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Ann Thorac Surg 2006;81:1420-1428
© 2006 The Society of Thoracic Surgeons
a Department of Cardiology and Cardiac Surgery, Royal Liverpool Childrens NHS Trust, Liverpool, United Kingdom
b Clinical Governance, Cardiothoracic Centre, Liverpool, United Kingdom
Accepted for publication August 25, 2005.
* Address correspondence to Dr Pandey, The Cardiothoracic Centre-Liverpool NHS Trust, Thomas Drive, Liverpool, L14 3PE United Kingdom (Email: raaginipandey{at}aol.com).
| Abstract |
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Methods: Data were collected retrospectively from the congenital cardiac surgical database at the institute.
Results: The median age at operation was 22 days (3 days–49 months). One hundred thirty-four patients had isolated coarctation while 265 children had complex coarctation. Maximum follow-up was 24 years (median, 14 years). Overall mortality over the whole duration of follow-up was 24.8%. Mortality for isolated coarctation at first intervention was 7.4% (operative mortality, 2.6%) while it was 12.8% for complex coarctation. At second intervention the mortality for isolated coarctation was 5%. For the second, third, and fourth interventions the mortality for complex coarctation was 25%, 25%, and 27%, respectively. The survival for isolated coarctation at 1, 5, 10, and 20 years was 94%, 93.2%, 92.4%, and 88.4%, respectively, while it was 74.6%, 66.3%, 63%, and 61.4%, respectively, for complex coarctation. Of the total patients, 15.3% had interventions for recoarctation. The incidence of recoarctation was 13.6% on those patients operated on in the first month of life, while it was 3.6% in older children. A percentage of 3.3% of patients continue to be hypertensive and require medication. There was a significant difference between the systolic blood pressure and anthropometric measurements between the arms. Despite this none of the patients complained of effect on lifestyle.
Conclusions: Despite improved early results the long-term mortality for coarctation remains high. Mortality is higher for complex coarctation as compared with isolated procedures. The incidence of recoarctation after SFA at long term is acceptable and is higher in patients operated on in the first month of life. The overall incidence of hypertension is quite low. Patients remained normotensive when operated upon at the age of 0.9 months. The SFA, no doubt, effects the limb development; however it does not cause limitation in the lifestyle.
| Introduction |
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| Material and Methods |
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Those patients having coarctation without any associated cardiac anomaly except a patent ductus arteriosus (PDA) were classified as having isolated coarctation, while those having associated cardiac anomaly ±PDA were classified as having complex coarctation. The diagnosis was made clinically and confirmed by diagnostic catheterization and transthoracic echocardiography up to 1975; thereafter, only patients with associated anomalies continued to receive catheterization.
Patient Characteristics
There were 260 males and 139 females. Two hundred twenty-six patients were aged 1 month or less at the first intervention. Of 399 patients 134 had isolated coarctation while 265 had complex coarctation. The distribution of associated anomalies is shown in Table 1
. The median age at subclavian flap aortoplasty was 22 days (3 days–49 months). The median age at first operation was 27 days (12 days–14.6 months) in patients having isolated coarctation, while it was 16.8 days (9.9–72 days) in patients with complex coarctation.
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Three hundred thirty-seven patients underwent SFA only as their first intervention while 62 patients had an associated operative procedure in addition to the SFA. The distribution of associated procedures at first intervention is as shown in Table 2. In those patients who had only coarctation tackled at the first intervention, the operation was performed through a left posterolateral thoracotomy through the fourth intercostal space. This approach was also used in patients who had a pulmonary artery band (PAB) in addition to SFA. In others who had an additional cardiac procedure the coarctation was tackled through a median sternotomy on cardiopulmonary bypass.
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Follow-Up
All patients were seen by the referring cardiologist at The Royal Liverpool Sick Childrens NHS Trust or by one of the cardiologists in an outreach clinic. The median follow-up was 14.0 years (9.2–17.3 years). The maximum follow-up was 24 years; 90% of patients were followed up for 2.7 years or longer, 75% for 5.7 years or longer, 25% for 14 years or longer, and 10% for 16.8 years or longer.
At follow-up recoarctation was defined as a resting pressure gradient of more than 20 mm Hg between the arm and leg blood pressures measured noninvasively. Presence of recoarctation has been confirmed by the presence of a diastolic tail to the continuous wave Doppler signal in the descending thoracic aorta since 1975.
Interventions performed during follow-up were classified into three categories. Category I was intervention for recoarctation alone, category II was intervention for associated procedure alone, and category III was for recoarctation as well as associated procedure done in the same sitting. The interventions were further divided into surgical interventions and catheter-based interventions. Hypertension was defined as blood pressure above the 95th percentile for age at last follow-up in three consecutive measurements.
