The aim of the present study was to evaluate the effect of concurrent chronic total occlusion (CTO) in a noninfarct-related artery (IRA) on the long-term prognosis in patients with ST-segment elevation myocardial infarction and multivessel coronary disease. Of 1,658 consecutive patients with ST-segment elevation myocardial infarction, 666 with multivessel coronary disease who underwent percutaneous coronary intervention from 1999 to 2004 were included in the present analysis. The patients were divided into 2 groups: no CTO and CTO. The first group included 462 patients without CTO (69%) and the second group included 204 patients with CTO in a non-IRA (31%). The in-hospital mortality rate was 6.3% and 21.1% (p < 0.0001) and the 5-year mortality rate was 22.5% and 40.2% (p < 0.0001) for the no-CTO and CTO patients, respectively. Multivariate analysis revealed that after correction for baseline differences CTO in a non-IRA was a strong, independent predictor of 5-year mortality in patients undergoing percutaneous coronary intervention (hazard ratio 1.85; 95% confidence interval 1.35 to 2.53; p = 0.0001). In conclusion, the presence of CTO in a non-IRA in patients with ST-segment elevation myocardial infarction and multivessel coronary disease is a strong and independent risk factor for greater 5-year mortality.
The objective of the present investigation, given that the available data are limited, was to evaluate the effect of chronic total occlusion (CTO) in a noninfarct-related artery (IRA) on the clinical outcomes. We studied the in-hospital and long-term follow-up outcomes of patients with ST-segment elevation myocardial infarction (STEMI) and multivessel coronary disease (MVD) who underwent percutaneous coronary intervention (PCI) limited to the IRA. Using the findings from a large interventional cardiology center, we hoped to identify the differences in patient characteristics and clinical course of patients with and without CTO. Also, an analysis of the factors that affect the long-term prognosis was conducted, and an additional multifactorial analysis was undertaken in patients with MVD and CTO.
Methods
From January 1999 to December 2004, 1,658 consecutive patients with STEMI underwent PCI at our center. In this cohort of patients, we conducted a single-center analysis of 666 patients with MVD. Of the 666 patients with MVD, we found MVD without CTO in non-IRA segments in 462 (69%; no-CTO group) and MVD with CTO in 204 (31%; CTO group). MVD was defined as >70% diameter stenosis of ≥1 major epicardial coronary artery or its major branch, remote from the IRA, as determined by visual assessment. CTO was defined as a non-IRA with 100% luminal narrowing before PCI without anterograde flow or with anterograde or retrograde filling through collateral vessels. The differentiation between CTO and acute occlusion was determined by the compilation among the morphology of the occlusion (presence of fresh thrombus, bridge, or ipsi- or contralateral collaterals), electrocardiographic recording, and a possible history of previously documented acute coronary events in the same territory. The patients with STEMI after coronary artery bypass grafting were excluded from the present analysis. The patients with cardiogenic shock on admission—defined clinically as symptoms of shock or peripheral hypoperfusion and hemodynamically as systemic systolic pressure <90 mm Hg or systemic systolic pressure 90 to 110 mm Hg during intra-aortic balloon pumping or while using inotropic drugs—were included in the present analysis.
The clinical data from all patients with STEMI were prospectively recorded in a computerized database as a part of a single-center acute coronary syndromes registry. Follow-up information was obtained by direct telephone interviews and outpatient visits and from the National Health Fund database.
