Pulmonary embolus after coronary artery bypass surgery: a review of the literature

A comprehensive deep venous thrombosis prophylaxis regimen in isolated coronary artery bypass grafting

Objectives

Deep venous thrombosis (DVT) is a known surgical complication that can lead to pulmonary embolism with subsequent morbidity and mortality. The incidence of DVT following coronary artery bypass grafting is unclear. Prophylaxis regimens vary and some guidelines advocate against use of routine chemoprophylaxis in patients at low-moderate risk for venous thromboembolism. We utilized postoperative lower extremity venous ultrasound to determine the incidence of DVT following coronary artery bypass grafting in patients with low- to moderate-risk of venous thromboembolism receiving aggressive postoperative DVT prophylaxis.

Methods

This is a single-center, retrospective study of all patients who underwent coronary artery bypass grafting between April 2022 and January 2023. All patients who completed postoperative venous ultrasound of the bilateral lower extremities were initially included. Patients who underwent concurrent valve or aortic surgery, were at high risk of venous thromboembolism, or were receiving anticoagulation therapy for nonvenous thromboembolism indications were excluded. The primary outcome was in-hospital incidence of DVT. Secondary outcomes were rates of mortality, postoperative bleeding, and thromboembolic events from discharge to 30 days postoperatively and from 30 days to 3 months postoperatively.

Results

No DVTs were observed in 211 included patients. In hospital, there were 3 significant bleeding events and 1 stroke. Following discharge there were 3 additional bleeding events, 1 death, 1 transient ischemic attack, and 1 pulmonary embolism.

Conclusions

We observed a 0% rate of DVT in low- to moderate-risk patients undergoing isolated coronary artery bypass grafting and receiving a comprehensive DVT prophylaxis regimen. In hospital bleeding and other thromboembolic event rates were 2.84% and 0.47% respectively.

Routine early postoperative computed tomography angiography after coronary artery bypass surgery: clinical value and management implications

OBJECTIVES

Computed tomography angiography (CTA) is broadly used for long-term follow-up of graft patency after coronary artery bypass graft surgery (CABG). However, its clinical value in the early postoperative setting has not been established yet. We evaluated the benefit of adding CTA to the routine clinical work-up after CABG on patient management.

METHODS

A total of 305 consecutive patients (269 males, median age 68 years) underwent CABG and postoperative CTA with a median of 6 days after surgery. Graft patency and additional imaging findings were assessed and their influence on diagnosis and clinical management was evaluated.

RESULTS

Graft occlusion or high-grade stenosis was found in 15% of the patients. Additional findings were reported in 44% of the patients, including pericardial (2%) and pleural effusion (27%), large pneumothorax (11%), pulmonary infection (4%), cardiac or vascular thrombus (2%), pulmonary embolism (2%), sternal dehiscence (1%) and additional incidental findings requiring follow-up (6%). CT findings initiated new diagnostic and/or therapeutic measures in 15% of the patients, 47% of those with diseased grafts and 19% of patients with non-graft-related findings. No adverse events related to CTA were documented.

CONCLUSIONS

Early routine postoperative assessment of CABG with CTA reveals both cardiac and non-cardiac findings with a high frequency, affecting clinical management in a substantial proportion of patients.

Prevention of Pulmonary and Venous Thromboembolism Post Coronary Artery Bypass Graft Surgery - Literature Review

Objective

The current review evaluates recent literature on the different aspects of prophylaxis in postoperative pulmonary and venous thromboembolism and their main risk factors.

Methods

The literature survey was carried out based on the PubMed data using the keywords “coronary artery bypass graft” and “venous thromboembolism” as components of the search field title.

Results

Studies reported several risk factors for postoperative thromboembolism including advanced age, postoperative immobilization, type of thromboprophylaxis, obesity, and location of the surgery.

Conclusion

According to the studies, tailored prophylaxis could be easily adapted to decrease the intensity and duration of postoperative thromboembolism in a patient with several disorders and comorbidities, especially in cardiovascular disease.

Bleeding complications after cardiac surgery, before anticoagulation start and then with argatroban or heparin in the early postoperative setting

OBJECTIVES

After elective cardiac surgery a postoperative anticoagulation is obligatory. With critically ill patients the conventional anticoagulation standard heparin is sometimes impossible, e.g. based on HIT II. Then, argatroban is currently a possible alternative, however, due to its impaired metabolism in critically ill patients, anticoagulation effect is harder to anticipate, thus resulting in higher bleeding risk. Furthermore, to date no antidote is available. Hence, severe postoperative bleeding incidents under anticoagulation are commonly mono-causal attributed to the anticoagulation itself. This study concentrates on the number of well-defined postoperative bleeding incidents before any anticoagulation started, then actually under argatroban as well as compared to those under heparin (or switched from heparin to argatroban).

MATERIAL AND METHODS

Retrospective study including 215 patients undergoing elective cardiac surgery with a postoperative stay in ICU ≥48 h. Postoperative bleeding complications before and after start of anticoagulation were evaluated. Definition of bleeding complications were: decrease of hemoglobin by more than 2 g/dl without dilution (mean value of volume balance plus one standard deviation) and/or increased need of red blood cell transfusion/day (average transfusion rate + 2 standard deviations).

