The long-term outcome of percutaneous coronary intervention (PCI) compared to coronary artery bypass grafting (CABG) for unprotected left main coronary artery disease (ULMCAD) remains to be investigated. We identified 1,005 patients with ULMCAD of 15,939 patients with first coronary revascularization enrolled in the CREDO-Kyoto PCI/CABG Registry Cohort-2. Cumulative 3-year incidence of a composite of death/myocardial infarction (MI)/stroke was significantly higher in the PCI group than in the CABG group (22.7% vs 14.8%, p = 0.0006, log-rank test). However, the adjusted outcome was not different between the PCI and CABG groups (hazard ratio [HR] 1.30, 95% confidence interval [CI] 0.79 to 2.15, p = 0.30). Stratified analysis using the SYNTAX score demonstrated that risk for a composite of death/MI/stroke was not different between the 2 treatment groups in patients with low (<23) and intermediate (23 to 33) SYNTAX scores (adjusted HR 1.70, 95% CI 0.77 to 3.76, p = 0.19; adjusted HR 0.86, 95% CI 0.37 to 1.99, p = 0.72, respectively), whereas in patients with a high SYNTAX score (≥33), it was significantly higher after PCI than after CABG (adjusted HR 2.61, 95% CI 1.32 to 5.16, p = 0.006). In conclusion, risk of PCI for serious adverse events seemed to be comparable to that after CABG in patients with ULMCAD with a low or intermediate SYNTAX score, whereas PCI compared with CABG was associated with a higher risk for serious adverse events in patients with a high SYNTAX score.
In recent years, several observational studies have reported favorable clinical outcomes of percutaneous coronary intervention (PCI) using drug-eluting stents (DESs) in patients with unprotected left main coronary artery disease (ULMCAD). The Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) randomized trial reported comparable safety and efficacy outcomes of PCI compared to coronary artery bypass grafting (CABG) in the ULMCAD subset. Reflecting these study results, updated clinical guidelines for ULMCAD regarded PCI as an alternative to CABG in patients with less complex coronary anatomy or in patients with high surgical risk. However, the number of patients enrolled in these trials was insufficient in drawing definitive conclusions on the role of PCI in treating patients with ULMCAD. Therefore, we evaluated the long-term clinical outcome of PCI compared to CABG and the utility of the SYNTAX score for risk stratification in patients with ULMCAD in a large observational database in Japan.
Methods
The Coronary Revascularization Demonstrating Outcome Study in Kyoto (CREDO-Kyoto) PCI/CABG Registry Cohort-2 is a physician-initiated, noncompany-sponsored, multicenter registry that enrolled consecutive patients undergoing first coronary revascularization in 26 centers in Japan from January 2005 through December 2007. The relevant ethics committees in all 26 participating centers ( Supplementary Appendix A ) approved the research protocol. Because of retrospective enrollment, written informed consent from the patients was waived. However, patients who refused participation in the study when contacted for follow-up were excluded.
The study design and patient enrollment in the registry have been described in detail previously. Of 15,939 patients enrolled in the registry, the study population for the present prespecified subanalysis of the CREDO-Kyoto PCI/CABG Registry Cohort-2 consisted of 1,005 patients with ULMCAD (365 patients with PCI and 640 patients with CABG) excluding those patients who refused study participation, had concomitant noncoronary surgery, and had acute myocardial infarction (MI; Figure 1 ).
Demographic, angiographic, and procedural data were collected from hospital charts according to prespecified definitions by experienced research coordinators in an independent research organization (Research Institute for Production Development, Kyoto, Japan; Supplementary Appendix B ). Patients with ULMCAD were identified using angiographic information recorded in their hospital charts. Therefore, the present study population included those patients in whom PCI was not attempted for the LMCA lesions based on clinical judgments. Definitions for clinical characteristics are described in the Supplemental Text .
The SYNTAX score was calculated using the SYNTAX score calculator (available at: http://www.syntaxscore.com ) by a dedicated SYNTAX score committee ( Supplementary Appendix C ) in a blinded fashion to the clinical data. Intra- and interobserver variabilities of the SYNTAX score calculation in our group were previously reported. Cut-off values for SYNTAX score tertiles (low <23, intermediate 23 to 33, and high ≥33) were defined according to analysis in the SYNTAX trial.
