Biomedical subjects

George Asimakopoulos

Publications and source records attributed to George Asimakopoulos.

11 recordsLinked to original sources

PubMed2006

Effects of cell saver autologous blood transfusion on blood loss and homologous blood transfusion requirements in patients undergoing cardiac surgery on- versus off-cardiopulmonary bypass: a randomised trial.

OBJECTIVE: Off-pump CABG is potentially associated with reduced intraoperative blood loss and homologous blood transfusion in comparison to on-pump CABG. In this randomised controlled study we investigated the effects of autologous cell saver blood transfusion on blood loss and homologous blood transfusion requirements in patients undergoing CABG on- versus off-CPB. METHODS: Eighty patients were randomised into one of four groups: (A) on-CPB with cell saver blood transfusion (CSBT), (B) on-CPB without CSBT, (C) off-pump with CSBT and (D) off-pump without CSBT. Volume of intraoperative autologous blood transfusion, postoperative mediastinal blood loss and homologous blood transfusion requirements were measured. Homologous blood was transfused when haemoglobin concentration fell below 8 g/dl postoperatively. Pre- and postoperatively prothrombin time and partial thromboplastin time were measured. RESULTS: Preoperative patient characteristics were well matched among the four groups. The amount of salvaged mediastinal blood available for autologous transfusion was significantly higher in the on-pump group (A) compared to the off-CPB group (C) (433+/-155 ml vs 271+/-144 ml, P=0.001). Volume of homologous blood transfusion was significantly higher in group B vs groups A, C and D (595+/-438 ml vs 179+/-214, 141+/-183 and 230+/-240 ml, respectively, P<0.005). The cell saver groups (A and C) received significantly less homologous blood than the groups without cell saver (160+/-197 ml vs 413+/-394 ml, respectively, P<0.005). Patients undergoing off-CPB surgery received significantly less homologous blood than those undergoing on-CPB CABG irrespective of cell saver blood transfusion (184+/-214 ml vs 382+/-397 ml, P<0.05). Postoperative blood loss was similar in the four groups (842+/-276, 1023+/-291, 869+/-286 and 903+/-315 ml in groups A to D, respectively, P>0.05). Clotting test results revealed no significant difference between the groups. There was no significant difference in postoperative morbidity between groups. CONCLUSION: Off-pump CABG is associated with significant reduction in intraoperative mediastinal blood loss and homologous transfusion requirements. Autologous transfusion of salvaged washed mediastinal blood reduced homologous transfusion significantly in the on-CPB group. Cell saver caused no significant adverse impact on coagulation parameters in on- or off-CPB CABG. Postoperative morbidity and blood loss were not affected by the use of CPB or autologous blood transfusion. We recommend the use of autologous blood transfusion in both on- and off-pump CABG surgery.

Aged↗

PubMed2006

Direct cryosurgery for inoperable metastatic disease of the lung.

A 50-year-old woman presented with dyspnea associated with two isolated metastases in the right lung, which was 1 year after the resection of a primary pleomorphic fibrous histiocytoma from her left thigh. At a planned thoracotomy, the tumor was found to be advanced, contraindicating lobectomy. We aimed to completely destroy the tumor by applying cryosurgery.

Cryosurgery↗

PubMed2006

How safe is it to train residents to perform off-pump coronary artery bypass surgery?

BACKGROUND: The technique of off-pump coronary artery bypass graft (OPCABG) surgery differs considerably from on-pump CABG. This study investigates the impact of surgical training on clinical outcome in patients undergoing OPCABG. METHODS: All 251 OPCABG cases performed by one service over an 18-month period were analyzed. The 83 operations (33%) performed by two trainees under supervision were compared with the 168 operations (67%) performed by an experienced consultant surgeon. Patient and disease characteristics, intraoperative and postoperative data, morbidity and mortality were analyzed using univariate and multivariate analysis. Data were extracted from a prospective database. RESULTS: Patients operated on by the consultant were more likely to have had unstable angina (p = 0.003, odds ratio [OR] = 3.5), impaired left ventricular function (ejection fraction < 0.3; p = 0.005, OR = 2.4), or previous cardiac surgery (p = 0.03). They were more likely to receive three or more grafts (p = 0.017, OR = 2.0). Operative mortality was 2.4% (consultant) and 0% (trainees; p = 0.31). Postoperative morbidity, such as reoperation for bleeding (consultant 3% versus trainees 1.2%), stroke (0.6% versus 1.2%), and hemofiltration (3.6% versus 0%) was similar between the two patient groups. Stay in the intensive care unit was not significantly different in the two groups. CONCLUSIONS: In our experience, trainee surgeons are less likely to operate on patients with unstable angina or cardiac dysfunction. Operative morbidity and mortality are, however, similar in patients operated on by either an experienced consultant surgeon or trainees. We believe OPCABG can be taught safely to trainees under supervision.

