Abstract Body: Background: Vasoplegia is persistent hypotension or sustained vasopressor requirement despite adequate fluid resuscitation, typically in the setting of elevated cardiac output. Extracorporeal cardiopulmonary resuscitation (ECPR) improves survival in patients with refractory cardiac arrest. However, the transition from a prolonged low-flow state to restored circulation often precipitates vasoplegic syndrome and subsequent circulatory collapse. The risk factors and outcomes of vasoplegic shock in ECPR are poorly defined.
Methods: We analyzed all patients with refractory cardiac arrest who underwent ECPR using peripheral VA ECMO cannulation at our center between 2015 and 2024. After excluding patients with severe bleeding or obstructive shock, a total of 367 patients were included in the analysis.
Results: In the first 24 h post ECMO cannulation, we identified two clusters: one with higher fluid balance (FB) and greater pressor use (P), and another with lower FB and lower P (Cluster A: N = 152, mean FB = 5938 ml, mean P = 2.89 vs Cluster B: N=215, mean FB=712 ml, mean P=1.01). Cluster A was older (59.1 vs 55.5 y, p=0.006), had higher BMI (32.2 vs 29.9, p= 0.003), more frequent HTN (55.8% vs 40.8 %, p=0.007) and use of ACE/ARB/ARNI ( 45% vs 32% p=0.02), CCB (20.7% vs 9.6%, p 0.006) and diuretics ( 34.5 % vs 23.7%, p=0.039); had more acidemia (Ph 7.23 vs 7.28, p=.006 and bicarb 17.6 vs 19, p=.004), higher lactate (13.2 vs 9.7, p<0.0001), lower temperature (92.4 vs 93.6, p=.04) and SVO2 (67.4 vs 70.6, p=.005), and higher need for IABP ( 69.7% vs 48.4% p<.001) and was treated with higher ECMO flows (3.8 vs 3.6 p=.0003). Cluster A had lower survival rates (10.5% vs 51.1%, p<.000001. Within cluster A, four quadrants were identified. The worst survival rates were in patients with high FB and high P (N=56,3.6% survival) followed by patients with high FB and low P (N=30, 6.7% survival) compared to patients with low FB and high P ( N=51, survival 17.6%) and patients with low FB and high p (N=15, survival 20%) (p=.049).
Conclusions: Higher FB and increased P use within the first 24 h of ECMO cannulation were associated with worse survival in patients undergoing ECPR. This phenotype is linked to prior antihypertensive medication use and lactic acidosis. Notably, higher FB was linked to worse outcomes compared to high P use, within the vasoplegic phenotype, raising important considerations about the detrimental effect of positive fluid balance in this patient population.