Levent Guvendik

The impact of the duration of mechanical ventilation on the respiratory outcome in smokers undergoing cardiac surgery

STUDY OBJECTIVE To determine the impact of the duration of mechanical ventilation on the rate of pulmonary complications in smokers undergoing cardiac surgery. METHODS Retrospective analysis of 2163 patients who underwent elective cardiac surgery between September 1993 and August 1999. Based on a 3-month preoperative smoking cessation, patients were classified as smokers, ex-smokers and non-smokers. Their postoperative pulmonary complications were compared and related to the duration of mechanical ventilation. RESULTS Postoperative pulmonary complications were twice as common in smokers (29.5%) as non-smokers (13.6%) and ex-smokers (14.7%). Although smokers required a longer duration of mechanical ventilation, this was not statistically significant. Smokers had a higher rate of increase in postoperative pulmonary complications beyond 6 h of mechanical ventilation (P<0.002). CONCLUSION Prolonged mechanical ventilation in active smokers undergoing cardiac surgery is associated with a significant increase in the respiratory morbidity. Surgical strategies that allow early extubation may improve the respiratory outcome in smokers.

Management of a mediastinal cyst causing hyperparathyroidism and tracheal obstruction.

A 78-year-old man with a history of parathyroidectomy presented with hyperparathyroidism and tracheal obstruction. After excision of the mediastinal parathyroid cyst, his symptoms were completely relieved. The diagnosis, investigations, and management are discussed.

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 Fishers 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.

Changing operative characteristics of patients undergoing operations for coronary artery disease: impact on early outcomes.

BACKGROUND Aggressive nonsurgical revascularization results in high-risk patients presenting for operation at a later stage of coronary artery disease (CAD). This study investigated the effect of temporal changes in operative characteristics on outcomes of surgical revascularization. METHODS We compared preoperative, intraoperative, and postoperative variables of 5633 patients who underwent surgical revascularization for CAD between April 1998 and January 2007, divided into early (1998 to 2002, n = 2746) and late (2004 to 2007, n = 2887) eras. End points were major adverse outcomes (postoperative myocardial infarction, stroke, new dialysis) and operative mortality. RESULTS Median age (66 vs 68 years, p < 0.0001), prevalence of left ventricular systolic dysfunction, left main stem disease, prior angioplasty, diabetes mellitus, concomitant valve operation, and aprotinin use increased steadily over time. Severe symptoms, nonelective operations, mean number of grafts, postoperative bleeding, reopening for bleeding, and blood transfusion declined. Major complications were evenly distributed between the eras. Operative mortality for isolated coronary artery bypass grafting did not change (2.0% vs 1.8% p = 0.62) despite increasing operative risk (p < 0.0001); there was a 100% reduction in the absolute risk (110% to 210%) over time. The markers for operative difficulties, such as longer bypass times, were determinants of operative mortality and, in addition to other predictors like age and left ventricular systolic dysfunction, were more prevalent in the late era. CONCLUSIONS Coronary operations are increasingly performed in higher-risk patients; however, surgical revascularization is nearly twice as safe in current practice compared with a decade ago.

To graft or not to graft? Do coronary artery characteristics influence early outcomes of coronary artery bypass surgery? Analysis of coronary anastomoses of 5171 patients

