Parsonnet Score Research Articles

Is the female gender an independent predictor of adverse outcome after off-pump coronary artery bypass grafting?

Background The female gender is an independent predictor of adverse outcome after conventional coronary artery bypass grafting using cardiopulmonary bypass. The aim of this study is to assess the effect of the female gender on the outcome after off-pump coronary artery bypass (OPCAB) surgery. Methods This study is a retrospective review of 413 consecutive patients (181 women and 232 men) who underwent OPCAB between January 1999 and May 2001. Adverse outcomes were divided into minor adverse outcomes (MINAO), major adverse outcomes (MAJAO), and prolonged length of stay (PLOS) more than 7 days. MINAO included atrial fibrillation, respiratory complications except adult respiratory distress syndrome, and any wound infection except mediastinitis. MAJAO included stroke, myocardial infarction, renal failure, adult respiratory distress syndrome, mediastinitis, low cardiac output, mechanical ventilation more than 24 hours, intensive therapy unit stay more than 24 hours, gastrointestinal complications, cardiorespiratory arrest, and mortality within 30 days. Preoperative and intraoperative variables were evaluated as predictors of MINAO, MAJAO, and PLOS by univariate and multivariate analyses. Results The groups were matched for age and Parsonnet score–predicted mortality. However, the women had a higher incidence of chronic obstructive airway disease ( p = 0.04), diabetes ( p = 0.01), obesity ( p = 0.000), peripheral vascular disease ( p = 0.000), hypertension ( p = 0.000), unstable angina ( p = 0.005), history of previous failed nonsurgical intervention ( p = 0.02), and nonelective operation ( p = 0.000). There were a fewer number of grafts performed in the female group (2.8 vs 3.4, p = 0.000), with the circumflex territory being revascularised less frequently ( p = 0.001). Univariate analysis identified the female gender to be a predictor of only MINAO ( p = 0.001) and PLOS ( p = 0.000). However, with multivariate analysis, female gender was not found to be an independent predictor of MINAO, MAJAO, or PLOS. Conclusions In OPCAB, the female gender is not an independent predictor of MINAO, MAJAO, or PLOS.

Lower endotoxin immunity predicts increased cognitive dysfunction in elderly patients after cardiac surgery.

Although coronary artery bypass graft surgery (CABG) improves the quality of life and functional capacity for numerous patients, many also exhibit impairment in cognitive function immediately after surgery. Although the etiology of this cognitive decline is multifactorial, the inflammatory response to the primary insult may modulate the extent of dysfunction. Patients with low preoperative levels of anti-endotoxin core antibody (EndoCAb) are more likely to experience adverse outcomes, suggesting that decreased immunity to endotoxin causes a heightened release of inflammatory mediators. We therefore sought to determine the association of decreased EndoCAb and the incidence of postoperative cognitive decline. EndoCAb levels were measured before surgery in 460 patients undergoing elective CABG. Cognitive function was measured preoperatively and 6 weeks postoperatively. Multivariable analysis accounted for the effects of age, Parsonnet score, sex, body mass index, baseline cognition, years of education, history of hypertension, bypass time, cross-clamp time, and number of grafts. At 6-week follow-up, 122 patients (36%) showed cognitive decline. Lower preoperative EndoCAb levels were associated with a greater incidence and severity of postoperative cognitive decline. The elderly with decreased endotoxin immunity are particularly susceptible to this decline (relative risk=1.97 for age >64). Reduced preoperative endotoxin immunity is a predictor of increased postoperative cognitive dysfunction in patients undergoing CABG, particularly in those >60 years old. Interventions that increase IgM EndoCAb levels might improve cognitive function after cardiac surgery.

