Sahin Iscan

Dynamic alterations in cerebral, celiac and renal flows resulting from ascending aorta, subclavian artery and femoral artery cannulations of extracorporeal devices

Introduction: The aim of this study was to assess the relationships among cardiac output, extracorporeal blood flow, cannulation site, right (RCa) and left carotid (LCa), celiac (Ca) and renal artery (Ra) flows during extracorporeal circulation. Methods: A mock circulatory circuit was assembled, based on a compliant anatomical aortic model. The ascending aorta, right subclavian and femoral artery cannulations were created and flow was provided by a centrifugal pump (Cp); cardiac output was provided by a roller pump (Rp). Five volume flow rates were tested. The Rp was set at 4 L/min with no Cp flow (R4-C0) and the basic volume flow rates of the vessels were measured. The flow of the Cp was increased while the Rp flow was decreased for other measurements; R3-C1, R2-C2, R1-C3 and R0-C4. Measurements were repeated for all cannulation sites. Results: The RCa flow rate at R4-C0 was higher compared to the R3-C1, R2-C2, R1-C3 and R0-C4 RCa flows with subclavian cannulation. The RCa flow decreased as the Cp flow increased (p<0.05). The RCa flow with ascending aortic and femoral cannulation was higher compared to subclavian cannulation. Higher flows were obtained with subclavian cannulation in the LCa compared to the others (p<0.05). R4-C0 Ca and Ra flows were higher compared to other Ca and Ra flows with femoral cannulation. Ca and Ra flows decreased as Cp flow increased. Flows of the Ca and Ra with ascending and subclavian cannulations were not lower compared to the R4-C0 flow (p<0.05). Conclusion: This study shows that prolonged extracorporeal circulation may develop flow decrease and ischemia in cerebral and abdominal organs with both subclavian and femoral cannulations.

Body mass index as a determinant of postoperative morbidity

BACkGRouND: The impact of obesity on postoperative mortality and morbidity in coronary artery bypass grafting (CABG) operations is a widely studied but poorly defined topic. oBjECTIVE: To investigate the effect of body mass index (BMI) on inhospital mortality and morbidity after isolated CABG surgery. METhoDS: Prospectively collected data of a series of 1057 consecutive patients who underwent on-pump isolated CABG surgery were retrospectively analyzed. Patients were divided into five groups according to WHO BMI categorization (defined as underweight [BMI <20 kg/m2]; normal weight [BMI ≥20 kg/m2 to <25 kg/m2]; overweight [BMI ≥25 kg/m2 to <30 kg/m2]; obese [BMI ≥30 kg/m2 to <35 kg/m2]; and morbidly obese [BMI ≥35 kg/m2]). RESulTS: Of 1057 patients, 13 patients (1.2%) were underweight, 298 (28.2%) were normal weight, 462 (43.7%) were overweight, 218 (20.6%) were obese and 66 (6.2%) were morbidly obese. The mean age was significantly lower in underweight patients, who were also more likely to be male. In contrast, obese and morbidly obese patients were older, and more likely to have comorbidities such as diabetes and hypertension. The incidence of postoperative bronchodilator use (P<0.001), leg wound infection (P=0.038), sternal dehiscence (P=0.039) and development of new-onset atrial fibrillation (P<0.001) was significantly higher in obese and morbidly obese groups. In contrast, postoperative prolonged ventilation (P<0.001), need for blood transfusions (P<0.001) and revision for bleeding (P=0.041), as well as gastrointestinal complications (P<0.001), were significantly higher in underweight patients. Multivariate logistic regression analysis showed that female sex, older age and diabetes mellitis, but not BMI, were independent risk factors for early mortality after CABG surgery. CoNCluSIoN: No effect of BMI on early postoperative mortality after CABG surgery could be demonstrated. However, in terms of morbidity, postoperative bleeding and revision for bleeding were increased in underweight patients while sternal dehiscence, wound infections and occurrence of atrial fibrillation were increased in obese and morbidly obese patients.

