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Levels of Lipoprotein(a) in cardiac transplant recipients
MISCELLANEOUS
Levels of Lipoprotein(a) in Cardiac Transplant Recipients C. Cristo´bal, L.A. Pulpo´n, J. Segovia, J.C. Gallego, and J. Toquero
H
IGH LEVELS OF lipoprotein(a) [Lp(a)] have been found to be a risk factor for the incidence of cardiovascular events in the general population.1–5 It is unknown whether there is a similar association in cardiac transplant recipients, i.e., a population with a high prevalence of dislipemia and cardiovascular events. There is one study6 in which investigators made determinations of Lp(a) levels in 130 transplant recipients and found that those levels were significantly higher in patients who had coronary disease than in those who had normal coronary arteries as shown by angiography. We have sought to assess the magnitude of Lp(a) levels in cardiac transplantation recipients, and to investigate its influence on the outcome of these patients.
METHODS Our study began in September 1994. It included 166 cardiac transplant recipients with a survival longer than 6 months after the procedure, and without clinical features that could suggest the presence of allograft coronary disease. Levels of Lp(a) were determined at the beginning of the study by enzyme-linked immunosorbent assay. Values of 30 mg/dL or less were considered normal; values more than 30 mg/dL were considered high. We divided the participants in two groups: Group A, with Lp(a) less than 30 mg/dL, made up of 108 patients; and group B, with Lp(a) more than 30 mg/dL, made up of 58 patients. Clinical and laboratory data were collected prospectively during an average period of more than 3 years. The end point of the study was to assess differences in global mortality between the two groups. Secondary end points were cardiovascular mortality, sudden death, and incidence of allograft coronary disease. In 30 patients, another determination of Lp(a) was made 6 months after the first, so that we could verify that there was a good correlation between both meditions (r ⫽ 0.90; P ⬍ .001).
RESULTS
Lp(a) was distributed among this population following a binomial curve, with a median value of 20.5 mg/dL, a range of 3 to 136 mg/dL, and an interquartilic range of 3 to 39 mg/dL. Sixty-five percent of the patients had normal values of Lp(a). Regarding baseline characteristics, the two groups differed significantly for average age (43 versus 48 years), weight (59 versus 69 kg), and prevalence of renal disfunction (14% versus 30%). We did not find significant differences in other variables such as hypertension, obesity, diabetes mellitus, smoking, medications used, and number of rejection episodes. Patients in group B had a higher prevalence of dislipemia (69% versus 44%; P ⬍ .002); and there was correlation between Lp(a) and total cholesterol (r ⫽ 0.21; P ⫽ .006), and triglycerides (r ⫽ 17; P ⫽ 0.04). A negative correlation with high density lipoprotein cholesterol levels was observed, but it did not have statistical significance. Patients who had ischemic cardiopathy before transplantation showed Lp(a) levels significantly higher than those with dilated cardiomyopathy (35 ⫾ 33.2 versus 22.6 ⫾ 20.6 mg/dL; P ⫽ .015). Three-year global mortality was not significantly different between both groups; nor were the curves of actuarial survival. There was an unexpected significant difference regarding cardiovascular mortality (group A: 12% versus group B: 3%), sudden death (A: 4% versus B: 0%),
From the Cardiac Transplantation Unit, Clı´nica Puerta de Hierro, Madrid, Spain. Address reprint requests to Dr Cristobal, C/Tutor No. 57, 2of, 28008 Madrid, Spain.
0041-1345/99/$–see front matter PII S0041-1345(99)00496-0
© 1999 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
2552
Transplantation Proceedings, 31, 2552–2553 (1999)
LIPOPROTEIN(A) IN HT PATIENTS
2553
allograft coronary disease (A: 13% versus B: 3%), and late nonspecific graft disfunction (A: 14% versus B: 3%).
REFERENCES
CONCLUSION
2. Rader D, Hoeg J, Brewer B: Ann Intern Med 120:1012, 1994
Lp(a) levels in cardiac transplant recipients show a correlation with lipid levels and other cardiovascular risk factors similar to the general population. Nevertheless, the influence of Lp(a) levels in the incidence of cardiovascular events does not seem to follow the pattern of the general population, but an inverse trend. Further studies are needed to confirm and explain these findings.