RESULTS

Within the study group of 215 patients, 143 were treated with heparin, 43 with argatroban, 29 switched from heparin to argatroban. Overall, 26.5% (57/215) postoperative bleeding complications occurred. In 54.4% (31/57) bleeding complications occurred before start of anticoagulation; in 43.6% (26/57) after. Of these, 14 bleeding incidents occurred under heparin 9.8% (14/143), 6 under argatroban 14% (6/43) and 6 switched 20.7% (6/29). Higher bleeding complications before start of anticoagulation was related to concomitant factors influencing the overall bleeding risk; e.g. score of severity of illness. These observations further correlate with postoperative, but not anticoagulation induced mortality rate of 2.8% of then given heparin, 20.9% then argatroban, 20.7% then switched.

CONCLUSIONS

Postoperative bleeding complications cannot simply be attributed to anticoagulation since occurring often before anticoagulation was started. The risk for bleeding complications after start of anticoagulation was quite comparable for argatroban and heparin. Accordingly, the influence of argatroban on bleeding complications in the postoperative period may be less significant than previously thought.

Association of Acute Venous Thromboembolism With In-Hospital Outcomes of Coronary Artery Bypass Graft Surgery

Background

While venous thromboembolism (VTE) prophylaxis is a strong recommendation after most surgeries, it is controversial in cardiac surgeries such as coronary artery bypass grafting (CABG), because of perceived low VTE incidence and increased bleeding risk. Prior studies may not have been adequately powered to study outcomes of VTE in this population. We sought to investigate the postoperative incidence and outcomes of CABG patients using a large national inpatient database.

Methods and Results

We utilized the 2013 to 2014 National Inpatient Sample to identify all patients >18 years of age who underwent CABG (without concomitant valvular procedures), and had VTE during the hospital stay. We then compared clinically relevant outcomes in patients with and without VTE. We identified 331 950 CABG procedures. Of these, 1.3% (n=4205) had VTE. Patients with VTE were more likely to be older (mean 67.2±10.4 years versus 65.2±10.4 years, P<0.001). VTE was associated with higher incidence of inpatient mortality (6.8% versus 1.7%; adjusted odds ratio 1.92 [95% CI 1.40–2.65]; P<0.001) and complications. VTE was also associated with higher cost (mean±SE $81 995±$923 versus $48 909±$55) and longer length of stay (mean±SE 17.06±0.16 days versus 8.52±0.01 days).

Conclusions

Our analysis of >330 000 CABG procedures suggests that while postoperative VTE after CABG is rare, it is associated with increased morbidity and mortality. Randomized controlled trials are needed to identify optimal strategies for VTE prophylaxis in these patients.

Acute Pulmonary Embolectomy Three Days following a Coronary Artery Bypass Graft Procedure

Pulmonary embolism is very rarely reported early after cardiac surgery, most probably due to full heparinisation during cardiopulmonary bypass. We report a 66-year-old man without thromboembolic history who presented three days after a coronary artery bypass grafting procedure with acute dyspnoea and haemodynamic instability. A CT scan confirmed paracentral bilateral pulmonary embolism requiring an urgent and successful embolectomy. Review of the literature confirms that pulmonary embolism may occur in up to 3% of post-cardiopulmonary bypass patients.

The possibility of pulmonary embolism must be taken into consideration in post-cardiopulmonary bypass patients with acute onset of chest pain and respiratory insufficiency.

Causes of Dyspnea after Cardiac Surgery

OBJECTIVES

Postoperative dyspnea is common after cardiac surgery, even in low-risk patients. Cardiac surgeons and anesthesiologists are familiar with patients suffering from dyspnea in the early postoperative period, but in some cases, conventional treatment strategies may be ineffective, and a consultation with a pulmonologist may be required. The aim of this study is to investigate the causes of dyspnea after cardiac surgery in this particular patient group.

MATERIALS AND METHODS

The hospital database was searched for non-emergency cardiac surgery for the period January 2014-October 2015. Individuals with an impaired spirometry result and a history of any pulmonic disease were excluded. Only patients for whom a pulmonary consultation was needed because of dyspnea in the postoperative course were enrolled in the study. Causes of dyspnea were analyzed according to consultation reports and computed tomography findings.

RESULTS

One hundred and three patients were enrolled in the study. Of those, 67 (65%) were male, and the mean age was 61.50±9.43. The most common procedure was the coronary artery bypass grafting. Atelectasis (n=57, 42%) was the most common cause of dyspnea. The length of the intensive care unit (ICU) stay was significantly longer in the pneumonia group (p=0.012). Hospital mortality in the pneumonia group was significantly higher compared with other subgroups (p<0.001).

CONCLUSION

After cardiac surgery, atelectasis was the most common cause of dyspnea, followed by pleural effusion and pneumonia. Patients who experienced dyspnea due to pneumonia had a longer ICU stay. Developing the treatment strategies with consideration of these causes may help reduce the length of stay, morbidity, and mortality in this patient group.

Coronary artery bypass graft surgery complications: A review for emergency clinicians

INTRODUCTION

Coronary artery bypass graft (CABG) surgery remains a high-risk procedure, and many patients require emergency department (ED) management for complications after surgery.

OBJECTIVE

This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of post-CABG surgery complications.

DISCUSSION

While there has been a recent decline in all cardiac revascularization procedures, there remains over 200,000 CABG surgeries performed in the United States annually, with up to 14% of these patients presenting to the ED within 30 days of discharge with post-operative complications. Risk factors for perioperative mortality and morbidity after CABG surgery can be divided into three categories: patient characteristics, clinician characteristics, and postoperative factors. Emergency physicians will be faced with several postoperative complications, including sternal wound infections, pneumonia, thromboembolic phenomena, graft failure, atrial fibrillation, pulmonary hypertension, pericardial effusion, strokes, renal injury, gastrointestinal insults, and hemodynamic instability. Critical patients should be evaluated in the resuscitation bay, and consultation with the primary surgical team is needed, which improves patient outcomes. This review provides several guiding principles for management of acute complications. Understanding these complications and an approach to the management of hemodynamic instability is essential to optimizing patient care.