Severe ischemic early liver injury after cardiac surgery

Background. The epidemiology, pathogenesis and prognosis of severe ischemic early liver injury (SIELI) after cardiac surgery are poorly understood. Accordingly, we studied patients whose alanine transaminase (ALT) concentration acutely increased above 500 IU/l in the immediate postoperative period and compared these patients to two control groups matched for preoperative and immediate postoperative characteristics. Methods. We used a prospective database of 1,800 consecutive cardiac surgical cases to identify the study groups. Group I was made up of 20 patients with ALT levels above 500 IU/L in the acute postoperative stage (SIELI). Preoperative liver tests were normal in all these patients. Group II was obtained by identifying 20 control cases whose age, type of surgery, NYHA classification, and Parsonnet score matched Group I (preoperative controls). Group III was obtained by identifying 20 patients who developed postoperative acute renal failure and shock (ARF/shock; postoperative controls) but no enzyme evidence of hepatic injury. Results. Acute renal failure, a low cardiac index (CI) state, and mortality were more common in SIELI and ARF/Shock patients compared with preoperative controls (all p values less than 0.01). Peak postoperative pulmonary artery occlusion (PAOP) and central venous (CVP) pressures were also higher in SIELI and ARF/Shock patients than controls (all p values less than 0.02). A higher dose of norepinephrine and milrinone were required to maintain blood pressure and cardiac output in SIELI and ARF/shock patients than preoperative controls (all p values less than 0.005). SIELI patients, however, differed from ARF/Shock patients in that they had a higher preoperative NYHA class and a greater incidence of hypertension and diabetes. Stepwise linear regression analysis identified a postoperative low CI and the presence of diabetes as the only predictors of peak ALT value ( p less than 0.05). Multivariate logistic regression analysis identified female gender as being associated with a higher likelihood of SIELI (odds ratio: 6.13; 95% CI 1.08 to 34.82) Conclusions. SIELI after cardiac surgery carries a high mortality and is strongly associated with a low cardiac output and increased filling pressures, suggesting that liver ischemia induced by a combination of decreased perfusion and congestion is fundamental to its pathogenesis. A history of cardiac failure, diabetes, hypertension, and female gender may represent risk factors for its development and severity in the setting of a postoperative low cardiac output state.

Sigmoid capnometry in abdominal aortic aneurysm surgery

A reply EDITOR: We thank Dr Björck for his interest in our work [1] and for giving us the opportunity both to re-emphasize points made in our paper and to correct a reference mistake in the published version. We first apologize to Dr Björck for the reference error in the third paragraph of the discussion part where reference 10 should in fact be reference 19. Furthermore, we share Dr Björck's point of view that sigmoid tonometry monitoring in surgery for aortic aneurysm is best indicated in high-risk patients. In our study, patients included were at high risk with a Parsonnet score ≥4; six of our patients had a combined history of myocardial necrosis and severe chronic obstructive bronchopulmonary disease. The surgical procedure was also particularly difficult as attested by long surgical and clamping times. All these factors explain our high frequency of ischaemic colitis. These patients were selected voluntarily because the main objective of our study was to compare the sigmoid-to-arterial PCO2 gap with the mucosal aspect as assessed by colonoscopy, which is the reference diagnostic tool of ischaemic colitis. It was interesting to observe that patients with the highest PCO2 gap were those who developed the most severe postoperative ischaemic colitis. However, our study was not powerful enough to determine the limits of the PCO2 gap, thus not allowing us to distinguish a normal from an ischaemic intestinal mucosa. In our practice, we do not argue about the sole regional PCO2 but we compare it with arterial PCO2 since tissue PCO2 concentration is dependent on the PCO2 of the perfusing arterial blood. A regional-to-arterial PCO2 gap >4 kPa provides sufficient information suggesting bowel mucosal low flow associated with O2 uptake-to-supply dependency [2], a state known as dysoxia. In this study [1], endoscopically proven ischaemic colitis was shown for PCO2 gaps >6-8 kPa. This leads us to think that a sigmoid PCO2 >15 kPa, an upper technical limit with the Tonocap® as emphasized by Björck [3], is so high, that the intestinal mucosa obviously suffers from dysoxia, preventing any doubt or interpretation. We emphasize furthermore that in our hands PrCO2 rarely goes beyond 10-12 kPa [1]. We would like to point out that trends - rather than absolute PCO2 or pHi - much better reflect any underlying regional PCO2. Therefore, a high PCO2 gap, which persists after aortic declamping without any improvement in the initial postoperative period, will alert the clinicians to perform a colonoscopy. For this reason, automatic measurements of PCO2 are certainly of great help. We agree with Dr Björck that sigmoid capnometry in aortic surgery will be mostly valuable in high-risk patients, whereas further prospective and multicentre studies are required to determine the lower limit of the PCO2 gap associated with colitis dysoxia and the influence of therapeutic correction of a high PCO2 gap on the incidence of bowel injury. G. Lebuffe B. Vallet Department of Anaesthesia and Intensive Care Medicine; University Hospital; Claude Huriez Hospital; Lille, France

A case-control analysis of readmissions to the cardiac surgical intensive care unit.

