If the primary purpose of the annual visit is to address the status and management of the patient's chronic conditions, such that these are the primary diagnoses on the claim form, you should use the usual office visit codes (assuming the services are provided in the office).
When the blood vessels are this small they are called capillaries. There are more capillaries (and more miles of capillaries) than any other kind of blood vessel. To answer your question, there are approximately 60,000 miles of blood vessels in an adult human body. That's about 100,000 kilometers. And if you really did stretch out your vessels for 60,000 miles most of them would be capillary miles. Each capillary is very short, but there are so very many of them. I found the answer to your question in a college textbook of human anatomy and physiology.
On average how big is the heart? How long is the system of blood vessels? How many quarts does the adult heart pump each minute? How many times does the heart beat a day; How many times does the heart beat in an average human life? How much does an adult woman's heart weigh; How much does an adult man's heart weigh; What percentage of the blood is water