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A total of 2,056 patients who underwent PCI between 2014 and 2016 were included. Of these, 261 were lost to follow-up, and 1,795 were analyzed (Figure 1). The low- and high-LDL-C groups included 1,202 (LDL-C < 2.6 mmol/L) and 593 patients (LDL-C ≥ 2.6 mmol/L), respectively. The median follow-up was 20.2 months (range = 9–39.6 months).
Table 1 and Supplementary Tables S1–S3 (available in www.besjournal.com) provide the baseline clinical characteristics and angiographic findings. The patients had a mean age of 64.9 ± 10.6 years, 72.4% were men, and 22.3% had diabetes mellitus. Overall, participants in the high-LDL-C group had higher risk factors. Compared with the low-LDL-C group, the high-LDL-C group had a higher prevalence of previous ACS and left circumflex culprit vessel but a lower prevalence of elderly, hypertension, chronic kidney disease, and primary PCI. Ezetimibes were more frequently used in the high-LDL-C group.
Variables
n (%)Overall population Propensity-matched population Low-LDL-C
(n = 1,202)High-LDL-C
(n = 593)P value Low-LDL-C
(n = 443)High-LDL-C
(n = 443)P value Age (yrs) 66.3 ± 10.5 63.0 ± 10.2 < 0.001* 62.3 ± 10.5 63.7 ± 10.5 0.996 Male 909/1,200 (75.8) 390/590 (66.1) < 0.001* 297/443 (67.0) 307/443 (69.3) 0.471 Body-mass index 24.6 ± 3.4 24.9 ± 3.5 0.208 25.6 ± 3.2 24.6 ± 3.0 0.326 Diabetes 272/1,176 (23.1) 129/585 (22.1) 0.661 98/443 (22.1) 98/443 (22.1) 1.000 Hypertension 781/1,175 (66.5) 346/585 (59.1) 0.003* 257/443 (58.0) 266/443 (60.0) 0.539 Congestive heart failure 29/1,116 (2.6) 22/555 (4.0) 0.126 10/408 (2.5) 14/409 (3.4) 0.411 ACS 488/1,175 (41.5) 272/580 (46.9) 0.033* 175/443 (39.5) 181/443 (40.9) 0.681 Previous cerebrovascular disease 107/1,176 (9.1) 44/585 (7.5) 0.266 37/443 (8.4) 30/443 (6.8) 0.374 Current smoker 337/1,174 (28.7) 186/583 (31.9) 0.167 119/443 (26.9) 134/442 (30.3) 0.255 Current alcohol consumption 241/1,173 (20.5) 133/582 (22.9) 0.267 87/442 (19.7) 105/442 (23.8) 0.142 Note. Values are mean ± SD, n (%), or n/N (%). ACS, acute coronary syndrome. *P < 0.05. Table 1. Baseline characteristics-demographic characteristic
Following 1:1 propensity score matching, 886 patients were matched (Table 1). In the propensity-matched population, no significant differences existed in baseline characteristics between the two groups except for triglyceride.
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Upon admission, the median LDL-C levels were 1.85 in the Low-LDL-C group and 3.15 mmol/L in High-LDL-C group (P < 0.001, Table 2). Among patients whose blood samples were obtained at a median of 20.2 months of follow-up, the median LDL-C levels were 1.46 mmol/L in the low-LDL-C group and 1.89 mmol/L in the high-LDL-C group (P < 0.001, Table 2). During follow-up, reductions in the LDL-C levels were 0.39 mmol/L (21.1%) in the low-LDL-C group and 1.26 mmol/L (40.0%) in the high-LDL-C group. A total of 66.8% of the overall population achieved the target LDL-C level, with 75.9% in the low-LDL-C group and 46.5% in the high-LDL-C group. Following 1:1 propensity score matching, 73.8% of patients in the low-LDL-C and 49.5% in the high-LDL-C group achieved the target LDL-C level.
