From January 2005 to December 2015, a total of 739 patients received revascularization treatment for CTO at Taipei Veterans General Hospital. The mean age of was 68 ± 13 years, and most of the patients were male (675, 91%). Most patients had multi-vessel disease (607, 82%), and right coronary artery was the most common treated CTO vessel (362, 49%). 76 (10%) patients underwent bypass surgery prior to CTO PCI. The mean J-CTO score was 2.5 ± 0.97. Chronic kidney disease was present in 165 patients (22%). Most CTO lesions were crossed by antegrade wire escalation technique/parallel wire technique, while the retrograde approach was tried in only 56 patients (7.6%). Successful revascularization was achieved in 619 (84%) patients of entire cohort. Compared to patients with successful revascularization, the failed PCI group had poorer renal function, higher prevalence of multivessel CTO, and longer CTO length. Drug eluting stent was used in 317 (43%) patients. The baseline clinical and angiographic characteristics are shown in Table 1.
Table 1
Baseline demographics and angiographic characteristics of entire population with successful and Failed revascularization
| Entire population (n = 739) |
| Success (n = 619) | Failed (n = 120) | P value |
Age (yrs) | 67 ± 13 | 69 ± 13 | 0.14 |
Gender (male) | 568 (92) | 107 (89) | 0.38 |
Hypertension | 467 (75) | 96 (80) | 0.35 |
DM | 265 (43) | 48 (40) | 0.61 |
Hyperlipidemia | 267 (43) | 53 (44) | 0.84 |
Prior stroke | 51 (8) | 11 (9) | 0.72 |
PAD | 34 (6) | 11 (9) | 0.14 |
Smoking | 253 (41) | 47 (39) | 0.76 |
Prior CABG | 61 (10) | 15 (13) | 0.41 |
LVEF (%) | 49 ± 12 | 48 ± 13 | 0.61 |
eGFR, MDRDc (ml/min) | 84 ± 33 | 76 ± 34 | 0.01 |
LDL (mg/dl) | 102 ± 35 | 97 ± 32 | 0.19 |
HbA1C (%) | 8.0 ± 3.8 | 7.6 ± 1.7 | 0.51 |
Location of CTO | | | |
LAD | 271 (44) | 46 (38) | 0.31 |
LCx | 159 (26) | 37 (31) | 0.26 |
RCA | 293 (47) | 63 (53) | 0.32 |
J CTO score | 2.45 ± 1.00 | 2.55 ± 0.96 | 0.32 |
MVD | 501 (81) | 106 (88) | 0.07 |
Lesion length (mm) | 38 ± 18 | 32 ± 11 | 0.01 |
Lesion width (mm) | 3.2 ± 3.6 | 3.0 ± 0.5 | 0.73 |
Primary retrograde | 48 (8) | 8 (7) | 0.34 |
Values are given as mean and standard deviation or numbers and percentages. |
DM, diabetes mellitus; PCI, percuatneous coronary intervention; PAD, peripheral arterial disease; CABG, coronary artery bypass graft surgery; LVEF, left ventricular ejection fraction; eGFR, estimated glomerular filtration rate; MDRDc, modification of diet in renal disease Chinese; LDL, low density lipoprotein; CTO, chronic total occlusion; CAD, coronary artery disease; LAD, left anterior descending; LCx: left cirumflex; RCA, right coronary artery; MVD, multivessel significant coronar y artery disease |
Totally 313 (42%) patients are diabetics and 426 (58%) patients are non-diabetics. Among diabetic patients, 68 (21.7%) patients received insulin treatment. Compared to non-diabetic patients, diabetic patients were significantly older, with higher percentage of hypertension, worse renal function, multi-vessels disease, and reduced LVEF. There was no statistically difference in J-CTO score between two groups of diabetics and non-diabetics. However, the revascularization successful rate was similar between diabetic patients (265, 84%,) and non-diabetics patients (354, 83%, p = 0.614). The angiographic procedure and characteristics were not significantly different between the two groups. (Tables 1 & 2)
Table 2
Baseline demographics and angiographic characteristics of diabetes and non diabetes population with successful and Failed revascularization
| Diabetes mellitus (n = 313) | Non Diabetes (n = 426) |
| Success (n = 265) | Failed (n = 48) | P value | Success (n = 354) | Failed (n = 72) | P value |
