ALB and myalgic encephalomeyelitis/chronic fatigue syndrome: Pre-PCI frail (CFS ≥ 5) was the significant factor associated with the MACE after adjustment for variables including age, sex, DM, LVEF < 40%, LMCA or multivessel disease, and serum albumin < 3.5 g/dL (HR 4.27, 95%CI 1.86–9.80, p-value: < 0.001).