Aortic regurgitation (AR) has increased in the pediatric population because of the expanded use of new surgical and hemodynamic procedures. Unfortunately, the exact timing for operation in patients with AR is still debated. Conventional echocardiographic parameters, left ventricular (LV) dimensions and the LV ejection fraction, have limitations in predicting early LV dysfunction. Two-dimensional strain imaging, an emerging ultrasound technology, has the potential to better study those patients. The aim of this study was to assess the prognostic value of 2-dimensional longitudinal strain in young patients with congenital isolated moderate to severe AR. Twenty-six young patients with asymptomatic AR (aged 3 to 16 years) were studied. The mean follow-up duration was 2.9 ± 1.2 years (range 0.5 to 6). Baseline LV function by speckle-tracking and conventional echocardiography in patients with stable disease was compared with that in patients with progressive AR (defined as development of symptoms, increase in LV volume ≥15%, or decrease in the LV ejection fraction ≤10% during follow-up). LV ejection fractions were similar between groups. The jet area/LV outflow tract area ratio was significantly increased in patients with AR with progressive disease (31.2 ± 5.6% vs 39.2 ± 3.8%, p <0.001). The peak transmitral early velocity/early diastolic mitral annular velocity ratio was significantly increased in patients with progressive AR (p = 0.001). LV average longitudinal strain was significantly reduced in patients with progressive AR compared to those with stable AR (−17.8 ± 3.9% vs −22.7 ± 2.7%, p = 0.001). On multivariate analysis, the only significant risk factor for progressive AR was average LV longitudinal strain (p = 0.04, cut-off value >−19.5%, sensitivity 77.8%, specificity 94.1%, area under the curve 0.889). In conclusion, 2-dimensional strain imaging can discriminate young asymptomatic patients with progressive AR. This could allow young patients with AR to have a better definition of surgical timing before the occurrence of irreversible myocardial damage.
In recent years, aortic regurgitation (AR) has increased in the pediatric population because of the expanded use of new surgical and hemodynamic procedures. Unfortunately, the exact timing of surgery in patients with AR is still debated. A desirable goal is to discriminate among asymptomatic patients those with subclinical left ventricular (LV) dysfunction. Conventional echocardiographic parameters, LV dimensions and the LV ejection fraction, have limitations in predicting early LV dysfunction. Strain imaging, an emerging ultrasound technology, has been added to our capabilities and has the potential to better study these patients. Young patients with congenital isolated AR may offer the unique clinical opportunity to study the effect of pure chronic volume overload on the left ventricle, without the possible influence of other co-morbidities. Thus, the aim of our study was to assess myocardial longitudinal deformation properties in young patients with congenital isolated moderate to severe AR and to evaluate their prognostic value.
Methods
We studied asymptomatic young patients (aged ≤16 years) with congenital isolated AR of moderate to severe degree referred to our outpatient clinic. Inclusion criteria were New York Heart Association functional class I, sinus rhythm, and pure and moderate to severe AR by echocardiographic criteria (jet area/LV outflow tract area >25%, vena contracta >5 mm) with normal LV ejection fractions (≥55%). Exclusion criteria were acute AR, previous heart surgery or valve implantation, aortic stenosis (mean gradient ≥20 mm Hg), more than mild mitral valve disease, arrhythmias, history of rheumatic fever, and history of aortic balloon dilatation. Patients receiving drug treatment were excluded. Thus, 26 patients (19 male, median age 15 years, range 3 to 16) were included in the study. Patients were followed for a mean follow-up period of 2.9 ± 1.2 years (range 0.5 to 6). The study protocol was approved by our local ethical committee. Both parents of studied patients gave their written informed consent to participate in the study.
Echocardiographic examinations were performed using Vivid 7 and E9 machines (GE Vingmed Ultrasound AS, Horten, Norway). Blinded offline analysis was performed using EchoPAC PC version 6.1.1 (GE Vingmed Ultrasound AS). For all measurements, the average of 3 heart cycles was used. LV dimensions were assessed using M-mode echocardiography in a standard fashion. LV volumes, vena contracta, and jet width were calculated as previously described.