Aged↗

PubMed2005

Renal function after cardiac surgery off- versus on-pump coronary artery bypass: analysis using the Cockroft-Gault formula for estimating creatinine clearance.

BACKGROUND: Cardiopulmonary bypass (CPB) is often associated with renal dysfunction, as measured by plasma creatinine levels and hemodialysis rates. This study compared creatinine clearance (CrCl), estimated with the Cockroft and Gault formula, between patients undergoing off-pump coronary artery bypass grafting (OPCAB) versus on-pump CABG (on-CAB). METHODS: Data of 704 consecutive patients were analyzed. Of these patients, 404 underwent OPCAB while 300 had on-CAB. Creatinine clearance, plasma creatinine levels, and clinical outcome were compared between groups. Data between patients who developed new renal impairment, compared to patients with normal postoperative renal function, were also analyzed. RESULTS: Creatinine clearance (preoperative, 74 +/- 25 vs 78 +/- 29 mL/min; day 1, 74 +/- 26 vs 76 +/- 31 mL/min; day 4, 70 +/- 26 vs 72 +/- 29 mL/min) and creatinine levels (preoperative, 99 +/- 25 vs 95 +/- 27 micromol/L; day 1, 101 +/- 29 vs 104 +/- 35 micromol/L; day 4, 110 +/- 44 vs 113 +/- 60 micromol/L), as well as postoperative complications (stroke 1% vs 1%; hemofiltration 1.5% vs 3.7%; death 1.2% vs 2.3%), were overall similar between OPCAB and on-CAB patients. Patients with preoperative CrCl less than 50 mL/min had higher creatinine levels in the on-CAB group on day 1 (p = 0.026), although CrCl was similar between groups. Development of new CrCl less than 50 mL/min postoperatively was associated with higher rates of intraaortic balloon pump insertion, re-sternotomy, hemofiltration, intensive care and hospital stay, without difference between groups. Female sex, low body mass index, high preoperative creatinine levels, and advanced age were associated with deterioration in CrCl. CONCLUSIONS: Currently, the rate of renal impairment is low after both OPCAB and on-CAB. No significant difference in CrCl could be demonstrated between groups. Deterioration in renal function is associated with higher rates of postoperative complications.

Aged↗

PubMed2005

Cryosurgery for malignant endobronchial tumors: analysis of outcome.

STUDY OBJECTIVES: More than 80% of patients with lung cancer are unsuitable for curative surgical treatment. Palliative relief of symptoms, often caused by airway obstruction, is very important. Endobronchial cryosurgery is used for destruction of intraluminal tumors. This study analyzes the effects of cryosurgery on patients with obstructive endobronchial carcinoma. DESIGN: Retrospective analysis of data extracted from a prospective computerized database. SETTING: Tertiary referral thoracic surgical center. PATIENTS: Data of the 172 patients who underwent at least two sessions of endobronchial cryosurgery (group A) were compared with 157 patients who underwent one session of cryosurgery (group B) for malignant primary or metastatic obstructive lung carcinoma over a 5-year period. INTERVENTION: Endobronchial cryosurgery is performed under general anesthesia. A nitrous oxide cryoprobe is inserted through a rigid bronchoscope. The probe achieves a temperature of - 70 degrees C at its tip and is applied to the tumor for two 3-min periods. Statistical analysis assessed the effects of cryosurgery on symptoms, lung function, Karnofsky performance score, and survival. RESULTS: Symptoms of dyspnea, cough, and hemoptysis were significantly reduced in both groups after cryosurgery (p < 0.001), although group A benefited more than group B. Lung function test results improved significantly in group A. The mean Karnofsky performance score (+/- SD) increased from 67 +/- 9 to 74 +/- 10 (group A) and from 67 +/- 10 to 73 +/- 11 (group B). The mean survival was 15 months (median, 11 months) for group A and 8.3 months (median, 6 months) for group B (p = 0.006). Univariate regression analysis showed that no particular patient or tumor characteristic was associated with reduction of symptoms. Patients who had cryosurgery and external beam radiotherapy showed longer survival (p < 0.01). Females and patients with stage IIIa and IIIb tumors achieved significantly improved Karnofsky scores (p < 0.02). Female sex was also a factor for increase in FEV at 1 min (p = 0.003) and FVC (p < 0.001). CONCLUSIONS: Cryosurgery is a safe method for palliation of endobronchial malignancies causing airway obstruction. Statistical analysis showed improvement of dyspnea, cough, and hemoptysis. Cryosurgery can be considered in patients with inoperable obstructive endobronchial carcinoma.