Variables Overall population Propensity-matched population Low-LDL-C (n = 1,202) High-LDL-C (n = 593) P value Low-LDL-C (n = 443) High-LDL-C (n = 443) P value LDL cholesterol, mmol/L At admission† 1.85 (1.49–2.21) 3.15 (2.73–3.57) < 0.001* 1.84 (1.57–2.12) 3.20 (2.76–3.64) < 0.001* Follow-up† 1.46 (1.14–1.79) 1.89 (1.32–2.46) < 0.001* 1.45 (1.07–1.82) 1.78 (1.15–2.41) < 0.001* Difference 0.39 1.26 0.39 1.42 Reduction (%) 21.1 40 21.2 44.3 P-value < 0.001* < 0.001* < 0.001* < 0.001* Patients reach the treatment LDL-C goal (< 1.8 mmol/L), no./total no (%) 912/1,202 (75.9) 275/591 (46.5) < 0.001* 327/443 (73.8) 219/442 (49.5) < 0.001* Note. †Median (Interquartile range). *P < 0.050. Table 2. LDL-C levels (mmol/L) at admission and follow-up
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Table 3 shows the clinical outcomes. During follow-up, MACE occurred in 202 patients (11.3%), whereas 20 patients (1.1%) had all-cause mortality, 11 (0.6%) had cardiac death, 2 (0.1%) had MI, 171 (9.5%) had revascularization, 13 (2.2%) had an ischemic stroke, and 2 had a hemorrhagic stroke. Supplementary Figure S1 (available in www.besjournal.com), Figure 2, and Table 2 demonstrate the cumulative incidences of clinical outcomes in the two groups.
Variables Low-LDL-C
(n = 1,202)High-LDL-C
(n = 593)Unadjusted Adjusted 1§ HR (95% CI) P HR (95% CI) P A. Overall population (N = 1,795) Primary end point MACE 126 (13.0) 76 (16.1) 1.202 (0.904−1.598) 0.205 1.009 (0.701−1.452) 0.960 Secondary end points Cardiac death, MI, or revascularization 111 (11.8) 71 (15.2) 1.281 (0.951−1.725) 0.103 1.051 (0.718−1.538) 0.800 Cardiac death or MI 4 (0.4) 9 (1.8) 4.509 (1.388−14.644) 0.012* 10.300 (1.046−101.461) 0.046* All−cause death 8 (0.7) 12 (2.4) 3.019 (1.234−7.387) 0.015* 4.030 (1.088−14.934) 0.037* Cardiac death 3 (0.3) 8 (1.6) 5.347 (1.418−20.156) 0.013* 137.729 (0.845−2.253 × 104) 0.058 MI 1 (0.1) 1 (0.2) 1.984 (0.124−31.727) 0.628 0.279 (0.000−8.350 × 1045) 0.981 Revascularization 108 (11.6) 63 (13.5) 1.158 (0.800−1.580) 0.355 0.975 (0.659−1.443) 0.900 Any nonfatal stroke 12 (1.2) 3 (0.5) 0.498 (0.141−1.765) 0.280 0.712 (0.169−3.001) 0.643 Ischemic stroke 10 (1.0) 3 (0.5) 0.597 (0.164−2.169) 0.433 0.756 (0.172−3.311) 0.710 Hemorrhagic stroke 2 (0.2) 0 (0.0) 0.026 (0.000−5.988 × 103) 0.563 0.000 (0.000−5.533 × 10237) 0.978 Variables Low-LDL-C
(n = 443)High-LDL-C
(n = 443)Unadjusted Adjusted 2§ HR (95% CI) P HR (95% CI) P B. Propensity-matched population (N = 886) Primary end point MACE 51 (13.9) 52 (15.1) 1.032 (0.702−1.519) 0.872 0.981 (0.656−1.468) 0.926 Secondary end points Cardiac death, MI, or revascularization 46 (12.7) 48 (14.1) 1.061 (0.708−1.590) 0.775 1.015 (0.665−1.548) 0.946 Cardiac death or MI 0 (0) 4 (1.3) 65.957 (0.021−2.050 × 105) 0.045* 3.836 × 107 (0−1.734 × 10132) 0.905 All−cause death 1 (0.2) 7 (2.1) 7.156 (0.880−58.180) 0.031* 6.887 (0.748−63.371) 0.088 Cardiac death 0 (0) 4 (1.3) 65.957 (0.021−2.050 × 105) 0.045* 3.836 × 107 (0−1.734 × 10132) 0.905 MI 0 (0) 0 (0) 0 0 0 0 Revascularization 46 (12.7) 44 (12.8) 0.967 (0.640−1.462) 0.873 0.926 (0.602−1.425) 0.727 Any nonfatal stroke 5 (1.6) 3 (0.7) 0.597 (0.143−2.499) 0.480 0.520 (0.117−2.300) 0.389 Ischemic stroke 5 (1.6) 3 (0.7) 