Myocardial protection during cardiac operations

Comparison of a coronary bypass surgery using a combination of both on-pump beating heart and cardioplegic arrest with conventional coronary bypass surgery using cardioplegic arrest on-pump

Objective

Antegrade cardioplegia may cause maldistribution in patients with multivessel coronary artery disease. Surgically bypassing large epicardial vessels before the cross-clamp and then administering cardioplegia from both the aortic root and the anastomosed grafts significantly prevent maldistribution and provide better cardiac protection.

Methods

This study included 80 patients, all older than 70 years with an ejection fraction between 25 and 35%. Patients were equally divided into two groups. Distal anastomoses to some of large epicardial coronary arteries were performed before the cross-clamp was placed. Grafted veins were attached to multi-perfusion set ports. Then, cross-clamping was performed, and the multi-perfusion set was disconnected from the aortic cannula and attached to the cardioplegia route. Antegrade cardioplegia was administered to both the aortic root and saphenous vein grafts. After all distal anastomoses were completed, the cross-clamp was removed, and the multi-perfusion set was connected to the aortic cannula again. Conventional coronary bypass techniques were used in group 2 patients.

Results

Inotropic agents were administered in 12 patients in group 1 and 29 patients in group 2 (p < 0.001). The average troponin I value in coronary sinus blood was 1.05 ± 0.8 ng/mL in group 1 and 3.12 ± 0.7 ng/mL in group 2 (p < 0.001). The average lactate value in coronary sinus blood was 1.15 ± 0.55 mmol/L in group 1 and 3.7 ± 2.4 mmol/L in group 2 (p < 0.001). Six patients died in the early postoperative period in group 2 (p = 0.028).

Conclusion

The current technique considerably reduces cross-clamping time and allows better distribution of the cardioplegic solution, preserving myocardium. Reduced coronary sinus lactate and troponin I levels also indicate better myocardial protection.

Blood versus crystalloid cardioplegia during triple valve surgery: A single center experience

BACKGROUND

The efficacy of different cardioplegia solutions on outcomes of complex cardiac operations such as triple valve surgery (TVS) is scarce. Here we compared the outcomes in TVS patients receiving either crystalloid (Bretschneider) or blood (Calafiore) cardioplegia.

METHODS

Screening of our institutional database with prospectively entered data identified 471 consecutive patients (mean age 70.3 ± 9.2 years; 50.9% male), who underwent TVS (replacement or repair of aortic, mitral and tricuspid valve) between December 1994 and January 2013. In 277 patients, cardiac arrest was induced with HTK-Bretschneider solution (HTK, n = 277, 58.8%), whereas 194 received cold blood cardioplegia (BCP) according to Calafiore (n = 194, 41.2%). Comparisons of perioperative and follow up outcomes were made between cardioplegia groups.

RESULTS

Preoperative patient characteristics and comorbidities were equally balanced between groups. 30-days mortality was similar between groups (HTK: 16.2%; BCP: 18.2%; p = 0.619). Incidence of the cumulative endpoint (30days mortality, myocardial infarction (MI), arrhythmia, low cardiac output syndrome or need for permanent pacemaker implantation) was also comparable (HTK: 47.6%; BCP: 54.8%, p = 0.149). In patients with reduced left ventricular ejection fraction (LVEF <40%), 30days mortality was higher in the HTK group (HTK 18/71 22.5%; BCP 5/50 10%; p = 0.037). Five-year survival was similar between groups (52 ± 6% for HTK and 55 ± 5% for BCP patients). In-Hospital mortality was best predicted by length of surgery and reperfusion ratio. Decreased age, shorter bypass time, preserved LVEF and concomitant surgical procedures have been found to be protective from long-term mortality.

CONCLUSIONS

Myocardial protection with HTK shows equivalent outcomes compared to BCP during TVS. Patients with reduced left ventricular function may benefit from BCP during TVS.

Controlling Reperfusion Injury With Controlled Reperfusion: Historical Perspectives and New Paradigms

Cardiac reperfusion injury is a well-established outcome following treatment of acute myocardial infarction and other types of ischemic heart conditions. Numerous cardioprotection protocols and therapies have been pursued with success in pre-clinical models. Unfortunately, there has been lack of successful large-scale clinical translation, perhaps in part due to the multiple pathways that reperfusion can contribute to cell death. The search continues for new cardioprotection protocols based on what has been learned from past results. One class of cardioprotection protocols that remain under active investigation is that of controlled reperfusion. This class consists of those approaches that modify, in a controlled manner, the content of the reperfusate or the mechanical properties of the reperfusate (e.g., pressure and flow). This review article first provides a basic overview of the primary pathways to cell death that have the potential to be addressed by various forms of controlled reperfusion, including no-reflow phenomenon, ion imbalances (particularly calcium overload), and oxidative stress. Descriptions of various controlled reperfusion approaches are described, along with summaries of both mechanistic and outcome-oriented studies at the pre-clinical and clinical phases. This review will constrain itself to approaches that modify endogenously-occurring blood components. These approaches include ischemic postconditioning, gentle reperfusion, controlled hypoxic reperfusion, controlled hyperoxic reperfusion, controlled acidotic reperfusion, and controlled ionic reperfusion. This review concludes with a discussion of the limitations of past approaches and how they point to potential directions of investigation for the future.

Myocardial protection: a forgotten modality

The goals of a cardiac surgical procedure are both technical excellence and complete protection of cardiac function. Cardioplegia is used almost universally to protect the heart and provide a quiet bloodless field for surgical accuracy. Yet, despite the importance of myocardial protection in cardiac surgery, manuscripts or dedicated sessions at major meetings on this subject have become relatively rare, as though contemporary techniques now make them unnecessary. Nevertheless, septal dysfunction and haemodynamic support (inotropes, intra-aortic balloon pump, assist devices) are common in postoperative patients, indicating that myocardial damage following cardiac surgery is still prevalent with current cardioplegic techniques and solutions. This article first describes why cardiac enzymes and septal function are the ideal markers for determining the adequacy of myocardial protection. It also describes the underappreciated consequences of postoperative cardiac enzyme release or septal dysfunction (which currently occurs in 40-80% of patients) from inadequate protection, and how they directly correlate with early and especially late mortality. Finally, it reviews the various myocardial protection techniques available to provide a detailed understanding of the cardioplegic methods that can be utilized to protect the heart. This will allow surgeons to critically assess their current method of protection and, if needed, make necessary changes to provide their patients with optimal protection.

How to Protect Hypertrophied Myocardium? A Prospective Clinical Trial of three Preservation Techniques

Protection of the hypertrophied myocardium during heart surgery is still a controversial matter. We prospectively studied 3 currently available preservation techniques in 60 patients operated on for isolated aortic stenosis. Patients were randomly assigned to one of the following groups:

CWB: continuous warm blood cardioplegia

ICB: intermittent cold blood with warm blood controlled reperfusion

Cryst: intermittent cold crystalloid cardioplegia (SLF11, Biosédra Laboratory, Vernon, France).