Age (yrs) | 70 ± 12 | 70 ± 13 | 0.71 | 66 ± 14 | 68 ± 13 | 0.10 |
Gender (Male) | 229 (86) | 42 (88) | 1 | 339 (96) | 65 (90) | 0.08 |
Hypertension | 226 (85) | 42 (88) | 0.83 | 241 (68) | 54 (75) | 0.27 |
Hyperlipidemia | 121 (46) | 26 (54) | 0.35 | 146 (41) | 27 (38) | 0.60 |
Prior stroke | 25 (9) | 8 (17) | 0.13 | 26 (7) | 3 (4) | 0.45 |
PAD | 18 (7) | 7 (15) | 0.08 | 16 (5) | 4 (6) | 0.76 |
Smoking | 92 (35) | 17 (35) | 1.00 | 161 (46) | 30 (42) | 0.60 |
Prior CABG | 28 (11) | 8 (17) | 0.22 | 33 (9) | 7 (10) | 0.83 |
LVEF (%) | 47 ± 12 | 47 ± 12 | 0.92 | 50 ± 12 | 48 ± 14 | 0.36 |
eGFR, MDRDc (ml/min) | 78 ± 36 | 67 ± 32 | 0.06 | 89 ± 29 | 82 ± 34 | 0.06 |
LDL (mg/dl) | 98 ± 33 | 92 ± 30 | 0.39 | 106 ± 36 | 100 ± 34 | 0.29 |
HbA1C | 7.9 ± 1.7 | 7.7 ± 1.7 | 0.57 | - | - | - |
OAD | 191 (72) | 32 (67) | 0.62 | - | - | - |
Insulin (%) | 55 (21) | 13 (27) | 0.62 | - | - | - |
Location of CTO | | | | | | |
LAD | 107 (40) | 16 (33) | 0.42 | 164 (46) | 30 (42) | 0.52 |
LCx | 68 (26) | 16 (33), | 0.29 | 91 (26) | 21 (29) | 0.56 |
RCA | 138 (52) | 30 (63) | 0.21 | 155 (44) | 33 (46) | 0.80 |
J CTO score | 2.54 ± 1.00 | 2.66 ± 1.00 | 0.38 | 2.31 ± 0.99 | 2.40 ± 0.89 | 0.537 |
MVD | 224 (85) | 46 (96) | 0.04 | 277 (78) | 60 (83) | 0.43 |
Lesion length (mm) | 38 ± 18 | 31 ± 9 | 0.12 | 38 + 18 | 32 + 12 | 0.05 |
Lesion width (mm) | 3.0 ± 1.6 | 3.0 ± 0.6 | 0.96 | 3.3 + 4.5 | 3.0 + 0.3 | 0.72 |
Primary retrograde | 22 (9) | 2 (5) | 0.85 | 26 (8) | 6 (8) | 1.00 |
Values are given as mean and standard deviation or numbers and percentages. |
PCI, percuatneous coronary intervention; PAD, peripheral arterial disease; CABG, coronary artery bypass graft surgery; LVEF, left ventricular ejection fraction; eGFR, estimated glomerular filtration rate; MDRDc, modification of diet in renal disease Chinese; LDL, low density lipoprotein; HbA1C, glycated hemoglobin; OAD, oral anti-diabetic drug; CTO, chronic total occlusion; CAD, coronary artery disease; LAD, left anterior descending; LCx, left circumflex; RCA, right coronary artery; MVD, multivessel significant coronary artery disease. |
The incidences of clinical outcomes (all-cause mortality, CV mortality, nonfatal MI, stroke and MACCE) followed up for 3 years (median: 5 years, interquartile range: 1–10 years) were summarized in Table 3. (Fig. 1). In entire population, there were no significant differences in the incidence of all- cause mortality, CV mortality, nonfatal MI and MACCE (Hazard ratio (HR): 0.593, 95% confidence interval (CI): 0.349–1.008, P: 0.054; HR: 0.472, 95% CI: 0.217–1.024, P: 0.057; HR: 0.867, 95% CI: 0.294–2.563, P: 0.797; HR: 0.734, 95% CI: 0.449–1.200, P: 0.218 respectively) between successful revascularization group and failed revascularization group. In contrast, the risk of long-term all-cause mortality, CV mortality and MACCE in successful recanalization group were significantly lower comparing to those of failed group in diabetics subgroup (HR: 0.307, 95% CI: 0.156–0.604, P: 0.001; HR: 0.266, 95% CI: 0.095–0.748, P: 0.013; HR: 0.454, 95% CI: 0.246–0.837, P: 0.011 respectively), whereas there were no significant differences in these endpoints in non-diabetes population (all-cause mortality: HR: 1.334, 95% CI: 0.521–3.417, P: 0.548; CV mortality: HR: 0.885, 95% CI: 0.252–3.107, P: 0.849; nonfatal MI: HR: 1.423, 95% CI: 0.175–11.565, P: 0.741; and MACCE: HR: 1.351, 95% CI: 0.573–3.188, P: 0.491) (Table 4). Figure 1 shows the cumulative survival curves free from 3-year all-cause mortality determined using the Kaplan-Meier method between successful and failed revascularization group in entire population and diabetic/non-diabetic patients, with the outcome significantly worse only in those diabetic patients undergoing failed revascularization procedure. (p = 0.001).
