Edit, here's some starters:
ACE inhibitors: 5% (https://www.ncbi.nlm.nih.gov/pubmed/23750680)
Statins: no benefit (https://jamanetwork.com/journals/jamainternalmedicine/fullar...)
Aspirin: might actually be bad for you (https://www.nejm.org/doi/full/10.1056/NEJMoa1803955)
It may sound farfetched, but there's nothing in the OP that indicates the direction of causality to me, so it's possible that lower cardiovascular risk causes people to go out and get dogs, or that there's some root cause which causes people to both have lower cardiovascular risk and higher chance of owning a dog.