Ann Thorac Surg 2002;74:1625-1630
© 2002 The Society of Thoracic Surgeons
Original article: cardiovascular
Anomalous origin of the left coronary artery from the pulmonary artery: results of surgical correction in five infants
Ragini Pandey, FRCS (Ed)a,
Giovanna Ciotti, MDa,
Marco Pozzi, MDa*
a Cardiac Unit, Royal Liverpool Children’s Hospital, Alder Hey, Liverpool, United Kingdom
Accepted for publication May 29, 2002.
* Address reprint requests to Dr Pozzi, Cardiac Unit, Royal Liverpool Children’s Hospital, Alder Hey, Eaton Rd, Liverpool L12 2AP, UK.
e-mail: mpozzi75{at}hotmail.com
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Abstract
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BACKGROUND: Five infants operated on for anomalous origin of the left coronary artery from the pulmonary artery were retrospectively analyzed. The mean age at operation was 12 ± 6.7 weeks (95% confidence interval, 3.5 to 20 weeks), and mean weight at operation was 4.43 ± 0.68 kg (95% confidence interval, 3.7 to 5.27 kg). All babies presented in infancy with left ventricular failure. Three had evidence of ischemia with left ventricular strain, and two had Q waves in anterolateral leads on electrocardiograph. Cross-sectional echocardiography showed dilated left ventricles with poor contractility in all babies with fractional shortening of 15.8% ± 4.02% (95% confidence interval, 12% to 20%); moderate mitral regurgitation was seen in all babies.
METHODS: All babies underwent operation as soon as the diagnosis was made. Four babies had direct reimplantation of left coronary artery into the aorta, and 1 had tunnel repair. Intraaortic balloon counterpulsation was used in 1 baby for hemodynamic instability and as prophylaxis in the remaining 4 babies postoperatively for 115 ± 26.2 hours (95% confidence interval, 72 to 144 hours).
RESULTS: All babies had delayed closure of the chest. There was no operative mortality. One baby was reoperated on for tunnel stenosis as well as pulmonary stenosis 4 months after primary repair. All babies were followed for 192 patient-months and show an improved fractional shortening.
CONCLUSIONS: Early operation, early institution of intraaortic balloon counter pulsation for left ventricular support, and delayed sternal closure are the key to good results.
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Introduction
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Patients with anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) who present in infancy represent a group that has severe ischemia. The resulting left ventricular (LV) dysfunction in infants is associated with high operative risk. The LV function may further deteriorate owing to the negative effects of cardiopulmonary bypass and cross-clamp times. However, with optimal intraoperative myocardial preservation and timely mechanical support, the early results can be improved and in the long term, the LV function as well as the LV dimensions not only improve but may actually reach normal values. In this report we describe our surgical strategy in patients with compromised LV function operated on in infancy.
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Material and methods
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The case records of 5 consecutive infants presenting to us since 1994 were retrospectively studied. Of these, 4 infants were females and 1 one was male. The patient characteristics and echocardiographic findings are shown in Table 1.
All infants presented with signs of LV failure. Three had evidence of ischemia with LV strain on the electrocardiograph, whereas 2 patients had changes of anterolateral infarction. One patient required dobut-amine infusion for hemodynamic instability preoperatively. None of the patients required preoperative ventilation. Diagnosis was made on the basis of echocardiography on all the patients by demonstrating a dilated right coronary artery with retrograde flow through the left coronary artery into the main pulmonary artery. All patients showed a grossly dilated LV with poor function as assessed by fractional shortening (FS) measured in the parasternal short-axis view from M-mode echocardiography. Moderate mitral regurgitation was seen in all 5 babies. One baby also showed calcified papillary muscles, and 4 of them showed increased echogenicity of the mitral papillary muscles. Only 1 baby had preoperative cardiac catheterization. Operation was performed as soon as the diagnosis was made in all patients. All patients were followed up postoperatively with serial echocardiograms to assess improvement in FS and LV dimensions.
Surgical technique
Operation was performed through a median sternotomy on cardiopulmonary bypass using bicaval and single aortic cannulation and moderate hypothermia. Myocardial protection was achieved by antegrade cardioplegia through the aortic root after cross-clamping the aorta. Both the branch pulmonary arteries were snared to ensure efficient delivery of cardioplegia. The first patient in this series underwent a Takeuchi repair [1], whereas the subsequent 4 had a direct reimplantation of the anomalous coronary artery into the aorta. This is our present technique of choice.