Using pulsed-wave Doppler, mitral inflow velocities, peak early diastolic velocity (E), peak late diastolic velocity, their ratio (E/A), and early diastolic wave deceleration time were measured. Myocardial velocities were obtained from the apical 4-chamber view. A 3-mm sample volume was placed at the lateral mitral annulus. The peak velocities at the lateral annulus during early diastole (Em) were measured. The E/Em ratio was calculated.
Longitudinal deformation was analyzed on 2-dimensional grayscale loops using the EchoPAC software. A global measure of total systolic strain was calculated as previously described.
For this study, a patient exhibiting (1) the development of symptoms, (2) a relative increase in LV end-diastolic volume indexed for body surface area of ≥15%, or (3) a relative decrease in the LV ejection fraction of ≥10% was classified as having “progressive” AR and considered a candidate for surgical therapy; otherwise, patients were considered “stable.”
All analyses were performed using MedCalc for Windows release 11.3.3.0 (MedCalc Software, Mariakerke, Belgium). The distributions of continuous parameters were determined using the D’Agostino-Pearson test. Parameters with normal distributions are expressed as mean ± SD, and those with non-normal distributions are expressed as median (interquartile range). Continuous variables were compared using the Mann-Whitney U test or the unpaired Student’s t test as appropriate. Fisher’s exact test was used for qualitative variables. Ascendant stepwise logistic regression was used to determine the independent risk factors for progressive AR, with p = 0.05 to enter and p = 0.10 to remove. Receiver-operating characteristic curve analyses were performed to determine the areas under the curves for independent risk factors detected by ascendant stepwise logistic regression, and optimal cutoffs were selected by optimizing sensitivity plus specificity. For reproducibility analysis, in 13 randomly selected patients, the coefficient of variation was calculated as the SD of the difference between repeated measurements divided by the mean value. Cumulative survival curves were performed using the Kaplan-Meier method. Statistical significance was established at p <0.05.
Results
None of the studied patients was lost during the follow-up period. During the 2.9 ± 1.2 year follow-up period, 9 patients (34.6%) had progressive AR and underwent surgical repair. Indications for surgery were the development of symptoms (n = 3; New York Heart Association class II or III) and the development of LV dilatation (n = 4) or LV dysfunction (n = 2); in 4 patients, there was >1 indication. Baseline general and echocardiographic characteristics of the studied patients are presented in Table 1 .
