ALB and nutritional deficiency disease: Heart failure itself does not lead to hypoproteinemia, but patients with prolonged heart failure are often combined with infections, malnutrition, and other complications, which exacerbate the loss of albumin, and the reduction of albumin levels is closely related to inflammation, oxidative stress, endothelial dysfunction, and other pathologies, which can lead to circulating blood volume deficiency, disrupting fluid balance, and leading to heart failure decompensation.