Correlation of pediatric echocardiographic Doppler and catheter-derived valvar aortic stenosis gradients and the influence of aortic regurgitation

Aortic valve repair for congenital abnormalities of the aortic valve

BACKGROUND

Due to shortcomings of any valve replacement, repairing and retaining the native valve may be beneficial for congenital aortic valve disease.

METHODS

Retrospective review of data and follow-up of aortic valve repair from a single institution.

RESULTS

From 1993 to 2001, 56 patients underwent aortic valve repair [median age 13.4 years (range 1 day to 45 years)]. The predominant aortic valve lesion was mixed aortic stenosis/aortic insufficiency 25 (45%), aortic insufficiency 24 (43%) and aortic stenosis 7 (13%). Repair techniques included sub-commissural plication 36 (64%), commissurotomy 24 (43%), cusp plication 15 (27%), pericardial patch cusp extension 8 (14%) and resuspension of commissures 4 (7%). Most patients (88%) required a combination of techniques; 61% required additional procedures. Hospital survival was 55/56 [98%; (95% CI 91-100%)] no patient was discharged on anticoagulation for aortic valve pathology. Fifty-three patients [95%; (95% CI 85-98%)] remain alive after a median follow-up of 37 months; four survivors required aortic valve replacement and two required repeat aortic valve repair [84%; (95% CI 72-91%) reintervention-free survival].

CONCLUSIONS

(1) In this study, aortic valve repair for congenital abnormalities avoided reoperation in the majority of patients, avoided anticoagulation and retained growth potential of the valve. (2) Repeat aortic valve repair or replacement was used to treat subsequent valve deterioration.

Balloon aortic valvoplasty in paediatric patients: progressive aortic regurgitation is common

OBJECTIVE

To evaluate immediate and midterm results after balloon valvoplasty in a paediatric population with congenital aortic stenosis, giving special consideration to aortic regurgitation.

DESIGN

Retrospective study.

SETTING

Two tertiary referral centres for paediatric cardiology.

PATIENTS

70 consecutive patients, with an age range of 0-16.4 years. Group A infants < 3 months old (n = 21). Group B children > 3 months old (n = 49). Median follow up time was 19.8 months, range 0-158 months.

INTERVENTION

All patients underwent balloon aortic valvoplasty. The balloon to annulus ratio was selected at a mean of 0.90 (range 0.67-1.0).

MAIN OUTCOME MEASURES

Doppler gradients and degree of aortic regurgitation.

RESULTS

The pressure gradient dropped significantly with the intervention and increased mildly at follow up. Freedom from relevant aortic regurgitation (that is, moderate and severe) was initially lower in group A (75% v 90% after one month) but after two years the difference between the two groups was not significant (50% v 61%). Freedom from reintervention was significantly lower in group A (with 35% v 80%) after three years.

CONCLUSION

Aortic balloon valvoplasty is safe and effective but has a high rate of early reintervention in infants with critical aortic stenosis. The major long term problem is progressive aortic regurgitation, which does not seem to be prevented by the use of small balloons.

Comparison of simultaneous invasive and noninvasive measurements of pressure gradients in congenital aortic valve stenosis

PURPOSE

Congenital aortic valve stenosis is a common problem in pediatric cardiology. The catheter peak to peak systolic gradient is the accepted standard used for prognosis and intervention, but noninvasive correlation in pediatric patients is frequently associated with underestimation or overestimation of this gradient. The purpose of this study was to compare different noninvasive measurements with simultaneous catheter gradients to identify which best predicts the catheter peak to peak gradient.

METHODS

Twenty-five simultaneous Doppler and catheter measurements of aortic stenosis gradient were performed in 14 children (all 14 before valvuloplasty and 11 after valvuloplasty). Noninvasive estimates of pressure gradient were compared with catheter measurements with linear regression and Bland-Altman analysis.

RESULTS

The Doppler peak instantaneous pressure gradient overestimated the catheter peak to peak gradient but correlated well with the catheter peak instantaneous gradient. The Doppler mean systolic gradient correlated well with the catheter peak to peak gradient at low gradients and underestimated higher catheter gradients but agreed well at all levels with the catheter mean gradient. The modification of a catheter-derived correlation equation produced good correlation with the catheter peak to peak gradient (slope, 1.14; intercept, -1.8; R, 0.92), as did the use of estimated pressure recovery (slope, 1.04; intercept, 5.0; R, 0.94), calculated from a defined fluid mechanic equation.

CONCLUSION

The catheter peak to peak gradient can be accurately estimated noninvasively using estimated pressure recovery or correlation equations incorporating Doppler measurements.

Non-invasive determination of the systolic peak-to-peak gradient in children with aortic stenosis: validation of a mathematical model

Doppler derived systolic pressure gradients have become widely applied as noninvasively obtained estimates of the severity of aortic valvar stenosis. There is little correlation, however, between the Doppler derived peak instantaneous gradient and the peak-to-peak gradient obtained at catheterisation, the latter being the most applied variable to determine severity in children. The purpose of this study was to validate a mathematical model based on data from catheterisation which estimates the peak-to-peak gradient from variables which can be obtained by noninvasive means (Doppler derived mean gradient and pulse pressure), according to the formula: peak-to-peak systolic gradient = 6.02+/-1.49*(mean gradient)-0.44*(pulse pressure). Simultaneous cardiac catheterization and Doppler studies were performed on 10 patients with congenital aortic valvar stenosis. Correlations between the gradients measured at catheter measured, and those derived by Doppler, were performed using linear regression analysis. The mean gradients correlated well (y = 0.67 x +11.11, r = 0.87, SEE = 6 mm Hg, p = 0.001). The gradients predicted by the formula also correlated well with the peak-to-peak gradients measured at catheter (y = 0.66 x +14.44, r = 0.84, SEE = 9 mm Hg, p = 0.002). The data support the application of the model, allowing noninvasive prediction of the peak-to-peak gradient across the aortic valvar stenosis.