Topography and functional connectivity analysis of heart surgery-associated brain lesions: a literature review
Clinical Snapshot
PICO Framework
| P — Population | Adult patients who developed ischemic brain lesions following cardiac surgery, identified through case reports with available neuroimaging data |
| I — Intervention | Cardiac surgery (any type) as the precipitating exposure, with subsequent lesion topography mapping and lesion network mapping (LNM) using normative resting-state functional connectivity data |
| C — Comparator | Ischemic stroke lesions from the ATLAS database, matched for hemispheric involvement |
| O — Outcomes | Arterial territory involvement, voxel-level lesion topography, and patterns of functional disconnection (occipital lobes, posterior thalamus including pulvinar, medial frontal cortex) |
Bottom Line
This systematic review of 20 case reports applies lesion topography mapping and lesion network mapping to characterise the neuroanatomical signature of cardiac surgery-associated ischemic brain injury. The principal finding — that post-cardiac surgery lesions preferentially involve posterior arterial territories, particularly occipital PCA branches and the posterior thalamus (pulvinar), with associated functional disconnection extending to the medial frontal cortex — is biologically plausible and clinically interesting. The pulvinar's role in attentional gating and the medial frontal cortex's involvement in executive function align with the cognitive profile often observed in postoperative cognitive dysfunction. However, the evidence base of 20 case reports is profoundly limited by publication bias, an unknown denominator, absence of clinical outcome correlation, and lack of formal quality appraisal. These findings are strictly hypothesis-generating and should not alter current clinical practice. They provide a valuable neuroanatomical framework to guide the design of prospective neuroimaging studies in cardiac surgery cohorts. Senior clinicians should interpret these results as an early signal warranting validation in adequately powered, prospective studies with standardised neuroimaging and neuropsychological outcome measures.
Key Findings
P Value: Permutation-based statistical analyses with correction for multiple comparisons applied; specific p-values not reported in the abstract
Effect Size: Not quantified as a conventional effect size (e.g., odds ratio or Cohen's d) in the abstract; results expressed as voxel-level topographic differences and arterial territory frequencies from permutation-based analyses
Primary Outcome: Post-cardiac surgery ischemic lesions more frequently involve posterior arterial territories — specifically occipital branches of the posterior cerebral arteries and posterior thalamic regions — compared with ATLAS database stroke controls matched for hemispheric involvement
Nnt Or Sensitivity: Not applicable in this context; no NNT, sensitivity, specificity, or hazard ratio reported. The study is descriptive-topographic rather than therapeutic or diagnostic in design
Confidence Interval: Not reported in the abstract; permutation-based p-values with multiple comparison correction are the primary inferential statistics
Clinical Application
The lesion network mapping methodology used in this study is a research tool not currently available in routine clinical practice. However, the topographic findings — if validated in larger prospective cohorts — could inform targeted neuropsychological assessment batteries focusing on visuospatial, attentional (pulvinar-mediated), and executive (medial frontal) domains in post-cardiac surgery patients. In Australia, cardiac surgery is performed across major public and private hospital centres, with approximately 30,000 open-heart procedures annually. Postoperative neurological complications, including stroke and postoperative cognitive dysfunction (POCD), are recognised complications managed under RACGP and ANZCA perioperative guidelines. The TGA has approved several neuroprotective monitoring devices (e.g., cerebral oximetry) for intraoperative use, though no specific pharmacological neuroprotective agent is PBS-listed for this indication. The findings of this review, if replicated, could support the case for posterior-territory-focused neuroimaging protocols and neuropsychological screening tools in Australian cardiac surgery follow-up pathways. RACGP guidelines on postoperative cognitive assessment do not currently specify territory-based imaging protocols, representing a potential area for guideline development pending higher-quality evidence. Adult patients undergoing cardiac surgery who subsequently develop neurological symptoms or cognitive decline, particularly where posterior cortical or thalamic dysfunction is suspected. The findings are most relevant to neurologists, neuropsychologists, and cardiac surgeons managing postoperative neurological complications.
Abstract
BACKGROUND: Cardiac surgery is a major therapeutic advancement but remains associated with neurological complications, including ischemic stroke and postoperative cognitive decline. Compared with stroke of other etiologies, ischemic brain injury following cardiac surgery may involve distinct vascular territories and functional networks, potentially influencing its characteristic cognitive profile. METHODS: We performed a systematic review of case reports describing ischemic brain lesions occurring after cardiac surgery in adults with available neuroimaging data. Lesions were manually traced onto a standard brain atlas and compared with ischemic stroke lesions from the ATLAS database, matched for hemispheric involvement. Lesion topography was analyzed at the arterial territory and voxel levels. Lesion network mapping was conducted using normative resting-state functional connectivity data to identify patterns of functional disconnection. Permutation-based statistical analyses were applied, with correction for multiple comparisons and lesion volume included as a covariate. RESULTS: Nineteen articles met the inclusion criteria, yielding 20 cases of post-cardiac surgery ischemic lesions. Compared with stroke controls, these lesions more frequently involved posterior arterial territories, particularly the occipital branches of the posterior cerebral arteries and posterior thalamic regions. Lesion network mapping revealed a distinct pattern of functional disconnection in the occipital lobes, posterior thalamus (including the pulvinar), and medial frontal cortex. CONCLUSIONS: Our results suggest that ischemia associated with cardiac surgery may preferentially involve posterior arterial territories and be associated with distinct patterns of functional disconnection involving the occipital lobe, the pulvinar, and the medial frontal cortex.
References
- 1.Marcolongo, F., Guariglia, C., Tessari, G., Tropea, A., Volterrani, M., & Alves, P. N. (2026). Topography and functional connectivity analysis of heart surgery-associated brain lesions: a literature review. Neurological Sciences: Official Journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology. https://doi.org/10.1093/brain/aww288
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