J Appl Physiol 118: 1200–1206, 2015. First published April 2, 2015; doi:10.1152/japplphysiol.00533.2014.

Right ventricular dysfunction in children and adolescents conceived by assisted reproductive technologies Robert von Arx,1 Yves Allemann,1 Claudio Sartori,2 Emrush Rexhaj,1 David Cerny,1 Stefano F. de Marchi,1 Rodrigo Soria,1 Marc Germond,3 Urs Scherrer,1,4* and Stefano F. Rimoldi1* 1

Department of Cardiology and Clinical Research, University Hospital, Bern, Switzerland; 2Department of Internal Medicine, University Hospital, Lausanne, Switzerland; 3Centre de Procréation Médicalement Assistée, Lausanne, Switzerland; 4Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Arica, Chile

Submitted 19 June 2014; accepted in final form 26 March 2015

von Arx R, Allemann Y, Sartori C, Rexhaj E, Cerny D, de Marchi SF, Soria R, Germond M, Scherrer U, Rimoldi SF. Right ventricular dysfunction in children and adolescents conceived by assisted reproductive technologies. J Appl Physiol 118: 1200 –1206, 2015. First published April 2, 2015; doi:10.1152/japplphysiol.00533.2014.—Assisted reproductive technologies (ART) predispose the offspring to vascular dysfunction, arterial hypertension, and hypoxic pulmonary hypertension. Recently, cardiac remodeling and dysfunction during fetal and early postnatal life have been reported in offspring of ART, but it is not known whether these cardiac alterations persist later in life and whether confounding factors contribute to this problem. We, therefore, assessed cardiac function and pulmonary artery pressure by echocardiography in 54 healthy children conceived by ART (mean age 11.5 ⫾ 2.4 yr) and 54 age-matched (12.2 ⫾ 2.3 yr) and sexmatched control children. Because ART is often associated with low birth weight and prematurity, two potential confounders associated with cardiac dysfunction, only singletons born with normal birth weight at term were studied. Moreover, because cardiac remodeling in infants conceived by ART was observed in utero, a situation associated with increased right heart load, we also assessed cardiac function during high-altitude exposure, a condition associated with hypoxic pulmonary hypertension-induced right ventricular overload. We found that, while at low altitude cardiac morphometry and function was not different between children conceived by ART and control children, under the stressful conditions of high-altitude-induced pressure overload and hypoxia, larger right ventricular end-diastolic area and diastolic dysfunction (evidenced by lower E-wave tissue Doppler velocity and A-wave tissue Doppler velocity of the lateral tricuspid annulus) were detectable in children and adolescents conceived by ART. In conclusion, right ventricular dysfunction persists in children and adolescents conceived by ART. These cardiac alterations appear to be related to ART per se rather than to low birth weight or prematurity. fetal programming; cardiac function; assisted reproductive technologies; in vitro fertilization IN ANIMALS AND HUMANS adverse events during early life cause alterations of cardiovascular function (12, 34, 40) that are associated with increased cardiovascular risk later in life (5), and the term fetal programming of cardiovascular disease has been coined to describe this problem. Assisted reproductive technologies (ART) represent an important example of fetal programming (37), as evidenced by systemic and pulmonary vascular dysfunction (42) and arterial hypertension (7) in children conceived by ART and premature vascular aging,

* U. Scherrer and S. Rimoldi contributed equally to this work. Address for reprint requests and other correspondence: S. Rimoldi, Dept. of Cardiology and Clinical Research, Univ. Hospital, CH-3010 Bern, Switzerland (e-mail: [email protected]). 1200

arterial hypertension, and shortened life span in ART mice (35). Very recently, cardiac remodeling in utero that persists into early postnatal life has been demonstrated in children conceived by ART (43). However, it is not known how this cardiac dysfunction evolves and whether confounding factors contribute to this problem. We speculated that, in children conceived by ART, right ventricular (RV) dysfunction persists and is related to ART per se, rather than to prematurity or low birth weight. To test this hypothesis, we assessed cardiac function in healthy children and adolescents conceived by ART and age- and sex-matched control children. Because ART is associated with an increased prevalence of prematurity and low birth weight (10), two possible confounders known to be associated with cardiac remodeling and dysfunction (8, 20, 21), we studied only singletons born at term with normal birth weight. Moreover, because cardiac remodeling in children conceived by ART was observed in utero, a situation associated with increased right heart load, we also assessed cardiac function during highaltitude exposure, a condition associated with hypoxic pulmonary hypertension-induced RV overload (3, 4). MATERIALS AND METHODS

Study subjects and protocol. We studied 54 healthy children and adolescents conceived by ART (mean age 11.5 ⫾ 2.4 yr; range 7-18 yr) and 54 age-matched (mean age 12.2 ⫾ 2.3 yr; range 7–17 yr) and sex-matched controls (Table 1). ART participants were selected by one of us (M. Germond), who performed all the procedures. Inclusion criteria were as follows: singleton, born at term (⬎37 wk gestational age) with normal birth weight (⬎2,500 g), at the end of a normal pregnancy without any complications during the perinatal period. Exclusion criteria included any acute disease or medical treatment and high-altitude (i.e., ⬎2,500 m) exposure during the 3 mo preceding the study. All parents provided written informed consent. The study was approved by the institutional review boards on human investigation of the Universities of Bern and Lausanne and was registered (Clinical Trials Gov Registration no. NCT00837642). Children conceived by ART fulfilling the inclusion criteria were contacted by letter, and those agreeing to participate were included in the study. Control children were recruited by the families of the children conceived by ART to ensure comparable socioeconomic background. None of the children suffered from congenital heart disease. Among the children conceived by ART, 24 were conceived by in vitro fertilization and 30 by intracytoplasmic sperm injection. The echocardiographic examination at low altitude was performed at the University Hospital in Bern, Switzerland (550 m). Representative (age, 11.3 ⫾ 2.5 vs. 10.8 ⫾ 2.1 yr, P ⫽ 0.40, ART vs. control; body surface area, 1.4 ⫾ 0.3 vs. 1.3 ⫾ 0.2 m2; P ⫽ 0.22, ART vs. control) subgroups (n ⫽ 30 each) of children conceived by ART and

