Z-score Equations Research Articles

Abstract 165: Coronary Artery Dilatation in Kawasaki Disease is Associated with Anatomical Coronary Dominance: An Angiography-Based Study

Introduction: Coronary artery (CA) dilatation in Kawasaki disease (KD) is best determined by elevated Z-scores. Z-score equations, do not take into account anatomical CA dominance. We hypothesize that, except for CA aneurysms, CA dominance influences dilatation status in KD (Z-score > 2.5). Material and Methods: We retrospectively analyzed CA status in KD patients followed at our institution for persistent CA dilatation. All patients who had a diagnostic catheterization between 2002 and 2012 were considered. Serial echocardiographic dimensions of LCA, RCA, and LAD upon diagnosis, 1 week, 2 weeks, 4 weeks, 2 months, 3-6 months, and 9-12 months later were normalized to BSA using published CA Z-score equations. Data were contrasted with CA angiography description of CA dominance: right or left dominance was adopted when the respective CA supplies both diaphragmatic LV free wall and posterior inter ventricular septum (IVS); Co-dominance was when posterior IVS was supplied by RCA and diaphragmatic LV free wall by LCA. Results: Of 69 potential patients, 16 were excluded (9 never presented a CA dilatation and 7 had CA aneurysms). The interval between acute onset and selective CA angiography of the remaining 53 patients was 69.5±52.8months at 9.2±5.2years old. Of the latter, 20(37.7%) had LCA-dominance, 31(58.5%) RCA-dominance, and 2(3.8%) Co-dominance. Upon KD onset, the LCA-dominant subset had 14/20(70%) ipsilateral dilatation vs. 6/20(30%) contralateral dilatation. Similarly, RCA-dominant dilatation was ipsilateral in 21/31(68%) vs. 10/31(32%) contralateral dilatation (p=0.89). On late follow-up, persistent CA dilatation was similar between LCA-dominance 6/14(43%) and RCA-dominance 10/21(47%) (p=0.94). The interval between onset and normalizing CA Z-score was 1.16±1.65 vs. 2.45±3.6years in ispilateral vs. contralateral subsets (p=0.19). From the inflammatory perspective, serum albumin was significantly lower in patients with contralateral CA dilatation (p=0.02). Nevertheless, other inflammatory markers did not show a significant difference. Conclusion: Transitory CA dilatation following KD is closely related to anatomical dominance. This may be a reflection of vasodilation during immune carditis rather than coronary vasculitis.

Abstract O.53: Occult Coronary Artery Dilatation: An Unrecognized Category Of Coronary Involvement

Background: The current definition of Coronary artery dilatation (CAD), Z-score >2.5, in KD may omit patients at higher risk of later complications. We propose a category of occult CAD with a Z-score variation ≥ 2 for the same CA on 2 different echocardiograms, but absolute Z-score < 2.5. We compared this new category with cases of CAD and normal CA. >Method: A retrospective review included 337 patients diagnosed with KD in our institution. Echographic data were retrieved for the fist year following diagnosis. Patients were classified in three categories: definite CA dilatation (dCAD) with Z-score ≥ 2.5, occult CA dilatation (oCAD) and normal CA (nCA). We compared inflammatory profile, IVIG treatment resistance, and timing of CA involvement. Results: There were 26.3% patients with nCA, 32.2% with oCAD and 41.1% with dCAD.Patients with KD incomplete diagnostic criteria represented 35%, 14% and 17% for NCAD, OCAD and DCAD groups respectively (p=0.008). Median time for CAD was 7 and 9.5 days for dCAD and oCAD respectively (p=0.2). A Jonckheere trend test identified a progression of inflammatory parameters through the three groups for Platelet count (p< 0.001), Albumin (p = 0.007), ESR (p = 0.04), but not for CRP (p = 0.76) and WBC (p = 0.16). There was a significant difference in treatment resistance, with 5%, 19% and 31% for NCAD, OCAD and DCAD respectively (p=0,002). Conclusion: OCAD group appears like a distinctive subgroup of KD patients showing intermediate inflammatory profiles and treatment respond in the NCAD to DCAD spectrum. Recent Z-score equations, more accurate for young patients’ CA size than former linear equations, may explain the high incidence of dCAD in this report. Further studies are needed to define the profile and propensity to complications of this subpopulation.

