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Refractory cardiogenic shock (RCS) represents the extremely-ill patients with STEMI, whose mortality rate was >60%. Despite the efforts to decrease door-to-balloon (D2B) time in the past decade, recent studies reported little progress on mortality of these patients. Meanwhile, early mechanical support such as ECMO has shown some favorable results when combined with primary PCI. D2B time delayed by ECMO has been a concern, but few studies addressed it.
From January 2005 to December 2014, 1969 patients presented with STEMI received emergent cardiac catheterization; revascularization was conducted by PCI or CABG as appropriate. ECMO was performed for 46 patients with RCS, defined as SBP <90mmHg under inotropes, refractory ventricular arrhythmia, or cardiac arrest. Demographic, hemodynamic, and angiographic data were collected retrospectively. Comparison was made between patients whose ECMO were set up before (N=12) and after (N=34) the cardiac catheterization.
Between two groups, there was no difference in age (before vs. after, 56.9 vs.57.5), male gender (91.7% vs. 85.3%), calendar year, GRACE score (median, 178 vs. 184), BP at ED (84/47 vs. 97/59) or before ECMO (50/34 vs. 58/32), number of diseased vessels (mean, 2.5 vs. 2.4), complete revascularization during PCI (41.7% vs. 23.5%, p=0.276), and TIMI 3 flow after PCI (81.8% vs. 56.0%, p=0.453). Patients with ECMO performed before PCI had a lower door-to-ECMO time (median 63 vs. 609 mins, p=0.019) and a nonsignificant longer D2B time (145 vs.115 mins, p=0.469); however, they had a significantly better 6-month survival (58.3% vs. 14.7%, p=0.006). After adjusting for gender, GRACE and D2B time, ECMO implemented before the cardiac catheterization is independently associated with 6-month survival (OR = 7.03 [95% CI 1.10-44.00], p= 0.039). All except 1 survivor had good neurological output.
Our data demonstrated a strong association between early ECMO implementation and survival in STEMI patients with RCS. Unlike previous studies, our finding highlights a new hypothesis – should we pause for ECMO before rushing for the D2B time? RCT is strongly needed to examine these results.
CORONARY: Acute Myocardial Infarction