OBJECTIVE Small coronary size and extensive atherosclerosis pose operative challenges during coronary artery bypass grafting. We investigated the influence of coronary characteristics on early operative outcome. METHODS Prospectively collected data for 5171 patients undergoing first-time coronary artery bypass grafting from April 1, 1999, to December 31, 2007, were analyzed. Coronary diameter estimated or probe-gauged intraoperatively was regarded as small if 1.25 mm or less. Coronary atherosclerosis was graded as none/mild or moderate/severe. Their influence on postoperative major adverse cardiac events, myocardial infarction or reintervention for graft failure, post-cardiotomy shock, and operative mortality, was investigated. RESULTS Of 14,019 coronary anastomoses, 4417 coronaries (31.5%) were small and 5895 coronaries (43.4%) had moderate/severe atherosclerosis. All grafted coronaries were small in 1091 patients (21.1%). Left anterior descending, circumflex, and right coronary arteries received grafts in 94.8% of patients (n = 4903), 74.3% of patients (n = 3842), and 72.5% of patients (n = 3751), with corresponding rates of 31.7%, 31.7%, and 32.6% for small-caliber arteries, 44.4%, 33.3%, and 47.2% for moderate/severe atherosclerosis, and 0.6%, 0.5%, and 3.4% for endarterectomy. Postoperative major adverse cardiac events occurred in 236 patients (4.6%). There was no clear evidence that small caliber of half or more distal anastomoses in a patient (odds ratio, 1.36; 95% confidence interval, 0.97-1.94; P = .07) increased the risk of a major adverse cardiac event, but incomplete revascularization (odds ratio, 1.87; 95% confidence interval, 1.03-3.39; P = .04) and moderate/severe atherosclerosis of the left anterior descending artery (odds ratio 1.37; 95% confidence interval, 1.01-1.87; P = .04) did increase the risk. CONCLUSION Grafting small coronaries did not significantly increase the risk of an early postoperative major adverse cardiac event, but incomplete revascularization did increase the risk. Our findings support grafting small coronaries when technically feasible to prevent incomplete revascularization.

Non-infective morbidity in diabetic patients undergoing coronary and heart valve surgery.

OBJECTIVE Studies of postoperative morbidity in diabetics have focussed on infection; however, autonomic and cardiovascular complications of diabetes potentially increase the risk for non-infective morbidity. We sought to investigate major non-infective early postoperative complications in diabetic patients. METHODS We identified diabetics who underwent CABG and/or valve operation from 1998 through 2007, and compared their clinical characteristics and outcome with a contemporaneous cohort of non-diabetic patients. RESULTS The demographic characteristics of 1145 diabetics were similar to 5534 non-diabetic patients (mean age 66+/-9 years vs 66+/-10 years, p=0.45, female 27.5% vs 26.7%, p=0.59, respectively). Class III/IV angina symptoms (43.9% vs 34.9%, p<0.0001), intravenous nitrates therapy (10.4% vs 6.6%, p<0.0001), heart failure (24.8% vs 20.4%, p=0.001), prior myocardial infarction (37% vs 31%, p<0.0001), ejection fraction </=0.50 (34.5% vs 23.0%, p<0.0001), triple vessel disease (66.3% vs 54.8%, p<0.0001), renal insufficiency (3.6% vs 1.5%, p<0.0001) and peripheral vascular disease (16.1% vs 8.7%) were prevalent amongst diabetics. The predominant operation was CABG (diabetic 84.8% vs non-diabetic 73.9%). Low cardiac output (28.3% vs 24.0%, p=0.002), renal dialysis (2.0% vs 0.8%, p<0.0001) and cerebrovascular events (5.1% vs 3.8%, p=0.04) more often complicated recovery of diabetic patients, but operative mortality was similar for both groups. However, postoperative myocardial infarction was less common in diabetics (0.5% vs 1.4%, p=0.02). Diabetes was not a risk factor for the composite endpoint of major non-infective morbidity and operative mortality (OR 1.15, 95% CI 0.97-1.37, p=0.10). Diabetic patients were prone to longer postoperative hospitalisation (9.7+/-10.5 days vs 8.4+/-6.7 days, p<0.0001) and discharge to a convalescence facilities (9.8% vs 6.9%, p<0.0001). CONCLUSIONS Diabetic patients present for surgery with higher prevalence of cardiovascular risk factors and are more likely to develop major non-infective complications, including cardiac, renal and neurological dysfunction, even though diabetes does not directly influence non-infective postoperative morbidity following CABG and/or valve operations.

