High Blood Pressure

[missiokie]

My husband last year had 2 stress heart attacks after Hurricane Dean destroyed our home here in Mexico. The doctor put him on bp medicine and changed it end of May to Micardis plus and Dilatrend. All has been well until last Friday when his blood pressure was high on the bottom number and medium on the top. All day for 4 readings it was 156/110-117, then the next day was better, Sunday better and yesterday. Today it is back to 117/85. My question is when is it dangerously high to seek medical attention? What could be the cause of the spike on the bottom, and what does the bottom high mean?

Thank you for your assistance.