Stress echocardiography and outcomes after cardiac surgery in patients with ischemic mitral regurgitation
Authors: Zagatina A , Shmatov D , Kim G , Ciampi Q , Citro R , Picano E ,   Stress Echo 2030 study group of the Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI)
Published: October 2021

Abstract

Background
Ischaemic mitral regurgitation (IMR) is a frequent complication of coronary artery disease. This is generally associated with double mortality rates. Poor prognosis could be observed despite successful cardiac surgery. There is a gap about predictors of further negative outcomes after surgical treatment. Owing to the dynamic nature of IMR, we hypothesize that multiparametric stress echocardiography (SE) would be helpful in assessing risk stratification. Aim: To evaluate the relationship between multiparametric SE parameters and outcomes after cardiac surgery in patients with IMR.

Methods
We prospectively enrolled 30 patients (62.7±8.5 yrs, 18 men), who have severe IMR by ESC classification, referred for coronary artery bypass grafting (CABG) with or without mitral surgery. Before cardiac surgery, the patients performed semi-supine bicycle multiparametric SE. Wall motion abnormalities, systolic and diastolic volumes of left ventricle, B-lines (lung congestion feature), left atrium volume, pulmonary pressure, mitral regurgitation volume, and effective regurgitation orifice area (EROA) were assessed before and during exercise. Ejection fraction (EF) and left contractile reserve were calculated. All-cause death was an endpoint.

Results
All patients had indications for CABG due to severe three-vessel disease. Before exercising, EF was 42±12%, end-diastolic volume was 167±49 ml, systolic volume of left ventricle was 86±39 ml, left atrium was 103±37 ml, global longitudinal strain was 12±4%, index of wall motion abnormality was 1.83±0.48, EROA was 0.39±0.22 cm2, regurgitation volume was 58±27 ml, systolic pulmonary pressure was 43±16 mmHg, and B-lines were 2.4±2. During exercise, EF was 44±17%, end-diastolic volume was 148±54 ml, systolic volume of left ventricle was 98±44 ml, index of wall motion abnormality was 2.30±0.49, EROA was 0.45±0.2 cm2, regurgitation volume was 70±32 ml, systolic pulmonary pressure was 51±14 mmHg, and B-lines were 5.4±3.3. A median follow-up time was 332 days (224–335). ROC analysis demonstrated that left ventricle end-diastolic volume during exercise (the cut-off value 192 ml, area under the ROC curve 0.77, p&lt;0.03), EROA during exercise (the cut-off value 0.37 cm2, the area 0.86, p&lt;0.0003), regurgitant volume during stress (the cut-off value 82 ml, the area 0.79, p&lt;0.02), the difference between stress and rest B-lines (the cut-off value 6 lines, the area 0.83, p&lt;0.0001), the difference between stress and rest EROA (the cut-off value 0.15 cm2, the area 0.77, p=0.05) were associated with death.

Conclusion
The stress echocardiographic parameters were associated with increased mortality after cardiac surgery in patients with IMR over the 1-year follow-up. B-lines (objective evidence of severe congestive heart failure), EROA, regurgitation volume (severity of mitral regurgitation during exercise) were all associated with worse outcome. These preliminary results should be confirmed in the larger studies.

Funding Acknowledgement
Type of funding sources: None.