To identify predictors of requirement for readmission to the intensive care unit (ICU) for patients undergoing cardiac surgery. The setting was a 17-bedded ICU in a tertiary level institute for specialist adult cardiorespiratory disease. The case notes and ICU charts of 65 ICU readmissions and 65 controls, matched for day of initial ICU discharge, were analysed. Patient variables assessed included preoperative risk stratification, ICU admission APACHE III score and intensive therapy interventions, complications and indication for readmission if readmitted. Twenty of 65 patients (31%) readmitted to the cardiac ICU died, compared with no mortality among the control group. Significant univariate determinants of ICU readmission (odds ratio, 95% confidence interval) included worse angina (1.38, 0.99-1.91) and dyspnoea (1.70, 1.10-2.61) classes and corresponding non-elective surgery (2.04, 1.31-3.19), higher Parsonnet score (1.06, 1.01-1.11) or EuroSCORE (1.14, 1.01-1.28), APACHE III score (1.03, 1.00-1.05), body mass index>27 (4.25, 1.43-12.63), non-usage of beta-blockers (1.53, 1.03-2.26), emergency resternotomy (5.00, 1.10-22.79), and lower haemoglobin (0.75, 0.58-0.96), higher required inspiratory oxygen (1.05, 1.02-1.08), and higher respiratory rate upon ICU discharge (1.09, 1.01-1.18). Renal failure, respiratory failure and cardiac arrest were the most common indications for ICU readmission. Thirty-five of 65 patients readmitted to the ICU required ventilation for a mean of 7.1 days. The mean ICU readmission duration for all 65 cases was 5.7 days. Readmission of cardiac surgical patients to the ICU is associated with high morbidity and mortality, and substantial resource consumption. Parsonnet or EuroSCORE risk stratification models in combination with obesity, operative urgency, resternotomy and respiratory indices at time of intended ICU discharge are strongly associated with readmission to ICU.

Off-pump coronary artery bypass grafting decreases morbidity and mortality in a selected group of high-risk patients

Background. The ideal indication for off-pump coronary artery bypass grafting (OPCABG) has yet to be defined. High-risk surgical patients may benefit the most when cardiopulmonary bypass (CPB), aortic cross clamping, and cardioplegic arrest are avoided. The aim of this study was to determine whether off-pump coronary artery bypass grafting might decrease the operative morbidity and mortality in a select group of high-risk patients with multivessel coronary artery disease. Methods. Utilizing a Parsonnet risk stratification model we analyzed prospectively collected data on a cohort of high-risk coronary artery disease patients, which were operated on with beating-heart technology by the same group of surgeons in a tertiary care university medical center. High-risk patients were defined as those with a Parsonnet score of 15 or greater. Results. Fifty-seven multivessel disease OPCABG patients (over a period of 2 years) had markedly increased Parsonnet scores (24.3 ± 10.6). The average ejection fraction of the patients was 42% (±12.3) and their age ranged from 52 to 85 years (mean 70.6 ± 10.4, 26% women). Unstable angina was present in 42 patients (74%) and 10 patients underwent OPCABG within 24 hours of the occurrence of acute myocardial infarction. In addition to severe coronary artery disease 32% of the patients presented with congestive heart failure, insulin-dependent diabetes (18%), renal failure (22%), peripheral vascular disease (31%), pulmonary disease (18%), and neurologic disorders (14%). An average of 2.6 ± 0.9 grafts/patient were performed and the posterior descending artery or marginal branches of the circumflex artery or both were grafted in 90%. The 30-day mortality rate was 3.5% (n = 2). Conclusions. OPCABG can be performed with a reasonable low morbidity and mortality in this select group of high-risk patients. OPCABG is a reasonable, and might even be preferable, operative strategy in this high-risk group of patients.