All groups were matched for age, ejection fraction, NYHA class, aortic valve surface, and operative risk score. There were no deaths. No statistically significant difference was found among the groups in terms of ventilatory support time, ICU stay time, hospitalization or atrial fibrillation occurrence. Blood gases in the coronary sinus at the time of clamp release showed deep acidosis with crystalloid cardioplegia (pH = 7.11 vs 7.39 for CWB and 7.38 for UCB, p < 0.0001) associated with a higher lactate production than in the other groups (1.3 mmol vs 0.5 for CWB and 0.58 for ICB, p < 0.0001). Acidosis was corrected at the end of bypass with no significant differences among groups. CK-MB samples were taken on arrival in ICU, then 6 and 24 hours later. These samples showed much higher levels with cold blood (H6: 70 mcg/l vs 33 for CWB and 45 for Cryst, p = 0.0019). Although the 3 types of cardioplegia may be safely used for isolated aortic stenosis surgery, continuous warm blood cardioplegia appears to be the best choice.

Post hoc analysis of the glutamics-trial: intravenous glutamate infusion and use of inotropic drugs after cabg

BACKGROUND

Intravenous glutamate reduced the risk of developing severe circulatory failure after isolated coronary artery bypass graft surgery (CABG) for acute coronary syndrome (ACS) in a double-blind randomised clinical trial (GLUTAMICS-ClinicalTrials.gov Identifier: NCT00489827 ). Here our aim was to study if glutamate was associated with reduced the use of inotropes.

METHODS

Post-hoc analysis of 824 patients undergoing isolated CABG for ACS in the GLUTAMICS-trial. ICU-records were retrospectively scrutinised including hourly registration of inotropic drug infusion, dosage and total duration during the operation and postoperatively.

RESULTS

ICU-records were found for 171 out of 177 patients who received inotropes perioperatively. Only one fourth of the patients treated with inotropes fulfilled study criteria for postoperative heart failure at weaning from cardiopulmonary bypass (CPB) or later in the ICU. Inotropes were mainly given preemptively to facilitate weaning from CPB or to treat postoperative circulatory instability (bleeding, hypovolaemia). Except for a significantly lower use of epinephrine there were only trends towards lower need of other inotropes overall in the glutamate group. In patients treated with inotropes (glutamate n = 17; placebo n = 13) who fulfilled study criteria for left ventricular failure at weaning from CPB the average duration of inotropic treatment (34 ± 20 v 80 ± 77 h; p = 0.014) and the number of inotropes used (1.35 ± 0.6 v 1.85 ± 0.7; p = 0.047) were lower in the glutamate group.

CONCLUSIONS

Intravenous glutamate was associated with a minor influence on inotrope use overall in patients undergoing CABG for ACS whereas a considerable and significant reduction was observed in patients with heart failure at weaning from CPB.

Preoperative levosimendan in ischemic mitral valve repair

Background

Levosimendan is a new calcium sensitizing drug with vasodilatory and inotropic properties, which is used for the treatment of postoperative low cardiac output syndrome and difficult weaning from cardiopulmonary bypass.

Objective

To evaluate the hemodynamic effects of levosimendan during and after coronary artery bypass grafting on cardiopulmonary bypass and mitral valve repair in patients with low left ventricular ejection fractions (<30%).

Methods

40 patients were enrolled in this double-blind prospective randomized controlled trial. They received either levosimendan or a placebo preoperatively ( n = 20) for 24 h. Clinical parameters were measured before and after administration. Any adverse events during and after drug administration and postoperative complications were evaluated.

Results

Patients treated with levosimendan exhibited a higher cardiac index and mean arterial pressure intraoperative and in the early postoperative period, compared to the control group. Patients treated with levosimendan required less ventilatory support ( p < 0.0001) and had shorter intensive care unit ( p < 0.0001) and hospital stay ( p < 0.0001).

Conclusions

Preoperative treatment with levosimendan in patients undergoing coronary artery bypass grafting and mitral valve repair resulted in improved hemodynamics and a stable postoperative course.

Integrated Cerebral Protection Combined Antegrade and Retrograde Cerebral Perfusion during Deep Hypothermic Circulatory Arrest

Objective

Aortic arch surgery requires temporary interruption of cerebral perfusion. Hypothermic circulatory arrest (HCA) is an established method of central nervous system protection for limited periods of absent cerebral blood flow. Adjuncts to increase the safe duration of circulatory arrest include either retrograde cerebral perfusion (RCP) or antegrade cerebral perfusion (ACP), with most complex aortic operations now performed using HCA with ACP. We reasoned that optimal cerebral protection might be achieved with a combination of ACP and RCP (integrated brain protection) and present an early clinical experience that supports this approach.

Methods

The integrated brain protection strategy included sequential overlapping periods of RCP, ACP, and RCP during HCA. Moderate systemic hypothermia (25°C) was used. Patient data were gathered through retrospective chart review.

Results

Between 2008 and 2009, six consecutive patients underwent ascending aortic graft replacement for acute type A dissection using HCA and integrated brain protection. The mean minimum systemic temperature was 22.9 ± 1.8°C, the mean total HCA time was 34 ± 5 minutes, and the mean duration of ACP and RCP was 22 ± 6 and 7 ± 5 minutes, respectively. Patients were awake and followed commands 10.1 ± 3.4 (range, 5–13) hours after operation, and there was no evidence of temporary neurologic dysfunction. There was no operative mortality.

Conclusions

Integrated brain protection using both RCP and ACP during HCA is a promising approach for the safe performance of complex aortic surgery and is worthy of evaluation in larger clinical series.

The S-100B substudy of the GLUTAMICS trial: glutamate infusion not associated with sustained elevation of plasma S-100B after coronary surgery

BACKGROUND & AIMS

Concerns have been raised about potential neurological injury related to exogenous glutamate. In cardiac surgery glutamate has been administered as a putative cardioprotective agent by cardioplegia or intravenous infusion. In the GLUTAMICS trial, in addition to surveillance of clinical neurological injuries, a prespecified subgroup was analyzed with regard to postoperative S-100B levels to detect potential subclinical neurological injury related to glutamate infusion.

METHODS

Sixty-nine patients operated on for unstable coronary syndrome were randomized to intravenous infusion of glutamate (n=35) or saline (n=34) perioperatively. Plasma levels of S-100B were obtained on the third postoperative day.

RESULTS

S-100B in the glutamate group and the control group were 0.079+/-0.034microg/L and 0.090+/-0.042microg/L respectively (p=0.245). There were no patients with stroke or mortality. Three patients in the control group and two in the glutamate group had postoperative confusion. These patients had significantly elevated S-100B compared with those without confusion (0.132+/-0.047vs 0.081+/-0.036microg/L; p=0.003). Overall, 21 patients had S-100B above reference level (> or =0.10microg/L) and these patients had significantly more calcifications in the ascending aorta on epiaortic scanning.

CONCLUSIONS

Intravenous glutamate infusion during surgery for unstable coronary artery disease did not initiate a sustained elevation of plasma S-100B. Thus, no evidence for subclinical neurological injury related to glutamate infusion was found. In contrast, postoperative elevation of plasma S-100B was linked to calcification of the ascending aorta and postoperative confusion.

