While Khosrau II did bring the Sassanids to their greatest extent in the Byzantine-Sassanid war of 602-628, he managed to also overtax his citizens, make them angry, overextend the state, and test the limits of Persia. In addition, he crippled Greek urban life in the Levant by destroying most of Antioch and turning Syria into a ghost of its former self. After that both ERE and the Persian state were sufficiently weakened so as to succumb to the Caliphate. In the end they managed to destroy each other.
Originally Khosrau invaded the ERE after Narses, former governor of Mesopotamia seized Edessa and rebelled against Phocas. When he was besieged by Germanus, He called Khosrau for help and that opened the gates of hell.
However, what if the rebellion was nipped in the bud, and Khosrau was distracted by central Asian nomads moving in on Kushan and Merv?
Is this enough to make Khosrau stay away? If not, how else is it possible?