Does sleep apnea cause heart disease very quickly(few years)? or is heart disease more associated with long standing sleep apnea(many years/decades)?

Depends on severity: & resulting severity of: hypoxemia, resulting pulmonary hypertension & severity of underlying coronary artery disease (in 1/2 of US citizens by age 7, per >8 decades US autopsy studies; yet asymptomatic for decades; arteries enlarge: http://goo.gl/aRhOU2. Narrowings, most clinically silent, result from sudden plaque ruptures & clots). Thus there is no reliable answer-too many individual variables.