Coarctation of the Aorta in Infants: Does the Aortic Arch Grow After Repair? John L. Myers, MD, Brian A. McConnell, BS, and John A. Waldhausen, MD Division of Cardiothoracic Surgery, Department of Surgery, The Pennsylvania State University, The Milton S. Hershey Medical Center, Hershey, Pennsylvania
Infants with coarctation of the aorta frequently require a corrective operation during the first year of life. These patients frequently have a smaller than normal transverse aortic arch. Despite good repairs with different techniques, the proximal transverse aortic arch often remains smaller than normal. The hemodynamic molding theory predicts that growth of the aortic arch should occur when normal flow is established through the aortic arch. Preoperative and postoperative aortograms were reviewed in patients who underwent subclavian flap aortoplasty for the repair of coarctation. Patients were
divided into two groups. Subclavian flap aortoplasty was performed at 1 month of age or earlier in group I, and at more than 1 month but less than 1 year of age in group 11. Aortograms performed in patients without coarctation were used as age-matched controls (group 111). The transverse aortic arch in groups I and I1 did grow and were compared with the control group. Group I patients achieved more growth than those in group 11. No aortic arch gradients were present at postoperative follow-up.
S
Material and Methods
urgical repair of coarctation of the aorta in infants is usually accomplished by resection of the coarctation with end-to-end anastomosis or by subclavian flap aortoplasty (SFA). The incidence of recurrent coarctation has been greater in infants than in older children [l, 21. To enlarge the anastomosis and allow growth potential, some surgeons use the SFA [=I, whereas others use an extended end-to-end technique, resecting the coarctation and anastomosing the descending aorta to the underside of the aortic arch [7-lo]. The SFA is a longitudinal repair at the coarctation site that allows circumferential growth of native tissue and the subclavian flap [ l l , 121. Even though the coarctation site is repaired surgically, proximal regions of the aorta in the transverse aortic arch often remain small and, if growth does not occur, may require additional correction of the relative “stenosis” of the aortic arch. According to the hemodynamic molding theory it would be expected that these regions would grow postoperatively with a resultant increase in blood flow across the aortic arch. Our hypothesis is that when coarctation of the aorta is repaired early in life, the proximal aorta will grow. Our study was undertaken to test this hypothesis. Infants with tubular hypoplasia of the aortic arch proximal to the left subclavian artery require augmentation of their transverse aortic arch at the time of the initial operation and not simple end-to-end repair, SFA, or patch aortoplasty; therefore, these patients are not included in this series. Presented at the Twenty-eighth Annual Meeting of The Society of Thoracic Surgeons, Orlando, FL, Feb 3-5, 1992. Address reprint requests to Dr Myers, Division of Cardiothoracic Surgery, Department of Surgery, Penn State Children’s Hospital, The Milton S. Hershey Medical Center, PO Box 850, Hershey, PA 17033.
0 1992 by The Society of Thoracic Surgeons
(Ann Tkorac Surg 1992;54:869-75)
We reviewed the hospital records of all infants whose coarctation of the aorta was repaired by SFA (n = 70). To assess the growth of the aortic arch after operation we analyzed the aortograms of all patients who had both a preoperative and postoperative aortogram (n = 17). Most of these patients were operated on early in our series; in recent years, the wide application of two-dimensional and color Doppler echocardiography has minimized the need for routine preoperative and postoperative aortograms in patients with coarctation. The left anterior oblique projection of each aortogram was displayed on a screen and a tracing of the aortogram from the aortic annulus to the diaphragm was made. The left anterior oblique view minimizes the difference in magnification between the ascending and descending aorta by placing them in the same plane parallel to the radiographic image recorder. Measurements of the aortic diameter were made at six different regions on the tracing of each preoperative and postoperative aortogram (Figs 1A and lB, respectively). The six sites included: region 1: proximal, mid, and distal ascending aorta; region 2: between the innominate and left carotid arteries; region 3: between the left carotid and left subclavian arteries; region 4: level of coarctation (repair site); region 5: just distal to the coarctation (repair site); and region 6: descending aorta. The seventeen patients in this study were divided into two groups. Group I (n = 10) had SFA at the age of 1 month or younger, and group I1 patients (n = 7) had SFA after 1 month of age but before 1 year of age. Group I11 (n = 15) were patients who had aortograms while undergoing cardiac catheterization for the diagnosis of congenital heart defects that did not include patent ductus arteriosus 0003-4975/92/$5.00
870
MYERS ET AL AORTIC ARCH GROWTH
Ann Thorac Surg 1992;54:869-75
-I\
.
