Adverse Effects Of Cardiopulmonary Bypass Research Articles

Modified cardiopulmonary bypass with low priming volume for blood conservation in cardiac valve replacement surgery

BackgroundThe adverse effects of cardiopulmonary bypass during open cardiac surgery, including hemodilution, seem to be inevitable, especially for patients who generally have a relatively lower BMI with relatively small blood volumes. This study reports the modification and use of a cardiopulmonary bypass (CPB) system to reduce priming volume and hemodilution.MethodsThis is a retrospective study of 462 adult patients who underwent cardiac valve replacement surgery from January 2019 to September 2021 at the General Hospital of Western Theater Command. The modified group consisted of 212 patients undergoing modified CPB. The control group included 250 patients receiving conventional CPB. Evaluated indices included fluid intake and output volumes during CPB, intraoperative indices related to CPB operation, usage of blood products during the peri-CPB period, and postoperative outcomes.ResultsThe modified group displayed a significant reduction in the crystalloid (200 mL vs. 600 mL, P < 0.05) and colloid priming volumes (450 mL vs. 1100 mL, P < 0.05), and ultrafiltration solution volume (750 mL vs. 1200 mL, P < 0.05). Furthermore, the modified group had a significantly lower rate of defibrillation (30.2% vs. 41.2%, P < 0.05). The intraoperative urine volume (650 mL vs. 500 mL, P < 0.05) and intraoperative hematocrit (Hct) (26% vs. 24%, P < 0.05) of the modified CPB group were also higher than in the control group. The modified group required a lower infusion volume of packed red blood cells (250 mL vs. 400 mL, P < 0.05) and lower infusion rates of packed red blood cells (17.9% vs. 25.2%, P < 0.05) and fresh frozen plasma (1.41% vs. 5.2%, P < 0.05). In addition, the modified group showed significantly improved indices related to postoperative recovery.ConclusionsThe modified CPB system effectively conserves blood and shows noteworthy potential for application in cardiac valve replacement surgery.

Importance of anastomotic sequencing during off-pump coronary artery bypass surgery: a pilot strategy

Introduction: Off-pump coronary artery surgery is a method preferred by many surgeons today to avoid the adverse effects of cardiopulmonary bypass. However, this method was quite popular at first but was later abandoned by some surgeons due to unfavorable results. We think the anastomosis sequence is an essential issue when performing off-pump surgery. We aimed to examine the effects of this strategy on the results of off-pump coronary artery surgery. Methods: We included 601 patients with isolated coronary artery disease who underwent off-pump coronary artery bypass surgery between January 2020 and 2022. The main goal was to ensure sufficient blood was going through the myocardia while anastomosis was performed on one of the coronary arteries. We tried to create a strategy about the sequence in which we should do the coronary anastomosis. Results: In 2 patients, conversion to on-pump surgery was required in elective conditions due to hemodynamic instability during the operation (0.33%). Only 4 patients required surgical revision because of bleeding (0.67%) in the early postoperative period. We recorded wound infections that could be solved with medical therapy and routine wound dressing in 5 patients (0.83%). Discussion and Conclusion: After applying this strategy, we experienced much more minor and acceptable conversion rates than those reported in the literature. We believe this strategy will benefit other researchers who have just started practicing off-pump surgery.

Current Readings on Outcomes After Off-Pump Coronary Artery Bypass Grafting

Off-pump coronary artery bypass grafting (CABG) gained popularity in the 1990s through early 2000s as surgeons sought to mitigate the purported adverse effects of cardiopulmonary bypass and reduce the risk of neurologic events from aortic manipulation. Since then, results of several large randomized controlled trials and meta-analyses have failed to demonstrate an advantage of off-pump CABG over traditional on-pump CABG and have even raised concerns about potential suboptimal outcomes. The modern debate about off- vs on-pump CABG centers around long-term outcomes, the role of surgeon experience, identification of specific patient populations for which off-pump CABG is most appropriate, and identification of novel techniques and technologies to improve long-term outcomes. We review the key findings of 5 contemporary papers that address these issues and provide a current perspective on the status of off-pump CABG.