We never attempted to repair the mitral valve at the time of coronary relocation. The first patient in this series was easily weaned from cardiopulmonary bypass on a moderate amount of inotropic support but 36 hours later had a dramatic deterioration with severe low cardiac output not responding to high doses of inotropic support including epinephrine. Echocardiogram done on the intensive care unit at that stage showed an FS of 20%, which was same as the preoperative value, a poorly contracting right ventricle, and a persistent moderate mitral regurgitation. There was no evidence of pulmonary stenosis or stenosis of the intrapulmonary tunnel. In the absence of any surgically correctable cause for refractory low output, an intraaortic balloon pump (IABP) catheter was introduced in the intensive care unit through the ascending aorta. This was followed by a dramatic improvement of the hemodynamic and clinical condition. The infant was taken off the balloon pump on the fourth day after insertion; however, the child was maintained on a ventilator for a further 6 days until her anticonvulsant treatment was optimized.
The choice of IABP was based on the fact that this is the only available form of mechanical assistance in our institution. Lack of left ventricular assist device or extracorporeal membrane oxygenation facilities in the institute compels us to maintain patients with more severe forms of ventricular dysfunction on prolonged cardiopulmonary bypass for supporting the heart [2].
On the basis of our first experience we changed our policy and prospectively decided to introduce IABP electively at the time of weaning the patients from cardiopulmonary bypass. Our hypothesis was that ischemic hearts with poor function preoperatively usually need the LV to be supported after correction [3]. Another goal was to reduce to the need for inotropic support after operation because inotropic agents have a potential to increase oxygen consumption and possibly jeopardize myocardial recovery.
As a consequence the remaining 4 patients had intraoperative institution of the IABP. Ideally we aimed at maintaining good hemodynamics with a left atrial pressure of no more than 10 mm Hg and to avoid use of epinephrine (the maximum dose of dobutamine we would use before introducing epinephrine is 15 µg/kg).
Technique of insertion of balloon catheter and its care
The balloon catheter was inserted antegradely through the ascending aorta using either the pursestring used for aortic cannulation or a separate pursestring when the IABP was started before weaning the patient from cardiopulmonary bypass. The appropriately sized balloon catheter was chosen based on age and weight guidelines recommended by Datascope (Datascope Corporation guidelines for pediatric balloon sizing, Fairfield, NJ, 1985) as described in Appendix 1. The length of the balloon catheter was premeasured on the child, and the estimated length was marked with a ligature. This was normally about 2 cm proximal to the origin of the balloon itself. The pursestring was secured by means of a plastic snugger that was fixed with multiple metal clips. This allowed the plastic snugger to lie in the chest with ease once the skin was approximated with a silicone elastomer membrane. It is our unit policy to keep the chest open in patients who have severely impaired cardiac function after operation. Accordingly, all patients had their sternum stented, and the skin was approximated using a silicone elastomer membrane. The balloon catheter exited the mediastinum from beneath the silicone elastomer membrane and was fixed to the skin before being attached to the pumping console. Particular attention was paid to make sure that no tension was applied to the balloon catheter. A chest roentgenogram was taken to ascertain the position of the balloon.
The balloon catheter was then attached to the Datascope System 97 pumping console (Datascope Medical Co Ltd, Cambridge, UK), which has a pediatric volume-limiting chamber. Helium gas is used for inflation of the balloon because of its brisk pneumatic response to increased heart rates that are normally seen in children. The balloon is manually filled every hour unlike the adult device, which runs on an automatic filling system. All patients were maintained on heparin infusion while the balloon pump was inserted, and the dose was adjusted to maintain the activated partial thromboplastin time 1.5 to 2.5 times normal value.
Monitoring
In addition to the routine hemodynamic variables, all patients also had left atrial pressure monitored postoperatively. Improvement in cardiac performance was inferred directly by means of serial echocardiograms and the suprasystolic augmentation seen on the arterial pressure waveform. Urine output, peripheral minus core temperature gradient, serial blood gas analysis, and serum lactate levels were used to determine the adequacy of end-organ perfusion, which in turn also indirectly indicated the adequacy of cardiac output. The aim was to keep the heart supported on IABP until satisfactory hemodynamics were obtained with inotropic support of enoximone or dobutamine infusion of 5 µg · kg-1 · min-1. Once hemodynamic stability was maintained, weaning was started on the basis of the factors listed in Appendix 2.
