Preoperative high leukocyte count: a novel risk factor for stroke after cardiac surgery

Asymptomatic Preoperative Leukocytosis Before Carotid Endarterectomy is Associated With Increased Risk of Stroke: A Study From NSQIP Database

BACKGROUND

Carotid endarterectomy (CEA) is the gold standard operation for treating carotid artery stenosis in patients with symptomatic carotid stenosis of more than 50% and asymptomatic carotid stenosis of more than 80%. Asymptomatic leukocytosis before CEA represents a clinical dilemma for surgeons about the management options. The objectives of this study are to identify the relationship between asymptomatic preoperative leukocytosis and postoperative complications in patients undergoing CEA and to assess the relationship between asymptomatic preoperative leukocytosis and postoperative complications in the cohort of patients with symptomatic carotid stenosis.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database for the years 2011-2019 was utilized for this analysis. Patients with preoperative sepsis, septic shock, pneumonia, wound infections, disseminated cancer, renal failure, and history of chronic steroid use were excluded. The remaining patients were sub-grouped based on white blood cell (WBC) count: Normal WBC (<11k/µL) and High WBC (≥11k/µL). Bivariate analysis between the patient characteristics and preoperative WBC levels was performed following simple and multiple regression analysis. A P-value of <0.05 was set as significant.

RESULTS

Of the 26,332 patients in the study cohort, 7.4% (n =1,946) had preoperative leukocytosis. Patients with preoperative leukocytosis were relatively younger (mean age: 41.5 +/- 9.7 vs 44.3 +/- 9.1; P< 0.001) and more likely to be females (43% vs. 38.5; P< 0.001) than patients with normal WBC count. Patients with preoperative leukocytosis were also more likely to have DM, COPD, a bleeding disorder, be smokers, and be functionally dependent. The analysis revealed that patients with preoperative leukocytosis had a significantly higher rate of stroke, length of stay (LOS)>1- week, acute occlusion or revision, acute renal failure, and return to OR when compared to patients with normal WBC count. Furthermore, patients with high WBC count also experienced higher occurrences of infectious complications, such as wound dehiscence, wound infections, pneumonia, and sepsis. However, there was no difference in the overall 30-day mortality. Multivariate regression analysis showed patients with preoperative leukocytosis had anincreased risk of stroke (AOR 1.5, CI: 1.1-1.9, P = 0.009), LOS>1 week (AOR 1.3, CI: 1.1-1.5, P = 0.003), and return to OR (AOR 1.3, CI: 1.0-1.8, P = 0.030). The increased LOS was especially more pronounced in symptomatic carotid stenosis patients with preoperative leukocytosis. The occurrence of LOS>1 week was 4.91% in asymptomatic stenosis patients with high WBC count compared to 21.5% in symptomatic stenosis patients with high WBC count (P< 0.001).

CONCLUSIONS

Patients with asymptomatic preoperative leukocytosis undergoing CEA have a significantly higher risk of stroke and infectious complications in the postoperative period. Furthermore, patients with symptomatic carotid disease are especially at an increased risk of prolonged LOS. A routine preoperative hematological evaluation may be recommended as a risk assessment tool for patients undergoing CEA, and postponing the elective operation in patients with asymptomatic CEA may be advised unless a thorough preoperative infectious workup is completed.

Preoperative Leukocytosis Among Female Patients Predicts Poor Postoperative Outcomes Following EVAR For Intact Infrarenal AAA

OBJECTIVES

Elevated white blood count (WBC) can be predictive of adverse outcomes following vascular interventions, but the association has not established using multi-institutional data. We evaluated the predictive value of preoperative WBC after endovascular abdominal aortic aneurysm repair (EVAR) for non-ruptured abdominal aortic aneurysms (AAA) in a nationally representative surgical database.

METHODS

Patients with non-ruptured AAA undergoing EVAR were identified in the vascular-targeted National Surgical Quality Improvement Program (NSQIP) database. Baseline characteristics were compared between patients with WBC < 10 K/μL and WBC ≥ 10 K/μL. Multivariable logistic regression analyses were performed to assess the odds of outcomes. The primary outcome was 30-day mortality. Multiple secondary outcomes including length of stay (LOS) > 1 week, 30-day readmission, lower extremity (LE) ischemia, ischemic colitis, myocardial infarction (MI) and others were assessed based on WBC and patient sex.

