Impaired renal function is related to deep and mixed, but not strictly lobar cerebral microbleeds in patients with ischaemic stroke and TIA

The vasculature of the brain and kidneys are similarly vulnerable to hypertension, so their microvascular damage may be correlated. We investigated the relationship of renal function to the anatomical distribution of cerebral microbleeds (CMBs), a marker of underlying cerebral small vessel disease (hypertensive arteriopathy or cerebral amyloid angiopathy), in a Western patient cohort. This was a retrospective study of referrals to a hospital stroke service. All patients with clinical data and a T2*-weighted gradient-recalled echo (T2*-GRE) MRI were included. MRI scans were rated for CMBs using the Microbleed Anatomical Rating Scale. Renal function was assessed by estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease formula. We included 202 patients, 39 with CMBs (19.3 %); 15 had “strictly lobar”, 12 had “strictly deep” and 12 had “mixed” CMBs. Patients without CMBs had a higher eGFR than those with CMBs (mean difference 6.50 ml/min/1.73 m², 95 % CI −14.73 to 1.72 ml/min/1.73 m², p = 0.121). Multivariable analysis found that those with deep and mixed CMBs had a lower eGFR than those without CMBs (mean difference −10.70 ml/min/1.73 m², 95 % CI −20.35 to −1.06 ml/min/1.73 m², p = 0.030). There was no difference in eGFR found between those with strictly lobar CMBs and those without CMBs (mean difference −1.59 ml/min/1.73 m², 95 % CI −13.08 to 9.89 ml/min/1.73 m², p = 0.79). In a Western patient cohort, there appears to be an association between eGFR and the presence of deep and mixed CMBs, but not strictly lobar CMBs. This suggests a shared vulnerability of renal afferent and cerebral deep and superficial perforating arterioles to systemic hypertension. The arteriopathy underlying strictly lobar CMBs (i.e. cerebral amyloid angiopathy), appears to be less related to renal impairment.