Cold blood cardioplegia reduces the increase in cardiac enzyme levels compared with cold crystalloid cardioplegia in patients undergoing aortic valve replacement for isolated aortic stenosis

OBJECTIVES

Cardiac arrest during cardiac surgery is most commonly induced by cold blood or cold crystalloid cardioplegia. The results from clinical studies are divergent regarding which of the 2 solutions provides better myocardial protection. This might be explained by several factors. Both heterogeneity in disease for the included patients and the fact that most studies are retrospective in design and that patients with coronary artery disease with different degrees of myocardial ischemia are included might explain these findings. To circumvent these potentially confounding factors, we included in a prospective randomized study only patients undergoing aortic valve replacement for aortic stenosis without other significant cardiac disease. Patients were randomized to antegrade cold crystalloid or cold blood cardioplegia.

METHODS

Eighty patients with aortic stenosis undergoing aortic valve replacement without significant coronary artery stenosis or other significant concomitant heart valve disease were included in the study. They were randomized to either antegrade cold blood or cold crystalloid cardioplegic solution delivered through the coronary ostia every 20 minutes throughout the period of aortic crossclamping. Maximum postoperative creatine kinase isoenzyme MB and troponin-T levels, well-established markers of myocardial damage, were compared between the 2 groups.

RESULTS

Both maximum postoperative creatine kinase isoenzyme MB and troponin-T levels were significantly higher by approximately 100% in the cohort of patients receiving crystalloid compared with blood cardioplegia. Only in the group of patients receiving cold crystalloid cardioplegia was there a positive correlation between cardiac enzyme levels and crossclamp time.

CONCLUSION

Antegrade cold blood cardioplegia provides better myocardial protection than cold crystalloid cardioplegia in patients undergoing aortic valve replacement.

The use of controlled reperfusion strategies in cardiac surgery to minimize ischaemia/reperfusion damage

Ischaemia and reperfusion occur during almost every cardiac operation, and one of the key elements to achieve a successful operation is to counteract the detrimental effects of induced ischaemia and reperfusion during the operation. The cardiac surgeon is in a unique position to protect the heart before ischaemia is induced and to avoid further damage during the reperfusion period. The surgeon can alter the composition of the reperfusate and the conditions of reperfusion so that the ischaemia/reperfusion injury is minimal, even after very complex procedures that require long aortic cross-clamp periods. This in turn allows him to perform a near-perfect surgical repair of the underlying disease without the pressure of time. The vast knowledge gained in this field over the years has led to application in other organs, such as the limbs (acute limb ischaemia), lungs (lung transplantation), kidney and liver (kidney and liver transplantation), and more recently even for the brain [acute cerebral artery occlusion (stroke)] and the whole body (cardiopulmonary resuscitation). Further improvements in reperfusion strategies will allow salvage of tissue and even whole body after ischaemic periods thought previously to be irreversibly damaged.

Effect of different preoperative patient characteristics on coronary surgery outcome: a comparative study between a developing and a developed country

OBJECTIVES

To evaluate the impact of the preoperative patient characteristics on the results of coronary surgery in a developing country compared with a developed country.

PATIENTS AND METHODS

Preoperative risk factors for coronary artery disease (CAD) and intraoperative and immediate postoperative variables for coronary surgery were compared. Sixty patients were operated at Ain Shams University in Cairo (Egypt) between March and September 1999, compared with 60 patients operated at Hannover medical school (Germany) between March and September 2001. By using univariate analysis and multivariate logistic regression, model predictors for hospital mortality were determined.

RESULTS

Groups were comparable regarding a majority of risk factors except age, diabetes, chronic obstructive pulmonary disease (COPD), and hypertension. Seventy percent of the Egyptian patients presented in New York Heart Association (NYHA) class III, whereas 50% of the German patients were in NYHA class II. Fifty percent of the German patients showed left ventricular ejection fraction (LVEF) >60%, whereas 52% of the Egyptian patients had LVEF between 40% and 59%. Diabetes (56.6%) and COPD (43.3%) are the major predictors of hospital mortality among the Egyptian patients as proved by high odds ratio (4.6 and 3.4, respectively). Egyptian patients required prolonged mechanical ventilation and extended intensive care unit and hospital stay. Hospital mortality was 6.7% in the Egyptian versus 1.7% in the German group.

CONCLUSION

Diabetes mellitus, COPD, and prolonged mechanical ventilation are the major predictors of hospital mortality in Egypt. This study tries to underline problems of coronary artery bypass graft surgery in different populations.

Coronary reoperation with and without cardiopulmonary bypass

Redo coronary artery bypass grafting (CABG) is still associated with increased morbidity and mortality compared to primary operation. Myocardial protection is one of the key issues in redo on pump CABG and is still a matter of debate. Off pump redo CABG seems to be an attractive alternative as native coronary blood flow remains and cross clamping of the aorta is avoided. The aim of this retrospective study was to compare the outcome of redo CABG with and without CPB. From 1/1998 to 5/2004 redo CABG was performed in 195 patients (pts): 162 male (83.1%) and 33 female (16.9%) pts, age 66 +/- 9 years. In 160 pts, CPB with isolated antegrade myocardial protection was used for redo CABG. Off pump redo CABG was performed in 35 pts (30 male (85.7%) and 5 female (14.3%), age 67 +/- 8 years). Perioperative overall mortality rate was 3.6% (n = 7) and comparable in both groups (on pump 3.8% versus off pump 2.9%; p = 0.90), as well as perioperative myocardial infarction, intraaortic balloon pump implantation rate and secondary morbidity. Complete revascularization was achieved in 139 pts (86.9%) after on pump CABG and in 17 pts (48.6%) of the off pump group (p < 0.01). The average number of grafts was significantly higher in the on pump group (2.8 +/- 0.78 versus 1.6 +/- 0.6; p = 0.04).Furthermore, 20 pts (12.5%) in the on pump group died during follow-up (50 +/- 16 months). Five pts (25.0%) died due to cardiac reasons. In the off pump group 3 pts (8.6%) died during follow-up (44 +/- 13 months), noncardiac related. Overall survival was 83.8% in the on pump group and 88.6% in the off pump group (p = 0.92). On pump redo CABG and off pump redo CABG can be safely performed with low mortality and morbidity. Off pump redo CABG might be limited due to incomplete revascularization.

Improved myocardial protection during coronary artery surgery with glucose-insulin-potassium: A randomized controlled trial

OBJECTIVE

We sought to assess the role of glucose-insulin-potassium in providing myocardial protection in nondiabetic patients undergoing coronary artery surgery with cardiopulmonary bypass.

METHODS

A prospective, randomized, double-blind, placebo-controlled trial was conducted at a single-center university hospital performing adult cardiac surgery. Two hundred eighty nondiabetic adult patients undergoing first-time elective or urgent isolated multivessel coronary artery bypass grafting were prospectively randomized to receive glucose-insulin-potassium infusion or placebo (dextrose 5%) before, during, and for 6 hours after surgical intervention. Anesthetic, cardiopulmonary bypass, myocardial protection, and surgical techniques were standardized. The primary end point was postreperfusion cardiac index. Secondary end points were systemic vascular resistance index, the incidence of low cardiac output episodes, inotrope and vasoconstrictor use, and biochemical-electrocardiographic evidence of myocardial injury. The incidence of dysrhythmias and infections requiring treatment was recorded prospectively.

