Objective There has been substantial improvement of treatment strategies since the creation of Braunwald Classification of unstable angina, yet rare recent evidence exists in terms of the predictive value of Braunwald Classification of unstable angina. We aim to re-evaluate the Braunwald unstable angina (UA) classification on its predictive value of clinical characteristics, angiographic features, and occurrence of future adverse events.
Methods We prospectively included 4508 patients diagnosed with unstable angina presenting for PCI between December, 2012 and December, 2013 in Fuwai hospital. Patients were first divided into three groups according to their Braunwald clinical circumstance of development (A, B or C) (table 1), and then divided into three groups according to their Braunwald Grade of Severity (I, II or III) (table 2). We compared clinical and angiographic features in these groups, and evaluated the 1 year and 2 year incidence of major adverse cerebrocardiovascular events, including all-cause death, myocardial infarction, revascularization, stroke and MACCE composite endpoint event.
Results Respectively, 106, 4346 and 56 patients belong to Braunwald classification of clinical circumstance A, B and C, while 987, 2515 and 1006 patients belong to Braunwald grade of severity I, II and III. Proportion of male, current smoker, previous myocardial infarction, β-blocker usage and presence of chronic total occlusion are significantly different across Braunwald clinical circumstance groups (A, B, C groups) (p<0.05). Proportion of male, current smoker, diabetes, hyperlipidemia, previous myocardial infarction and stroke, β-blocker and calcium channel blocker usage and successful PCI are significantly different across Braunwald grade of severity groups (I, II, III groups) (p<0.05). 2 year event occurrence comparison revealed significant difference in bleeding across A, B, C groups and in myocardial infarction across I, II, III groups (p<0.05). 1 year event occurrence comparison revealed significant stepwise increase in death (0%, 0.9%, 5.4%, p=0.023), in-stent thrombosis (0%, 1.3%, 5.4%, p=0.039) and bleeding (0.9%, 5.9%, 7.1%, p=0.044) across A, B, C groups. After confounding factors adjustment by Cox regression analysis, Braunwald A, B, C groups is independently associated with death (95% CI 2.106 to 22.009, HR 6.808, p=0.001), myocardial infarction (95% CI 1.173 to 7.409, HR 2.948, p=0.022) and in-stent thrombosis (95% CI 1.566 to 13.782, HR 4.646, p=0.006) in 1 year.
Conclusion In our large single-centre prospective Chinese patient cohort, higher Braunwald unstable angina classification is generally associated with worse clinical and angiographic characteristics. Braunwald clinical circumstance classification (A, B, C) is an independent risk factor for death, myocardial infarction and in-stent thrombosis in one year, but not an independent risk factor for these adverse events in 2 years. Braunwald Grade of Severity (I, II, III) is not an independent risk factor for these adverse events in one year and 2 years.
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