1. Dahlen G, Guyton J, Attar M, et al: Circulation 74:758, 1986
3. Schaefer E, Lamon-Fava S, Jenner J, et al: JAMA 271:999, 1994 4. Cantin B, Gagnon F, Moorjani S, et al: J Am Coll Cardiol 31:519, 1998 5. Bostom A, Cupples A, Jenner J, et al: JAMA 276:544, 1996 6. Barbir M, Kushwaha S, Hunt B, et al: Lancet 340:1500, 1992
Levels of Lipoprotein(a) in Cardiac Transplant Recipients C. Cristo´bal, L.A. Pulpo´n, J. Segovia, J.C. Gallego, and J. Toquero
H
IGH LEVELS OF lipoprotein(a) [Lp(a)] have been found to be a risk factor for the incidence of cardiovascular events in the general population.1–5 It is unknown whether there is a similar association in cardiac transplant recipients, i.e., a population with a high prevalence of dislipemia and cardiovascular events. There is one study6 in which investigators made determinations of Lp(a) levels in 130 transplant recipients and found that those levels were significantly higher in patients who had coronary disease than in those who had normal coronary arteries as shown by angiography. We have sought to assess the magnitude of Lp(a) levels in cardiac transplantation recipients, and to investigate its influence on the outcome of these patients.
METHODS Our study began in September 1994. It included 166 cardiac transplant recipients with a survival longer than 6 months after the procedure, and without clinical features that could suggest the presence of allograft coronary disease. Levels of Lp(a) were determined at the beginning of the study by enzyme-linked immunosorbent assay. Values of 30 mg/dL or less were considered normal; values more than 30 mg/dL were considered high. We divided the participants in two groups: Group A, with Lp(a) less than 30 mg/dL, made up of 108 patients; and group B, with Lp(a) more than 30 mg/dL, made up of 58 patients. Clinical and laboratory data were collected prospectively during an average period of more than 3 years. The end point of the study was to assess differences in global mortality between the two groups. Secondary end points were cardiovascular mortality, sudden death, and incidence of allograft coronary disease. In 30 patients, another determination of Lp(a) was made 6 months after the first, so that we could verify that there was a good correlation between both meditions (r ⫽ 0.90; P ⬍ .001).
RESULTS
Lp(a) was distributed among this population following a binomial curve, with a median value of 20.5 mg/dL, a range of 3 to 136 mg/dL, and an interquartilic range of 3 to 39 mg/dL. Sixty-five percent of the patients had normal values of Lp(a). Regarding baseline characteristics, the two groups differed significantly for average age (43 versus 48 years), weight (59 versus 69 kg), and prevalence of renal disfunction (14% versus 30%). We did not find significant differences in other variables such as hypertension, obesity, diabetes mellitus, smoking, medications used, and number of rejection episodes. Patients in group B had a higher prevalence of dislipemia (69% versus 44%; P ⬍ .002); and there was correlation between Lp(a) and total cholesterol (r ⫽ 0.21; P ⫽ .006), and triglycerides (r ⫽ 17; P ⫽ 0.04). A negative correlation with high density lipoprotein cholesterol levels was observed, but it did not have statistical significance. Patients who had ischemic cardiopathy before transplantation showed Lp(a) levels significantly higher than those with dilated cardiomyopathy (35 ⫾ 33.2 versus 22.6 ⫾ 20.6 mg/dL; P ⫽ .015). Three-year global mortality was not significantly different between both groups; nor were the curves of actuarial survival. There was an unexpected significant difference regarding cardiovascular mortality (group A: 12% versus group B: 3%), sudden death (A: 4% versus B: 0%),
From the Cardiac Transplantation Unit, Clı´nica Puerta de Hierro, Madrid, Spain. Address reprint requests to Dr Cristobal, C/Tutor No. 57, 2of, 28008 Madrid, Spain.
0041-1345/99/$–see front matter PII S0041-1345(99)00496-0
© 1999 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
2552
Transplantation Proceedings, 31, 2552–2553 (1999)
LIPOPROTEIN(A) IN HT PATIENTS
2553
allograft coronary disease (A: 13% versus B: 3%), and late nonspecific graft disfunction (A: 14% versus B: 3%).
REFERENCES
CONCLUSION
2. Rader D, Hoeg J, Brewer B: Ann Intern Med 120:1012, 1994
Lp(a) levels in cardiac transplant recipients show a correlation with lipid levels and other cardiovascular risk factors similar to the general population. Nevertheless, the influence of Lp(a) levels in the incidence of cardiovascular events does not seem to follow the pattern of the general population, but an inverse trend. Further studies are needed to confirm and explain these findings.
1. Dahlen G, Guyton J, Attar M, et al: Circulation 74:758, 1986
3. Schaefer E, Lamon-Fava S, Jenner J, et al: JAMA 271:999, 1994 4. Cantin B, Gagnon F, Moorjani S, et al: J Am Coll Cardiol 31:519, 1998 5. Bostom A, Cupples A, Jenner J, et al: JAMA 276:544, 1996 6. Barbir M, Kushwaha S, Hunt B, et al: Lancet 340:1500, 1992