| Patient | AR | Gender | Age (years) | BMI (kg\m 2 ) | PP (mm Hg) | LVEDDI (mm/m 2 ) | LVMI (g/m 2 ) | LVEDVI (ml/m 2 ) | LV EF (%) | Jet Area/LVOT Area | VC (mm) | E/Em | Average LV Longitudinal Strain (%) | Follow-Up (years) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Stable | M | 10.0 | 22.5 | 42.0 | 38.5 | 116.9 | 115.4 | 67 | 37 | 8.7 | 4.7 | −23.6 | 2 |
| 2 | Stable | M | 10.0 | 14.6 | 39.0 | 43.2 | 124 | 129.5 | 62 | 35.2 | 8.8 | 3.7 | −26.8 | 2 |
| 3 | Stable | M | 10.0 | 19.3 | 57.0 | 32.2 | 115.9 | 96.0 | 65 | 31.6 | 6.9 | 3.7 | −21 | 2 |
| 4 | Stable | M | 12.0 | 19.9 | 51.0 | 37 | 87.2 | 111.5 | 69 | 25.8 | 5.4 | 4.7 | −27.2 | 4 |
| 5 | Stable | M | 12.0 | 19.5 | 52.0 | 34.2 | 78.4 | 102.7 | 63 | 26 | 5.3 | 3.1 | −24.5 | 3 |
| 6 | Stable | M | 13.0 | 23.5 | 45.0 | 29.4 | 116 | 88.2 | 68 | 32.7 | 7.2 | 3.6 | −22 | 3 |
| 7 | Stable | M | 14.0 | 20.3 | 50.0 | 29.8 | 122 | 90.0 | 64 | 33.3 | 7 | 3.7 | −21.2 | 6 |
| 8 | Stable | F | 14.0 | 20.0 | 50.0 | 34.8 | 114.9 | 104.5 | 65 | 34.1 | 7.5 | 3.8 | −18.7 | 3 |
| 9 | Stable | M | 16.0 | 22.0 | 67.0 | 32.9 | 106.5 | 98.6 | 66 | 25.7 | 5.5 | 4.3 | −21.1 | 4 |
| 10 | Stable | M | 16.0 | 22.8 | 80.0 | 33.1 | 121.8 | 99.3 | 68 | 26 | 5.1 | 2.3 | −23.2 | 5 |
| 11 | Stable | M | 16.0 | 24.6 | 106.0 | 33.2 | 132.1 | 99.5 | 60 | 43 | 9 | 8.1 | −21 | 2 |
| 12 | Stable | M | 16.0 | 20.7 | 60.0 | 31.3 | 111.4 | 93.9 | 62 | 26 | 5.3 | 2.8 | −23.5 | 2 |
| 13 | Stable | F | 16.0 | 19.4 | 46.0 | 31.3 | 74.3 | 93.8 | 68 | 25 | 5.4 | 4 | −19.5 | 2 |
| 14 | Stable | M | 16.0 | 25.8 | 75.0 | 29.2 | 122 | 87.7 | 60 | 30.5 | 7.8 | 3.6 | −27.2 | 3 |
| 15 | Stable | M | 16.0 | 22.7 | 52.0 | 31.6 | 114.9 | 94.9 | 62 | 33.2 | 7.3 | 5 | −24.7 | 4 |
| 16 | Stable | M | 16.0 | 27.8 | 58.0 | 25.7 | 100.5 | 77.2 | 65 | 40 | 9.8 | 3.7 | −20.5 | 3 |
| 17 | Stable | F | 16.0 | 19.6 | 60.0 | 44.3 | 124.3 | 132.8 | 65 | 25.5 | 7.1 | 3.1 | −19.6 | 2 |
| 18 | Progressive | F | 3.0 | 12.2 | 40.0 | 76 | 114 | 90.0 | 64 | 37.0 | 5.5 | 5.5 | −18 | 1.5 |
| 19 | Progressive | M | 10.0 | 17.6 | 60.0 | 34.2 | 78.4 | 102.6 | 68 | 37.0 | 6.0 | 5.5 | −18.6 | 3 |
| 20 | Progressive | M | 10.0 | 16.7 | 40.0 | 44 | 109.7 | 131.7 | 66 | 42.6 | 8.1 | 6.0 | −24 | 3 |
| 21 | Progressive | F | 12.0 | 16.4 | 40.0 | 43.3 | 113 | 130.0 | 60 | 40.0 | 8.0 | 4.5 | −9.7 | 3 |
| 22 | Progressive | F | 15.0 | 21.8 | 50.0 | 39.3 | 115 | 117.9 | 62 | 39.5 | 7.3 | 4.0 | −15 | 4 |
| 23 | Progressive | F | 16.0 | 26.2 | 40.0 | 33.4 | 113.1 | 100.3 | 60 | 31.3 | 6.0 | 3.4 | −17.4 | 0.5 |
| 24 | Progressive | M | 16.0 | 22.8 | 65.0 | 33.7 | 142.6 | 101.1 | 67 | 42.9 | 9.0 | 5.0 | −18.9 | 2 |
| 25 | Progressive | M | 16.0 | 28.3 | 60.0 | 30.1 | 115 | 90.2 | 65 | 38.9 | 5.1 | 7.0 | −20.7 | 5 |
| 26 | Progressive | M | 16.0 | 25.1 | 50.0 | 33 | 186 | 99.7 | 68 | 43.3 | 7.5 | 5.8 | −18 | 2 |
| p value | NS | NS | NS | NS | NS | NS | NS | NS | <0.001 | NS | 0.001 | 0.001 | NS |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
