Preoperative prediction of prolonged mechanical ventilation following coronary artery bypass grafting.

OBJECTIVE: Few studies have attempted to evaluate who would require prolonged mechanical ventilation following heart surgery. The objectives of this study were to identify predictors of prolonged ventilation in a large group of coronary artery bypass grafting (CABG) patients from a single institution. METHODS: One thousand, eight hundred and twenty-nine consecutive patients undergoing CABG were reviewed retrospectively and evaluated for preoperative predictors of prolonged ventilation which included: age, gender, ejection fraction (EF), renal function, diabetes, angina status, New York Heart Association Class, number of diseased vessels, urgency of the procedure, re-operation, chronic lung disease (COPD) and intraoperative variables such as IABP, inotropes, stroke and myocardial infarction. Prolonged ventilation was defined as > or = 24 h. Stepwise logistic regression analysis was performed. RESULTS: Patients were on average 65.4+/-10.6 years of age, 30% were diabetic, 80% had triple vessel disease and 93% were of functional class III/IV. The mean ejection fraction was 60+/-16 percent. Overall peri-operative mortality was 2.7%. There were 157 patients that required prolonged ventilation with a peri-operative mortality of 18.5% (P < 0.001). Preoperative independent predictors of prolonged ventilation were found to be: unstable angina (OR 5.6), EF < 50 (OR 2.3), COPD (OR 2.0), preop. renal failure (OR 1.9), female gender (OR 1.8) and age > 70 (OR 1.7). Based on these predictors, a model was created to estimate of the risk of prolonged ventilation in individual patients following CABG with results ranging from < or = 3% in patients without any risk factors to > or = 32% in patients with five or more independent risk factors.Certain intraoperative variables were strong predictors of prolonged ventilation and included: stroke (OR 12.3), re-operation for bleeding (OR 6.9) and perioperative MI (OR 5.8). CONCLUSION: We were able to create a stable model where several preoperative and intra-operative variables were shown to be predictive of prolonged ventilation after CABG surgery. The ability to identify patients at increased risk for prolonged ventilation may allow the development of pre-emptive strategies and more effective resource allocation.     

Predictors and outcomes of prolonged ventilation after coronary artery bypass graft surgery

This study investigated and compared the risk factors and outcomes of patients undergoing coronary artery bypass graft surgery with and without the occurrence of prolonged mechanical ventilation. Data in a cardiac surgery database were examined retrospectively. Data selected included any isolated coronary artery bypass graft surgery performed by the surgical group from August 2005 to June 2009. The resulting cohort included a total of 2933 patients which was comprised of 116 patients with a ventilation time of greater than 72 hours (prolonged ventilation) and 2817 patients with a ventilation time of 72 hours or less (no prolonged ventilation). Patients with a prolonged ventilation time were matched (1:3 ratio) to patients not requiring a prolonged ventilation time by year of surgery resulting in our study cohort of 464 patients. To generate the unadjusted risks of each factor, χ(2) and t test analysis were performed. Logistic regression analysis was then used to investigate the adjusted risk between cases and controls and each of the significant variables. χ(2) and t tests were conducted comparing cases and controls with the outcome variables. Patients undergoing coronary artery bypass graft that experienced a prolonged ventilation time (cases) were more likely female, had a New York Hospital Association functional class of III or IV, and had a longer perfusion time. There was no significant difference between cases and controls with diabetes, chronic obstructive pulmonary disease, left ventricular ejection fraction, or body mass index while controlling for all significant risk factors. Careful patient selection and preparation during preoperative evaluation may help identify patients at risk for prolonged mechanical ventilation and thus help prevent the added morbidity and mortality associated with it.     

