Short and long-term outcome of impedance-guided preemptive therapy provided to prevent pulmonary congestion-edema in the course of acute myocardial infarction

Abstract

Background: Patients sustaining an acute myocardial infarction (AMI) frequently develop pulmonary edema (PED). Currently, treatment is initiated after the appearance signs of lung fluid overload. Ongoing monitoring of the status of lung fluid content (LFC) may enable the prediction of impending PED. Aims: To find out whether non-invasive lung impedance (LI) guided preemptive diuretic treatment of AMI patients developing PED improves clinical outcomes. Methods: A net LI was determined by using a new noninvasive method. Any increase in LFC results in LI decrease. Previously we have found that a decrease of 12-14% from normal LI value reflects the beginning transition from interstitial to alveolar edema. In this study we prospectively randomized 222 patients (2:1 ratio) admitted for AMI without chronic heart failure (CHF) and signs of PED at admission and who expressed a O12% LI decrease to conventional therapy or LI-guided preemptive diuretic treatment. Results: 148 patients were treated conventionally (Gr1) and 74 preemptively according LI (Gr2). Groups were well matched. In Gr1 all patients developed different stages of PED. Treatment was begun only at symptom onset. In Gr2 LI-guided preemptive treatment was started immediately after randomization at asymptomatic stage of evolving PED and halted its development in 89% of patients. Unadjusted analysis shown that hospital stay, 1-year re-hospitalization rate after discharge, 6-years development new CHF and survival rate was better in Gr2 patients (p<0. 001). Adjustment for such parameters as age, LVEF, maximal CK, diabetes, hypertension, hyperlipidemia, smoking, level of creatinine and hemoglobin at admission shown that LI-guided preemptive treatment improved clinical outcome. Length of hospital stay reduced (OR=5.35, CI: 3.2-8.1, p<0.0001), 1-year re-hospitalization rate reduced (OR=3.7, CI: 2.2-6.1, p<0.001), 6-years occurrence of new CHF reduced (OR=3.5, CI: 1.3-7.5, p=0.002) and 6-years survival rate was better (OR=3.2, CI: 1.2-9.1, p=0.027). Off different clinical and laboratory parameters the major influence on clinical outcome had age, diabetes mellitus, LVEF <30% and maximal CK (>2220 mg/dl), (p<0.001). Conclusions: LI-guided preemptive therapy halts progression to PED in 89% of patients, and significantly reduces hospital stay, recurrent admissions, evolution of CHF and mortality.