High serum concentration of lipoprotein(a) is a risk factor for restenosis after percutaneous transluminal coronary angioplasty in Japanese patients with single-vessel disease

Prediction of Short-Term Progression or Regression of Atherosclerotic Coronary Artery Disease by Lipoprotein (a): A Quantitative Coronary Angiographic Study

This study assessed whether progression of coronary artery atherosclerotic lesions could be predicted in the short term using various lipid profiles. In 37 patients (61.9 ±9.5 years) under going coronary angioplasty and with 6-month follow-up angiography, quantitative coronary angiography of a new or changed lesion was performed in the follow-up examination, except for intervention vessels. The progression-regression score of the assessed lesion was calcu lated as the baseline minus the follow-up minimal lumen diameter. The serum lipoprotein (a) level was higher in the progression group (progression-regression score >0.15 mm), than in the regression group (≤ -0.15 mm; p<0.01) and the no change group (within ±0.15 mm; p < 0.05). Remnant-like lipoprotein particle-cholesterol and apolipoprotein-B levels were also higher in the progression group. However, multiple regression analysis of the progression showed that the progression-regression score was independently correlated with lipoprotein (a) alone (R = 0.50, p < 0.05). This shows that lipoprotein (a) is an independent predictor of coronary atherosclerotic lesion progression over the short term.

Lipoprotein(a), interleukin-10, C-reactive protein, and 8-year outcome after percutaneous coronary intervention

BACKGROUND

This prospective study investigated the association between preprocedural biomarker levels and incident major adverse cardiac events (MACE) in complex patients undergoing percutaneous coronary intervention (PCI) with sirolimus-eluting stenting.

HYPOTHESIS

Lipoprotein(a) (Lp[a]), interleukin-10 (IL-10), and high-sensitivity C-reactive protein (CRP) have long-term prognostic value in patients undergoing PCI.

METHODS

Between April 2002 and February 2003, 161 patients were included in the study. Blood was drawn before the procedure, and biomarkers were measured. Patients were followed-up for MACE (death, nonfatal myocardial infarction, and repeat revascularization). Cox proportional hazard models were used to determine risk of MACE for tertiles of biomarkers. Both 1-year and long-term follow-up (median, 6 years; maximum, 8 years) were evaluated.

RESULTS

Mean age was 59 years, and 68% were men. During long-term follow-up, 72 MACE occurred (overall crude cumulative incidence: 45% [95% confidence interval (CI): 37%-52%]). Lp(a) was associated with a higher 1-year risk of MACE, with an adjusted hazard ratio (HR) of 3.1 (95% CI: 1.1-8.6) for the highest vs the lowest tertile. This association weakened and lost significance with long-term follow-up. IL-10 showed a tendency toward an association with MACE. The 1-year HR was 2.1 (95% CI: 0.92-5.0). Long-term follow-up rendered a similar result. The association of CRP with MACE did not reach statistical significance at 1-year follow-up. However, CRP was associated with long-term risk of MACE, with an HR of 1.9 (95% CI: 1.0-3.5).

CONCLUSIONS

In this prospective study, preprocedural Lp(a) level was associated with short-term prognosis after PCI. The preprocedural CRP level was associated with long-term prognosis after PCI.

Serum lipoprotein(a) level and clinical coronary stenosis progression in patients with myocardial infarction: re-revascularization rate is high in patients with high-Lp(a)

BACKGROUND

High serum lipoprotein(a) (Lp(a)) levels are associated with coronary artery disease.

METHODS AND RESULTS

The serum Lp(a) levels of 130 patients with acute myocardial infarction (AMI) who underwent direct percutaneous coronary intervention were investigated. On the basis of Lp(a) level at 1 month after the onset of AMI, the patients were classified into 2 groups (high-Lp(a) (> or =30 mg/dl) and low-Lp(a) (< 30 mg/dl)) for evaluation of the clinical coronary stenosis progression (CCSP) rate. CCSP is defined as either target lesion revascularization (TLR) or new lesion revascularization (NLR). The CCSP rate was significantly higher in the high-Lp(a) group than in the low-Lp(a) group (65.8% vs 29.3%, p<0.01). In patients who had coronary stents in the acute phase (n=79), the CCSP and NLR rates were significantly higher in the high-Lp(a) group than in the low-Lp(a) group (45.0% vs 20.3%, p<0.05; 35.0% vs 6.8%, p<0.01), but there was no significant difference in TLR rate between the 2 groups (10.0% vs 13.6%, p=0.858).

