Derivation and validation of the J-CTO extension score for pre-procedural prediction of major adverse cardiac and cerebrovascular events in patients with chronic total occlusions

Abstract

We developed a prediction model of long-term risk after percutaneous coronary intervention (PCI) for coronary chronic total occlusion (CTO) based on pre-procedural clinical information. A total of 4,139 eligible patients, who underwent CTO-PCI at 52 Japanese centers were included. Specifically, 1,909 patients with 1-year data were randomly divided into the derivation (n = 1,273) and validation (n = 636) groups. Major adverse cardiac and cardiovascular event (MACCE) was the primary endpoint, including death, stroke, revascularization, and non-fatal myocardial infarction. We assessed the performance of our model using the area under the receiver operating characteristic curve (AUC) and assigned a simplified point-scoring system. One-hundred-thirty-eight (10.8%) patients experienced MACCE in the derivation cohort with hemodialysis (HD: odds ratio [OR] = 2.55), left ventricular ejection fractions (LVEF) <35% (OR = 2.23), in-stent occlusions (ISO: OR = 2.27), and diabetes mellitus (DM: OR = 1.72). The AUC of the derivation model was 0.650. The model's performance was similar in the validation cohort (AUC, 0.610). When assigned a point for each associated factor (HD = 3, LVEF <35%, ISO = 2, and DM = 1 point), the average predicted versus the observed MACCE probability using the Japan-CTO extension score for the low, moderate, high, and very high risk groups was 8.1% vs. 7.3%, 16.9% vs. 15.9%, 22.0% vs. 26.1%, and 56.2% vs. 44.4%, respectively. This novel risk model may allow for the estimation of long-term risk and be useful in disseminating appropriate revascularization procedures.

Fig 1. Study flow.

When the patients had CTO lesions in several vessels, only the vessel that was treated first was analyzed.

Fig 2. TREND checklist.

We checked 22 points including TREND statement checklist. All points were included in our study.

Fig 3. Incidence of MACCE: Comparison between the derivation and validation groups.

We created a scoring model, named J-CTO extension score, according to the odds ratio of multivariate analysis of MACCE at the 1-year follow-up, as follows: hemodialysis = 3, LVEF <35% = 2, in-stent occlusion = 2, and DM = 1. This model was successful in predicting MACCE incidence at the 1-year follow-up with stepwise alterations in the derivation and validation sets. LVEF, left ventricular ejection fraction; MACCE, major advanced cardiovascular events; J-CTO, Japan-chronic total occlusion.

Fig 4. Internal validation of the J-CTO extension score.

A: This figure revealed calibration of the J-CTO extension score in the validation group. The average predicted versus observed probability of MACCE with the J-CTO extension score for each quartile (categorized as low, moderate, high, and very high-risk groups) was: 8.1% vs. 7.3%, 16.9% vs. 15.9%, 22.0% vs. 26.1%, and 56.2% vs. 44.4% of the observed and predicted scores, respectively. B: The agreements between the observed and predicted risks of MACCE at the 1-year follow-up, with developed risk-scoring methods were assessed across the 10 groups divided according to the risk score in the validation cohort. There was a significant correlation between the values of the observed and predicted risk in the 10 groups (r = 0.77). MACCE, major advanced cardiovascular events; J-CTO, Japan-chronic total occlusion.

Fig 5. Comparison between the J-CTO extension score and other scoring models of CTO-PCI.

A: ROC curve of the overall population. The AUC of the J-CTO, CL, and PROGRESS scores was 0.518 (95% CI, 0.473–0.563, p = 0.406), 0.540 (95% CI, 0.496–0.583, p = 0.066), and 0.514 (95% CI, 0.472–0.556, p = 0.509), respectively. Conversely, the J-CTO extension score was only associated with the incidence of MACCE at the 1-year follow-up; the AUC was 0.634 (95% CI, 0.590–0.678, p <0.0001). B: ROC curve of the derivation group. The AUC of the J-CTO, CL, and PROGRESS scores was 0.514 (95% CI, 0.459–0.569, p = 0.600), 0.543 (95% CI, 0.489–0.597, p = 0.105), and 0.515 (95% CI, 0.463–0.567, p = 0.585), respectively. Conversely, the J-CTO extension score was only associated with the incidence of MACCE at the 1-year follow-up; the AUC was 0.650 (95% CI, 0.598–0.703, p <0.0001). 4C: ROC curve of the validation group. The AUC the J-CTO, CL, and PROGRESS scores was 0.528 (95% CI, 0.452–0.604, p = 0.44), 0.535 (95% CI, 0.463–0.608 p = 0.33), and 0.512 (95% CI, 0.442–0.581, p = 0.751), respectively. Conversely, the J-CTO extension score was only associated with the incidence of MACCE at the 1-year follow-up; the AUC was 0.610 (95% CI, 0.532–0.688, p <0.003). CI, confidence interval; AUC, area under the curve, ROC, receiver operating characteristic; J-CTO, Japan-chronic total occlusion score; MACCE, major advanced cardiovascular events.