8750-7587/15 Copyright © 2015 the American Physiological Society

http://www.jappl.org

Cardiac Function and Assisted Reproductive Technology

Table 1. Participants characteristics

Variable

Female/male, n Gestational age, wk Birth weight, g Birth length, cm Age, yr Height, cm Weight, kg Body mass index, kg/m2 Body surface area, m2 Heart rate, beats/min Systolic BP, mmHg Diastolic BP, mmHg Maternal age, yr Maternal smoking status, n (%) Presence of other cardiovascular risk factor in the mother, n (%)

Control Children (n ⫽ 54)

Children Conceived by ART (n ⫽ 54)

P Value

27/27 39.2 ⫾ 1.9 3379 ⫾ 403 49.7 ⫾ 1.7 12.2 ⫾ 2.3 152 ⫾ 14 45.3 ⫾ 15.3 18.9 ⫾ 3.0 1.4 ⫾ 0.3 71 ⫾ 9 113 ⫾ 10 70 ⫾ 7 29.8 ⫾ 4.7 9 (18%)

27/27 39.3 ⫾ 2.0 3273 ⫾ 557 49.7 ⫾ 2.1 11.5 ⫾ 2.4 150 ⫾ 15 41.6 ⫾ 12.6 18.1 ⫾ 2.7 1.3 ⫾ 0.3 71 ⫾ 10 113 ⫾ 9 69 ⫾ 7 32.7 ⫾ 3.9 6 (12%)

— 0.74 0.29 0.93 0.17 0.38 0.20 0.21 0.26 0.90 0.95 0.58 0.001 0.58

1 (2%)

1 (2%)

1.0

Data are expressed as means ⫾ SD. Presence of other cardiovascular risk factors in the mothers includes the presence of at least 1 of the following: arterial hypertension, diabetes mellitus, or dyslipidemia. ART, assisted reproductive technologies; BP, blood pressure.

control children were also studied at high altitude. The children ascended by a 2.5-h train ride to the high-altitude research station Jungfraujoch, Switzerland at 3,454 m and spent 2 days and 2 nights at this laboratory. During the stay, all participants received the same diet, and care was taken to assure adequate fluid intake. Measurements were performed on the morning before descent (i.e., ⬃40 h after arrival at the high-altitude research station). Echocardiographic exam. Echocardiographic recordings were obtained in the left lateral position using an Acuson Sequoia 512 ultrasound system (Acuson, Mountain View, CA), equipped with a 4V1c adult and a 7V3c pediatric transducer with an integrated color Doppler system (3.6 or 6.0 MHz for pulsed and 2.15 or 3.6 MHz for continuous-wave Doppler recording). Tricuspid regurgitation (continuous-wave Doppler), RV two-dimensional clips, and tricuspid annular motion (pulsed-wave tissue Doppler) were acquired from an apical four-chamber view. Data were stored on DVD or MO disc and



von Arx R et al.

1201

analyzed offline by two investigators (R. von Arx, S. Rimoldi), who were unaware of the subject identity and study site. Reported values represent the mean of at least three measurements. RV systolic and diastolic function. RV systolic and diastolic function was assessed according to the guidelines (18, 22, 39) and as previously described (4, 31). Briefly, end-systolic and -diastolic RV areas were manually traced from a two-dimensional echocardiographic clip (Fig. 1), and the RV fractional area change was calculated (18). Indexed (for body surface area) RV end-diastolic area assessed by 2D echocardiography correlates with MRI-derived RV end-diastolic volume (1). Tricuspid annular peak systolic excursion (TAPSE) was assessed by M-mode from the apical four-chamber view. TAPSE reflects the longitudinal systolic excursion of the lateral RV wall, which is closely related to RV ejection fraction and has a good predictive value in detecting patients at risk for right heart failure (16). The intraobserver (R. von Arx) coefficient of variation for RV area measurements (n ⫽ 20) was 4.3%, and the interobserver coefficient of variation (R. von Arx, S. Rimoldi) was 5.9% at low altitude and respectively 4.8 and 6.2% at high altitude. The peak systolic velocity of the lateral tricuspid annulus (Tricuspid S=) was assessed using pulse-wave tissue Doppler tracings. Tricuspid S= has a good sensitivity and specificity in predicting systolic RV dysfunction (30). We also assessed tricuspid annular isovolumic acceleration, a proxy of RV contractility (44) that has been shown to be relatively load independent and useful for the assessment of RV function in children (9). Regional RV strain rate (and time to strain rate peak), a measure of regional contractility with low heart rate dependency (11, 45), was assessed using speckle tracking technology (Syngo Workplace v. 3.1; Siemens Medical Solutions, Mountain View, CA), as previously described (4). Measurements were limited to the middle portion of the RV free wall, because this portion is particularly prone to pulmonary hypertension-induced dysfunction (14, 23). RV diastolic function was assessed by measuring the early (E=) and late (A=) diastolic velocities of the lateral tricuspid annulus, using the pulse-wave tissue Doppler tracings, as previously described (4, 31). Left ventricular structure, function, and cardiac output. Left ventricular mass index was calculated according to the cube formula, using end-diastolic values of septal and posterior wall thickness and left ventricular cavity dimension, and divided by body surface area, as previously described (2).

Fig. 1. End-diastolic right ventricular (RV) planimetry in a participant studied at low (left, 13.6 cm2) and at high altitude (right, 10.3 cm2).