Effect of Dual-Chamber Pacemaker Implantation on Aortic Dilatation in Patients With Congenital Heart Block

Ascending aortic dilatation (AoD) in patients with structurally normal hearts and congenital heart block (CHB) has been previously described. The cause and management of AoD are yet to be determined. The aim of this study was to test the hypothesis that AoD in children with CHB regresses after the implantation of cardiac dual-chamber pacemakers (PMs). The secondary hypothesis was an association between the presence of maternal antibodies (SS-A or SS-B) and the degree of aortic dilatation. Clinical data with echocardiographic correlates of patients with CHB followed at a single institution were retrospectively reviewed. Comparison of the target structures diameter was based on 3 different z-score equations, with AoD defined as a z score >2. Inclusion criteria were CHB diagnosis by 12-lead electrocardiography or Holter recording and benefit from a permanent dual-chamber PM. Excluded were patients with incomplete echocardiographic measurements, those with major structural heart defects, and those with syndromes or diseases known to be associated with AoD. There were 17 patients, diagnosed at a median age of 6 months (interquartile range 0 to 47.8). Maternal antibodies were positive in 6 patients and negative in 11. All patients underwent PM implantation at a median age of 4.5 years (interquartile range 1.4 to 7.9). AoD (z score >2.0 according to 3 different equations) was present in 35% to 59% of patients. There was a significant reduction of mean ascending aortic z score in patients with AoD from 4.66 to 3.67 (p = 0.06), from 4.82 to 2.95 (p = 0.002), and from 6.07 to 3.39 (p = 0.006) according to the various z-score equations. Most patients with positive serology had AoD, without reaching statistical significance. In conclusion, AoD is associated with CHB, more likely in infants exposed to maternal antibodies. AoD decreases after the implantation of a PM. This is probably related to the regularization of stroke volume.

Prenatal detection of coarctation of the aorta in a non-selected population: A prospective analysis of 10 years of experience

The aim of our prospective study was to assess the ability of different parameters to identify fetuses requiring neonatal care for coarctation of the aorta (CoA). Between January 2003 and December 2012, 175 fetuses of our region referred for great vessel disproportion (pulmonary valve/aortic valve (AoV) diameter ratio ≥ 1.6) were divided into two groups: group A ( n = 51) with high risk of CoA and delivery planned in tertiary care referral center; group B ( n = 124) with no increased risk of CoA. Fetuses with Z-score aortic valve AoV < −2 at 36 weeks of amenorrhea (WA) (measurements of AoV were normalized to femoral length with Schneider's Z-score equation) or with hypoplastic and/or angular aortic arches were considered at high risk of CoA and therefore in group A. Fetuses with at least 2 minor criteria: diagnosis before 28 WA, Z-score AoV < −1.2, ventricular septal defect and bicuspid AoV were also included in group A. Persistent left superior vena cava (LSVC) was not considered high risk, but was reported. All neonates in the 2 groups had completed postnatal follow-up with echocardiography. In group A, diagnosis of CoA was confirmed in 38/51 (75%) and isolated CoA in 22/34 (65%). In group B, 2/124 had CoA (false negative rate 1.6%). In univariate analysis, except for the LSVC, all parameters were significant ( P < 0.001) but had, if isolated, poor specificity. With our criteria, the positive predictive value was 75% when vessels disproportion was noted before 28 WA and 78% in the third trimester. 51% of all CoA had not been referred and was diagnosed after birth. The results of our prospective study are in agreement with those of previous series but our false positive rate is lower and not influenced by gestational age. The performance of fetal cardiac screening does not seem to be very good but prenatal diagnosis is probably not always possible: our 2 false negative cases had vascular disproportion without any other risk factors.

Could all coarctation of the aorta be identified at prenatal ultrasound?

Screening for coarctation of the aorta (CoA) during fetal ultrasound (US) in a low-risk population is based on the great vessels asymmetry (GVA) with small aorta. Over the last ten years, our screening rate was 49%. Some of the undetected CoA, that we had in care, seemed to us, to the view of the postnatal US, identifiable during pregnancy. We sought to assess the possible performance of fetal cardiac screening of CoA in an unselected population by the evaluation of aortic valve size measurement. We retrospectively analysed data from 199 neonates born after 32 weeks of gestation between January 2003 and December 2012: 77 were diagnosed for CoA among them 38 were prenatally considered at risk, 122 were referred in utero due to GVA to evaluate during pregnancy the risk of CoA after birth, but did not developed CoA. We compared them to a control group of 166 patients without significant congenital heart disease. US aortic annulus valve (AVA) sizes were measured (as we did prenatally) in parasternal long axis view between hinge points during systole and normalized to body size with Pettersen's Z-score equation. Mean AVA Z-scores were −0,05 in the controls, −1 in the GVA and −2,4 in the CoA group. AVA Z-scores were significantly smaller in the CoA group than in the control ( P < 0.05) and in the GVA group ( P < 0.05). The best cut-off point for Coa discrimination with ROC analysis was a Z-score of −1,84. Among the 39/77 CoA not identified prenatally, 19 had a Z-score < −2 and should probably have been identified. Five had a Z-score > −0,05 and could not be diagnosed. This study confirms that aortic annulus of newborns with CoA are significantly smaller than those with normal or even asymmetric in late pregnancy hearts. Although, on that basis alone, it is not possible to identify before birth all newborns who will develop CoA, as at least 6.5% presented CoA despite a normal AVA Z-score.