B
A
Fig 1. Diagram of aortogram preoperatively (A) and postoperatively (B).The numbers indicate the six regions where aortic diameters were measured.
or systemic to pulmonary artery shunt that could affect the differential growth of the aortic arch. They were used as age-matched controls. The three measurements of the ascending aorta (proximal, mid, distal) were averaged, and the individual regions 2 through 6 were compared with region 1 and expressed as a percentage (region 2 percentage = region 2/region 1 x 100). Within each of these three groups, the mean value for each region was calculated and reported as standard error of the mean. The three groups mean were compared using analysis of variance; a p value less than 0.05 was considered significant.
*
150
*p
Results Hernodynamic Data The most recent cardiac catheterization or two-dimensional Doppler echocardiographic study was reviewed. In
1
150
% of Control Group I
125
The age at the time of each aortogram and the age at operation were recorded. Hemodynamic data to determine aortic pressure gradients were obtained from the most recent cardiac catheterization or two-dimensional Doppler echocardiographic studies, or both.
0Group II
125
0.05 from Control
of Control
*
p
0.05 from Control
100
100
75
75
50
50
25
25 C
6
2
3
4
5
REGION Fig 2. Preoperative aortic dimensional relationships: Aortic diameter relationship preoperatively at regions 2, 3, 4, 5, and 6 expressed as a percentage of the ascending aortic diameter.
0
I 6
2
3
4
REGION
5
Fig 3 . One-year postoperative follow-up aortic dimensional relationships: Aortic diameter relationship at 1 year postoperatively at regions 2, 3 , 4, and 6 expressed as a percentage of the ascending aortic diameter.
871
MYERS ET AL AORTIC ARCH GROWTH
Ann Thorac Surg 1992;54:869-75
Table 1. Preoperative Aortic Dimensional Relationships Based on Region 1 and Age at Surgical Intervention" Group I
Region 2 3 4 5
0.59 0.49 0.23 0.98 0.81
6 a
Group I1 (11 mo)
((1 mo) 2 0.10 (75.6%)
2 0.06 (73.1%) f 0.08
(38.3%) f 0.11 (146.2%) f 0.11 (139.7%)
0.68 2 0.04 (87.2%) 0.56 2 0.05 (83.6%) 0.29 ? 0.11 (48.3%) 0.87 2 0.15 (129.9%) 0.66 0.08 (113.8%)
*
Group I11 (controls 1 7 mo) 0.78 0.67 0.60 0.67 0.58
2 0.06
0.05 f 0.07 f 0.06 0.03 f
*
p Value (I vs 111)
Infants with coarctation of the aorta frequently require a corrective operation during the first year of life. These patients frequently have a smaller than normal transverse aortic arch. Despite good repairs with different techniques, the proximal transverse aortic arch often remains smaller than normal. The hemodynamic molding theory predicts that growth of the aortic arch should occur when normal flow is established through the aortic arch. Preoperative and postoperative aortograms were reviewed in patients who underwent subclavian flap aortoplasty for the repair of coarctation. Patients were
divided into two groups. Subclavian flap aortoplasty was performed at 1 month of age or earlier in group I, and at more than 1 month but less than 1 year of age in group 11. Aortograms performed in patients without coarctation were used as age-matched controls (group 111). The transverse aortic arch in groups I and I1 did grow and were compared with the control group. Group I patients achieved more growth than those in group 11. No aortic arch gradients were present at postoperative follow-up.
S
Material and Methods
urgical repair of coarctation of the aorta in infants is usually accomplished by resection of the coarctation with end-to-end anastomosis or by subclavian flap aortoplasty (SFA). The incidence of recurrent coarctation has been greater in infants than in older children [l, 21. To enlarge the anastomosis and allow growth potential, some surgeons use the SFA [=I, whereas others use an extended end-to-end technique, resecting the coarctation and anastomosing the descending aorta to the underside of the aortic arch [7-lo]. The SFA is a longitudinal repair at the coarctation site that allows circumferential growth of native tissue and the subclavian flap [ l l , 121. Even though the coarctation site is repaired surgically, proximal regions of the aorta in the transverse aortic arch often remain small and, if growth does not occur, may require additional correction of the relative “stenosis” of the aortic arch. According to the hemodynamic molding theory it would be expected that these regions would grow postoperatively with a resultant increase in blood flow across the aortic arch. Our hypothesis is that when coarctation of the aorta is repaired early in life, the proximal aorta will grow. Our study was undertaken to test this hypothesis. Infants with tubular hypoplasia of the aortic arch proximal to the left subclavian artery require augmentation of their transverse aortic arch at the time of the initial operation and not simple end-to-end repair, SFA, or patch aortoplasty; therefore, these patients are not included in this series. Presented at the Twenty-eighth Annual Meeting of The Society of Thoracic Surgeons, Orlando, FL, Feb 3-5, 1992. Address reprint requests to Dr Myers, Division of Cardiothoracic Surgery, Department of Surgery, Penn State Children’s Hospital, The Milton S. Hershey Medical Center, PO Box 850, Hershey, PA 17033.