CONCLUSIONS

High serum Lp(a) level is a significant risk factor for CCSP, but does not influence restenosis after stenting.

Association Between Plasma Lipoprotein(a) Concentration and Restenosis After Stent Implantation

BACKGROUND

The plasma concentration of lipoprotein (a) [Lp(a)] is associated with atherosclerotic and thrombotic vascular diseases. The aim of the present study was to evaluate the association between plasma Lp(a) concentration and in-stent restenosis.

METHODS AND RESULTS

One hundred and 9 patients with successful elective coronary stent implantation underwent follow-up angiography at 24+/-6 weeks. Restenosis after stent implantation occurred in 38 patients. Univariate analysis showed that the reference diameter of the lesion was smaller in the restenosis group (2.93+/-0.29 mm) than in the no-restenosis group (3.21+/-0.43 mm) (p < 0.05). The lesion was longer in the restenosis group (14.2+/-5.3 mm) than in the no-restenosis group (11.6+/-4.9 mm) (p < 0.05). Plasma Lp(a) concentrations in the restenosis group (30.5+/-23.9 mg/dl) were higher than in the no-restenosis group (16.9+/-11.1 mg/dl) (p < 0.01). Other lipid concentrations were similar in both groups. Among the plasma Lp(a) concentrations, the rate of restenosis (71.4%) in the high Lp(a) group (> 40 mg/dl) (n = 14) was greater compared with the other groups: 33.3% in the intermediate Lp(a) group (10-40 mg/dl) (n = 54), and 24.4% in the low Lp(a) group (< 10 mg/dl) (n = 41) (p < 0.01). The late loss (0.57+/-0.53 mm) in the low Lp(a) group was significantly less than the other groups: 0.88+/-0.47 mm in the intermediate Lp(a) group, and 1.08+/-0.56 mm in the high Lp(a) group (p < 0.05). In a multivariate regression model, plasma Lp(a) concentration remained significant as an independent predictor of restenosis in patients undergoing stent implantation (p = 0.020 odds ratio (OR) 1.37 95%conficence interval (CI) 1.050-1.793), although the reference diameter (p = 0.025 OR 0.23 95%CI 0.061-0.830) and lesion length (p = 0.021 OR 1.12 95%CI 1.017-1.232) were related to stent restenosis.

CONCLUSIONS

Plasma Lp(a) concentration is an independent predictor of stent restenosis.

Lipoprotein(a) as a risk factor for atherosclerosis and thrombosis: mechanistic insights from animal models

Evidence continues to accumulate from epidemiological studies that elevated plasma concentrations of lipoprotein(a) [Lp(a)] are a risk factor for a variety of atherosclerotic and thrombotic disorders. Lp(a) is a unique lipoprotein particle consisting of a moiety identical to low-density lipoprotein to which the glycoprotein apolipoprotein(a) [apo(a)] that is homologous to plasminogen is covalently attached. These features have suggested that Lp(a) may contribute to both proatherogenic and prothrombotic/antifibrinolytic processes and in vitro studies have identified many such candidate mechanisms. Despite intensive research, however, definition of the molecular mechanisms underlying the epidemiological data has proven elusive. Moreover, an effective and well-tolerated regimen to lower Lp(a) levels has yet to be developed. The use of animal models holds great promise for resolving these questions. Establishment of animal models for Lp(a) has been hampered by the absence of this lipoprotein from common small laboratory animals. Transgenic mice and rabbits expressing human apo(a) have been developed and these have been used to: (i) examine regulation of apo(a) gene expression; (ii) study the mechanism and molecular determinants of Lp(a) assembly from LDL and apo(a); (iii) demonstrate that apo(a)/Lp(a) are indeed proatherogenic and antifibrinolytic; and (iv) identify structural domains in apo(a) that mediate its pathogenic effects. The recent construction of transgenic apo(a) rabbits is a particularly promising development in view of the excellent utility of the rabbit as a model of advanced atherosclerosis.

