Background
The aim of this study was to determine morphologic correlates of early reintervention for recurrent coarctation in infants undergoing surgical repair in the current era.
Methods
Medical records of infants who underwent repair of coarctation were retrospectively reviewed. Z scores for aortic segments, relative aortic arch segmental dimensions (indexed to ascending or descending aortic dimension), and aortopulmonary index (the ratio of aortic to pulmonary annular diameter) were derived from preoperative echocardiograms.
Results
Eighty-seven patients underwent repair (median age, 13 days). Early arch reintervention (<1 year after surgery) was performed in 11. Lower aortopulmonary index and Z scores of the aortic annulus and sinotubular junction were associated with early reintervention. Aortopulmonary index < 0.6 was the best correlate (sensitivity, 72.7%; specificity, 73.7%; area under the curve, 0.732). Aortic arch dimensions were not correlated with early reintervention.
Conclusion
In the current era, aortopulmonary index rather than aortic arch hypoplasia is correlated with the need for reintervention for recurrent coarctation within 1 year of surgery.
Surgical repair of coarctation of the aorta in infancy can now be performed with very low operative mortality, in even the youngest and smallest patients. However, on long-term follow-up, recurrent coarctation may necessitate further aortic arch intervention, in the form of either percutaneous balloon angioplasty or surgery. In the previous surgical era, infants were shown to have the highest risk for reintervention, with a reoperation rate as high as 26% for those undergoing repair during the first year of life. In the modern surgical era, rates of reintervention after repair in infancy have improved to 11% to 14%, with a majority of reinterventions occurring within 1 year of initial repair.
Previous studies have suggested that hypoplasia of the aortic arch and isthmus may be correlated with outcomes in patients undergoing surgical repair. A defining characteristic of the modern era in coarctation surgery has been direct address of the hypoplastic aortic arch with the so-called extended end-to-end anastomosis, as opposed to either subclavian flap angioplasty or coarctectomy with simple end-to-end anastomosis. Given that this newer technique addresses aortic arch hypoplasia at the time of initial operation, the predictive value of preoperative aortic arch hypoplasia may be questioned. We therefore sought to determine whether aortic arch hypoplasia remains a risk factor for recurrent coarctation and to evaluate the role of other preoperative aortic dimensions in correlation with coarctation recurrence.
Methods
A retrospective review of medical records of all patients who underwent surgical repair of coarctation of the aorta during infancy at our institution from July 2002 through February 2009 was performed. This study was approved by the University of Arkansas for Medical Sciences Institutional Review Board. Patients with single-ventricle physiology were excluded. Data collected included patient demographics, associated cardiac diagnoses, and details of cardiac surgery, including the approach and type of repair. The surgical approach to the initial coarctation repair was based on the discretion of the surgeon, with a tendency to use median sternotomy and cardiopulmonary bypass for children with important associated cardiac defects to be simultaneously repaired or worse proximal aortic arch hypoplasia. Recurrent coarctation was defined as clinical (arm-leg systolic blood pressure gradient) and Doppler-derived peak gradient >20 mm Hg, with a diastolic runoff pattern in the descending aorta. Surgical or catheter-based reintervention was performed on all patients with recurrent coarctation. Early reintervention was defined as that performed within 1 year of initial surgery and was based on echocardiographic evidence of recurrent coarctation. Follow-up data regarding timing and type of reintervention were recorded.
An observer blinded to clinical outcomes analyzed preoperative echocardiograms offline. Measurements included the diameters of the pulmonary valve annulus, aortic valve annulus, aortic sinus, sinotubular junction, ascending aorta, proximal and distal transverse aortic arch, aortic isthmus, coarctation segment, and abdominal aorta ( Figure 1 ). The distance between the left subclavian artery and the carotid artery was also measured. These measurements were converted to Z scores on the basis of body surface area using regression equations published previously. The carotid-subclavian index was derived as a ratio of the aortic arch diameter at the left subclavian artery to the distance between the left subclavian artery and left common carotid artery. A novel index, called the aortopulmonary index (API), was calculated as the ratio of the aortic valve diameter to the pulmonary valve diameter. The diameters of the transverse aortic arch and aortic isthmus were also indexed to the diameters of the ascending aorta and abdominal aorta, as done in previous studies.
![](https://i0.wp.com/thoracickey.com/wp-content/uploads/2018/06/gr1-311.jpg?w=960)
Statistical Analysis
Actuarial freedom from early reintervention was determined for the entire sample using nonparametric Kaplan-Meier estimates. Univariate analysis was used to compare risk factors between status groups using nonparametric Wilcoxon and logistic regression analysis for continuous variables or Pearson’s χ 2 test for categorical variables. After identifying risk factors that were significantly different between the groups, locally weighted scatterplot smoothing regression analysis was used to determine whether a linear relationship existed. Receiver operating characteristic (ROC) curves were then used to analyze the value of an abnormal Z score (< −2) in correlation with the need for reintervention. For other indices, ROC analysis was also used to identify cutoff values that optimized sensitivity and specificity as a diagnostic test, and the area under the curve (AUC) was calculated. Kaplan-Meier survival analysis was also used to compare groups according to the previously determined cutoff values. Analysis of variance was used to evaluate any correlation between cardiac diagnosis and API or reintervention.
