The short answer is it depends.
The longer answer is… it depends.
The following is for educational purposes only. It is not meant to diagnose or treat any of your conditions. Please seek the advice of your own clinician.
For a great period of time simple plumbing mindset was applied to coronary circulation. It was felt that clearing the blockages would always result in better health for the patient.
Several years ago, a sham controlled randomized trial proved that stable coronary artery disease showed no improvement via stenting versus medical treatment.
Additionally, there’s been research that is shown that clearing a coronary artery obstruction when the body has already established collateral circulation also did not offer any significant improvement in outcomes.
Due to the CAD a patient will always be at some degree of risk. However, CAD is a fairly common diagnosis that I have no doubt hundreds, if not thousands, of people dive with daily. Some have already survived their first heart attack.
The existence of CAD does place a patient at higher risk than someone without, but that risk is all relative.
“After adjustment, 1-year MI rates increased with increasing CAD extent. Relative to patients with no apparent CAD, patients with 1-vessel nonobstructive CAD had a hazard ratio (HR) for 1-year MI of 2.0 (95% CI, 0.8–5.1); 2-vessel nonobstructive HR, 4.6 (95% CI, 2.0–10.5); 3-vessel nonobstructive HR, 4.5 (95% CI, 1.6–12.5); 1-vessel obstructive HR, 9.0 (95% CI, 4.2–19.0); 2-vessel obstructive HR, 16.5 (95% CI, 8.1–33.7); and 3-vessel or LM obstructive HR, 19.5 (95% CI, 9.9–38.2). One-year mortality rates were associated with increasing CAD extent, ranging from 1.38% among patients without apparent CAD to 4.30% with 3-vessel or LM obstructive CAD. After risk adjustment, there was no significant association between 1- or 2-vessel nonobstructive CAD and mortality, but there were significant associations with mortality for 3-vessel nonobstructive CAD (HR, 1.6; 95% CI, 1.1–2.5), 1-vessel obstructive CAD (HR, 1.9; 95% CI, 1.4–2.6), 2-vessel obstructive CAD (HR, 2.8; 95% CI, 2.1–3.7), and 3-vessel or LM obstructive CAD (HR, 3.4; 95% CI, 2.6–4.4). Similar associations were noted with the combined outcome.”
Little is known about cardiac adverse events among patients with nonobstructive coronary artery disease (CAD). To compare myocardial infarction (MI) and mortality rates between patients with nonobstructive CAD, obstructive CAD, and no apparent CAD ...
pmc.ncbi.nlm.nih.gov
So yes the risk is increased, but the baseline risk for any one person of having a heart attack over the course of a year is pretty damn low to begin with.
It’s also worth noting that study is about a decade old.
It’s also worth asking what harms will come from stopping diving. Depression, substance abuse, lack of exercise, isolation may all be far more risk than the baseline risk of ACS and the slight increase in that associated with diving. Doubly so when someone is fairly active with the CAD as a backdrop.
If a patient is comfortable with that risk, demonstrates they are able to be physically active without issues, are managed medically to the maximum tolerated/recommended, do not see why stable CAD alone should preclude someone from diving.