J Appl Physiol • doi:10.1152/japplphysiol.00533.2014 • www.jappl.org

1202

Cardiac Function and Assisted Reproductive Technology

To assess systolic left ventricular function, left ventricular ejection fraction was calculated using the modified biplane Simpson methods. Left ventricular diastolic function was assessed from the apical fourchamber view using transmitral Doppler flow velocity and mitral annular motion velocity measurements, as previously described (2, 4). Cardiac output was determined by measuring the diameter of the left ventricular outflow tract and the time-velocity integral of its Doppler signal. The left ventricular outflow tract diameter was measured in the parasternal long-axis view, and its surface was calculated assuming circular geometry. The stroke volume was calculated by multiplying the left ventricular outflow tract time velocity integral with the cross-sectional area. Cardiac output was then obtained by multiplying stroke volume with heart rate. We previously reported an intra- and interobserver variability of 10.7 ⫾ 10.2% and 7.2 ⫾ 4.0%, respectively, for cardiac output measurements in children at high altitude (12). Cardiac index was obtained by dividing cardiac output by body surface area (m2). Left and right atrial area. Left (LA) and right atrial (RA) areas were assessed by planimetry in a four-chamber view at end-systole just before the mitral and the tricuspid valve opens (22). Pulmonary artery pressure. To estimate systolic pulmonary artery pressure, we measured the peak systolic transtricuspidal jet velocity in all possible views and calculated the RV to RA pressure gradient (RV-RA gradient) using the highest jet velocity of the qualitatively best signal, as previously described (3, 4, 12, 42). Noninvasive estimation of pulmonary artery pressure and has been validated against invasive measurements at high altitude (3). In 30 children at high altitude, the intra- and interobserver variability for these pressure gradient measurements was 5.1 ⫾ 4.6% and 6.0 ⫾ 8.6%, respectively (12). Arterial oxygen saturation. Transcutaneous arterial oxygen saturation was measured at a fingertip with a pulse oxymeter (OxiMax N-65; Nellcor, Pleasanton, CA). Statistical analysis. Statistical analysis was performed using the GraphPad Prism 5 software package (GraphPad Software, San Diego, CA). The unpaired two-sided Student’s t-test was used for comparisons of continuous variables between children conceived by ART and controls. Statistical analysis of end-diastolic RV area, RV diastolic function, and pulmonary artery pressure of the subgroup of children (n ⫽ 30 controls and n ⫽ 30 ART) exposed to low and high altitude was performed using a repeated-measures ANOVA (RMANOVA), with altitude and group as the factors. Post hoc testing of high-altitude values within the RMANOVA was done using the Bonferroni adjustment. For comparisons of categorical variables between children conceived by ART and control children, we used the Fischer exact test. Normal distribution of continuous variables was assessed with the D’Agostino and Pearson omnibus normality test. Relations between variables were analyzed by calculating the Pearson productmoment correlation coefficients. Power calculation based on previously reported systolic RV function data in healthy children (4) and children born after fetal growth restriction (8), assuming that a 1.5 cm/s difference in systolic tricuspid annular peak velocity (S=) is relevant (SD of S= 2.0 cm/s, power ⬎ 0.80; ␣ ⫽ 0.05), revealed that 29 subjects per group were needed to address this aim. A P value ⬍0.05 was considered statistically significant. Results are expressed as means ⫾ SD. RESULTS

Participant characteristics. Gestational age and birth weight were similar and normal in the two groups (Table 1). Age, height, weight, and body surface area as well as heart rate and systemic blood pressure were similar in children conceived by ART and control children. All continuous variables were normally distributed. Maternal smoking status and cardiovascular risk profile were comparable in the two groups.



von Arx R et al.

Cardiac morphometry, function, and pulmonary artery pressure at low altitude. Left ventricular mass index and LA area were normal and comparable in children conceived by ART and control children (Table 2). Systolic and diastolic left ventricular function was normal (28) and comparable in the two groups. Similarly, RV end-diastolic and systolic area and RA area were normal and comparable between the two groups (Fig. 2A). Systolic and diastolic RV function (Fig. 2, B and C) parameters were also comparable in children conceived by ART and control children and within reported reference values for this age group (15, 16). Pulmonary artery pressure was within normal limits (⬍24 mmHg) in all participants (25) (Fig. 2D). Cardiac morphometry, function, and pulmonary artery pressure at high altitude. Systolic and diastolic left ventricular function was comparable in ART and control children and similar to previously reported data in healthy children at this study altitude (Table 3) (4). Systolic RV function was similar in children conceived by ART and control children. RV enddiastolic area was significantly larger in children conceived by ART than in control children (Fig. 2A), and E= (Fig. 2B) and A= (Fig. 2C) diastolic velocities of the lateral tricuspid annulus were significantly lower in children conceived by ART than controls. As expected (42), pulmonary artery pressure estiTable 2. LV and RV structure and function in control children and children conceived by ART at low (550 m) altitude Variable

Left heart structure and function LVEF (biplane), % LV Mass index, g/m2 Cardiac index, l/m2 per min Left atrium area, cm2 Transmitral E wave, cm/s Transmitral A wave, cm/s Transmitral E/A ratio E-wave deceleration time, ms IVRT, ms E’ septal, cm/s A’ septal, cm/s E’/A’ ratio septal Right heart structure and function RV end-diastolic area, cm2 RV end-systolic area, cm2 FAC, % TAPSE, mm Tricuspid S’, cm/s IVA, m/s2 Strain rate, s⫺1 Time to strain rate peak, ms Right atrium area, cm2 E’ tricuspidal, cm/s A’ tricuspidal, cm/s E’/A’ ratio tricuspidal RV-RA gradient, mmHg

Controls (n ⫽ 54)

ART (n ⫽ 54)

P Value

64 ⫾ 4 66 ⫾ 12 2.72 ⫾ 0.57 9.9 ⫾ 3.4 90 ⫾ 11 44 ⫾ 9 2.1 ⫾ 0.4 145 ⫾ 15 75 ⫾ 8 14.0 ⫾ 2.7 7.2 ⫾ 1.4 2.0 ⫾ 0.4