RESULTS

The glucose-insulin-potassium group experienced higher cardiac indices (P < .001) throughout infusion and reduced vascular resistance (P < .001). The incidence of low cardiac output episodes was 15.9% (22/138) in the glucose-insulin-potassium group and 27.5% (39/142) in the placebo group (P = .021). Inotropes were required in 18.8% (26/138) of the glucose-insulin-potassium group and 40.8% (58/142) of the placebo group (P < .001). Fewer patients in the glucose-insulin-potassium group (12.3% [16/133]) versus those in the placebo group (23.4% [32/137]) had significant myocardial injury (P = .017). Noncardiac morbidity was not different.

CONCLUSION

Glucose-insulin-potassium therapy improves early postoperative cardiovascular performance, reduces inotrope requirement, and might reduce myocardial injury. These potential benefits are not at the expense of increased noncardiac morbidity.

Blood cardioplegia

We present the technical details of blood cardioplegia as the standard clinical practice in most centers today. In addition, the contribution refers to the advanced strategies using blood cardioplegia in specific situations, including warm cardioplegia induction, controlled reperfusion in acute myocardial infarction, and the application of leucocyte filtration.

Clinical benefits of continuous leukocyte filtration during cardiopulmonary bypass in patients undergoing valvular repair or replacement

Valve operations in the form of repair or replacement make up a significant population of patients undergoing surgical procedures in the USA annually with the use of cardiopulmonary bypass. These patients experience a wide range of complications that are considered to be mediated by activation of complement and leukocytes. The extracorporeal perfusion circuit consists of multiple synthetic artificial surfaces. The biocompatibility of the blood contact surfaces is a variable that predisposes patients to an increased risk of complement mediation and activation. This can result in an inflammatory process, causing leukocytes to proliferate and sequester in the major organ systems. The purpose of this study was to determine whether filtration of activated leukocytes improved clinical outcomes following surgical intervention for valve repair or replacement. In this paper, we report a retrospective matched cohort study of 700 patients who underwent valve procedures from June 1999 to December 2002. The control group (CG) consisted of patients who had a conventional arterial line filter. In the study group (SG), patients had a conventional arterial line filter and a leukocyte arterial line filter (Pall Medical, NY). In the SG, blood diverted to the cardioplegia system was also leukocyte depleted to enhance myocardial preservation by adapting this device to the outflow port on the filter. Patient characteristics were similar for the SG and the CG, including 228 males and 122 females, mean age (62.4 versus 64.2 years), cardiopulmonary bypass time (127+/-64 versus 116+/-53 min), and aortic crossclamp time (84+/-23 versus 81+/-23 min). Our results demonstrate that the SG achieved statistically significant reduction in the time to extubation (p =0.03) and the number of patients with prolonged intubation in excess of 24 hours (p <0.04), in addition to improved postoperative oxygenation (p=0.01), and decreased length of hospital stay (p =0.03). We believe that leukocyte filters are clinically beneficial, as demonstrated by the results presented in this study.

The effect of oral prednisolone with chronic obstructive pulmonary disease undergoing coronary artery bypass surgery

BACKGROUND

Chronic obstructive pulmonary disease is still one of the most important problems in patients undergoing cardiopulmonary bypass. The purpose of this prospective study was to assess the beneficial effects of oral prednisolone on pulmonary functions in patients undergoing cardiopulmonary bypass.

METHODS

Forty patients with chronic obstructive pulmonary disease were divided into two groups randomly and were given 20 mg oral prednisolone once daily perioperatively (Group I, n = 20) or identical placebo (Group II, n = 20). FEV(1) values, dates of intensive care unit and hospital stays of the two groups were compared.

RESULTS

FEV1 values during the admission to our hospital were similar in each group mean predicted FEV1: 56.7 +/- 5.35% in Group I and 57.2 +/- 4.88% in Group II (p = 0.759). After 10 days of oral prednisolone treatment in Group I, predicted FEV1 values were significantly different between two groups (63.2%+/- 4.24 and 57.9%+/- 4.38) (p = 0.0001). While predicted FEV1 values revealed difference between two groups at the date of discharge (p = 0.0001) the values became similar at the third month (55.6%+/- 4.09 in Group I and 55.45%+/- 3.87 in Group II) (p = 0.897).

CONCLUSION

Various types of complications may occur after cardiopulmonary bypass. Oral prednisolone not only decreases the rates of complications (reintubation, intubation times, and rhythm disturbances) but also decreases the cost of cardiac operations according to shorter hospital stays.

Antegrade administration of cardioplegia

Antegrade cardioplegia remains the single most widespread mode of cardioplegia administration to protect the myocardium for cardiac surgical procedures. It is often used in combination with retrograde cardioplegia. In this article, we describe our method of antegrade blood cardioplegia administration and discuss the advantages as well as the disadvantages of antegrade cardioplegia administration.

Cold blood cardioplegia versus cold crystalloid cardioplegia: A prospective randomized study of 1440 patients undergoing coronary artery bypass grafting

OBJECTIVES

A large number of experimental studies have indicated that blood cardioplegia might be superior to crystalloid cardioplegia for myocardial protection during ischemic arrest. However, no prospectively randomized studies of large patient series have been undertaken to prove potential differences in clinical course.

METHODS

Over a 52-month period, all patients undergoing on-pump coronary artery bypass operated on by 2 surgeons were prospectively randomized to receive either cold crystalloid cardioplegia (group C) or cold blood cardioplegia (group B) during aortic crossclamping.

RESULTS

Altogether, 1440 patients aged 37 to 89 years (median, 66 years) entered the study (group C, n = 719; group B, n = 721). The groups were comparable in all major demographic, preoperative, and operative variables. The clinical course turned out to be nearly identical for both groups. No statistically significant differences were seen concerning spontaneous sinus rhythm after aortic declamping, use of inotropic drugs or intra-aortic balloon pumping, postoperative ventilatory support, bleeding and rate of allogeneic blood transfusions, perioperative myocardial infarction, episodes of atrial fibrillation, stroke or minor neurologic dysfunction, renal function, infections, physical rehabilitation, or mortality. Also, in subgroups of patients at higher operative risk (female sex, age >70 years, unstable angina, diabetes, emergency operation, ejection fraction <0.50, crossclamping time >50 minutes, and EuroSCORE >4), no statistically significant differences could be demonstrated between the groups.

CONCLUSIONS

There were no significant differences whether myocardial protection was performed with cold blood cardioplegia or cold crystalloid cardioplegia during aortic crossclamping in patients undergoing coronary artery bypass grafting. The extra costs related to blood cardioplegia might be saved.

Myocardial Protection in Reoperative Coronary Artery Bypass Grafting:. Toward Decreasing Morbidity and Mortality

Redo coronary artery bypass grafting (CABG) is associated with higher morbidity and mortality when compared to first-time CABG. Myocardial infarction and dysfunction contribute significantly to the increased risk of redo CABG. Results of reoperative coronary surgery have gradually improved, largely because of improvements in myocardial protection techniques. In the present review we will highlight the principles of myocardial protection in redo CABG patients with an emphasis on retrograde cardioplegia.

