Surgical correction of ALCAPA is highly recommended, regardless of age or the degree of intercoronary collateralization. This protocol presents a technique for the direct re-implantation of adult-type ALCAPA into the aorta to re-establish the dual-coronary perfusion. Whenever feasible, direct re-implantation is preferred to other surgical correction techniques.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly which is one of leading causes of myocardial ischemia and infarction in children. If left untreated, it results in a 90% mortality rate in the first year of life. In patients who survive to the adulthood, the coronary steal phenomenon and retrograde left-sided coronary flow provide a substrate for chronic subendocardial ischemia, which may lead to left ventricular dysfunction, ischemic mitral regurgitation, malignant ventricular arrhythmias, and sudden cardiac death. The average age of life-threatening presentation is 33 years and of sudden cardiac death 31 years. Therefore, surgical correction is highly recommended as soon as the diagnosis is made, regardless of age. In adult-type ALCAPA originating from the right-facing sinus of the pulmonary artery, direct re-implantation of the ALCAPA into the aorta is the more physiologically sound repair technique to re-establish the dual-coronary perfusion system and is recommended. This protocol describes the technique of direct re-implantation of adult-type ALCAPA into the aorta.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly usually seen as an isolated lesion1. The incidence of ALCAPA is estimated at 1 in 300,000 live births, comprising between 0.24% and 0.46% of congenital cardiac diseases2,3. It is one of the most common causes of myocardial ischemia and infarction in children and, if left untreated, results in a 90% mortality rate in the first year of life4. Only 10 – 15% of infants survive to adulthood due to the rapid development of a large dominant right coronary artery (RCA) with extensive intercoronary collaterals4. During the neonatal period, high pulmonary vascular resistance and the resultant pulmonary artery (PA) pressures ensure that antegrade flow is maintained from the PA into the anomalous left coronary artery. As the pulmonary vascular resistance gradually decreases, antegrade flow to the left coronary artery reduces. This eventually leads to reversal of flow, and left-to-right shunting into the PA, thus resulting in a "coronary steal5." Thus, left ventricular (LV) myocardial perfusion depends on intercoronary collaterals from an RCA5,6.
The coronary steal phenomenon and retrograde left-sided coronary flow provide a substrate for chronic subendocardial ischemia, which may lead to left ventricular dysfunction, ischemic mitral regurgitation, and malignant ventricular arrhythmias precipitated by acute myocardial ischemia7. In a subset of adult patients, the mean age at presentation is 41 years, with a shift in sex distribution toward female patients (Female-to-male ratio: 2:1)8. In this patient population, 14% are asymptomatic; 66% present with symptoms of angina, dyspnea, palpitations, or fatigue; and 17% present with life-threatening symptoms, including ventricular arrhythmias, syncope, and sudden cardiac death8. The average age of life-threatening presentation is 33 years and of sudden cardiac death 31 years8. Therefore, surgical correction is highly recommended as soon as the diagnosis is made, regardless of age or the degree of intercoronary collateralization1,9.
Depending on the origin of the anomalous left coronary artery, direct re-implantation of the ALCAPA into the aorta is the more physiologically sound repair technique to reestablish the dual-coronary perfusion system. Most commonly, ALCAPA takes off from the right-hand pulmonary sinus (sinus 1 of the PA), which faces the aortic sinus where the main left coronary artery usually originates (sinus 2 of the aorta)10. This coronary anatomy is most suited to the direct re-implantation technique. The aim of this report is to describe, in detail, the technique for the direct re-implantation of the left coronary artery in ALCAPA in adult patients. The rationale behind direct re-implantation is the advantage-the physiological reestablishment of dual-coronary perfusion-it offers over the ligation of the anomalous left coronary combined with coronary artery bypass grafting11,12,13.
The protocol follows the institutional guidelines of the human research ethics committee of the University of Zurich.
1. Preparation for Surgery
2. Surgery
Presentation
The patient was a 48-year-old woman presenting with the recent onset of angina Canadian Cardiovascular Society (CCS) grad III and occasional palpitations. She reported three uneventful pregnancies. Moderate smoking was the main cardiovascular risk factor. Trans-thoracic echocardiography showed a moderately impaired (45%) left ventricular ejection fraction and no mitral regurgitation. A coronary angiography was then performed. It demonstrated the absence of the left main coronary artery arising from the aorta. The right coronary artery was considerably enlarged and perfused the main left coronary artery via intraseptal collaterals (Figure 1). Thus, the diagnosis of ALCAPA was made. The anatomical type of ALCAPA was further defined by bi-plan (Figure 2) and three-dimensional (Figure 3) CT scans.