Table 3
Baseline demographics and angiographic characteristics of diabetes population with successful and Failed PCI after propensity score matching
| Success (n = 188) | Failed (n = 47) | P value |
Age, yrs | 71 ± 12 | 71 ± 13 | 0.96 |
Gender (Male) | 158 (84) | 41 (87) | 0.66 |
Hypertension | 160 (85) | 42 (89) | 0.64 |
Hyperlipidemia | 80 (43) | 24 (51) | 0.33 |
Prior stroke | 19 (10) | 6 (13) | 0.60 |
PAD | 16 (9) | 7 (15) | 0.27 |
Smoking | 61 (32) | 17 (36) | 0.73 |
Prior CABG | 18 (10) | 9 (19) | 0.08 |
LVEF, % | 47 ± 12 | 47 ± 12 | 0.92 |
eGFR, MDRDc (ml/min) | 69 ± 29 | 68 ± 30 | 0.76 |
LDL (mg/dl) | 98 ± 34 | 93 ± 29 | 0.51 |
HbA1C, % | 7.7 ± 1.6 | 8 ± 1.5 | 0.49 |
Location of CTO | | | |
LAD | 14 (26) | 5 (39) | 0.50 |
LCx | 28 (44) | 1 (11) | 0.08 |
RCA | 23 (37) | 10 (56) | 0.18 |
Multivessel CTO | 29 (15) | 15 (32) | 0.05 |
J CTO score | 2.4 ± 0.5 | 2.5 ± 0.6 | 0.60 |
MVD | 163 (87) | 45 (96) | 0.05 |
Lesion length (mm) | 37 ± 18 | 31 ± 8 | 0.12 |
Lesion width (mm) | 3.0 ± 2.0 | 3.0 ± 0.6 | 0.92 |
Retrograde approach | 14 (8) | 2 (5) | 0.89 |
Values are given as mean and standard deviation or numbers and percentages. |
PCI = percuatneous coronary intervention; PAD = peripheral arterial disease; CABG = coronary artery bypass graft surgery; LVEF = left ventricular ejection fraction; eGFR = estimated glomerular filtration rate; LDL = low density lipoprotein; CTO = chronic total occlusion; CAD = coronary artery disease, LAD, left anterior descending; LCx, left circumflex; RCA, right coronary artery; MVD, multivessel significant coronary artery disease. |
Table 4
Various clinical outcomes up to 3 years by Kaplan-Meier curved analysis
| Incidence of event at 3 years [n (%)] |
| Procedure | HR (95% CI) | P value |
Entire population | Successful PCI (n = 619) | Failed PCI (n = 120) | | |
All cause mortality | 59 (10) | 18 (15) | 0.593 (0.349–1.008) | 0.054 |
CV mortality | 22 (4) | 9 (8) | 0.472 (0.217–1.024) | 0.057 |
Nonfatal MI | 18 (3) | 4 (3) | 0.867 (0.294–2.563) | 0.797 |
MACE | 80 (13) | 20 (17) | 0.734 (0.449–1.200) | 0.218 |
Diabetes patients | Successful PCI (n = 265) | Failed PCI (n = 48) | | |
All cause mortality | 25 (9) | 13 (27) | 0.307 (0.156–0.604) | 0.001 |
CV mortality | 9 (3) | 6 (13) | 0.266 (0.095–0.748) | 0.012 |
Nonfatal MI | 11 (4) | 3 (6) | 0.652 (0.182–2.338) | 0.512 |
MACE | 39 (15) | 14 (29) | 0.454 (0.246–0.837) | 0.011 |
Non diabetes patients | Successful PCI (n = 354) | Failed PCI (n = 72) | | |
All cause mortality | 34 (10) | 4 (7) | 1.334 (0.521–3.417) | 0.548 |
CV mortality | 13 (4) | 3 (4) | 0.885 (0.252–3.107) | 0.849 |
Nonfatal MI | 7 (2) | 1 (1) | 1.423 (0.175–11.565) | 0.741 |
MACE | 41 (12) | 6 (8) | 1.351 (0.573–3.188) | 0.491 |
Diabetes patients after matching | Successful PCI (n = 188) | Failed PCI (n = 47) | | |
All cause mortality | 21 (11) | 12 (26) | 0.386 (0.188–0.789) | 0.009 |
CV mortality | 7 (4) | 6 (13) | 0.268 (0.090–0.798) | 0.018 |
Nonfatal MI | 8 (4) | 3 (6) | 0.584 (0.154–2.210) | 0.429 |
MACE | 28 (15) | 13 (28) | 1.511 (0.338–6.753) | 0.589 |
CV, cardiovascular; MI, myocardial infarct; MACCE, major adverse cardiovascular and cerebrovascular events (defined as the composite of all-cause mortality, cardiovascular mortality, non fatal myocardial infarct and stroke) |
In multivariate Cox-regression analysis, successful CTO revascularization remained an independent predictor of 3 years all-cause mortality in diabetic patients (HR: 0.289, 95% CI: 0.125–0.667, P value: 0.004) after adjusting age, renal function, prior stroke, prior peripheral arterial disease, left ventricular ejection fraction. (Table 5)
