Usefulness of Lung Impedance-Guided Pre-Emptive Therapy to Prevent Pulmonary Edema During ST-Elevation Myocardial Infarction and to Improve Long-Term Outcomes

Patients sustaining an ST-segment elevation myocardial infarction (STEMI) frequently develop pulmonary congestion or pulmonary edema (PED). We previously showed that lung impedance (LI) threshold decrease of 12% to 14% from baseline during admission for STEMI marks the onset of the transition zone from interstitial to alveolar edema and predicts evolution to PED with 98% probability. The aim of this study was to prove that pre-emptive LI-guided treatment may prevent PED and improve clinical outcomes. Five hundred sixty patients with STEMI and no signs of heart failure underwent LI monitoring for 84 ± 36 hours. Maximal LI decrease throughout monitoring did not exceed 12% in 347 patients who did not develop PED (group 1). In 213 patients LI reached the threshold level and, although still asymptomatic (Killip class I), these patients were then randomized to conventional (group 2, n = 142) or LI-guided (group 3, n = 71) pre-emptive therapy. In group 3, treatment was initiated at randomization (LI = −13.8 ± 0.6%). In contrast, conventionally treated patients (group 2) were treated only at onset of dyspnea occurring 4.1 ± 3.1 hours after randomization (LI = −25.8 ± 4.3%, p