Lipoprotein(a): an emerging cardiovascular risk factor

Lipoprotein(a) is a cholesterol-enriched lipoprotein, consisting of a covalent linkage joining the unique and highly polymorphic apolipoprotein(a) to apolipoprotein B100, the main protein moiety of low-density lipoproteins. Although the concentration of lipoprotein(a) in humans is mostly genetically determined, acquired disorders might influence synthesis and catabolism of the particle. Raised concentration of lipoprotein(a) has been acknowledged as a leading inherited risk factor for both premature and advanced atherosclerosis at different vascular sites. The strong structural homologies with plasminogen and low-density lipoproteins suggest that lipoprotein(a) might represent the ideal bridge between the fields of atherosclerosis and thrombosis in the pathogenesis of vascular occlusive disorders. Unfortunately, the exact mechanisms by which lipoprotein(a) promotes, accelerates, and complicates atherosclerosis are only partially understood. In some clinical settings, such as in patients at exceptionally low risk for cardiovascular disease, the potential regenerative and antineoplastic properties of lipoprotein(a) might paradoxically counterbalance its athero-thrombogenicity, as attested by the compatibility between raised plasma lipoprotein(a) levels and longevity.

Is lipoprotein(a) a predictor for survival in patients with established coronary artery disease? Results from a prospective patient cohort study in northern Sweden

OBJECTIVES

Lipoprotein(a) [Lp(a)] is a known risk factor for the development of atherosclerosis. The aim of the present study was to test the importance of Lp(a) as a predictor for the further prognosis in patients with established coronary artery disease.

DESIGN

A prospective patient cohort study was carried out.

SETTING AND SUBJECTS

The cohort consists of 1216 patients who were examined with coronary angiography at the University Hospital in Umeå, Sweden, because of stable effort angina.

MAIN OUTCOME MEASURES

Lipids, Lp(a), fibrinogen, antithrombin III (AT III), sedimentation rate and clinical data were registered at angiography. After a mean follow-up time of 6.7 years information on survival was collected from the municipal census lists and death certificates were examined. Total mortality and mortality because of cardiovascular disease were both used as outcome variables in the survival analyses. RESULTS. The total mortality in the patient cohort was 16.4%. An Lp(a) level of 300 mg L-1 or more was found in 30% of the study population and was found to be an independent predictor for death. A high fibrinogen, a low AT III level, a depressed left ventricular function and a high coronary obstruction score were other significant independent predictors of death. Total cholesterol, HDL- and LDL-cholesterol were not related to survival in this study, but a substantial proportion of the population probably received lipid-lowering agents during the study period.

CONCLUSIONS

An Lp(a) level exceeding 300 mg L-1 indicates a poor further prognosis and may help to identify patients who probably need powerful secondary prevention programmes to improve their prognosis.

Serum lipids, lipoprotein(a) level, and apolipoprotein(a) isoforms as prognostic markers in patients with coronary heart disease

OBJECTIVE

Our objective was to study prognostic factors for death in patients with coronary heart disease (CHD), focusing on serum lipids and lipoproteins.

DESIGN AND SUBJECTS

The study subjects were 964 patients with angina pectoris who underwent coronary angiography between 1985 and 1987. Follow-up, including survival and cause of death, was carried out in April 1998.

RESULTS

A total of 363 patients died. Increasing age, diabetes and low levels of HDL cholesterol and of apolipoprotein (apo) AI were associated with increased risk of total mortality and cardiac mortality. In men, low levels of LDL cholesterol and of apoB were associated with increased risk of death, but not of cardiac death only; high levels of lipoprotein(a) [Lp(a)] were not associated with increased risk. In women, however, there was a trend towards increased risk with increasing Lp(a) levels (P = 0.054); the smallest isoform of apo(a) was associated with a twofold increase in risk. In women, but not in men, risk decreased with increasing molecular weight of the apo(a) isoforms.

CONCLUSIONS

Amongst lipoprotein variables, low levels of HDL cholesterol and of apoAI and the presence of low-molecular weight isoforms of apo(a) are associated with increased risk of death in patients with CHD. Apo(a) isoforms and Lp(a) levels seem to be more important as risk factors amongst women. Low LDL cholesterol and apoB levels were associated with increased risk, but only in men. These findings demonstrate the importance of a gender-specific analysis of risk factors for CHD.

Predictors of restenosis after coronary angioplasty. A study on demographic and metabolic variables

OBJECTIVE

The major concern about percutaneous transluminal coronary angioplasty (PTCA) is the high incidence of restenosis.