Reference Values for Echocardiographic Assessment of the Diameter of the Aortic Root and Ascending Aorta Spanning All Age Categories

Thoracic aortic dilatation requires accurate and timely detection to prevent progression to thoracic aortic aneurysm and aortic dissection. The detection of thoracic aortic dilatation necessitates the availability of cut-off values for normal aortic diameters. Tools to evaluate aortic dimension above the root are scarce and inconsistent regarding age groups. The aim of this study was to provide reference values for aortic root and ascending aortic diameters on the basis of transthoracic echocardiographic measurements in a large cohort of children and adults. Diameters at the level of the sinuses of Valsalva (SoV) and ascending aorta (AA) were assessed with transthoracic echocardiography in 849 subjects (453 females, age range 1 to 85 years, mean 40.1 ± 21.3 years) and measured according to published guidelines. Linear regression analysis was applied to create nomograms, as well as equations for upper limits of normal and z-scores. SoV and AA diameters were strongly correlated with age, body surface area (BSA), and weight (r = 0.67 to 0.79, p <0.001 for all). Male subjects had significantly larger aortic dimensions at all levels in adulthood, even after BSA correction (p ≤0.004 for all age intervals). Gender-, age-, and BSA-specific upper limits of normal and z-score equations were developed from a multivariate regression model, which strongly predicts SoV and AA diameters (adjusted R(2) for SoV = 0.84 and 0.67 and for AA = 0.82 and 0.74, for male and female subjects, respectively). In conclusion, this study provides widely applicable reference values for thoracic aortic dilatation screening purposes. Age, BSA, and gender must be taken into account when assessing an individual patient.

Comparability of Z-Score Equations of Cardiac Structures in Hypoplastic Left Heart Complex

Hypoplastic left heart complex (HLHC) is characterized by a mitral valve or an aortic valve annular Z score < -2, antegrade flow in the ascending aorta, ductal dependency, coarctation or aortic arch hypoplasia, and absence of significant (sub)valvar stenosis. The Z scores of the mitral and aortic valve annuli are major determinants of HLHC. Therefore, the algorithm for Z-score calculation is essential for diagnosis. However, no single universal method of calculation is in use. In the scientific literature addressing HLHC, various Z-score calculation methods have been applied. The aim of this study was to evaluate Z scores derived from two-dimensional echocardiographic dimensions in patients with HLHC. To compare the different published methods using two-dimensional echocardiographic measures for Z-score calculation, a cohort of 18 newborns diagnosed with HLHC was retrospectively evaluated. In addition, the methods to determine body surface area in newborns were evaluated. Three Z-score calculation methods were included and compared. Using the method of Daubeney et al. to calculate Z scores in our cohort illustrated a lack of correlation beyond a Z score < 0, compared with the methods of Zilberman et al. and Pettersen et al. Z scores calculated using Zilberman et al.'s and Pettersen et al.'s methods were fairly consistent. The equations used by Pettersen et al. are based on the largest population of neonates. Although the different methods for calculating Z scores for mitral and aortic valve dimensions correspond fairly well in the normal range, Z scores < -2 diverge substantially. A useful scientific comparison of published data and outcomes of patients with HLHC remains elusive. The Z-score calculation algorithms used by Pettersen et al. appear to be the most appropriate for use in an evaluation of HLHC. Because these different methods can yield different values, reporting the method as well as the Z score is essential for an accurate diagnosis. Similarly, the method used to determine body surface area should be reported.

A clinical appraisal of different Z-score equations for aortic root assessment in the diagnostic evaluation of Marfan syndrome

A clinical appraisal of different Z-score equations for aortic root assessment in the diagnostic evaluation of Marfan syndrome

Reference Ranges of Ductus Arteriosus Derived by Cardio-Spatiotemporal Image Correlation from 14 to 40 Weeks of Gestation