Hyperkalemic blood versus crystalloid cardioplegia in longer clamping times

The 715 patients who had crystalloid cardioplegia were compared with 5419 who had cold hyperkalemic blood cardioplegia for isolated coronary artery grafting from 1996 through 2001. Creatine kinase-MB was measured preoperatively, at 90 min, and 7 hours after the end of extracorporeal circulation. Correlation of post-bypass creatine kinase-MB release with aortic crossclamp time and other variables in the two cardioplegia groups was made using dichotomous encoding of cardioplegia in a multivariate linear regression model. Creatine kinase-MB levels 90 min after bypass were higher in patients who had crystalloid cardioplegia than in those who had blood cardioplegia. There was a linear relationship between aortic crossclamp time and post-bypass creatine kinase-MB release in both cardioplegia groups. Post-bypass creatine kinase-MB release increased with aortic crossclamp time independently of other factors and significantly more with crystalloid cardioplegia than with blood cardioplegia (the slope of the regression line was 0.230 versus 0.106). Intraaortic balloon pumping was used less frequently in the blood cardioplegia group. There was an advantage with blood cardioplegia for myocardial protection in longer aortic crossclamp times for isolated coronary bypass grafting.

Long-term beneficial effect of coronary artery bypass grafting in patients with COPD

OBJECTIVE

This study assesses the impact of COPD on the long-term outcome of patients undergoing coronary artery bypass grafting (CABG).

METHODS

Between 1991 and 1993, 37 patients (5.68%) undergoing CABG had significant clinical COPD. They were compared to 37 matched control subjects.

RESULTS

The patients in the COPD group had worse preoperative pulmonary function. More patients in this group were smokers, had more symptoms of shortness of breath, and had more preoperative arrhythmia. A total of 13 patients died in the COPD group compared with 3 subjects in the control group during 8.6 +/- 2 years (mean +/- SD) of follow-up with arrhythmia being the major cause of death (62%). Actuarial survival at 9 years was 92% for the control group vs 65% for the COPD group (p = 0.005). The rate of readmissions during mid-term follow-up (13.8 +/- 7.2 months) was higher in the COPD group, and more patients in this group described their quality of life as worse than before the operation (37% vs 3%, p < 0.001). At late follow-up, all survivors in the COPD group had an improved quality of life. Cox regression analysis identified older age and lower FEV(1) as independent predictors of late death. Pulmonary function returned to baseline in the control group and improved to above baseline in the patients with COPD.

CONCLUSIONS

Patients with significant COPD have a higher risk after CABG compared to patients without COPD. Nevertheless, when assessing the natural history of patients with COPD, it seems those who undergo CABG benefit from the operation.

Surgical nurse assistants in cardiac surgery: a UK trainee's perspective

OBJECTIVE

To assess the impact of surgical nurse assistants on surgical training based on a comparative audit of case-mix and outcome of coronary revascularizations assisted by surgical nurse assistants vs. surgical trainees.

METHODS

Relevant recent articles on Calman reform of specialist training and European working time directive (EWTD) on junior doctor working hours were reviewed for the discussion. For the audit prospectively entered data of elective and expedite first time coronary artery bypass grafting cases from 2000 to 2003 were analysed. Group A (n=233, Consultant+Surgical nurse assistant), group B (n=1067, Consultant+Junior surgical trainee). Chi-square test, t-test and Fisher's test were used as appropriate for statistical analysis.

RESULTS

Comparative preoperative variables were gender (P=0.8), body mass index (P=0.9), smoking (P=0.3), diabetes mellitus (P=0.2), hypertension (P=1), peripheral vascular disease (P=0.5), previous cerebrovascular accident (CVA)/transient ischemic attack (TIA) (P=0.3), renal dysfunction (P=0.4), preoperative rhythm disturbances (P=0.3), previous Q-wave myocardial infarction (MI) (P=0.4), Canadian Cardiovascular Society angina class (P=0.4), New York Heart Association heart failure class (P=0.4) and left ventricular function (P=0.4). Patients in group B were of higher risk due to age (P=0.01), coronary disease severity (P=0.05), left main stem disease (P=0.001), Parsonnet score (P=0.0001) and Euroscore (P=0.005. Regarding the myocardial protection technique, intermittent cross-clamp fibrillation was used more frequently in group A while antegrade-retrograde cold blood cardioplegia and off-pump coronary artery bypass were used more in group B (P=0.0001). The cross-clamp (P=0.0001) and operation time (P=0.0001) were significantly lower in group A despite a comparable mean number of grafts (P=0.2). There was no significant difference in the immediate postoperative outcome ventilation time (P=0.2), intensive care unit stay, postoperative stay (P=0.2), re-exploration for bleeding (P=0.5), inotrope+intra-aortic balloon pump (P=0.2), postoperative MI (P=0.9), postoperative rhythm disturbances (P=0.9), CVA/TIA (P=0.8), renal dysfunction (P=0.6), wound infection (P=0.7), sternal re-wiring (P=0.2), multi-organ failure (P=0.4) or mortality (P=0.1).

CONCLUSIONS

Surgical nurse assistants can be used effectively in low-risk cases without compromising postoperative results. However, initiatives to tackle the EWTD should be focused on areas that do not compromise the training needs of junior surgical trainees. An intermediate grade between the present senior house officer and registrar grades could be a way forward.

Subcellular distribution of protein kinase C isozymes during cardioplegic arrest

BACKGROUND

On the basis of the hypothesis that cardioplegia-associated myocardial depression was due to activation of protein kinase C, we examined whether specific protein kinase C isozymes would translocate to a cellular fraction containing myofilaments.

METHODS

Isolated rat hearts were perfused with Krebs-Ringer bicarbonate buffer for 30 minutes and arrested with 4 degrees C St Thomas No. 2 cardioplegic solution for 0 to 120 minutes (n = 5 per group). The 3 fractions of the left ventricle tissue represented the myofibrillar/nuclear fraction (P1), membranes (P2), and cytosol (supernatant). The distributions of protein kinase C isozymes alpha, delta, epsilon, and eta were examined after separation by electrophoresis, immunoblotting/chemiluminescence, and densitometry.

RESULTS

A significant increase in protein kinase C-delta in the P1 fraction was detected after 5 minutes of cardioplegic arrest and remained increased for 60 minutes. Increases in P1 protein kinase C-alpha and -epsilon were seen transiently at 5 minutes, and protein kinase C-epsilon demonstrated a secondary increase in P1 at 30 to 60 minutes. There was also a significant relative increase in protein kinase C-alpha and protein kinase C-delta in the P2 fraction after 60 minutes of cardioplegia.

CONCLUSIONS

These data are consistent with our hypothesis that activation of protein kinase C isozymes is associated with altered myofilament function after cardioplegic arrest.

Outcome and complications of intraoperative hemodialysis during cardiopulmonary bypass with potassium-rich cardioplegia

BACKGROUND

Potassium-rich cardioplegia has advantages over other cardioplegic solutions in preserving the myocardium during cardiopulmonary bypass, but it is avoided in patients with renal failure because of hyperkalemia.

METHODS

We first determined the ability of intraoperative hemodialysis (IHD) to remove potassium during cardiopulmonary bypass with potassium-rich cardioplegia in 9 patients by measuring potassium levels in all dialysate and urine. We then studied 24 patients with renal failure, grouped with the 9 previous patients, to assess safety, rebound hyperkalemia, and patient outcome with this technique.