Predictors of atrial fibrillation after off-pump coronary artery bypass graft surgery

Background: Postoperative atrial fibrillation (AF) is one of the most commoncomplications after cardiothoracic surgery and is associatedwith an increased risk of stroke, and longer hospital stay.The pathophysiology of postoperative AF is uncertain, and itsprevention remains unsatisfactory. Many previous studies haveexamined the predictors of AF after on-pump coronary arterybypass graft surgery (CABG), but there are few reports afteroff-pump CABG. Methods: The aim of the present prospective observational study, in which296 consecutive patients were enrolled, was to elucidate thepredictors of AF after off-pump CABG. The association of perioperativefactors with AF was investigated using univariate analysis.Significant variables were included into a stepwise logisticregression model to ascertain their independent influence onthe occurrence of AF. Results: The incidence of AF was 32%. AF prolonged the time until patientswere fit for discharge by 3 days (P < 0.01). Stepwise multivariateanalysis identified increasing age [odds ratio (OR) 1.44 per10-yr increase; 95% confidence interval (CI) 1.06–1.95],intraoperative average core temperature (OR 1.64; 95% CI 1.05–2.56),the average cardiac index in the intensive care unit (OR 0.37;95% CI 0.19–0.71), and intraoperative fluid balance (OR0.96 per 100-ml increase; 95% CI 0.93–0.99) as independentpredictors of postoperative AF. Conclusion: Our present findings indicate that ageing, the intraoperativefluid balance, and postoperative cardiac index are associatedwith the onset of AF after off-pump CABG.     

Predictors of atrial fibrillation after off-pump coronary artery bypass graft surgery

OBJECTIVE: Atrial fibrillation is the most common complication after coronary artery bypass graft surgery. This arrhythmia may lead to hemodynamic compromise, prolonged hospitalization, and increased risk for cerebral thromboembolism. Older age is the only variable consistently associated with the development of postoperative atrial fibrillation; however, no strong predictive model exists. The purpose of this study was to identify perioperative characteristics associated with new-onset atrial fibrillation in patients undergoing off-pump coronary artery bypass grafting. DESIGN: Prospective, observational. SETTING: University tertiary care hospital. PARTICIPANTS: One hundred sixty consecutive patients undergoing off-pump coronary artery bypass grafting. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Incidence of postoperative atrial fibrillation was the major outcome. Atrial fibrillation occurred in 33 patients (20.6%). Multivariate analysis identified reintervention (odds ratio 26.8), revascularization of the ramus medianus (odds ratio 3.9), and age (odds ratio 1.069 per year) as the only independent predictors of postoperative atrial fibrillation. All patients were in sinus rhythm at hospital discharge. One hospital death was noted. CONCLUSIONS: Despite the less invasive approach, the incidence of postoperative atrial fibrillation is high after off-pump coronary artery bypass grafting. Older age, grafting of the ramus medianus, and a redo operation were predictors of new-onset postoperative atrial fibrillation. It is possible that left atrial stretching with heart dislocation during revascularization of the lateral wall could lead to postoperative atrial fibrillation.     

Postoperative hyperthermia following off-pump versus on-pump coronary artery bypass surgery

OBJECTIVE: Hyperthermia is common in the first 24 hours following coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CPB). An inflammatory response to CPB is often implicated in the pathophysiology of this fever. Unlike CABG with CPB, the temperature pattern after off-pump CABG (OPCAB), where CPB is avoided, has not yet been described. The purpose of this study was to describe the postoperative temperature pattern following OPCAB and to compare it with that following on-pump cardiac surgery. DESIGN: Retrospective, observational study. SETTING: Tertiary care university hospital. PARTICIPANTS: Consenting patients undergoing CABG or OPCAB procedures. INTERVENTIONS: Observational. MEASUREMENTS AND MAIN RESULTS: Of the CABG patients, 89% had temperature elevations above 38 degrees C, versus 44% of the OPCAB patients (P = 0.04). Peak body temperature was higher in the on-pump patients (CABG 38.5 degrees C +/- 0.4 degrees C versus OPCAB 37.9 degrees C +/- 0.5 degrees C; P = 0.002), as was the area under the curve for temperatures greater than 38 degrees C (CABG 1.6 +/- 1.7 degrees C/hr versus OPCAB 0.4 +/- 1.2 degrees C/hr; P = 0.02). CONCLUSIONS: Off-pump CABG surgery patients experience less hyperthermia compared with on-pump CABG patients. The reasons for a lower incidence and severity of hyperthermia after OPCAB surgery are not known, but may be related to a reduced inflammatory response.     

Management of porcelain aorta and calcified great vessels in coronary artery bypass grafting with off-pump and no-touch technology

A 69-year-old woman presented with postinfarct unstable angina and decreased ventricular function secondary to significant left main coronary artery stenosis in combination with total right coronary artery occlusion. We did successful off-pump coronary revascularization in this patient with severely calcified ascending aorta and great vessels, subtotal aortobiiliac stenoses, a history of previous stroke, and right carotid endarterectomy.     

