Risk factor analysis of early and delayed cerebral complications after cardiac surgery

Hypotension after intensive care unit drop-off in adult cardiac surgery patients

BACKGROUND

Hypotension is a frequent complication in the intensive care unit (ICU) after adult cardiac surgery.

AIM

To describe frequency of hypotension in the ICU following adult cardiac surgery and its relation to the hospital outcomes.

METHODS

A retrospective study of post-cardiac adult surgical patients at a tertiary academic medical center in a two-year period. We abstracted baseline demographics, comorbidities, and all pertinent clinical variables. The primary predictor variable was the development of hypotension within the first 30 min upon arrival to the ICU from the operating room (OR). The primary outcome was hospital mortality, and other outcomes included duration of mechanical ventilation (MV) in hours, and ICU and hospital length of stay in days.

RESULTS

Of 417 patients, more than half (54%) experienced hypotension within 30 min upon arrival to the ICU. Presence of OR hypotension immediately prior to ICU transfer was significantly associated with ICU hypotension (odds ratio = 1.9; 95% confidence interval: 1.21-2.98; P < 0.006). ICU hypotensive patients had longer MV, 5 (interquartile ranges 3, 15) vs 4 h (interquartile ranges 3, 6), P = 0.012. The patients who received vasopressor boluses (n = 212) were more likely to experience ICU drop-off hypotension (odds ratio = 1.45, 95% confidence interval: 0.98-2.13; P = 0.062), and they experienced longer MV, ICU and hospital length of stay (P < 0.001, for all).

CONCLUSION

Hypotension upon anesthesia-to-ICU drop-off is more frequent than previously reported and may be associated with adverse clinical outcomes.

Early Versus Delayed Stroke After Cardiac Surgery: A Systematic Review and Meta-Analysis

Background

Although it is traditionally regarded as a single entity, perioperative stroke comprises 2 separate phenomena (early/intraoperative and delayed/postoperative stroke). We aimed to systematically evaluate incidence, risk factors, and clinical outcome of early and delayed stroke after cardiac surgery.

Methods and Results

A systematic review (MEDLINE, EMBASE, Cochrane Library) was performed to identify all articles reporting early (on awakening from anesthesia) and delayed (after normal awakening from anesthesia) stroke after cardiac surgery. End points were pooled event rates of stroke and operative mortality and incident rate of late mortality. Thirty‐six articles were included (174 969 patients). The pooled event rate for early stroke was 0.98% (95% CI 0.79% to 1.23%) and was 0.93% for delayed stoke (95% CI 0.77% to 1.11%; P=0.68). The pooled event rate of operative mortality was 28.8% (95% CI 17.6% to 43.4%) for early and 17.9% (95% CI 14.0% to 22.7%) for delayed stroke, compared with 2.4% (95% CI 1.9% to 3.1%) for patients without stroke (P<0.001 for early versus delayed, and for perioperative stroke, early stroke, and delayed stroke versus no stroke). At a mean follow‐up of 8.25 years, the incident rate of late mortality was 11.7% (95% CI 7.5% to 18.3%) for early and 9.4% (95% CI 5.9% to 14.9%) for delayed stroke, compared with 3.4% (95% CI 2.4% to 4.8%) in patients with no stroke. Meta‐regression demonstrated that off‐pump was inversely associated with early stroke (β=−0.009, P=0.01), whereas previous stroke (β=0.02, P<0.001) was associated with delayed stroke.

Conclusions

Early and delayed stroke after cardiac surgery have different risk factors and impacts on operative mortality as well as on long‐term survival.

Coronary artery bypass grafting and paraparesis; is there a correlation?

Adult cardiac surgery is associated with significant perioperative morbidity and mortality rates, mainly in elderly patients with co-morbidities. A series of postoperative complications may arise and delay the recovery of patients undergoing cardiac surgery. Such complications also increase the burden of resource use and may affect late survival rates. Neurological complications appear mainly as stroke of varying degrees, with impairment of mobility and ability of the patient. We describe a rare case of progressive paraparesis after on-pump coronary artery bypass grafting, and review its aetiology, diagnosis and management.

Does Gender Influence the Likelihood or Types of Complications Following Cardiac Surgery?

Over 410,000 cardiac surgeries are performed in American women each year. Women having coronary artery bypass graft (CABG) and valve surgery do so at an older age and with more cardiovascular risk factors than men. Women's smaller body size may also increase risk by increasing the technical difficulty of surgical procedures. Female CABG patients appear to have higher perioperative mortality and cardiac morbidity, although studies of neurologic outcomes in female CABG patients have produced equivocal findings. Women undergoing CABG tend to consume more hospital resources than men do in terms of blood transfusion, mechanical ventilation, and length of intensive care unit and overall hospital stay. With regard to valve surgery, women appear to have worse outcomes than men if the surgery is combined with a CABG operation. Women and men undergoing isolated aortic valve surgery have similar mortality, but little is known about gender differences in mitral and tricuspid valve surgery outcomes. Women who require heart transplantation tend to have idiopathic cardiomyopathy rather than the ischemic cardiomyopathy that is more common in male heart transplant candidates. Although female heart transplant recipients seem to have a stronger immunologic response after transplantation, which manifests in more frequent acute rejection episodes, it is not clear whether this increases women's mortality risk. Men appear to have a greater incidence of posttransplant vasculopathy than women. Further research is needed to identify risk factors for perioperative morbidity and mortality in women undergoing cardiac surgery and to develop medical interventions to mitigate these risks.

