|Vascular system in humans and animals is divided into the blood circulatory system, which contains the heart and blood vessels for the circulation of the bloodline and lymphatic system, consisting of lymph glands and lymphatic vessels, through which a colorless fluid, the lymph, circulates. Angiology is the branch of medical science that studies the circulatory, lymphatic system, and vascular diseases.Medical specialty which studies circulatory system, lymphatic system and their disease is called angiology. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.