Right coronary artery spasms triggered by mechanical compression during off-pump coronary artery bypass grafting surgery

In this case report, we describe recurrent spasms of the right coronary artery with no apparent preexisting abnormal angiogram that caused second-degree atrioventricular (AV) block and inferior wall hypokinesis. These hemodynamic changes were induced by mechanical compression of the right coronary artery by a pericardium drain tube. From our experience, we should be aware that mechanical compression may trigger an exaggerated vasomotor response, leading to severe coronary artery spasms.     

Pseudoaneurysms of the ascending aorta following coronary artery bypass surgery

BACKGROUND: Ascending aortic pseudoaneurysms following prior cardiac procedures are a rare entity. We reviewed our institutional experience given the isolated case reports in the literature. METHODS: A 10-year retrospective review identified 5 patients who underwent ascending aorta pseudoaneurysm repair. There were 3 women and 2 men with a median age of 70 years (range 63 to 79 years). Median duration from initial CABG to pseudoaneurysm repair was 5 years (range 5 months to 18 years). The clinical presentations included dyspnoea (2 patients), chest pain, fever of unknown origin, and a pulsatile mass. Four patients underwent urgent investigation and surgery. Diagnosis was established via CT scan (3 patients), transesophageal echocardiogram (1 patient), and MRA (1 patient). Two patients had a prior history of sternal wound infection. RESULTS: Mortality was 60%. One survivor experienced a stroke. The etiology was prior cannulation site in 4 cases and vein graft anastamotic site in 1. Necrotic aortic tissue was noticed in 2 cases. Aortic tissue cultures were negative in all the patients. Cardiopulmonary bypass was established prior to sternotomy in 4 cases and 1 case was performed off-pump. Inadvertent rupture of the pseudoaneurysm (without exsanguination) occurred in 2 cases following sternotomy. Repair was performed with bovine pericardial patch in 2 cases and plication in 3 cases. CONCLUSION: This highlights the varied presentation, necessity for urgent diagnosis and repair with a high operative mortality due to the late presentation. Aggressive diagnosis should be sought and consideration should be given to catheter-based interventions for initial treatment.     

Predictors of cognitive decline following coronary artery bypass graft surgery

BACKGROUND: A significant number of patients develop cognitive impairment that persists for months following coronary artery bypass grafting (CABG) surgery. Our objectives were to identify patient-related risk factors, processes of care, and the occurrence of any perioperative complications associated with cognitive decline. METHODS: Nine hundred thirty-nine patients enrolled in the Processes, Structures, and Outcomes of Care in Cardiac Surgery study undergoing CABG-only surgery at 14 Veterans Administration medical centers between 1992 and 1996 completed a short battery of cognitive tests at baseline and 6-months post-CABG. The composite cognitive score was based on the sum of errors for each individual item in the battery. Multiple linear regression analyses were used to identify independent predictors of the 6-month composite cognitive score. RESULTS: In multivariable analyses, patient characteristics associated with cognitive decline included cerebrovascular disease (p = 0.009), peripheral vascular disease (p = 0.007), history of chronic disabling neurologic illness (p = 0.016), and living alone (p = 0.049), while the number of years of education (p = 0.001) was inversely related to cognitive decline. After adjustment for baseline patient risk factors, the presence of any postoperative complication(s) (p = 0.001) was also associated with cognitive decline while cardiopulmonary bypass time (p = 0.008) was inversely related to cognitive decline. CONCLUSIONS: Patients with noncoronary manifestations of atherosclerosis, chronic disabling neurologic illness, or limited social support are at risk for cognitive decline after CABG surgery. In contrast, more years of education were associated with less cognitive decline. Preoperative assessment of risk factors identified in this study may be useful when counseling patients about the risk for cognitive decline following CABG surgery.     

Vasoplegic syndrome after off-pump coronary artery bypass surgery.

