Hard to say without more details, though it's certainly plausible.
There's other possibilities though. Like if the timing of other interventions is being delayed until the cardiologist is able to see the patient instead of deferring to a less specialized physician.
No, not necessarily. There's no indication of that whatsoever. The point was just that there's insufficient information to conclude much of anything about why this was observed. It could also be that PCI is over applied leading to increased mortality.