The primary outcome measurement for the present analysis was defined as a composite of all-cause death, MI, and stroke. Other prespecified end points included all-cause death, cardiac death, MI, stroke, and coronary revascularization. Death was regarded as cardiac in origin unless obvious noncardiac causes could be identified. Any death during the index hospitalization for coronary revascularization was regarded as cardiac death. MI was defined according to the definition in the Arterial Revascularization Therapy Study. Stroke was defined as ischemic or hemorrhagic stroke requiring hospitalization with symptoms lasting >24 hours. Coronary revascularization was defined as PCI or CABG for any reason. Scheduled staged coronary revascularization procedures performed within 3 months of the initial procedure were not regarded as follow-up events but were included in the index procedure.
Collection of follow-up information was conducted mainly through review of inpatient and outpatient hospital charts by clinical research coordinators in the independent research organization. Additional follow-up information was collected through contact with patients, relatives, and/or referring physicians by sending mail with questions on vital status, additional hospitalizations, and status of antiplatelet therapy. Death, MI, stent thrombosis, and stroke were adjudicated by the clinical event committee ( Supplementary Appendix D ).
Because final data collection for follow-up events was initiated on July 1, 2009, follow-up events were censored on this date. Median follow-up duration for surviving patients was 1,027 days (interquartile range 734 to 1,311). Complete 1-year follow-up information was obtained in 95.4% of patients (96.4% in PCI group and 94.8% in CABG group, p = 0.24).
Categorical variables were presented as number and percentage and were compared with chi-square test. Continuous variables were expressed as mean ± SD or median with interquartile range. Continuous variables were compared using Student’s t test or Wilcoxon rank-sum test based on their distributions.
Cumulative incidence was estimated by the Kaplan–Meier method and differences were assessed using log-rank test. Effects of PCI compared to CABG for individual end points were expressed as hazard ratios (HRs) with 95% confidence intervals (CIs). In the entire study population, HR was estimated using nonparsimonious multivariable Cox proportional hazard models adjusted for the 30 clinically relevant factors listed in Table 1 , which was consistent with previous reports from the current registry. Continuous variables were dichotomized using clinically meaningful reference values or median values. Proportional hazard assumptions for potential independent risk-adjusting variables were assessed on log (time) versus log(−log) (survival) plots stratified by the variable, and assumptions were verified as acceptable for all variables. We incorporated the 26 participating centers in the Cox proportional hazard models as the stratification variable.
| PCI (n = 365) | CABG (n = 640) | p Value | |
|---|---|---|---|
| Clinical characteristics | |||
| Age (years) | 71.4 ± 10.1 | 69.4 ± 9.2 | 0.001 |
| Age ≥75 years ⁎ † | 151 (41%) | 208 (33%) | 0.005 |
| Men ⁎ | 259 (71%) | 490 (77%) | 0.051 |
| Body mass index (kg/m 2 ) | 23.4 ± 3.4 | 23.2 ± 3.0 | 0.35 |
| Body mass index <25.0 kg/m 2 ⁎ | 271 (74%) | 467 (73%) | 0.66 |