Objective: To construct reference ranges of fetal ductus arteriosus (DA) derived by volume datasets of cardio-spatiotemporal image correlation (cardio-STIC). Methods: Cardio-STIC volume datasets were acquired from low-risk singleton pregnancies with a reliable gestational age from 14 to 40 weeks. In offline analysis with 4D View version 9, fetal DA was measured in the transverse ductal arch view with orthogonal control in the multiplanar view. The reference ranges of the DA and Z-score equation were constructed against gestational weeks and biparietal diameter (BPD) as independent variables. Results: A total of satisfactory 606 volumes were analyzed. The reference ranges for predicting means and SDs of fetal DA were constructed based on the best-fit regression model. Mean DA (mm) was best predicted by linear model as a function of GA (weeks) and BPD (cm) as follows: Predicted DA diameter (cm) = -0.051 + 0.014 × GA (weeks) (r = 0.84) and Predicted DA diameter (cm) = -0.015 + 0.053 × BPD (cm) (r = 0.83). Models for Z-score calculation and centile charts for predicting fetal DA were also provided. Conclusion: Reference ranges of the fetal DA and Z-score model are provided. These may serve as a useful tool in the assessment of fetal DA, especially in fetal cardiac anomalies or in monitoring fetuses exposed to maternal indomethacin.

A clinical appraisal of different Z-score equations for aortic root assessment in the diagnostic evaluation of Marfan syndrome

Aortic sinus diameter dilatation expressed as a Z-score >2.0 is diagnostic in Marfan syndrome. In addition to the classic equation (Z1) for calculating Z-scores, two new equations were recently introduced (Z2 and Z3). We studied the effects of obesity, age, and the absolute cut point of 40 mm on these three equations in 2,674 echocardiographic measurements of 260 patients with Marfan syndrome. Diameters ≥40 mm were associated with Z1 scores <2.0 in 109 measurements (11.0%; 35 patients), Z2 scores <2.0 in 37 measurements (3.8%; 13 patients), and Z3 scores <2.0 in 24 measurements (2.4%; 11 patients). Mean diameters increased after the 40th birthday: 42.0 (37.3-44.8 mm interquartile range) to 42.5 (39.0-45.0 mm interquartile range; P = not significant) and mean Z1 scores decreased from 3.60 to 2.17 (P < 0.01), whereas Z2 and Z3 scores tended to increase (Z2: 3.04-3.27; Z3: 3.39-3.55; P = not significant for both). Comparing Z-scores between patients with body mass index <25 kg/m² (group A) and those with body mass index ≥25 kg/m² (group B), median Z1 scores differed between groups (Z1 = 3.00 in group A, Z1 = 1.78 in group B; P = 0.012), whereas Z2 (Z2 = 2.82 in group A, Z2 = 2.47 in group B; P = 0.52) and Z3 scores (Z3 = 2.72 in group A, Z2 = 3.12 in group B; P = 0.32) did not. Z1 scores are inferior to Z2 and Z3 scores in Marfan syndrome. In particular, the Z3 score, correcting aortic sinus diameter for body height, seems excellent.

1141 The Diameter of Coronary Arteries in Healthy Newborns at Birth, One and Six Months of Ages

ObjectiveThe aim of this study was to determine accurate and validated z-score equations for the normal values of coronary diameters adjusted with growth changes of the neonates by testing three...

The diameter of coronary arteries in healthy newborns at birth, 1 and 6 months of ages

Objective: The aim of this study was to determine accurate and validated Z-score equations for the normal values of coronary diameters adjusted with growth changes of the neonates by testing three different time periods. Methods: Echocardiography was performed on 200 healthy neonates at birth, 1 and 6 months of ages. Several regression models for the left (LCA) and right coronary artery (RCA) diameters were tested with weight, height, body surface area and aortic annulus diameter. Reliable standards for the coronary artery diameters for healthy newborns by determining Z-score equations with appropriate statistical validations were established. Results: The coronary diameters on birth measurements were strongly correlated with birth weight, height, surface area and the diameter of the aortic annulus (Pearson’s R > 0.8, all p < 0.01). There were significant associations between the mean data of weight, height, body surface area, aortic annulus and the LCA and RCA diameters measurements of study subjects at birth, 1 and 6 months of ages (p < 0.05). Z-score graphs of coronary artery diameters and weight of the subjects at three different time (LCA vs. weight at birth, R = 0.82, p < 0.001; LCA vs. weight at 1 month, R = 0.64, p < 0.001; LCA vs. weight at 6 months, R = 0.55, p < 0.001; RCA vs. weight at birth, R = 0.80, p < 0.001; RCA vs. weight at 1 month, R = 0.59, p < 0.001; RCA vs. weight at 6 months, R = 0.49, p < 0.001) were constructed. Conclusion: We present a new set of equations for neonatal Z-score calculation on the basis of a large number of healthy neonates on three different time period consisting of birth, 1 and 6 months of ages. It is clear with this study that the growth in caliber of the coronary arteries is definite and progressive during postnatal time.