Association Between 90-Minute Door-to-Balloon Time, Selective Exclusion of Myocardial Infarction Cases, and Access Site Choice: Insights From the Cardiac Care Outcomes Assessment Program (COAP) in Washington State

Abstract

Background: For patients presenting with ST-segment-elevation myocardial infarction, national quality initiatives monitor hospitals' proportion of cases with door-to-balloon (D2B) time under 90 minutes. Hospitals are allowed to exclude patients from reporting and may modify behavior to improve performance. We sought to identify whether there is a discontinuity in the number of cases included in the D2B time metric at 90 minutes and whether operators were increasingly likely to pursue femoral access in patients with less time to meet the 90-minute quality metric.

Methods: Adult patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention from 2011 to 2018 were identified from the Cardiac Care Outcomes Assessment Program, a quality improvement registry in Washington state. We used the regression discontinuity framework to test for discontinuity at 90 minutes among the included cases. We defined a novel variable, remaining D2B as 90 minutes minus the time between hospital arrival and catheterization laboratory arrival. We estimated multivariable logistic regression models to assess the relationship between remaining D2B time and access site.

Results: A total of 19 348 patients underwent primary percutaneous coronary intervention and were included in the analysis. Overall, 7436 (38.4%) were excluded from the metric. There appeared to be a visual discontinuity in included cases around 90 minutes; however, local quadratic regression around the 90-minute cutoff did not reveal evidence of a significant discontinuity (P=0.66). Multivariable analysis showed no significant relationship between remaining D2B time and the odds of undergoing femoral access (P=0.73).

Conclusions: Among patients undergoing percutaneous coronary intervention for ST-segment-elevation myocardial infarction, we did not find evidence of a statistically significant discontinuity in the frequency of included cases around 90 minutes or an increased preference for femoral access correlated with decreasing time to meet the 90-minute D2B time quality metric. Together, these findings indicate no evidence of widespread inappropriate methods to improve performance on D2B time metrics.

Keywords: association; catheterization; hospitals; myocardial infarction; percutaneous coronary intervention.

Figure 1:

Histograms of the frequency of D2B times are presented for the entire study cohort (A) and for those patients remaining after application of exclusion criteria for inclusion into the D2B time quality metric (B). The difference between the excluded patients (green) and the included patients (yellow) is demonstrated in (C). An overlaid distribution centered at 90 minutes of included and excluded cases is presented in (D).

Figure 2:

Regression discontinuity plots with a local quadratic approximation of primary PCI D2B times for cases included when calculating the D2B time metric using 5-minute (A) and 10-minute windows (B). The x-axis represents D2B time and the y-axis represents the density of number of cases around the 90 minute cutoff.

Figure 3:

Percentage of radial versus femoral access shown with varying rD2B time.