Post-operative Course
The patient was separated from the cardiopulmonary bypass at a core temperature of 37 °C. No post-operative myocardial ischemia occurred. Bleeding from the chest tube drain was less than 30 mL/h. The patient was weaned from the ventilator and extubated 6 h post-operatively. She was discharged from the intensive care unit to the normal ward on the first post-operative day. Her course on the ward remained uneventful; she was discharged to a cardiac rehabilitation program on post-operative day 9.
One-year Follow-up
The patient was seen at the outpatient clinic one year after surgery. She was working full-time and had no angina or dyspnea. Her exercise test was negative. Figure 4 shows her CT scan one year after surgery. The re-implanted ALCAPA is widely patent at the site of anastomosis to the aorta. The pulmonary artery does not present any narrowing at the site of reconstruction with the autologous pericardial patch used to repair the defect in the right-facing sinus of the PA.
Figure 1: Pre-operative Coronary Angiography. A) The coronary angiography of the patient is remarkable for the absence of the ostium of the main left coronary artery (LCA) in the aorta. In a right anterior oblique view, the opacified right coronary artery (RCA) is considerably enlarged, measuring 12 mm. It follows a tortuous path across the right heart while supplying large collaterals to the left-sided circulation via intraseptal collateral vessels (yellow arrows). These collaterals feed the left anterior descending (LAD) and left circumflex (CX) arteries, which join the main left coronary artery and drain in a retrograde fashion into the main pulmonary artery (PA). B) This diagram shows a schematic representation of the normal distribution of the coronary arteries. (1 mm on figure scale = 2 mm) Please click here to view a larger version of this figure.
Figure 2: Pre-operative Computed Tomography. A cardiac computed tomography scan shows the take-off of the ALCAPA from the right-facing sinus of the PA according to the Dodge-Khatami classification10. (1 mm on figure scale = 2.14 mm)
Figure 3: Pre-operative Three-dimensional Computed Tomography. A three-dimensional reconstruction of the computed tomography of the great vessels confirms the topography of the ALCAPA originating from the right-facing sinus 1 of the PA and the RCA from the facing sinus 1 of the aorta10. From this anatomy, a direct translocation of the ALCAPA to the aorta seems feasible. (1 mm on figure scale = 1.66 mm) Please click here to view a larger version of this figure.
Figure 4: Follow-up Post-operative Computed Tomography. In the right panel, the computed tomography scan of the patient one year after surgery shows a widely patent main left coronary artery (ALCAPA) connected to the aorta. The reconstructed pulmonary artery (PA) does not present any narrowing. In the left panel, the pre-operative computed tomography depicts the ALCAPA originating from the right-facing sinus of the PA according to the Dodge-Khatami classification10. (1 mm on figure scale = 2.14 mm in the left panel, 1 mm on figure scale = 2.5 mm in the right panel) Please click here to view a larger version of this figure.
This protocol describes a detailed technique for the direct re-implantation of the ALCAPA into the aorta in an adult patient with the origin of main left coronary artery from the right-facing sinus of the pulmonary artery according to the Dodge-Khatami classification10. The myocardial protection strategy and the reconstruction of the pulmonary artery are clearly demonstrated. The major critical step of this technique is represented by the generous mobilization of the left coronary artery to achieve a tension-free anastomosis.
Prolonged desaturated coronary perfusion is tolerated into adulthood in a small number of individuals. ALCAPA patients who survive to adulthood present with a spectrum of clinical manifestations, ranging from the absence of symptoms to acute myocardial infarction and/or chronic myocardial ischemia8. The latter would ultimately lead to left ventricular dysfunction, ischemic mitral regurgitation, malignant ventricular arrhythmias, and sudden cardiac death7. Therefore, surgical correction is highly recommended as soon as the diagnosis is made, regardless of age or the degree of intercoronary collateralization1,9.
In both adults and infants, the direct re-implantation of the ALCAPA represents the physiological repair method and is the preferred technique when the anatomy is suitable1. However, in adults, the direct re-implantation of the ALCAPA might be more challenging because of a very short main left coronary artery, increased coronary artery friability, diminished vessel elasticity for mobilization, and the potential for tearing and the resultant uncontrollable bleeding14,15. In these situations, coronary artery bypass grafting associated with the ligation of the ALCAPA may be more suitable11,12,13. In a series of 30 patients with ALCAPA, 3 of which were adults, Neumann et al. performed 19 direct re-implantations, 9 Takeuchi repairs, and 2 ligations16. The early and late 24-year survival rates for direct re-implantation were both 100%, and the 10-year rate of freedom from reoperation was 94.1%16. At the last follow-up, 95.5% of the patients were in New York Heart Association functional class I16.
