Having a stent placed in the diagonal branch could possibly compromise the LAD if the placed stent extends beyond the ostium of the diagonal branch and has a portion remaining in the LAD. However, this would be highly unusual given the technology in both stents and in the methods of stent placement have advanced so much over the years. The reverse scenario (placing a stent in the LAD compromising the diagonal) is seen more often -- but again, is usually done in such a fashion that this can often be avoided in the hands of an experienced operator.
Thanks so much. That helps explain it better.