| Unstable angina pectoris | 52 (14%) | 71 (11%) | 0.15 |
| Hypertension ⁎ | 313 (86%) | 542 (85%) | 0.65 |
| Diabetes mellitus ⁎ | 155 (42%) | 291 (45%) | 0.36 |
| On insulin therapy | 35 (9.6%) | 93 (15%) | 0.02 |
| Current smoker ⁎ | 79 (22%) | 157 (25%) | 0.30 |
| Heart failure ⁎ | 76 (21%) | 131 (20%) | 0.89 |
| Ejection fraction (%) | 59.3 ± 14.7 | 60.2 ± 13.4 | 0.34 |
| Ejection fraction ≤40% | 34 (12%) | 56 (9.5%) | 0.30 |
| Mitral regurgitation grade 3/4 ⁎ | 25 (6.9%) | 17 (2.7%) | 0.002 |
| Previous myocardial infarction ⁎ | 70 (19%) | 105 (16%) | 0.27 |
| Previous stroke (symptomatic) ⁎ | 54 (15%) | 75 (12%) | 0.16 |
| Peripheral vascular disease ⁎ | 45 (12%) | 76 (12%) | 0.83 |
| Estimated glomerular filtration rate (ml/min/1.73 m 2 ) | 62.2 (45.7–74.5) | 61.0 (46.6–72.1) | 0.20 |
| Estimated glomerular filtration rate <30 ml/min/1.73 m 2 without hemodialysis ⁎ † | 19 (5.2%) | 38 (5.9%) | 0.63 |
| Hemodialysis ⁎ † | 26 (7.1%) | 44 (6.9%) | 0.88 |
| Anemia (hemoglobin <11.0 g/dl) ⁎ | 72 (20%) | 128 (20%) | 0.92 |
| Platelet count <100 × 10 9 /L ⁎ | 3 (0.8%) | 19 (3.0%) | 0.02 |
| Chronic obstructive pulmonary disease ⁎ | 12 (3.3%) | 17 (2.7%) | 0.57 |
| Liver cirrhosis ⁎ | 9 (2.5%) | 19 (3.0%) | 0.64 |
| Malignancy ⁎ | 58 (16%) | 69 (11%) | 0.02 |
| Procedural characteristics | |||
| Number of target lesions or anastomoses | 2.00 ± 1.03 | 3.09 ± 1.04 | <0.0001 |
| Extent of coronary artery disease | <0.0001 | ||
| Isolated unprotected left main coronary artery disease | 31 (8.5%) | 57 (8.9%) | |
| Unprotected left main coronary artery + 1-vessel disease | 89 (24.4%) | 108 (16.9%) | |
| Unprotected left main coronary artery + 2-vessel disease | 132 (36.2%) | 182 (28.4%) | |
| Unprotected left main coronary artery + 3-vessel disease | 113 (31.0%) | 293 (45.8%) | |
| Target of proximal left anterior descending coronary artery ⁎ | 174 (48%) | 451 (70%) | <0.0001 |
| Target of chronic total occlusion ⁎ | 45 (12%) | 166 (26%) | <0.0001 |
| Emergency procedure | 34 (9.3%) | 50 (7.8%) | 0.41 |
| SYNTAX score | 26.5 (21–34) | 30 (22–40) | <0.0001 |
| Low <23 | 123 (34.4%) | 154 (26.8%) | |
| Intermediate 23–33 | 131 (36.6%) | 177 (30.8%) | 0.0002 |
| High ≥33 | 104 (29.1%) | 243 (42.3%) | |
| Total number of stents | 2.78 ± 1.70 | — | — |
| Total stent length (mm) | 58.7 ± 41.0 | — | — |
| Stent use | 357 (98%) | — | — |
| Drug-eluting stent use | 277 (78%) | — | — |
| Internal thoracic artery use | — | 629 (98%) | — |
| Off pump | — | 414 (65%) | — |
| Baseline medications | |||
| Antiplatelet therapy | |||
| Thienopyridine | 362 (99%) | 72 (11%) | <0.0001 |
| Ticlopidine | 316 (87%) | 67 (94%) | 0.07 |
| Clopidogrel | 46 (13%) | 4 (5.6%) | |
| Aspirin | 361 (99%) | 632 (99%) | 0.83 |
| Cilostazol ⁎ | 45 (12%) | 41 (6.4%) | 0.002 |
| Other medications | |||
| Statins ⁎ | 184 (50%) | 199 (31%) | <0.0001 |
| β Blockers ⁎ | 110 (30%) | 174 (27%) | 0.32 |
| Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker ⁎ | 191 (52%) | 211 (33%) | <0.0001 |
| Nitrates ⁎ | 170 (47%) | 230 (36%) | 0.001 |
| Calcium channel blockers ⁎ | 171 (47%) | 332 (52%) | 0.13 |
| Nicorandil ⁎ | 94 (26%) | 277 (43%) | <0.0001 |
| Warfarin ⁎ | 30 (8.2%) | 244 (38%) | <0.0001 |
| Proton pump inhibitors ⁎ † | 92 (25%) | 263 (41%) | <0.0001 |
| H 2 blockers ⁎ | 78 (21%) | 204 (32%) | 0.0003 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