Use of Conventional Ultrafiltration in Patients with Pulmonary Hypertensive Mitral Valve Disease Undergoing Valve Surgery

Adverse effects of cardiopulmonary bypass on blood and lungs are encountered more severelyin pulmonary hypertensive patients undergoing mitral valve surgery. Aim of this study is to identify the favorable effects of conventional ultrafiltration on postoperative pulmonary functions, hemodynamics, morbidity or mortality in pulmonary hypertensive patients undergoing mitral valve surgery. 40 patients with severe pulmonary hypertension who underwent mitral valve surgery were included in study. Patients were divided into two groups according to whether conventional ultrafiltration was applied or not. Demographic data, preoperative transthoracic echocardiography, respiratory functions, complete blood count, biochemical parameters, alterations in pulmonary functions, bleeding, use of inotropic agents and blood products, intubation time, mortality, morbidity, length of intensive care unit and hospital stay, were evaluated. Intubation time (7.97±2.77 vs. 10.12±2.95; p 0.05) and inotropic agents (14 vs. 18; p>0.05) were less than the control group. Increase of pulmonary compliance, cardiac index, oxygen index, decrease of alveolar-arterial oxygen pressure difference and ventilation index were significant in both groups. Hematocrit (28.07±3.18 vs. 26.96±2.51; p>0.05) and white blood cell (13.56±2.37 vs. 13.03±2.51; p>0.05) were higher in the study. No morbidity and mortality were presentin both groups. Conventional ultrafiltration decreased the intubation time, intensive care unit stay, hospital stay, bleeding, use of blood products and inotropic agents. Favorable effects were also detected on pulmonary compliance, cardiac index, oxygen index, alveolar-arterial oxygen pressure difference and ventilation index. Studies with larger patient population, application of conventional and modified ultrafiltration together may give significant results for pulmonary functions.

Blood glucose monitoring in pediatric patients on cardio-pulmonary bypass

Background: Meticulous blood glucose control during cardio-pulmonary bypass has received a lot of attention recently. Children are more vulnerable to adverse effects of cardio-pulmonary bypass (CPB) on glucose homeostasis. Objectives of the study were to find out changes in blood glucose due to cardio-pulmonary bypass and the Insulin requirements intra - operatively. Methods: A single centre, prospective trial in 130 children undergoing cardiac surgery for congenital cyanotic/ acyanotic heart disease, requiring cardio-pulmonary bypass. We administered dextrose IV 0.5g/kg/hr in pre bypass period to avoid hypoglycemia. Blood glucose levels were measured at various point of time [baseline, after 10 min and then every half hourly during bypass, 30 minutes after bypass and next during the immediate post-operative using a Hemo-cue glucometer]. To control blood glucose on cardio-pulmonary bypass pump, we used inj. Insulin as per study protocol. The statistical analysis was done using paired and unpaired t test & chi square test. Results: We had examined 130 pediatric patients going on CPB for cardiac surgery. Blood glucose was monitored in patients who did not required inj. Insulin (Group II) on bypass for hyperglycemia (n=33) while 97 patients required insulin (Group I) on bypass because of hyperglycemia. 74% of patient required insulin on pump shows that cardio-pulmonary bypass significantly affects glucose homeostasis in children; most of the children (43%) required insulin 30 min after starting cardio-pulmonary bypass. Conclusions: Blood glucose rise in children of congenital cardiac disease was significant after induction of anesthesia; on hypothermic CPB children of congenital cardiac disease may had rising blood glucose trend and the pre-operative blood glucose significantly affects the trend of blood glucose on CPB. The duration of CPB might not significantly affect insulin requirement of pediatric patients. CPB significantly affected glucose homeostasis in children. Hence it seems prudent to administer small amount of IV dextrose in prebypass period to avoid hypoglycemia but rate and dose of insulin should be adjusted as it may affect blood glucose level on CPB.

