This is a very large retrospective study. As expected, the authors find that hypertension is highly prevalent in patients with ischemic stroke (over 70% of patients in their registry had hypertension). They also find an association between HTN and stroke recurrence. After controlling for various factors, they only find solid evidence of the relationship with small vessel disease and not with other subtypes. This is important because in order to address stroke recurrence we need to tackle the risk factors responsible for that. But when interpreting this finding we need to remember that this was a retrospective study.
Prospective trials such as WASID and SAMPRIS have clearly found an association between hypertension control and lower stroke recurrence. The current study provides some food for thought: ischemic stroke is a heterogeneous disease with heterogeneous risk factors and in order to address recurrence we need to concentrate on specific risk factors for that stroke sub-type. It also makes a case for investigating ischemic stroke cause thoroughly as that might help differentiate the stroke sub-type leading to change in the management.