Nearly one in seven STEMI patients presenting at centers with PCI capabilities experienced nonsystem delays in door-to-balloon-time (D2BT), and mortality rates were significantly higher in that patient group compared with nondelayed patients.
Sicker patients rather than the delays themselves likely account for higher mortality, according to the researchers and the authors of an accompanying editorial. The study and editorial were published April 23 In the Journal of the American College of Cardiology.
PCI is the most common reperfusion strategy in the U.S. for STEMI patients, with early and complete reperfusion associated with better outcomes. The recommended window is 90 minutes D2BT, but nonsystem reasons can cause delays. Those reasons include delays getting consent, difficult vascular access, difficulty crossing the culprit lesion and cardiac arrest requiring intubation.
Rajesh V. Swaminathan, MD, of New York Presbyterian Hospital in New York City, and colleagues hypothesized that such nonsystem delays occurred frequently and were associated with higher mortality and adverse events. To test that, they used the National Cardiovascular Data Registry, which collects data from approximately 60 percent of the cath labs in the U.S. and includes D2BT, nonsystem reasons for delays and outcomes.
Their study analyzed data from 82,678 STEMI patients who underwent primary PCI between Jan. 1, 2009 and June 30, 2011. Nonsystem delays occurred in 14.7 percent of those patients, with median D2BT of 92 minutes compared with 65 minutes for nondelayed patients. The most frequent reason was cardiac arrest/intubation (37.4 percent), followed by other (31 percent), difficulty crossing the culprit lesion (18.8 percent), difficult vascular access (8.4 percent) and delays in providing procedure consent (4.4 percent).
Patients and who experienced nonsystem delays were more likely to be older, female, African American and have greater comorbidities. The in-hospital mortality rate for patients with nonsystem delays was 15.1 percent compared with 2.5 percent for patients with no delays. Rates of adverse outcomes such as cardiogenic shock and congestive heart failure also were higher in patients with nonsystem delays.
Nonetheless, 47 percent of patients with nonsystem delays had D2BT of 90 minutes or less. Cardiac arrest/intubation before PCI, with a median D2BT of 84 minutes, was the most frequent reason for delay and it was associated with a 30 percent in-hospital mortality rate, the highest for individual reasons.
Their analysis showed that nonsystem delays “were related to patient comorbidities and higher risk presentation rather than greater ischemic time from a substantial delay in reperfusion,” they wrote “This is in contrast to other analyses on system delays and D2BT, which report an increase in associated mortalities with incremental time delays in D2BT.”
The authors emphasized that most of the reasons for nonsystem delays were due to advanced disease not modifiable, with the exception of delays in consent, which as associated with a mortality rate of 9.4 percent.
“[T]he consenting process may provide an opportunity for substantial improvement and reduction in delays,” Swaminathan et al suggested. “For example, healthcare providers initially treating and triaging patients should be permitted to begin conversations regarding the procedure with the patient and family so as to expedite obtaining the informed consent by a member of the PCI team.”
Editorialist Cindy L. Grines, MD, and Theodore L. Schreiber, MD, both of the Detroit Medical Center Cardiovascular Institute, reiterated that delay “most likely is a marker for higher risk patients, and the extent of the risk is difficult to ascertain in retrospective studies.”
The fact that 31 percent of reasons fell in the “other” category also posed limitations, they wrote.
They argued that the focus on D2BT may have some unwanted consequences, such as incentivizing physicians to provide thrombolytic therapy rather than PCI to sicker patients whose D2BT possibly would exceed the 90-minute guidelines. “To further improve prognosis, physicians need to focus more on providing primary PCI to more patients, especially the STEMI cases at highest risk,” they urged.