Effects of Mannitol and Dopamine on Renal Function in Coronary Artery Bypass Surgery

Effects of Mannitol and Dopamine on Renal Function in Coronary Artery Bypass SurgeryObjective: To compare the effects of dopamine and mannitol which are used to reduce the negative effects of long-term cardio-pulmonary bypass (CPB) on kidney function in according to manner of administration and by the time. Material and Methods: Group 1 (n = 25 patients): Mannitol (M) 1 g kg was added to a priming solution of CPB. Group 2 (n = 25 patients): Dopamine infusion (D) (2 mg kg min IV) was used from induction of anesthesia until end of the operation. Group 3 (n = 25 patients): D (2 mg kg min IV) was used from induction of anesthesia until end of the operation and M 1 g kg in the priming solution of CPB. Group 4 (n = 25 patients) (Control Group): Furosemide was performed in case of a decrease of urine. The values of serum urea, creatinine, albumin, urine microalbumin, urine creatinine, serum cystatin-C were compared to preop and postop periods.Results: Postop Cystatin C levels in Group I, II, III were observed a significant rise. The levels of Microalbumin / creatinine ratio in urine in all the groups at postop were seen advanced statistical significant (p <0.01). Conclusion: To determine kidney damage we have observed that microalbumin / creatinine ratio in urine compared to the Cystatin C level is to be a more sensitive parameter. We think that the use of D (2 µg kgmin ) combined with M (1 g kg) added during CPB is more effective in terms of preventing adverse effects of CPB on renal function.

Cardiac surgery and anesthesia approach in an elderly patient population

Due to the increase in the average life expectancy and the higher incidence of cardiovascular disease with advancing age, an increasing number of elderly patients undergo cardiac surgery today. However, advanced age is associated with decreased physiologic reserve capacity and significant comorbidities including diabetes mellitus, renal dysfunction, cerebrovascular disease and chronic lung disease. These factors and effects of systemic inflammatory response associated with cardiopulmonary bypass (CPB) on organs and systems have a greater impact on morbidity and mortality in older patients than the younger ones. As a result, for elderly patients with additional multi-systemic risks, cardiac surgery is a real trauma with its own multisystemic effects. It requires a specific and careful approach in terms of surgery and anesthesia. The adverse effects of CPB on the organ systems which are traumatized by aging and associated illnesses should be well-established and examined together. Novel pharmacological agents, surgical techniques, improved technology and perfect anesthesiology preparation, management and complete monitoring are of utmost importance for the success of cardiac surgery in elderly.

Are minimized perfusion circuits the better heart lung machines? Final results of a prospective randomized multicentre study

Minimized perfusion circuits (MPCs), although aiming at minimizing the adverse effects of cardiopulmonary bypass, have not yet gained popularity. This can be attributed to concerns regarding their safety, as well as lack of sufficient evidence of their benefit. Described is a randomized, multicentre study comparing the MPC - ROCsafeRX to standard cardiopulmonary bypass in patients undergoing elective coronary artery bypass grafting and/ or aortic valve replacement. Five hundred patients were included in the study (252 randomized to the ROCsafeRX group and 248 to standard cardiopulmonary bypass). Both groups were well matched for demographic characteristics and type of surgery. No operative mortality and no device-related complications were encountered. Transfusion requirement (333 ± 603 vs. 587 ± 1010 ml; p=0.001), incidence of atrial fibrillation (16.3% vs. 24.2%; p=0.03) and the incidence of major adverse events (9.1% vs. 16.5%; p=0.02) were all in favour of the MPC group. These results confirm both the safety and efficacy of the ROCsafeRX MPC for a large variety of cardiac patients. Minimized perfusion circuits should, therefore, play a greater role in daily practice so that as many patients as possible can benefit from their advantages.

New technique of off-pump atrial septostomy for complex congenital cardiac anomalies

Atrial septostomy is essential for palliation of some complex congenital cardiac anomalies, such as transposition of the great arteries and left-/right-sided atrioventricular valve stenosis or atresia. Conventionally, balloon atrial septostomy is done in neonates. Beyond the neonatal period, surgical septostomy is done using cardiopulmonary bypass and can lead to increased morbidity and mortality. We report a new technique of atrial septostomy without cardiopulmonary bypass and its follow-up. Eleven cases underwent atrial septostomy without using cardiopulmonary bypass from January 2009 to June 2010. Median age of patients was 7 months (2-12 months) and median weight was 6.3 kg (range 4.5-10 kg). Surgical septostomy was performed through the right atrial appendage with a Tubb's dilator, aided by intra-operative transesophageal echocardiography. Atrial septal defect (ASD) less than 5mm was enlarged with a Kerrison bone punch and then dilated with a Tubb's dilator. Associate procedures performed were off-pump Glenn in seven cases, pulmonary artery (PA) banding in three cases, and shunt with PA band in one case. All the restricted ASDs were successfully enlarged with adequate interatrial shunting without any gradient. Echocardiography revealed no evidence of introduction of air or particulate emboli, and no tricuspid valve injury or heart block. There was no postoperative mortality. Follow-up ranged from 1 to 18 months (median 11 months). Echocardiography showed good PA band gradient/well-functioning Glenn shunt and unobstructed ASD with good oxygen saturation. This technique demonstrates the surgical feasibility of a beating-heart atrial septostomy. It avoids the adverse effects of cardiopulmonary bypass, reduces morbidity, and has no mortality. It is safe, economical, and easily reproducible. To our knowledge, this technique has not been reported in literature so far.