CONCLUSIONS

Postoperative complications of CABG surgery can result in significant morbidity and mortality. Physicians must rapidly diagnose these conditions while evaluating for other diseases. Early surgical consultation is imperative, as is optimizing the patient's hemodynamics, including preload, heart rate, cardiac rhythm, contractility, and afterload.

Incidental Pulmonary Embolism After Coronary Artery Bypass Surgery: Long-Term Clinical Follow-Up

OBJECTIVE

The purpose of this study was to investigate the incidence and natural history of incidentally found and untreated pulmonary embolism (PE) at coronary CT angiography after coronary artery bypass grafting.

MATERIALS AND METHODS

We retrospectively reviewed the records of 353 patients consecutively registered between January 1, 2010, and November 11, 2015, who underwent coronary artery bypass grafting followed within 2 weeks by coronary CT angiography. All patients received 100 mg of aspirin and 75 mg of clopidogrel after surgery. We collected relevant clinical and CT data, including total follow-up duration after coronary artery bypass grafting, follow-up CT findings, mortality, and incidence of any recurrent PE.

RESULTS

PE was diagnosed in 22 of the 353 patients (6.2%) who remained in the study after the exclusion criteria were applied. Most of the PEs occurred at the segmental or subsegmental level. All patients were in hemodynamically stable condition, had no symptoms, and underwent follow-up for a median of 53 months (range 19-74 months). Twenty of the 22 patients did not receive anticoagulation, and all but one of these patients had complete resolution of PE at second follow-up coronary CT angiography (median, 149 days after surgery). There was no associated mortality or recurrent PE.

CONCLUSION

Incidental PE after coronary artery bypass grafting is found in approximately 6% of patients undergoing postoperative coronary CT angiography, and most PEs resolve spontaneously without anticoagulation. No patient in this study died or had recurrent PE during a median follow-up period of 53 months.

Frequency of Deep Vein Thrombosis and/or Pulmonary Embolism After Coronary Artery Bypass Grafting Investigation Regardless of Clinical Suspicion

Venous thromboembolism (VTE) includes deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Many surgeons and clinicians believe that VTE after coronary artery bypass grafting (CABG) has little clinical significance because it is seldom diagnosed. This study aimed to identify VTE after CABG, independent of clinical suspicion. In this prospective, observational, single-center study, 100 patients underwent computed tomographic pulmonary angiography (multidetector-64) and lower extremity venous compressive ultrasound after elective CABG. Patients with high risk for VTE were excluded. Aspirin was maintained throughout the preoperative and postoperative periods, and early ambulation was encouraged. Postoperatively, no mechanical or heparin prophylaxis was used in any patients. At the discretion of the surgeons, 83 surgeries were on-pump, and 17 were off-pump. On average, tomography and ultrasound were performed 7 ± 3 days after CABG. Isolated PE was observed in 13 of 100 patients (13%), simultaneous PE and DVT in 8 of 100 (8%), and isolated DVT in 4 of 100 (4%), thus totaling 25/100 VTEs (25%). Of the 21 PEs, 3 of 21 (14%) involved subsegmental, 15 of 21 (71%) segmental, 1 of 21 (5%) lobar, and 2 of 21 (10%) central pulmonary arteries. Of the 12 DVTs, all were distal (below the popliteal vein), and 2 of 12 (17%) were also proximal; 5 of 12 (42%) were unilateral, of which 3 of 5 (60%) on the contralateral saphenous vein-harvested leg. No VTE caused hemodynamic instability, and none was clinically suspected. In conclusion, VTEs were frequent, some extensive proximal VTEs occurred, but most were distally localized. Many patients in this series would have been discharged without diagnosis of and treatment for PE and/or DVT.

Pulmonary Complications After Cardiac Surgery

Over the past two decades there has been a steady evolution in the practice of adult cardiac surgery with the introduction of “off-pump” surgery. However, respiratory complications remain a leading cause of postcardiac surgical morbidity and can prolong hospital stays and increase costs. The high incidence of pulmonary complications is in part due to the disruption of normal ventilatory function that is inherent to surgery in the thoracic region. Furthermore, patients undergoing such surgery often have underlying illnesses such as intrinsic lung disease (e.g., chronic obstructive pulmonary disease) and pulmonary dysfunction secondary to cardiac disease (e.g., congestive heart failure) that increase their susceptibility to postoperative respiratory problems. Given that many patients undergoing cardiac surgery are thus susceptiple to pulmonary complications, it is remarkable that more patients do not suffer from them during and after cardiac surgery. This is to a large degree because of advances in anesthetic, surgical and critical care that, for example, have reduced the physiological insults of surgery (e.g., better myocardial preservation techniques) and streamlined care in the immediate postoperative period (e.g., early extubation). Moreover, the development of minimally invasive surgery and nonbypass techniques are further evidence of the attempts at reducing the homeostatic disruptions of cardiac surgery. This review examines the available information on the incidences, consequences, and treatments of postcardiac surgery respiratory complications.