OBJECTIVE: The vasoplegic syndrome (VS) has been implicated in life-threatening complications after open heart surgery, where the whole-body inflammatory reaction is attributed to the cardiopulmonary bypass (CPB). Off-pump coronary artery bypass grafting (OPCAB) has been recently achieving growing enthusiasm mainly due avoiding the side effects of CPB. However herein the occurrence of VS in OPCAB is reported. METHODS: The vasoplegic syndrome usual findings occurring in the early postoperative period include severe hypotension, tachycardia, normal or elevated cardiac output and low systemic vascular resistance. Four patients underwent to OPCAB presented all the signs of VS intraoperatively or within the first 6 postoperative h. RESULTS: The patients needed aggressive vasoactive drug support for hemodynamic stabilization and all of them developed complications. These patients also had tendency to require administration of blood and blood derivatives due to diffuse and oozing type bleeding. Mean intensive care unit stay of surviving patients was 70 h and mean period of postoperative hospitalization was 9 days. Tumor necrosis factor-alpha blood levels in one patient were elevated postoperatively though no signs of infection were observed. One patient died. CONCLUSIONS: Although vasoplegic syndrome can complicate OPCAB surgery, the rationale for avoiding CPB remains valid considering the benefits provided by OPCAB.     

Current results of off-pump coronary artery bypass surgery

Whether to use or not use cardiopulmonary bypass-cardioplegic arrest to perform coronary artery bypass surgery is the main controversy presently facing our surgical specialty. The reported clinical outcomes are mainly retrospective and highly debatable for conclusiveness regarding the benefits of off-pump surgery. As more centers and larger patient cohorts are analyzed and reported, particularly over the last 2 years, off-pump surgery appears to provide significantly improved outcomes with decreased bleeding and transfusion requirements, less myocardial enzyme release, less ventilatory time, and decreased hospital stay and costs. Reported off-pump benefits for the major outcomes of operative mortality and stroke are encouraging, but less conclusive. From experienced centers, early off-pump angiographic graft patency has been comparable to previously published conventional results. High-risk, elderly patients may benefit the greatest from off-pump surgery. Although in relative technical infancy, off-pump coronary artery bypass grafting has demonstrated enough benefit outcomes that it is no longer an experimental procedure, but a valid surgical revascularization method requiring further investigation and continued usage.     

Multivessel off-pump coronary artery bypass surgery in the elderly.

OBJECTIVE: Coronary artery bypass grafting in the elderly patient is associated with increased perioperative morbidity and mortality. The avoidance of cardiopulmonary bypass (CPB) in this population is potentially beneficial. We examined our initial experience with off-pump multivessel coronary artery revascularization in patients aged 70 years and older. METHODS: In a consecutive series of 300 off-pump coronary artery bypass (OPCAB) operations performed by a single surgeon between 1996 and 1999, 98 patients were aged 70 years and older. These patients were compared with a consecutive cohort of 497 patients aged 70 years and older operated on with CPB in the same institution from 1995 to 1996, period where OPCAB surgery was not performed in our institution. RESULTS: Patients in the beating heart group were older (75+/-4 vs. 74+/-3 years; P=0.001). Gender distribution and other preoperative risk factors were comparable for the two groups. On average, 3.0+/-0.8 and 2.8+/-0.7 grafts per patient were completed in the OPCAB and the CPB groups, respectively (P=0.007). Perioperative mortality rates (OPCAB group, 3.1%; CPB group, 3.6%), perioperative myocardial infarction (OPCAB, 2.0%; CPB, 5.1%) and neurologic events (OPCAB, 1.0%; CPB, 3.2%) were comparable for the two groups. The incidence of postoperative atrial fibrillation was lower in the OPCAB group (42 vs. 54%; P=0.05). The need for allogenic blood transfusions was significantly less in the OPCAB group (53 vs. 82%; P=0.001). CONCLUSIONS: In patients aged 70 years and older, multivessel OPCAB surgery is associated with lower rates of postoperative atrial fibrillation and reduced transfusion requirements. Multivessel OPCAB in the elderly patient is an acceptable alternative to procedures performed with CPB.     

Retropericardial hematoma complicating off-pump coronary artery bypass surgery

We report the case of a retropericardial hematoma after triple-vessel off-pump coronary artery bypass grafting. Transesophageal echocardiography demonstrated a retropericardial hematoma that compressed the left atrium anteriorly and suppressed cardiac function. Injury to the pulmonary vein during placement of deep pericardial sutures and postoperative infusion of heparin were the likely causes of this rare but potentially fatal complication of an off-pump bypass operation.     