A study undertaken by this institute previously showed a disparity in anthropometric measurements between both the upper limbs in all the patients [8]. Assuming that growth disparity did exist between upper limbs in all the patients, we believed it important to assess the patients perception of this disparity and the significance of its effect on lifestyle in the long term. This was achieved by means of a written questionnaire sent to all survivors.
Statistical Analysis
Continuous variables are presented as median with 25th and 75th centiles and categorical variables as percentages with 70% confidence limits. The possibility that the differences were due to chance was analyzed univariately using the Wilcoxon rank sum or
2 tests as appropriate.
The time-related distributions of death and recoarctation were explored nonparametrically using the product limit method of Kaplan and Meier [9] and modeled parametrically in the hazard function domain [10]. Risk factors for death and recoarctation were sought using multivariable hazard function regression analysis. The variables used for analysis are depicted in Appendices 1 and 2, respectively. Importantly, the influence of interventions performed subsequent to SFA on the outcome death was assessed from the incorporation of such interventions as time-varying covariables.
| Results |
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The mortality at any time for patients with isolated coarctation was 7.4% (5.1–10.5%) (4 operative deaths) as opposed to 15.8% (13.5–18.5%) in patients with complex coarctation (Table 2). The type of surgical procedures at second, third, and fourth intervention and associated mortality for both isolated and complex coarctation is depicted in Tables 3, 4, and 5
, respectively. The mortality at every intervention was higher in patients with complex coarctation as compared with the isolated coarctation group (25% vs 5%, 25% vs 0, and 27% vs 0, respectively).
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Long-Term Left Arm Sequelae
At follow-up there was a significant difference between the systolic blood pressure between the left arm (median: 90 mm Hg; 70–130 mm Hg) as compared with the right arm (median: 106 mm Hg; 90–110 mm Hg) (p < 0.005).
Two hundred fifty-two (84%) survivors responded to the questionnaire. Of these, 28.8% were aware of the difference in muscular development in the left arm as compared with the right arm, while 24.6% were aware of the disparity in the length between the two arms. Awareness of disparity in the muscular development between the arms as well as disparity in the limb lengths was significantly higher in patients operated upon after the first month of life. These findings were statistically significant (p = 0.01 and p = 0.02, respectively). Despite the awareness of the disparity none of the patients complained of any effect of this on their lifestyle.
| Comment |
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Notwithstanding the morphology, the popularity of operative techniques has waxed and waned from one decade to another. This study is an attempt to evaluate the results of SFA over 29 years on the background of this continuous change.
Mortality
The overall mortality at the end of follow-up was 24.8%. The mortality was significantly higher in the complex coarctation group as compared with the isolated coarctation at each intervention. The morphologic factors associated with higher mortality were single ventricle, hypoplastic left ventricle, corrected TGA, complex TGA, and multiple VSD. These lesions standing alone are often associated with poor cardiac function, acute presentation, and a need for emergency surgery. This has also been observed in other series [15]. Of note is the fact that after the first intervention the mortality for complex coarctation remains constant, at around 25% for every subsequent intervention. Though the early mortality has been reduced the long-term mortality continues to be high and this compares with other reported coarctation series [16].
The important aspect of this study is the fact that the influence of each subsequent intervention on outcome death was assessed by incorporating these interventions as time-varying covariables. This helped to differentiate the late deaths after coarctation repair from the early deaths associated with any intervention. Of all the operative interventions assessed, PAB, repair of TGA, valve repair or replacement, and cavopulmonary anastomosis had a significant adverse effect on mortality after SFA. Subsequent interventions to tackle recoarctation as well as the associated anomaly as a combined procedure had a significantly higher mortality as compared with repeat interventions for recoarctation alone or for associated anomaly alone (Table 6). It is interesting to note that PAB performed as a combined procedure at first intervention as well as performed alone as a second intervention had a significantly adverse effect on mortality. One reason for this might be the posterior malalignment of the conal septum, which is seen in as high as 47% of patients with coarctation and VSD and can be present even in the absence of a VSD [17, 18]. Not only can this be one of the causes of LVOTO in the postoperative period, it can also lead to double ventricular outflow obstruction if these patients undergo PA banding. The ensuing ventricular failure can lead to death especially in patients with univentricular hearts. This is borne out by 100% mortality in patients with univentricular hearts in this series.
Survival
The survival for isolated coarctation is better than complex coarctation at any time. The actuarial survival curves reinforce the fact that despite good early results the long-term survival of patients is low [Fig 3]. The reported probability of survival at 44 years after repair is 73% [19]. History of previous surgery had an adverse affect on survival.