RESULTS

A total of 10955 patients were included with a mean WBC 7.7 ± 2.7 K/μL. Patients with WBC ≥ 10 K/μL were younger (71.8 ± 9.5 years versus 74.1 ± 8.7 years; P < .001) and were more likely to be diabetic, on steroids, smokers, functionally dependent and presenting emergently (all P ≤ .009). Aneurysm diameter was larger in WBC ≥ 10 K/μL patients (5.9 ± 1.5 cm versus 5.7 ± 1.5 cm; P < .001). Patients with WBC ≥ 10 K/μL had more mortality (2.4% vs 1.3%), LOS > 1 week (13.5% versus 6.7%), 30-day readmissions (9.8% versus 7.3%), LE ischemia (2.3% vs 1.4%), ischemic colitis (1.2% vs 0.5%), and MI (2.0% vs 1.1% ) (all P ≤ .008). Female patients with WBC ≥ 10 K/μL, compared to male patients with WBC ≥ 10 K/μL had more adverse events including mortality, LOS > 1 week, 30-day readmission, LE ischemia (all P ≤ .025). With each incremental increase in WBC by 1K/μL, the adjusted odds ratio of adverse outcomes for all patient was higher (mortality: 1.05 [95% CI, 1.00-1.10], readmission: 1.03 [95% CI, 1.00-1.06], LOS > 1 week: 1.08 [95% CI, 1.05-1.10] and ischemic colitis: 1.11 [95% CI, 1.05-1.16]; all P < .05). The effect was more pronounced in female patients and statistically significant.

CONCLUSIONS

WBC is a predictor of adverse outcomes in patients undergoing EVAR for non-ruptured AAA. After adjusting for associated risk factors, the effect of increasing WBC was more prominent for female patients. Preoperative WBC should be used as a prognostic factor to predict adverse outcomes among EVAR patients.

Implementation of the aortic no-touch technique to reduce stroke after off-pump coronary surgery

OBJECTIVES

Despite substantial scientific effort, the relationship between stroke after coronary artery bypass grafting and the use of the aortic no-touch off-pump technique (anOPCAB) remains incompletely understood. The present study aimed to define the effect of anOPCAB on the occurrence and time point of stroke.

METHODS

A total cohort of 15,042 consecutive patients underwent surgical myocardial revascularization at a single institution. After establishing anOPCAB as routine procedure, 4695 patients received surgery by 18 different surgeons using the anaortic approach. After the exclusion of all patients with cardiogenic shock and "side-clamp" off-pump coronary artery bypass grafting, 13,279 patients (4485 with anOPCAB) were included in the study. Perioperative strokes were classified as strokes occurring during the hospital stay, with early strokes observed immediately after emergence from anesthesia (vs delayed strokes).

RESULTS

The anOPCAB technique reduced the postoperative stroke rate to 0.49% versus 1.31% in on-pump patients (P < .0001). The overall stroke rate after adoption of anOPCAB (0.64%) decreased compared with before its adoption (1.40%; P < .0001). With anOPCAB, the risk of early strokes virtually disappeared to 4 of 4485 patients (0.09%; 95% confidence interval, 0.00-0.18% vs 0.83% in on-pump patients; P < .0001), whereas the incidence of delayed strokes was not affected (0.40% vs 0.48%; P = .5181). The key results were confirmed after adjustment using propensity score-based analyses.

CONCLUSIONS

The anOPCAB technique with avoidance of any aortic manipulation is an effective tool to minimize the risk of early strokes during coronary artery bypass grafting, and thus, should be considered as a routine approach. In contrast, additional preventive strategies against delayed strokes remain to be elaborated.

