The Cornucopia of “Pleiotropic” Actions of Statins

Abstract

See related article, pages 255–264 Initially described in patients with coronary artery disease undergoing coronary artery bypass graft (CABG) surgery, myocardial “hibernation” denotes a state of adaptive reduction in myocardial contractile function in response to limited energy supply caused by reduced blood flow.1,2 In this precarious equilibrium, the myocardium can remain viable for sustained periods of time (although not indefinitely) and slowly resumes contractile activity on restoration of perfusion.2,3 Hibernating myocardium resulting from a flow-limiting coronary artery stenosis is a common clinical entity that contributes to myocardial dysfunction in many patients with ischemic heart disease1,2; its clinical importance stems from the fact that is it is potentially reversible. The pathophysiological basis of this syndrome was proposed as a conceptual framework in 19924 and subsequently tested in various animal models5–8: it is likely to involve recurrent brief episodes of ischemia, which initially result in repetitive “stunning” with normal resting flow and eventually cause a persistent decrease in resting function and flow.2,4–6,8 Over time, these changes lead to myocyte loss resulting from degenerative changes and apoptosis.2,8 Because mechanical dysfunction is caused by a restriction in blood flow, revascularization has traditionally been the cornerstone of therapy for myocardial hibernation. Indeed, restoration of blood flow via CABG or percutaneous coronary interventions often improves the mechanical performance of hibernating myocardium.1–3,8,9 In those cases in which these procedures are not feasible, however, there is a need for alternative approaches. Direct transmyocardial laser revascularization10 and intramyocardial gene transfer of phVEGF16511 or fibroblast growth factor-57 have been reported to enhance perfusion and contractile reserve and improve regional function in experimental models of hibernation. Transplantation of circulating progenitor cells following revascularization has also been reported to attenuate hibernation (ie, to increase coronary flow reserve …