RESULTS

In the first phase, 9 patients were administered 128 +/- 11 mmol of potassium in potassium-rich cardioplegia, and IHD removed 157 +/- 23 mmol. Urinary potassium excretion was only 10 +/- 3 mmol. Potassium removal occurred at a rate of 1.25 mmol/min with 0-mEq/L (mmol/L) potassium dialysate and a rate of 0.75 mmol/min with 3.0-mEq/L (mmol/L) potassium dialysate. In all 33 patients, successful initiation of cardiac rhythm occurred after cardiopulmonary bypass, and 5 patients had cardiac arrhythmias possibly from hypokalemia. In the next 24 hours, 5 dialysis-dependent patients developed hyperkalemia (potassium > 5.2 mEq/L [mmol/L]) requiring hemodialysis. Postoperative hemodialysis was delayed 2 to 3 days in the other patients. The overall death rate was 24% at 30 days.

CONCLUSION

IHD effectively and safely removes potassium administered during potassium-rich cardioplegia during cardiopulmonary bypass in patients with renal failure and prevents postoperative hyperkalemia in the majority of patients. Overall mortality in patients with acute and chronic renal failure undergoing cardiac surgery is high irrespective of control of potassium balance in these patients.

Single aortic clamp versus partial occluding clamp technique for cerebral protection during coronary artery bypass: a randomized prospective trial

Single aortic clamp (SAC) versus partial occluding clamp (POC) technique for the construction of proximal anastomosis has been suggested to provide better cerebral protection during coronary artery bypass grafting (CABG). The aim of this study was to assess this hypothesis in a prospective randomized trial.

METHODS

Two hundred sixty-eight consecutive patients underwent CABG at a single institution. All patients were randomized to either SAC (Group S) or POC (Group P) for the construction of the proximal anastomosis. Myocardial protection consisted of multidose antegrade cold blood cardioplegia with topical cooling. The operations were performed using standard cardiopulmonary bypass support and moderate systemic hypothermia (29 to 32 degrees C). The incidences of neurological events, perioperative myocardial infarction (MI), and mortality were prospectively evaluated.

RESULTS

The two groups were similar in mean age, gender, urgency of operation, and number of bypasses. Group S patients had a significantly longer cross-clamp (61 +/- 21 minutes [S] vs 44 +/- 13.8 minutes [P], p < 0.05) and bypass times (85 +/- 25 minutes [S] vs 74 +/- 19.7 minutes [P], p < 0.05). There were no differences in the number of perioperative MIs (Group S = 3 [2.3%]; Group P = 2 [1.5%], p = 0.50) or mortality (Group S = 2 [1.5%]; Group P = 3 [2.2%], p = 0.50). Two patients randomized to POC were switched to SAC intraoperatively because of severe calcification of the ascending aorta. In Group P, there were two strokes (1.5%) and two (1.5%) postoperative confusions versus none in Group S (relative risk = 2.0, p < 0.05, respectively).

CONCLUSION

The SAC technique improved cerebral protection without any adverse effect on myocardial protection and postoperative outcome in patients undergoing CABG.

Continuous retrograde blood cardioplegia is associated with lower hospital mortality after heart valve surgery

OBJECTIVE

Myocardial preservation studies comparing blood and crystalloid cardioplegia techniques were almost exclusively performed on patients undergoing coronary bypass, and they were unable to show a difference in hospital mortality. We investigated possible factors, including cardioplegia techniques, influencing hospital mortality in patients undergoing cardiac valve surgery.

METHODS

We evaluated hospital mortality in 1098 consecutive patients undergoing cardiac valve surgery by using a multivariate logistic regression with propensity score balancing of the groups. In 25% of the patients, multiple valve or Bentall procedures were performed, and in 46% of all patients, coronary bypass grafting was associated with valve surgery. A first cohort of 504 consecutive patients were operated on by using single-shot antegrade cold crystalloid cardioplegia, and a second cohort of 594 patients were operated on by using continuous retrograde cold blood cardioplegia.

RESULTS

After correction for patient-related and operative risk factors, lower hospital mortality was found in patients who received retrograde blood cardioplegia (P =.020). The odds ratio of in-hospital death when using blood cardioplegia was 0.44 (95% confidence interval, 0.22-0.88). Further predictors of hospital mortality were age, advanced New York Heart Association functional class, cardiopulmonary bypass time, reoperation, active endocarditis, and renal failure.

CONCLUSIONS

This study shows that continuous retrograde blood cardioplegia is associated with lower hospital mortality in heart valve operations.

Myocardial protection: entering the new millennium

Dual objectives at operation are technical success and absence of iatrogenic injury due to inadequate myocardial protection. We enter a new millennium, and the spectrum of surgical procedures used to correct abnormal structure is expanding. We need longer intervals of aortic clamping to make the correct diagnosis, and to implement a more natural correction (i.e., mitral valve repair, Ross procedure, aortic recontruction with stentless valves, homografts). Simultaneously, our patients have increased vulnerability to injury, so that growth is needed to advance our methods of protection, in the same way as we learn new operative techniques. This manuscript deals both with evolution of current methods and recognition of newer methods of protection, so that the dual relationship between protection and procedures will not separate.

Cardiac marker responses to coronary artery bypass graft surgery with cardiopulmonary bypass and aortic cross-clamping

OBJECTIVE

To study several markers of myocardial injury in relation to aortic cross-clamping and cardiopulmonary bypass (CPB) after coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective observational study.

SETTING

University hospital.

PARTICIPANTS

Thirty adult patients who underwent elective CABG surgery with aortic cross-clamping and CPB.

MEASUREMENTS AND MAIN RESULTS

Serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8), troponin-T (TnT), myosin light chain I (MLCI), and MB isoenzyme of creatine kinase (CK-MB), as markers of myocardial injury, were measured after induction of anesthesia for baseline values, then again at the end of surgery and on postoperative days 1, 3, and 5. IL-6, IL-8, and CK-MB levels were significantly elevated in the early postoperative stage. TnT significantly increased from the end of surgery to postoperative day 5. MLCI increased also but later than TnT. Aortic cross-clamping time correlated positively with peak TnT (r = 0.51, p < 0.05), TnT level on postoperative day 1 (r = 0.69, p < 0.01), and MLCI level on postoperative day 5 (r = 0.45, p < 0.05). CPB time was correlated only with peak TnT (r = 0.47, p < 0.05).

CONCLUSIONS

The increase in TnT level is strongly related to aortic cross-clamping.

Prediction of coronary artery disease in patients undergoing operations for mitral valve degeneration

OBJECTIVES

We sought to develop and validate a model that estimates the risk of obstructive coronary artery disease in patients undergoing operations for mitral valve degeneration and to demonstrate its potential clinical utility.

METHODS

A total of 722 patients (67% men; age, 61 +/- 12 years) without a history of myocardial infarction, ischemic electrocardiographic changes, or angina who underwent routine coronary angiography before mitral valve prolapse operations between 1989 and 1996 were analyzed. A bootstrap-validated logistic regression model on the basis of clinical risk factors was developed to identify low-risk (< or =5%) patients. Obstructive coronary atherosclerosis was defined as 50% or more luminal narrowing in one or more major epicardial vessels, as determined by means of coronary angiography.