Contaminating fat in pericardial suction blood: a clinical, technical and scientific challenge

Stroke and diffuse brain damage after cardiac surgery are too common. It is important to find means to reduce the incidence in view of future competition to surgery from less invasive procedures. Stroke is fairly well defined in clinical terms and with several identified mechanisms. Diffuse brain damage is less well defined and more complex in nature. One suggested mechanism is from cerebral fat microembolization of retrieved pericardial suction blood (PSB). The present study aimed to describe a simple method to measure fat content of PSB, how experimental artefacts interfere with the results, and how the unstable character of a fat-blood suspension can be used to design a simple fat-separation system. The quantity of small amounts of fat can be amplified by centrifugation to the tapered tip of a standard glass pipette. The coefficient of variation after repeated experiments was 9.5%. PSB after coronary bypass surgery contained 0.22±0.04% fat of which 15±3% was bound to the surface of the plastic collecting bag. Experimentation requires standardized routines. Static incubation, blood-fat mixing routines, and transfer steps of blood samples between syringes induce substantial artefacts from spontaneous density separation and surface-adhesion of fat. Soya oil is a common reference substance replacing human fat in technical laboratory science, but is associated with artefacts of its own. These artefacts cause problems during experimentation but the oil is a good resource in the design of a simple fat-separation system

Neutrophil Lymphocyte Ratio as a predictor of systemic inflammation - A cross-sectional study in a pre-admission setting

Background: Neutrophil:lymphocyte ratio (NLR)  is an emerging biomarker that is used to predict postoperative mortality and morbidity in cardiac and cancer surgeries. The association of this biomarker with systemic illness and its usefulness in risk assessment of preoperative patients has not been fully elucidated.

Objectives: To determine the prevalence of elevated NLR in preoperative patients and to examine the relationship between elevated NLR and the presence of systemic illnesses as well as anaesthesia risk indices such as American Society of Anesthesia (ASA) and the revised cardiac risk index (RCRI) scores.

  Design: Cross-sectional study

Setting: Anaesthesia pre-admission clinic, Toronto Western Hospital, Toronto, Canada

Patients: We evaluated 1117 pre-operative patients seen at an anesthesia preadmission clinic.

Results: NLR was elevated (>3.3) in 26.6% of target population. In multivariate analysis, congestive cardiac failure, diabetes mellitus and malignancy were independent risk factors predicting raised NLR. After regression analysis, a relationship between NLR and ASA score (Odds Ratio 1.78; 95% CI: 1.42-2.24) and revised cardiac risk index (RCRI, odds ratio 1.33; 95% CI: 1.09-1.64, p-value: 0.0063) was observed.

Conclusions:  NLR was elevated (> 3.3) in 26.6% of patients. Congestive cardiac failure and malignancy were two constant predictors of elevated NLR at >3.3 and > 4.5. There was a strong association between NLR and anesthesia risk scoring tools of ASA and RCRI.

Neutrophil-lymphocyte ratio as predictor of mortality and morbidity in cardiovascular surgery: a systematic review

BACKGROUND

Neutrophil-lymphocyte ratio (NLR) is an emerging biomarker of inflammation and predicts poorer outcome in cancer surgery. The prognostic value of NLR in cardiovascular surgery is unclear.

METHODS

Systematic review and meta-analysis of studies of in cardiovascular surgical patients were conducted to assess the role of perioperative NLR in predicting post-operative mortality and morbidity. Electronic searches were conducted on Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials and Cochrane Database of Systemic Reviews for all prospective clinical studies reporting on NLR and post-operative morbidity and mortality in cardiovascular surgical patient population. Our primary end point was all-cause post-operative mortality and the secondary end point was post-operative morbidity. Mortality outcome from prospective studies were pooled for a meta-analysis using a random-effect model.

RESULTS

Of the 999 citations identified, five studies with 3487 patients met the inclusion criteria. In a pooled analysis of three prospective studies of 3108 patients, a preoperative increase in NLR (>3.3 in cardiac surgery, >5 in vascular surgery) was associated with increased mortality at a mean follow-up of 34.8 months (hazard ratio 1.85, 95% confidence interval 1.46-2.36; P < 0.00001). Raised NLR value was also associated with increased cardiac mortality, amputation in vascular operations and raised risk of post-operative re-intubation.

CONCLUSIONS

Elevated NLR were associated with increased long-term mortality and morbidity after major cardiac and vascular surgery. NLR may guide perioperative management and risk-stratification of patients.

