This exceptional case of a late presentation of ALCAPA was not only interesting from a clinical and imaging perspective but also from a therapeutic standpoint. Since patients with this anomaly rarely survive past infancy without surgical correction, very few adult patients have been reported in the literature, especially after 40 years old. We believe that patients can survive through adulthood with this anomaly without significant myocardial damage because of the development of an important collateral flow from the RCA.
Multiple procedures have been proposed in adults with ALCAPA including ligation of the left main coronary artery (LMCA), re-implantation of the LMCA to the aorta, creation of a baffle through the pulmonary artery (Takeuchi procedure) and a combination of LMCA ligation and CABG. Although re-implantation of the LMCA to the aorta remains the most physiological correction for this anomaly, the combination of LMCA ligation and CABG provides a dual coronary flow system and is preferable when re-implantation is impossible [2
In this case, re-implantation of the LMCA into the aorta was considered unfeasible because of the distance between the insertion site of the LMCA on the PA and the aorta. The Takeuchi procedure was also considered but discarded because of the reported increased risk of supra-valvular stenosis as the distance increases between the insertion site of the LMCA and the junction between the aorta and the pulmonary artery [4
]. End-to-end anastomosis of the LMCA with the aorta using an interposition arterial graft was not achieved because of the frailty of the surrounding tissues, the numerous collateral branches, and the inability to mobilize the bypassed vessel sufficiently to achieve an hemodynamically favorable end-to-end anastomosis. Creation of a tube graft using pulmonary artery wall autograft, as described by Wu et al. [5
], with a remote LMCA insertion site in regards to the aorta, could have been another valuable option.
The collateral flow in this patient was impressive. Following LMCA ligation on CPB, cardiac arrest was not attained despite adequate cool antegrade and retrograde cardioplegia flow and relative hypothermia. In order to match the size of the large LAD, allow unrestricted flow and avoid competitive flow between the graft and the collaterals from the RCA, the largest possible conduit was selected. The choice of a large SVG conduit over an arterial graft (such as the internal thoracic or the radial artery) was in response to this situation.
In a series of 6 adult patients who underwent saphenous vein bypass grafting and direct ALCAPA closure from inside the PA, Moodie and associates reported a graft patency rate of 80% at a mean follow-up of 5.8 years [6
]. Furthermore, 10-year patency of a SVG was found to be 88% when grafted to a large size LAD (larger than 2.0 mm), as reported by Goldman et al. [7
]. Moreover, we obtained a SVG flow of 117 ml/min as measured at the time of surgery, which is significantly higher than what we routinely measure in LITA pedicles grafted to the LAD. We believe that this high blood flow in the SVG, along with dual antiplatelet treatment (AAS and Clopidogrel) will result in excellent long-term patency.