Editor, The preoperative assessment of the likelihood of a postoperative cardiac event is complex.1 The Revised Cardiac Risk Index (RCRI) is a commonly used scoring system for the stratification of cardiac risk of patients undergoing major non-cardiac surgery.2 The RCRI scores patients according to six clinical categories: high-risk surgery (thoracic, abdominal and supra-inguinal vascular surgery); history of ischaemic heart disease (IHD); history of congestive heart failure; cerebrovascular disease; insulin-dependent diabetes; and renal failure. Since the publication of the original article in 1999, the RCRI has become a widely used stratification tool for cardiac risk. A recent meta-analysis has examined the predictive value of the RCRI in these studies.3 It concluded that the RCRI performed moderately well at discriminating between low and high perioperative risk. However, the authors felt that it performed poorly in vascular cohorts, and that the studies included were of variable quality. This report highlights the need for further studies evaluating the RCRI. We report the results of a single centre observational study of consecutive patients undergoing major vascular surgery (aortic surgery, infra-inguinal bypass surgery, amputation). Ethical approval for this study [REC reference number 04/193(1)] was provided by the West of Scotland Research Ethics Committee (Chairperson Dr A Binning) on 2 March 2004. All patients gave written consent to the study. The patients were preoperatively scored according to the RCRI criteria.2 The presence of other risk factors was obtained from the patient's history and medical records. Operations were recorded as elective or expedited (within 3 weeks of initial presentation). Patients operated as an emergency, within 24 h of an unplanned admission, were excluded. Postoperative screening for cardiac events was performed by daily clinical assessment, serial ECGs and troponin I measurement. The primary outcomes were major adverse cardiac event (MACE) (non-fatal myocardial infarction and cardiac mortality) and all-cause mortality. Patients were followed-up for 6 weeks following surgery. Statistical analysis was performed using SPSS (Version 15) statistical software package (SPSS, Chicago, IL). Categorical variables are presented with totals and percentages, and analysed with Chi-square, Fisher's exact test or Mann–Whitney test as appropriate. Receiver operating characteristic (ROC) curves were plotted to model the efficacy of the RCRI. The area under the curve (AUC) was calculated. A total of 252 patients were included in the study: aortic surgery 25.8%; bypass surgery 39.7%; and lower limb amputation 34.5%. Thirty-nine patients (15.5%) had a postoperative MACE, and 20 patients (7.9%) died within the postoperative 6-week period. Applying the RCRI to the cohort as a whole, the rate of MACE for RCRI class 1, 2, 3 and 4 was 13.4, 14.9, 18.6 and 16.7%, respectively (P = 0.858) (Table 1). Similarly, the rate of perioperative mortality for these groups was 7.3, 9.2, 6.8 and 8.3%, respectively (P = 0.951). Analysis of the RCRI components revealed that no individual factor predicted postoperative MACE. Mortality was higher in patients with insulin therapy (18.2 vs. 6.4%, P = 0.020), and a preoperative creatinine of more than 2 mg dl−1 (30 vs. 7%, P = 0.036). Analysis of other risk factors not included in the RCRI showed that age at of least 70 years (P = 0.002), a history of hypertension (P = 0.010), preoperative anaemia (P < 0.001) and expedited surgery (P = 0.024) had a higher rate of postoperative MACE (Table 2). Furthermore, age of at least 70 years (P = 0.028), diabetes (type I and II) ((P = 0.013), estimated glomerular filtration rate (GFR) less than 60 ml min−1 (P = 0.009), chronic obstructive pulmonary disease (P = 0.043), preoperative anaemia (P = 0.025) and expedited surgery (P = 0.020) were associated with an increased rate of postoperative death. The area under the ROC curve for the RCRI score was calculated for the endpoints. The AUC for perioperative MACE was 0.538 and 0.501 for perioperative mortality. The same analysis was performed, amending the RCRI to consider all included vascular operation groups as high risk. The AUCs were not improved for perioperative MACE (0.507) or mortality (0.473).Table 1: Primary endpoints by Revised Cardiac Risk Index (RCRI) classTable 2: Patient characteristics and predictors of major adverse cardiac eventThe