Direct transfer of STEMI patients to cath lab reduces mortality


Lindsay L Anderson (Department of Medicine, Duke Clinical Research Institute, Duke University Medical Center, Durham, USA) and others report in Circulation: Cardiovascular Interventions that directly transferring patients with ST-segment elevation myocardial infarction (STEMI) from the referring hospital to the cath lab—rather other departments (such as the emergency department)—of the receiving hospital is associated with significant reductions in time to reperfusion and mortality.

Anderson et al report that US guidelines recommend “expedited transfer of eligible STEMI patients to a PCI-capable hospital for primary percutaneous coronary intervention (PCI) with a first medical contact-to-device time goal of ≤120 minutes.” However, they add that reperfusion goals “are still not being achieved for most transferred patients”. Therefore, the authors note, a strategy of directly transferring STEMI patients to the cath lab of the referring hospital rather than the emergency department or other area of the hospital may help to reduce treatment delays. To evaluate this approach, Anderson et al reviewed data from the ACTION Registry-GWTG (National cardiovascular data registry acute coronary treatment and intervention outcomes network registry—Get With the Guidelines) to determine how many STEMI patients (in the USA) are directly transferred to the cath lab and if direct transfer to the cath lab affects patient outcomes.

Of 33,901 STEMI patients transferred from a referring hospital to a PCI-capable hospital between 2008 and 2012, 26,510 (78%) were directly transferred to the cath lab—with the remaining 7,391 patients being transferred to the emergency department (47% of patients in this group) or to a hospital ward (53.6%). Anderson et al report that few patients who were not directly transferred to the cath lab had a non-system reason for reperfusion delay (ie. cardiac arrest), with only 28% of patients in this group presenting with such a reason. However, more patients in the non-direct transfer had non-system reason for reperfusion delay than had the patients in direct transfer group (14%). The authors add: “Patients transferred directly to the cath lab were more likely to arrive during business hours (33% vs. 29%; p<0.0001) and travelled shorter distances between hospitals.”

Among the patients who received primary PCI, time to treatment was significantly shorter in the direct transfer group: 116 minutes vs. 191 minutes for the non-direct transfer group (p<0.0001). Time to treatment remained shorter for the direct transfer group after patients with a non-system reason for reperfusion were excluded from the analysis: 50 minutes vs. 70 minutes, respectively (p<0.0001).

According to Anderson et al, multivariate analysis showed that the risks of in-hospital death and heart failure were significantly lower for direct transfer patients than for non-direct transfer patients. They state: “Furthermore, the unadjusted and adjusted risks of death remained significantly lower for patients transferred to the cath lab compared with those transferred to a hospital or to the emergency department when analysed separately.”

The authors note that their study “supports the wide adoption of direct transfer to the cath lab across United States hospitals” but add that “several factors” require consideration. One such factor, they explain, is whether the US healthcare system threshold for false activation of the cath lab for suspected STEMI patients should be raised given that they found equivocal ECG findings was the strongest factor limiting direct transfer to a cath lab (though only 7% of patients in the non-direct transfer group had such findings) and given that non-direct transfer patients had greater reperfusion delays. “Better infrastructure to support ECG transmission and expedite decision-making would facilitate quality improvement for transfer patients,” Anderson et al comment. They add that another factor to consider is the need to reduce delays between the STEMI diagnosis and decision to transfer, the transfer destination, and ambulance availability to transport the patient and note: “Continued efforts to coordinate care and facilitate real-time decision-making between STEMI referral hospitals, emergency medical services, and STEMI receiving hospitals should help mitigate these logistic barriers.”

Study author Tracy Y Wang (Department of Medicine, Duke Clinical Research Institute, Duke University Medical Center, Durham, USA) told Cardiovascular News: “If a STEMI diagnosis is already confirmed at another hospital, the imperative is to get this patient reperfused as soon as possible. Transferring patients directly to the cath lab can substantially shorten delays to reperfusion, and should be the default strategy.  There is concern that transferring more STEMI patients directly to the cath lab may waste resources due to false activations. These are unavoidable, but also uncommon. It is clear where our priorities should lie.”