64 ⫾ 3 66 ⫾ 10 2.68 ⫾ 0.49 9.4 ⫾ 3.9 88 ⫾ 13 43 ⫾ 10 2.1 ⫾ 0.5 146 ⫾ 14 74 ⫾ 9 13.5 ⫾ 2.4 7.0 ⫾ 1.3 2.0 ⫾ 0.4

0.81 0.95 0.65 0.40 0.61 0.54 0.81 0.39 0.38 0.37 0.38 0.95

18.6 ⫾ 4.8 10.3 ⫾ 3.1 45 ⫾ 7 20.2 ⫾ 1.7 14.6 ⫾ 2.1 2.60 ⫾ 0.85 2.01 ⫾ 0.41 203 ⫾ 35 8.6 ⫾ 2.5 16.6 ⫾ 2.5 8.9 ⫾ 1.6 1.9 ⫾ 0.4 17 ⫾ 3

19.0 ⫾ 4.0 10.9 ⫾ 2.7 44 ⫾ 6 20.1 ⫾ 2.0 14.4 ⫾ 2.2 2.70 ⫾ 0.63 2.08 ⫾ 0.42 203 ⫾ 47 8.5 ⫾ 3.3 16.8 ⫾ 2.8 8.8 ⫾ 1.5 1.9 ⫾ 0.3 16 ⫾ 2

0.72 0.30 0.34 0.95 0.64 0.50 0.41 0.93 0.75 0.78 0.62 0.75 0.21

Data are expressed as means ⫾ SD. LV, left ventricular; RV, right ventricular; LVEF, LV ejection fraction; A, late (transmitral) peak flow velocity; E, early (transmitral) peak flow velocity; E’, E-wave tissue Doppler velocity; A’, A-wave tissue Doppler velocity; IVRT, isovolumetric relaxation time; FAC, fractional area change; TAPSE, tricuspid annular peak systolic excursion; S’, systolic tricuspid annular peak velocity; IVA, isovolumic contraction acceleration; RA, right atrial.

J Appl Physiol • doi:10.1152/japplphysiol.00533.2014 • www.jappl.org

Cardiac Function and Assisted Reproductive Technology



von Arx R et al.

1203

Fig. 2. RV end-diastolic area (A), diastolic function (E= and A= velocities of the lateral tricuspid annulus, B and C, respectively) and pulmonary artery pressure (D) in control children (n ⫽ 30) and children conceived by assisted reproductive technologies (ART; n ⫽ 30) at low and high altitude. Data represent means ⫾ SE. P values represent high-altitude values within the repeatedmeasures ANOVA after Bonferroni adjustment. RA, right atrial.

mated by the RV-RA gradient was significantly higher in children conceived by ART than in control children (Fig. 2D). In the study population, there existed no relationship between pulmonary artery pressure and RV end-diastolic area (r ⫽ 0.08, Table 3. LV and RV structure and function in controls and children conceived by ART at high (3454 m) altitude Controls (n ⫽ 30)

ART (n ⫽ 30)

65 ⫾ 4 66 ⫾ 12 2.9 ⫾ 0.5 8.3 ⫾ 2.7 79 ⫾ 12 55 ⫾ 11 1.5 ⫾ 0.3 152 ⫾ 25 68 ⫾ 7 15.0 ⫾ 2.4 8.6 ⫾ 1.6 1.8 ⫾ 0.3

65 ⫾ 5 66 ⫾ 10 2.9 ⫾ 0.5 8.5 ⫾ 3.8 76 ⫾ 11 54 ⫾ 10 1.4 ⫾ 0.3 152 ⫾ 17 70 ⫾ 6 14.3 ⫾ 2.5 8.1 ⫾ 1.9 1.8 ⫾ 0.3

0.99 0.68 0.94 0.77 0.32 0.77 0.64 0.94 0.25 0.33 0.25 0.48

15.7 ⫾ 2.9 8.7 ⫾ 1.8 44 ⫾ 8 20.9 ⫾ 1.8 16.2 ⫾ 1.9 5.1 ⫾ 1.0 2.01 ⫾ 0.44 184 ⫾ 43 7.7 ⫾ 2.3 19.2 ⫾ 2.2 12.1 ⫾ 1.8 1.6 ⫾ 0.3 32 ⫾ 10

17.9 ⫾ 3.9 10.2 ⫾ 3.0 43 ⫾ 9 20.7 ⫾ 3.0 15.7 ⫾ 2.5 5.0 ⫾ 1.1 2.29 ⫾ 0.45 179 ⫾ 37 7.8 ⫾ 3.5 16.8 ⫾ 2.8 10.2 ⫾ 2.2 1.7 ⫾ 0.5 38 ⫾ 10

0.01 0.03 0.72 0.76 0.41 0.64 0.02 0.69 0.77 0.0015 0.002 0.67 0.03

Variable

Left heart structure and function LVEF (biplane), % LV Mass index, g/m2 Cardiac index, l/m2 per min Left atrium area, cm2 Transmitral E wave, cm/s Transmitral A wave, cm/s Transmitral E/A ratio E-wave deceleration time, ms IVRT, ms E’ septal, cm/s A’ septal, cm/s E’/A’ ratio septal Right heart structure and function RV end-diastolic area, cm2 RV end-systolic area, cm2 FAC, % TAPSE, mm Tricuspid S’, cm/s IVA, m/s2 Strain rate, s⫺1 Time to strain rate peak, ms Right atrium area, cm2 E’ tricuspidal, cm/s A’ tricuspidal, cm/s E’/A’ ratio tricuspidal RV-RA gradient, mmHg

Data are expressed as means ⫾ SD.

