Petros Tzimas

Postoperative levels of cardiac troponin versus CK-MB and high-sensitivity C-reactive protein for the prediction of 1-year cardiovascular outcome in patients undergoing vascular surgery

ObjectiveThis study evaluated comparatively the predictive value of postoperative cardiac troponin I (cTnI), creatinine kinase (CK)-MB, and high-sensitivity C-reactive protein (hs-CRP) in 1-year cardiovascular mortality and morbidity in patients undergoing elective vascular surgery. MethodsA total of 295 consecutive patients undergoing elective noncardiac vascular surgery were prospectively followed-up over a period of 12 months. The levels of cTnI, CK-MB, and hs-CRP were measured preoperatively and 24 h after operation. The primary endpoint was the composite of cardiovascular death, nonfatal acute myocardial infarction, ischemic stroke, and unstable angina. ResultsThe primary endpoints occurred in 11 patients (3.8%). Receiver operating characteristic curve analysis showed that postoperative cTnI was a strong predictor of a cardiovascular event during 1-year follow-up (area under the curve, 0.852; P<0.001). Areas under the curve for hs-CRP and for CK-MB were 0.734 (P=0.008) and 0.494 (P=0.947). A threshold cTnI value of 0.4 ng/ml was highly associated with the occurrence of a cardiovascular event, with a sensitivity of 80% and specificity of 81%. Furthermore, cTnI levels provided a significantly better prediction than CK-MB levels (P=0.009) and tended to be superior to hs-CRP (P=0.2). ConclusionPostoperative cTnI levels seem to be superior to CK-MB and hs-CRP levels for the prediction of 1-year cardiovascular mortality and morbidity in patients undergoing elective vascular surgery.

Association Between Serum γ-Glutamyltransferase and Acute Ischemic Nonembolic Stroke in Elderly Subjects

BACKGROUND AND AIMS Elevated serum gamma-glutamyltransferase (GGT) levels have been proposed as an independent predictor for cardiovascular morbidity and mortality. The aim of this study was to determine whether GGT levels are associated with acute ischemic/nonembolic stroke in a case-control study of elderly subjects. METHODS A total of 163 patients >70 years of age (88 men) admitted due to a first-ever acute ischemic/nonembolic stroke and 166 volunteers (87 men) without a history of cardiovascular disease were included. The association between GGT and stroke was determined by multivariate logistic regression modelling after adjusting for potential confounding factors. RESULTS GGT levels were higher in subjects with metabolic syndrome (MetS) and correlated with MetS individual components including insulin resistance. Stroke patients showed higher concentrations of GGT compared with controls. In univariate analysis, crude odds ratio (OR) for GGT was 1.06/1 IU/L increase (95% CI, 1.03-1.09; p<0.001). Compared to subjects with GGT levels in the lowest quartile, those within the highest quartile had a 4.7-times increase in the odds of experiencing an ischemic stroke (95% CI 2.39-9.11, p<0.001). This association remained significant after controlling for all potential confounders (adjusted OR, 2.90, 95% CI, 1.35-6.27; p=0.007). Analysis of interaction between MetS and GGT showed that subjects with MetS had a 1.08 higher odds/1 IU/L increase in GGT to experience an ischemic stroke [adjusted OR, 1.08 (95% CI, 1.04-1.12; p<0.001). CONCLUSIONS There are positive associations between serum GGT and first ischemic/nonembolic stroke in individuals >70 years of age independent of established risk factors for cardiovascular disease and concurrent metabolic abnormalities.

Impact of metabolic syndrome in surgical patients: should we bother?

Clinicians inevitably encounter patients who meet the diagnostic criteria for the metabolic syndrome (MetS); these criteria include central obesity, hypertension, atherogenic dyslipidaemia, and hyperglycaemia. Regardless of the variations in its definition, MetS may be associated with adverse outcomes in patients undergoing both cardiac and non-cardiac surgery. There is a paucity of data concerning the anaesthetic management of patients with MetS, and only a few observational (mainly retrospective) studies have investigated the association of MetS with perioperative outcomes. In this narrative review, we consider the impact of MetS on the occurrence of perioperative adverse events after cardiac and non-cardiac surgery. Metabolic syndrome has been associated with higher rates of cardiovascular, pulmonary, and renal perioperative events and wound infections compared with patients with a non-MetS profile. Metabolic syndrome has also been related to increased health service costs, prolonged hospital stay, and a greater need for posthospitalization care. Therefore, physicians should be able to recognize the MetS in the perioperative period in order to formulate management strategies that may modify any perianaesthetic and surgical risk. However, further research is needed in this field.