Thrombelastographic changes in OPCAB surgical patients

The purpose of this study was to determine whether thrombelastography could detect hypercoagulability in the off-pump coronary artery bypass (OPCAB) patient. Seventeen OPCAB and six cardiopulmonary bypass (CPB) patients were studied pre- and postprocedure, as well as on each of the first three postoperative days (POD). In the OPCAB patients, there was a small reduction in the postprocedure coagulation index (CI). This was followed by an increase in the CI on each of the next three POD, reaching a level exceeding the mean preprocedure CI by 2.32 units, indicative of a state of relative hyper- coagulability. The mean CI for the CPB patients decreased significantly in the postprocedure sample. Over the next 72 h, the CI increased to a level that nearly equaled the preprocedure ‘baseline’. We concluded that our study identified a state of relative hypercoagulability in the OPCAB patient 72 h after surgery. The mechanism of this hypercoagulation, as well as the clinical significance of this finding, is yet to be determined.

Comparing the impact of supine and leg elevation positions during coronary artery bypass graft on deep vein thrombosis occurrence: a randomized clinical trial study

Deep vein thrombosis (DVT) is a common preoperative complication that occurs in patients who undergoing coronary artery bypass grafting surgery (CABG). Early ambulation, elastic stockings, intermittent pneumatic compression, and leg elevation, before and after surgery, are among preventative interventions. The goal of the study was to compare the effect of supine position with that of leg elevation on the occurrence of DVT during CABG and after, until ambulation. Between October, 2008, and May, 2011, a total of 185 eligible CABG patients admitted to the Cardiac Surgery Unit were randomly assigned to groups designated as the supine group (n = 92) or the leg-elevation group (n = 93). Of this total, 92 patients were assigned to the supine group and 93 to the leg-elevation group. Doppler ultrasonography of the superficial and deep veins in the lower extremities was performed for each patient before and after surgery. Logistic regression analysis was conducted to investigate the possible independent factors associated with DVT. DVT was detected in 25 (13.5%) patients: 17 (18.4%) patients in the supine position group and 8 (8.6%) in the leg-elevation group (P value = .065). After adjustment for confounding factors there was no effect of position on the presence of DVT (P = .126).Clots were often localized in legs ipsilateral to the saphenous vein harvest. The authors conclude that a positive, albeit not statistically significant, trend was evident toward higher incidence of silent DVT in supine position during and after CABG in comparison with leg elevation. Future studies with larger sample sizes are required to confirm this result.

Comparative effectiveness of preventative therapy for venous thromboembolism after coronary artery bypass graft surgery

BACKGROUND

Controversy exists regarding the optimal preventative therapy for venous thromboembolism (VTE) after coronary artery bypass graft (CABG) surgery. We sought to compare the effectiveness and safety of the most commonly used regimens.

METHODS AND RESULTS

We assembled a cohort of 92 699 patients who underwent CABG between 2004 and 2008, using the Premier database. Patients were categorized by method of VTE prevention initiated within 48 hours of surgery, including no preventative therapy (n=55 400), mechanical preventative therapy (n=21 162), subcutaneous unfractio--nated or low-molecular-weight heparin (n=10 718), subcutaneous fondaparinux (n=88), and concurrent mechanical-chemical therapy (n=5331). The incidence of VTE and major bleeding events within 6 weeks of CABG were compared, using multivariable and propensity score adjustment. The overall incidence of VTE for the entire cohort was 0.74%, and the incidence of major bleeding was 1.43%. VTE and bleeding events occurred with similar incidence in each of the patient categories (VTE: 0.70%, 0.79%, 0.81%, 1.14%, and 0.73%; major bleeding: 1.36%, 1.45%, 1.69%, 3.41%, 1.50%; no prevention, mechanical prevention, subcutaneous heparin, subcutaneous fondaparinux, concurrent mechanical-chemical prevention, respectively). Compared with receiving no prevention, the use of mechanical prevention or subcutaneous heparin did not significantly reduce the risk of VTE or change the risk of major bleeding (P=NS).

CONCLUSION

Venous thromboembolism occurs infrequently after CABG. Compared with the use of no prevention, the administration of chemical or mechanical preventative therapies to CABG patients does not appreciably lower the risk of VTE. These data provide support for the common practice of administering no VTE preventative therapy after CABG, used for nearly 60% of patients within this cohort.

Pulmonary embolism following coronary artery bypass grafting

BACKGROUND

Pulmonary embolism (PE) is a life-threatening complication, with a deceptive clinical presentation following coronary artery bypass grafting (CABG).

METHODS

We identified 13 studies on PE in post-CABG patients, spanning a period of 34 years.

RESULTS

The overall cumulative incidence of PE following CABG was 1.3% (111 PEs in 8553 CABGs).

CONCLUSION

We suggest further prospective randomized studies to examine the effect of saphenous system vein grafting, and choice of low molecular weight heparin prophylaxis on the incidence of post-CABG PE.

Deep venous thrombosis of the neck and pulmonary embolism in patients with a central venous catheter admitted to cardiac rehabilitation after cardiac surgery: a prospective study of 815 patients

Central venous catheters (CVCs) are widely used for therapeutic purposes and to measure hemodynamic variables that cannot be recorded from a peripheral vein. However, the method can involve complications. In cardiac surgery, CVCs are electively placed in the right internal jugular vein but there is little information on deep venous thrombosis (DVT) in catheterized veins (CVC-related DVT) or on secondary pulmonary embolism (PE). The impact of CVC-related DVT and PE in cardiac surgery and measures to prevent PE were assessed. We used ultrasonography (US) to check the point of insertion of CVC in 815 patients in the intensive cardiac rehabilitation unit after heart surgery. In this series, 386 patients (48%) had CVC-related DVT; those already receiving anticoagulant, and considered at low risk, continued that therapy, while those taking an antiplatelet agent (aspirin 100 mg daily) but deemed at high risk of PE from the US findings were given an anticoagulant instead. Only patients with CVC-related DVT at low risk of PE continued taking aspirin. At 3 months, there were no cases of PE among patients receiving an anticoagulant, but six on antiplatelet had non-fatal PE. The prevalence of PE in the whole series of 815 patients was 0.7%. CVC-related DVT is a frequent complication of heart surgery. Anticoagulant therapy started early does not prevent thrombus formation but probably prevents PE, whereas antiplatelet gives no such protection. Sonographic screening of the CVC removal in intensive care unit may be useful for avoiding PE after CVC-related DVT.