P Value

P ⫽ 0.58), E= tricuspid (r ⬍ 0.01, P ⫽ 0.95), or A= tricuspid (r ⬍ 0.01, P ⫽ 0.96), respectively. The respiratory change of the diameter of the inferior vena cava was comparable in children conceived by ART and control children (49 ⫾ 8 vs. 46 ⫾ 7% P ⫽ 0.20), suggesting a similar central venous pressure in the two groups. Arterial oxygen saturation (89.4 ⫾ 2.3 vs. 89.4 ⫾ 2.4%, P ⫽ 0.95), heart rate (97 ⫾ 14 vs. 97 ⫾ 11 beats/min, P ⫽ 0.9) and cardiac index (Table 3) were comparable in children conceived by ART and control children. DISCUSSION

ART makes up for an important (2 to 5%) part of births in industrialized countries (27), and there is increasing evidence that the vasculature and arterial blood pressure are altered in this population (35–37, 42). Very recently, cardiac remodeling and dysfunction during fetal and early postnatal life (43) have also been reported in offspring of ART, but there is no information on whether these problems persist later in life. Here, we found that, while at low altitude, cardiac morphometry and function was not different between children conceived by ART and control children, under the stressful condition of high-altitude-induced RV pressure overload and hypoxia, larger RV end-diastolic area and diastolic dysfunction were detectable in apparently healthy children and adolescents conceived by ART. These cardiac alterations were not related to low birth weight or prematurity that are often associated with ART and known to predispose children to cardiac dysfunction (10). Several recent studies have shown that fetal programming of cardiovascular disease is not limited to vascular dysfunction (12, 42) and arterial hypertension (19) but also involves the heart (8, 20, 21). For example, fetal growth restriction results in cardiac remodeling and less efficient hearts in children (8),

J Appl Physiol • doi:10.1152/japplphysiol.00533.2014 • www.jappl.org

1204

Cardiac Function and Assisted Reproductive Technology

and preterm birth is associated with RV and left ventricular systolic dysfunction in young adults (20, 21). The present findings indicate that ART represents a novel means by which fetal programming of cardiac dysfunction can take place. We found that, in people conceived by ART, RV dysfunction described in utero persists into adolescence and can be detected under the stressful conditions of high-altitude exposure. In children, adaptation of the pulmonary circulation to this altitude occurs within 30 to 40 h (17), suggesting that the observed cardiac alterations in children conceived by ART are sustained because they were detectable after adaptation to the ambient hypoxia. These cardiac alterations were not related to the presence of confounding pathological events during the fetal period. This is important because ART is associated with an increased prevalence of low birth weight and prematurity (10, 24, 46), and, in the earlier study describing cardiac alterations in utero and during the first months of life (43), it was impossible to rule out confounding effects of these pathological events in the pathogenesis of the observed cardiac dysfunction. Taken together, these observations are consistent with the hypothesis that ART per se induces cardiac dysfunction and that a second hit (i.e., prematurity, fetal growth restriction) is not necessary to induce this problem. In line with this concept, a second hit also is not needed for ART-induced vascular dysfunction and premature vascular ageing in animals and humans (35, 42). It remains possible, however, that a second hit may result in more severe ART-induced cardiac alterations. Further study is needed to test for this possibility. In infants conceived by ART, cardiac remodeling and dysfunction during fetal and early postnatal life were more pronounced in the RV than the left ventricle (43). This could be related to the increased RV workload during fetal life and/or the greater vulnerability to pressure overload of the RV (26). We, therefore, also assessed RV function during high-altitude exposure, a maneuver known to invariably increase pulmonary artery pressure in humans and induce RV dysfunction in susceptible subjects (38, 41). As expected, pulmonary artery pressure was significantly higher in children conceived by ART than in control children (41), a phenomenon attributed to pulmonary endothelial dysfunction related at least in part to exaggerated oxidative stress (36, 37). Most importantly, we found that, at high altitude, children conceived by ART showed RV dysfunction. These RV alterations in children conceived by ART do not appear to be related to the larger altitude-induced increase of pulmonary artery pressure because there existed no relationship between pulmonary artery pressure and RV morphometry and diastolic function. The underlying mechanism of ART-induced cardiac dysfunction is not clear. In mice, ART-induced premature vascular ageing and arterial hypertension are related to epigenetic alteration of the endothelial nitric oxide (NO) synthase gene resulting in impaired vascular NO synthesis and increased oxidative stress (35). In humans, increased oxidative stress appears also to play a pathogenic role in ART-induced pulmonary vascular dysfunction, as evidenced by normalization of oxidative stress, plasma NO, and pulmonary vascular function by antioxidant vitamins (36, 37). There is evidence that oxidative stress facilitates cardiac dysfunction in humans and experimental animal models (37). Further study is needed to determine whether altered redox regulation contributes to ART-induced



von Arx R et al.

cardiac dysfunction. Finally, RV systolic function in children conceived by ART was normal at high altitude, and the RV, by increasing its contractility, was able to maintain the stroke volume in the presence of an acute increase in afterload in all participants. In high-altitude dwellers with pulmonary vascular dysfunction and a modest increase of pulmonary artery pressure at rest, exercise induces markedly exaggerated pulmonary hypertension [particularly in the presence of a persistent foramen ovale (6)] and rapid interstitial fluid accumulation (32). It is tempting to speculate that, in people conceived by ART, a similar phenomenon may occur. Limitations. We used two-dimensional echocardiographic measurements of RV area as a proxy of RV volume and remodeling. Although 2D echocardiography may be less precise than MRI or 3D echocardiographic imaging to assess RV structure, these latter methods are difficult to use under field conditions at high altitude (MRI) or necessitate large transducers (3D echocardiography), making it difficult to penetrate the small intercostal space in children. Moreover, it should be noted that 2D echo imaging quality of the RV in children is much better than in adults and that the intra- and interobserver variability of the RV assessments in the present study were small. In line with these observations, data in children with pulmonary hypertension show that conventional 2D echo indices of RV function are a valid tool to assess the risk for death or lung transplant in children with pulmonary hypertension (13). Furthermore, data in children with repaired tetralogy of Fallot show a correlation (r ⫽ 0.60) between RV end-diastolic area (normalized by body surface area) measured by 2D echo and RV end-diastolic volume assessed by MRI (1). The difference of RV end-diastolic area at high altitude is related to the control group RV end-diastolic area getting smaller, whereas the RV area average in the ART group remained almost unchanged compared with the low-altitude values. The comparison of RV end-diastolic areas between low and high altitude is complicated by the fact that altitude invariably induces tachycardia. We have previously shown that, during high-altitude exposure of healthy children (4), RV end-diastolic area decreases compared with low altitude because of the relative tachycardia resulting in shorter diastolic filling time. In the present study, we found that at high altitude for a similar heart rate RV end-diastolic area was significantly larger in children conceived by ART than in control children. This observation suggests relative enlargement of the RV, particularly when taking into account the presence of RV diastolic dysfunction (evidenced by a lower E= and A= velocities) that should have counteracted the enlargement. Tissue Doppler measurements are dependent on the Doppler alignment, and the transducer position needs to be maintained parallel to the direction of maximal annular motion. Although data on diastolic function of the RV are limited in pediatric populations (9), a recent study in children with pulmonary hypertension (29) found a good correlation between echocardiographic estimation of diastolic RV function and invasive reference measurements. RV diastolic function is dependent on the viscoelastic properties of the RV (33) and pre- and afterload conditions. Because we did not analyze the histological or biochemical properties of the RV, we cannot exclude the possibility that differences of the viscoelastic properties of the RV contributed to diastolic dysfunction in children conceived by ART. Alter-

