Should a patient have a nuclear stress test more than once a year? is once a year appropriate or could that even be too frequent?

Depends: This depends upon how risk factors you have for coronary artery disease like prior heart attack, angioplasty, diabetes, hyperlipidemia, high coronary calcium score on ct,strong family history, strong smoking history, previously abnormal stress tests, suspicious symptoms, abnormal EKG.,presence of other vascular disease. Otherwise yearly nuclear stress testing is excessive and not recommended