolved, 3D phase contrast magnetic resonance imaging (MRI) (4D Flow) was used to assess blood flow in the thoracic aorta of 34 individuals: 26 patients with coarctation (22 after surgery or stent placement) and eight healthy volunteers. RESULTS: Direct comparison of blood flow calculated with 2D and 4D phase contrast data at standard levels for analysis in coarctation patients showed good correlation and agreement (correlation coefficient r = 0.99, limits of agreement = -20% to 20% for collateral blood flow calculations). Abnormal blood flow patterns were demonstrated at peak systole with 4D Flow visualization techniques in the descending thoracic aorta of patients but not volunteers. Marked helical flow was seen in 9 of 13 patients with angulated aortic arch geometries after coarctation repair. Vortical flow was seen in regions of poststenotic dilation. CONCLUSION: 4D Flow is a fast and reliable means of evaluating collateral blood flow in patients with aortic coarctation in order to establish hemodynamic significance. It also can detect distorted blood flow patterns in the descending aorta after coarctation repair.

Secondary repair of incompetent pulmonary valves after previous surgery or intervention: Patient selection and outcomes.

OBJECTIVES: Pulmonary valve (PV) regurgitation (PR) is common after intervention for a hypoplastic right ventricular outflow tract. Secondary PV repair is an alternative to replacement (PVR), but selection criteria are not established. We sought to elucidate preoperative variables associated with successful PV repair and to compare outcomes between repair and PVR. METHODS: Patients who underwent surgery for secondary PR from 2010 to 2017 by a single surgeon were studied. The PV annulus and leaflets were measured on the preoperative echocardiogram and magnetic resonance images, and the primary predictor variable was leaflet area indexed to ideal PV annulus area (iPLA) by magnetic resonance imaging. PV repair and PVR groups were compared using multivariable logistic regression, and with a conditional inference tree. Freedom from PV dysfunction and from reintervention were assessed with Kaplan-Meier survival analyses. RESULTS: Of 85 patients, 31 (36%) underwent PV repair. By multivariable analysis, longer PV total leaflet length (cm/m2) (ß = 3.00, standard error [SE] = 0.82, P < .001), larger PV z score (ß = 1.34, SE = 0.39, P = .001), and larger iPLA (ß = 8.13, SE = 2.62, P = .002) were associated with repair. iPLA of 0.90 or greater was 91% sensitive and 83% specific for achieving PV repair. At a median of 4.1 years follow-up, there was greater freedom from significant PR in the PV repair group (log rank P = .008). CONCLUSIONS: Patients with an iPLA >0.9, and those with an iPLA between 0.7 and 0.9 with a PV annulus z score >0 should be considered for a native PV repair. At midterm follow-up, patients with a PV repair were not more likely to develop PR or to require reintervention when compared with patients undergoing PVR.