J Appl Physiol • doi:10.1152/japplphysiol.00533.2014 • www.jappl.org

Cardiac Function and Assisted Reproductive Technology

natively, loading conditions could also influence tissue Doppler measurements. It is unlikely that the increased afterload (higher pulmonary artery pressure) in children conceived by ART played an important role because there existed no relationship between pulmonary artery pressure and diastolic parameters of the RV. Similarly, preload was also comparable in children conceived by ART and control children. Taken together, these results suggest that RV dysfunction in children conceived by ART was not related to different loading conditions. Finally, we do not know whether the changes persist after full high-altitude adaptation and how differences in tissue Doppler measurements translate into exercise capacity because, for logistical reasons, we could not perform measurements after full high-altitude adaptation and assess exercise responses in our study. In conclusion, we show for the first time that RV dysfunction persists in apparently healthy children and adolescents conceived by ART. These cardiac alterations appear not to be related to confounding cardiac pathogenic events during pregnancy but to ART per se. ACKNOWLEDGMENTS We are indebted to the International Foundation High Altitude Research Stations Jungfraujoch and Gornergrat for providing the facilities at the Jungfraujoch, to the custodians for the support of our activities, and to Siemens for providing the echocardiographic equipment. GRANTS This work was supported by grants from the Swiss National Science Foundation and the Placide Nicod Foundation. DISCLOSURES No conflicts of interest, financial or otherwise, are declared by the authors. AUTHOR CONTRIBUTIONS Author contributions: R.V.A., Y.A., C.S., E.R., D.C., S.F.d.M., R.S., and S.F.R. performed experiments; R.V.A., Y.A., C.S., E.R., D.C., S.F.d.M., R.S., U.S., and S.F.R. analyzed data; R.V.A., Y.A., C.S., E.R., D.C., S.F.d.M., R.S., M.G., U.S., and S.F.R. interpreted results of experiments; R.V.A. and S.F.R. prepared figures; R.V.A., E.R., and D.C. drafted manuscript; R.V.A., Y.A., C.S., E.R., D.C., S.F.d.M., R.S., M.G., U.S., and S.F.R. approved final version of manuscript; Y.A., C.S., M.G., U.S., and S.F.R. conception and design of research; Y.A., C.S., S.F.d.M., R.S., M.G., U.S., and S.F.R. edited and revised manuscript. REFERENCES 1. Alghamdi MH, Grosse-Wortmann L, Ahmad N, Mertens L, Friedberg MK. Can simple echocardiographic measures reduce the number of cardiac magnetic resonance imaging studies to diagnose right ventricular enlargement in congenital heart disease? J Am Soc Echocardiogr 25: 518 –523, 2012. 2. Allemann Y, Rotter M, Hutter D, Lipp E, Sartori C, Scherrer U, Seiler C. Impact of acute hypoxic pulmonary hypertension on LV diastolic function in healthy mountaineers at high altitude. Am J Physiol Heart Circ Physiol 286: H856 –H862, 2004. 3. Allemann Y, Sartori C, Lepori M, Pierre S, Melot C, Naeije R, Scherrer U, Maggiorini M. Echocardiographic and invasive measurements of pulmonary artery pressure correlate closely at high altitude. Am J Physiol Heart Circ Physiol 279: H2013–H2016, 2000. 4. Allemann Y, Stuber T, de Marchi SF, Rexhaj E, Sartori C, Scherrer U, Rimoldi SF. Pulmonary artery pressure and cardiac function in children and adolescents after rapid ascent to 3,450 m. Am J Physiol Heart Circ Physiol 302: H2646 –H2653, 2012. 5. Barker DJ. The developmental origins of well-being. Philos Trans R Soc Lond B Biol Sci 359: 1359 –1366, 2004.



von Arx R et al.