Effect of Cardiopulmonary Bypass on Cancer Prognosis

Adverse effects of cardiopulmonary bypass on cancer prognosis are expected but have not been confirmed. Seventy-four cancer patients who underwent cardiac surgery before cancer therapy were followed up for 42 ± 37 months; 45 had cardiac surgery with cardiopulmonary bypass. There was no significant difference in cancer recurrence (40.0%) and deaths (26.7%) among patients who had cardiopulmonary bypass and those who underwent off-pump cardiac surgery (27.6% and 24.1%). There were no significant differences in freedom from cancer-related death at 2 and 5 years after cardiac surgery (78.4% and 68.5%) in the cardiopulmonary bypass group compared to the 29 off-pump group (81.8% and 58.3%). Despite some limitations, this study detected no significant adverse effects of cardiopulmonary bypass on cancer prognosis. Although these results do not verify the safety of cardiopulmonary bypass from an oncologic aspect, they suggest it can be applied in cancer patients who require cardiac surgery.

Influence of carotid artery stenosis on stroke in patients undergoing off-pump coronary artery bypass grafting

It is well known that the presence of carotid artery stenosis increases the risk of perioperative stroke in patients undergoing cardiac surgery with cardiopulmonary bypass. Although off-pump coronary artery bypass grafting (CABG) can avoid the adverse effects of cardiopulmonary bypass, the influence of carotid artery stenosis on the incidence of stroke in patients undergoing off-pump CABG has not been well clarified. We conducted a retrospective study of 461 patients who underwent elective off-pump CABG after screening for carotid artery stenosis at our institute between September 2004 and May 2007. The incidence and etiologies of stroke were identified. Preoperative screening revealed significant carotid artery stenosis in 49 patients. Clinical results were compared between patients with and without carotid artery stenosis. Postoperative stroke occurred in two (0.43%) of the 462 study patients, and in-hospital mortality occurred in three (0.65%). Stroke was due to decreased perfusion resulting from hypovolemic shock in one and thrombosis in the other. There was neither stroke nor in-hospital mortality in patients with carotid artery stenosis, although there were two strokes (0.49%) and three in-hospital mortalities (0.73%) in patients without carotid artery stenosis. The influence of carotid artery stenosis on the incidence of perioperative stroke may be little in off-pump CABG, especially in patients with moderate carotid artery stenosis.

A randomized, controlled trial of aprotinin in neonates undergoing open‐heart surgery

Neonates undergoing open-heart surgery are especially at risk for massive bleeding and pronounced inflammation. The efficacy of aprotinin, a serine protease inhibitor, at ameliorating these adverse effects of cardiopulmonary bypass has not been clearly demonstrated in neonates. Term neonates were enrolled and randomly assigned in a blinded fashion to receive saline (group P, placebo) or high-dose aprotinin (group A). Intraoperative management was standardized: surgeon, anesthesia, cardiopulmonary bypass and hemostasis therapy. Patients were admitted postoperatively to a pediatric cardiac intensive care unit. Primary outcome measure of efficacy was duration of the postoperative mechanical ventilation. Secondary outcome measures were total volume and units of blood products transfused intraoperatively and for 24 h after surgery, duration of chest tube in situ, and intensive care and hospital stays after surgery. Twenty-six neonates were enrolled; 13 received aprotinin and 13 received placebo. The study was halted prematurely because of US Food and Drug Administration's concerns about aprotinin's safety. Baseline patient, surgery and cardiopulmonary bypass characteristics were similar between groups. No outcome variables differed between groups (P > 0.05). Duration of postoperative ventilation was 115 +/- 139 h (group A); 126 +/- 82 h (group P); P = 0.29, and total blood product exposure was 8.2 +/- 2.6 U (group A); 8.8 +/- 1.4 U (group P); P = 0.1. Postoperative blood creatinine values did not differ between groups. In-hospital mortality rate was 4%. Aprotinin was not shown to be efficacious in neonates undergoing open-heart surgery. It is unclear whether adult aprotinin safety data are relevant to neonates undergoing open-heart surgery.

