While the traditional teaching ramains as systolic blood pressure would be determined by cardiac contractility / cardiac out put , while the diastolic pressure is determined by peripheral vascular resistance .This is not an absolute reality , rather it is too simplistic way of teaching circulatory physiology !
The peak systolic blood pressure is more often determined by the integrity of Aortic and major arteries rather than cardiac contractility and stroke volume. Similarly , aortic properties do have a say in the diastolic pressure as well !
Further reading and debate
The net effect of aging on blood pressure : Is it physiological or pathological ?
Should we treat this raised pressure due to aging related systolic hypertension ?
There is a huge controversy going around , regarding the need of treating this mild elevation of systolic blood pressure due to arterial stiffening .This will be addressed separately in this forum .