Increased endothelin-1 production in diabetic patients after cardioplegic arrest and reperfusion impairs coronary vascular reactivity: reversal by means of endothelin antagonism.

Evidence has accrued to suggest that diabetic patients face an increased risk of ischemic events and low output syndrome and might mount an inordinate response to ischemia and reperfusion. Because hyperglycemia is a potent stimulus for endothelin-1 production, we hypothesized that increased production, action, or both of endothelin-1 in diabetes might represent an important mediator of endothelial dysfunction in patients with that disease. To this aim, we compared the effects of cardioplegic arrest and reperfusion on coronary sinus effluent endothelin-1 levels and atrial arteriolar vascular responses in diabetic and case-matched nondiabetic patients undergoing coronary artery bypass grafting. In study 1 coronary sinus effluent endothelin-1 levels were assessed at baseline and at 1 and 10 minutes after reperfusion in 13 diabetic and 12 nondiabetic patients matched for age, ejection fraction, Parsonnet score, and crossclamp time. In study 2 vascular responses of atrial arterioles subjected to perioperative ischemia-reperfusion were evaluated with videomicroscopy. Atrial microvessels (from appendages) were obtained before and after removal of the aortic crossclamp, and vascular responses to exogenously administered endothelin-1 (10(-10) mol/L) and substance P (10(-8) mol/L) were studied in the presence or absence of BQ-123, an endothelin A receptor antagonist. Diabetic patients elaborated more endothelin-1 at 1 and 10 minutes after reperfusion (P =.01). Endothelin-1-mediated vasoconstriction was similar in diabetic and nondiabetic atrial microvessels before cardioplegic arrest and cardiopulmonary bypass. After cardiopulmonary bypass and reperfusion, endothelin-1-mediated vasoconstriction was enhanced in both groups; however, this response was greater in microvessels from diabetic patients (P =.02). BQ-123, the endothelin A antagonist, attenuated the effects of bypass and reperfusion on endothelin-1-mediated vasoconstriction in both groups (P =.01). Substance P-mediated vasodilatation was similar in diabetic and nondiabetic atrial microvessels before bypass. After bypass and reperfusion, substance P-mediated vasodilatation was diminished in both groups; however, this response was more pronounced in the diabetic group (P =.003). BQ-123 coincubation restored substance P-mediated vasodilatation in both groups. We determined the following: (1) the coronary effluent release of endothelin-1 is higher in diabetic than in nondiabetic patients after cardiopulmonary bypass and reperfusion; (2) diabetic coronary microvessels respond to bypass and reperfusion with greater endothelin-1-mediated vasoconstriction and diminished nitric oxide-mediated vasodilatation; and (3) these effects are attenuated by endothelin antagonism. Endothelin-1 might be an important mediator of ischemia-reperfusion injury in patients with diabetes. Furthermore, use of endothelin receptor antagonists might be a novel strategy for improving the resistance of the diabetic heart to cardioplegic arrest and reperfusion.

The association of complication type with mortality and prolonged stay after cardiac surgery with cardiopulmonary bypass.

Outcome after cardiac surgery varies depending on complication type. We therefore sought to determine the association between complication type, mortality, and length of stay in a large series of patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Multivariate logistic regression was used to test for differences between complication types in mortality and prolonged length of stay (>10 days) while controlling for preoperative and intraoperative risk factors. In 2609 consecutive cardiac surgical patients requiring CPB, the mortality rate was 3.6%; 36.5% had one or more complications, and 15.7% experienced an adverse outcome (death or prolonged length of stay). Multivariate logistic regression demonstrated that complication type was significantly associated with adverse outcome (P < 0.001) independent of Parsonnet score and CPB time (c-index = 0.80). The development of noncardiac complications only (Group NC) and cardiac complications with other organ involvement (Group B) significantly increased mortality and hospital and intensive care unit length of stay (P < 0.001) when compared with cardiac complications only (Group C). The incidences of adverse outcome in Groups C, NC, and B were 15%, 43%, and 67%, respectively; the mortality rates were 3%, 7%, and 20%, respectively. All these intergroup comparisons were significantly different (adjusted P < 0.05). Complications involving organs other than the heart appear to be more deleterious than cardiac complications alone, underscoring the need for strategies to reduce noncardiac complications. Complications, particularly when they involve organs other than just the heart, increase mortality and prolong the length of hospital stay after heart surgery, independent of a patient's preoperative risk factors and the duration of cardiopulmonary bypass. Strategies aimed at preventing damage to other organs during cardiac surgery need to be improved.

