It is difficult to anticipate the consequences of guidelines and how they affect practice. The 90-minute door-to-balloon (D2B) window for reperfusing STEMI patients may be a case in point.
D2B is considered an important quality indicator in the care of patients who present with STEMI. Based on evidence that swift and complete reperfusion affects mortality rates, the American College of Cardiology recommends that STEMI patients receive angioplasty within 90 minutes of arrival to a hospital.
An analysis of CathPCI registry data from 2010 to 2011 found the median time from hospital arrival to PCI for nontransferred STEMI patients was 64.5 minutes, well under the 90-minute recommendation. This month in the Journal of the American College of Cardiology, Swaminathan et al looked at nonsystem delays in D2B times for primary PCI, also using data from the CathPCI Registry. Their study spanned 2009 to 2011 and analyzed results based on reasons such as cardiac arrest that require intubation or difficult vascular access.
Thirteen percent of patients with no nonsystem delays exceeded the 90-minute window compared with 53 percent of patients with nonsystem delays. Overall, the patients with nonsystem delays had poorer outcomes, with an in-hospital mortality rate of 15.1 percent vs. 2.5 percent. Yet patients delayed by cardiac arrest who required intubation had the highest mortality rate (29.9 percent) despite a median D2B time of 84 minutes.
With the exception of delays in getting consent, the nonsystem delays in the study appeared to be due to patient factors: These patients were sicker. Tying quality to D2B, in these cases, may fail to recognize the complexity and challenges associated with such patients.
Many hospitals have identified system-related issues that contributed to delays and made modifications to remove them. Most of the nonsystem delays are not modifiable, Swaminathan et al underscored. But delays in obtaining procedure consent offered one opportunity to improve D2B time and outcomes in these sicker patients.
In an accompanying editorial, Cindy L. Grines, MD, and Theodore L. Schreiber, MD, both of the Detroit Medical Center, voiced concerns that efforts to meet or do better than the 90-minute D2B time may lead to less measured diagnoses and “misdiagnoses and inappropriate treatment in a minority of suspected STEMI cases.”
Grines and Schreiber also offered the possibility that some physicians may be inclined to game the system to maintain low D2B times by giving sicker patients thrombolytic therapy rather than PCI. “[T]his strategy may not be in the patient’s best interest,” they wrote.
D2B is generally a success, and many patients have benefited from the 90-minute guideline. But perhaps it is time to look beyond the clock to ensure physicians and institutions that “do right” by the patient aren’t unfairly dinged on quality.
Cardiovascular Business, editor