Aetna is an insurance company and provides no health care. Unfortunately Aetna is trying to dictate and make decisions for doctors. Only lawsuits will stop this from happening. If your doctor is recommending a treatment and Aetna denies coverage for that treatment and something goes wrong, then yes Aetna can and should be held liable, not your doctor.
People need to start lawyering up. It's not the doctor that is the problem, it is insurance.