Sleeve Info, is the Way They Do It in the UK Safe?

I live in the UK and have been researching my options on weightloss surgery, i came across a video that a doctor uploaded on here showing how the sleeve op is performed, it showed that they stapled the stomach and removed the bit that was no longer used, in the UK ive noticed they staple through the stomach but dont seperate the unused bit from the new smaller pouch, is this safe? i would of thought the staples would of cut off blood supply and would rot or cause probs in your body???