I Am 57 Years Old, Have Had Cardiac Artery Stenting

I am 57 years old, have had cardiac artery stenting done 4 years ago, am taking Bisoprolol fumarate 2.5 mg and Rosuvastatin 10 mg daily. I live in a tropical city ( Mumbai ) by the sea, and am leaving for the mountains tomorrow for a trek that takes me from 7000 feet to 12000 feet over 2 days. Temperatures are moderate there ( 5 - 20 degrees C min - max ). Please advise any precautions I need to take in view of the change in altitude