To investigate risk factors for early neurological deterioration (END) following intravenous thrombolysis in patients with branch atheromatous disease (BAD)-related stroke and to develop and validate a predictive nomogram.

We retrospectively analyzed data from 263 patients with BAD-related stroke who received intravenous thrombolysis at the Department of Neurology, Shengli Oilfield Central Hospital (Dongying, Shandong Province) between January 2016 and December 2024. Patients were divided into END (n=104) and non-END (n=159) groups based on the occurrence of END. LASSO regression was used to identify factors associated with END, which were then used to construct a risk nomogram using the R software.

Significant differences were found between the END and non-END groups in terms of responsible vessels distribution, infarct location, fasting blood glucose level on the following day, pre-thrombolysis National Institute of Health stroke scale (NIHSS) score, and the muscle strength score of the pre-thrombolysis NIHSS score (all P<0.05). Multivariate logistic regression identified infarct location in the pons [OR=10.438, 95%CI: 3.286–38.495, variance inflation factor (VIF) value=1.083], fasting blood glucose level on the following day (OR=1.248, 95%CI: 1.072–1.475, VIF value=1.022), and muscle strength score of the pre-thrombolysis NIHSS score (OR=1.201, 95%CI: 1.014–1.429, VIF value=1.067) as independent risk factors for END (P<0.05). The predictive nomogram based on the independent risk factors and internally validated through bootstrapping showed good calibration, and strong predictive performance, with an area under the ROC curve of 0.896 (95%CI: 0.850–0.943).

Pontine infarction, elevated next-day fasting blood glucose, and muscle strength score of the pre-thrombolysis NIHSS score are independent risk factors for END after intravenous thrombolysis in patients with BAD-related stroke. The constructed nomogram provides a clinically useful tool for predicting END with high accuracy.