RESULTS

One hundred thirty-nine (19%) patients had obstructive coronary atherosclerosis. Independent predictors of coronary artery disease include age, male sex, hypertension, diabetes mellitus,and hyperlipidemia. Two hundred twenty patients were designated as low risk according to the logistic model. Of these patients, only 3 (1.3%) had single-vessel disease, and none had multivessel disease. The model showed good discrimination, with an area under the receiver-operating characteristic curve of 0.84. Cost analysis indicated that application of this model could safely eliminate 30% of coronary angiograms, corresponding to cost savings of $430,000 per 1000 patients without missing any case of high-risk coronary artery disease.

CONCLUSION

A model with standard clinical predictors can reliably estimate the prevalence of obstructive coronary atherosclerosis in patients undergoing mitral valve prolapse operations. This model can identify low-risk patients in whom routine preoperative angiography may be safely avoided.

Early discharge after coronary artery bypass graft surgery: are patients really going home earlier?

OBJECTIVE

This study was undertaken to determine whether early discharge after coronary artery bypass grafting allows patients to return home earlier or merely increases the use of outpatient nursing and inpatient rehabilitation services.

METHODS

Patterns of discharge were analyzed in 407 patients undergoing bypass grafting in 1990, when there were no early extubations or fast track protocols, and compared with 379 patients in 1998, when these protocols were used.

RESULTS

Patients in 1998 had a higher prevalence of class IV angina (35.3% vs 22.8%; P =.006), urgent/emergency surgery (58.3% vs 44.9%; P =.015), and lower ejection fractions (48.9% +/- 16.4% vs 52.9% +/- 13.5%; P =.0002). Despite these increased risk factors, 1998 patients spent less time receiving ventilatory support (10.2 +/- 9.2 vs 26.7 +/- 15.7 hours; P <.001) and had a shorter length of stay (5.4 +/- 2.5 vs 9.2 +/- 4.3 days; P <.001). However, fewer 1998 patients were discharged home (56.7% vs 97.0%; P <.0001). A higher percentage of 1998 patients (43.3% vs 2.9%; P <.00001) were discharged to extended care facilities where their average length of stay was 10.6 +/- 15.1 days. Readmission to the Boston Medical Center was also more common in 1998 patients (5.3% vs 0.5%; P <.0001).

CONCLUSIONS

Early extubation and fast track protocols have resulted in earlier discharge from acute care facilities. However, the anticipated earlier return to home has been offset by the increased use of outpatient nursing services, discharges to extended care facilities, and hospital readmissions.

Neurological injury after surgery for ischemic heart disease: risk factors, outcome and role of metabolic interventions

OBJECTIVES

Neurological complication remains a feared and increasing problem in association with cardiac surgery. The aim of this study was to analyze risk factors for neurological complications in a cohort of patients in whom inotropes for weaning from cardiopulmonary bypass was gradually replaced by metabolic treatment.

METHODS

The records of 775 consecutive patients undergoing coronary artery bypass grafting (CABG) or combined CABG+valve procedures were examined. Forward stepwise multiple logistic regression analysis was used for statistical evaluation of independent risk factors.

RESULTS

The incidence of neurological injury was 1.8% in patients undergoing isolated CABG and 5.4% after combined CABG+valve procedures. After cross-validation multivariate analysis identified history of cerebrovascular disease, advanced age and aortic cross-clamp time as independent risk factors for postoperative cerebral complications. Chronic obstructive pulmonary disease and number of bypasses also emerged as risk factors in the primary analysis.

CONCLUSIONS

In general, markers for advanced atherosclerosis, with history of cerebrovascular disease as the most important, emerged as predictors for neurological injury. Although it did not enter the final risk model, the results also suggest that postoperative heart failure deserves further surveillance as a potential risk factor for neurological complications. However, no evidence for untoward neurological effects associated with glutamate or glucose-insulin-potassium treatment was found.

Single aortic cross-clamp technique reduces S-100 release after coronary artery surgery

BACKGROUND

Neurologic impairment after coronary artery bypass grafting is associated with cerebral embolization. An important cause of embolism is aortic manipulation. Constructing both distal and proximal anastomoses during a single period of aortic cross-clamping avoids this source of embolism and may reduce neurologic injury after coronary artery bypass grafting.

METHODS

Fifty consecutive patients undergoing coronary artery bypass grafting were prospectively randomized to group 1, in which a single aortic cross-clamping was used to construct distal and proximal anastomoses, or to group 2, in which the proximal anastomoses were each constructed with a partial occluding aortic clamp. Levels of S-100 and troponin-T release were measured preoperatively and postoperatively.

RESULTS

Aortic cross-clamp time was significantly longer in group 1, but other preoperative and intraoperative variables were equally represented in both groups. Control group levels of S-100 and troponin-T were similar. Postoperative S-100 levels were significantly higher in group 2 than in group 1 (p < 0.015). No significant difference was found between the groups in postoperative troponin-T levels.

CONCLUSIONS

The results of this trial suggest improved cerebral protection is associated with the single aortic cross-clamp technique for coronary artery bypass grafting with no increase in myocardial damage. The single aortic cross-clamp technique is simple and inexpensive. We recommend its wider use.

Cardioplegia solutions--unproven herbal approach versus tested scientific study

Cardioplegic solutions are used throughout the world, but must undergo careful testing before their clinical application. This study points out the importance of recognizing the hemodynamic changes produced by tested solutions so that appropriate decisions can be made in selecting crystalloid or blood solutions. Examples are provided, in which arbitrary changes made by the well-intentioned surgeon can produce damage through unanticipated alterations that are introduced without prior testing, and then used clinically. Recognition of the advantages and disadvantages of each solution is the underpinning of selection for clinical use so that unanticipated misadventures do not occur. Furthermore, the importance of making solutions in pharmacies with good manufacturing practices can avoid causing problems that would otherwise be prevented. Fundamentally, cardioplegic solutions are direct cardiac medications that must be tested as other drugs are so that unforeseen problems are avoided.

Overview: procedure versus protection: an impossible separation

This overview focuses upon the fundamental cohesion between myocardial protection and mechanical repair for surgical success. Currently, our attention is directed toward the natural evolution of more complex surgical methods, while there is slower rise in interest in advanced methods of protection. The absence of manuscripts on myocardial protection in major meetings suggests that the concept of protection has been solved, even though there remain reports of use of intraaortic balloon and mechanical devices that appear when protection is inadequate. This Seminar volume will introduce a series of articles about risk patients for whom evolving methods of protection are used. We will point out frontiers of protection that should develop together with advances in technical surgical approaches so that these two essential components that insure the safe conduct of cardiac operations can grow together.

