Encephalopathy and Stroke After Coronary Artery Bypass Grafting

Delayed hyperbaric oxygen therapy for air emboli after open heart surgery: case report and review of a success story

Background

The current case describes a rare diagnosis of iatrogenic air emboli after elective cardiopulmonary bypass that was successfully treated with delayed hyperbaric oxygen therapy, with good clinical evolution in spite of rare complications.

Case presentation

A 35 years old male was admitted to the intensive care unit (ICU) for post-operative management after being placed on cardiopulmonary bypass (CPB) for an elective ventricular septal defect closure and aortic valvuloplasty. The patient initially presented with pathologically late awakening and was extubated 17 h after admission. Neurologic clinical status after extubation showed global aphasia, mental slowness and spatio-temporal disorientation. The injected cerebral CT scan was normal; the EEG was inconclusive (it showed metabolic encephalopathy without epileptic activity); and the cerebral MRI done 48 h after surgery showed multiple small subcortical acute ischemic lesions, mainly on the left fronto- parieto- temporo-occipital lobes. He was taken for hyperbaric oxygen therapy (HOT) over 54 h after cardiac surgery. The first session ended abruptly after 20 min when the patient suffered a generalised tonico-clonic seizure, necessitating a moderately rapid decompression, airway management, and antiepileptic treatment. In total, the patient received 7 HOT sessions over 6 days. He demonstrated full neurological recovery at 4 weeks and GOS (Glasgow Outcome Scale) of 5 out of 5 even after a long delay in initial management. Convulsions are a rare complication of HOT either due to reperfusion syndrome or hyperoxic toxicity and can be managed. Prior imaging by MRI or tympanic paracentesis (myringotomy) should not add further delay of treatment.

Conclusion

HOT should be initiated upon late awakening and/or neurologic symptoms after CPB heart surgery, after exclusion of formal counter-indications, even if the delay exceeds 48 h.

A Successful Endovascular Treatment of an Ischemic Stroke following Cardiac Surgery

Ischemic stroke following cardiac surgery is one of the devastating complications that surgeons may encounter, and may lead to serious disabilities for the patient. The clinical course of such a complication may be prolonged if it is not treated properly. Making a quick decision when choosing a revascularization method is very helpful in this matter. Effective treatment options are usually limited. Neurointerventional maneuvers have recently emerged as a possible therapeutic modality in this field. We present the case of a 52-year-old woman who had open heart surgery in Queen Alia Heart Institute, Jordan, to replace a severely stenotic rheumatic mitral valve and repair a leaking tricuspid valve. Her surgery went smoothly with no major event. However, she developed a massive ischemic stroke during her recovery period despite being on adequate anticoagulation therapy. Urgent radiological work-up confirmed the diagnosis of ischemic stroke in the territory of the right middle cerebral artery. We chose a neuro-interventional method for her treatment, and mechanical thrombectomy was performed with a successful outcome and no apparent complications.

A Successful Endovascular Treatment of an Ischemic Stroke following Cardiac Surgery

Ischemic stroke following cardiac surgery is one of the devastating complications that surgeons may encounter, and may lead to serious disabilities for the patient. The clinical course of such a complication may be prolonged if it is not treated properly. Making a quick decision when choosing a revascularization method is very helpful in this matter. Effective treatment options are usually limited. Neurointerventional maneuvers have recently emerged as a possible therapeutic modality in this field. We present the case of a 52-year-old woman who had open heart surgery in Queen Alia Heart Institute, Jordan, to replace a severely stenotic rheumatic mitral valve and repair a leaking tricuspid valve. Her surgery went smoothly with no major event. However, she developed a massive ischemic stroke during her recovery period despite being on adequate anticoagulation therapy. Urgent radiological work-up confirmed the diagnosis of ischemic stroke in the territory of the right middle cerebral artery. We chose a neuro-interventional method for her treatment, and mechanical thrombectomy was performed with a successful outcome and no apparent complications.

Hyperbaric Oxygen Therapy in the Treatment of Post Cardiac Surgical Strokes – a Case Series and Review of the Literature

Strokes remain an uncommon but significant complication of cardiac surgery. Cerebral air embolism is the likely aetiology in the majority of cases. Hyperbaric oxygen therapy is the recognised treatment for cerebral air embolism associated with compressed air (SCUBA) diving accidents and is therefore also the standard of care for iatrogenic causes of air embolism. It follows that there is a logic in treating post-cardiac surgical stroke patients with hyperbaric oxygen.

The aim of this retrospective review was to examine the outcomes of 12 such patients treated in the Christchurch Hospital hyperbaric unit and to appraise the evidence base for the use of hyperbaric oxygen therapy in this setting.

Despite delays of up to 48 hours following surgery before the institution of hyperbaric oxygen therapy, 10 of the 12 patients made a full neurological recovery or were left with mild residual symptoms, with nine returning to their previous level of care. One patient remained hemiplegic and there was one early neurological death.

There is a paucity of prospective data in this area, but based on sound pathophysiological principles and clinical experience, we believe that patients suffering a stroke following open cardiac surgery should be considered for hyperbaric oxygen therapy.

Statin use and neurologic morbidity after coronary artery bypass grafting: A cohort study

BACKGROUND

Statin use before surgery has been associated with reduced morbidity and mortality after vascular surgery. The effect of preoperative statin use on stroke and encephalopathy after coronary artery bypass grafting (CABG) is unclear.

METHODS

A post hoc analysis was undertaken of a prospectively collected cohort of isolated CABG patients over a 10-year period at a single institution. Primary outcomes were stroke and encephalopathy. Univariable analyses identified risk factors for statin use, which were applied to a propensity score model using logistic regression and patients were divided into quintiles of propensity for statin use. Controlling for propensity score quintile, the odds ratio (OR) of combined stroke and encephalopathy (primary endpoint), cardiovascular mortality, myocardial infarction, and length of stay were compared between statin users and nonusers.

RESULTS

There were 5,121 CABG patients, of whom 2,788 (54%) were taking statin medications preoperatively. Stroke occurred in 166 (3.2%) and encephalopathy in 438 (8.6%), contributing to 604 patients (11.8%) who met the primary endpoint. The unadjusted OR of stroke/encephalopathy in statin users was 1.053 (95% confidence interval [CI] 0.888-1.248, p = 0.582). Adjustment based on propensity score resulted in balance of stroke risk factors among quintiles. The propensity score-adjusted OR of stroke/encephalopathy in statin users was 0.958 (95% CI 0.784-1.170, p = 0.674). There were no significant differences in cardiovascular mortality, myocardial infarction, or length of stay between statin users and otherwise similar nonusers.

CONCLUSIONS

In this large data cohort study, preoperative statin use was not associated with a decreased incidence of stroke and encephalopathy after coronary artery bypass grafting.