Comparison of Sleep and Mood in Patients After On-Pump and Off-Pump Coronary Artery Bypass Surgery

Off-pump coronary artery bypass surgical procedures have been advocated to reduce the adverse effects of cardiopulmonary bypass on the brain. To examine differences in objective and subjective characteristics of sleep and mood disturbance between patients after on-pump and off-pump coronary artery bypass surgery. In a secondary analysis of pooled data from 2 previous studies, sleep characteristics and mood disturbance on postoperative night 2 after transfer to the cardiac surgery step-down unit were compared in patients who had on-pump and off-pump cardiac surgery. The sample included 129 coronary artery bypass patients: 48 on-pump patients from one hospital and 81 off-pump patients from another hospital. Data were obtained with wrist actigraphs. Subjective characteristics of sleep were determined by using the Pittsburgh Sleep Quality Index and a sleep diary; mood disturbance was evaluated by using the short form of the Profile of Mood States. Off-pump surgery was associated with better objective sleep continuity (decreased percentage of wake time after sleep onset and fewer awakenings) but not longer sleep duration after controlling for age and sex. The 2 groups of patients did not differ overall in subjective sleep characteristics, mood disturbance, or preoperative sleep quality. Use of off-pump coronary artery bypass surgery may improve sleep continuity during the early postoperative period. Prospective longitudinal studies are needed to evaluate the potential long-term benefits of this procedure during the different phases of recovery.

Metabolic changes and clinical outcomes in patients undergoing on and off pump coronary artery bypass surgery

ObjectiveThough the advent of cardiopulmonary bypass saw a dramatic increase in the number of coronary bypass surgeries performed annually, a few surgeons continued to use off pump technique mainly for economic reasons. But the adverse effects of cardiopulmonary bypass necessitated a relook at the off pump technique. The study aims to assess the metabolic changes and clinical outcomes in patients undergoing on or off pump coronary bypass surgery.MethodsOne hundred patients with severe left ventricular dysfunction undergoing coronary bypass surgery on or off pump, fifty in each group, were studied for the metabolic changes and clinical outcomes. The results were statistically analysed using student’s t test.ResultsThe off pump group showed better postoperative renal function, and less incidence of lactic acidosis and oxidative stress than the cardiopulmonary bypass group. The former also had lesser need for ventilator support, shorter intensive care and hospital stay.ConclusionsThe off pump technique is associated with reduced myocardial injury, inflammatory response, and postoperative morbidity.

Off-pump coronary artery bypass surgery: anaesthetic implications and the Trinidad experience

To review the evolution of off-pump coronary artery bypass surgery with particular reference to the anaesthetic and perioperative implications. After review of the literature regarding coronary artery bypass grafting, the adverse effects of cardiopulmonary bypass on the various systems are discussed The development and the present status of off-pump coronary artery bypass surgery and its anaesthetic implications are reviewed These are discussed under the categories of preoperative, intra-operative and postoperative concerns. In Trinidad and Tobago, various cardiac surgical teams from different parts of the world conduct cardiac surgery. The cardiac anaesthesia team therefore has the unique opportunity of working with several teams who employ different techniques. Off-pump coronary artery bypass grafting surgery has distinct anaesthetic implications. In Trinidad and Tobago, the majority (85%) of the coronary revascularization surgeries are being done by this technique. Because of the lower cost and improved outcomes, this technique could be recommended to other developing countries of the region.

