Ahmet Baltalarli

Ischaemic preconditioning reduces spinal cord injury in transient ischaemia

Objective — Paraplegia remains a devastating complication after thoracic and thoracoabdominal aortic surgery for coarctations, dissections or aneurysms. Since the advent of ischaemic preconditioning of the myocardium, attention has been directed to the nervous system. This study was designed to evaluate the acute protective effect of ischaemic preconditioning on the spinal cord. Medhods and results — Thirty-six New Zealand white rabbits were randomly assigned to one of three groups.The preconditioning group had 5 minutes of aortic occlusion, 25 minutes reperfusion and 20 minutes of ischaemia, whereas the controls had only 20 minutes of ischaemia.The sham group was anaesthetized and subjected to laparotomy without aortic occlusion. Physiological parameters and somatosensory evoked potentials were monitored during the experiment. Neurological outcome was clinically evaluated up to 48 hour after ischaemia and motor function was scored.Then the animals were sacrificed. Their spinal cord, abdominal aorta and its branches were removed and processed for histopathological examination. Histhopathological changes of the gray matter in the lumbosacral segments were scored from 0 to 6 according to a semi-quantitative scala. The changes in amplitudes of evoked potentials during ischaemia and recovery periods were similar in preconditioning and control groups.The average motor function score was significantly higher in the preconditioning group than the control group at 24 and 48 hours after the ischaemic event (p < 0.05). Histological observations were consistent with the neurological findings.The histopathological scores in the control group and the preconditioning group were 3.2 (1.4-5.2) and 2.4 (0.8-4.4), respectively (p < 0.05). Conclusions — The results suggest that ischaemic preconditioning reduces the spinal cord injury and improves neurological outcome in transient ischaemia in rabbits. This protective mechanism is rapidly invoked within only 25 minutes interval between the preconditioning stimulus and the ischaemic insult.

Systemic and local antibiotic prophylaxis in the prevention of Staphylococcus epidermidis graft infection

BackgroundThe aim of the study was to investigate the in vivo efficacy of local and systemic antibiotic prophylaxis in the prevention of Staphylococcus (S.) epidermidis graft infection in a rat model and to evaluate the bacterial adherence to frequently used prosthetic graft materials.MethodsGraft infections were established in the subcutaneous tissue of 120 male Wistar rats by implantation of Dacron/ePTFE grafts followed by topical inoculation with 2 × 107 CFUs of clinical isolate of methicillin-resistant S. epidermidis. Each of the graft series included a control group, one contaminated group that did not receive any antibiotic prophylaxis, two contaminated groups that received systemic prophylaxis with teicoplanin or levofloxacin and two contaminated groups that received teicoplanin-soaked or levofloxacin-soaked grafts. The grafts were removed 7 days after implantation and evaluated by quantitative culture.ResultsThere was significant bacterial growth inhibition in the groups given systemic or local prophylaxis (P < 0.05). Methicillin-resistant S. epidermidis had greater affinity to Dacron graft when compared with ePTFE graft in the untreated contaminated groups (P < 0.05).ConclusionThe study demonstrated that the usage of systemic or local prophylaxis and preference of ePTFE graft can be useful in reducing the risk of vascular graft infections caused by staphylococcal strains with high levels of resistance.

Preservation of pleural integrity in patients undergoing coronary artery bypass grafting: effect on postoperative bleeding and respiratory function.

Objective —The purpose of this study was to evaluate the influence of preserved integrity of pleura on postoperative bleeding and respiratory function in patients undergoing coronary artery bypass grafting (CABG). Methods and results — Seventy-two CABG patients who received pedunculated IMA graft without opening the pleura (group of intact pleura, group IP) between July 2002 and September 2004 were matched to 72 CABG patients who received pedunculated IMA graft with opened pleura (group of opened pleura, group OP).To match the patients with IP and unique patients with OP, logistic regression was used to develop a propensity score. The C statistic for this model was 0.79. Patients with IP were matched to unique patients with OP with an identical 5-digit propensity score. If this could not be done, we proceeded to a 4-, 3-, 2-, or 1-digit match. Patients characteristics were well matched. There were no differences in preoperative and peroperative variables between the groups. The incidence of postoperative pleural effusion and thoracentesis were significantly lower in group IP than group OP (pleural effusion in 15.2 versus 30.5%; p = 0.029, thoracentesis in 5.5 versus 18.5%; p = 0.036). Other pulmonary complications such as prolonged ventilation, reintubation, pneumothorax, atelectasis, diaphragmatic paralysis were similar in both groups. Patients with IP had significantly lower blood loss (520 versus 870 ml; p < 0.001) and whole blood unit transfusion (26.3 versus 41.6%, p = 0.036). Also, intensive care unit and hospital stay were similar in both groups. Conclusions — Meticulous internal mammary artery harvesting and preservation of the pleural integrity significantly reduces postoperative bleeding and pleural effusion.

