Asymptomatic friend may be infected

Dear Dr. Roach: I am scheduled to play tennis with my friend tonight. His son tested positive for COVID-19 and is symptomatic as of yesterday. He has not seen his son for at least one week before the diagnosis. Is my friend safe, and would it therefore be safe for me to play tennis with him? He seems to think he would have needed to see him three to five days before diagnosis/symptoms to be at risk. What say you?

J.G.

Answer: It is not safe to play tennis with your friend. A person with COVID is potentially infectious for 10 days. Had your friend and his son been exposed at the same time, your friend could be infectious now with an asymptomatic case. It’s also possible that your friend got exposed by his son. Symptoms normally begin within six days after exposure.

People seem to be most contagious in the early stages. Still, you cannot be sure your friend is not contagious. For that reason, waiting two weeks from the time of exposure is best.

Dear Dr. Roach: I am 74 with Type 2 diabetes. Recent cardiac studies including a cardiac catheterization revealed a few blockages in my coronary arteries, and I was advised to undergo bypass grafting. I understand arterial grafts are better than venous grafts because they last longer. If this is true, do I have a choice as patient?

R.

Answer: A “bypass” means that the blocked area of the artery is bypassed by placing a new blood vessel after the area of blockage, just like a traffic jam can be bypassed by going on a side road. Using a thick blood vessel — artery, especially the left internal mammary artery — does give better results than a thin blood vessel like a vein, often taken from the leg.

The cardiac surgeon will use an artery whenever it is technically possible to do so.

If I were getting the surgery, I might ask whether the surgeon thinks it possible to use the left internal mammary artery, but I would rest comfortably knowing my surgeon uses his or her expertise to make the best decision for my case.