Lipoprotein (a) in Chronic Renal Failure Patients Undergoing Hemodialysis: Does It Have an Independent Role in the Development of Further Cardiovascular Complications?

Luis Borque, Hospital ‘San Millán’, Central Laboratory, C/Autonomía 3, E-26004 Logroño, La Rioja (Spain) Dear Sir, Lipoprotein (a) [Lp(a)] has been pointed out as an independent risk factor associated with the development of atherosclerosis and cardiovascular disease, and much interest has been focused recently on the role of Lp(a) in this process. On the other side, cardiovascular disease is a frequent complication in chronic renal failure (CRF) patients treated with periodic maintenance hemodialysis. Some authors have previously described that Lp(a) values were higher in the whole group of CRF patients on hemodialysis treatment than in the healthy population [1]. We have seen the same effect in our CRF patients, and the aim of this paper is to look for some relationship between the increased lipidic parameters, especially Lp(a), and the presence or absence of a previous well-defined cardiovascular pathology in this subject group at risk. We have studied the lipidic profile of the census of 94 patients of our area without any excluding pathology undergoing long-term maintenance hemodialysis, measuring their serum triglycerides, cholesterol, HDL-cholesterol, apolipoprotein (apo)-A-I and apo-B and Lp(a). Following Attman [2], diabetic patients and patients under therapy with steroids or thyroid hormones were excluded. Then, patients were subdivided into two groups, according to the occurrence of cardiovascular complications. The cardiovascular complications evaluated were classified as congestive heart failure, hypertensive cardiopathy, ischemic cardiopathy, arrhythmia, and miscellaneous valvular pathology. All cardiovascular disorders were established by former clinical reports, periodic echocardiography, thorax radiographic images and electrocardiographic reports made routinely for these patients. 27 patients showed some cardiovascular disorder (CV + patients), and 67 did not (CV-patients). Samples were obtained as a matter of routine, prior to the hemodialysis session. Triglycerides, cholesterol and HDL-cholesterol analyses were performed on the fresh sera by routine methods, and frozen aliquots were stored up to 1 month for later determination of apo-A-I, apo-B and Lp(a). Serum triglycerides and cholesterol were measured on a Hitachi 717 analyzer, with manufacturer’s reagents and instructions (Boehringer Mannheim, Germany). HDL-cholesterol