Analysis of bedside entertainment services' effect on post cardiac surgery physical activity: a prospective, randomised clinical trial

BACKGROUND

A rising number of acute hospitals in the UK have been providing patients with bedside entertainment services (BES) since 1995. However, their effect on postoperative patient mobility has not been explored.

OBJECTIVES

The aim of this prospective randomised clinical trial was to compare the level of postoperative physical activity and length of in-hospital stay of patients undergoing cardiac surgery depending on whether they had access to BES or not.

METHODS

One hundred patients requiring elective cardiac surgery were randomised to receive access to BES (52 patients) or not (48 patients). Pedometers were used to quantify postoperative physical activity for 5 days. To assess the significance of the effect of intervention (TV off or on) on the pedometer counts over time a mixed effect Poisson regression model is used, with the time varying aspect as random component. The potential influence of gender difference and age on pedometer counts were assessed by incorporating these two factors as covariates in the Poisson model.

RESULTS

On average, patients with no access to BES walked more than those with BES access. This difference ranged between 192 and 609 steps in favour of the first group for each individual postoperative day. Patients with no access to BES were 84% more likely (risk ratio: 1.84, 95% CI: 1.29-2.63) to walk higher number of steps than patients with access to BES. On average, participants with access to BES were likely to stay longer in hospital (median of 7 days with interquartile range 6-7 days), than participants with no access to BES (median of 6 days with interquartile range 5-7 days), however the difference did not reach statistical significance.

CONCLUSION

We have demonstrated that the bedside entertainment systems may have an adverse effect on post cardiac surgery patient ambulation and may contribute to an increase in hospital stay.

Acute kidney injury and chronic kidney disease after cardiac surgery

Kidney dysfunction is common after cardiac surgery and predicts mortality risk and poorer long-term outcome, particularly when acute injury superimposes upon chronic kidney disease. Numerous insults contribute to perioperative renal impairment including major surgical trespass, procedure-specific interventions (eg, deep hypothermic circulatory arrest), and postoperative complications. Regardless of cause, evidence supports a role for renal impairment and accumulation of "uremic toxins" as direct contributors to adverse outcome. No one has yet characterized a loss of renal function small enough to be insignificant. Despite considerable research focus, progress in development of interventions aimed at perioperative renoprotection has been disappointing. However, practice modifications can influence the likelihood of acute kidney injury, and several recent advances provide hope for the future. We review pathophysiologic understanding of this disorder; evaluate the confusing relationship (causal v epiphenomena) among acute kidney injury, chronic kidney disease, and adverse outcome after cardiac surgery; and provide an evidence-based assessment of the conduct of cardiac surgery and renoprotection strategies.

Acute Pulmonary Thromboembolism During Mitral Valve Repair

Perioperative pulmonary thromboembolism during cardiac surgery is extremely rare. We report a 55-year-old male, who developed acute pulmonary thromboembolism during mitral valve repair. Intra-operative trans oesophageal echocardiography failed to demonstrate thromboembolus in the pulmonary arteries but it showed the secondary signs of acute pulmonary artery obstruction. Thromboembolectomy was done after high index of suspicion on clinical grounds was found and the patient recovered. The diagnostic accuracy and sensitivity of transoesophageal echocardiography in circumstances with altered haemodynamics is questionable and has not been investigated. Therefore, indirect evidence of pulmonary artery obstruction on echocardiography may have a predictive value and failure to demonstrate pulmonary thromboembolism by this tool should not exclude the possibility of it especially when it is highly suspected.

Guideline on antiplatelet and anticoagulation management in cardiac surgery

This document presents a professional view of evidence-based recommendations around the issues of antiplatelet and anticoagulation management in cardiac surgery. It was prepared by the Audit and Guidelines Committee of the European Association for Cardio-Thoracic Surgery (EACTS). We review the following topics: evidence for aspirin, clopidogrel and warfarin cessation prior to cardiac surgery; perioperative interventions to reduce bleeding including the use of aprotinin and tranexamic acid; the use of thromboelastography to guide blood product usage; protamine reversal of heparin; the use of factor VIIa to control severe bleeding; anticoagulation after mechanical, tissue valve replacement and mitral valve repair; the use of antiplatelets and clopidogrel after cardiac surgery to improve graft patency and reduce thromboembolic complications and thromboprophylaxis in the postoperative period. This guideline is subject to continuous informal review, and when new evidence becomes available. The formal review date will be at 5 years from publication (September 2013).

Multidetector CT and coronary artery bypass grafts

The aim of this review is to provide--starting from anatomical, surgical and pathophysiological data--elements for evaluating the status of coronary artery bypass grafts with multidetector computed tomography (CT), taking into consideration the most common conduits used (left and right internal mammary arteries, saphenous vein, radial artery, gastroepiploic artery) and early and late complications (stenosis or obstruction, vasospasm, aneurysms and pseudoaneurysms, malposition). Some of the major problems regarding the examination technique and image analysis are also discussed. Finally, we offer general guidelines for reporting the examination results.