At our center, an interventional cardiologist is on duty 24 hr/day. All patients with acute STEMI were treated with 300 to 500 mg aspirin, 300 mg clopidogrel (since 2001), with 75 mg/day thereafter or ticlopidine 250 mg twice daily for ≥8 weeks, 5,000 to 10.000 U unfractionated heparin, and 2.5 to 5 mg of morphine intravenously. Acute STEMI was defined as stenocardial pain lasting ≥30 minutes, with electrocardiographic features of an evolving myocardial infarction (i.e., ST-segment elevation ≥0.1 mV in ≥2 limb leads or ≥0.2 mV in ≥2 precardial leads or new-onset left bundle branch block, with the interval since onset not >12 hours or, in the case of cardiogenic shock, 18 to 24 hours). Depending on the patient’s condition, other medications were also used. The patients were then referred for urgent coronary angiography. Standard guidewires, balloon catheters, and coronary stents were used in these procedures. In some patients with myocardial infarction complicated by cardiogenic shock, depending on their clinical status, intra-aortic balloon pumping was performed. Vascular sheaths were removed at normalization of the blood coagulation parameters (i.e., activated partial thromboplastin time). After intervention, in addition to thienopiridynes, all patients received 150 mg/day of aspirin indefinitely. They also received β blockers, angiotensin-converting enzyme inhibitors, and statins, if these agents were not otherwise contraindicated.
The 12-month and 5-year mortality were assessed. The angiographic success of IRA angioplasty was defined as Thrombolysis In Myocardial Infarction grade 3 flow and <30% residual stenosis.
Continuous parameters with a normal distribution are presented as the mean ± SD. The significance of differences between the mean values was tested using Student’s t test. Qualitative parameters were analyzed using a chi-square test (when the numbers were anticipated to be <5, Yates’ correction for continuity was implemented). Mortality curves ≤5 years after STEMI were constructed using the Kaplan-Meier method and were compared using the log–rank test. To assess the effect of particular parameters on mortality, multivariate analysis was performed using stepdown Cox proportional hazards regression modeling and expressed as the hazard ratio, with the 95% confidence interval. All clinical and angiographic variables were used in the risk-adjusted models. The level of statistical significance was p < 0.05 (2-tailed). The calculations and statistical analyses were performed using Statistica, version 7.0 (StatSoft, Tulsa, Oklahoma).
Results
The characteristics of the 1658 patients with STEMI, with and without MVD, who underwent PCI in the analyzed period are listed in Table 1 . The baseline clinical and angiographic characteristics of the study groups are listed in Table 2 . Patients with CTO had a greater prevalence of diabetes, previous myocardial infarction, and cardiogenic shock on admission than did the patients without CTO. The in-hospital parameters differed significantly between the 2 groups.
| Variable | No. of Narrowed Coronary Arteries | p Value | |
|---|---|---|---|
| 1 (n = 992; 60%) | >1 (n = 666; 40%) | ||
| Age (years) | 56 ± 10 | 61 ± 11 | <0.0001 |
| Men | 738 (74%) | 479 (72%) | NS |
| Duration of pain (hours) | 4.8 ± 4 | 5.6 ± 5 | 0.001 |
| Thrombolysis before percutaneous coronary intervention | 234 (24%) | 120 (18%) | 0.006 |
| Anterior wall myocardial infarction | 422 (43%) | 256 (38%) | NS |
| Arterial hypertension ⁎ | 478 (48%) | 396 (60%) | <0.0001 |
| Diabetes mellitus | 158 (16%) | 163 (25%) | <0.001 |
| Hyperlipidemia † | 579 (59%) | 399 (60%) | NS |
| Current smoker | 664 (62%) | 368 (56%) | 0.001 |
| Previous myocardial infarction | 120 (12%) | 202 (30%) | <0.0001 |
| Cardiogenic shock on admission | 59 (6%) | 97 (15%) | <0.0001 |
| Infarct-related artery | NS | ||
| Left anterior descending artery | 438 (44%) | 250 (38%) | |
| Right coronary artery | 394 (40%) | 292 (44%) | |
| Left circumflex artery | 153 (15%) | 111 (17%) | |
| Baseline Thrombolysis In Myocardial Infarction flow grade 0–1 | 692 (70%) | 585 (88%) | <0.0001 |
| Stent implantation | 751 (76%) | 461 (69%) | 0.003 |
| Glycoprotein IIb/IIIa blocker | 43 (4%) | 32 (5%) | NS |
| Final Thrombolysis In Myocardial Infarction flow grade 0–2 | 96 (10%) | 109 (16%) | <0.001 |
| Angiographic success | 892 (90%) | 556 (84%) | <0.001 |
| 5-Year mortality | 134 (13%) | 186 (28%) | <0.0001 |
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