Which ailments of the circulatory system are most common?

Here is the list. High blood pressure(hypertension) atherosclerosis(hardening of the arteries). This can lead to heart attack(coronary artery occlusion), stroke or peripheral vascular disease(may cause gangrene from poor circulation in the legs). Vascular occlusions can also occur due to blood clots inside the diseased arteries and or inside the veins(venous thrombosis which can lead to pulmonary embolism( lungs).