Autopsy findings in patients on postcardiotomy extracorporeal membrane oxygenation (ECMO)

OBJECTIVES

To assess the clinical sensitivity of causes of death, concomitant diseases and postoperative complications including thromboembolic events in ECMO patients.

METHODS

Between January 2000 and December 2004 154/202 patients (76.2%) died after postcardiotomy ECMO circulatory support. Autopsy was performed in 78 (50.6%) consecutive patients. Clinical and post-mortem data were prospectively recorded and compared concerning causes of death and postoperative complications including venous and arterial thromboembolisms and significant comorbidities.

RESULTS

Mean age was 62.1+/-11.3 years, ejection fraction was 43.4+/-17.3%. 39.7% were emergency operations including acute coronary syndrome in 25.6% and preoperative cardiogenic shock in 28.2%. Successful ECMO weaning rate was 43.6%. Mean postoperative survival was 11.3 days. Premortem unknown concomitant diseases were found in 63 patients (80.8%) with clinical relevance in 9 patients (11.5%). Clinically unrecognized postoperative complications were found in 59 patients (75.6%) including acute cerebral infarction (n=7), acute bowel ischemia (1), intestinal perforation (3), pneumonia (4), venous thrombus formation (25) and systemic thromboembolic events (24). Clinically based causes of death were cardiac in 62.8%, multi-organ failure in 10.3%, cerebral in 5.1%, respiratory in 10.3%, fatal pulmonary embolism in 2.6%, technical in 5.1%, and others in 3.8%. Unexpected causes of death were found by autopsy in 22 patients (28.2%) including myocardial infarction (n=5), acute heart failure (4), fatal pulmonary embolism (2), pneumonia (2), ARDS (1), lung bleeding (1), fatal cerebrovascular event (4) and multiorgan failure (3).

CONCLUSIONS

In ECMO patients major discrepancies between clinical and post-mortem examination were found. The true incidence of thromboembolic events is highly underestimated by clinical evaluation.

Massive pulmonary embolism after off-pump coronary artery bypass surgery

An 88-year-old woman developed an acute massive pulmonary embolism after off-pump coronary artery bypass surgery. She experienced dyspnea while walking on the sixth day after operation. Her chest radiograph showed pleural effusion. Initially, she was treated for heart failure due to bypass graft occlusion. A repeat echocardiogram revealed enlargement of the right ventricle. Multislice computed tomography showed a massive embolus in the pulmonary artery. Surgical embolectomy was performed, and her postoperative course was easy. Recently, the incidence of pulmonary embolism in Japanese people has been rising. In addition, widespread implementation of off-pump coronary artery bypass compromises the protective effect against pulmonary embolus after cardiac surgery. Although the incidence of pulmonary embolism after coronary artery bypass surgery is still low in Japan in comparison to that in Western countries, prophylaxis against pulmonary embolism after off-pump coronary artery surgery is becoming more important.

Bivalirudin: Pharmacology and Clinical Applications

Bivalirudin (Hirulog, Angiomax) is a specific, reversible and direct thrombin inhibitor with a predictable anticoagulant effect. It is cleared by both proteolytic cleavage and renal mechanisms, predominantly glomerular filtration. Bivalirudin inhibits both circulating thrombin and fibrin bound thrombin directly by binding to thrombin catalytic site and anion-binding exosite I in a concentration-dependent manner. Bivalirudin prolongs activated partial thromboplastin time, prothrombin time, thrombin time and activated clotting time (ACT). ACT levels with bivalirudin do not correlate with its clinical efficacy. Bivalirudin with a provisional GpIIb/IIIa inhibitor is indicated in elective contemporary percutaneous coronary intervention (PCI). In respect to combined ischemic and hemorrhagic endpoints of death, myocardial infarction, unplanned urgent revascularization and major bleeding during PCI (including subgroups of patients with renal impairment and diabetes) bivalirudin is not inferior to unfractioned heparin and planned GpIIb/IIIa inhibitors. In addition, bivalirudin has been consistently shown to have significantly less in-hospital major bleeding than heparin alone or heparin in combination with a GpIIb/IIIa inhibitor. Bivalirudin appears to be also safe and effective during PCI in patients with heparin-induced thrombocytopenia. Finally, data from PCI studies support the safety and efficacy of bivalirudin, although its direct randomized comparison with unfractionated heparin is lacking.

[Prevention of venous thromboembolism following cardiac, vascular or thoracic surgery]

In the absence of thromboprophylaxis, coronary artery bypass graft surgery (CABG), intrathoracic surgery (thoracotomy or video-assisted thoracoscopy), abdominal aortic surgery and infrainguinal vascular surgery are high-risk surgeries for the development of venous thromboembolic events (VTE). The incidence of VTE following surgery of the intrathoracic aorta, carotid endarterectomy or mediastinoscopy is unknown. Data from the litterature are lacking to draw evidence-based recommandations for venous thromboprophylaxis after these three types of surgeries, and the following guidelines are but experts'opinions (Grade D recommendations). Thromboprophylaxis is recommended after CABG (Grade D), with either subcutaneous (SC) low molecular weight heparin (LMWH) or SC or intravenous (i.v.) unfractioned heparin (UH) (PTT target = 1.1-1.5 time control value) (both grade D). This may be combined with the use of intermittent pneumatic compression device (Grade B). After valve surgery. The anticoagulation recommended to prevent valve thrombosis is sufficient in order to prevent VTE. We recommend thromboprophylaxis with either LMWH or low dose UH to prevent VTE after aortic or lower limbs infrainguinal vascular surgery (both grade B and D). Vitamine K antagonists (VKA) are not recommended in this indication (Grade D). We recommend thromprophylaxis following intrathoracic surgery via thoracotomy or videoassisted thoracoscopy (grade C). Either subcutaneous LMWH or subcutaneous or i.v. low dose UH may be used (Grade C). Efficacy of intermittent pneumatic compression device has been demonstrated in a study (grade C). VKA are not recommended (grade D). No further recommendation regarding the duration of thromboprophylaxis after these three types of surgeries can be made.