METHODS

Demographic, clinical and biochemical data were recorded 2 weeks prior to PTCA in 388 patients fulfilling the criteria for initial stenosis, successful PTCA, and angiographic follow-up after 6 months. Restenosis was evaluated by quantitative coronary angiography.

RESULTS

Variables predictive of restenosis in univariate analysis were diabetes mellitus, male gender, and the levels of high density lipoprotein (HDL) cholesterol, apolipoprotein A1 (Apo A1) and thio-barbituric acid-reactive substances (TBARS). In trend analysis through quartiles TBARS and fasting glucose levels were significantly associated with restenosis (p = 0.016 and 0.044, respectively), whereas the negative predictivity of Apo A1 and HDL-cholesterol were of borderline significance. In multivariate analysis male gender and diabetes mellitus showed predictivity of significance, and a negative predictivity was also apparent for HDL-cholesterol.

CONCLUSION

We conclude that diabetes mellitus, male gender, and low HDL-cholesterol are predictors of restenosis 6 months after PTCA. In addition, TBARS may be a marker for the development of restenosis after PTCA.

Lipoprotein (a) and anticardiolipin antibodies are risk factors for clinically relevant restenosis after elective balloon percutaneous transluminal coronary angioplasty

Recent reports have shown the importance of new risk factors for cardiovascular disease. We investigated the relationship between Lp(a), fibrinolytic parameters and anticardiolipin antibodies (aCL) and the occurrence of clinical recurrence owing to restenosis after elective balloon percutaneous transluminal coronary angioplasty (PTCA) without stenting. In 167 patients, undergoing PTCA, Lp(a) plasma levels, aCL, euglobulin lysis time (ELT), plasminogen activator inhibitor-1 (PAI-1) activity and tissue-type plasminogen activator (t-PA) plasma levels were evaluated before the procedure. During follow-up 29 patients underwent clinical recurrence due to restenosis. Lp(a) levels were significantly higher in patients with restenosis in comparison to those without (P<0.05); an earlier restenosis was observed in patients with Lp(a) values >450 mg/L. Kaplan-Meier survival estimate showed an earlier occurrence of restenosis in patients with base-line Lp(a)>300 mg/l associated with aCL positivity. High Lp(a) plasma levels play a role in the occurrence of clinical recurrence due to restenosis after elective balloon PTCA without stenting; the association with aCL accelerates the development of restenosis.

Absence of relationship between plasma Lp(a), Lp-AI, anti-oxidized LDL autoantibodies, LDL immune complexes concentrations and restenosis after percutaneous transluminal coronary angioplasty

To determine the relation between the concentration of Lp(a), LpAI, immunological markers of LDL oxidation (antioxidized-LDL autoantibodies (LDL-AB), LDL immune complexes (LDL-IC)) and restenosis after percutaneous transluminal coronary angioplasty (PTCA) in a Caucasian population (France), we studied 77 consecutive patients who successfully underwent PTCA. All were evaluated by follow-up angiography at an average of 6 months after PTCA and were divided into two groups: existence of restenosis (32 patients, group (G+)) and absence of restenosis (45 patients, negative group (G-)). The prevalence of diabetes mellitus was higher in the restenosis positive group than in the negative group (28% versus 2% respectively, P=0.001). Before and after adjustment in diabetes mellitus frequency there was no difference in the usual lipid parameters (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, phospholipids, apolipoprotein AI, apolipoprotein B) between the two groups of patients nor in the other parameters (Before adjustment: Lp(a): 0.306+/-0.352 g/l (G+) vs. 0.263+/-0.270 g/l (G-); LpAI: 0.414+/-0.126 g/l (G+) vs. 0.390+/-0.092 g/l (G-); LDL-AB: arbitrary unit (AU) 3.75+/-1.91 (G+) vs. 3.67+/-1.24 (G-); LDL-IC: (AU) 0.93+/-0.82 (G+) vs. 0.86+/-0.44 (G-)). Spearman correlation coefficients did not report any correlation between late loss, loss index, gain and the above mentioned plasma parameters. In conclusion, usual tested plasma lipids, Lp(a), LpAI and in vivo markers of LDL oxidation (LDL-AB and LDL-IC) are not risk factors for restenosis after PTCA in this French population.

Plasmin activation system in restenosis: role in pathogenesis and clinical prediction?

