Complex sentence: The result is that there is "no" first appeal of right for the vast majority of cases, and in turn, the vast majority of decisions of trial courts in those states are thereby insulated from appellate review on the merits.
Split into simpler sentences: The result is that there is "no" first appeal of right for the vast majority of cases. In turn, the vast majority of decisions of trial courts in those states are thereby insulated from appellate review on the merits.