Organ protective mechanisms common to extremes of physiology: a window through hibernation biology

Supply and demand relationships govern survival of animals in the wild and are also key determinants of clinical outcomes in critically ill patients. Most animals' survival strategies focus on the supply side of the equation by pursuing territory and resources, but hibernators are able to anticipate declining availability of nutrients by reducing their energetic needs through the seasonal use of torpor, a reversible state of suppressed metabolic demand and decreased body temperature. Similarly, in clinical medicine the majority of therapeutic interventions to care for critically ill or trauma patients remain focused on elevating physiologic supply above critical thresholds by increasing the main determinants of delivery of oxygen to the tissues (cardiac output, perfusion pressure, hemoglobin concentrations, and oxygen saturation), as well as increasing nutritional support, maintaining euthermia, and other general supportive measures. Techniques, such as induced hypothermia and preconditioning, aimed at diminishing a patient's physiologic requirements as a short-term strategy to match reduced supply and to stabilize their condition, are few and underutilized in clinical settings. Consequently, comparative approaches to understand the mechanistic adaptations that suppress metabolic demand and alter metabolic use of fuel as well as the application of concepts gleaned from studies of hibernation, to the care of critically ill and injured patients could create novel opportunities to improve outcomes in intensive care and perioperative medicine.

Association of total white cell count with mortality and major adverse events in patients with peripheral arterial disease: a systematic review

OBJECTIVES

Peripheral arterial disease (PAD) is principally caused by atherosclerosis, an established inflammatory disease. Total white cell count (TWCC) is a marker of inflammation and has been associated with outcomes for patients with inflammatory diseases. The aim of this systematic review was to assess the association of TWCC with mortality and major adverse events (MAEs) in PAD patients.

METHODS

Studies investigating the association of TWCC with outcome in patients with PAD were identified by a literature search using the Medline and Cochrane databases. To be eligible for inclusion, studies needed to investigate the association of TWCC with mortality or a composite endpoint that included mortality in patients with PAD. Studies were excluded when the primary focus was carotid artery disease, aortic aneurysmal disease, intracranial vascular disease, or rheumatoid arthritis and treatment with chemotherapy or transplantation of stem cells. Secondary searching of reference lists and relevant reviews was performed.

RESULTS

Ten studies including 8,490 patients with PAD met the inclusion criteria. All studies investigated more than 100 patients with four studies assessing more than 1,000 patients. Study quality varied with well-established risk factors of outcome such as age, smoking, diabetes, and the ankle brachial index being adjusted for inconsistently. The study populations were also disparate. Few studies reported relative risk and 95% confidence intervals for the association of TWCC with mortality or MAE. TWCC was positively and significantly associated with death alone in four of five studies investigating 3,387 patients. TWCC was positively and significantly associated with MAE in five of six studies investigating a total of 6,846 patients.

CONCLUSIONS

Current evidence suggests a positive association of TWCC with mortality and MAEs in patients with PAD. Further well-designed prospective studies are required with high-quality analysis and more complete reporting of outcomes.

Perioperative stroke: risk assessment, prevention and treatment

OPINION STATEMENT

Numerous risk factors for perioperative stroke have been identified and many are modifiable. Surgical patients with a history of cerebrovascular disease should be evaluated by a neurologist. Cardiac and cerebrovascular testing is critical in identifying patients at high risk for perioperative stroke. The identification and treatment of carotid disease in the context of upcoming surgery has been a source of controversy. Routine carotid revascularization performed with coronary artery bypass graft (CABG) surgery for incidentally discovered carotid stenosis is not recommended. Prior to aortic manipulation during CABG, epiaortic ultrasound should be performed to identify aortic atheromatous plaques. If possible, preoperative aspirin, beta blocker, statin, and angiotensin converting-enzyme (ACE) inhibitor therapy should be continued in the perioperative period. Patients who are prescribed anticoagulation at high risk of thromboembolism should receive bridging anticoagulation during the perioperative period. The identification and prevention of postoperative atrial fibrillation (AF) is central to stroke prevention. CABG patients should be initiated on beta blockade +/- amiodarone to prevent postoperative AF. Many practitioners have been traditionally nihilistic towards acute perioperative stroke treatment. Given the narrow therapeutic window of treatment options, candidacy is dependent on timely recognition. Intravenous and endovascular thrombolysis/therapies are viable options in selected patients under the guidance and expertise of a neurologist. This article will present the epidemiology of perioperative stroke, the pathophysiology, risk assessment and stratification for common surgeries. The article will additionally focus on treatment options including modifiable risk factor reduction and the perioperative management of medications.

