Abstract
Objective
To assess hard major adverse clinical events (HMACE) after successful versus failed percutaneous coronary intervention for chronic total occlusion (PCI-CTO).
Background
There are limited data regarding long-term HMACE risks based on PCI-CTO success.
Methods
First-time PCI was performed in 438 consecutive patients with 473 target CTO lesions. Patients after procedural success (n = 355; 378 CTO lesions) and failure (n = 83; 95 CTO lesions) were followed for an average 40 months (7–77 months range). We compared HMACE (composite of cardiac death, non-fatal myocardial infarction (MI), and stroke) dependent on the success of PCI.
Results
The incidence of HMACE was low, with a total of 16 events, and did not differ {6% vs.3.1%, HR = 0.47; CI [0.16–1.35; p = 0.162} dependent on the success of PCI-CTO. There were less cardiac deaths {0.3% vs. 1.2%, RR = 0.22; CI [0.01–3.50];p = 0.283}, non fatal MI {1.1% vs.3.6%, RR = 0.27; CI [0.06–1.22], p = 0.089}, but more strokes {1.7% vs.1.2%, RR = 1.32; CI [0.16–10.99], p = 0.795} after successful PCI-CTO.
Conclusions
The risks of HMACE after PCI-CTO over long-term follow-up were minimal, and do not depend on the procedure success. This unexpected finding somewhat challenge the aggressive interventional approach, and should be confirmed in the adequately powered randomized trial.
Highlights
- •
The hard major adverse clinical events (HMACE) after successful versus failed percutaneous coronary intervention for chronic total occlusion (PCI-CTO) are uncertain.
- •
There are limited data regarding long-term HMACE risks dependent on PCI-CTO outcomes.
- •
We analyzed first-time PCI in 438 consecutive patients with 473 target CTO lesions. Patients after procedural success (n = 355; 378 CTO lesions) and failure (n = 83; 95 CTO lesions) were followed for an average 40 months (7-77 months range).
- •
We compared HMACE (composite of cardiac death, non-fatal myocardial infarction (MI), and stroke) dependent on the outcomes of PCI-CTO.
- •
The incidence of HMACE was low, with a total of 16 events, and did not differ {6% vs.3.1%, HR = 0.47; CI [0.16-1.35; p = 0.162} dependent on the success of PCI-CTO. There were less cardiac deaths {0.3% vs. 1.2%, RR = 0.22; CI [0.01-3.50];p = 0.283}, non fatal MI {1.1% vs.3.6%, RR = 0.27; CI [0.06-1.22], p = 0.089}, but more strokes {1.7% vs.1.2%, RR = 1.32; CI [0.16-10.99], p = 0.795} after successful PCI-CTO.
- •
The risks of HMACE after PCI-CTO over long-term follow-up were minimal, and do not depend on the procedure success.
- •
This surprise finding somewhat challenge the aggressive interventional approach, and should be confirmed in the adequately powered randomized trial.
- •
Obviously, yet unclear, compensatory mechanism to protect from failed CTO recanalization should be considered, and explored further.
1
Introduction
Native chronic total occlusions (CTO) are the most complex and challenging coronary lesions for interventional cardiologists, while the CTO patients treated with percutaneous coronary interventions (PCI) are targeted infrequently (10–15%) . likely due to historically low procedural success rates (up to 35% of failure), technical complexity, high equipment use, and risk of major periprocedural complications . As compared with the failure, successful PCI-CTO may offer significant clinical benefits, such as improvement in angina, left ventricular function, potential survival advantages with a reduction for the need of CAGB . However, the impact of recanalization success on hard major adverse clinical events (HMACE) is unclear in general, and in East Asians in particular. Therefore, the objective of the current observational study was to establish long-term HMACE in a prospective CTO registry in Busan, Korea (B-CTO).
2
Methods
2.1
Study population
A prospective, single-center B-CTO has been initiated in September 1999, and is currently open. The protocol for the registry was approved by the Institutional Ethics Committee of Dong-A University Hospital (Busan, Korea) and the overall study design and flow diagram are shown in Fig. 1 .
We enrolled 438 consecutive patients with 473 target CTO lesions after excluding 27 cases (incomplete or terminated PCI). The entire pool of CTO lesions was divided into procedural success (n = 355 patients with 378 CTOs) and failure groups (n = 83 patients with 95 CTOs). The definition of native CTO was 100% occluded coronary segment with Thrombolysis In Myocardial Infarction (TIMI) flow grade of 0, longer than 3 months duration according to the consensus in EuroCTO club . Duration was estimated based on the interval from the last episode of acute coronary syndrome (ACS), or in patients with no history of ACS from the first episode of exertional angina consistent with the location of the occlusion or previous coronary angiogram. Procedural success was defined as < 20% residual stenosis with TIMI flow grade ≥ 2 by visual estimation of the angiograms as previously described . We excluded patients presented with acute myocardial infarction within 4 weeks, cardiogenic shock; premature recanalization termination hemorrhagic diathesis; renal dysfunction (serum creatinine > 2.5 mg/dl); and life expectancy < 3 years.