1205

6. Brenner R, Pratali L, Rimoldi SF, Murillo Jauregui CX, Soria R, Rexhaj E, Salinas Salmon C, Villena M, Romero C, Sartori C, Allemann Y, Scherrer U. Exaggerated pulmonary hypertension and right ventricular dysfunction in high-altitude dwellers with patent foramen ovale. Chest 147: 1072–1079, 2015. 7. Ceelen M, van Weissenbruch MM, Vermeiden JP, van Leeuwen FE, Delemarre-van de Waal HA. Cardiometabolic differences in children born after in vitro fertilization: follow-up study. J Clin Endocrinol Metab 93: 1682–1688, 2008. 8. Crispi F, Bijnens B, Figueras F, Bartrons J, Eixarch E, Le Noble F, Ahmed A, Gratacos E. Fetal growth restriction results in remodeled and less efficient hearts in children. Circulation 121: 2427–2436, 2010. 9. Frommelt PC, Ballweg JA, Whitstone BN, Frommelt MA. Usefulness of Doppler tissue imaging analysis of tricuspid annular motion for determination of right ventricular function in normal infants and children. Am J Cardiol 89: 610 –613, 2002. 10. Jackson RA, Gibson KA, Wu YW, Croughan MS. Perinatal outcomes in singletons following in vitro fertilization: a meta-analysis. Obstet Gynecol 103: 551–563, 2004. 11. Jamal F, Bergerot C, Argaud L, Loufouat J, Ovize M. Longitudinal strain quantitates regional right ventricular contractile function. Am J Physiol Heart Circ Physiol 285: H2842–H2847, 2003. 12. Jayet PY, Rimoldi SF, Stuber T, Salmon CS, Hutter D, Rexhaj E, Thalmann S, Schwab M, Turini P, Sartori-Cucchia C, Nicod P, Villena M, Allemann Y, Scherrer U, Sartori C. Pulmonary and systemic vascular dysfunction in young offspring of mothers with preeclampsia. Circulation 122: 488 –494, 2010. 13. Kassem E, Humpl T, Friedberg MK. Prognostic significance of 2-dimensional, M-mode, and Doppler echo indices of right ventricular function in children with pulmonary arterial hypertension. Am Heart J 165: 1024 –1031, 2013. 14. Kjaergaard J, Sogaard P, Hassager C. Right ventricular strain in pulmonary embolism by Doppler tissue echocardiography. J Am Soc Echocardiogr 17: 1210 –1212, 2004. 15. Koestenberger M, Nagel B, Ravekes W, Avian A, Heinzl B, Cvirn G, Fritsch P, Fandl A, Rehak T, Gamillscheg A. Reference values of tricuspid annular peak systolic velocity in healthy pediatric patients, calculation of z score, and comparison to tricuspid annular plane systolic excursion. Am J Cardiol 109: 116 –121, 2012. 16. Koestenberger M, Ravekes W, Everett AD, Stueger HP, Heinzl B, Gamillscheg A, Cvirn G, Boysen A, Fandl A, Nagel B. Right ventricular function in infants, children and adolescents: reference values of the tricuspid annular plane systolic excursion (TAPSE) in 640 healthy patients and calculation of z score values. J Am Soc Echocardiogr 22: 715–719, 2009. 17. Kriemler S, Jansen C, Linka A, Kessel-Schaefer A, Zehnder M, Schurmann T, Kohler M, Bloch K, Brunner-La Rocca HP. Higher pulmonary artery pressure in children than in adults upon fast ascent to high altitude. Eur Respir J 32: 664 –669, 2008. 18. Lang RM, Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, Picard MH, Roman MJ, Seward J, Shanewise JS, Solomon SD, Spencer KT, Sutton MS, Stewart WJ. Recommendations for chamber quantification: a report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 18: 1440 –1463, 2005. 19. Lazdam M, de la Horra A, Pitcher A, Mannie Z, Diesch J, Trevitt C, Kylintireas I, Contractor H, Singhal A, Lucas A, Neubauer S, Kharbanda R, Alp N, Kelly B, Leeson P. Elevated blood pressure in offspring born premature to hypertensive pregnancy: is endothelial dysfunction the underlying vascular mechanism? Hypertension 56: 159 –165, 2010. 20. Lewandowski AJ, Augustine D, Lamata P, Davis EF, Lazdam M, Francis J, McCormick K, Wilkinson AR, Singhal A, Lucas A, Smith NP, Neubauer S, Leeson P. Preterm heart in adult life: cardiovascular magnetic resonance reveals distinct differences in left ventricular mass, geometry, and function. Circulation 127: 197–206, 2013. 21. Lewandowski AJ, Bradlow WM, Augustine D, Davis EF, Francis J, Singhal A, Lucas A, Neubauer S, McCormick K, Leeson P. Right ventricular systolic dysfunction in young adults born preterm. Circulation 128: 713–720, 2013. 22. Lopez L, Colan SD, Frommelt PC, Ensing GJ, Kendall K, Younoszai AK, Lai WW, Geva T. Recommendations for quantification methods during the performance of a pediatric echocardiogram: a report from the

J Appl Physiol • doi:10.1152/japplphysiol.00533.2014 • www.jappl.org

1206

23. 24.

25.

26. 27. 28.

29.

30.

31.

32.

33.

34.