Other options for surgical repair aim to prevent the coronary steal phenomenon and, ideally, to restore dual-coronary circulation. The simplest corrective procedure involves ligating the LMCA, which does prevent steal, but does not allow for antegrade flow into the left-sided circulation. Therefore, this is most often combined with bypass grafting11,12. This approach, less physiological than the previous, is generally the most straightforward in adults, but there remains a risk of late graft stenosis, especially with saphenous vein grafts13. In adults, creating an intrapulmonary baffle (Takeuchi procedure) is a more complex option that does restore the dual-coronary supply but that may be complicated by supravalvular pulmonary stenosis and baffle obstruction or leakage13,17.
The treatment of associated ischemic mitral valve regurgitation remains controversial and depends on the degree, as well as the functional versus structural type, of regurgitation. The age of the patient, the personal experience of the surgeon, and the ability of the center must also be considered. In infants, most authors recommend an expectative approach, unless the mitral regurgitation is severe1,16. In adults, the decision on the concomitant surgical correction of functional ischemic mitral regurgitation during the operation for ALCAPA should be made with regard to the severity of the mitral regurgitation and the possibility for it to worsen after intra-operative norepinephrine tests. An aggravation of mitral regurgitation following norepinephrine challenge, evidenced by intra-operative transesophageal echocardiography, would support the correction of the mitral regurgitation. For structural mitral regurgitation, correction would be recommended for more than mild regurgitation, unless the prolongation of the cross-clamp time is deemed undesirable for the patient.
In conclusion, in adult-type ALCAPA originating from the right-facing sinus of the pulmonary artery, direct re-implantation into the aorta is recommended, provided that the tissue is of adequate elastic quality. Thickening and calcification of the main left coronary could be detected in the pre-operative computed tomography. However, the final evaluation of the tissue elasticity is performed by intra-operative visual inspection and gentle palpation of the vessel wall for the absence of calcified plaques and by the tactile perception of tissue resistance during mobilization.
The authors have nothing to disclose.
This work was supported by a grant of the Swiss Cardiovascular Foundation to RT.
Heart surgery infrastructure: | ||
Heart Lung Machine | Stockert | SIII |
EOPA 24Fr. arterial cannula | Medtronic | 77624 |
Quickdraw 25Fr. femoral venous cannula | Edwards | QD25 |
LV vent catheter 17Fr. | Edwards | E061 |
Antegrade 9Fr. cardioplegia cannula | Edwards | AR012V |
Retrograde 14Fr. cardioplegia cannula | Edwards | NPC014 |
Electrocautery | Covidien | Force FX |
Name | Company | Catalog number |
Sutures: | ||
Polypropylene 4/0 | Ethicon | 8871H |
Polypropylene 5/0 | Ethicon | 8870H |
Polypropylene 6/0 | Ethicon | EH7400H |
Braided polyesther 2/0 ligature with polybutylate coating | Ethicon | X305H |
Intergard dacron graft 8 mm | Maquet | IGW0008-30 |
Micro knife Sharpoint | TYCO Healthcare PTY | 78-6900 |
Name | Company | Catalog number |
Drugs: | ||
Midazolam | Roche Pharma | N05CD08 |
Rocuronium | MSD Merck Sharp & Dohme | M03AC09 |
Propofol | Fresenius Kabi | N01AX10 |
Fentanil | Actavis | N01AH01 |
Name | Company | Catalog number |
Instruments: | ||
Cooley Derra anastomosis clamp | Delacroix-Chevalier | DC40810-16 |
Cooley vascular clamp | Delacroix-Chevalier | DC40810-16 |
Dissection forceps Carpentier | Delacroix-Chevalier | DC13110-28 |
Scissors Metzenbaum | Delacroix-Chevalier | B351751 |
Needle holder Ryder | Delacroix-Chevalier | DC51130-20 |
Dissection forceps DeBakey | Delacroix-Chevalier | DC12000-21 |
Micro needle holder Jacobson | Delacroix-Chevalier | DC50002-21 |
Micro scisors Jacobson | Delacroix-Chevalier | DC20057-21 |
Lung retractor | Delacroix-Chevalier | B803990 |
Allis clamp | Delacroix-Chevalier | DC45907-25 |
O’Shaugnessy Dissector | Delacroix-Chevalier | B60650 |
Vessel loop | Medline | VLMINY |
18 blade knife | Delacroix-Chevalier | B130180 |
Leriche haemostatic clamp | Delacroix-Chevalier | B86555 |