Cerebral arterial gas embolism from attempted mechanical thrombectomy: recovery following hyperbaric oxygen therapy

[Complications of mechanical thrombectomy]

CLINICAL PROBLEM

Ischemic stroke is the most common cause of disability in adults and an important disease for society; therefore, the prevention, diagnosis, and treatment play an important role. Endovascular mechanical recanalization to reopen large occlusions of the intracerebral vessels has established itself as the gold standard in therapy, which is why knowledge of the most important complications and their management is essential for interventionalists.

PRACTICAL RECOMMENDATIONS

Intracranial hemorrhages, which include intracerebral and subarachnoid hemorrhages, are dreaded complications that significantly worsen the clinical outcome. Early monitoring and optimal management are therefore essential. Cerebral air embolism is a rare but dangerous complication whose prevention is paramount, as treatment options are limited.

Cerebral air embolism: neurologic manifestations, prognosis, and outcome

Background

Cerebral air embolism (CAE) is an uncommon medical emergency with a potentially fatal course. We have retrospectively analyzed a set of patients treated with CAE at our comprehensive stroke center and a hyperbaric medicine center. An overview of the pathophysiology, causes, diagnosis, and treatment of CAE is provided.

Results

We retrospectively identified 11 patients with cerebral venous and arterial air emboli that highlight the diversity in etiologies, manifestations, and disease courses encountered clinically. Acute-onset stroke syndrome and a progressive impairment of consciousness were the two most common presentations in four patients each (36%). Two patients (18%) suffered from an acute-onset coma, and one (9%) was asymptomatic. Four patients (36%) were treated with hyperbaric oxygen therapy (HBTO), high-flow oxygen therapy without HBOT was started in two patients (18%), two patients (18%) were in critical care at the time of diagnosis and three (27%) received no additional treatment. CAE was fatal in five cases (46%), caused severe disability in two (18%), mild disability in three (27%), and a single patient had no lasting deficit (9%).

Conclusion

Cerebral air embolism is a dangerous condition that necessitates high clinical vigilance. Due to its diverse presentation, the diagnosis can be missed or delayed in critically ill patients and result in long-lasting or fatal neurological complications. Preventative measures and a proper diagnostic and treatment approach reduce CAE's incidence and impact.

Cerebral arterial air emboli on immediate post-endovascular treatment CT are associated with poor short- and long-term clinical outcomes in acute ischaemic stroke patients

PURPOSE

To determine the incidence and predictors of cerebral arterial air emboli (CAAE) on immediate post-endovascular treatment (EVT) dual-energy CT (DECT) in acute ischaemic stroke (AIS) patients, and describe their association with clinical outcomes.

METHODS

EVT records from 2010 to 2019 were screened. Exclusion criteria included intracerebral haemorrhage on post-EVT DECT. In the affected middle cerebral artery (MCA)-territory, circular and linear (length ≥ 1.5*width) CAAE were counted. Clinical data were collected from prospective records. The modified Rankin Scale (mRS) at 90 days was the primary outcome. Multivariable linear, logistic, and ordinal regression were used to analyse the effect of (1) linear CAAE and (2) isolated circular CAAE.

RESULTS

Out of 651 EVT-records, 402 patients were included. In 65 patients (16%), at least one linear CAAE was found in the affected MCA-territory. 17 patients (4%) showed isolated circular CAAE. Multivariable regression showed an association between both the presence and the number of linear CAAE and the mRS at 90 days (presence: adjusted (a)cOR 3.10, 95%CI 1.75-5.50; number: acOR 1.28, 95%CI 1.13-1.44), NIHSS at 24-48 h (presence: aβ 4.15, 95%CI 1.87-6.43; number: aβ 0.88, 95%CI 0.42-1.34), mortality at 90 days (presence: aOR 3.34, 95%CI 1.51-7.40; number: aOR 1.24, 95%CI 1.08-1.43) and stroke progression (presence: aOR 4.01, 95%CI 1.96-8.18; number: aOR 1.31, 95%CI 1.15-1.50). Isolated circular CAAE were not significantly associated with any outcome measure.

CONCLUSION

CAAE were found frequently on post-EVT CT imaging. The presence and the number of linear CAAE, but not circular CAAE, are associated with unfavourable short- and long-term clinical outcomes.

Unusual Histopathological Findings in Mechanically Removed Stroke Thrombi - A Multicenter Experience

Background

Several studies have investigated the histopathology of mechanically retrieved thrombi from stroke patients. Thrombi with unusual components constitute about 1–2% of all stroke thrombi in clinical practice. Knowledge about these rare components is limited.

Objectives

To characterize the histopathology of unusual stroke thrombi from a real-world setting with relation to clinical presentation, patient characteristics and procedural aspects of mechanical thrombectomy.

Methods

One-thousand and eight thrombi retrieved from stroke patients with mechanical thrombectomy at three different hospitals were retrospectively reviewed for unusual histological components. Fifteen thrombi were included in the study for further histopathological analysis. Clinical data and data on procedural aspects were collected.

Results

We identified six cases with large amounts of extracellular DNA, of which three were calcified. All six cases except one received anticoagulant therapy. We describe two types of calcifications that differ with respect to general calcification morphology, von Kossa staining pattern, macrophage immunophenotype and presence of multinucleated giant cells. Cholesterol-rich (n = 3), adipocyte-like pattern-rich (n = 2), collagen-rich (n = 2) and myxomatous (n = 1) thrombi were also identified and are discussed with regard to pathogenesis and clinical and intervention characteristics. Finally, a thrombus with parts of a vascular wall is described. Suggestions for future studies are made and clinical and technical aspects of the management for these rare but important patients are discussed.

Conclusion

In our retrospective multicenter study, we characterized stroke thrombi histopathologically and found subgroups of thrombi defined by presence of rarely seen components. These defined subgroups showed relation to underlying cardiovascular disease, patient characteristics, and mechanical thrombectomy technique. Knowledge about these components may increase our understanding of stroke pathophysiology and influence interventional procedures.

Cerebral catheter angiography and its complications

Catheter-based angiography is an important but invasive procedure in vascular neurology. It is used mainly for diagnosis and for planning treatment in patients with a suspected underlying vascular abnormality. It is often performed as a semiurgent, planned investigation or linked to an interventional procedure. Cerebral angiography provides high-resolution, three-dimensional, pathoanatomical data about the cerebral vasculature and also allows real-time analysis of blood flow. Contrast injections can be repeated to identify subtleties. A physical intervention may also follow angiography. For these reasons, angiography remains the gold standard for delineating vascular lesions of the brain (and spine). Permanent neurological complications are rare, approximately 1%, but become increasingly common in patients aged over 55 years. The main complications are embolic stroke, groin haematoma and contrast-induced nephropathy. In the new era of thrombectomy, it may transpire that other specialists including neurologists may learn to perform the procedure and to manage its complications.