It sounds as if your cardiologist may need to educate himself or re-educate himself about WLS. My cardiologist is the one who suggested WLS to me. I thought I would be unable to have it due to my many health issues but he said I should be fine as long as we came up with a plan on how to proceed.
I have several doctors that are all working together to support my decision to have the surgery (VSG), my primary care physician, cardiologist, pulmonologist and WLS surgeon have all worked to get me ready for the surgery. I am now just waiting for insurance to approve and to get a date set.
I would ask your WLS surgeon what cardiologist he recommends or find another cardiologist for a second opinion. I wish you all the best and remember we have to be proactive in our health care.