Abstract
Objectives
To evaluate the success rates and outcome of the hybrid algorithm for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) by a single operator in two different clinical settings.
Methods
We compared 279 consecutive CTO PCIs performed by a single, high-volume operator using the hybrid algorithm in two different clinical settings. Data were collected through the PROGRESS CTO Registry. We compared 145 interventions performed in a community program (cohort A) with 134 interventions performed in a referral center (cohort B).
Results
Patient in cohort B had more complex lesions with higher J-CTO (3.0 vs. 3.41; p < 0.001) and Progress CTO (1.5 vs.1.8, P = 0.003) scores, more moderate to severe tortuosity (38% vs. 64%; p < 0.001), longer total occlusion length (25 vs. 40 mm; p < 0.001) and higher prevalence of prior failed CTO PCI attempts (15% vs. 35%; p = 0.001). Both technical (95% vs. 91%; p = 0.266) and procedural (94% vs. 88%; p = 0.088) success rates were similar between the two cohorts despite significantly different lesion complexity. Overall major adverse cardiovascular events were higher in cohort B (1.4% vs. 7.8%; p = 0.012) without any significant difference in mortality (0.7% vs. 2.3%, p = 0.351).
Conclusions
In spite of higher lesion complexity in the setting of a quaternary-care referral center, use of the hybrid algorithm for CTO PCI enabled similarly high technical and procedural success rates as compared with those previously achieved by the same operator in a community-based program at the expense of a higher rate of MACE.
1
Introduction
The hybrid algorithm for chronic total occlusion percutaneous coronary intervention (CTO PCI) emphasizes critical review of prior angiograms and the use of a two-guide catheter intervention to allow for seamless transition between multiple antegrade and retrograde approaches . The decision on the best subsequent approach is determined by an analysis of 4 major angiographic parameters; 1) the location of the proximal cap, 2) the lesion length, 3) the quality of the distal vessel, and 4) the suitability of collaterals for retrograde techniques. Thus the hybrid approach serves to demystify the treatment of CTOs by creating a uniform method for CTO PCI planning, allowing for a standardized and reproducible approach for crossing CTOs.
The hybrid algorithm has been adopted by several operators and has resulted in a significant improvement in success rates without a difference in major complications . We therefore sought to investigate if use of the hybrid algorithm was reproducible across two distinct practice settings. One operator (KA) moved from a community-based program to an urban quaternary referral center. We hypothesized that despite treating more angiographic complex lesions in a patient population with greater clinical morbidity use of the hybrid algorithm for CTO PCI would allow for similar success rates without differences in major complications.
2
Methods
Using the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention ([PROGRESS CTO Registry, Clinicaltrials.gov ID: NCT02061436 ] ) we analyzed 279 consecutive CTO PCIs performed by a single, high-volume operator using the hybrid algorithm. Clinical and angiographic characteristics were compared between 145 interventions performed in a 147 bed community hospital (cohort A) and 134 interventions performed in an 877 bed quaternary-care referral center (cohort B).
Chronic total occlusions were defined as coronary obstructions with thrombolysis in myocardial infarction (TIMI) flow grade 0 for at least three months duration. Estimation of the occlusion duration was based on the first onset of anginal symptoms, prior history of myocardial infarction in the target vessel territory, or comparison with a prior angiogram. Technical success was defined as angiographic evidence of <30% residual stenosis with restoration of TIMI 3 antegrade flow in the CTO target vessel. Procedural success was defined as technical success with no procedural major adverse cardiovascular events (MACE), including death, Q-wave myocardial infarction (troponin or creatine kinase leak was not classified as a major complication as it often occurs transiently post CTO-PCI and resolves spontaneously), recurrent cardiac symptoms requiring repeat target vessel PCI or coronary artery bypass surgery (CABG), cardiac tamponade requiring pericardiocentesis or surgery, and stroke before hospital discharge. Major bleeding was defined as bleeding causing hemoglobin drop >3 g/dl or bleeding requiring transfusion or surgical intervention. Vascular access complications included major bleeding from the access site or other complication requiring surgical intervention.
Continuous data were summarized as mean ± standard deviation for normally distributed data or median and interquartile range (IQR) for non-normally distributed data, and compared using t-test. Categorical data were presented as frequencies or percentages and compared using chi square or Fisher’s exact test, as appropriate. A two-sided p-value of <0.05 was considered statistically significant.
