Clinical associations of subclinical pulmonary congestion in patients with primary acute myocardial infarction after percutaneous coronary intervention

Aim

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).

Results

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.

Conclusion

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.

Key words

Acute myocardial infarction, subclinical pulmonary congestion, B-lines, 6-minute walk test.