0 1992 by The Society of Thoracic Surgeons
(Ann Tkorac Surg 1992;54:869-75)
We reviewed the hospital records of all infants whose coarctation of the aorta was repaired by SFA (n = 70). To assess the growth of the aortic arch after operation we analyzed the aortograms of all patients who had both a preoperative and postoperative aortogram (n = 17). Most of these patients were operated on early in our series; in recent years, the wide application of two-dimensional and color Doppler echocardiography has minimized the need for routine preoperative and postoperative aortograms in patients with coarctation. The left anterior oblique projection of each aortogram was displayed on a screen and a tracing of the aortogram from the aortic annulus to the diaphragm was made. The left anterior oblique view minimizes the difference in magnification between the ascending and descending aorta by placing them in the same plane parallel to the radiographic image recorder. Measurements of the aortic diameter were made at six different regions on the tracing of each preoperative and postoperative aortogram (Figs 1A and lB, respectively). The six sites included: region 1: proximal, mid, and distal ascending aorta; region 2: between the innominate and left carotid arteries; region 3: between the left carotid and left subclavian arteries; region 4: level of coarctation (repair site); region 5: just distal to the coarctation (repair site); and region 6: descending aorta. The seventeen patients in this study were divided into two groups. Group I (n = 10) had SFA at the age of 1 month or younger, and group I1 patients (n = 7) had SFA after 1 month of age but before 1 year of age. Group I11 (n = 15) were patients who had aortograms while undergoing cardiac catheterization for the diagnosis of congenital heart defects that did not include patent ductus arteriosus 0003-4975/92/$5.00
870
MYERS ET AL AORTIC ARCH GROWTH
Ann Thorac Surg 1992;54:869-75
-I\
.
B
A
Fig 1. Diagram of aortogram preoperatively (A) and postoperatively (B).The numbers indicate the six regions where aortic diameters were measured.
or systemic to pulmonary artery shunt that could affect the differential growth of the aortic arch. They were used as age-matched controls. The three measurements of the ascending aorta (proximal, mid, distal) were averaged, and the individual regions 2 through 6 were compared with region 1 and expressed as a percentage (region 2 percentage = region 2/region 1 x 100). Within each of these three groups, the mean value for each region was calculated and reported as standard error of the mean. The three groups mean were compared using analysis of variance; a p value less than 0.05 was considered significant.
*
150
*p
Results Hernodynamic Data The most recent cardiac catheterization or two-dimensional Doppler echocardiographic study was reviewed. In
1
150
% of Control Group I
125
The age at the time of each aortogram and the age at operation were recorded. Hemodynamic data to determine aortic pressure gradients were obtained from the most recent cardiac catheterization or two-dimensional Doppler echocardiographic studies, or both.
0Group II
125
0.05 from Control
of Control
*
p
0.05 from Control
100
100
75
75
50
50
25
25 C
6
2
3
4
5
REGION Fig 2. Preoperative aortic dimensional relationships: Aortic diameter relationship preoperatively at regions 2, 3, 4, 5, and 6 expressed as a percentage of the ascending aortic diameter.
0
I 6
2
3
4
REGION
5
Fig 3 . One-year postoperative follow-up aortic dimensional relationships: Aortic diameter relationship at 1 year postoperatively at regions 2, 3 , 4, and 6 expressed as a percentage of the ascending aortic diameter.
871
MYERS ET AL AORTIC ARCH GROWTH
Ann Thorac Surg 1992;54:869-75
Table 1. Preoperative Aortic Dimensional Relationships Based on Region 1 and Age at Surgical Intervention" Group I
Region 2 3 4 5
0.59 0.49 0.23 0.98 0.81
6 a
Group I1 (11 mo)
((1 mo) 2 0.10 (75.6%)
2 0.06 (73.1%) f 0.08
(38.3%) f 0.11 (146.2%) f 0.11 (139.7%)
0.68 2 0.04 (87.2%) 0.56 2 0.05 (83.6%) 0.29 ? 0.11 (48.3%) 0.87 2 0.15 (129.9%) 0.66 0.08 (113.8%)
*
Group I11 (controls 1 7 mo) 0.78 0.67 0.60 0.67 0.58
2 0.06
0.05 f 0.07 f 0.06 0.03 f
*
p Value (I vs 111)