2.2
PCI-CTO techniques
All patients were treated with aspirin, clopidogrel and initial bolus of intravenous unfractioned heparin (100 IU/kg) before PCI. The activated clotting time was maintained between 250 and 300 s, and monitored every 30 min. Glycoprotein IIb/IIIa inhibitors were permitted to use at the discretion of the interventional cardiologists.
The CTO guidewire strategies included the following: single-wire technique, parallel-wires technique and intravascular ultrasound-guided wiring technique, as well as retrograde wiring, including simple retrograde wiring, kissing wires, controlled antegrade retrograde tracking (CART) and reverse CART technique, as previously described . The Rendezvous techniques applied after a retrograde guidewire was successfully crossed a CTO into the proximal true lumen .
2.3
Clinical outcomes and definitions
The primary outcome was the composite HMACE rate (cardiac death, non-fatal myocardial infarction, and stroke) during clinical follow-up. The outcome data were collected through outpatient clinic, hospital records, and telephone interviews.
2.4
Statistical analysis
All analyses were performed on an intention-to-treat basis, unless stated otherwise. A descriptive analysis was performed by presenting data as mean (standard deviation, SD)/median (interquartile range, IQR) or number (proportion). Continuous variables were compared with a t-test or Wilcoxon rank sum test, and categorical variables were compared with chi-square statistics or Fisher’s exact test, as appropriate for the available data. The independent factors of PCI-CTO success were assessed in multivariate logistic regression analysis with a forward/backward elimination technique, and only candidate variables with a P value of less than 0.30 were selected for the final multivariate model. The association between the HMACE components and procedural success are expressed as adjusted odds ratio (OR) with 95% confidence intervals (CI). Hazard ratios (HR) and 95% CI estimated with Cox proportional-hazards model. The follow-up data were censored at the time of last contact or at 72 months. A two-tailed p-value of < 0.05 was the criteria for statistical significance. All statistical analyses were performed using PASW Statistics software (version 18.0; SPSS Inc., Chicago, IL, USA), and the R programming language (R Foundation for Statistical Computing).
2
Methods
2.1
Study population
A prospective, single-center B-CTO has been initiated in September 1999, and is currently open. The protocol for the registry was approved by the Institutional Ethics Committee of Dong-A University Hospital (Busan, Korea) and the overall study design and flow diagram are shown in Fig. 1 .
We enrolled 438 consecutive patients with 473 target CTO lesions after excluding 27 cases (incomplete or terminated PCI). The entire pool of CTO lesions was divided into procedural success (n = 355 patients with 378 CTOs) and failure groups (n = 83 patients with 95 CTOs). The definition of native CTO was 100% occluded coronary segment with Thrombolysis In Myocardial Infarction (TIMI) flow grade of 0, longer than 3 months duration according to the consensus in EuroCTO club . Duration was estimated based on the interval from the last episode of acute coronary syndrome (ACS), or in patients with no history of ACS from the first episode of exertional angina consistent with the location of the occlusion or previous coronary angiogram. Procedural success was defined as < 20% residual stenosis with TIMI flow grade ≥ 2 by visual estimation of the angiograms as previously described . We excluded patients presented with acute myocardial infarction within 4 weeks, cardiogenic shock; premature recanalization termination hemorrhagic diathesis; renal dysfunction (serum creatinine > 2.5 mg/dl); and life expectancy < 3 years.
2.2
PCI-CTO techniques
All patients were treated with aspirin, clopidogrel and initial bolus of intravenous unfractioned heparin (100 IU/kg) before PCI. The activated clotting time was maintained between 250 and 300 s, and monitored every 30 min. Glycoprotein IIb/IIIa inhibitors were permitted to use at the discretion of the interventional cardiologists.
The CTO guidewire strategies included the following: single-wire technique, parallel-wires technique and intravascular ultrasound-guided wiring technique, as well as retrograde wiring, including simple retrograde wiring, kissing wires, controlled antegrade retrograde tracking (CART) and reverse CART technique, as previously described . The Rendezvous techniques applied after a retrograde guidewire was successfully crossed a CTO into the proximal true lumen .
2.3
Clinical outcomes and definitions
The primary outcome was the composite HMACE rate (cardiac death, non-fatal myocardial infarction, and stroke) during clinical follow-up. The outcome data were collected through outpatient clinic, hospital records, and telephone interviews.
2.4
Statistical analysis
All analyses were performed on an intention-to-treat basis, unless stated otherwise. A descriptive analysis was performed by presenting data as mean (standard deviation, SD)/median (interquartile range, IQR) or number (proportion). Continuous variables were compared with a t-test or Wilcoxon rank sum test, and categorical variables were compared with chi-square statistics or Fisher’s exact test, as appropriate for the available data. The independent factors of PCI-CTO success were assessed in multivariate logistic regression analysis with a forward/backward elimination technique, and only candidate variables with a P value of less than 0.30 were selected for the final multivariate model. The association between the HMACE components and procedural success are expressed as adjusted odds ratio (OR) with 95% confidence intervals (CI). Hazard ratios (HR) and 95% CI estimated with Cox proportional-hazards model. The follow-up data were censored at the time of last contact or at 72 months. A two-tailed p-value of < 0.05 was the criteria for statistical significance. All statistical analyses were performed using PASW Statistics software (version 18.0; SPSS Inc., Chicago, IL, USA), and the R programming language (R Foundation for Statistical Computing).
