Microvascular dysfunction in patients with diabetes after cardioplegic arrest and cardiopulmonary bypass

Abstract

Purpose of the Review The purpose of current review is to describe the changes of microvascular function in diabetic patients after cardioplegic (CP) arrest and cardiopulmonary bypass (CPB) and cardiac surgery. Recent findings Cardiac surgery, especially that involving CP and CPB, is associated with significant changes in vascular reactivity of coronary/peripheral microcirculation, vascular permeability, gene/protein expression, and programmed cell death, as well as with increased morbidity and mortality after surgical procedures. In particular, these changes are more profound in patients with poorly controlled diabetes. Summary Since alterations in vasomotor regulation are critical aspects of mortality and morbidity of CP/CPB, a better understanding of diabetic regulation of microvascular function may lead to improve post-operative outcomes of diabetic patients after CP/CPB and cardiac surgery.

Enhanced coronary arteriolar contraction to vasopressin in patients with diabetes after cardiac surgery

“…Our group and others have extensively studied the effect of CP/CPB on microvascular reactivity, permeability, neurocognitive decline and other effects. 4–6, 7, 28–30 Most of the vascular effects result in a diminished response to vasoconstrictor agents such as phenylephrine, endothelin-1, and thromboxane-A 2 or endothelium-dependent vasodilator agonists such as substance P. 4–6, 8, 30 Two exceptions to this are the increased coronary contractile response observed to serotonin 10, 16 and now the response to vasopressin. The diminished contractile responses to many vasoconstrictors are due in large part to damage to the downstream contractile mechanism including mitogen activated protein kinase and protein kinase C 31 , altered relaxation mechanisms relate to increased oxidative stress, 32 oxygen derived free radicals, 33 neutrophil related mechanisms 34 and receptor desensitization.…”

“…1 In addition, patients with DM tend to suffer worse outcomes following cardiac surgery, 2 which may in part be related to vasomotor and endothelial dysfunction in arteries and arterioles. 3–8 The mechanism resulting in this microvascular dysfunction is not completely understood, but may be related to an altered response to vasopressin. 9–12…”

Impaired coronary contraction to phenylephrine after cardioplegic arrest in diabetic patients

“…21 It is believed that this impairment in patients with diabetes is due to increased PKC/NOX expression/activation, increased oxidative/nitrosative stress, enhanced myocardial apoptosis, and increased vascular permeability in the setting of CP/CPB and cardiac surgery. 9, 10, 25-27…”

Enhanced Activity by NKCC1 and Slc26a6 Mediates Acidic pH and Cl− Movement after Cardioplegia-Induced Arrest of db/db Diabetic Heart

“…Between 2012 and 2030, there is a projected 69% and 20% increase in the number of adults with diabetes in developing and developed countries, respectively [1]. These patients show worse clinical outcomes following cardiac surgeries as compared with patients without diabetes [3, 8–10]. During ischemia, the accumulation of cytosolic H + provides a greater driving force for the Na + -H + exchanger (NHE).…”