Time Delay, Infarct Size, and Microvascular Obstruction After Primary Percutaneous Coronary Intervention for ST-Segment–Elevation Myocardial Infarction

Abstract

Background : Symptom-to-balloon time (SBT) and door-to-balloon time (DBT) are both considered important metrics in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction (STEMI). We sought to assess the relationship of SBT and DBT with infarct size and microvascular obstruction (MVO) after pPCI. Methods : Individual patient data for 3115 STEMI patients undergoing pPCI in 10 randomized trials were pooled. Infarct size (% left ventricular mass) was assessed within 1 month after randomization by technetium-99m sestamibi single-photon emission computerized tomography (SPECT, 3 studies) or cardiac magnetic resonance imaging (CMR, 7 studies). MVO was assessed by CMR. Patients were stratified by short (≤2 hours), intermediate (2-4 hours), or long (>4 hours) SBTs, and by short (≤45 minutes), intermediate (45-90 min), or long (>90 minutes) DBTs. Results : Median [IQR] SBT and DBT were 185 [130-269] and 46 [28-83] minutes, respectively. Median [IQR] time to infarct size assessment after pPCI was 5 [3-12] days. There was a stepwise increase in infarct size according to SBT category (adjusted difference 2.0%, 95% confidence interval [CI] 0.4-3.5 for intermediate versus short SBT and 4.4%, 95%CI 2.7-6.1 for long versus short SBT) but not according to DBT category category (adjusted difference 0.4%, 95% CI -1.2 to 1.9 for intermediate versus short DBT and -0.1%, 95% CI -1.0 to 3.0 for long versus short SBT). MVO was greater in patients with long versus short SBT (adjusted difference 0.9%; 95% CI 0.3-1.4) but was not different between patients with intermediate versus short SBT (adjusted difference 0.1; 95% CI -0.4 to 0.6). There was no difference in MVO according to DBT. Results were similar in multivariable analysis with SBT and DBT included as continuous variables. Conclusions : Among 3115 patients with STEMI undergoing infarct size assessment after pPCI, SBT was more strongly correlated with infarct size and MVO than DBT.

Progress in regional systems of care for STEMI in low- and middle-income countries

“…Times to hospital presentation and first door-to-balloon times were strikingly prolonged, with a dramatic adverse impact on mortality and rates of cardiogenic shock. These data reinforce both dramatically and tragically the time-honoured concept of "time is muscle" 1,8,17 .…”

Reducing the total ischaemic time in ST-segment elevation myocardial infarction: Every step matters

“…We should collect routine data on "symptomto-balloon" (STB) time as this reflects the total ischaemic time and had been shown to correlate better with infarct size and left ventricular ejection fraction compared to DTB time. 17 Importantly, the STB time incorporates a patient's dimension into the quality matrix as it includes the time from symptom onset to first medical contact (the "patient delay") and reflects the success of our public educational efforts. The trends of both DTB time and STB time should be monitored in a national STEMI registry with steps taken to identify and address system and non-system related delays.…”

Association between total ischemic time and in-hospital mortality after emergency PCI in patients with acute ST-segment elevation myocardial infarction: a retrospective study

“…Shiomi et al [ 18 ] also found that AMI patients with a short SBT (< 3 h) had a lower risk of mortality and heart failure than those with a long SBT (> 3 h), but patients with DBT > 90 min and those with DBT < 90 min had a similar risk of mortality and heart failure; only when SBT < 120 min, the risk of mortality and heart failure in AMI patients with DBT < 90 min was reduced. It suggested that SBT can better reflect the degree of myocardial injury and necrosis than DBT, thereby affecting the outcomes of patients, as suggested by more recent studies [ 14 , 16 , 20 ]. Like these studies, the present study revealed that with the prolongation of SBT, the risk of in-hospital mortality in AMI patients with EF < 50% was increased, but there was no increase in the risk of mortality in AMI patients with EF ≥ 50%, which has not been observed in previous studies.…”

“…Among the factors mentioned above, SDT represents the time during which the patient is without medical care and during which damage is uncontrolled, without specific treatments at all, and it is associated with the prognosis of PCI [ 14 , 16 ]. On the other hand, the door-to-balloon time (DBT) represents when a patient is monitored and might receive medical treatments, but definitive treatment has not yet been undertaken; it is positively associated with the patient’s mortality [ 14 , 16 ].…”

“…Among the factors mentioned above, SDT represents the time during which the patient is without medical care and during which damage is uncontrolled, without specific treatments at all, and it is associated with the prognosis of PCI [ 14 , 16 ]. On the other hand, the door-to-balloon time (DBT) represents when a patient is monitored and might receive medical treatments, but definitive treatment has not yet been undertaken; it is positively associated with the patient’s mortality [ 14 , 16 ]. Differently, the SBT represents the entire myocardial ischemic period; it has no definite relationship with the short-term patient’s mortality [ 17 , 18 ], but a recent study suggested a positive correlation between SBT and long-term mortality of patients with AMI after PCI [ 16 ].…”