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Results
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There was no operative mortality. The IABP was used for a mean duration of 115.2 ± 26.2 hours (95% confidence interval [CI], 74 to 144 hours). There were no complications related to the insertion of the IABP. It was possible to bring down the enoximone or dobutamine infusion to 5 µg · kg-1 · min-1 soon after the insertion of the balloon in all the patients. In none of the patients was it necessary to prematurely remove the balloon catheter. The chest was kept open for a mean duration of 7.2 ± 1.3 days (95% CI, 5.9 to 8.3 days). None of the babies had any sternal wound infection. The median stay in the intensive care unit was 12 days (range, 12 to 66 days). All patients were followed up for a total of 192 patient-months. There was no late mortality. None of the patients show any signs of LV failure at follow-up. One child with moderate mitral regurgitation has been started on regular angiotensin-converting enzyme inhibitors.
The baby who underwent tunnel repair of ALCAPA had supravalvar pulmonary stenosis as well as tunnel stenosis. This child showed evidence of pulmonary stenosis on the echocardiogram performed on the 81st day after the initial operation. This infant had to be reoperated on for relief of tunnel stenosis as well as supravalvular pulmonary stenosis 4 months after the initial operation. This child at present has persistent mild pulmonary stenosis with a transpulmonary gradient of 30 mm of Hg. Follow-up electrocardiogram on all babies showed gradual resolution of ischemic changes. However, there was a persistence of pathologic Q waves and subnormal R-S progression as evidence of previous infarction in 2 patients. However, the FS has returned to normal not only in the patients who had ischemia alone, but also those who had infarcted. The average duration for the FS to return to normal was 18.4 weeks (range, 4 to 40 weeks; Fig 1).
All babies showed a progressive decrease in LV size. The LV diastolic dimension decreased from a preoperative value of 39.4 ± 8.06 mm (95% CI, 31.6 to 47.2 mm) to a postoperative value of 21.1 ± 6.7 mm (95% CI, 14 to 27.6 mm; Fig 2).
Similarly, the LV systolic dimension decreased from a preoperative value of 32.2 ± 8.9 mm (95% CI, 23.5 to 40.9 mm) to a postoperative value of 14.2 ± 5.0 mm (95% CI, 9.3 to 19.1 mm; Fig 3).
The time for the LV dimensions to decrease from the preoperative value to the normal range was very variable and ranged between 4 and 40 weeks. Mitral regurgitation has remained moderate in 1 patient and has regressed to mild in the remaining 4 babies. Color Doppler echocardiograms conducted on all infants and angiogram performed on 1 patient at follow-up showed the implanted left coronary artery to be patent in all.
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Fig 1. Improvement in fractional shortening (FS) postoperatively. Light bars = preoperative; dark bars = postoperative.
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Fig 2. Decrease in left ventricular end-diastolic dimension (LVDd) postoperatively. Solid bars = postoperative; open bars = preoperative.
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Fig 3. Decrease in left ventricular end-systolic dimensions (LVDs) postoperatively. Solid bars = postoperative; open bars = preoperative.
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Postoperative complications
One child had severe chronic lung disease preoperatively with multiple congenital bullae, and postoperatively required high-flow oscillation ventilation for poor carbon dioxide elimination. This child maintained an average partial pressure of carbon dioxide of 95 to 96 mm Hg on conventional ventilation. This child also had repeated loculated pneumothoraces requiring reexploration seven times for insertion and appropriate placement of intercostal drains and maintaining lung expansion. One baby was reexplored for bleeding, but this was not related to the IABP insertion site. There was one reoperation for tunnel stenosis and supravalvar pulmonary stenosis in the same baby. There was one incidence of right upper lobe collapse. One baby experienced a clot in the LV while on the ward, and required formal anticoagulation with heparin. There was also one episode of refractory arrhythmia requiring amiodarone infusion for 2 days immediately postoperatively.
