Variability of lipoprotein(a) concentrations in a cohort of patients enrolled in a cardiac rehabilitation program after an acute coronary syndrome

Abstract Introduction Lipoprotein (a), Lp(a), is a low-density lipoprotein cholesterol-like particle bound to apolipoprotein(a), linked with increased cardiovascular risk. According to the evidence, Lp(a) is mainly determined by genetic variability of the gene of apo(a). There are few factors that might modify the Lp(a) concentration such as ethnicity, sex, chronic kidney or liver disease or inflammation. Therefore, it is recommended to assess its concentration once in a lifetime with few exceptions (such as kidney disease). In the setting of secondary prevention after a myocardial infarction, there is no clear recommendation when to evaluate it. Purpose The aim of the study is to evaluate the changes in concentration of Lp(a) depending on the moment of extraction following an acute coronary syndrome (ACS) in order to determine the best moment to evaluate this lipoprotein. Methods The study is a single-center, observational, descriptive cohort study. Out of a cohort of 344 patients included in the cardiac rehabilitation program of our hospital between December 2022 and October 2023, we found 84 with two determinations of Lp(a) levels. The first one upon admission for ACS and the second one at the first visit in cardiac rehabilitation (three to four weeks from hospital discharge). After, we conducted another determination in 27 patients (32.1%) during an outpatient clinic visit months after the event. Results Regarding the baseline characteristics of our sample of 84 patients, the mean age was 59.7 ± 1.2 years and 21.3% were women. Hypertension was present in 52.5% of patients, dyslipidemia in 53.8%, diabetes in 22.5%, obesity in 27.5%, active smoking in 57.5% and active drinking in 12.5%. In the primary events setting 49.4% suffered an ST segment elevation myocardial infarction (STEMI) and 42.5% a NSTEMI. Out of 84 patients, 48.4% had preserved left ventricular systolic function and none had aortic stenosis. The third measurement of lipoprotein(a) was obtained at an average of 12.9 ± 1.1 months. There were statistically significant differences between the first Lp(a) levels and the second ones (Wilcoxon p = 0,000) and also between the Lp(a) levels during the first cardiac rehabilitation visit and the ones done 12 months after the event (Wilcoxon p = 0,009). Nevertheless, we did not find significant differences between the first and the third determination (Wilcoxon p = 0,269). Between the first and the second determination there was a mean percentage change of 44.4 ± 15.4 % and between the second and the third one there was a mean percentage change of 11.9 ±4.4%. Conclusions While Lp(a) measurement is generally considered stable throughout life, our results indicate that in the early post-ACS phase, Lp(a) levels may not reflect a patient's long-term baseline values. Further research is needed to determine the clinical relevance of these variations and to establish the most appropriate timing for Lp(a) measurement in secondary prevention.Bland Altman admission to cardiac rehab Bland Altman admission to one year