Deteriorated mechanics of left ventricular diastolic filling one year after coronary artery bypass grafting
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Background
Ischemic heart disease impairs left ventricular (LV) diastolic function, but little is known about changes in the mechanical properties of LV relaxation following coronary artery bypass grafting (CABG).
Objectives
This study aimed to explore if and how the mechanics of LV filling change following CABG.
Methods
Patients underwent transthoracic echocardiography before and one year after elective CABG. Mitral inflow E-waves were analyzed using the parameterized diastolic filling (PDF) method, allowing for quantification of mechanical properties of diastolic function.
Results
Among patients (n=96, 10% female, median [interquartile range] age 68 [62–74] years), LV ejection fraction (LVEF) at baseline was 59 [53–63] %. At follow-up, there was an increase in the PDF-derived measures of myocardial stiffness, damping, peak driving and resistive forces, and filling energy, together with increase in left atrial (LA) volume index, and a decrease in LA conduit and contractile strains and tricuspid annular plane systolic excursion (p<0.001 for all). There was no change in heart rate, LV size, LVEF, E/é ratio, or LV filling efficiency. Furthermore, there were no differences in the mechanics of LV filling in patients when grouped according to baseline LVEF, or the number of revascularized coronary arteries.
Conclusions
One year after CABG, there was consistent deterioration in the mechanics of diastolic filling assessed using comprehensive conventional and mechanistic evaluation. Revascularization with CABG may worsen diastolic function one year after CABG. However, causes and significance of these changes remain to be further investigated.
Abstract Figure
Central illustration.Deterioration in LV diastolic properties one year after CABG.
Overview of background, study design, methods and main results. Abbreviations: LV – Left Ventricular; CABG – Coronary artery bypass graft surgery; CMR – Cardiovascular magnetic resonance; ECHO – transthoracic echocardiography.