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Comment
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In infants suffering from ALCAPA who had a compromised LV function, age at operation was not a risk factor for mortality as was previously thought [4, 5]. Anatomic studies conducted on hearts from babies who died of LV dysfunction secondary to ALCAPA have shown histologic features of chronic ischemia of varying degree. However, the severity of these ischemic changes had no relationship to age at death [6]. With these facts in mind, 5 infants with ALCAPA and compromised LV function were operated on in our institution as soon as the diagnosis was made. A dual coronary supply was established in all the patients, the Takeuchi technique was used in the first patient, but from the second patient onward we used the direct coronary relocation as we believe it is a better technique. We have never considered the single coronary technique because some babies with ALCAPA are known to have right coronary artery stenosis and hypoplasia. This vessel cannot then be considered a reliable source of blood supply to the entire heart, and in any case there is sufficient evidence that the dual coronary repair offers more advantages [7].
All the babies survived the operation. Although age at operation is not a risk factor for adverse outcome, infants with ALCAPA are known to have cardiogenic shock postoperatively despite adequate myocardial revascularization [8, 9]. In the preoperative period the myocardial viability in these infants is essentially maintained by down-regulation of contractile function to match the decreased blood supply. Of all the congenital heart maladies, ALCAPA syndrome definitely falls into the category in which myocardial hibernation exists [10, 11]. Inotropic support in this situation no doubt improves the hemodynamics but can also increase myocardial energy expenditure and precipitate myocardial infarction [12]. This seems to be confirmed by our first case, in which we could easily wean the patient from cardiopulmonary bypass, but the clinical and hemodynamic condition deteriorated 36 hours later and at that stage there was no more response to inotropic support although the patient had a good and prompt response to IABP. Early institution of IABP was used to prevent this myocardial necrosis secondary to increasing doses of pharmacologic support. In addition to maintaining the inotropic agents within physiologic limits, IABP was also used to augment diastolic filling of the coronary arteries and unload the LV. This has been shown to improve coronary perfusion and eventually LV function in adult patients suffering from ischemic heart disease [13, 14]. Prophylactic introduction of IABP at operation was performed, giving due consideration to the fact that myocardial stunning undoubtedly occurs in ischemic hearts that are further exposed to episodes of transient ischemia imposed by a variety of clinical situations including open heart operation. Ventricular function in these situations does not show immediate improvement despite good blood flow. In situations of poor preoperative LV function (as seen in our patients with a mean FS of 15%), the added stress of stunning is very likely to precipitate cardiac failure. These hearts after surgical correction require LV support until the myocardium recovers and the stunning abates [15]. Inotropic agents beyond a certain dose increase the oxygen requirements and possibly jeopardize the myocardial recovery in addition to causing end-organ damage, and in a way may not provide the same kind of support that mechanical devices provide. For this reason we decided to prophylactically introduce the IABP at the time of operation.
The application of IABP in infants is supposed to be limited because of elasticity of the aorta and tachycardia normal for age. Keeping stringent control on the timing of augmentation, we have seen augmentation with heart rates up to 196 beats per minute [16]. Although left ventricular assist device is considered to be the chosen method of support for LV failure in infants, the incidence of bleeding-related complications is high [5]. In institutions in which this facility is unavailable, like ours, IABP seems to provide a useful alternative. We have not found any balloon-related complications in our 5 patients. Although there was no operative mortality, there have been significant complications as mentioned; however, none could be attributed to the use of the balloon catheter. Insertion of the balloon catheter through the ascending aorta and then channeling it into the descending aorta definitely avoids the limb ischemia as well as complications related to the occlusion of major branches of the abdominal aorta [17, 18].
Mitral valve repair was not considered in any of the patients. In 4 of the 5 babies, mitral regurgitation has improved. This could be a result of the decrease in annular size with reduction in LV dimensions as well as improved papillary muscle perfusion. The baby who presented with calcification of papillary muscle continues to have moderate mitral regurgitation. The LV dimensions show marked improvement on chest radiographs. Left ventricular function has completely recovered in all the babies (Fig 4).
Recovery was seen as early as the fourth postoperative day in 1 baby. This early recovery could be explained on the basis of hibernating myocardium and reversal of postoperative myocardial stunning. Recovery time for myocardial function was variable. The late recovery may be a manifestation of reversal of down-regulation of contractile function that was secondary to reduced perfusion [12].
