Mitral valve surgery linked to improved glucose metabolism
MedWire News: Patients who undergo surgical intervention for mitral valve disease (MVD) may experience improvements in glucose metabolism and insulin resistance due to a reduction in atrial natriuretic peptide (ANP) and free fatty acid (FFA) levels, Italian researchers suggest.
"Therefore we hypothesize that the heart, under particular pathologic conditions... could become an active endocrine organ able to increase lipolysis and FFA levels influencing insulin sensitivity and glucose tolerance," say Lucilla Monti (San Raffaele Scientific Institute, Milan) and colleagues.
They add, however, that patients who undergo coronary artery bypass grafting (CABG) for coronary heart disease (CHD) do not experience similar improvements in glucose metabolism.
The team assessed pre- and post-surgery ANP, FFA, and insulin levels, and diabetes status in 50 patients with MVD who underwent mitral valve surgery, and 55patients with CHD who underwent CABG. These factors were also assessed in 166 matched healthy controls.
Prior to surgery, 56% and 67% of patients with MVD and CHD, respectively, had impaired glucose tolerance or diabetes newly diagnosed by oral glucose tolerance testing (OGTT), with the highest and lowest FFA and ANP levels found among MVD patients and healthy controls, respectively.
As reported in the Journal of Nutrition, Metabolism, & cardiovascular diseases, after surgery, the percentage of patients with impaired glucose tolerance or diabetes fell by 10% among MVD patients, but remained the same in CHD patients.
In addition, post-surgery fasting FFA and ANP levels fell by 33% and 55%, respectively, among MVD patients, while smaller decreases of approximately 15% and 20%, respectively, occurred among CHD patients.
Monti et al say that their findings "strongly suggest," although they do not demonstrate, a causal relationship between increased ANP, FFA, insulin resistance, and impaired glucose tolerance after OGTT in MVD. They conclude: "Future studies are needed to understand this important issue."
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By Lauretta Ihonor