Coronary Artery Bypass Grafts: Assessment with Multidetector CT in the Early and Late Postoperative Settings

Coronary artery bypass graft (CABG) surgery is the standard of care in the treatment of advanced coronary artery disease. It is well known that the long-term clinical outcome after myocardial revascularization depends on the patency of the bypass grafts. In the past, invasive coronary angiography was used to assess the status of the grafts and check for graft occlusion. Recently, computed tomography (CT), particularly multidetector CT with electrocardiographic gating, has emerged as an important diagnostic tool for evaluation of CABGs in both the early (< or =1 month) and late (>1 month) postoperative settings. A variety of postoperative complications may manifest as dyspnea and chest pain, thereby mimicking recurrent angina secondary to graft occlusion. Owing to its improved spatial resolution compared with that of earlier-generation CT scanners and its ability to produce three-dimensional and multiplanar images, multidetector CT has assumed an integral role in characterization of graft patency while allowing investigation of alternative postoperative complications. In addition, the expanded capabilities of volumetric imaging may provide valuable information in preoperative planning for repeat CABG surgery.

Significant value of autopsy for quality management in cardiac surgery

OBJECTIVE

With recent advances in diagnostic imaging, the value of autopsy has been called into question. The aim of our study was to assess the current impact of autopsy for early postoperative quality management in cardiac surgery.

METHODS

Between 2000 and 2003, a total of 14,313 patients underwent cardiac surgery at our center. Of these, 898 patients (6.3%) died, and autopsy was performed in 468 cases (52.1%). Data from clinical and postmortem examination were prospectively analyzed regarding causes of death, postoperative complications, concomitant diseases, and surgery-associated pathologic findings.

RESULTS

Mean age was 68.7 years. Mean survival was 13.9 postoperative days. On autopsy, causes of death were cardiac in 49.8% of cases (n = 233), respiratory in 8.3% (n = 39), cerebral in 6.4% (n = 30), abdominal in 4.7% (n = 22), multiorgan failure or sepsis in 14.9% (n = 70), pulmonary embolism in 6.6% (n = 31), procedure associated in 8.3% (n = 39), and others in 0.9% (n = 4). Discrepancies between clinical and postmortem determinations of cause of death were found in 108 cases (23.1%). These were acute myocardial infarction (n = 38), low cardiac output (n = 9), respiratory (n = 8), cerebral (n = 5), abdominal (n = 7), multiorgan failure or sepsis (n = 12), pulmonary embolism (n = 18), and procedure associated (11). Clinically unrecognized postoperative complications were found in 364 cases (77.8%). Unknown concomitant diseases were found in 464 cases (99.1%), with potential therapeutic relevance in 90 cases (19.2%). In 85 cases (18.2%), autopsy examination revealed 96 premortem unrecognized surgery-associated pathologic findings.

CONCLUSION

A high overall discrepancy rate between premortem and autopsy diagnoses was recognized. Autopsy revealed clinically relevant information in a significant number of cases. Therefore autopsy remains essential for quality assessment in perioperative treatment.

Effects of ankle exercise combined with deep breathing on blood flow velocity in the femoral vein

Ankle exercises are commonly used to facilitate venous return in the lower extremity and to prevent deep vein thrombosis. Moreover, the respiratory cycle affects venous return. This study examined the effects of ankle exercise combined with deep breathing on the blood flow velocity in the femoral vein. Twenty healthy males (mean age 21.3 years), who had no medical history of lower extremity disease, were recruited for this study. The blood flow velocity in the femoral vein was measured while performing four exercise protocols: quiet breathing while resting (QR), deep breathing (DB), ankle exercise with quiet breathing (AQB), and ankle exercising combined with deep breathing (ADB). Using a Doppler ultrasound with an 8 MHz probe, peak blood flow velocities were collected for a 20 second period at the start of the inspiration phase in each protocol, three times. There were statistically significant differences in the peak blood flow velocity in the femoral vein with the four protocols (p lt 0.001). The mean (SD) peak blood flow velocity in the femoral vein was as follows: QR 10.1 (4.2) cm/sec, DB 15.5 (3.9) cm/sec, AQB 20.7 (6.6) cm/sec, and ADB 26.5 (9.4) cm/sec. Post hoc analyses revealed significant differences between each of the four protocols (p(adj) lt 0.01). The mean peak blood flow velocity in the femoral vein was greatest with the ADB protocol, which implies that the ADB protocol may be useful to prevent the blood stasis in patients at risk of deep vein thrombosis.

Deep Vein Thrombosis Among Patients Entering Cardiac Rehabilitation After Coronary Artery Bypass Surgery

BACKGROUND

Little information is available about the prevalence of deep vein thrombosis (DVT) after discharge from cardiac surgery units and its impact on rehabilitation programs.

OBJECTIVES

To estimate the rate of DVT, in relation to different thromboprophylaxis strategies, in patients with a recent coronary artery bypass graft (CABG) entering cardiac rehabilitation.