Coronary Arterial Revascularization in an Adult with Congenitally Corrected Transposition of Great Arteries and Dextrocardia

Abstract  Objectives:Congenitally corrected transposition of great arteries with dextrocardia is an extremely rare lesion in adulthood. This group of patients does not live long enough for atherosclerotic coronary artery disease processes, because of existing comorbid anomalies. Methods: We report a 47‐year‐old man with isolated congenitally corrected transposition of great arteries, dextrocardia, and athersclerotic coronary artery disease. The patient underwent coronary artery revascularization with cardiopulmonary bypass. The free left internal mammary artery (LIMA) was grafted to the tiny left anterior descending artery (LAD), and the reversed saphenous vein Y graft was anastomosed to the posterior descending and posterolateral branches of the morphologic right coronary artery. Results: The patient recovered uneventfully. He is alive and well 24 months after the surgery. Conclusions: To our knowledge, the present case is the first congenitally corrected transposition of great arteries with dextrocardia treated with grafted coronary artery bypass. Early and full revascularization is very important for the systemic right ventricle exposed to a systemic workload. The vessel pathologies and technical details of this unusual case are discussed in this paper.

Comparison of simultaneous antegrade/vein graft cardioplegia with antegrade cardioplegia for myocardial protection.

Antegrade cardioplegic delivery via the aorta ensures distribution of cardioplegic solution through open arteries, but distribution may not be adequate beyond a stenotic coronary artery. This potential problem can be overcome by direct delivery of cardioplegia via a vein graft. The purpose of this study was to compare simultaneous antegrade/vein graft cardioplegia with antegrade cardioplegia during coronary artery bypass surgery. Twenty patients were divided into 2 groups. In group 1, intermittent antegrade cardioplegia was provided (n=10). In group 2, intermittent antegrade cardioplegia was supplemented by antegrade perfusion of vein grafts after distal anastomoses were completed (n=10). Data on enzyme release and hemodynamics were obtained preoperatively, before the induction of anesthesia, just before cross-clamping, immediately after aortic unclamping, and at 1, 6, 12, 24, and 48 h after unclamping. Enzyme release (creatinine phosphokinase-isoenzyme MB, cardiac troponin I, myoglobin) was similar in both groups (P > .05). Furthermore, no significant difference was noted in the incidence of postoperative low cardiac output syndrome, perioperative myocardial infarction, or ventricular arrhythmia (P > .05). In conclusion, both techniques permitted rapid postoperative recovery of myocardial function. Supplementation of antegrade perfusion of vein grafts with antegrade cold blood cardioplegia offered no advantage to study patients. However, hemostasis of a distal anastomosis may be controlled by this technique.

Surgical treatment of cardiogenic shock due to huge right atrial thromboembolus.

An unusual case is reported of thromboembolus in the right atrium associated with cardiogenic shock and multiple pulmonary micro-embolisms. Two-dimensional echocardiograpy demonstrated a large irregular mass in the right atrium floating freely, prolapsing through the tricuspid valve into the right ventricle during diastole, and leading to inflow and outflow obstruction. An emergency operation was performed and the thromboembolic material was successfully extracted from the right atrium without using cardiopulmonary bypass. This exemplary case highlights the benefit of surgical intervention rather than more conservative approaches such as anticoagulation and/or thrombolysis.

Comparison of the therapeutic efficacy of linezolid and vancomycin and correlation of serum and tissue malondialdehyde and myeloperoxidase in an experimental mediastinitis model.

BACKGROUND We aimed to investigate the therapeutic efficacy of linezolid in an experimental mediastinitis model and to compare it with vancomycin, which is commonly used. The objective of this study was also to evaluate the role of the immune system in mediastinitis. MATERIALS AND METHODS Fifty adult Wistar rats were randomly divided into five groups: an uncontaminated and contaminated untreated control groups; a group that received sefazolin prophylaxis; and two groups treated with vancomycin or linezolid. Median sternotomy without access to pleural spaces was performed on all rats. All groups, except the uncontaminated one, were inoculated with 0.5 mL 10(8) colony-forming units/mL methicillin-resistant Staphylococcus aureus in the mediastinal and sternal layers. Postoperatively, vancomycin and linezolid groups were given antibiotic treatment for 7 d, starting 24 h after the end of the procedure. After 7-d treatment tissue samples from the upper ends of the sternotomy line and mediastinum were obtained and evaluated microbiologically. Additionally, serum, heart, lung, liver, kidney, and mediastinal tissues samples were obtained to determine malondialdehyde (MDA) and myeloperoxidase (MPO). RESULTS The study showed that either vancomycin or linezolid successfully reduced bacterial counts in mediastinum and sternotomy line. MDA and MPO levels were found to be decreased in the treated groups. There was a positive correlation between serum and tissues MDA and MPO in all of the groups. CONCLUSIONS Our study showed that linezolid appears to be a promising option for treating mediastinitis due to methicillin-resistant S. aureus. Additionally, it was demonstrated that a wide inflammatory process occurred after mediastinitis.