An experimental model of aortic surgery and the effect of Iloprost on lung injury

Abstract Objectives. Ischemia/reperfusion (I/R) damage of the lung is a frequently encountered complication following aortic surgery. The aim of the present study is to investigate the histopathological effects of Iloprost on pulmonary damage developed after I/R. Design. Twenty-four Sprague-Dawley rats were randomly divided into 3 groups. In the control group, aortas were not clamped. In the I/R group, aortas were occluded, and after 1 h of ischemia, clamps were removed. After 2 h of reperfusion period, lungs of the rats were extracted. In the I/R + Iloprost group after 1 h of ischemia, Iloprost infusion was initiated, and maintained for the duration of 2 h reperfusion period. For histopathological scoring, density of polymorphonuclear leucocytes, congestion, interstitial edema, and bleeding were semiquantitatively evaluated, and histopathological changes were scored. Results. In the I/R group, multifocal-marked histopathological changes in 5 (62.5%), and multifocal-moderate histopathological changes in 3 (37.5%) rats were detected. In the I/R + Iloprost group, multifocal-moderate histopathological changes in 4 (50%), and multifocal-mild changes in 4 (50%) rats were detected. Conclusions. In the experimental rat model, administration of Iloprost has been shown to have preventive effects for pulmonary damage occurring after I/R generated by infrarenal aortic occlusion.

Effect of obesity on postoperative outcomes in patients with left ventricular assist device

We congratulate Volkovicher and colleagues for their successful study [1]. We found the main outcome of their study very interesting that obesity is not a risk factor for mortality in patients with left ventricular assist device (LVAD). Even as the authors have briefly stated in the discussion section, obesity does not seem to be a risk factor for mortality in similar studies with LVAD patients [2, 3]. However, this does not exactly coincide with our current knowledge of the general outcome of the cardiac surgery. Because obesity is described as a risk factor for mortality in many studies involving cardiac surgery without any LVAD patient [4–6]. In many of these studies, apart from mortality rate, the negative effects of obesity on many parameters such as re-hospitalization, the incidence of postoperative surgical infection, prolonged duration of stay in the intensive care unit, prolonged ventilation, and the incidence of postoperative renal failure have been reported. In the authors’ study, obesity does not seem to be a problem in terms of mortality and many of these parameters. But, the remarkable expression in these studies we have exemplified is “extreme obesity”. So, the main issue mentioned in these studies is extremely high body mass index (BMI). In fact, in the authors’ study, mortality rate is also seen to increase somewhat as the BMI increases. Is not there too much generalization in this context while reporting that obesity has no effect on mortality? Would not it be more appropriate to emphasize that the situation is different in obese patients with morbid obesity? We believe that learning about the authors’ ideas on this subject will add value to their study.

Regarding the Diabetic Patients Undergoing Off-Pump Coronary Bypass

1. Fukunaga N, Koyama T. Pay attention to mitral valve repair with autologous pericardial leaflet augmentation (letter). Ann Thorac Surg 2017;103:689. 2. Mihos CG, Pineda AM, Capoulade R, Santana O. A systematic review of mitral valve repair with autologous pericardial leaflet augmentation for rheumatic mitral regurgitation. Ann Thorac Surg 2016;102:1400–5. 3. Chauvaud S, Jebara V, Chachques JC, et al. Valve extensionwith glutaraldehyde-preserved autologous pericardium. Results in mitral valve repair. J Thorac Cardiovasc Surg 1991;102:171–7. 4. Baumgartner H, Hung J, Bermejo J, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr 2009;22:1–23.

The significance of aortic overriding and pulmonary stenosis in tetralogy of Fallot.