A Failure Mode Effect Analysis on Extracorporeal Circuits for Cardiopulmonary Bypass

Although many refinements in perfusion methodology and devices have been made, extracorporeal circulation remains a contributor to neurological complications, bleeding coagulopathies, use of blood products, as well as systemic inflammatory response. With the exposure of these adverse effects of cardiopulmonary bypass, the necessity to re-examine the safety of extracorporeal circuits is vital. A failure mode effect analysis (FMEA) is a proven proactive technique developed to evaluate system effect or equipment failure. FMEA was used to evaluate the six different types of extracorporeal circuits based on feedback from five clinical experts. Cardiovascular device manufacturers, the Veteran’s Administration National Center for Patient Safety, and the Joint Commission on Accreditation of Healthcare Organizations recommend the use of FMEA to assess and manage risks in current and developing technologies and therapies. This analysis investigates the safety of six types of extracorporeal circuits used in coronary revascularization, including the newer miniaturized extracorporeal circuits. The FMEA lists and ranks the hazards associated with the use of each cardiopulmonary bypass extracorporeal circuit type. To increase the safety of extracorporeal circuits and minimize the effects associated with cardiopulmonary bypass, perfusionists must incorporate FMEA into their clinical practice.

Bidirectional Glenn procedure without cardiopulmonary bypass

Background Whether the bidirectional Glenn procedure is better performed without the support of cardiopulmonary bypass is still a matter for debate. In this paper we discuss the indications and methods for bidirectional Glenn shunt without cardiopulmonary bypass. Methods Twenty patients with complex cyanotic congenital heart defects underwent a bidirectional Glenn shunt without cardiopulmonary bypass between May 2000 and August 2002. There were 10 male and 10 female patients, the mean age was 2.7 ± 2.6 years (range, 3 months to 11 years), and the mean weight was 11.0 ± 6.0 kg (range, 4.5 to 32 kg). The mean transcutaneous oxygen saturation was 74.3% ± 5.7% before the operation. The Glenn shunt was performed under venoatrial or venopulmonary shunt. Results All patients survived. Mean superior vena cava clamping time was 24.3 ± 4.7 minutes, and mean vena cava pressure was 26.9 ± 5.5 mm Hg during clamping. There were no postoperative neurologic complications. Follow-up echocardiography showed functioning Glenn shunts without any obstruction at the anastomosis. Conclusions The adverse effects of cardiopulmonary bypass could be eliminated by this method. This is an advantage during the postoperative recovery, but patients should be strictly chosen.

