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.

Should we change the cannulation site for right subclavian artery cannulation? An experimental study with a newly designed cannula.

BACKGROUND:: In this experimental study, we primarily aimed to show the hemodynamic effects and superiority of this newly designed cannula for perfusion compared to standard subclavian cannulation. The new cannula (Figure 1) allows bidirectional axial flow and it directly fits in the brachiocephalic trunk (innominate artery). METHODS:: We used a cardiopulmonary bypass roller pump, reservoir, 3/8- 1/2- 1/4-inch Y-connectors and tubing set. Lines were set as seen in Figures 2, 3, 4 and 5. The anatomy of the aorta (ascending, arch, branches, descending) was mimicked, using tubing sets with different sizes and the connectors yielding similar angles and configurations. In this experimental vascular system, systemic vascular resistance was created with partial clamping of the common tubing set. The cannulation sites were created in the subclavian artery and the innominate artery. Perfusion was established with the same pump rate and the same occlusion pressures (systemic vascular resistance). The pressure readings were obtained in the right carotid artery, the left carotid artery and the left subclavian artery. RESULTS:: These experimental models of vasculature allowed us to measure pressures in the carotid system for different cannulation set-ups, using both our newly designed double-outflow cannula, which was introduced via the innominate artery, and the standard arterial cannula, which was introduced via the subclavian artery. Higher pressure recordings were obtained in the carotid system with the new cannula introduced through innominate artery. CONCLUSION:: Higher cerebral perfusion readings were obtained with our newly designed bidirectional cannula introduced via the innominate artery compared to standard cannulation through the right subclavian artery.

Coronary artery bypass surgery: beating heart or cardiopulmonary bypass?

In this study, we examined the early results for patients who underwent beating heart coronary bypass surgery and compared these results with those of conventional coronary bypass surgery.A total of 1094 patients who underwent isolated coronary artery bypass surgery between January 2009 and December 2011 in our clinic were included in this study. Seventy-three patients in whom cardiopulmonary bypass was not used (group 1) were compared to 1021 patients in whom cardiopulmonary bypass was used (group 2).The mean age was 60.7 ± 9.3 in group 1 and 58.9 ± 9.7 in group 2 (P > 0.05). There was no significant difference between the two groups in terms of gender, or the coexistence of diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), and hypertension (P > 0.05). There was no significant difference between group 1 and group 2 in terms of development of postoperative atrial fibrillation (AF), use of an intra-aortic balloon pump, need for re-operation for bleeding, or duration of hospital stay and intensive care unit stay (P > 0.05). The need for inotropic support and the amount of mediastinal drainage were less in group 1 than in group 2 (P = 0.002, P < 0.001). The incidences of postoperative cerebrovascular accident, development of chronic renal failure, and sternal wound infection did not significantly differ between the groups (P > 0.05). There was no mortality in group 1, whereas it was calculated as 1.8% in group 2 (P = 0.63).Beating heart coronary artery bypass surgery decreases the need for inotropic support and transfusion.

Inflammation, Atrial Fibrillation and Cardiac Surgery: Current Medical and Invasive Approaches for the Treatment of Atrial Fibrillation.

Atrial fibrillation (AF) is a cardiac dysrhythmia commonly seen in clinical practice especially after cardiac surgery. It is associated with increased morbidity and mortality for the patients. The pathogenesis of AF is not exactly understood yet, but there is growing data about the relationship between AF and inflammation. Cardiac surgery itself is a big source for inflammation. It causes major surgical trauma, ischemia/reperfusion injury, hypothermia, low arterial pressure, and the equipment of cardiopulmonary bypass makes a large foreign surface thus it activates inflammatory response. There is a large number of data about the treatment options of AF and there are also strategies, which are related to reduction of inflammatory activation during cardiopulmonary bypass. In order to review the relationship between cardiac surgery, inflammation, AF and treatment strategies in patients with AF, we conducted a search through Pubmed for articles in English using the keywords: "atrial fibrillation, cardiac surgery, inflammation, medical therapy, surgical therapy, ablation therapy" from January 2012 to present. We also searched separately for each alternative treatment modality on Pubmed. To identify further articles, we also looked into related citations in review articles and commentaries. We searched thoroughly the guidelines published by the European Society of Cardiology (2016), and the American Heart Association/ American College of Cardiology/ Heart Rhythm Surgery (2014). Many studies concluded that inflammation contributes in the occurrence of AF. Inflammatory markers, such as CRP, interleukins and complements have high sensitivity and specificity for prediction of AF whether the patient having cardiac surgery or not. Betablockers, diltiazem and amiodarone are the most commonly used drugs for rate control in AF following surgery. Although there are some new therapeutic approaches to reduce postoperative inflammatory activation, such as the use of vitamins, fatty acids, statins, or technical improvements to cardiopulmonary bypass unit like miniaturized bypass circuits, heparin coating of the circuits, leukocyte filters, or various surgical approaches like off-pump coronary bypass surgery, we still need more effective strategies to reduce both postoperative inflammation and postoperative AF risk after cardiac surgery. Today we use more advanced invasive and surgical treatment strategies for AF although we need far more advanced technics to reduce perioperative inflammatory activation, which actually causes AF.

The low levels of bone morphogenic protein-4 and its antagonist noggin in type 2 diabetes.

OBJECTIVE: Bone morphogenic protein-4 (BMP-4) is a proinflammatory cytokine which is controlled by BMP-4 antagonists. Our aim was to investigate the levels of BMP-4 and its antagonists, noggin and matrix Gla protein (MGP), in prediabetes and diabetes. DESIGN: One hundred and forty-two type 2 diabetic, 32 prediabetic, and 58 control subjects participated in this cross-sectional study. BMP-4, noggin, and MGP were measured with the ELISA method. RESULTS: There was a significant difference between the three groups in relation to sex, hypertension, fasting plasma glucose, HbA1c, lipid profiles, and diastolic blood pressure (p < 0.05). BMP-4 levels were significantly lower in the diabetic group compared to the control group (108.5 and 127.5 ng/mL, respectively, p < 0.001 diabetes vs. control). Noggin levels were significantly lower in the diabetic group compared to the prediabetic and control groups (10.5, 11.5, and 12.0 ng/mL, as median, respectively, p < 0.001; diabetes vs. control, p = 0.002; diabetes vs. prediabetes). BMP-4 was associated significantly with noggin in the entire study population (ß coefficient = 0.796, p < 0.001). Receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve was 0.708 (95% CI 0.551-0.864, p = 0.011) for BMP-4 levels. The optimal cutoff value of BMP-4 for detecting albuminuria was 118.5 ng/mL for which sensitivity was 71.4% and specificity was 66.4%. CONCLUSIONS: BMP-4 and noggin levels were lower in the diabetic group. High BMP-4 levels were significantly associated with albuminuria. Further studies are warranted to determine the role of BMP-4 in the pathogenic processes underlying albuminuria and hyperglycemia in patients with type 2 diabetes.