Results
Eighty-seven consecutive patients underwent repair of coarctation during infancy at our institution during the study period. There were no hospital deaths. The median age at initial surgery was 13 days (range, 2–166 days), and the median weight was 3.4 kg (range, 0.98–6.1 kg). With a median follow-up period of 50 months (range, 13–91 months), early arch reintervention was performed in 11 of 87 (12.6%). The median time to reintervention (10 transcatheter and 1 surgical) was 127 days (range, 3–154 days) from the time of initial surgery. There were no significant differences between patients who underwent reintervention and those who did not with regard to gender, race, age, weight, or associated cardiac diagnoses ( Table 1 ). Neither the surgical technique nor the surgical approach used in the initial repair had a significant effect on the risk for reintervention.
Variable | No reintervention ( n = 76) | Reintervention ( n = 11) | P |
---|---|---|---|
Demographics | |||
Male | 41 (54%) | 6 (55%) | 1.00 |
White | 57 (75%) | 9 (82%) | .56 |
Age (d) | 25.4 ± 29.4 | 13.9 ± 12.2 | .16 |
Weight (kg) | 3.5 ± 1.1 | 3.2 ± 0.6 | .13 |
Associated cardiac diagnoses | |||
Patent ductus arteriosus | 64 (84%) | 9 (82%) | .73 |
VSD | 30 (39%) | 4 (36%) | .95 |
Subaortic stenosis | 3 (4%) | 0 (0%) | .75 |
Bicuspid aortic valve | 18 (26%) | 3 (27%) | .60 |
Turner syndrome | 6 (8%) | 1 (9%) | .87 |
Down syndrome | 2 (3%) | 0 (0%) | .83 |
Shone’s complex | 3 (4%) | 1 (9%) | .08 |
Other cardiac anomaly ∗ | 8 (11%) | 0 (0%) | .45 |
Surgical details | |||
Lateral thoracotomy | 51 (67%) | 5 (45%) | .36 |
Midline sternotomy | 25 (33%) | 6 (55%) | .36 |
Simple end-to-end anastomosis | 17 (22%) | 2 (18%) | .73 |
Extended end-to-end anastomosis | 46 (61%) | 7 (64%) | .82 |
Subclavian flap angioplasty | 7 (9%) | 0 (0%) | .50 |
Patch angioplasty | 6 (8%) | 2 (18%) | .16 |
∗ Transposition of the great arteries, double-outlet right ventricle, tetralogy of Fallot, atrioventricular canal.
The morphologic variables aortic valve Z score ( Z -AOV), aortic sinotubular junction Z score ( Z -STJ), and API were all significantly correlated with early reintervention ( Table 2 ), on the basis of univariate analysis. There was an inverse relationship between API, Z -AOV and Z -STJ and the risk for reintervention ( Figures 2 A– 2 C). ROC analysis using cutoff values for these three variables is illustrated in Figure 3 . Values < −2 for Z -STJ and Z -AOV had acceptable specificity but poor sensitivity ( Z -STJ < −2: sensitivity, 45.4%; specificity, 88.1%; AUC, 0.603; Z -AOV < –2: specificity, 93.4%; sensitivity, 27.3%; AUC, 0.668). ROC analysis found that API < 0.6 was the best correlate of reintervention (AUC, 0.732), with 72.7% sensitivity and 73.7% specificity. Combining the three parameters of Z -STJ < −2, Z -AOV < −2, and API < 0.6 (AUC, 0.0763) did not significantly improve the utility of the model compared to API < 0.6 alone ( P = .10). Kaplan-Meier analysis on each of these variables ( Figures 4 A– 4 C) demonstrated a significant difference in the rates of reintervention when grouping subjects according to these cutoffs (API < 0.6: odds ratio, 7.5; 95% confidence interval, 1.8–30.9, P = .0019; Z -AOV < −2: odds ratio, 6.2; 95% confidence interval, 1.6–24.6; P = .0029; Z -STJ < −2: odds ratio, 5.3; 95% confidence interval, 1.1–26.6; P = .018). Of the risk factors evaluated, API < 0.6 was the best correlate of early recurrence of coarctation of the aorta requiring reintervention ( Figure 5 ). Neither aortic arch Z scores nor indices derived from aortic arch segmental dimensions were correlated with early reintervention ( Table 2 ).
Variable | No reintervention ( n = 76) | Reintervention ( n = 11) | P |
---|---|---|---|
Z scores | |||
Aortic valve | −0.4 ± 1.5 | −1.7 ± 1.7 | .01 |
Aortic sinus | −0.6 ± 1.2 | −1.4 ± 1.1 | .15 |
Sinotubular junction | −0.2 ± 1.1 | −1.4 ± 1.1 | .003 |
Ascending aorta | −2.3 ± 3.4 | −3.5 ± 0.9 | .08 |
Proximal aortic arch | −2.3 ± 1.4 | −2.5 ± 1.2 | .80 |
Aortic isthmus | −2.6 ± 1.2 | −2.8 ± 0.8 | .60 |
Coarctation segment | −5.3 ± 1.8 | −5 ± 1.4 | .84 |
Abdominal aorta | 0.3 ± 1.8 | 0.0 ± 1.2 | .92 |
Indexed values | |||
Carotid subclavian index | 1.1 ± 0.2 | 1.2 ± 0.2 | .98 |
API | 0.7 ± 0.6 | 0.6 ± 0.2 | .04 |
Proximal arch/ascending aorta | 0.8 ± 0.2 | 0.8 ± 0.1 | .95 |
Proximal arch/abdominal aorta | 0.9 ± 0.2 | 1.0 ± 0.3 | .87 |
Aortic isthmus/ascending aorta | 0.5 ± 0.1 | 0.6 ± 0.1 | .92 |
Aortic isthmus/abdominal aorta | 0.6 ± 0.1 | 0.6 ± 0.1 | .99 |
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