Table 5
Univariate and multivariate analysis of successful revascularization on three-years all cause mortality before matching
| Univariate analysis | Multivariate analysis |
| HR (95% CI) | P value | HR (95% CI) | P value |
Successful revascularization | 0.307 (0.156–0.604) | 0.001 | 0.289 (0.125–0.667) | 0.004 |
Age | 1.044 (1.015–1.075) | 0.003 | 1.034 (0.997–1.073) | 0.071 |
Gender | 3.607 (0.873–14.902) | 0.076 | - | - |
eGFR | 0.990 (0.981–1.000) | 0.053 | 0.996 (0.985–1.007) | 0.465 |
LDL | 0.991 (0.979–1.003) | 0.150 | - | - |
HbA1C | 0.830 (0.637–1.081) | 0.166 | - | - |
Prior stroke | 2.409 (1.158–5.012) | 0.019 | 1.961 (0.725–5.308) | 0.185 |
Prior PAD | 3.109 (1.494–6.469) | 0.002 | 3.322 (1.276–8.646) | 0.014 |
Hypertension | 1.302 (0.513–3.302) | 0.579 | - | - |
LAD | 1.575 (0.872–2.846) | 0.132 | - | - |
LVEF | 0.960 (0.933–0.988) | 0.005 | 0.955 (0.927–0.984) | 0.003 |
MDRDc: Modification of diet in renal disease Chinese; LDL, low density lipoprotein; HbA1C, glycated hemoglobulin; PAD, peripheral arterial disease; LAD, left anterior descending; LVEF, left ventricular ejection fraction. |
Table 6
Univariate and multivariate analysis of successful revascularization on three-years all cause mortality after matching
| Univariate analysis | Multivariate analysis |
| HR (95% CI) | P value | HR (95% CI) | P value |
Successful revascularization | 0.386 (0.188–0.789) | 0.009 | 0.348 (0.142–0.851) | 0.021 |
Age | 1.045 (1.010–1.081) | 0.012 | 1.041 (0.997–1.087) | 0.069 |
Gender | 2.789 (0.667–11.673) | 0.160 | - | - |
eGFR | 0.987 (0.975–0.999) | 0.040 | 0.995 (0.979–1.011) | 0.516 |
LDL | 0.993 (0.980–1.007) | 0.346 | - | - |
HbA1C | 0.671 (0.386–1.169) | 0.159 | - | - |
Prior stroke | 2.598 (1.123–6.009) | 0.026 | 2.207 (0.736–6.621) | 0.158 |
Prior PAD | 1.825 (0.703–4.740) | 0.217 | - | - |
Hypertension | 1.603 (0.488–5.261) | 0.437 | - | - |
LAD | 0.194 (0.024–1.577) | 0.125 | - | - |
LVEF | 0.965 (0.933–0.999) | 0.045 | 0.961 (0.928–0.996) | 0.027 |
MDRDc: Modification of diet in renal disease Chinese; LDL, low density lipoprotein; HbA1C, glycated hemoglobulin; PAD, peripheral arterial disease; LAD, left anterior descending; LVEF, left ventricular ejection fraction. |
Propensity score-adjusted clinical outcomes
To reduce the effect of treatment selection bias and compensate for potential confounding factors in this observational study, we calculated the propensity score by using multiple logistic regression analysis incorporating patient’s age, gender, renal function variables. After propensity score matching, there were no significant differences in the baseline characteristics between the successful PCI and failed PCI group of diabetes population (Table 3). In propensity score matched population, successful CTO revascularization was associated with reduced 3-years all-cause mortality and CV mortality only in diabetes population (all-cause mortality; HR 0.386, 95% CI: 0.188–0.789, P: 0.009, CV mortality; 0.280, 95% CI: 0.094–0.834, P: 0.018, Fig. 1). In contrast, the risks of non-fatal MI and MACCE were not reduced after successful CTO recanalization in diabetic patients (HR: 0.584, 95% CI: 0.154–2.210, P: 0.429; HR: 1.511, 95% CI: 0.338–6.753, P: 0.589, Table 4). In addition, there were no significant differences in clinical outcomes after successful or failed CTO recanalization in propensity score matched non-diabetic group.