Variability in maximal suggested door-in-door-out time for hospitals transferring patients for primary angioplasty in STEMI.

Objectives: We derived a formula for maximal suggested door-in-door-out time (DIDO) for hospitals that do not perform primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI).

Background: Efforts to minimize DIDO at non-PCI hospitals can improve door-to-balloon time (D2B). Targeting a maximal suggested DIDO for a transferring hospital can influence reperfusion strategy.

Methods: We examined time to treatment intervals for 193 STEMI patients who underwent primary PCI at our hospital. D2B in transferred patients (D2BT ) was divided into 3 intervals: transferring hospital DIDO, inter-hospital transport time, and interventional time. We defined maximal suggested DIDO as the maximum DIDO that would allow PCI with D2BT ≤ 120 minutes.

Results: D2B was higher in transfer compared to on-site patients (147 ± 52 vs. 75 ± 44 minutes, P < 0.0001). In transfer patients, treatment time intervals were: DIDO 80 ± 42 minutes, transport time 37 ± 18 minutes, interventional time 35 ± 16 minutes. The greatest variability in D2BT was related to DIDO. We estimated that maximal suggested DIDO = [120 - (transport time plus interventional time)]. Using a fixed interventional time of 40 minutes, we simplified this as: maximal DIDO = 80 - transport time. Maximal suggested DIDO for 4 transferring hospitals in our network ranged from 1 to 65 minutes. DIDO under the hospital-specific threshold was the strongest predictor of achieving D2BT <120 minutes.

Conclusions: Transferring hospitals' maximal suggested DIDO is variable, and can be calculated from inter-hospital transport time. Instead of a universal target DIDO (e.g., <30 minutes), maximal suggested DIDO can be calculated individually for each non-PCI hospital within a STEMI network.