Dear Dr Chai,
This is - first - to thank you for the extended and comprehensible report of your clinical review. I am very comfortable with your conclusions and recommendations and will follow your guidance. It also gives me the opportunities to say to you how impressed I have been with your department over the last 3 years when I have been a not-quite-straightforward patient.
All of the staff I have met have been notable for their professionalism and also for their high level of communication skills and willingness to explain. This last task - explanation - can be tedious and difficult with some patients, but it does make a surprisingly large contribution to their mental if not their physical welfare.
Thank you and best regards,