Ricardo Wang et al. Estevão Lanna Figueiredo Fernando Carvalho Neuschwander
Total coronary occlusion (TCO) is characterized by an obstruction with an estimated duration of more than 3 months and is present in approximately 15–18% of all coronary angiographies performed. Clinical manifestations can range from asymptomatic, through stable angina, to varying degrees of ventricular dysfunction. This mainly depends on the degree of collateral circulation. If it is poor, it may compromise the viability of myocytes and associate with various degrees of necrosis and/or hibernating myocardium. In the presence of well-developed collaterals (Rentrop grade III), the patient may be asymptomatic and have a preserved contractile function. Therefore, the formation of a well-developed collateral circulation, especially before vessel occlusion, is essential for the preservation of myocytes.
Despite advances in the clinical treatment of stable angina, many patients with TCO undergo interventional procedures. Of these, most are referred for coronary artery bypass grafting surgery or percutaneous coronary intervention (PCI) with more advanced techniques, but also with a higher risk of complications. The study of mechanisms potentially stimulating arteriogenesis and angiogenesis (collateral circulation formation) opens up opportunities for the development of drugs that, in turn, would avoid unnecessary interventions and/or could benefit patients with symptoms refractory to optimized conventional clinical treatment and who are poor candidates for interventions (e.g., thin distal bed, diffuse coronary disease).
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