Risk factors for perioperative ischemic stroke in cardiac surgery

Protective effects on acute hypoxic-ischemic brain damage in mfat-1 transgenic mice by alleviating neuroinflammation

Acute hypoxic-ischemic brain damage (HIBD) mainly occurs in adults as a result of perioperative cardiac arrest and asphyxia. The benefits of n-3 polyunsaturated fatty acids (n-3 PUFAs) in maintaining brain growth and development are well documented. However, possible protective targets and underlying mechanisms of mfat-1 mice on HIBD require further investigation. The mfat-1 transgenic mice exhibited protective effects on HIBD, as indicated by reduced infarct range and improved neurobehavioral defects. RNA-seq analysis showed that multiple pathways and targets were involved in this process, with the anti-inflammatory pathway as the most significant. This study has shown for the first time that mfat-1 has protective effects on HIBD in mice. Activation of a G protein-coupled receptor 120 (GPR120)-related anti-inflammatory pathway may be associated with perioperative and postoperative complications, thus innovating clinical intervention strategy may potentially benefit patients with HIBD.

Flow analysis during mock circulation in normal and aortic arch aneurysm models through an aortic cannula toward the aortic arch and root

The aim of this study was to elucidate flow patterns of two different types of aortic cannulas inserted from the ascending aorta toward the aortic arch and root by mock circulation in a normal aortic arch and an aortic arch aneurysm model. Extracorporeal circulation was established using a centrifugal pump, a transparent glass normal aortic arch model, and an aortic arch aneurysm model for measurement by particle image velocimetry. The Stealthflow and Dispersion cannulas were used to elucidate the characteristics of the flow pattern and velocity under the condition of the cannula tip toward the aortic arch and aortic root. In the normal aortic arch model, high-velocity exit flow ranging from 0.7 to 0.8 m/s was detected in the proximal aortic arch by directing the cannula tip toward the aortic arch, whereas flow velocity in the aortic arch was < 0.2 m/s by directing the cannula tip toward the aortic root. In the aortic arch aneurysm model, high-velocity exit flow ranging from 0.5 to 0.8 m/s was detected in the aortic arch by directing the cannula tip toward the aortic arch, whereas flow velocity in the aortic arch was decreased to less than 0.2 m/s by directing the cannula tip toward the aortic root. Directing the aortic cannula tip toward the aortic root allowed the high-velocity exit flow to attenuate in velocity, so that flow velocity in the aortic arch was sufficiently reduced by reversed flow and vortex formation in both the normal and aortic arch aneurysm models.

Prevalence of Carotid Stenosis and Incidence of Ischemic Stroke in Patients Undergoing Non-Coronary Cardiac Surgery

Introduction

Many publications on coronary surgery and carotid stenosis (CS) can be found, but we do not have enough information about the relationship between ischemic stroke, CS and non-coronary cardiac surgery.

Objectives

To evaluate the incidence and risk factors associated with the stroke and CS ≥50% in patients undergoing non-coronary surgeries.

Objectives

We assessed 241 patients, aged 40 years or older, between 2009 and 2016, operated in Santa Casa de Misericórdia de Ponta Grossa-PR, Brazil. We perform carotid Doppler in patients 40 years of age or older before any cardiac surgery as a routine. The incidence and possible risk factors for CS ≥50% and perioperative stroke were analyzed by univariate statistical analysis.

Results

11 patients (4.56%) presented perioperative stroke. The risk factor for stroke was CS ≥50%: OR=5.3750 (1.2909-22.3805), P=0.0208. Eighteen patients (7.46%) had CS ≥50% and their risk factors were extracardiac arteriopathy: OR=18.6607 (6.3644-54.7143), P<0.0001; COPD: OR=3.9040 (1.4491-10.5179), P=0.0071; diabetes mellitus: OR=2.9844 (1.0453-8.5204), P=0.0411; recent myocardial infarction: OR=13.8125 (1.8239-104.6052), P=0.0110; EuroSCORE II higher P=0.0056.

Conclusion

The incidences of stroke and CS ≥50% were 4.56% and 7.46%, respectively. The risk factor for stroke was CS ≥50% and for CS ≥50% were extracardiac arteriopathy, COPD, diabetes mellitus, recent myocardial infarction and higher EuroSCORE II.

Consequence of Ischemic Stroke after Coronary Surgery with Cardiopulmonary Bypass According to Stroke Subtypes

Introduction

The aim of this study was to determine the outcomes of patients developing ischemic stroke after coronary artery bypass grafting (CABG).

Methods

From March 2012 to January 2017, 5380 consecutive patients undergoing elective coronary surgery were analyzed. Ninety-five patients who developed ischemic strokes after on-pump coronary surgery were included in the study, retrospectively. The cohort was divided into four subgroups [total anterior circulation infarction (TACI), partial anterior circulation infarction (PACI), posterior circulation infarction (POCI), and lacunar infarction (LACI)] according to the Oxfordshire Community Stroke Project (OCSP) classification. The primary endpoints were in-hospital mortality, total mortality, and survival analysis over an average of 30 months of follow-up. The secondary endpoints were the extent of disability and dependency according to modified Rankin Scale (mRS).

