“Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation, usually measured at a person's upper arm. A person’s blood pressure is usually expressed in terms of the systolic (maximum) pressure over diastolic (minimum) pressure”– Wikipedia. This class represents the measurement (or “clinical observation”) of the patient’s Diastolic Blood Pressure, which is the minimum pressure exerted by circulating blood upon the walls of blood vessels during the heart’s pumping phase. This class also re-defines the generic clinical Observation class to fix the observed characteristic to LOINC 8462-4. "Diastolic blood pressure (in mmHg)." - PCORnet Common Data Model, Vital.Diastolic