The purpose of this study was to apply the UK-BCIS Chip score to identify those patients who, based on the variables that build up the score, meet the definition for complex PCI and to assess their risk of cardiovascular mortality at least 1 year follow-up in a Latin American population.

This is a retrospective cohort study of patients with chronic coronary syndrome, unstable angina and NSTEMI that underwent PCI in a Latin American hospital from January 2018 to March 2024. We enrolled a total of 346 patients. Patients were categorized into two groups according to whether (group 1) or not (group 2) they survived during follow-up; considering the variables that build up the score. A univariate survival analysis was performed for each variable under study, represented by a Kaplan-Meier curve. A cox regression model was performed to estimate cardiovascular mortality with statistically significant angiographic variables obtained at univariate analysis. The primary outcome was cardiovascular death at 1 year. 

Our population comprised 346 patients. Median age was 64±10.36 years, 70.5% were men. The most frequent comorbidity was hypertension, present in 70.5% of patients, followed by tobacco consumption in 54.3%. Patients of the group 2 had a higher prevalence of chronic kidney disease, in association with anemia and renal replacement therapy (7% vs 37.1%), (10.9% vs 30.3%) and (0.8% vs 12.4%) (P=.000). As well as peripheral arterial disease (16.3% vs 42.7%) (P= .000). And history of coronary artery bypass surgery (1.2 vs 7.9%) (P=.001). There was no other significant difference between groups.

Angiographic comparison showed that a higher 3-vessel PCI (9.7% vs 57.3%) (P=.000) characterized group 2. According to the AHA/ACC classification, group 2 had a higher prevalence of B2/C lesions (70.8% vs 86.5%) (P=.002); associated with moderate/severe calcification (28.0% vs 66.3%) (P=.000). The total length of the lesions was longer in group 2 (34.28 mm vs 57.90 mm) (P=.000); That correlates with an increase in the total length of implanted stents (34.76 mm vs 46.5 mm) (P=.000). A higher number of lesions treated was documented in group 2 ≥2 than in group 1 (P=.000). On the other hand, a higher prevalence of left main coronary artery PCI was done (1.2% vs 9%) (P=.000). A pre-procedure and post-procedure TIMI <3 were associated with higher mortality (P=.000). with a significant difference in the Syntax score I (13.42 vs 29.34) points between both groups.

Patients with score zero had a median follow-up length of 77 months (IQR: 76-78 months). Those with scores between 1 or 2 had a median follow-up length of 66 months (IQR: 62-69 months). Scores between 3 or 4 had a median follow-up length of 39 months (IQR: 34-43 months). Finally, those with a ≥5 score had a median follow-up length of 12 months (IQR: 7-16 months). C-index 0.86.

Cox regression model showed that total lesion length (HR1.080 [95% CI 1.065-0.1.95]; total length of the stents implanted (HR1.025 [95% CI 1.011-0.1.039], hospital readmissions (HR10.461 [95% CI 5.402-20.259]; and a higher punctuation of UK-BCIS Chip score (HR2.533 [95% CI 2.013-3.186]; were significantly associated with cardiovascular mortality. 

Among patients with chronic coronary syndrome, unstable angina and NSTEMI undergoing PCI an accurate stratification by UK-BCIS Chip score was independently associated with an increased risk of cardiovascular death at 1 year after PCI