Patients with diabetes mellitus experience significantly greater plaque progression, particularly regarding adverse plaque. Male sex and baseline plaque volume >75% were identified as independent risk factors for plaque progression; the latter actually tripled the risk.

This study with tomographic follow-up sought to determine the rate and extent of plaque progression, changes in plaque features, and clinical predictors of plaque progression in patients with diabetes.

A total of 1602 patients (age 61.3 ± 9.0 years; 60.3% men) assessed with coronary computed tomography angiography over a period of at least 24 months were enrolled in the PARADIGM (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging) trial.

Read also: Silent Diabetes Is the New Stealthy Enemy.

Study endpoints were changes in plaque features and plaque progression in diabetic patients compared with non-diabetic patients, as assessed by serial coronary computed tomography angiography. Plaque progression was defined as any plaque volume increase between baseline and follow-up.

As expected, diabetes was a risk factor for plaque progression (odds ratio [OR]: 1.526; 95% confidence interval [CI]: 1.100 to 2.118; p = 0.011). Changes in plaque volume and necrotic core volume were significantly greater in patients with diabetes.

Spotty calcification in nodules, positive remodeling, and burden of low-attenuation (soft) plaque were also more frequent in diabetic patients.

Read also: Does a Combination of Diabetes and Acute Coronary Syndrome Change the Revascularization Strategy?

Independent risk factors for plaque progression in patients with diabetes were male sex (OR: 1.4; p = 0.048) and plaque volume at baseline above 75% (OR: 3.1; p = 0.001).

The PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, published in the 2011 New England Journal of Medicine (NEJM) article A Prospective Natural-History Study of Coronary Atherosclerosis, had included patients with acute coronary syndromes and, after treating the culprit artery, assessed all vessels through intravascular ultrasound (IVUS), looking for clues that might predict which non-culprit vessel plaque might trigger future events. Results were similar in aspects such as plaque volume; however, PROSPECT researchers highlighted a combination of characteristics (plaque volume plus thin-cap fibroatheromas plus minimal luminal area >4.0 mm2).

We still have not found the correct risk characteristics so as to apply prophylaxis to functionally non-significant plaque, but clues abound.

Conclusion

Diabetic patients experience much greater plaque progression, which is particularly significant as regards adverse plaque. Male sex and, fundamentally, baseline plaque volume >75% were independent predictors of progression.

Original title: Natural History of Diabetic Coronary Atherosclerosis by Quantitative Measurement of Serial Coronary Computed Tomographic Angiography Results of the PARADIGM Study (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging).

Reference: Ung Kim et al. J Am Coll Cardiol Img 2018; online before print.

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