Aged↗

PubMed2004

Monocyte Fc gamma receptor expression in patients undergoing coronary artery bypass grafting.

BACKGROUND: Cardiopulmonary bypass is associated with an inflammatory response with potential deleterious effects. The white cell subpopulation mostly investigated so far is the neutrophil. To date very little has been investigated regarding the role of the monocyte/macrophage. This study focuses on the expression of Fc gamma receptors I, II, and III by monocytes in patients undergoing cardiopulmonary bypass. METHODS: We studied the surface expression of Fc gamma receptors I, II, and III by flow cytometry on gated monocyte subpopulations in the whole blood of adult patients undergoing elective coronary artery bypass grafting. Blood samples were drawn preoperatively and at 15 minutes, 1, 2, 4, 24, 48, and 72 hours, and 6 days postoperatively. A second group of patients undergoing lung resection surgery were studied in a similar fashion. RESULTS: Neither Fc receptor I nor receptor II expression were significantly changed throughout the time points studied. Fc receptor III expression was reduced at 2 and 4 hours (p = 0.016 and 0.002) and increased at 24, 48, and 72 hours after commencement of CPB on a selected subpopulation (15%-35%) of monocytes (p = 0.004, < 0.001, and < 0.001, respectively). This expression returned to preoperative levels by the sixth postoperative day. There were no statistically significant changes in the lung resection group. CONCLUSIONS: Our study demonstrated that cardiopulmonary bypass is associated with a biphasic Fc gamma receptor III expression on a subpopulation of peripheral blood monocytes up to 3 days postoperatively.

Aged↗

PubMed2004

Should the internal thoracic artery be skeletonized?

Traditionally, the internal thoracic artery is harvested as a pedicle. In contemporary cardiac surgical practice, however, certain surgeons practice the internal thoracic artery-skeletonization technique. A systematic review of clinical studies reporting on the use of skeletonized internal thoracic arteries (SKT-ITA) has not yet been performed. The primary aim of this review article is to examine comprehensively the entire body of evidence regarding the use of SKT-ITA. In particular, we aimed to analyze the effects of skeletonization on sternal blood supply, wall damage and blood flow in the harvested vessel, postoperative graft patency, and clinical outcome. Advantages and disadvantages of the skeletonization technique are highlighted and discussed.

Coronary Artery Bypass↗

PubMed2003

Off-Pump Coronary Artery Bypass (OPCAB) surgery reduces risk-stratified morbidity and mortality: a United Kingdom Multi-Center Comparative Analysis of Early Clinical Outcome.

OBJECTIVE: Off-Pump Coronary Artery Bypass (OPCAB) surgery is gaining more popularity worldwide. The aim of this United Kingdom (UK) multi-center study was to assess the early clinical outcome of the OPCAB technique and perform a risk-stratified comparison with the conventional Coronary Artery Bypass Grafting (CABG) using the Cardio-Pulmonary Bypass (CPB) technique. METHODS: Data were collected on 5,163 CPB patients from the database of the National Heart and Lung institute, Imperial College, University of London, and on 2,223 OPCAB patients from eight UK cardiac surgical centers, which run established OPCAB surgery programs. All patients had undergone primary isolated CABG for multi-vessel disease through a midline sternotomy approach, between January 1997 and April 2001. Postoperative morbidity and mortality were compared between the CPB and OPCAB patients after adjusting for case-mix. The mortality of the OPCAB patients was also compared, using risk stratification, to the mortality figures reported by the Society of Cardiothoracic Surgeons of Great Britain and Ireland (SCTS) based on 28,018 patients in the national database who were operated on between January 1996 and December 1999. RESULTS: Morbidity and mortality were significantly lower in the OPCAB patients compared with the CPB patients and the UK national database of CABG patients, over the same period of time, after adjusting for case-mix. CONCLUSIONS: This study demonstrates that risk stratified morbidity and mortality are significantly lower in OPCAB patients than CPB patients and patients in the UK national database.

