Elevated lipoprotein(a) and familial hypercholesterolemia in the coronary care unit: Between Scylla and Charybdis

BACKGROUND: Elevated lipoprotein(a) (Lp[a]) and familial hypercholesterolemia (FH) are inherited lipid disorders. Their frequencies, coexistence, and associations with premature coronary artery disease (CAD) in patients admitted to the coronary care unit (CCU) remain to be defined.

HYPOTHESIS: Elevated Lp(a) and FH are commonly encountered among CCU patients and independently associated with increased premature CAD risk.

METHODS: Plasma Lp(a) concentrations were measured in consecutive patients admitted to the CCU with an acute coronary syndrome (ACS) or prior history of CAD for 6.5 months. Elevated Lp(a) was defined as concentrations ≥0.5 g/L. Patients with LDL-C ≥ 5 mmol/L exhibited phenotypic FH. Premature CAD was diagnosed in those age < 60 years, and the relationship between this and elevated Lp(a) and FH was determined by logistic regression.

RESULTS: 316 patients were screened; 163 (51.6%) had premature CAD. Overall, elevated Lp(a) and FH were identified in 27.0% and 11.6% of patients, respectively. Both disorders were detected in 4.4% of individuals. Elevated Lp(a) (32.0% vs 22.2%; P = 0.019) and FH phenotype (15.5% vs 8.0%; P = 0.052) were more common with premature vs nonpremature CAD. Elevated Lp(a) alone conferred a 1.9-fold, FH alone a 3.2-fold, and the combination a 5.3-fold increased risk of premature CAD (P = 0.005).

CONCLUSIONS: Elevated Lp(a) and phenotypic FH were commonly encountered and more frequent with premature CAD. The combination of both disorders is especially associated with increased CAD risk. Patients admitted to the CCU with ACS or previously documented CAD should be routinely screened for elevated Lp(a) and FH.