Is a cvs a higher risk procedure than amniocentesis?

Yes, if. Depending on when the amnio is done; if done at 16-18 weeks, the amnio risk is somewhat lower (around 1/200.).
No. Amniocentesis is usually offered between 15-20 weeks, with a pregnancy loss rate of about 1 in 300-500. Chorionic villus sampling (cvs) is offered after 9 weeks. The pregnancy loss rate appears to be about the same as amniocentesis. There are additional fetal risks if it is performed before 7 weeks. The benefit of cvs is earlier detection, which allows for safer termination, if desired.