Undiagnosed impaired glucose tolerance/diabetes mellitus and relationship with aortic stiffness in patients with acute coronary syndromes
Authors: Gargani L , Zywicki V , Bort I , Masini G , Morizzo C , Guarini G , Chiusolo S , Tamborrino P P , Vitale C , Caravelli P , Palagi C , Palombo C , De Caterina R 
Published: October 2024

Abstract

Background
Patients admitted with an acute coronary syndrome (ACS) often have unknown cardiovascular risk factors, such as impaired glucose tolerance (IGT) or diabetes mellitus (DM). Detecting these conditions is crucial to intensify appropriate therapies. Increased aortic stiffness, assessed by aortic pulse wave velocity (PWV), is associated with higher mortality in patients at high cardiovascular risk.

Purpose
Estimating the prevalence of IGT and DM and their relationship with increased aortic stiffness in patients admitted with an ACS.

Methods
Seventy-five consecutive patients admitted for ACS (21% women, mean age 63.6±11.1 ys), with fasting plasma glucose (PG) and glycated hemoglobin (HbA1c) not diagnostic for diabetes mellitus, underwent a fully standardized oral glucose tolerance test.
All patients were also evaluated with the Arteriograph device, which applies a brachial cuff-based oscillometric method for the estimation of aortic PWV and arterial pulse waveform features. The automated vascular studies and OGTTs were performed after patient stabilization, at least 96 hours after admission.

Results
Forty-one patients (55% of the total study population) showed an abnormal OGTT response: 14 patients had a 2-h PG-OGTT ≥ 200 mg/dL, uncovering a diagnosis of DM, and 27 patients had a 2-h PG-OGTT ≥ 140 mg/dL, uncovering a diagnosis of IGT. Patients with DM showed no differences in terms of age, cardiovascular risk factors, Framingham risk score, C-reactive protein values, whereas a significant difference was observed in the number of diseased coronary vessels (2.2±0.8 vs 1.6±0.9, p=0.016) and PWV values (10.0±1.3 vs 8.8±1.6 m/s, p=0.028). Similarly, when considering all patients with an abnormal OGTT, a significant difference was observed in PWV values compared to patients with a normal OGTT (9.5±1.5 vs 8.4±1.7 m/s, p=0.032), as well as in estimated glomerular filtration rate (78±18 vs 83±23 mL/min/1.73mq, p=0.05), and peak troponin values (3698±2905 vs 2124±2561 ng/ml, p=0.02).
At follow-up (mean time 51.7 months), no patients had died, but 5 patients had a new major cardiovascular event. Aortic pulse wave velocity values were different between patients with and without events (10.6±2.3 vs 8.6±1.4 m/s, p=0.024), and PWV was a significant predictor of events at univariate regression analysis (hazard ratio 1.93; 95 confidence intervals 1.01-3.69, p=0.047).

Conclusions
An unknown diagnosis of DM and/or IGT is very frequent in patients with ACS. Undiagnosed dysglycemic conditions are linked to a higher prevalence of coronary multivessel disease and increased aortic stiffness, which is also predictive of future cardiovascular events. A systematic screening with OGTT may help identifying patients at even higher cardiovascular risk, and tailoring secondary prevention strategies through personalized aggressive therapeutic interventions.