Cerebral oximetry values in dialyzed surgical patients: a comparison between hemodialysis and peritoneal dialysis

Abstract Background: Cerebral tissue regional oxygen saturation (rSO2) through near-infrared spectroscopy (NIRS) is a method for non-invasive monitoring of cerebral tissue oxygenation. However, nowadays there is limited information on the level of cerebral tissue oxygenation in dialyzed end-stage renal disease (ESRD) surgical patients. The aim of this observational study was to evaluate the baseline cerebral rSO2 values, to compare values between hemodialysis (HD) and peritoneal dialysis (PD) patients and identify risk factors that could predict cerebral tissue oxygenation in these patients. Patients/Methods: Thirty-two ESRD patients (≥18 years old), scheduled to undergo elective minor or major surgery, were enrolled. Patients were allocated in two groups according to dialysis modality. Twenty-three patients were treated with HD and nine were treated with PD. Demographic and clinical characteristics, comorbidities and arterial hemoglobin oxygen saturation (SpO2) of the study population were recorded. Results: Patients who were treated with HD had significant lower baseline rSO2 values compared with PD patients [median, 50% (28–63) vs. 63% (45–69), p = 0.002]. Hierarchical linear regression model analysis showed that preoperative Hb and SpO2 were positive predictive variables (B = 0.353, p = 0.01 and B = 0.375, p = 0.009, respectively) for rSO2. Moreover, dialysis modality was independent predictor for baseline rSO2. The modality of dialysis remained an independent predictor for rSO2 after controlling for the other significant variables (B = 0.291, p = 0.032) and PD was associated with higher baseline values of rSO2. Conclusion: In conclusion, ESRD surgical patients undergoing PD treatment appear to have significantly higher baseline cerebral tissue saturation values compared with HD.

Intravenous levosimendan-norepinephrine combination during off-pump coronary artery bypass grafting in a hemodialysis patient with severe myocardial dysfunction

This the case of a 63 year-old man with end-stage renal disease (on chronic hemodialysis), unstable angina and significantly impaired myocardial contractility with low left ventricular ejection fraction, who underwent off-pump one vessel coronary bypass surgery. Combined continuous levosimendan and norepinephrine infusion (at 0.07 μg/kg/min and 0.05 μg/kg/min respectively) started immediately after anesthesia induction and continued for 24 hours. The levosimendan/norepinephrine combination helped maintain an appropriate hemodynamic profile, thereby contributing to uneventful completion of surgery and postoperative hemodynamic stability. Although levosimendan is considered contraindicated in ESRD patients, this case report suggests that combined perioperative levosimendan/norepinephrine administration can be useful in carefully selected hemodialysis patients with impaired myocardial contractility and ongoing myocardial ischemia, who undergo off-pump myocardial revascularization surgery.

Minimum r-Star Cover of Class-3 Orthogonal Polygons

We are interested in the problem of covering simple orthogonal polygons with the minimum number of r-stars; an orthogonal polygon is an r-star if it is star-shaped. The problem has been considered by Worman and Keil [13] who described an algorithm running in \(O(n^{17} \hbox {poly-log}\, n)\) time where n is the size of the input polygon.

Huge Interatrial Septal Aneurysm: A Coincidental but Rather Fatal Finding

We report the case of a patient with a huge interatrial septal aneurysm as an intraoperative coincidental finding that led to a fatal outcome. The patient was admitted to our hospital in order to undergo elective coronary artery bypass grafting because he suffered from severe coronary artery disease. We intraoperatively diagnosed by transesophageal echocardiography a huge interatrial septal aneurysm mimicking a right atrial tumor. The aneurysm was initially resected and then coronary artery bypass grafting was successfully performed but the patient never achieved a successful separation from cardiopulmonary bypass probably because of massive embolic events.

Relationship between normal preoperative white blood cell count and major adverse events after endovascular repair for abdominal aortic aneurysm: results of a pilot study

STUDY OBJECTIVE To examine the association between preoperative white blood cell (WBC) count within the reference range and major adverse events (MAEs) following endovascular repair of abdominal aortic aneurysms (AAA). DESIGN Prospective observational study. SETTING Vascular surgery clinic in a tertiary university hospital. PATIENTS One hundred fifty-three consecutive patients. INTERVENTION Endovascular repair of AAA. MEASUREMENTS All patients had normal preoperative WBC count (3.5-10.3 K/μL). Postoperative MAE was defined as death, stroke, and myocardial infarction. The prognostic value of preoperative WBC was determined by receiver operating characteristic curves, whereas χ2 test and Cochran-Armitage trend test were used to assess the association between MAE and different values of WBC. MAIN RESULTS A preoperative WBC cutoff value of 7.3 Κ/μL could predict MAE with 62% sensitivity and 62% specificity (area under the curve, 0.62). Patients with higher preoperative WBC experienced more events compared with patients with lower values (P=.027). A linear relationship was observed between an increasing preoperative WBC count within the reference range and the risk of postoperative events (P=.004). Logistic regression analysis showed that preoperative normal WBC count was an independent predictor of MAE and revealed that for every 1-K/μL increase, patients had a 32.8% increase in their relative odds of developing postoperative MAE (P=.035). CONCLUSIONS This pilot study demonstrates a linear correlation between an increasing preoperative WBC count within the reference range and an increased risk for postoperative MAEs following endovascular repair for AAA. Identification of high-risk patients at an early stage by using WBC count could prove useful in implementing measures to improve their clinical outcome.