Anaesthesia for off-pump coronary artery bypass grafting surgery

Coronary artery bypass grafting (CABG) surgery may be undertaken with or without cardiopulmonary bypass (CPB) that is on- or off-pump. Although mortality and the incidences of coronary artery graft occlusion, myocardial infarction and stroke are equivalent, off-pump is associated with less blood loss, transfusion, requirement for inotropes, atrial fibrillation and chest infection compared with on-pump CABG surgery. Traditional high-dose opioid techniques of general anaesthesia should be avoided and either inhalation or total intravenous (IV) anaesthesia may be used. Meticulous monitoring, including electrocardiograph (ECG) and invasive arterial pressure measurement, is required. During grafting, good communication between anaesthetist and surgeon is essential. Maintenance of diastolic arterial pressure (DAP) is the key to preventing myocardial ischaemia and cardiovascular collapse. Surgical positioning for grafting to minimize hypotension is paramount and during grafting, IV fluid loading or vasoconstrictors and inotropes are effective treatments. Correction of bradycardia with atropine 0.3 mg IV or epicardial pacing also helps to maintain DAP. Persisting hypotension may require intra-aortic balloon pumping or conversion to on-pump CABG surgery. As there is less blood loss, there is a minimal requirement for cardiovascular support and early recovery of consciousness associated with off-pump compared with on-pump CABG surgery; patients in some institutions may be managed in a recovery room then transferred to a high-dependency unit, thus bypassing ICU.     

Anaesthesia for off-pump coronary artery bypass grafting surgery

Coronary artery bypass grafting (CABG) surgery may be undertaken with or without cardiopulmonary bypass (CPB), that is, on- or off-pump. Traditional high-dose opioid techniques of general anaesthesia should be avoided and either inhalation or total intravenous (IV) anaesthesia may be used. Meticulous monitoring, including electrocardiograph and invasive arterial pressure measurement, is required. During grafting, good communication between anaesthetist and surgeon is essential. Maintenance of diastolic arterial pressure (DAP) is the key to preventing myocardial ischaemia and cardiovascular collapse. Surgical positioning for grafting to minimize hypotension is paramount and during grafting, IV fluid loading or vasoconstrictors and inotropes are effective treatments. Correction of bradycardia with atropine 0.3 mg IV or epicardial pacing also helps to maintain DAP. Persisting hypotension may require intra-aortic balloon pumping or conversion to on-pump CABG surgery. As there is less blood loss, there is a minimal requirement for cardiovascular support and early recovery of consciousness associated with off-pump compared with on-pump CABG surgery; patients in some institutions may be managed in a recovery room then transferred to a high-dependency unit, thus bypassing the intensive care unit.     

Coronary endarterectomy with off-pump coronary artery bypass surgery

BACKGROUND: The aim of this study is to review our experience in coronary artery endarterectomy performed without cardiopulmonary bypass. METHODS: Between May 1998 and June 2000 off-pump coronary endarterectomy was performed on 11 patients who had unstable angina pectoris. The mean ejection fraction (EF) was 26.3 +/- 4.4, and all of the patients were New York Heart Association (NYHA) III or IV. Off-pump open left anterior descending (LAD) endarterectomy was performed on 7 patients, and closed endarterectomy of the right coronary artery (RCA) was done on the remaining 4. RESULTS: There were no deaths. None of the procedures was converted to on-pump operation; all the endarterectomies and bypasses were performed on the beating heart. All patients were completely revascularized, the left internal mammary artery was bypassed to the LAD in all operations, and all other grafts were of saphenous vein. At the end of the first year all bypasses to the endarterectomized arteries were patent. The overall patency rate was 95.6%. The mean postoperative EF was 34.7 +/- 9.1, which was significantly higher than the preoperative one (p < 0.05). At the end of the first year 9 patients were NYHA I or II and all were angina free in Canadian Cardiovascular Society class 0 or I. CONCLUSIONS: Endarterectomy without cardiopulmonary bypass can be performed in patients with severe left ventricular dysfunction who are expected to benefit from the complete revascularization.