Yes, the nurse was correct. the systolic pressure represents the pressure exerted on the vessles during contraction, and diastolic represents the exerted force inbetween contractions or while the heart is "at rest." so one could reason that the diastolic may be more "important", as it is a constant pressure.
Although both systolic and diastolic blood pressures tend to rise and fall together, especially in young and middle-aged adults, diastolic pressure fluctuates less. For this reason, doctors have traditionally focused on the diastolic reading. However, in 2003, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) published a new classification of blood pressure for adults that states unequivocally that in people over 50, a systolic reading of more than 140 mm Hg is a much more significant factor in cardiovascular disease than the diastolic reading. This was based on a preponderance of research evidence highlighting the significance of systolic pressure. For example, the Framingham Heart Study showed that systolic blood pressure alone correctly identified 91% of those who needed treatment, while high diastolic pressure identified only 22% of individuals needing treatment. In addition, the Systolic Hypertension in the Elderly Program, or SHEP, trial found that drug treatment for high systolic pressure significantly reduced the risk of stroke by 36% and cut heart attack and heart failure rate.