Cardiac Function and Assisted Reproductive Technology

Pediatric Measurements Writing Group of the American Society of Echocardiography Pediatric and Congenital Heart Disease Council. J Am Soc Echocardiogr 23: 465–495, 2010. McConnell MV, Solomon SD, Rayan ME, Come PC, Goldhaber SZ, Lee RT. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol 78: 469 –473, 1996. McDonald SD, Han Z, Mulla S, Murphy KE, Beyene J, Ohlsson A. Preterm birth and low birth weight among in vitro fertilization singletons: a systematic review and meta-analyses. Eur J Obstet Gynecol Reprod Biol 146: 138 –148, 2009. McQuillan BM, Picard MH, Leavitt M, Weyman AE. Clinical correlates and reference intervals for pulmonary artery systolic pressure among echocardiographically normal subjects. Circulation 104: 2797–2802, 2001. Mielke G, Benda N. Cardiac output and central distribution of blood flow in the human fetus. Circulation 103: 1662–1668, 2001. Nyboe Andersen A, Erb K. Register data on Assisted Reproductive Technology (ART) in Europe including a detailed description of ART in Denmark. Int J Androl 29: 12–16, 2006. O’Leary PW, Durongpisitkul K, Cordes TM, Bailey KR, Hagler DJ, Tajik J, Seward JB. Diastolic ventricular function in children: a Doppler echocardiographic study establishing normal values and predictors of increased ventricular end-diastolic pressure. Mayo Clin Proc 73: 616 –628, 1998. Okumura K, Slorach C, Mroczek D, Dragulescu A, Mertens L, Redington AN, Friedberg MK. Right ventricular diastolic performance in children with pulmonary arterial hypertension associated with congenital heart disease: correlation of echocardiographic parameters with invasive reference standards by high-fidelity micromanometer catheter. Circ Cardiovasc Imaging 7: 491–501, 2014. Pavlicek M, Wahl A, Rutz T, de Marchi SF, Hille R, Wustmann K, Steck H, Eigenmann C, Schwerzmann M, Seiler C. Right ventricular systolic function assessment: rank of echocardiographic methods vs. cardiac magnetic resonance imaging. Eur J Echocardiogr 12: 871–880, 2011. Pratali L, Allemann Y, Rimoldi SF, Faita F, Hutter D, Rexhaj E, Brenner R, Bailey DM, Sartori C, Salmon CS, Villena M, Scherrer U, Picano E, Sicari R. RV contractility and exercise-induced pulmonary hypertension in chronic mountain sickness: a stress echocardiographic and tissue Doppler imaging study. JACC Cardiovasc Imaging 6: 1287–1297, 2013. Pratali L, Rimoldi SF, Rexhaj E, Hutter D, Faita F, Salmon CS, Villena M, Sicari R, Picano E, Allemann Y, Scherrer U, Sartori C. Exercise induces rapid interstitial lung water accumulation in patients with chronic mountain sickness. Chest 141: 953–958, 2012. Rain S, Handoko ML, Trip P, Gan CT, Westerhof N, Stienen GJ, Paulus WJ, Ottenheijm CA, Marcus JT, Dorfmuller P, Guignabert C, Humbert M, Macdonald P, Dos Remedios C, Postmus PE, Saripalli C, Hidalgo CG, Granzier HL, Vonk-Noordegraaf A, van der Velden J, de Man FS. Right ventricular diastolic impairment in patients with pulmonary arterial hypertension. Circulation 128: 2016 –2025, 2011-2010, 2013. Rexhaj E, Bloch J, Jayet PY, Rimoldi SF, Dessen P, Mathieu C, Tolsa JF, Nicod P, Scherrer U, Sartori C. Fetal programming of pulmonary

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.



von Arx R et al.

vascular dysfunction in mice: role of epigenetic mechanisms. Am J Physiol Heart Circ Physiol 301: H247–H252, 2011. Rexhaj E, Paoloni-Giacobino A, Rimoldi SF, Fuster DG, Anderegg M, Somm E, Bouillet E, Allemann Y, Sartori C, Scherrer U. Mice generated by in vitro fertilization exhibit vascular dysfunction and shortened life span. J Clin Invest 123: 5052–5060, 2013. Rimoldi SF, Sartori C, Rexhaj E, Bailey DM, de Marchi SF, McEneny J, von Arx R, Cerny D, Duplain H, Germond M, Allemann Y, Scherrer U. Antioxidants improve vascular function in children conceived by assisted reproductive technologies: A randomized double-blind placebo-controlled trial. Eur J Prev Cardiol. In press. Rimoldi SF, Sartori C, Rexhaj E, Cerny D, von Arx R, Soria R, Germond M, Allemann Y, Scherrer U. Vascular dysfunction in children conceived by assisted reproductive technologies: underlying mechanisms and future implications. Swiss Med Wkly 144: w13973, 2014. Rimoldi SF, Sartori C, Seiler C, Delacretaz E, Mattle HP, Scherrer U, Allemann Y. High-altitude exposure in patients with cardiovascular disease: risk assessment and practical recommendations. Prog Cardiovasc Dis 52: 512–524, 2010. Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Louie EK, Schiller NB. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr 23: 685–713, 2010. Sartori C, Allemann Y, Trueb L, Delabays A, Nicod P, Scherrer U. Augmented vasoreactivity in adult life associated with perinatal vascular insult. Lancet 353: 2205–2207, 1999. Scherrer U, Allemann Y, Rexhaj E, Rimoldi SF, Sartori C. Mechanisms and drug therapy of pulmonary hypertension at high altitude. High Alt Med Biol 14: 126 –133, 2013. Scherrer U, Rimoldi SF, Rexhaj E, Stuber T, Duplain H, Garcin S, de Marchi SF, Nicod P, Germond M, Allemann Y, Sartori C. Systemic and pulmonary vascular dysfunction in children conceived by assisted reproductive technologies. Circulation 125: 1890 –1896, 2012. Valenzuela-Alcaraz B, Crispi F, Bijnens B, Cruz-Lemini M, Creus M, Sitges M, Bartrons J, Civico S, Balasch J, Gratacos E. Assisted reproductive technologies are associated with cardiovascular remodeling in utero that persists postnatally. Circulation 128: 1442–1450, 2013. Vogel M, Schmidt MR, Kristiansen SB, Cheung M, White PA, Sorensen K, Redington AN. Validation of myocardial acceleration during isovolumic contraction as a novel noninvasive index of right ventricular contractility: comparison with ventricular pressure-volume relations in an animal model. Circulation 105: 1693–1699, 2002. Weidemann F, Jamal F, Sutherland GR, Claus P, Kowalski M, Hatle L, De Scheerder I, Bijnens B, Rademakers FE. Myocardial function defined by strain rate and strain during alterations in inotropic states and heart rate. Am J Physiol Heart Circ Physiol 283: H792–H799, 2002. Williams CL, Bunch KJ, Stiller CA, Murphy MF, Botting BJ, Wallace WH, Davies M, Sutcliffe AG. Cancer risk among children born after assisted conception. N Engl J Med 369: 1819 –1827, 2013.

J Appl Physiol • doi:10.1152/japplphysiol.00533.2014 • www.jappl.org

Right ventricular dysfunction in children and adolescents conceived by assisted reproductive technologies.

Assisted reproductive technologies (ART) predispose the offspring to vascular dysfunction, arterial hypertension, and hypoxic pulmonary hypertension. ...
327KB Sizes 0 Downloads 9 Views