High Systolic reading

My Mother who is 85yrs old has poor circulation problems (It runs in the family).  She recently had her annual checkup at the cardiologist clinic and her systolic pressure was 240.  She will be seeing the specialist.  The nurse told her they werre not concerned with the Diolostic pressure .
What are the dangers of such high systolic pressure.  
Does it mean there are blockages?

[Cleveland Clinic, MD]

Dear Helene,
There are two components of blood pressure, systolic and diastolic.  These are the "top" and "bottom" numbers respectively.  Normal blood pressure is 120/80.  High blood pressure is considered 140/90 or greater.  A systolic of 240 would be considered very high.  The main risk of acutely high blood pressure is stroke.  There is a greater risk of having blockages in the arteries with high blood pressure but blockages do not cause hypertension.