Y-graft and proximal LIMA flow adaptability: the surgical wisdom of iatrogenics

Abstract

Through their recent article, Lemma et al. [1] reported gratifying adaptability to the flow of proximal LIMA when using Y-graft revascularisation, corroborating previous investigation in this field [2], and on which the authors should be congratulated. Although the authors concluded that the distal flow of LIMA is similar between Y-graft and single graft groups, exclusive Ygraft revascularisation may raise concerns over attendant physiological disturbances afflicted to the integrated perfusion of coronary systems and their interplay. Apart from successfully measuring the relative flow and demonstrating technical feasibility, the exclusive Tor Y-graft nonetheless results in a perfusion pattern similar to a left-dominant coronary system. It is well documented that the systolic antegrade flow of LAD is composed by antegrade flow from left Valsalva sinus and systolic retrograde given way by its collaterals such as septal and diagonal arteries [3]. Although being slighted in routine practice, the functional role of the latter is crucial. When occluding LAD with balloon, the amount of systolic recruitable collateral flow in LAD increases proportional to increasing flow in contralateral artery [4]. Such a collateral flow that is dependant on myocardium contractility [5], myocardial collateral pump, gives horizon to new integrated insights in coronary physiology, consequences of which should be taken surgically in good advantage. Therefore, LAD can be seen as having two potential inflows, double-LAD inflow, the importance of which is obvious in clinical practice, such as in the setting of occluded LAD and myocardial hypertrophy where the amount of systolic recruitable flow is increased. Similarly, the loss of contractility by septal infarction that blunt myocardial