2
Methods
Using the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention ([PROGRESS CTO Registry, Clinicaltrials.gov ID: NCT02061436 ] ) we analyzed 279 consecutive CTO PCIs performed by a single, high-volume operator using the hybrid algorithm. Clinical and angiographic characteristics were compared between 145 interventions performed in a 147 bed community hospital (cohort A) and 134 interventions performed in an 877 bed quaternary-care referral center (cohort B).
Chronic total occlusions were defined as coronary obstructions with thrombolysis in myocardial infarction (TIMI) flow grade 0 for at least three months duration. Estimation of the occlusion duration was based on the first onset of anginal symptoms, prior history of myocardial infarction in the target vessel territory, or comparison with a prior angiogram. Technical success was defined as angiographic evidence of <30% residual stenosis with restoration of TIMI 3 antegrade flow in the CTO target vessel. Procedural success was defined as technical success with no procedural major adverse cardiovascular events (MACE), including death, Q-wave myocardial infarction (troponin or creatine kinase leak was not classified as a major complication as it often occurs transiently post CTO-PCI and resolves spontaneously), recurrent cardiac symptoms requiring repeat target vessel PCI or coronary artery bypass surgery (CABG), cardiac tamponade requiring pericardiocentesis or surgery, and stroke before hospital discharge. Major bleeding was defined as bleeding causing hemoglobin drop >3 g/dl or bleeding requiring transfusion or surgical intervention. Vascular access complications included major bleeding from the access site or other complication requiring surgical intervention.
Continuous data were summarized as mean ± standard deviation for normally distributed data or median and interquartile range (IQR) for non-normally distributed data, and compared using t-test. Categorical data were presented as frequencies or percentages and compared using chi square or Fisher’s exact test, as appropriate. A two-sided p-value of <0.05 was considered statistically significant.
3
Results
Between December 2011 and December 2015 a total of 279 consecutive CTO-PCIs were performed at two institutions by the same operator. Mean age was 65.7 ± 10.1 years and 79.8% were men. Patients in cohort B had more prior myocardial infarctions (29.9% vs. 49.2%, p = 0.002), and higher creatinine levels (1.0 vs. 1.07, p = 0.045). Left ventricular ejection fraction (LVEF) in cohort B was numerically lower, though the difference did not reach statistical significance (50.6 ± 12.4 vs. 47.2 ± 14.5, p = 0.063). Similarly, there was a trend toward increased diabetes mellitus in cohort B (46.4 vs. 58.1%, p = 0.055). Baseline characteristics were otherwise similar in both groups and are summarized in Table 1 .
| Variable | Overall (N = 270) | Community program (N = 141) | Referral center (N = 129) | p-value |
|---|---|---|---|---|
| Age (years) | 65.7 ± 10.1 | 66.5 ± 8.9 | 65.4 ± 10.5 | 0.521 |
| Male, sex, % | 79.8 | 81.2 | 78.3 | 0.56 |
| Diabetes mellitus, % | 52.0 | 46.4 | 58.1 | 0.055 |
| Hypertension, % | 87.3 | 87.1 | 87.6 | 0.893 |
| Dyslipidemia, % | 93.3 | 92.9 | 93.8 | 0.758 |
| Smoking (current or quit within 1 year), % | 21.1 | 26.1 | 15.5 | ⁎ 0.035 |
| LVEF % | 49.1 ± 13.5 | 50.6 ± 12.4 | 47.2 ± 14.5 | 0.063 |
| Heart failure % | 27.6 | 25.0 | 30.2 | 0.348 |
| Prior myocardial infarction, % | 39.5 | 29.9 | 49.2 | ⁎ 0.002 |
| Family history of premature CAD | 32.6 | 27.2 | 40.1 | 0.066 |
| Prior CABG, % | 41.5 | 36.9 | 46.5 | 0.109 |
| Prior PCI, % | 81.9 | 94.3 | 68.2 | ⁎ <0.001 |
| CVD, % | 9.7 | 8.5 | 10.9 | 0.501 |
| PAD, % | 10.4 | 8.5 | 12.4 | 0.295 |
| Baseline creatinine | 1.03 (0.87, 1.30) | 1.0 (0.84, 1.23) | 1.07 (0.91, 1.40) | 0.045 |
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