What is the exact predictive role of preoperative white blood cell count for new-onset atrial fibrillation following open heart surgery?

Background:

Atrial fibrillation (AF) occurs in 30% patients on the second or third day post operation; therefore, it is the most prevalent and complicated arrhythmia after open heart surgery. White blood cell (WBC) count seems to be most significantly associated with cardiovascular disorders. This study was designed to evaluate the exact relationship between preoperative WBC count and post-Coronary artery bypass graft (CABG) AF in patients with severe left ventricle (LV) dysfunction who underwent elective off-pump coronary artery bypass.

Methods:

This study was conducted on 104 patients from among 400 patients with severe LV dysfunction undergoing elective off-pump CABG surgery from February 2011 to February 2012, in Afshar Cardiovascular Center, Yazd, Iran. Patients with emergency surgery, unstable angina creatinine higher than 2.0 mg/dL, malignancy, or immunosuppressive disease were excluded. Preoperative serological tests of the participants, such as WBC counts, were saved in their medical dossiers. Of the 400 patients undergoing CABG, AF was found in 54 cases; these 54 male patients formed the experimental group and 60 other patients in the intensive care unit (ICU) and hospital stay without postoperative AF were part of the control group.

Results:

The average age of the patients was 68.5±12.8 years. WBC counts in patients with and without AF three days before surgery were 12,340±155 and 8,950±170, respectively. On surgical day, WBC counts in the patients with and without AF were 13,188±140 and 9,145±255, respectively (P value three days before surgery: 0.04; P value on surgical day: 0.01). Of the 54 male patients with postoperative AF (POAF), duration of AF was more in cases with elevated WBC count (12,000-14,000) than in those with lower elevated WBC count (10,000-12,000) (]P=0.025), but there was no relationship between frequency of recurrence of AF and grading of elevation of WBC count (]P=0.81).

Conclusion:

These findings show that three days before surgery and on surgery day, there was a difference in WBC count between both groups. So, preoperative WBC count may predict the incidence and duration of AF; however, it cannot be a predictor of the frequency of recurrence of AF. Finally, WBC count is an independent marker for POAF and duration of AF.

Process Review of a Departmental Change from Conventional Coronary Artery Bypass Grafting to Totally Arterial Coronary Artery Bypass and Its Effects on the Incidence and Severity of Postoperative Stroke

Background: We evaluated the process of changing from conventional coronary artery bypass grafting (CABG) to totally arterial off-pump coronary artery bypass (TOPCAB) at a single heart center in Germany.Methods: We (1) used multivariate statistical methods to assess real-time monitoring of OPCAB effects, (2) conducted a case review to assess preventable deaths and identify areas of improvement, (3) conducted a team survey, and (4) evaluated benchmarking results.Results: All surgeons and assistants (n = 18) at this center were involved and were guided by the department head and one of the consultants, who was trained in this procedure in 2004 at the Leuven OPCAB school. The frequency of OPCAB operations increased abruptly in 2005 from 5% to 43% and then increased gradually to 67% (n = 546) by 2008 (total, 1781 OPCAB cases and 1563 on-pump cases). The in-hospital and 30-day mortality rates for OPCAB surgeries (n = 10 [0.6%] and 21 [1.2%], respectively) were lower than for on-pump surgeries (n = 27 [1.7%] and 26 [1.7%], respectively). Stroke rates were also lower for OPCAB surgeries (7 cases [0.4%] versus 15 cases [1%]). The lower risk of stroke in the OPCAB group was significant (P < .05) after risk adjustment. Monitoring curves and case reviews demonstrated a preventable death percentage of at least 30%. The attitude of the team was mostly positive because of the promising results (eg, fewer strokes, increasing TOPCAB popularity, and a top national rank).Conclusions: The change from conventional CABG to TOPCAB was effective in decreasing the incidence and severity of stroke, in developing a team routine and a positive team attitude, and in producing excellent benchmarking results. The presence of a training and communication deficiency at the beginning of the study suggested an area for further improvement. After 6 years TOPCAB had largely replaced conventional CABG.