Isolated myocardial revascularization with intermittent aortic cross-clamping: experience with 800 cases

Background. We investigated the clinical outcome of elective and nonelective myocardial revascularization performed with intermittent aortic cross-clamping. Methods. Prospective data on 800 consecutive patients (from May 1996 to July 2000), who underwent isolated myocardial revascularization with intermittent aortic cross-clamping, were analyzed. A subgroup analysis was performed on the elective (n = 520), urgent (n = 226), and emergency (n = 54) procedures. Results. The elective group of patients had a mean age of 61.5 ± 9.46 years, mean Parsonnet score of 5.23 ± 5.1, and mean number of distal anastomoses of 3.22 ± 1.04. The hospital mortality was 0.57%. The urgent group of patients had a mean age of 63.06 ± 10.43 years, mean Parsonnet score of 6.73 ± 6.22, and mean number of distal anastomoses of 3.21 ± 1.04. The hospital mortality was 3.09%. The emergency group of patients had a mean age of 63.75 ± 9.63 years, mean Parsonnet score of 11.24 ± 11, and mean number of distal anastomoses of 2.87 ± 0.86. Hospital mortality was 5.55%. Postoperative hospital stay was 7.11 ± 5.47 days for the elective group, 7.59 ± 5.07 days for the urgent group, and 7.40 ± 4.01 days for the emergency group. Conclusions. Intermittent aortic cross-clamping is a safe technique both in elective and nonelective patients. The mortality and morbidity in the three subgroups analyzed reflects patients’ distribution against Parsonnet score.

Reoperative Coronary Bypass Surgery Using Normothermic Cardiopulmonary Bypass: Comparison with First-Time Procedures

Redo coronary artery bypass grafting (CABG) is characterized by increased patient risk compared with first-time CABG. The reason for higher risk is not completely understood but it is logically related to inadequate myocardial preservation evidenced by the higher incidence of postoperative low-output syndrome. We compared normothermic cardiopulmonary bypass with cold blood maintenance cardioplegia in both first-time and redo CABGs to determine whether this single approach is appropriate for both instances. Five hundred seventeen consecutive CABG patients were retrospectively reviewed. Four hundred fifty-four first-time CABG procedures were compared with 44 redo procedures. All aspects of the operation were identical including myocardial preservation. Retrospective univariant analysis of both groups followed. Three clinical features distinguished first-time versus redo CABG. These were previous percutaneous transluminal coronary angioplasty (first-time 19% vs redo 71%; P < 0.001), preoperative intra-aortic balloon pump (first-time 38% vs redo 71%; P < 0.001), and Parsonnet risk score (first-time 11.7+/-8.2 vs redo 19.2+/-8.8; P < 0.001). Operative mortality for redo CABG was higher than in first-time procedures (3.4% vs 6.4%; P = not significant), although small sample size limited statistical significance. The length of stay was statistically longer in redo patients (8.7+/-10.8 vs 6.0+/-5.1 days; P < 0.01) and is related to a higher Parsonnet score, increased postoperative pneumonia, and failed percutaneous transluminal coronary angioplasty before redo CABG. We conclude that redo CABG is a different operation from first-time procedures and requires enhanced myocardial preservation. Normothermic cardiopulmonary bypass with cold blood maintenance cardioplegia does not appear to achieve this goal.