METHODS

Two hundred seventy consecutive patients admitted to three rehabilitation facilities after CABG surgery from 19 cardiac surgery units (male patients, 81%; mean +/- SD age, 64 +/- 9 years; interval after operation, 4 to 19 days) underwent serial leg venous ultrasound examination on admission to three rehabilitative units.

RESULTS

At admission, antiplatelet treatment was present in all patients except 10 with absolute contraindications. In 171 patients (63%), heparin prophylaxis (low-molecular-weight heparin once daily, 87%; unfractionated heparin twice daily, 13%) was reported, limited to the early postoperative period (< or = 3 days) in 102 patients (38%). DVT was detected in 47 patients (17.4%). The rate of proximal and isolated distal DVT was 2.6% (7 cases) and 14.8% (40 cases), respectively. DVT was complicated in two cases (0.7%) by symptomatic pulmonary embolism, fatal in one case (0.4%). Clots were found in the leg contralateral to the saphenous vein harvest site in half of all DVT cases. Forty-three DVT cases (91%) were diagnosed at admission, while serial ultrasound testing allowed diagnosis of an additional 4 distal DVT cases. At multivariate analysis, female sex (p < 0.001) and length of stay in the surgery unit > 8 days (p < 0.05) were independently associated with risk of DVT in the rehabilitation setting. The adoption of heparin prophylaxis until discharge predicted the absence of DVT after adjustment for immobility (p < 0.05).

CONCLUSIONS

This study showed a high rate of DVT in patients entering cardiac rehabilitation after CABG surgery. Wearing unilateral graded compression stockings after CABG surgery had limited efficacy, as clots were often localized in legs contralateral to the saphenous vein harvest site.

Impending paradoxical embolism after coronary artery bypass grafting successful surgical treatment

We describe a case of impending paradoxical embolism of a 22 cm long thromboembolus, straddling over a patent foramen ovale, detected by transthoracic and transesophageal echo 11 days after a coronary artery bypass operation. The patient underwent successful emergency removal of the clot and closure of the patent foramen ovale. A vena cava filter was placed because of new thrombi detected in deep veins of the legs.

Serious adverse vascular events associated with perioperative interruption of antiplatelet and anticoagulant therapy

BACKGROUND

Antithrombotic medications may increase perioperative bleeding during cutaneous surgery. Whether to discontinue these medications before surgery is controversial.

OBJECTIVE

To evaluate the available evidence in order to generate preliminary guidelines regarding the perioperative use of antithrombotics.

METHODS

Presentation of two cases of adverse events after preoperative discontinuation of antithrombotics, review of current anticoagulant and antiplatelet drugs, and review of the literature concerning perioperative antithrombotics in cutaneous surgery.

RESULTS

Perioperative withholding of antithrombotics in cutaneous surgery may be associated with serious adverse vascular events. Continuing antithrombotics in these circumstances does not appear to significantly increase bleeding complications. The complexity of available antithrombotics makes case-by-case determinations regarding their use difficult.

CONCLUSION

Cutaneous surgeons should strongly consider perioperative continuation of patients' antithrombotic drugs. The final determination should be made by the surgeon after evaluation of the circumstances and, if necessary, consultation with other experts.

A prospective, randomized comparison of thromboelastographic coagulation profile in patients receiving lactated Ringer's solution, 6% hetastarch in a balanced-saline vehicle, or 6% hetastarch in saline during major surgery

OBJECTIVES

To compare the effects of lactated Ringer's solution (LR), 6% hetastarch in a balanced-saline vehicle (HS-BS), and 6% hetastarch in normal saline (HS-NS) on coagulation using thromboelastography.

DESIGN

Prospective, randomized double-blinded evaluation of previously published clinical trial.

SETTING

Tertiary-care medical center.

PARTICIPANTS

Patients undergoing elective noncardiac surgery with an anticipated blood loss >500 mL. A total of 90 patients were enrolled with 30 patients in each group.

INTERVENTIONS

Patients received a standardized anesthetic. LR, HS-BS, and HS-NS were administered intraoperatively based on a fluid administration algorithm. Hemodynamic targets included maintenance of arterial blood pressure, heart rate, and urine output within a predefined range.

MEASUREMENTS AND MAIN RESULTS

Thromboelastography variables for r time, k time, maximum amplitude, and alpha angle (mean +/- SD) were recorded at induction of anesthesia, at the end of surgery, and 24 hours postoperatively. Patients in the LR group showed a state of hypercoagulation at the end of surgery with reductions (p < 0.005) in r time (-3.8 +/- 6.7 mm) and k time (-1.7 +/- 2.5 mm). This state of hypercoagulation continued into the postoperative period. Patients in the HS-NS group showed a state of hypocoagulation with increases (p < 0.05) in r time (+6.2 +/- 8.5 mm) and k time (+1.7 +/- 3.9 mm) and a reduction in maximum amplitude (-8.0 +/- 9.8 mm) at the end of surgery. This state of hypocoagulation was reduced in the postoperative period. Patients in the HS-BS group showed no significant changes in coagulation status at end of surgery, with the smallest changes in r time (-0.3 +/- 4.1 mm), k time (+0.1 +/- 3.1 mm), maximum amplitude (-5.4 +/- 12.3 mm), and alpha angle (0.3 +/- 12.5 degrees ).

CONCLUSION

LR-treated patients exhibited a hypercoagulative profile that persisted into the postoperative period. HS-BS administration was associated with a lesser change in the coagulation profile compared with HS-NS, which was associated with a hypocoagulative state.