Progressive Paraparesis after CABG Surgery

CABG is one of the most common cardiac surgeries all over the world. Similar to other surgeries, it may be associated with some undesirable complications including neurologic complications which might cause morbidity and mortality after surgery. We will describe a case of Progressive Paraparesis after CABG Surgery and review its etiology, diagnosis and management.

[Neurological complications in cardiac surgery post-operative period]

The incidence of neurological complications after cardiac surgery continues to be elevated, although this is variable in the different studies published, fundamentally because of the different populations studied and the different definitions of neurological dysfunction. The etiology of these alterations is attributed to a multifactorial origin, aortic artherosclerosis, cerebral hypoperfusion and inflammatory phenomenon secondary to the technique. This review arises from the recognition of the personal, economic, and socio-health care repercussion entailed by these complications, with high rates of mortality and morbidity recorded, and it tries to give an objective view of the current literature on the subject. Having knowledge of the risk markers and understanding the pathogenesis is important to try to plan strategies that may minimize the appearance and development of these complications and contribute to the decrease of their serious consequences. The data and the experience obtained by our group are shown at the end of the review.

Effects of cardiopulmonary bypass on neurocognitive performance and cytokine release in old and diabetic rats

BACKGROUND

Age and diabetes mellitus have been identified as independent risk factors for cognitive decline after cardiac surgery with cardiopulmonary bypass (CPB). We tested the effects of CPB on cognitive function in aged and diabetic rats utilizing the Morris water maze (MWM).

METHODS

Aged rats (26 months) were randomized into a sham group (cannulation but no CPB, n = 11) and a 90 min CPB group (n = 11). In addition, young rats (n = 14) were made diabetic with streptozotocin 9 weeks before experimentation and randomized to a sham or 90 min CPB group. Cytokine release [interleukin (IL-6)] and short-term MWM performance (days 8-14 after operation) were assessed in all animals. Long-term MWM performance (8 weeks after operation) was assessed in aged rats only.

RESULTS

There were no differences between the aged groups in short-term (P = 0.58) or long-term MWM performances (P = 0.69). The diabetic animals also showed no differences between the sham and CPB groups in MWM performance (P = 0.64). IL-6 assays showed an increased inflammatory response after CPB in the diabetic animals, but not in the elderly groups.

CONCLUSIONS

Ninety minutes of normothermic CPB had no deleterious effect on neurocognitive outcome in elderly or chronically diabetic animals, suggesting that CPB in itself is not a sufficient stressor of the rat central nervous system.

Cerebrovascular accidents after cardiac surgery: an analysis of CT scans in relation to clinical symptoms

There is a link between aortic manipulation, particle embolization, and cerebrovascular accidents (CVA) in cardiac surgery. The present aim was to study hemispheric side differences of CVA. Cardiac-surgery patients with CVA and with computer tomography (CT) performed (n = 77) were analyzed within a total group of 2641 consecutive cases. CT data were reviewed for hemispheric and vascular distribution, and compared with CVA-symptom data of immediate and delayed type. Of the included patients, 66% had positive CT. In the group of 'cardiac-type' operations (e.g., routine clamping and cannulation) and having immediate CVA, right-hemispheric lesions were more frequent than of the contra-lateral side (p = 0.005). Patients with aortic dissections had strong dominance of bilateral findings, which was different from the unilateral pattern of 'cardiac-type' operations (p = 0.001). The middle-cerebral artery territory dominated, and when involved showed a significant (p = 0.022) right-sided distribution. Both CT and clinical symptoms confirmed that CVA after cardiac surgery has a right-hemispheric predominance. These observations may imply that aortic manipulation directs embolic material towards the brachiocephalic trunk.

Canonical Correlation Analysis of Risk Factors and Clinical Outcomes in Cardiac Surgery

Assessment of the association between risk factors and outcomes in cardiac surgery is a complex problem. The aim of this study was to explore the relationship between possible risk factors and several clinical outcomes in cardiac surgery by using canonical correlation analysis (CCA). This retrospective study of 2605 consecutive adult patients who underwent cardiac surgery, evaluated 74 potential risk factors and up to 12 outcomes by canonical correlation analysis. For three serious outcomes, sternal wound complications/mediastinitis, cerebral complications, and perioperative myocardial infarctions, CCA was preceded by univariate analyses and backward stepwise multivariate logistic regression analyses. The CCA suggests that the major risk factors for complications in these models are intraoperative and postoperative risk factors. The power of risk prediction models developed with multivariate regression analysis can be enhanced by application of canonical correlation analysis, thereby offering new ways of analyzing and interpreting sets of potential risk factors in relation to sets of clinical outcomes.

Atherosclerosis of the ascending aorta as a major determinant of the outcome of cardiac surgery

Epiaortic ultrasonography has high sensitivity for the detection of atherosclerosis. In several studies, the technique has identified atherosclerosis of the ascending aorta as the major risk factor for stroke after cardiac surgery. The level of risk depends on the presence, location and extent of disease when the ascending aorta is surgically manipulated. This knowledge enables clinicians to focus on the diagnostic and surgical technique and to consider the various options. Routine use of intraoperative epiaortic ultrasonography should be applied so that surgical manipulation of the ascending aorta can be reduced or, if possible, avoided in patients with atherosclerosis of the ascending aorta. Alternatively, if major manipulation such as clamping must be performed in the presence of severe atherosclerosis, the use of intra-aortic filters could be considered.