Impact of renal function on mean platelet volume and its relationship with coronary artery disease: A single-centre cohort study

Background Mean platelet volume (MPV) has been proposed as a marker of platelet reactivity and cardiovascular disease. Chronic kidney disease (CKD) significantly favors the occurrence of cardiovascular events, by increasing the circulating levels of a wide spectrum of pro-oxidant and pro-thrombotic mediators. However, opposite alterations of platelet function, both enhanced aggregability and increased bleeding diathesis have been reported in these patients, with contrasting results on the effects of renal function on MPV and coronary artery disease, that were assessed in present study. Methods In patients undergoing coronary angiography, MPV and renal function (serum creatinine and estimated Glomerular Filtration Rate, eGFR, by MDRD formula) were assessed at admission. Coronary artery disease (CAD) was defined as a stenosis > 50% in at least 1 coronary vessel, while severe CAD as left main or trivessel disease. Results Among 3712 patients, 1044 (28.1%) had chronic kidney disease. CKD was related with age, female gender, diabetes and glycemic control, history of myocardial infarction, cerebrovascular accidents, coronary artery bypass grafting and left ventricular dysfunction or arrhythmias as indication to angiography, therapy with angiotensin-receptor blockers, nitrates, diuretics and calcium-antagonists, but lower rate of smoking, lower fibrinogen levels, haemoglobin, total and HDL cholesterol (p < 0.001, respectively). CKD patients displayed increased severity and complexity of CAD (p < 0.001) and significantly larger platelet volume (p < 0.001), with CKD resulting as independent predictor of MPV above the median (≥ 10.85 fl; Adjusted OR[95%CI] = 1.56[1.23,1.99], p = 0.002). Moreover, in the 1044 patients with renal failure, higher platelet volume (above the median value; ≥ 10.85 fl) was associated with age (p = 0.05), haemoglobin levels and platelet count (p < 0.001), but not to a higher prevalence or extent of coronary artery disease (CAD: Adjusted OR[95%CI] = 0.80[0.58-1.09], p = 0.16; severe CAD, adjusted OR[95%CI] = 1.07[0.81-1.41], p = 0.65). Conclusions Higher values of MPV are observed among patients with chronic kidney disease, inversely relating to eGFR. However, larger platelet size does not contribute to explain the increased severity of coronary artery disease observed among these patients.