Modified Ultrafiltration Reduces Morbidity After Adult Cardiac Operations

Background Extracorporeal circulation contributes to morbidity after open-heart surgery by causing a systemic inflammatory reaction. Modified ultrafiltration is a technique able to remove the fluid overload and inflammatory mediators associated with use of cardiopulmonary bypass. It has been shown to reduce morbidity after cardiac operations in children, but the impact on adult cardiac procedures is unknown. Methods and Results Five hundred seventy-three consecutive adult patients were prospectively randomized to either ultrafiltration after cardiopulmonary bypass (treatment) or to no ultrafiltration (control). Parsonnet score was used to assess the severity of the patients’ clinical conditions. Analysis was done with Student’s t test or Mann-Whitney U test for continuous variables and Fisher’s exact test or Pearson’s χ 2 for discrete variables. Hospital mortality was 2.5% (7 of 284) in the treatment group versus 3.8% (11 of 289) in the control group ( P =0.357). Hospital morbidity was lower in treated patients (66 of 284 [23.2%] versus 117 of 289 [40.5%], P =0.0001). Cardiac morbidity was similar (26 of 284 [9.1%] versus 35 of 289 [12.1%], P =0.251), whereas significantly lower rates of respiratory (20 of 284 [7.0%] versus 36 of 289 [12.5%], P =0.029), neurological (5 of 284 [1.8%] versus 14 of 289 [4.8%], P =0.039), and gastrointestinal (0 of 284 versus 4 of 289 [1.4%], P =0.044) complications were found in treated patients. Transfusion requirements were also lower in treated patients (1.66±2.6 versus 2.25±3.8 U/patient, P =0.039). Duration of intensive care (39.9±49.2 versus 46.3±72.8 hours, P =0.218) and hospital stay (7.6±3.5 versus 7.9±4.4 days, P =0.372) were comparable. Conclusions Modified ultrafiltration after cardiopulmonary bypass is associated with a lower prevalence of early morbidity and lower blood transfusion requirements. The impact on length of hospital stay needs further analysis. Routine application of modified ultrafiltration after adult cardiac operations is warranted.

Impact of age and Parsonnet Score on incidence and outcome of cardiac arrest following cardiac surgery

Rozario, C.; Powell, S.; Charman, S.; Osgathorp, J.; King, G.; Mackay, J. Author Information

Preoperative intraaortic balloon pumps in high-risk patients undergoing open heart surgery

Background. The use of the preoperative intraaortic balloon pump (IABP) in patients with severe left ventricular dysfunction or unstable angina with critical coronary anatomy is becoming more frequent as surgical casemix changes. The aim of this study was to determine the impact of preoperative IABP use on survival in high-risk patients having open heart surgery. Methods. Prospectively collected data for 645 consecutive patients were reviewed. Patients receiving an IABP were identified and grouped as follows: group A (preoperative IABP for high-risk nonemergent cases), group B (preoperative IABP for emergent cases), and group C (intra/postoperative IABP). Risk-adjusted hospital mortality rates in these three groups was compared using the modified Parsonnet score for preoperative risk stratification. Results. IABPs were used in 101 cases (16%). The predicted versus actual hospital mortality rate was 20% versus 5.7% in group A, 32.1% versus 47.6% in group B, and 12.6% versus 22.2% in group C (group A vs group B, p = 0.0014; group A vs group C, p = 0.012). IABP-related morbidity occurred in 3% of cases (all in group C). Conclusions. Risk-adjusted mortality was significantly lower in high-risk cases with preoperative IABPs compared with emergent cases and intraoperative/postoperative IABPs. We encourage the use of preoperative IABPs in selected high-risk patients.

Determinants of Intensive Care Unit Length of Stay After Coronary Artery Bypass Graft Surgery.

Abstract Objective: The purpose of this study is to identify independent preoperative, intraoperative, and postoperative determinants of intensive care unit (ICU) length of stay in patients undergoing coronary artery bypass graft (CABG) surgery and to evaluate the usefulness of a mortality risk scoring system, the Parsonnet score, as a prognostic indicator of ICU length of stay after CABG. Methods: A prospective nonrandomized sample of 109 consecutive patients was enrolled before CABG and followed prospectively until ICU discharge. Multivariate linear regression was used to identify factors independently associated with ICU length of stay. Results: One preoperative variable (Parsonnet score) and 4 postoperative variables (length of intubation, presence of arrhythmias, early hemodynamic instability, and 12-hour fluid balance) explained 45.6% of the variance in ICU length of stay. Intraoperative variables were not independent correlates of ICU length of stay. Classification as “extremely high” risk by Parsonnet scoring (score 20) yielded a positive predictive value of 84% for ICU stay >1 day. Negative predictive value was 42.8%. Conclusions: Preoperative and postoperative variables explained a large portion of the variance in ICU stay after CABG. Although the Parsonnet score was not helpful in identifying patients who require only a short ICU stay, it may help clinicians screen for patients likely to require stays >1 day and plan appropriate use of resources in the ICU. (Heart Lung® 2001;30:9-17.)

