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, and your friend would have to have an asymptomatic case to be contagious now. 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. Of course, if you live in an area of ongoing transmission, anyone who is not isolating themselves carefully might be exposed, and that means that you need to consider everyone as potentially contagious.
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 cardiac catheterization is a procedure where a small tube (catheter) is inserted into the arteries of the heart and dye is injected with an X-ray machine running to see whether there are blockages in the artery. This is also called a coronary artery angiogram. It’s the definitive test for blockages.
Far fewer bypass grafts are done now compared with 20 years ago. The medications we have for treatment are much better, and fewer people have clear indications that surgery is better than medication treatment. However, people with diabetes do better with surgery in many situations.
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. It is far beyond my expertise to go over all the factors a cardiac surgeon considers. 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.
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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.