Early detection of left ventricular dysfunction in first-degree relatives of diabetic patients by myocardial deformation imaging: The role of endothelial glycocalyx damage

Abstract

Background

First-degree relatives of type-2 diabetes patients (FDR) present insulin resistance. We investigated whether FDR and dysglycaemic subjects demonstrate abnormal endothelial glycocalyx and LV deformation during postprandial hyperglycemia.

Methods

We studied 40 FDR with normal oral glucose test (OGTT), 40 subjects with abnormal OGTT (dysglycaemic) and 20 subjects with normal OGTT without parental history of diabetes (normoglycaemic). At 0 and 120 min of OGTT we measured: a) LV longitudinal strain (LS) of subendocardial, mid-myocardial and subepicardial layers, global LS (GLS), peak twisting (pTw), untwisting velocity (pUtwVel), by speckle tracking echocardiography b) perfused boundary region (PBR) of the sublingual arterial microvessels; high PBR values represent reduced glycocalyx thickness. Insulin resistance was evaluated using insulin sensitivity index (ISI).

Results

ISI was related with baseline PBR, GLS and pTw in all subjects (p < 0.05). Compared to normoglycaemics, FDR and dysglycaemics had higher PBR, lower ISI, GLS (−18.4 ± 2.6 and −16.8 ± 2.0 vs. −19.2 ± 2.4%), subendocardial LS (−19.0 ± 4.2 and −17.9 ± 3.0 vs. −20.1 ± 3.4%), pTw (14.4 ± 4.4 and 15.6 ± 6.4 vs. 16.9 ± 6.5 deg) and pUtwVel (p < 0.05 for all comparisons). A GLS < −18% identified FDR with LV dysfunction (p = 0.016).
Post-OGTT, GLS and the subendocardial LS decreased while pTw and pUtwVel increased in FDR and dysglycaemics (p < 0.05) indicating prevalence of the motion of the subepicardial over a dysfunctioning subendocardial myocardial helix. Increased PBR was related with impaired deformation markers at baseline and 120 min of OGTT (p < 0.05).

Conclusion

First-degree relatives and dysglycaemics have reduced glycocalyx thickness related with impaired LV longitudinal, twisting-untwisting function. Postprandial hyperglycemia when combined with insulin resistance causes LV longitudinal dysfunction leading to increased LV twisting.