Panvascular inflammation and mechanisms of injury in perioperative CNS outcomes

In this review, the evidence for inflammatory processes as being of fundamental importance in end-organ dysfunction- specifically stroke and neurocognitive impairment in patients undergoing cardiac surgery-will be reviewed. The risk of central nervous system (CNS) impairment following an off-pump cardiac surgery will be contrasted with that of patients undergoing percutaneous coronary intervention (PCI) or medical management, and the role of progression of underlying cerebrovascular disease and, in particular, panvascular inflammation as an accompaniment to unstable angina with attendant risk of stroke will be explored. In addition, the various roles of preoperative comorbidities, aortic atheroma, and the use of selective avoidance of aortic instrumentation as well as carotid endarterectomy as risk modification strategies will be evaluated. Finally, a summary of recommendations for strategies to decrease risk of perioperative CNS impairment will be presented.

Immature circulating neutrophils in sepsis have impaired phagocytosis and calcium signaling

Patients with sepsis commonly develop leukocytosis, which is presumed to reflect a host response to infection. Effective phagocytosis by neutrophils is crucial in the clearance of invading microbes. However, efficacy of phagocytosis in sepsis is controversial. We hypothesized that host phagocytic capacity in sepsis can be affected by immature neutrophils that are released into the circulation. Circulating neutrophils were evaluated in 16 patients with severe sepsis and 5 healthy donors. Immature neutrophils were identified by the cell morphology. Phagocytosis was evaluated by micromanipulation technique and simultaneous cytosolic-free Ca2+ imaging. Leukocytosis was present in 12 of 16 patients. Nine of the 12 patients with leukocytosis and 3 of 4 patients with normal white blood cell counts had increased circulating immature neutrophils (mean, 39.3% +/- 20.7%; normal <or=5%). Quantification of the phagocytic activity revealed a significantly reduced phagocytic index of immature neutrophils as compared with mature neutrophils from both sepsis patients and healthy donors (25% +/- 5% vs. 69% +/- 8% and 42% +/- 6%; P < 0.05). As compared with mature neutrophils, the number of internalized zymosan particles within immature neutrophils was also significantly lower. Mature neutrophils from patients and healthy donors displayed a single rapid transient Ca signal during phagocytosis in contrast with weak signals from immature neutrophils. Our preliminary results show that phagocytic capacity of immature neutrophils is lower as compared with mature neutrophils. An increase in immature neutrophils in severe sepsis may undermine the overall phagocytic efficacy of a host despite observed leukocytosis.

Cerebrovascular accidents in patients with a ventricular assist device

OBJECTIVE

A cerebrovascular accident is a devastating adverse event in a patient with a ventricular assist device. The goal was to clarify the risk factors for cerebrovascular accident.

METHODS

Prospectively collected data, including medical history, ventricular assist device type, white blood cell count, thrombelastogram, and infection, were reviewed retrospectively in 124 patients.

RESULTS

Thirty-one patients (25%) had 48 cerebrovascular accidents. The mean ventricular assist device support period was 228 and 89 days in patients with and without cerebrovascular accidents, respectively (P < .0001). Sixty-six percent of cerebrovascular accidents occurred within 4 months after implantation. Actuarial freedom from cerebrovascular accident at 6 months was 75%, 64%, 63%, and 33% with the HeartMate device (Thoratec Corp, Pleasanton, Calif), Thoratec biventricular ventricular assist device (Thoratec Corp), Thoratec left ventricular assist device (Thoratec), and Novacor device (WorldHeart, Oakland, Calif), respectively. Twenty cerebrovascular accidents (42%) occurred in patients with infections. The mean white blood cell count at the cerebrovascular accident was greater than the normal range in patients with infection (12,900/mm3) and without infection (9500/mm3). The mean maximum amplitude of the thrombelastogram in the presence of infection (63.6 mm) was higher than that in the absence of infection (60.7 mm) (P = .0309).

