To evaluate the frequency, severity and associations of subclinical pulmonary congestion assessed with lung ultra50 sound before and after 6-minute walk test (6MWT) at discharge of patients with primary acute myocardial infarction (AMI).
Material and methods
In a single-center observational study, 103 patients with AMI after percutaneous coronary intervention (PCI) (average age 62.1±11.8 years, 66.9% males, Killip I in 88.3% and Killip II in 11.7%) underwent lung ultrasound before and after 6MWT at discharge from the hospital to evaluate the presence and severity of subclinical pulmonary congestion. The sum of B-lines was counted in 4 zones (each zone was assigned a score of 0 [A-lines] to 10 [white lung]). Subclinical congestion was assessed as mild (2-4 Blines), moderate (5-9) or severe (≥10).
The number of B-lines was ≥2 in 96.1% of patients. Most of them (75.1%) had mild or moderate subclinical pulmonary congestion. After 6MWT there was an increase in the median of B-lines from 5 (4; 8) to 8 (5; 12), or by 25% (p=0.000). The number of patients with mild congestion decreased from 31.1% up to 18.4%, whereas the number of patients with severe congestion increased from 20.3% up to 42.7%. Left ventricular (LV) ejection fraction <50%, LV wall motion abnormality, Killip class II and a history of atrial fibrillation predicted the increase in pulmonary congestion after 6-minute walk test.
Sum of B-Lines on lung ultrasound after 6MWT can be a useful tool for identifying and assessing the severity of subclinical congestion in patients with AMI after PCI.
Acute myocardial infarction, subclinical pulmonary congestion, B-lines, 6-minute walk test.