0.597 (0.143−2.499) 0.480 0.520 (0.117−2.300) 0.389 Hemorrhagic stroke 0 (0) 0 (0) 0 0 0 0 Note. Cox regression analyses were performed before and after PSM. §Covariates were adjusted including age, gender, hypertension, current smoker, ACS, eGFR, left anterior descending, left circumflex, right coronary artery, stent length, primary PCI, coronary calcification, clopidogrel, warfarin, statin, fibrates, ezetimibe and LDL−C level. *P < 0.05. Table 3. Clinical outcomes in the study, according to the different baseline LDL-C level
Figure 2. Cumulative incidence of clinical outcomes in the propensity-matched population. Kaplan–Meier curves for the (A) primary endpoint, (B) all-cause death, (C) revascularization, and (D) any nonfatal stroke in the propensity-matched population. Cumulative event rates for the primary composite endpoint of death from all-cause death, recurrent nonfatal MI, unexpected coronary revascularization (occurring at least 30 days after PCI), and nonfatal stroke during the overall study period.
Kaplan–Meier event rates for the risk of all-cause mortality were significantly lower in the low-LDL-C group than in the high-LDL-C group [adjusted hazard ratio (HR): 4.030, 95% confidence interval (CI): 1.088–14.934; P = 0.037, Table 3, Supplementary Figures S1 and Figure 3]. However, no significant differences were observed in the rates of MACE or other secondary endpoints between the two groups (Table 3, Supplementary Figure S1, and Figure 3).
Figure 3. Clinical outcomes of the study, according to the baseline LDL-C level. (A) Adjusted 1: The models included age, gender, hypertension, current smoker, ACS, eGFR, left anterior descending, left circumflex, right coronary artery, stent length, primary PCI, coronary calcification, clopidogrel, warfarin, statin, fibrates, ezetimibe, and LDL-C level during follow-up as covariates. (B) Adjusted 2: The models included triglyceride, ACS, multivessel coronary disease, left anterior descending, right coronary artery, stent length, statin, fibrates, ezetimibe, and LDL-C level during follow-up as covariates.
Variables Overall population Propensity-matched population Low-LDL-C (N = 1,202) High-LDL-C (N = 593) P value Low-LDL-C (N = 443) High-LDL-C (N = 443) P value LDL-C, mmol/L† 1.85 (1.49–2.21) 3.15 (2.73–3.57) < 0.001* 1.84 (1.57–2.12) 3.20 (2.76–3.64) < 0.001* HDL-C, mmol/L† 0.95 (0.77–1.14) 1.02 (0.85–1.20) < 0.001* 0.98 (0.84–1.12) 1.04 (0.90–1.18) 0.216 TG, mmol/L† 1.28 (0.85–1.72) 1.55 (1.12–1.98) < 0.001* 1.44 (0.79–2.09) 1.53 (1.10–1.97) < 0.001* eGFR (SD), mL/min/1.73 m2‡† 71.86 (56.03–87.69) 77.11 (58.83–95.39) < 0.001* 75.62 (60.48–90.76) 79.83 (60.44–99.21) 0.362 Note. LDL-C, low density lipoprotein cholesterol; HDL-C, high density lipoprotein cholesterol; TG, triglyceride; eGFR, estimated glomerular filtration rate. †Median (Interquartile range). ‡eGFR is estimated by using the Modification of Diet in Renal Disease equation. *P < 0.050. Table S1. Baseline characteristics-laboratory findings
Variables
