welcome to healthcare Magic
by your description of events, the possibility of cough syncope
is high, however since he has angina and has undergone stenting, the contribution of cardiac cause can not be definitely ruled out.
patients with situational syncope (like cough syncope) have better prognosis than patients with cardiac syncope. however it is not absolutely benign. moreover in your husband's case, since there is an underlying coronary artery
disease (anginal heart disease
)and COPD, the risk is more than a usual cough syncope because the drop in blood pressure during the episode may adversely effect cardiac circulation in diseased areas.
for a given patient, risk can not ascertained in numbers or percentage and moreover it depends upon the pumping of heart and state of diseased heart vessels in this particular case. i would recommend you to see the pulmonary medicine
specialist and your cardiac physician to ascertain actual risk (based on more information about the case) and more importantly to treat the cause for loss of consciousness
and prevent future episodes.
feel free to discuss further