Diabetes is a major risk factor for cardiovascular disease. But the disease path leading to heart attack is not the same for all people with type 2 diabetes. Two different groups of patients with type 2 diabetes, who develop two different types of ischemic heart disease over the years, were identified. Rocco Antonio Montone, medical director at the Cardiological Intensive Care Unit of the Agostino Gemelli Irccs University Polyclinic Foundation and PhD in cardiology at the Catholic University, and Dario Pitocco, Uo Director of Diabetology of the Foundation and associate professor of Endocrinology at the Cattolica.
What makes the difference – reports a note from Gemelli – is the presence or absence of microvascular complications. Parameter that could allow to stratify the diabetic population before the onset of a heart attack, and therefore guide the doctor to the best preventive therapy, in a personalized way. It is the first time that these two large populations of people with type 2 diabetes have been distinguished, who develop two different types of atherosclerosis: one more widespread and stable, the other more ‘acute’. The research has just been published in Cardiovascular Diabetology.
“Analyzing the results of coronary angiography, integrated with study Oct (Optical coherence tomography) – says Montone – we have highlighted two different types of patients in the diabetic population: those who have a single large ‘soft’ atherosclerotic plaque, that is, rich in lipids and therefore ready to rupture (at the base of the most severe heart attacks in the 50-60 years age group) and those who have extensive calcifications and many small ‘healed’ plaques, spread throughout the coronary tree, which give chronic anginal symptoms, rather than a severe acute heart attack “.
“The patients of the first group – explains Pitocco – are generally younger, obese, dyslipidemic and with a diabetes characterized above all by insulin resistance, rather than by deficiency. In the other group we find patients generally older, thin, with a pancreas that has exhausted its function and need insulin therapy. Analyzing the presence or absence of microvascular complications, we have highlighted the presence of a correlation between diabetic microvascular complications and type of atherosclerosis and cardiovascular events at follow up “.
The study involved 320 diabetic patients (mean age 70 years) with ischemic heart disease, at their first coronary event and undergoing coronary angiography; In a subgroup of patients, the OCT was also used, a microscope that allows you to see the details of the coronary wall ‘from inside’. The patients were divided into different groups according to the presence or absence of microvascular complications (diabetic retinopathy, nephropathy and neuropathy). All were followed up over time to record the occurrence of further major cardiovascular events (Mace).
Patients with diabetic microvascular complications – again the note – tend to present ischemic heart disease characterized by many calcifications and by the so-called ‘healed’ plaques (a sort of ‘scar’ that is indicative of a heart attack that was about to occur, but never occurred). Conversely, individuals without microvascular complications tend to have ischemic heart disease characterized by large lipid atherosclerotic plaques. At the follow-up, the group of patients with microcalfications presented a greater number of Mace, thus configuring a population with ischemic heart disease more susceptible to repeated hospitalizations.
“Within the group of people with type 2 diabetes – underlines Pitocco – there are two large groups of patients: those with insulin resistance and those with insulin deficiency. Also from the point of view of vascular complications, we distinguish patients who develop microvascular complications, i.e. affecting the small arterial vessels (retinopathy which can lead to severe damage to sight, nephropathy which can lead to renal failure, diabetic neuropathy which can favor foot injuries, autonomic neuropathy) and others that do not have this type of complication. Both groups can present coronary complications, but with different mechanisms, starting with the composition of the atherosclerotic plaque “.
“Calcification – continues Pitocco – is also a characteristic process of diabetic peripheral neuropathy; and with our study we have shown that, at the coronary level, patients with microangiopathic complications have a different plaque composition compared to diabetics without microangiopathic complications. Perhaps the presence of calcifications is linked to microangiopathy and insulin, that is to the fibrosing capacity of insulin (the smooth muscle cells of the vessels are transformed into osteoblastic-like cells, capable of depositing calcium on the vessel walls). These same patients from the point of view of their metabolic phenotype have a lack of insulin secretion and therefore require insulin-based therapy “.
“Personalized medicine – concludes Filippo Crea, director of the Department of Cardiovascular and Pneumological Sciences, Agostino Gemelli Irccs University Polyclinic Foundation and full professor of Cardiology at the Catholic University – is the final goal towards which modern medicine tends. This is already clinical reality for diseases characterized by a single genetic alteration. For complex diseases, such as ischemic heart disease and diabetes, caused by the interaction between polygenic alterations and environmental risk factors, a first intermediate approach is personalized medicine. This means that patients with the same clinical manifestation, for example diabetes or ischemic heart disease, are divided into homogeneous groups that have a similar disease mechanism. The study published by Montone and Pitocco clearly demonstrates that among patients with diabetes and ischemic heart disease it is possible to identify two subgroups with different disease mechanisms that require different therapies: this is stratified medicine ”.