What are the clinical differences between patients achieving a door-to-balloon (DTB) time of 90 minutes versus 60 minutes?

From the Guidelines

Patients achieving a door-to-balloon time of 60 minutes have better clinical outcomes compared to those with a 90-minute timeframe, with reduced morbidity, mortality, and improved quality of life. The clinical differences between these two groups are primarily related to myocardial salvage and outcomes. Patients with the shorter 60-minute timeframe typically experience less myocardial damage, lower peak troponin levels, and better preservation of left ventricular ejection fraction 1. These patients generally have smaller infarct sizes, reduced risk of heart failure development, and lower incidence of cardiogenic shock. Mortality rates are also lower in the 60-minute group, with studies showing approximately 1% absolute mortality reduction for each 10-minute reduction in door-to-balloon time.

Some key points to consider when evaluating door-to-balloon times include:

• The current guideline target remains 90 minutes, but the evidence suggests that further mortality benefits can be achieved by targeting the shorter 60-minute timeframe, especially in high-risk populations 1.
• The clinical benefit of achieving the 60-minute target is particularly pronounced in high-risk patients, including those with anterior ST-elevation myocardial infarction, cardiogenic shock, and elderly patients.
• Myocardial necrosis progresses in a time-dependent manner during coronary occlusion, with the "golden hour" representing the critical window when myocardial salvage potential is highest.
• The PCI-related delay that may mitigate the benefit of mechanical intervention varies between 60 and 110 min, and an individualized approach for selecting the optimal reperfusion modality could be more appropriate when PCI cannot be performed 1.

Overall, the evidence suggests that achieving a door-to-balloon time of 60 minutes is associated with improved clinical outcomes, including reduced morbidity, mortality, and improved quality of life, and should be the target for patients with ST-elevation myocardial infarction whenever possible.

From the Research

Clinical Differences Between Patients Achieving a Door-to-Balloon Time of 90 Minutes Versus 60 Minutes

• The clinical differences between patients achieving a door-to-balloon (DTB) time of 90 minutes versus 60 minutes are significant in terms of prognosis and mortality rates 2, 3, 4.
• Patients with a DTB time of less than 60 minutes had better thrombolysis in myocardial infarction (TIMI) flow and lower 30-day mortality rates compared to those with a DTB time of 60-90 minutes 2.
• A study found that reducing DTB time within 45 minutes showed further decreased risk of mortality compared to DTB time greater than 90 minutes, with an absolute risk reduction of 2.4% and a number needed to treat of 41.9 3.
• Every reduction of DTB time by 30 minutes showed continuous reduction of 1-year mortality, with an absolute risk reduction of 2.0% and a number needed to treat of 49.2 for DTB time reduced from 60 to 30 minutes 3.
• Another study found that any delay in primary percutaneous coronary intervention (PCI) is associated with increased 1-year mortality, suggesting efforts should focus on decreasing time to treatment as much as possible, even among those centers currently providing primary PCI within 90 minutes 4.

Factors Influencing Door-to-Balloon Time

• Several critical innovations can help reduce DTB time, including the use of pre-hospital electrocardiograms (ECGs) to activate the catheterization laboratory, allowing emergency physicians to activate the catheterization laboratory, and substantial interdisciplinary collaboration throughout the process 5.
• Implementing the Lean Six Sigma methodology can also result in decreased median DTB time and increased percentage of patients who underwent PCI within 90 minutes 6.

Mortality Rates and Door-to-Balloon Time

• Longer DTB times are associated with higher 1-year mortality in a continuous, nonlinear fashion, with any increase in DTB time associated with successive increases in patients' 1-year mortality 4.
• A study found that the nature of the association between DTB time and 1-year mortality was best modeled by a second-degree fractional polynomial, with findings similar after multivariable adjustment 4.