Congratulations to Dr Anderson and his colleagues for their work in the pathway of clarifying the disagreements in the definition and diagnosis of tetralogy of Fallot. The phenotypic feature of tetralogy of Fallot is malalignment of the outlet septum in combination with abnormal septo-parietal trabeculations such that there is subpulmonary muscular obstruction. When obstruction within the right ventricular outflow tract is minimal, it can be hard to distinguish tetralogy from the variant of ventricular septal defect with aortic overriding, known as the Eisenmenger defect. In addition, partially restrictive or nonrestrictive ventricular septal defects can be associated with moderate or severe infundibular pulmonary stenosis protecting the pulmonary vascular bed against increased blood flow, high pulmonary pressure, and the development of pulmonary vascular disease. In order to make the accurate diagnosis in tetralogy of Fallot and differentiate between tetralogy of Fallot and ventricular septal defect with pulmonary infundibular stenosis, echocardiography may not be adequate. Dynamic MRI and CT investigations would be more beneficial in order to reveal the anatomical details of the malformed heart. This issue is crucial because the definitive treatment of tetralogy of Fallot is surgery including the closure of the ventricular septal defect and transannular patch plasty, whereas pulmonary infundibular stenosis developing secondary to ventricular septal defect could regress after closure of the ventricular septal defect either by surgery or percutaneously. Percutaneous closure could be performed if there is no aortic overriding. If there is some degree of aortic overriding – doubly committed biventricular connection – the closure device may settle on aortic leaflets due to lack of the superior rim. In that case, the closure device may not be applied. If there are infundibular stenosis secondary to ventricular septal defect and overriding aorta, surgical ventricular septal defect closure may be performed earlier so that an additional pulmonary transannular patch plasty is avoided. If there is infundibular stenosis secondary to ventricular septal defect without overriding aorta – subaortic ventricular septal defect – early percutanous closure may be performed in order to prevent further progression of infundibular stenosis. In summary, detailed investigation of ventricular septal defect plus pulmonary stenosis should be carried out. Confirming the diagnosis as tetralogy of Fallot requires doublechecking the patient’s images and even adding the tomographic or magnetic resonance evaluation. This “sceptical” approach would prevent unnecessary pulmonary transannular patch plasty that itself may stick a life-long disorder to be followed-up.

Graft Materials for Popliteal Artery Patch Plasty.

for the medical community regarding cardiovascular prevention, a large percentage of patients with symptomatic PAD who present to the vascular surgery services do not receive appropriate therapy for their risk factors to meet the required targets. Thus, vascular surgeons may have an important role along these lines. In clinical practice, vascular surgeons should be able to validate and optimize insufficient medical treatment of risk factors when they see the patients for the first time and to monitor the achievement of the targets during the follow-up. Thus, vascular surgeons should be able to prescribe low dose of Acetylsalicylic Acid (ASA, 75e160 mg), which has been shown to be protective and probably safer in terms of gastrointestinal bleeding. Referral to other specialties should be considered immediately if needed, especially for antihypertensive drugs modification and DM treatment regulation. In respect to smoking cessation, there is concreteevidence from randomized controlled trials and meta-analysis that multidisciplinary approachwithpsychosocial support (counseling),psychosocial intervention (cognitivebehavioral therapy method), and pharmacotherapy can help patients quit smoking. Smoking should be considered and managed as a chronicdisease similarly toother risk factors, thus these factors will require for their management a long-termmultidisciplinary strategy, in which the vascular surgeon could play an auxiliary role during follow-up after conservative or even invasive treatment of PAD. Along with smoking, HL is also an equally important risk factor that very often is neglected by physicians in the management of patients with PAD. Statin therapy not only improves walking capacity but it also reduces cardiovascular morbidity and mortality. The target to achieve low-density lipoprotein cholesterol level is lower than 2.5 mmol/L (100 mg/dL) and could be attained following the established guidelines and always monitoring the patients for any adverse effect. As vascular surgeons are the physicians who mainly follow-up patients with PAD on a regular basis, they should play a leading role in the monitoring and maintenance of risk factor management to the required targets. It is important to highlight that guidelines have been developed with the co-operation of working groups in which Vascular Surgery Society is an equivalent and active member.