Invited commentary

Hemodynamic instability occurs frequently during off-pump coronary artery bypass (OPCAB) as a result of manipulation of the beating heart. This is particularly the case when the heart has to be lifted and rotated during coronary surgery in order to expose the coronary vessels of the lateral and inferior wall. Under these circumstances, diastolic filling of the right ventricle is compromised, leading to a reduced blood flow to the pulmonary artery. This reduces the filling of the leftventricle, which decreases stroke volume and cardiac output. A right ventricular assist device (RVAD) used during OPCAB pumps blood to the pulmonary circulation to maintain cardiac output and stabilize systemic hemodynamics.Based on this rationale, Caputo and colleagues evaluated such a RVAD, the A-Med system, in a randomized study in OPCAB patients. A major finding of this study is a significant reduction of central venous pressure in the RVAD-supported patients during exposure of coronary vessels located on the lateral and posterior ventricular wall. This beneficial effect may have contributed to maximal left ventricular filling and maintenance of hemodynamic stability, which, regrettably, is not detailed in this report. The findings of a reduced inflammatory response in OPCAB patients compared with on-pump patients are in line with previous publications.It seems clear that patients who are operated off-pump (ie, by eliminating the adverse effects of cardiopulmonary bypass on blood elements and humoral components) develop a far lesser postoperative inflammatory response than patients that are operated on-pump. However, surgical trauma and other operative events still cause a mild to moderate inflammatory response in OPCAB patients, as seen in this report by a transient postoperative elevation of Interleukine-6, Interleukin-8, complement C3a, and markers of organ injury Troponin I and S100. According to this study, there seems to be no difference between the OPCAB and RVAD patients regarding their postoperative inflammatory response and organ function, which suggests that the use of this RVAD does not promote inflammation indicated by comparable inflammation as in OPCAB patients without RVAD.As OPCAB operations are now more widely applied in coronary surgery, it is important to investigate which category of patients, especially those with high-risk profiles who benefit most from RVAD support. Hemodynamic instability occurs frequently during off-pump coronary artery bypass (OPCAB) as a result of manipulation of the beating heart. This is particularly the case when the heart has to be lifted and rotated during coronary surgery in order to expose the coronary vessels of the lateral and inferior wall. Under these circumstances, diastolic filling of the right ventricle is compromised, leading to a reduced blood flow to the pulmonary artery. This reduces the filling of the leftventricle, which decreases stroke volume and cardiac output. A right ventricular assist device (RVAD) used during OPCAB pumps blood to the pulmonary circulation to maintain cardiac output and stabilize systemic hemodynamics. Based on this rationale, Caputo and colleagues evaluated such a RVAD, the A-Med system, in a randomized study in OPCAB patients. A major finding of this study is a significant reduction of central venous pressure in the RVAD-supported patients during exposure of coronary vessels located on the lateral and posterior ventricular wall. This beneficial effect may have contributed to maximal left ventricular filling and maintenance of hemodynamic stability, which, regrettably, is not detailed in this report. The findings of a reduced inflammatory response in OPCAB patients compared with on-pump patients are in line with previous publications. It seems clear that patients who are operated off-pump (ie, by eliminating the adverse effects of cardiopulmonary bypass on blood elements and humoral components) develop a far lesser postoperative inflammatory response than patients that are operated on-pump. However, surgical trauma and other operative events still cause a mild to moderate inflammatory response in OPCAB patients, as seen in this report by a transient postoperative elevation of Interleukine-6, Interleukin-8, complement C3a, and markers of organ injury Troponin I and S100. According to this study, there seems to be no difference between the OPCAB and RVAD patients regarding their postoperative inflammatory response and organ function, which suggests that the use of this RVAD does not promote inflammation indicated by comparable inflammation as in OPCAB patients without RVAD. As OPCAB operations are now more widely applied in coronary surgery, it is important to investigate which category of patients, especially those with high-risk profiles who benefit most from RVAD support.

The systemic factor: the comparative roles of cardiopulmonary bypass and off-pump surgery in the genesis of patient injury during and following cardiac surgery

There is compelling evidence that off-pump coronary artery bypass operations are associated with reduced circulating levels of inflammatory mediators. Whereas complement activation and release of acute-phase reactants such as interleukin-6 are still expected to occur as consequences of a nonbypass-related general surgical trauma, a major feature of off-pump surgery seems to be a decreased production of interleukin-8, which may have important practical implications because of the participation of this cytokine in neutrophil trafficking and myocardial injury. The scarcity of carefully controlled, randomized trials precludes firm conclusions regarding the extent to which these biological changes translate into meaningful improvements in clinical outcomes. The problem is further complicated by the fact that the adverse effects of cardiopulmonary bypass largely depend on a genetically controlled balance between proinflammatory and antiinflammatory mediators. Currently, it is still impossible to predict, in a given patient, the side toward which this balance will be shifted. Nevertheless, accumulating experience identifies patient subgroups who may greatly benefit from avoiding extracorporeal circulation. These subsets include patients with severe extracardiac comorbidities (in particular, renal failure) and, possibly, patients with advanced left ventricular dysfunction, who may poorly tolerate superimposed, bypass-related, inflammatory tissue injuries.

Coronary artery stabilization causes endothelial damage: an electron microscopic study on dogs

In recent years, to protect patients from adverse effects of cardiopulmonary bypass, off-pump coronary artery bypass operations are performed. In these operations, effective coronary artery immobilization is the standard for a fine anastomosis. This is usually maintained with the help of prolene immobilization sutures, bulldog occluders or mechanical epicardial devices. The aim of this study is to show whether these stabilization devices cause any damage to the coronary artery endothelium. Sixteen dogs are included in this study and are divided into four groups. The control group consisted of one dog (Group I) and different immobilization techniques are applied to the other groups, which were five dogs each (Groups II, III, and IV). Coronary artery biopsies are obtained, then the samples are studied under scanning electron microscope (SEM) for endothelial injury and all samples are scored. Among the techniques used, bulldog occluders caused less injury on the coronary endothelium than the prolene sutures.