The relationship between predicted and actual cardiac surgical mortality: impact of risk grouping and individual surgeons.

To study the relationship between predicted and actual mortality in a cardiac surgical practice and to determine whether there is a consistent relationship across risk groups and surgeons. Risk information (Parsonnet score) was prospectively collected for 6213 consecutive adult patients undergoing cardiac surgery at one institution. The relationship between predicted mortality and actual mortality was analysed by risk group for all patients and for individual surgeons' practices. Predicted mortality was 10.2%. Actual mortality was 4.2%, giving a mortality ratio of 41% of predicted. This ratio was not consistent across the five major risk groups, ranging from 32% in moderate risk to 67% in very low risk patients. When analysed by individual surgical practices, the results were even more disparate, with a mortality index range between 0% for one surgeon's low risk patients to 150% for another surgeon's very low risk patients. The relationship between predicted and actual mortality at one institution may vary across the risk spectrum and between surgeons. This should be taken into account in preoperative risk assessment and informed patient consent. Individual surgeons may have strengths and weaknesses which are related to preoperative risk stratification.

Risk stratification for training in cardiac surgery.

There is a potential conflict of interest in providing the best possible outcome for patients undergoing cardiac surgery and good training for junior cardiac surgeons. We analysed training with reference to volume of work, risk stratification and outcome for consultant and trainee procedures. The Parsonnet system was used for risk stratification. A retrospective audit was performed for a 6-year period. During the study period, 6037 operations were performed, of which 2166 were carried out by trainees. Direct consultant assistance in a trainee operation varied between 17% and 51% and increased towards the end of the study period. Of the operations performed by trainees, 88% were CABG. The median Parsonnet score for consultant operations was 9 compared with 4 for trainees. Actual mortality was below predicted for all surgeons. Morbidity was also lowest for trainees (10%). With appropriate case selection, trainees in cardiac surgery can achieve good results. As training changes in the UK, trainees should receive increased supervised exposure to a wider range of procedure to compensate for a lower volume of workload.

Off-pump coronary operations can be safely taught to cardiothoracic trainees

Background. Off-pump coronary artery bypass (OPCAB) operations are evolving rapidly and becoming established in many cardiothoracic centers. For the technique to be widely applicable, teaching methods must be developed for surgical trainees. Early and midterm clinical outcomes of OPCAB performed at our institution by trainees as first operators under supervision were compared to those obtained in patients operated on by consultants. Methods. Analysis was undertaken on data prospectively inserted in the Patient Analysis & Tracking System. Of the 559 OPCAB operations performed between January 1997 and May 2000, 124 (22%) were carried out by a supervised trainee and 435 (78%) by a consultant. Results. There was no difference in age, sex, angina class, New York Heart Association functional class, or operative priority and extent of coronary artery disease in the two groups. More patients operated on by consultants had a history of congestive heart failure requiring medical therapy, significantly lower ejection fraction, and higher Parsonnet score compared with patients operated on by trainees. Early and midterm clinical results, in terms of morbidity and mortality, were similar in patients operated on by trainees or by consultants. Conclusions. Our data show no differences in early and midterm clinical outcome for patients undergoing OPCAB operations performed either by consultants or by trainees under supervision. The improvements in exposure and stabilization techniques, as well as the use of intracoronary shunts, have made it possible and safe to teach trainees off-pump multivessel coronary artery revascularization.