Adult↗

PubMed2003

A review of anti-inflammatory strategies in cardiac surgery.

It is generally accepted that cardiac surgery is frequently associated with the development of systemic inflammatory response. This phenomenon is very variable clinically, and can be detected by measuring plasma concentrations of certain inflammatory markers. Complement component, cytokines and adhesion molecules are examples of these markers. Systemic inflammation can be potentially damaging to major organs. Several anti-inflammatory strategies have been used in recent years, aiming to attenuate the development of systemic inflammatory response. This article summarizes recently published literature concerning the use of anti-inflammatory techniques and pharmacological agents in cardiac surgery. In particular, the anti-inflammatory effects of off-pump surgery, leukocyte filtration, corticosteroids, aprotinin, phosphodiesterase inhibitors, dpoexamine, H2 antagonists and ACE inhibitors are reviewed. The overall conclusion is that although certain strategies reduce plasma levels of inflammatory mediators, convincing evidence of significant clinical benefits is yet to come.

Adrenal Cortex Hormones↗

PubMed2003

Off-pump coronary artery bypass surgery is associated with reduced neutrophil activation as measured by the expression of CD11b: a prospective randomized study.

BACKGROUND: Coronary artery bypass grafting (CABG) surgery is associated with systemic inflammation. Activation of neutrophils is a crucial step in inflammation and results in neutrophil sequestration within the tissues. One of the potential advantages of performing off-pump coronary artery bypass (OPCAB) surgery is the attenuation of the systemic inflammatory response. This prospective randomized study compares neutrophil activation in patients undergoing OPCAB versus those undergoing CABG with cardiopulmonary bypass (CPB). METHODS: Twenty patients undergoing primary isolated CABG were randomly divided prospectively into 2 groups: 1 group underwent CABG with CPB, and the other group underwent OPCAB. Central venous blood samples were obtained before skin incision and at 15 minutes, 60 minutes, 2 hours, 5 hours, and 24 hours following the initiation of CPB or application of the stabilization device. Differential white cell counts were measured with routine laboratory techniques. CD11b surface expression on neutrophils was measured by flow cytometry. Interleukin 8 levels in the plasma were measured by enzyme-linked immunosorbent assays. RESULTS: The 2 groups were matched with respect to preoperative and operative characteristics. White cell and neutrophil counts rose in both groups following the operation but were significantly higher in the OPCAB group at 5 hours (P < .001 and P = .002, respectively). Interleukin 8 concentrations were significantly higher in the CPB group at 5 hours following the initiation of CPB (P = .034). CD11b levels were significantly higher in the CPB group at 60 minutes (P = .002). CONCLUSION: This prospective randomized study demonstrates that the activation of circulating neutrophils as measured by CD11b expression is lower following OPCAB than in CPB. Although OPCAB is associated with significantly higher neutrophil counts, these neutrophils exhibit fewer activation markers. The lower postoperative neutrophil counts occurring in the CPB group may be explained by the activation and consequent sequestration of the neutrophils in the CPB circuit and tissues.

Aged↗

PubMed2002

The inflammatory response to CPB: the role of leukocyte filtration.

Leukocyte activation is a significant component of the systemic inflammatory response to cardiopulmonary bypass (CPB). Various strategies have been developed aiming to reduce leukocyte activation and its deleterious effects on organ function after cardiac surgery. Leukocyte filtration aims to physically remove activated leukocytes from the circulation during CPB. The technique has been used since the mid-1990s but its efficacy in attenuating the effects of inflammatory response remains controversial. This article presents a review of published trials investigating the effects of leukocyte filtration on humans undergoing cardiac surgery.

Animals↗