Objectives: Left ventricular (LV) re-remodeling after valvular surgery is insufficiently investigated and validated prediction parameters are still lacking. Myocardial native T1 is an imaging biomarker to quantify diffuse myocardial fibrosis and, therefore, may be helpful to predict LV re-remodeling in valvular cardiomyopathy. In our study, we aimed to evaluate whether myocardial native T1 is associated with the LV re-remodeling following valvular surgery.
Methods: We conducted a prospective cohort study which included all consecutive patients, referred to our institution for elective valvular surgery due to mitral or aortic regurgitation. Further inclusion criteria were (1) preoperative cardiac examination by cardiac magnetic resonance imaging (MRI) with assessment of native T1 values using a MOdified Look-Locker Inversion Recovery (MOLLI) sequence, (2) preoperative and (3) 6-month postoperative 2D transthoracic echocardiography with assessment of LV geometry parameters, (i.e., LVEDV, LVESV). Primary study endpoint was the correlation between preoperative native myocardial T1 values and postoperative change in LVEDV/LVESV at 6 months follow-up.
Result: A total of 79 consecutive patients (mean age: 56 ± 14 years; 73.4% male) with severe aortic regurgitation (n = 46) or severe functional mitral regurgitation (n = 33) were included. Operative procedures consisted of aortic valve repair (n = 30), aortic valve replacement (n = 16) and mitral valve repair (n = 33). Mean baseline native T1 in the whole study cohort was 1047 ± 39 msc. Mean ∆LVEDV (i.e., postoperative LVEDV – preoperative LVEDV) was −33 ± 42 mL and mean ∆LVESV was −15 ± 27 mL, respectively. Baseline native T1 values correlated significantly with the ∆LVEDV (Pearson r = 0.291; p = 0.009) and ∆LVESV (Pearson r=0.236; p=.05). After cut-off point analysis, native T1 < 1,073 millisecondsec was identified as an independent predictor of postoperative LVEDV improvement (i.e., ∆LVEDV < 0) (HR: 3.7; 95% CI: 1.0–13.6; p = 0.05). Postoperative LVESV improvement (i.e., ∆LVESV<0) showed only a tendency toward significant association with native T1 < 1,073 millisecondsec (HR: 3.0; 95% CI: 0.8–10.6; p = 0.09).
Conclusion: Cardiac MRI with T1 mapping is a valuable tool to quantitatively evaluate LV disease in valvular cardiomyopathy. We found a significant correlation between diffuse myocardial fibrosis measured by native T1 and postoperative change of LVEDV/LVESV (i.e., LV re-remodeling) at 6 months after valvular surgery. Native T1 values <1,073 millisecondsec may serve as an imaging biomarker of postoperative LV re-remodeling in patients with valvular heart disease, which should be validated in multicenter studies.
