Unmasking early diastolic dysfunction in type 2 diabetes using the peak early-to-late diastolic strain rate ratio by cardiac MRI feature tracking

Abstract

Abstract Introduction Type 2 diabetes (T2D) is associated with early alterations in left ventricular (LV) diastolic function, which precedes the development of heart failure. These may be quantified by cardiac MRI feature tracking, which permits a direct assessment of myocardial relaxation through calculation of diastolic strain rates. Previous studies have not fully exploited this technique by integrating early and late LV diastolic relaxation in asymptomatic adults with T2D. Purpose To explore whether the peak early-to-late diastolic strain rate ratio (PEDSR:PLDSR), derived from cardiac MRI feature tracking, could: 1) identify diastolic dysfunction in an asymptomatic cohort of adults with T2D, 2) compare this technique with conventional echocardiographic measures of diastolic function. Methods Prospective cross-sectional study. People with T2D (n=253, mean age 63±7 years, 62% male, diabetes duration 11±8 years) without signs, symptoms or history of cardiovascular disease and non-diabetic controls (n=40, mean age 61±8 years, 63% male) underwent comprehensive phenotyping including echocardiography and cardiac MRI. The LV PEDSR:PLDSR was derived from cardiac MRI balanced steady-state free precession cine images using feature tracking. Correlations between circumferential PEDSR:PLDSR and echocardiography-derived E:A and E/e' were explored. Results Compared to controls, people with T2D had evidence of concentric LV remodelling, diastolic dysfunction, and diffuse myocardial fibrosis as demonstrated by increased LV mass/volume, E/e' ratio, and extracellular volume fraction, respectively (Table 1). People with T2D had lower PEDSR (0.87±0.23 vs 0.95±0.24 s–1, p=0.043), higher PLDSR (0.80±0.22 vs 0.67±0.16 s–1, p<0.001), and lower PEDSR:PLDSR ratio (1.18±0.46 vs 1.53±0.61, p<0.001). PEDSR:PLDSR was moderately correlated with E:A (r=0.495, p<0.001) (Figure 1) but not E/e' (r=0.087, p=0.182). Conclusions Compared to people without diabetes, lower PEDSR:PLDSR in asymptomatic subjects with T2D highlights impaired myocardial relaxation in early diastole and greater dependence on atrial contraction for LV filling in this group. This novel MRI measure may be promising tool to assess global diastolic function in people undergoing cardiac MRI and especially useful in those with poor echocardiographic windows. The functional and prognostic significance of PEDSR:PLDSR warrants further assessment in longitudinal studies. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): National Institute for Health Research (NIHR) United Kingdom through a Research Professorship award (RP-2017-08-ST2-007).British Heart Foundation through a Clinical Research Training Fellowship (FS/16/47/32190).