Disparity of Performance Measure by Door-to-Balloon Time Between a Rural and Urban Area for Management of Patients With ST-Segment Elevation Myocardial Infarction　- Insights From the Nationwide Japan Acute Myocardial Infarction Registry.

BACKGROUND
Although a door-to-balloon (D2B) time ≤90 min is recognized as a key indicator of timely reperfusion for patients with ST-segment elevation myocardial infarction (STEMI), it is unclear whether regional disparities in the prognostic value of D2B remain in contemporary Japan.Methods and Results: We retrospectively analyzed 17,167 STEMI patients (mean [±SD] age 68±13 years, 77.6% male) undergoing primary percutaneous coronary intervention. With reference to the Japanese median population density of 1,147 people/km2, patients were divided into 2 groups: rural (n=6,908) and urban (n=10,259). Compared with the urban group, median D2B time was longer (70 vs. 62 min; P<0.001) and the rate of achieving a D2B time ≤90 min was lower (70.7% vs. 75.4%; P<0.001) in the rural group. In-hospital mortality was lower for patients with a D2B time ≤90 min than >90 min, regardless of residential area, whereas multivariable analysis identified prolonged D2B time as a predictor of in-hospital death only in the rural group (adjusted odds ratio 1.57; 95% confidence interval 1.18-2.09; P=0.002). Importantly, the rural-urban disparity in in-hospital mortality emerged most distinctively among patients with Killip Class IV and a D2B time >90 min.


CONCLUSIONS
These data suggest that there is a substantial rural-urban gap in the prognostic significance of D2B time among STEMI patients, especially those with cardiogenic shock and a prolonged D2B time.