The role of integrated myocardial management in reoperative coronary surgery

This article identifies the effect of integrated myocardial protection on outcomes after first-time repeat coronary artery bypass grafting (CABG). A consecutive series of 124 repeat CABG procedures were performed between January 1996 and December 1999 with single aortic cross-clamping for all anastomoses and integrated myocardial protection. This included ischemia for heart dissection and distal grafting, and perfusion throughout the remainder of aortic clamping (including warm/cold, substrate/nonsubstrate-enhanced blood cardioplegia, delivered antegrade/retrograde, continuously/intermittently). Mean patient age was 67 +/ - 10 years (median 68) with 61% in New York Heart Association class IV and 23% in class III. Mean ejection fraction (EF) was 45 +/- 10.6% with EF 40% or less in 33% of patients and 30% or less in 20%. An average of 2.5 +/- 0.9 grafts were constructed. Cross-clamp times averaged 72 +/- 22 min and cardiopulmonary bypass time averaged 91 +/- 27 min. The average time from release of cross-clamp it disconnection from cardiopulmonary bypass (CPB) was 10 min. Median postoperative hospital stay was 6 days. hospital mortality was 2.4%, intra-aortic balloon pump (IABP) use 3.2%, stroke 0.8%, atrial fibrillation 11%, and reexploration for bleeding 2.4%. Integrated myocardial protection with blood cardioplegia is safe during reoperative coronary surgery. It allows rapid separation from CPB, limited IABP use, and low morbidity and mortality.

Continuing controversy in the management of concomitant coronary and carotid disease: an overview

OBJECTIVES

To perform an analytical overview of the risk factors, pathogenesis of stroke and the strategies for the management of concomitant coronary artery disease and carotid artery stenosis (CAS). Four strategies were analysed; CABG in the presence of CAS, combined (CE+CABG), reverse (CABG+CE<3 months) and prior staged (CE+CABG<3 months).

METHODS

A literature search formed the basis of a reference database. Outcome was assessed by the 30-day permanent stroke and mortality rate for the different approaches. Accrued rates of permanent stroke and mortality rate were expressed in terms of mean stroke and mortality rate (MSR, MMR). Data was analysed comparatively and expressed in terms of P value, odds ratio and confidence limits.

RESULTS

33 different risk factors for stroke at CABG were identified. Significant factors included: ascending aortic atheroma, emergency procedures, impaired left ventricular function, cardioplegia and peripheral vascular disease. Risk of stroke at CABG increased with higher grade CAS (50 vs. 80%, P=0.009). Pathogenesis of stroke at CABG is multifactorial; the role of flow limiting CAS is controversial and other mechanisms are implicated. Analysis of the four strategies revealed that in the Prior Stage (n=573) the MSR was 1.5% and MMR 5.9%, in the Unprotected CABG+CAS series the MSR was 3.8% (n=840) and MMR (n=596) 4.4%, in the Reverse stage series (n=83) the MSR was 2.4%, and MMR 4.8%. For Combined procedures (n=3,295) the MSR was 3.9% and MMR 4.5%. Comparative analysis indicated a significant reduction in stroke for Prior vs. Combined (1.5 vs. 3.9%, P=0.007, odds 0.39, CI 0.2-0.77) with a higher mortality (5.9 vs. 4.5%, P=0.1, odds 1.41, Cl 0.96-2.06, NS). The stroke rate in the Prior stage also remained significantly lower compared to the Unprotected CABG group both mixed (P=0.015) and asymptomatic CAS (P=0.047). When total risks (MSR+MMR), were analysed, similar results were found between the groups; Prior 7.4%, Reverse stage 7.2%, Combined 8.4%, Unprotected CABG+ >50% CAS 11.5%.

CONCLUSIONS

Stroke at CABG is due to multiple risk factors, one of which is high-grade carotid stenosis. Pathophysiology of stroke, although multifactorial, supports embolism rather than flow limitation as the primary mechanism. Lack of randomised trials has made it impossible to draw firm conclusions regarding the best management strategy. There was no significant difference in the overall stroke and mortality risk between the various strategies, however, subgroup analysis suggests that, when carefully selected, patients do better by staging the operations. In our opinion patients without severe cardiac disease should be considered for Prior staging and the rest for Combined procedure. The role of reverse staging needs further evaluation.

Atrial fibrillation independently prolongs hospital stay after coronary artery bypass surgery

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia occurring in patients after coronary artery bypass surgery (CABG).

HYPOTHESIS

The purpose of this study was to determine whether AF independently prolonged postoperative length of stay (LOS).

METHODS

Consecutive patients undergoing elective CABG were identified. Baseline clinical variables, postoperative course including the development of AF, and postoperative LOS were recorded.

RESULTS

In all, 216 patients (aged 61 +/- 13 years) were examined. Postoperative LOS was 11.3 +/- 6.4 days (median LOS = 9 days). Fifty-five patients (25%) developed AF. Among 16 variables examined, the univariate predictors of LOS included age (p < 0.001), preoperative left ventricular ejection fraction (p < 0.001), absence of a prior smoking history (p < 0.05), bypass limited to venous conduits (p < 0.001), postoperative AF (p < 0.001), and the occurrence of a postoperative event (p < 0.001). Length of stay for patients who developed AF was significantly longer than that for patients who did not (15.1 +/- 9.0 vs. 10.0 +/- 4.6 days, p < 0.001). After adjusting for other significant variables, the occurrence of AF after CABG independently prolonged LOS: patients who developed AF stayed 3.2 +/- 1.7 days longer than patients who did not (p < 0.001).

CONCLUSIONS

Atrial fibrillation lengthens hospital stay after CABG, and its effect is independent of other important variables. Identification of patients who are at risk for AF and successful treatment to prevent AF will likely contribute to major reductions in consumption of health care resources in patients with CABG.

Terminal warm blood cardioplegia improves the recovery of myocardial electrical activity. A retrospective and comparative study

OBJECTIVE

The effect of terminal warm blood cardioplegia was analyzed in 191 patients undergoing either coronary artery bypass grafting (CABG) or prosthetic heart valve replacement between Jan. 1990 and Dec. 1995.

METHODS

Patients were subdivided into 3 historical cohorts based on the method of myocardial protection: Group A (n = 106), multidose cold crystalloid glucose-potassium cardioplegia, alone; Group B (n = 37), cold crystalloid glucose-potassium cardioplegia plus terminal warm blood cardioplegia, Group C (n = 48), cardioplegia induction with cold crystalloid glucose-potassium cardioplegia, maintenance with multidose cold blood cardioplegia, and terminal warm blood cardioplegia.

RESULTS

Of patients undergoing CABG, 5.6% of group A, 70.4% of group B, and 86.7% of group C spontaneously resumed sinus rhythm after aortic declamping, as did 9.1% of group A, 60.0% of group B, and 55.6% of group C of patients undergoing prosthetic heart valve replacement. The incidence of spontaneous recovery was significantly better in groups B and C than in group A (p < 0.05). Over 90% of patients without terminal warm blood cardioplegia developed ventricular fibrillation or tachycardia requiring electrical cardioversion (p < 0.05). Postoperatively, patients without terminal warm blood cardioplegia required temporary epicardial pacing more frequently than those with terminal warm blood cardioplegia (p < 0.05). In patients undergoing prosthetic heart valve replacement, groups B and C, the incidence of postoperative atrial fibrillation was significantly lower than in group A.

CONCLUSION

Terminal warm blood cardioplegia thus promoted better postoperative electrophysiological cardiac recovery.