Comparison of the immediate post-operative outcome of two different myocardial protection strategies: antegrade–retrograde cold St Thomas blood cardioplegia versus intermittent cross-clamp fibrillation

The objective of this study was to compare the immediate post-operative outcome of two myocardial protection strategies. Data of consecutive elective first time coronary artery bypass grafting (CABG) were analysed: Group A (n=671, antegrade-retrograde cold St Thomas blood cardioplegia) and Group B (n=783, intermittent cross-clamp fibrillation). Age, angina class, myocardial infarction (MI), pre-operative rhythm, respiratory disease, smoking, diabetes mellitus (DM), hypertension (HT), renal function, cerebrovascular disease, body mass index (BMI) and Parsonnet score were comparable. Significant differences existed in gender (P=0.02), peripheral vascular disease (PVD) (P=0.04), heart failure class (P=0.0001), left ventricular (LV) function (P=0.01), disease severity (P=0.02), left main stem (LMS) (P=0.02) and preinduction intra-aortic balloon pump(IABP) (P=0.08). Group A had more grafts (P=0.008), longer bypass (P=0.0001) and cross-clamp time (P=0.0001). Post-operative inotrope, MI, arrhythmias, neurological, renal complications, multi-organ failure, sternal re-wiring, ventilation, length of stay and mortality were comparable. There was higher IABP usage and longer intensive therapy unit (ITU) stay (P=0.01) in Group B. Chronic obstructive airway disease (COAD), renal dysfunction, cross-clamp time, bypass time, post-operative inotrope or IABP and re-exploration predicted longer ITU stay. Intermittent cross-clamp fibrillation is a versatile and cost-effective method of myocardial protection, with the immediate post-operative outcome comparable to antegrade-retrograde cold St Thomas blood cardioplegia in elective first-time CABG.

Intensive care unit readmission after elective coronary artery bypass grafting.

Prospective data of 3,120 consecutive patients who had elective coronary artery bypass were analyzed to identify patient profile, cost, outcome and predictors of those readmitted to the intensive care unit. Group A (n = 3,002) had a single intensive care unit admission and group B (n = 118) were readmitted within 30 days after surgery. Parsonnet score, EuroSCORE, age, body mass index, chronic obstructive airway disease, peripheral vascular disease, renal dysfunction, unstable angina, congestive cardiac failure, and poor left ventricular function were higher in group B. Bypass and crossclamp times were longer, and the prevalence of inotropic and balloon pump support, arrhythmias, myocardial infarction, re-exploration, blood loss and transfusion, cerebrovascular accident, wound infection, sternal dehiscence, and multisystem failure were higher in group B. Despite a 4-fold increase in cost of care, the mortality rate (32.4%) of patients readmitted to intensive care was 23-times higher than routine patients (1.4%). Crossclamp time > 80 min, Parsonnet score > 10, EuroSCORE > 9, sternal dehiscence, ventricular arrhythmias, and renal failure predicted readmission.

Systemic inflammatory response after cardiopulmonary bypass: the mediators of leukocyte-endothelial adhesion

Any surgery carries the risk of post-operative systemic inflammatory reaction. However, in cardiac surgery, the use of the bypass machine multiplies the risk many times over. The clinical manifestations can vary from insignificant transient organ dysfunction to life-threatening multi-organ failure. Surgical trauma, contact activation of leukocytes and platelets in the cardiopulmonary bypass circuit, release of activated neutrophils from the pulmonary bed, endotoxins released from the gut, and reperfusion injury have all been implicated as triggering factors. This complex inflammatory response involves the release of initiators from different cascades that activate neutrophils causing them to marginate and adhere to the endolthelium, transmigrate across the endothelial lining and finally degranulate in tissues. Once leukocyte activation and adhesion occurs, transmigration, degranulation and tissue damage become inevitable. The activation and adhesion are two steps where potential therapeutic intervention c...

Does aortic valve replacement mitigate the risk of preoperative heart failure

Congestive heart failure complicating aortic valve disease has been reported to increase the operative mortality associated with aortic valve replacement. To determine whether this adverse effect remains late after aortic valve replacement, we analyzed prospectively collected and survival data of 849 patients who underwent aortic valve replacement between 1999 and 2008. There were 243 (29%) cases of heart failure preoperatively (138 current and 105 prior). Both operative and late mortality rates (up to 10 years) were significantly higher in heart failure patients. Current congestive heart failure caused a 3-fold increase in operative mortality and an 86% increase in late mortality, whereas previous history of heart failure caused a doubling of late mortality. Preoperative heart failure still compromises early and late survival after aortic valve replacement. Surgery should be considered early in patients with aortic valve disease and deferred, when possible, in those with frank heart failure.