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Apolipoprotein (a) concentrations and susceptibility to coronary artery disease in patients with peripheral vascular
Insights
Elevated apolipoprotein(a) levels are associated with coronary artery disease severity in patients with peripheral vascular disease. This suggests apolipoprotein(a) may aid risk assessment in these patients.
Area of Science:
- Cardiovascular Medicine
- Clinical Chemistry
Background:
- Atheromatous peripheral vascular disease (PVD) often coexists with coronary artery disease (CAD).
- Apolipoprotein(a) [apo(a)] is a component of low-density lipoprotein (LDL) and its concentrations are known to be heritable.
- The relationship between apo(a) levels and CAD in patients with PVD requires further investigation.
Purpose of the Study:
- To examine the association between apolipoprotein(a) concentrations and the presence and severity of angiographically defined coronary artery disease.
- To determine if apo(a) levels can serve as a risk factor for CAD in patients with atheromatous peripheral vascular disease.
Main Methods:
- 40 patients undergoing peripheral vascular surgery were assessed clinically and via coronary arteriography.
- Apolipoprotein(a) concentrations were measured using an immunoradiometric assay.
- Coronary artery disease severity was categorized based on arteriographic findings.
Main Results:
- Apolipoprotein(a) concentrations significantly increased with the severity of coronary artery disease (p < 0.005).
- Patients with apo(a) levels above the cohort median (206 U/L) had a 7.4-fold increased prevalence of CAD (p < 0.01).
- Standard lipid profiles and peripheral vascular disease distribution were similar across CAD severity groups.
Conclusions:
- An association exists between apolipoprotein(a) concentrations and angiographically defined coronary artery disease in patients with large vessel peripheral vascular disease.
- These findings suggest potential differences in the pathogenesis of coronary and peripheral atheroma.
- Measurement of apolipoprotein(a) may enhance risk factor assessment for patients undergoing peripheral vascular surgery.
Objective:
To investigate the relation between apolipoprotein(a) concentrations and angiographically defined coronary artery disease in patients with atheromatous peripheral vascular disease.
Design:
40 consecutive patients were recruited at the time of admission for peripheral vascular surgery. All underwent clinical assessment and coronary arteriography. Apolipoprotein(a) concentrations were measured by an immunoradiometric assay.
Setting:
Tertiary referral centre.
Subjects:
Patients requiring surgical intervention for large vessel peripheral vascular disease.
Main Outcome Measures:
Presence or absence and severity and distribution of angiographically defined coronary artery disease. Measurement of circulating contractions of apolipoprotein(a) and other lipid indices.
Results:
Coronary artery disease was absent in 11 patients (group 1), mild to moderate in 12 (group 2), and severe in 17 (group 3). The distribution of peripheral vascular disease and of standard lipid indices was similar in these three groups of patients. There was a significant difference in apolipoprotein(a) concentrations between the three groups, with concentrations progressively increasing with the severity of coronary artery disease (mean (95% confidence interval): group 1, 112 U/1 (52 to 242); group 2, 214 U/1 (129 to 355); group 3, 537 U/1 (271 to 1064) (analysis of variance p < 0.005). The prevalence of coronary artery disease was increased 7.4 fold in patients with apolipoprotein(a) concentrations that were greater than the cohort median (206 U/1) (p < 0.01).
Conclusions:
The results show an association between apolipoprotein(a) concentrations and angiographically defined coronary artery disease in patients with large vessel peripheral vascular disease. The findings imply differences in the pathogenesis of coronary and peripheral atheroma and suggest that the measurement of apolipoprotein(a) may prove a useful additional tool in the risk factor assessment of patients undergoing peripheral vascular surgery.