Results

The incidence of stroke was 1.76% (n=95). The median age was 62.03±10.06 years and 68 (71.6%) patients were male. The groups were as follows: TACI (n=17, 17.9%), PACI (n=47, 49.5%), POCI (n=20, 21.1%), and LACI (n=11, 11.6%). Twenty-eight (29.5%) patients died in hospital and 34 (35.8%) deaths occurred. The overall mortality rate of the TACI group was significantly higher than that of the LACI group (64.7% vs. 27.3%, P=0.041). The mean mRS score of the TACI group was significantly higher than that of the other groups (P=0.003).

Conclusion

Patients in the TACI group had higher in-hospital and cumulative mortality rates and higher mRS scores. We believe that use of the OCSP classification and the mRS may render it possible to predict the outcomes of stroke after coronary surgery.

Neuroprotection against stroke and encephalopathy after cardiac surgery

Cerebral ischemia in the perioperative period is a major risk factor for stroke, encephalopathy, and cognitive decline after cardiothoracic surgery. After coronary artery bypass grafting, both stroke and encephalopathy can result in poor patient outcomes and increased mortality. Neuroprotection aims to lessen the severity and occurrence of further injury mediated by stroke and encephalopathy and to aid the recovery of conditions already present. Several pharmacological and non-pharmacological methods of neuroprotection have been investigated in experimental studies and in animal models, and, although some have shown effectiveness in protection of the central nervous system, for most, clinical research is lacking or did not show the expected results. This review summarizes the value and need for neuroprotection in the context of cardiothoracic surgery and examines the use and effectiveness of several agents and methods with an emphasis on clinical trials and clinically relevant neuroprotectants.

Distribution of perioperative stroke in cardiac surgery

Background and purpose

The recent literature suggests that a cardiac origin in ischaemic stroke is more frequent than previously assumed. However, it is not always clear which patients benefit from additional cardiac investigations if obvious cardiac pathology is absent.

Methods

A single‐center retrospective observational study was performed with 7454 consecutive patients admitted to the intensive care unit after cardiac surgery in the period 2006–2015 and who had postoperative brain imaging. Cerebral imaging was studied for the occurrence of stroke including subtype and involved vascular territory. It was assumed that all perioperative thromboembolic strokes are of cardiac origin. Data obtained from a hospital cohort of consecutive patients who received a diagnosis of ischaemic stroke were used for comparison.

Results

Thromboembolic stroke occurred in 135 cardiac surgery patients in 56 (41%) of whom the posterior cerebral circulation was involved. In the control group, 100 out of 503 strokes (20%) were located in the posterior cerebral circulation. The relative risk for a posterior location for stroke after cardiac surgery compared to patients with ischaemic stroke without prior cardiac surgery was 2.09; 95% confidence interval 1.60–2.72.

Conclusions

Thromboembolic stroke after cardiac surgery occurs twice as often in the posterior cerebral circulation compared to ischaemic strokes in the general population. If confirmed in general stroke cohorts, the consequence of this finding may be that in patients with an ischaemic stroke that involves the posterior cerebral circulation the chance of a cardiac origin is increased and therefore might trigger additional cardiac investigations such as long‐term heart rhythm monitoring or echocardiography.

Mechanical Thrombectomy for Acute Ischemic Stroke After Cardiac Surgery

Ischemic stroke is a rare yet devastating complication that may occur following cardiothoracic surgery. Fibrinolytic treatment is contraindicated due to elevated risk for hemorrhage. Mechanical thrombectomy entails a catheterized approach wherein the thrombus is physically removed from the vessel without the use of fibrinolytics, minimizing the possibility of intracranial hemorrhage. Here, we present two original cases of mechanical thrombectomy as treatment for patients experiencing emergent large vessel occlusion following cardiothoracic surgery. A literature review was conducted to determine current treatment guidelines, risk factors, and complications resulting from recanalization due to mechanical thrombectomy versus fibrinolytic therapy. One patient was admitted due to chronic, American College of Cardiology/American Heart Association stage D, New York Heart Association functional class IV heart failure and required complete, artificial hemodynamic support for two weeks and on the 19^th day experienced neurologic decline secondary to a supraclinoid left internal carotid artery (ICA) occlusion. Mechanical thrombectomy resulted in distal reperfusion and neurologic improvement. The second patient presented with coronary artery disease and underwent triple coronary artery bypass grafting and endovein harvesting. On post-operative day 2, the patient experienced a left ICA occlusion extending to the cavernous ICA resulting in speech impairment and right-sided weakness. The patient was heparinized and underwent mechanical thrombectomy, resulting in immediate speech and muscle strength recovery. Medical advances allow mechanical thrombectomy to be performed in a timely and effective manner at specialized treatment centers. It offers endovascular treatment modalities to a unique patient population with postoperative stroke. In such patients, thrombectomy can safely provide reperfusion while reducing the risk of complications associated with conventional thrombolytics.