3
Results
3.1
Baseline characteristics
The background demographics and clinical characteristics of the B-CTO Registry are outlined in Table 1 . Among all parameters only female gender has been associated with failed PCI-CTO. All other variables were not different dependent on revascularization success.
| Failure (n = 83) | Success (n = 355) | P value | |
|---|---|---|---|
| Age, years | 62 ± 10 | 61 ± 10 | 0.250 |
| ≥ 75, n (%) | 14 (16.9) | 36 (10.1) | 0.083 |
| ≥ 65, n (%) | 38 (45.8) | 143 (40.3) | 0.359 |
| Male gender, n (%) | 56 (67.5) | 278 (78.3) | 0.037 |
| BMI, kg/m 2 | 24.9 ± 3.4 | 25.0 ± 3.3 | 0.926 |
| BMI > 23 (Asia) | 59 (71.1) | 256 (72.1) | 0.851 |
| BMI ≥ 25 (WHO) | 36 (43.4) | 166 (46.8) | 0.577 |
| Cardiovascular risk factor, n (%) | |||
| Hypertension | 48 (57.8) | 194 (54.6) | 0.600 |
| Diabetes | 29 (34.9) | 130 (36.6) | 0.774 |
| Dyslipidemia | 16 (19.3) | 59 (16.6) | 0.563 |
| Current Smoking | 20 (24.1) | 91 (25.6) | 0.772 |
| Prior CVD, n (%) | |||
| Prior MI | 9 (10.8) | 55 (15.5) | 0.280 |
| Prior PCI | 20 (24.1) | 112 (31.5) | 0.188 |
| Prior CABG | 1 (1.1) | 6 (1.7) | > 0.999 |
| Clinical indication, n (%) | 0.431 | ||
| Stable angina | 30 (36.1) | 114 (32.1) | |
| Unstable angina | 30 (36.1) | 156 (43.9) | |
| Current MI | 23 (27.7) | 85 (23.9) | |
| CCS class † | 0.020 | ||
| I | 0 (0) | 3 (2.6) | |
| II | 2 (6.7) | 31 (27.2) | |
| III | 16 (53.3) | 59 (51.8) | |
| IV | 12 (40.0) | 21 (18.4) | |
| Syntax Score | 0.353 | ||
| Mean ± SD | 21.4 ± 8.5 | 22.6 ± 11.3 | |
| Median (95% CI) | 20.0 (19.5–23.2) | 20.5 (21.4–23.8) | |
| Syntax Score Class | 0.430 | ||
| Syntax Score ≤ 22 | 51 (61.4) | 200 (56.3) | |
| Syntax Score 23–32 | 20 (24.1) | 111 (31.3) | |
| Syntax Score ≥ 33 | 12 (14.5) | 44 (12.4) | |
| LVEF, % | 50.8 ± 12.0 | 50.4 ± 12.2 | 0.774 |
| LVEF < 50%, n (%) | 30 (36.1) | 134 (37.7) | 0.786 |
| LVEF < 40%, n (%) | 14 (16.9) | 68 (19.2) | 0.631 |
| LVEF < 35%, n (%) | 7 (8.4) | 38 (10.7) | 0.540 |
| Creatinine, mg/dl | 1.08 ± 0.81 | 1.05 ± 0.70 | 0.704 |
| Creatinine > 2.0, n (%) | 1 (1.2) | 8 (2.3) | 0.700 |
| ACEF score | 1.37 ± 0.55 | 1.34 ± 0.58 | 0.709 |
| Post-PCI | |||
| Post-PCI symptom | < 0.001 | ||
| Symptom-relief | 34 (41.0) | 242 (68.2) | |
| Symptom-residual | 49 (59.0) | 113 (31.8) | |
| Syntax Score | |||
| Mean ± SD | 21.4 ± 8.5 | 15.3 ± 11.1 | < 0.001 |
| Median (95% CI) | 20.0 (19.5–23.2) | 12.5 (14.2–16.5) | |
| Syntax Score Class | < 0.001 | ||
| Syntax Score ≤ 22 | 51 (61.4) | 292 (82.3) | |
| Syntax Score 23–32 | 20 (24.1) | 36 (10.1) | |
| Syntax Score ≥ 33 | 12 (14.5) | 27 (7.6) | |
| LVEF, % | 48.3 ± 15.7 | 49.5 ± 12.8 | 0.850 |
| LVEF < 50% | 15 (40.5) | 74 (49.0) | 0.355 |
| LVEF < 40% | 11 (29.7) | 46 (30.5) | 0.931 |
| LVEF < 35% | 10 (27.0) | 30 (19.9) | 0.340 |
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