CONCLUSIONS

The risk of cerebrovascular accident increases with a longer ventricular assist device support period. Infection may activate platelet function and predispose the patient to a cerebrovascular accident. An elevation of the white blood cell count may also exacerbate the risk of cerebrovascular accident even in patients without infection. Selection of device type, prevention of infection, and meticulous control of anticoagulation are key to preventing cerebrovascular accident.

Relationship between white cell count, neuropsychologic outcome, and microemboli in 161 patients undergoing coronary artery bypass surgery

OBJECTIVE

Neuropsychologic impairment remains a problem after coronary artery bypass grafting. Relatively few studies have examined the potential role of the perioperative inflammatory response. This study aimed to determine whether there was any association between perioperative white cell count, microemboli, and cognitive performance after surgical intervention.

METHODS

White cell count and differential were prospectively measured perioperatively in 161 patients undergoing coronary artery bypass grafting. A neuropsychologic test battery (9 tests) was administered preoperatively and 6 to 8 weeks postoperatively in all 161 patients. Cerebral microemboli during cardiopulmonary bypass were also recorded by means of a transcranial Doppler scan of the right middle cerebral artery.

RESULTS

There was no correlation between microemboli and white cell counts at any time point. There were weak but significant inverse correlations between both preoperative (r = -0.19, P = .02) and postoperative (r = -0.21, P < .01) white cell count and a measure of overall neuropsychologic test performance (total z change score). There was a weak but significant positive correlation between the neutrophil count 10 minutes after bypass and the intraoperative microemboli count (r = 0.23, P = .01).

CONCLUSIONS

The correlation between white cell count and neuropsychologic outcome suggests that an inflammatory response might have a role in determining cognitive outcome after coronary artery surgery with cardiopulmonary bypass. The positive correlation between the microemboli during cardiopulmonary bypass and the neutrophil count 10 minutes after bypass is compatible with microemboli contributing to the inflammatory response. The patients' preoperative inflammatory status might also be predictive of the response to surgical intervention.

[Should we avoid cardiopulmonary bypass with diabetic patients?]

In the peri-operative and post-operative course of coronary bypass operations, the diabetic patient is susceptible to complications that cause morbidity and mortality. Morbidity might best be conceptualized as the cumulative effect of the diabetic patient chronically at risk and a variety of surgically related insults, including surgical stress, anaesthesia, hypo- and hypertension, anaemia, dysrhythmias, de- or hyperhydration and cardiopulmonary bypass (CPB) that exceed the compensatory capacities of the patient. Because all these factors for adverse outcome coexist, it becomes difficult to determine which ones are most important. However, it is reasonable that, in the presence of generalized atherosclerosis affecting the aorta ascendens, carotids and the cerebral arteries, the interaction of CPB-associated embolization, hypoperfusion and inflammation may cause neurologic morbidity. Many physiologic alterations (such as non-pulsatile perfusion and hemodilution) occur during CPB and may worsen renal dysfunction in patients with diabetic nephropathy. Pulmonary dysfunctions, associated with diabetic microangiopathy, could be unmasked by atelectasis, capillary leak and other pathophysiological conditions developing after the use of extracorporeal circulation. Actually, there is evidence that with the avoidance of CBP and the use of adequate OPCAB (Off Pump Coronary Artery Bypass) techniques, by experienced teams, the incidences of neurological, renal and pulmonary complications decrease, in high-risk patients, e. g. diabetics, as well as in unselected cohorts. Because it is not possible to identify confidently those patients who are at risk for CPB-associated complications, we use a strategy where all CABG (Coronary Artery Bypass Grafting) are performed in OPCAB technique. The total OPCAB approach will in addition ascertain the development of organizational OPCAB routines and expertise. The process of re-engineering the unit towards total OPCAB needs systematic training and re-training of cardiac surgeons by surgeons, experienced in both, OPCAB surgery and knowledge transfer, according to the principles of continuing medical education (CME). Thus, the chances of the OPCAB technique improving the outcome of diabetic patients can be fully realized.

Preoperative White Blood Cell Count is Independently Associated With Higher Perioperative Cardiac Enzyme Release and Increased 1-Year Mortality After Coronary Artery Bypass Grafting

BACKGROUND

Elevated preprocedural systemic markers of inflammation, including white blood cell count, have been associated with adverse clinical outcomes after percutaneous coronary intervention. The relationship between preoperative white blood cell count and clinical outcomes after coronary artery bypass grafting is less clear despite increasing evidence that neutrophils participate in reperfusion injury. We sought to determine the relationship between preoperative white blood cell count and in hospital major morbidity and 1-year survival after coronary artery bypass grafting.