Linezolid compared with vancomycin for the prevention of methicillin-resistant Staphylococcus aureus or Staphylococcus epidermidis vascular graft infection in rats: A randomized, controlled, experimental study

BACKGROUND Graft infections are severe complications of vascular surgery that may result in amputation or mortality. Staphylococci are the most frequent cause of vascular graft infections. OBJECTIVE In this study we assessed the prophylactic efficacy of linezolid in comparison with vancomycin in preventing prosthetic vascular graft infection due to methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant Staphylococcus epidermidis (MRSE). METHODS This randomized, controlled, experimental study using healthy adult (aged >5 months) male Wistar rats was conducted in the research laboratory of the Pamukkale University, Denizli, Turkey. The study consisted of an uncontaminated control group and 3 groups for both staphylococcal strains: a contaminated group that did not receive any antibiotic prophylaxis; a contaminated group that received preoperative intraperitoneal (IP) prophylaxis with vancomycin; and a contaminated group that received preoperative IP prophylaxis with linezolid. All rats received a vascular Dacron graft placed inside a subcutaneous pocket created on the right side of the median line. Sterile saline solution (1 mL), to which MRSA or MRSE at a concentration of 2 × 10(7) colony-forming units per milliliter had been added, was inoculated onto the graft surface using a tuberculin syringe to fill the pocket. The grafts were explanted 7 days after implantation and assessed by quantitative culture. RESULTS Seventy rats (mean [SD]weight, 323.7 [17.9]g; mean [SD]age, 5.98 [0.64] months) were evenly divided between the 7 groups. Statistical analysis of the quantitative graft culture suggested that both vancomycin and linezolid were effective in significantly inhibiting bacterial growth when compared with the untreated contaminated groups (all, P < 0.001). However, a statistically significant difference was not observed between the bacteria count in the vancomycin and linezolid prophylaxis groups. When a comparison was made between the bacterial growth in the contaminated control groups, MRSA had significantly greater affinity to the Dacron prostheses than MRSE (all, P < 0.001). CONCLUSION Our study found that linezolid was as effective as vancomycin in suppressing colony counts in MRSA- or MRSE-infected vascular Dacron grafts in rats.

Cerebral protection with trimetazidine in transient brain ischemia in rats

The neuroprotective effect of trimetazidine (TMZ) on ischemic-reperfusion injury was tested by randomized, controlled, prospective study in a rat model of transient global cerebral ischemia. Thirty wistar albino rats were used for study. Animals in TMZ group (n=10) received trimetazidine (3 mg/kg IV bolus) before the occlusion of carotid arteries. A similar volume of saline solution was used in the control group (n=10). The sham group (n=10) were anaesthetized and subjected to operative dissections without vascular occlusion. Physiological parameters, somatosensory evoked potentials (SEPs) were monitored. The neurological outcomes had been clinically evaluated and scored up to 4 days post ischemia. The intergroup differences were compared. Histological observations were clearly correlated with the neurological findings. The percentage of damaged neurons in CA1 and CA3 in subfield of hypochampus 34±6% and 16±6% in the TMZ group, whereas it was 44±5% and 24±5% in the control group (p<0.05). The average neurologic score was significantly better in animals which received TMZ than in the controls at postoperative 24 hours (17.9±1.4 in the TMZ group and 14.9±1.6 in the control group, p<0.05). The results suggest that trimetazidine reduces cerebral injury and preserves neurological function in transient global ischemia in rats.

Neuraminidase produces a decrease of adherence of slime-forming Staphylococcus aureus to gelatin-impregnated polyester fiber graft fabric: an experimental study.

Because slime-forming microorganisms are the major causative agents of graft infections, we aimed to investigate bacterial adherence in slime-forming and nonslime-forming Staphylococcus aureus and to determine the role of neuraminidase (NANase) on adherence to gelatin-impregnated polyester fiber graft fabric. An in vitro model was developed to quantitatively measure bacterial adherence to the surface of the graft. The grafts were divided into two groups – those colonized with slime-forming S. aureus and those colonized with nonslime-forming S. aureus. The grafts were put into sterile tubes and human plasma was instilled and incubated at 37°C to perform fibrin deposition on the grafts. After 48 h of incubation, grafts were drained and inoculated with slime-forming or nonslime-forming S. aureus in triptic soy broth in the presence or absence of NANase. Following 36 h of incubation at 36°C, grafts were vortexed and cultured to perform a colony count. Bacterial counts were expressed as total colony-forming units per square centimeter of graft. Slime-forming S. aureus had greater affinity with the graft compared with nonslime-forming S. aureus (P < 0.05). The adherence of slime-forming S. aureus was impaired by NANase treatment (P < 0.001) but NANase treatment of nonslime-forming S. aureus did not change the adherence to the graft (P > 0.05). These results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming S. aureus can be decreased by NANase treatment. This may have implications for the development of neuraminidase-embedded vascular grafts to diminish biomaterial-related infections.