During recent years it has become increasingly recognized that the plasmin activation system is involved in the development of atherosclerosis and restenosis. Responsible pathophysiologic mechanisms, however, remain elusive. This review focuses primarily on the clinicians, point of view, suggesting that increases in plasminogen activator inhibitor type-1 (PAI-1) plasma levels after balloon angioplasty or permanently elevated lipoprotein (a) (Lp(a)) plasma levels might be helpful in the prediction of restenosis after coronary angioplasty. In contrast, tissue-type plasminogen activator (tPA) plasma levels appear unrelated to restenosis, and data regarding a possible role of urokinase-type plasminogen activator (uPA) in circulation are not available at present. Furthermore, a new hypothesis on the pathophysiological role of local PAI-1 overexpression as a beneficial negative feedback mechanism to limit excess cellular proliferation in atherogenesis and restenosis is presented.

Atherogenecity of lipoprotein(a) and oxidized low density lipoprotein: insight from in vivo studies of arterial wall influx, degradation and efflux

The accumulation of atherogenic lipoproteins in the arterial intima is pathognomonic of atherosclerosis. Modification of LDL by covalent linkage of apo(a) (resulting in the formation of Lp(a)) or oxidation probably enhances its atherogenecity. Although the metabolism of LDL in arterial intima has been rather extensively characterized, little has been known about the interaction of Lp(a) and oxidized LDL (ox-LDL) with the arterial wall. The present paper reviews a series of recent in vivo studies of the interaction of Lp(a) and ox-LDL with the arterial wall. The results have identified several factors that affect the accumulation of Lp(a) and ox-LDL in the arterial intima and have provided fresh insight into unique metabolic characteristics of Lp(a) and ox-LDL that may explain the large atherogenic potential of these modified LDL species.

Biochemical risk factors and patient's outcome: the case of lipoprotein(a)

Lipoprotein(a) (Lp(a)) is a genetic variant of low density lipoproteins and consists of the covalent association of the unique and enigmatic apolipoprotein(a) to apoliprotein B100. Despite the high degree of homology with low density lipoproteins, Lp(a) displays distinctive physico-chemical properties, function and metabolism. The present article reviews the main biological and clinical evidences about the association between raised concentration of Lp(a) and atherothrombotic diseases and provides tentative guidelines to improve the clinical usefulness of Lp(a) measurements.

Apolipoprotein(a) size polymorphism in young adults with ischemic stroke

High serum lipoprotein(a) (Lp(a)) concentration which is largely determined by genetic factors, mainly the apolipoprotein(a) (apo(a)) polymorphism, is associated with ischemic cerebrovascular disease. The aim of this study was to investigate whether apo(a) size was associated with acute ischemic stroke in young adults for which causal factors often remain undetermined. Lipid parameters, Lp(a) concentration and apo(a) isoform size distribution were determined in 90 young patients (37.4+/-8.7 years) with acute cerebral ischemia, and compared to those of control subjects with similar age and sex ratio. Apo(a) size was expressed as its apparent number of kringle 4 (Kr 4) repeats. Serum Lp(a) concentrations were significantly higher in patients than in controls (median values: 0.18 vs. 0.07 g/l, P=0.009) and were as expected inversely related to the number of kringle 4 repeats in both controls (r2=-0.61, P < 0.001) and patients (r2=-0.56, P < 0.001). However there was no difference in the apo(a) isoform size distributions between the two groups (median isoform size: 27 vs. 27 Kr 4, P=0.25). Lp(a) levels were increased as well in patients with size apo(a) isoform < or = 22 Kr 4 as in those with isoforms > 25 Kr 4. Multivariate analysis showed that apo(a) phenotype did not appear as a risk factor for cerebrovascular infarction. Thus, our results indicate that serum Lp(a) was significantly increased in young people with ischemic stroke but fail to reveal a role of small-sized apo(a) isoforms in the occurrence of this event. They suggest that other factors, genetic or environmental in nature, than the apo(a) size contribute to increase the serum Lp(a) concentrations in these young patients.