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Fig 4. (A) Preoperative poor left ventricular function and left ventricular dilatation seen on M-mode echocardiogram. (B) Postoperative improvement in left ventricular function and decrease in left ventricular dimension seen on M-mode echocardiogram.
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The prophylactic use of IABP could be considered a very aggressive attitude, and on the basis of the limited number of patients as well as the lack of evidence of what could have happened without the use of IABP, it would be very difficult to argue the contrary. However, although our experience is limited, it is remarkable that since the introduction of prophylactic use of IABP all our patients had stable hemodynamics with only a moderate need for inotropic support. It is also interesting that the IABP has been sufficient to support the LV in all the patients, and we did not need more aggressive forms of support such as left ventricular assist device or extracorporeal membrane oxygenation.
Infants with ALCAPA and poor LV function can be operated on safely as soon as the diagnosis has been made. Left ventricular function improves and reaches normal levels within a year after operation. The LV dimensions have consistently decreased during the follow-up period.
Intraaortic balloon counter pulsation is a useful way of supporting the heart in infants and helps recovery from immediate postoperative stunning in this group of patients. The timing of institution of mechanical support is vital, and we recommend the institution of IABP intraoperatively in all patients with poor preoperative LV function in whom the need of some form of assistance or high doses of inotropic support can be expected in the postoperative period.
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Acknowledgments
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The authors thank Tracy Oakes for her secretarial assistance.
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Appendix 1. Pediatric Intraaortic Balloon Specifications
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Age (y)
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Weight (kg)
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IABP Volume (mL)
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Catheter Size (Fr)
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IABP Length (cm)
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IABP Diameter (mm)
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IABP Preload (mL)
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| <1 |
3–8 |
2.5 |
4.5 |
10.7 |
6 |
6 |
| 1.1–2.5 |
9–13 |
5 |
5.5 |
12.8 |
8 |
10 |
| 2.6–5 |
14–18 |
7 |
5.5 |
14.2 |
9 |
12 |
| 6–12 |
8–10 |
12 |
7 |
17.8 |
10 |
17 |
>12
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>40
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20
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7
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19.4
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12
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26
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IABP = intraaortic balloon pump.
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Appendix 2. Intraaortic Balloon Pump Weaning Criteria
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Criteria
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| CVP < 10 mm Hg |
| LAP < 10 mm Hg |
| BP normal for age |
| Urine output > 1 mL/kg per hour |
| Temperature: peripheral to core difference < 2°C |
| Inotropic support < 5 µg/kg per minute |
No acidosis
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BP = blood pressure; CVP = central venous pressure; LAP = left atrial pressure.
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References
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- Takeuchi S., Imamura M., Katsumoto K., et al. New surgical method for repair of anomalous origin of left coronary artery arising from pulmonary artery. J Thorac Cardiovasc Surg 1979;78:7-11.[Abstract]
- Hadoma T., Takasaki H., Mori Y., et al. Clinical experience of veno-arterial bypass as a cardiac assist system using centrifugal pump with membrane oxygenator in patients with profound ventricular failure after cardiac surgery. Nippon Geka Gakkai 1993;93:1153-1158.
- Schmid C., Wilhelm M., Reimann A., et al. Use of an intraaortic balloon pump in patients with impaired left ventricular function. Scand Cardiovasc J 1999;33:194-198.[Medline]
- Vouhe P.R., Baillot-Vernant F., Trinquet F., et al. Anomalous left coronary artery from the pulmonary artery in infants. Which operation? When?. J Thorac Cardiovasc Surg 1987;94:192-199.[Abstract]
- Schwartz M.L., Jonas R.A., Colan S.D. Anomalous origin of left coronary artery from pulmonary artery: recovery of dual left ventricular function after dual coronary repair. J Am Coll Cardiol 1997;30:547-553.[Abstract]
- Smith A., Arnold R., Anderson R.H., et al. Anomalous origin of the left coronary artery from the pulmonary trunk. J Thorac Cardiovasc Surg 1989;98:16-24.[Abstract]
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- Shivalkar B., Borgers M., Daenan W. ALCAPA syndrome: an example of chronic myocardial hypoperfusion?. J Am Coll Cardiol 1994;23:772-778.[Abstract]
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Abstract
Introduction