METHODS

We prospectively studied 3,024 consecutive isolated coronary artery bypass graft procedures. Preoperative white blood cell count was determined by automated counter, perioperative cardiac enzyme release by the creatine kinase-myocardial band isoenzyme, and all-cause mortality over the first postoperative year taken from a national death registry. Multivariate logistic regression and Cox proportional hazards analyses were performed.

RESULTS

Preoperative white blood cell count offered as a continuous variable and as five predetermined groups was independently associated with cardiac enzyme release three or more times the upper limit of the reference range (adjusted odds ratio = 1.5 per 10 x 10(9)/L increase, 95% confidence interval: 1.2 to 2.0, p = 0.002) and higher 1-year mortality (adjusted hazard ratio = 1.6 per 10 x 10(9)/L increase, 95% confidence interval: 1.2 to 2.1, p < 0.001).

CONCLUSIONS

Higher preoperative white blood cell count is independently associated with higher perioperative myonecrosis and 1-year mortality after coronary artery bypass grafting.

White blood cell count and the incidence of ischemic stroke in coronary heart disease patients

PURPOSE

White blood cell (WBC) count is a marker of inflammation and has been associated with the development of cardiovascular disease. We investigated the relationship between WBC counts and the incidence of ischemic cerebrovascular disease in a large cohort of patients with pre-existing atherothrombotic disease and defined blood lipid boundaries.

SUBJECTS AND METHODS

We followed up patients with documented coronary heart disease for 4.8 to 8.1 years. An extensive medical evaluation, conducted at baseline, included assessment of vascular risk factors and measures of blood lipids. Among 5435 patients with WBC counts, free of stroke, 295 developed an ischemic cerebrovascular disease (fatal and nonfatal). After review of available medical records, 186 of these cases had ischemic stroke or TIA.

RESULTS

Higher WBC counts were associated with increased risk for ischemic cerebrovascular disease. Age-adjusted hazard ratio (HR) was 1.55 with 95% confidence interval (CI) 1.16-2.07, upper WBC tertile compared with the lowest. Adjusting for clinical covariates, WBC count remained an independent predictor for ischemic cerebrovascular disease (HR = 1.39; 95% CI 1.03-1.87, upper WBC tertile compared with the lowest). A similar trend appeared for the endpoint of ischemic stroke/transient ischemic attack (TIA). Further adjustment for plasma fibrinogen did not change the association materially (HR = 1.32; 95% CI 1.01-1.80; upper tertile of WBC compared with lowest).

CONCLUSIONS

These findings support the role of WBC count as a simple inexpensive and readily available marker for risk stratification of ischemic cerebrovascular disease among patients with pre-existing atherothrombotic disease and defined blood lipid boundaries.

Leukocytosis and ischemic vascular disease morbidity and mortality: is it time to intervene?

The association between leukocytosis and increased morbidity and mortality of ischemic vascular disease has been observed for more than half a century, and recent studies in >350,000 patients confirm the robustness of the association and the dramatically higher relative and absolute acute and chronic mortality rates in patients with high versus low leukocyte counts. Although there is reason to believe that the association is not causal (that is, that leukocytosis is simply a marker of inflammation), there is also reason to believe that the leukocytosis directly enhances acute thrombosis and chronic atherosclerosis. Leukocytosis also is associated with poor prognosis and vaso-occlusive events in patients with sickle cell disease, and experimental data suggest a direct role for leukocytes in microvascular obstruction. The only way to test whether leukocytes contribute directly to poor outcome in ischemic cardiovascular disease is to assess the effect of modifying leukocyte function or number. Because selective blockade of leukocyte integrin alphaMbeta2 and P-selectin have thus far been disappointing as therapeutic strategies in human cardiovascular and cerebrovascular disease, I discuss the potential risks and benefits of short-term treatment with hydroxyurea to decrease the leukocyte count in select populations of patients at the highest risk of short-term death.