The risks here are a guide; your own risk may vary. You should discuss the risks and benefits of surgery with your surgeon, especially if you are worried. Since you will already have severe lung disease the risks of an anaesthetic are higher.
Minor more common risks
You may feel feverish for a few hours after surgery. You may have a hoarse voice at first, this should settle. Air may escape from the lung and get into the space between the lung and the chest wall; this is called a pneumothorax (also known as a collapsed lung). If this occurs you will need to stay in hospital have a chest drain to remove the air. A pneumothorax is more likely to occur if the valve works very well and collapses the area of emphysema quickly. Chest pain and shortness of breath may be signs of a pneumothorax. The valve may become dislodged or more rarely you may cough up a valve, this is not dangerous but of course this valve is no longer working. Another valve can be fitted if you found the valve helped. You may notice an increase in mucous or wheezing, a flare up of your emphysema symptoms may happen that needs treatment. You may get a chest infection after surgery that requires treatment. You cough up a small amount of blood.
Major less common risks
A collapsed lung may be difficult to treat with a chest drain and the valves may have to be removed. A flare up of your emphysema symptoms or chest infection may become severe. Shortness of breath from these problems may become severe enough to require help from a ventilator machine or be fatal. This can be with a face mask with you fully awake. It may also be need via a tube in your windpipe with you under sedation. If you need help breathing via a tube for a long time it may be better to have a temporary tracheostomy. This is a tube put in through the neck which is removed once breathing improves. Coughing up a large amount of blood can happen but is very rare.