Usefulness of lipids, lipoprotein(a) and fibrinogen measurements in identifying subjects at risk of occlusive complications following vascular and endovascular surgery

The study was designed to establish the usefulness of measuring lipoprotein(a) [Lp(a)], total cholesterol, triglycerides, low-density lipoprotein [LDL]-cholesterol, high-density lipoprotein [HDL]-cholesterol, total-to-HDL-cholesterol ratio and fibrinogen in identifying subjects at risk of occlusive complications following vascular and endovascular surgery, including primary successful ileofemoral percutaneous transluminal angioplasty, infrainguinal and aortic bypass graft and carotid endarterectomy. A total of 68 volunteers subjected to vascular and endovascular surgery were recruited to the study. Six months after successful interventions, no occlusive complications verified by angiography were observed in 45 patients (66%; No-restenosis group), whereas significant restenosis or reocclusion occurred in 23 patients (34%; Restenosis group). Significant lower concentrations of Lp(a) (p=0.032), total cholesterol (p<0.0001), LDL-cholesterol (p=0.001) and total-to-HDL-cholesterol ratio (p<0.0001) and higher concentrations of HDL-cholesterol (p=0.048) were observed in the No-restenosis group compared to the Restenosis group. The concentrations of triglycerides (p=0.080) and fibrinogen (p=0.510) did not differ significantly between groups. In multivariate discriminant analysis, the best predictors of restenosis or reocclusion were in decreasing order: LDL-cholesterol, Lp(a), total-to-HDL-cholesterol ratio, HDL-cholesterol and total cholesterol. A statistical difference of particular interest was observed in the overall distribution of Lp(a) concentrations between groups (p<0.0001), occlusive complications being unlikely to occur in patients with Lp(a) concentrations below 50 mg L(-1). The potential interference from a concurrent acute phase response, the most common source of elevation of Lp(a) in humans, was less likely in view of the absence of differences in erythrocyte sedimentation rate between the No-restenosis and Restenosis groups (p=0.463). In conclusion, the results of the present investigation point to a definite role of the combined measurements LDL-cholesterol, Lp(a), total-to-HDL-cholesterol ratio, HDL-cholesterol and total cholesterol in the identification of subjects at risk of occlusive events following vascular and endovascular surgical procedures.

Lipoprotein(a) level does not predict restenosis after percutaneous transluminal coronary angioplasty

The serum lipoprotein(a) [Lp(a)] level is a known risk factor for arteriosclerotic coronary artery disease. However, its association with restenosis after percutaneous transluminal coronary angioplasty (PTCA) is controversial. We hypothesized that the Lp(a) level is a significant risk factor for restenosis after angioplasty through a pathophysiological mechanism leading to excess thrombin generation or inhibition of fibrinolysis. We designed a prospective study of the relation of Lp(a) to outcome after PTCA, in which we measured selected laboratory variables at entry and collected clinical, procedural, lesion-related, and outcome data pertaining to restenosis. Restenosis was defined as >50% stenosis of the target lesion by angiography or as ischemia in the target vessel distribution by radionuclide-perfusion scan. Before the patients underwent PTCA, blood was obtained by venipuncture for measurement of Lp(a), total cholesterol, thrombin-antithrombin (TAT) complex, alpha2-antiplasmin-plasmin (APP) complex, and plasminogen activator inhibitor-1 (PAI-1). Evaluable outcome data were obtained on 162 subjects, who form the basis of this report. Restenosis occurred in 61 subjects (38%). The Lp(a) level was not correlated significantly with TAT, APP, PAI-1, or the TAT-APP ratio. Levels of TAT, APP, and PAI-1 were not statistically different in the patients with versus those without restenosis. The median ratio of TAT to APP was 2-fold higher in the restenosis group, and this difference approached statistical significance (P=0.07). Univariate analysis was performed for the association of clinical, lesion-related, and procedural risk factors with restenosis. Lp(a) levels did not differ significantly in the restenosis versus no-restenosis group, whether assessed categorically (>25 mg/dL versus <25 mg/dL) or as a continuous variable by Mann-Whitney U test. The number of lesions dilated and the lack of family history of premature heart disease were significantly associated with restenosis (P=0.002 and P=0.008, respectively). A history of diabetes mellitus was of borderline significance (P=0.055). By multiple logistic regression analysis, the number of lesions dilated was the only variable significantly associated with restenosis (P=0.03). We conclude that the number of lesions dilated during PTCA is a significant risk factor for restenosis, whereas the serum Lp(a) level was not a significant risk factor for restenosis in our patient population. The TAT to APP ratio merits further study as a possible risk factor for restenosis.