Left ventricular diastolic reserve in patients with type 2 diabetes mellitus

Abstract

Aims: Diastolic reserve is the ability of left ventricular filling pressures to remain normal with exercise. Impaired diastolic reserve may be an early sign of diabetic cardiomyopathy. We aimed to determine whether diastolic reserve differs in type 2 diabetes (DM) compared with non-DM, and to identify clinical, anthropological, metabolic and resting echocardiographic correlates of impaired diastolic reserve in patients with DM.

Methods and results: 237 patients (aged 53±11 years, 133 DM, ejection fraction 68±9%) underwent rest and exercise echocardiography. Mitral E and septal e' were measured at rest, immediately post, and 10 min into recovery. Analysis of covariance (ANCOVA) and binary regression with continuous outcomes were used to model e' and E/e' changes with exercise to identify impaired diastolic reserve defined as post-exercise E/e' ≥15. After adjusting for baseline differences, patients with DM immediately post-exercise had a lower septal e', a lower Δe' (1.2 vs 2.3 cm/s, p=0.006) and a higher Δ septal E/e' (1.7 vs 0.08, p<0.001) than patients without DM. In patients with normal resting E/e' of ≤8 (n=130), DM had a significantly higher post-exercise septal E/e' and a higher Δseptal E/e' (2.63 vs 0.50, p<0.001). E/e' in patients with DM remained significantly elevated up to 10 min post-exercise. Hypertension, longer duration of insulin therapy, poorer glycaemic control, worse renal function, larger left atrial volume and lower septal e' were independent correlates of impaired diastolic reserve in patients with DM.

Conclusions: Patients with DM have impaired diastolic reserve manifest as a blunted e' response with exercise, persisting into recovery. Clinical, anthropometric, metabolic and echocardiographic correlates of impaired diastolic reserve in patients with DM were identified. An impaired LV diastolic reserve may be the underlying pathophysiological mechanism in patients with DM with unexplained exertional dyspnoea and may allow earlier detection of DM cardiomyopathy.

Figure 1

Profile of diastolic function parameters at rest, immediately post-exercise and into recovery. (A) A significant elevation in septal E/e′ with exercise and into recovery in patients with diabetes mellitus (DM), while septal E/e′ remains normal for non-DM. (B) A similar pattern of rise and fall in mitral inflow E wave velocity with exercise in both groups. (C) An increase in septal e′ in both groups; however, this is significantly more for non-DM.

Figure 2

ROC curves for the three different BRCO models in predicting impaired diastolic reserve. The ROC curves for the ‘clinical model’ (solid line), ‘clinical and metabolic model’ (dashed line), and ‘clinical, metabolic and echocardiographic model’ (dotted line) are shown (AUC, area under the curve; BROC, Binary regression with continuous outcomes; ROC, Receiver operating characteristic).