I have done no further research than wikipedia, but as far as I can see the risk is acute—once the compound is broken down the risk is gone. 

Basically, cocaine is bad for your heart. Mixing cocaine and alcohol produce a compound that is similar in effects to cocaine, longer lasting, and it’s worse for your heart than plain old cocaine. 

Technically, all that statistic says is that you’re 18-25x more likely to drop dead while doing cocaine if you’re drinking too. It doesn’t actually tell us anything about how bad it is for the heart, or if the danger is transient or cumulative. However, how many people just fall over dead in the bar bathroom doing bumps? Virtually none. 18-25x virtually zero is still virtually zero. 

I’ve done a ton of cocaine and a ton of cocaethylene so i’m totally an expert on this. 

edit: I’d be closer to an expert if that paper wasn’t behind a paywall and I weren’t too lazy to look elsewhere.