Recoarctation
The reported incidence of recoarctation varies 5% to 30% [20]. The incidence of intervention for recoarctation in this series has been 15.3%. Though our figures lie within the reported limits, we cannot draw parallels between our series and the reported literature because of the variations in factors such as age at operation and duration of follow-up. The important feature of this series lies in the fact that it reports incidence of recoarctation in a large number of patients, all of whom were exclusively repaired with SFA. It is clear that some patients will continue to remain at risk for recoarctation irrespective of the type of repair. This can be explained on the basis of anatomic studies that show the median distal transverse arch and the isthmus diameter in coarctation patients to fall at the 15th to 18th percentiles of the normal, respectively. The distal transverse arch and isthmus in patients with discrete coarctation are also significantly smaller than normal patients of the same age and body surface area [20]. In fact, most patients with coarctation have arches that are smaller than normal but not quite hypoplastic [12]. Also, there are few arches that fail to grow despite the repair or do not grow to the same extent as normal because of the abnormal tissue in the aortic arch [21].
Despite good coarctation repair "obstruction" is seen due to growth failure of the transverse arch proximal to the site of repair rather then "recoarctation" at the site of repair [22]. Recoarctation after SFA is reported to occur within the first year after repair due to involution of the ductal tissue left behind, especially in infants [23]. In our series freedom from recoarctation at an interval of 1 year is 96.1%. Though the recoarctation rate is significantly higher in neonates (
4 weeks of age) as compared with older children (13.6% vs 3.6%, p= 0.001) in multivariate analysis age did not emerge as a risk factor for recoarctation. This might be explained on the basis of the fact that patients operated upon at a younger age fell in the morphologically worse part of the spectrum, with borderline arches and complex anomalies. It could be the adverse morphology of the coarctation segment rather than the age affecting recoarctation. Use of SFA in patients with worse morphology was done with the belief that relieving the coarctation would increase the antegrade blood flow and stimulate the growth of these arches. Use of SFA for hypoplastic distal arches has been reported by others [24].
Anatomic risk factors associated with significantly higher risk of recoarctation were associated hypoplastic arch and a transposition of the great arteries with a Taussig-Bing anomaly. The performance of PAB emerged as the most significant risk factor for recoarctation in multivariate analysis, but its effect was confined to those interventions performed at medium term; at long term it did not have any effect on recoarctation. The only way we can explain this is the fact that PAB acts as a surrogate for anatomic lesions with left to right shunts. In patients with PAB though the left to right shunting is reduced it is still not abolished completely resulting in diminished antegrade flow through the aorta. Hence, even though the coarctation is repaired because of decreased antegrade flow the growth potential is not realized. Thus, in patients with associated anomaly causing left to right shunt it would be advisable to repair the anomaly early to increase antegrade flow and facilitate growth.
Hypertension
The incidence of hypertension in this series has been fairly low as compared with other series, with only 3.3% patients needing medication at the last follow-up [25]. There is no doubt that devascularization of the left arm does have an effect on the anthropometric measurements as well as the blood pressure in the left arm. However, it has not affected the lifestyle of the patients in this series. We have also found that earlier age at surgery is associated with a decreased awareness of this fact.
Limitations of the Study
This being a retrospective observational study objective data regarding the size of the aortic arch were not available in all the patients. Also, the study includes patients operated upon by different surgeons at different time intervals. Since only 252 (84%) survivors returned the questionnaire for the assessment of limb complications the follow-up for limb complications is not complete.
Conclusion
Despite improved early results the long-term mortality for coarctation repair using SFA remains high. Mortality is higher for complex coarctation as compared with isolated procedures. The incidence of recoarctation after SFA at long term is acceptable and comparable with other series; however, it is higher in patients operated on in the first month of life. The overall incidence of hypertension is quite low. Patients remained normotensive when operated upon at the age of 0.9 months. The SFA no doubt effects the limb development; however, it does not cause limitation in the lifestyle.
| Appendix 1 |
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Early phase: intercept = 0.1, delta = 0, thalt = 1.231, nu = 2.106, mu = 1.
aLog transfer (number of operations to date + 1). All variables other than number of operations to date are dichotomous. (yes/no).
ASD = atrial septal defect; CP = cavopulmonary; cTGA = corrected transposition of great arteries; LV = left ventricle; SE = standard error; VSD = ventricular septal defect.
| Appendix 2 |
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Early Phase: intercept = 0.081, Rho = 12.321, Nu = 0.779, Mu = 1. Constant phase: Intercept = 4.578 x 10–4; log likelihood = 407.213.
All variables are dichotomous (yes/no). AV = atrioventricular; LVOTO = left ventricular outflow tract obstruction; PA = pulmonary artery; SE = standard error.
| Acknowledgments |
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| References |
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