N (%)Overall population Propensity-matched population Low-LDL-C (N = 1,202) High-LDL-C (N = 593) P value Low-LDL-C (N = 443) High-LDL-C (N = 443) P value Multivessel coronary disease 186/1,147 (16.2) 108/558 (19.4) 0.107 91/443 (20.5) 91/443 (20.5) 1.000 Culprit vessel Left main 104/1,147 (9.1) 49/558 (8.8) 0.846 42/443 (9.5) 39/443 (8.8) 0.727 Left anterior descending 718/1,147 (62.6) 344/558 (61.6) 0.704 271/443 (61.2) 278/443 (62.8) 0.628 Left circumflex 220/1,147 (19.2) 134/558 (24.0) 0.021* 114/443 (25.7) 107/443 (24.2) 0.587 Right 278/1,147 (24.2) 136/558 (24.4) 0.951 106/443 (23.9) 104/443 (23.5) 0.874 Lesion type B2 or C 1,067/1,108 (96.3) 502/529 (94.9) 0.183 404/430 (94.0) 398/420 (94.8) 0.610 Calcification lesion 191/1,111 (17.2) 95/534 (17.8) 0.764 81/431 (18.8) 75/425 (17.6) 0.664 CTO 52/1,111 (4.7) 37/536 (6.9) 0.062 17/431 (3.9) 27/424 (6.4) 0.109 Primary PCI 251/1,147 (21.9) 93/558 (16.7) 0.012* 80/443 (18.1) 72/443 (16.3) 0.476 Stent length (mm) 39 ± 22 40 ± 23 0.209 53 ± 28 55 ± 25 0.110 Stent diameter ≥ 2.5 mm 934/1,147 (81.4) 457/558 (81.9) 0.814 352/443 (79.5) 362/443 (81.7) 0.396 Stent number 2.3 ± 1.0 2.2 ± 0.8 0.498 2.2 ± 0.9 2.2 ± 0.9 0.762 Note. CTO, chronic total occlusion. *P < 0.050. Table S2. Baseline characteristics-coronary angiographic and procedural findings
Variables
N (%)Overall population Propensity-matched population Low-LDL-C (N = 1,202) High-LDL-C (N = 593) P value Low-LDL-C (N = 443) High-LDL-C (N = 443) P value Medications Antiplatelet drug Aspirin 1,163/1,202 (96.8) 581/591 (98.3) 0.058 432/443 (97.5) 436/443 (98.4) 0.341 Clopidogrel 1,079/1,202 (89.8) 535/591 (90.5) 0.615 408/443 (92.1) 403/443 (91.0) 0.546 Ticagrelor 6/1,202 (0.5) 4/591 (0.7) 0.738 0/443 (0.0) 3/443 (0.7) 0.083 Cilostazol 32/1,202 (2.7) 8/591 (1.4) 0.078 10/443 (2.3) 6/443 (1.4) 0.313 Warfarin 15/1,202 (1.2) 8/591 (1.4) 0.852 9/443 (2.0) 5/443 (1.1) 0.281 Lipid-lowering drug Statin 1,186/1,202 (98.7) 582/591 (98.5) 0.745 439/443 (99.1) 437/443 (98.6) 0.525 Fibrates 8/1,202 (0.7) 2/591 (0.3) 0.382 4/443 (0.9) 2/443 (0.5) 0.413 Ezetimibe 93/1,202 (7.7) 147/591 (24.9) < 0.001* 71/443 (16.0) 79/443 (17.8) 0.474 ACEI or ARB 715/1,202 (59.5) 352/591 (59.6) 0.975 249/443 (56.2) 256/443 (57.8) 0.635 Beta-blocker 671/1,202 (55.8) 303/591 (51.3) 0.069 230/443 (51.9) 219/443 (49.4) 0.460 CCB 302/1,202 (25.1) 151/591 (25.5) 0.846 96/443 (21.7) 117/443 (26.4) 0.099 Note. ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin-receptor blocker; CCB, Dihydropyridine calcium-channel blocker. *P < 0.050. Table S3. Baseline characteristics-medications
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Following adjustment for potential confounders, including triglyceride, ACS, multivessel coronary disease, left anterior descending, right coronary artery, stent length, statin, fibrates, ezetimibe, and LDL-C during follow-up in the propensity-matched population, the low-LDL-C group had a trend of decreased all-cause mortality risk (adjusted HR: 6.887, 95% CI: 0.748–63.371, P = 0.088; Table 3 and Figures 2 and 3). However, no significant differences were detected in the risks of MACE or other secondary endpoints between the groups.
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Baseline Demographics and Angiographic Findings
LDL-C Data
Clinical Outcomes in the Overall Population
Clinical Outcomes in the Propensity-matched Population
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