Target vessel revascularization without cardiopulmonary bypass in elderly high-risk patients

Background. Coronary artery bypass grafting in patients over 75 years is associated with high operative risk. Target vessel revascularization without cardiopulmonary bypass is a promising option for highly selected, older patients. However, the outcome remains uncertain. Methods. We investigated 44 patients over 75 years, matched for preoperative risk and left ventricular function, who underwent coronary artery bypass grafting either with or without cardiopulmonary bypass (CPB). We analyzed patients characteristics, Parsonnet score, EuroSCORE, short as well as midterm outcome and quality of life (freedom from recurrence of angina, antianginal therapy, sf36 test). Results. Perioperative mortality was higher in the patient group operated with CPB (15.9) as compared to patients operated without CPB (4.5%, p = 0.0226). Patients operated with cardiopulmonary bypass received more grafts (3.1 ± 0.1) than patients operated without cardiopulmonary bypass (1.6 ± 0.1, p = 0.0001) and and were more likely to undergo complete revascularization (with CPB 100%, without CPB 63.6%, p = 0.0010). Perioperative complications were more frequent and midterm survival was worse in the patient group operated with CPB (log rank p = 0.0228). Quality of life was comparable in both groups. Conclusions. The concept of incomplete target vessel revascularization of the culprit lesion seems to be a promising option for selected high-risk patients, predominantly due to lower perioperative mortality.

Determinants of intensive care unit length of stay after coronary artery bypass graft surgery

Objective: The purpose of this study is to identify independent preoperative, intraoperative, and postoperative determinants of intensive care unit (ICU) length of stay in patients undergoing coronary artery bypass graft (CABG) surgery and to evaluate the usefulness of a mortality risk scoring system, the Parsonnet score, as a prognostic indicator of ICU length of stay after CABG. Methods: A prospective nonrandomized sample of 109 consecutive patients was enrolled before CABG and followed prospectively until ICU discharge. Multivariate linear regression was used to identify factors independently associated with ICU length of stay. Results: One preoperative variable (Parsonnet score) and 4 postoperative variables (length of intubation, presence of arrhythmias, early hemodynamic instability, and 12-hour fluid balance) explained 45.6% of the variance in ICU length of stay. Intraoperative variables were not independent correlates of ICU length of stay. Classification as “extremely high” risk by Parsonnet scoring (score 20) yielded a positive predictive value of 84% for ICU stay >1 day. Negative predictive value was 42.8%. Conclusions: Preoperative and postoperative variables explained a large portion of the variance in ICU stay after CABG. Although the Parsonnet score was not helpful in identifying patients who require only a short ICU stay, it may help clinicians screen for patients likely to require stays >1 day and plan appropriate use of resources in the ICU. (Heart Lung® 2001;30:9-17.)

Perioperative Predictors of ICU and Hospital Costs in Coronary Artery Bypass Graft Surgery

Economic forces have precipitated intense interest in cost-saving practices for patients undergoing coronary artery bypass grafting (CABG). While several preoperative variables have been implicated in higher costs, few studies have included perioperative factors. This study evaluated the predictive power of a preoperative mortality risk measurement (Parsonnet score) and of early extubation (< or = 6 h from ICU admission) in determining ICU and hospital costs. Multivariate correlational design. University hospital in a large metropolitan area. All patients (n = 116) undergoing isolated CABG during a 6-month period were studied after the introduction of a clinical pathway. Clinical data were collected. Costs data were obtained retrospectively from the institutional data system and were derived from individual patient charges by application of department-specific cost-to-charge ratios. In multivariate logistic regression, Parsonnet score (per point odds ratio [OR], 1.09; confidence interval [CI], 1.03 to 1.17), in-hospital coronary angiography (OR, 3.51; CI, 1.23 to 10.01), delayed extubation (OR, 4.59; CI, 1.29 to 16.29), and presence of arrhythmia (OR, 3.50; CI, 1.15 to 10.64) were independent predictors of ICU costs. Only Parsonnet score (OR, 1.09; CI, 1.03 to 1.15) and cardiopulmonary bypass time (OR, 1.01; CI, 1.00 to 1.02) were independent predictors of hospital costs. The Parsonnet score is a useful indicator of both ICU and hospital costs. Early extubation is associated with decreased ICU costs, but is not independently predictive of hospital costs.