prediction of postoperative cardiac morbidity is multifactorial. Patient comorbidity, operation type, perioperative stress and postoperative factors are all influential in the pathogenesis of postoperative MACE.4 The RCRI includes patients factors (IHD, cardiac failure, cerebrovascular disease and insulin dependent diabetes), preoperative renal impairment (creatinine >2 mg dl−1) and type of surgery. These factors were found to be the most significant predictors of postoperative MACE in a derivation cohort of 2893 patients and the model was validated in a cohort of 1422 patients. Procedure types included thoracic, orthopaedic, vascular and abdominal surgery. The rates of major cardiac morbidity in the derivation and validation cohorts were 2 and 2.5%, respectively. These rates are considerably lower than in our study group, perhaps reflecting the heterogeneous nature of the procedures examined and a healthier study population. Why then has it performed so poorly in our cohort? Firstly, the RCRI defines high-risk surgery as intrathoracic, intraperitoneal and suprainguinal vascular surgery. In our cohort, patients undergoing high-risk surgery, as defined by the RCRI, had a lower MACE rate and improved perioperative survival. This can be explained as the high-risk patients were undergoing elective aortic surgery, yet patients undergoing lower limb revascularisation or amputation were considered as low-risk surgery. However, removing this ‘high-risk surgery’ parameter from the model did not improve the predictive efficacy. Secondly, patients with peripheral vascular disease have a notoriously high level of subclinical cardiac disease.5 The absence of clinical manifestations of cardiac disease may in part be due to their physiological exercise limitations.6 This is likely to ‘underscore’ patients with vascular disease, therefore underestimating the risks of postoperative cardiac events. The reliance on the RCRI has been questioned in the recently published combined European Society of Cardiology (ESC)/European Society of Anaesthesiology (ESA) guidelines on the preoperative cardiac risk assessment and for patients undergoing noncardiac surgery, due to its ‘suboptimal’ performance in patients with multiple risk factors.7 With this in mind, we conclude from our prospectively gathered cohort study that the RCRI performs poorly in predicting postoperative cardiac morbidity and mortality following vascular surgery. Acknowledgements relating to this article Assistance with the letter: The authors would like to thank Prof Colin Berry and Prof Alan Jardine, University of Glasgow, for their support in the study and Dr John McClure, University of Glasgow, for statistical advice. Financial support and sponsorship: All funding was from departmental sources. Conflicts of interest: none. Presentation: none.

The preoperative assessment of the likelihood of a postoperative cardiac event is complex. The Revised Cardiac Risk Index (RCRI) is a commonly used scoring system for the stratification of cardiac risk of patients undergoing major non-cardiac surgery. The RCRI scores patients according to six clinical categories: high-risk surgery (thoracic, abdominal and supra-inguinal vascular surgery); history of ischaemic heart disease (IHD); history of congestive heart failure; cerebrovascular disease; insulin-dependent diabetes; and renal failure. Since the publication of the original article in 1999, the RCRI has become a widely used stratification tool for cardiac risk. A recent meta-analysis has examined the predictive value of the RCRI in these studies. It concluded that the RCRI performed moderately well at discriminating between low and high perioperative risk. However, the authors felt that it performed poorly in vascular cohorts, and that the studies included were of variable quality. This report highlights the need for further studies evaluating the RCRI.

Objectives: Risk indices help quantify the risk of cardiovascular events and death prior to making decisions about prophylactic AAA repair. This paper aims to study the predictive capabilities of 5 validated indices. Design and methods: A prospective observational multi-centre cohort study from August 2005 to September 2007 in Glasgow recruited 106 consecutive patients undergoing elective open AAA repair. The Glasgow Aneurysm Score (GAS), Vascular physiology only Physiological and Operative Severity Score for enUmeration of Mortality (V(p)-POSSUM), Vascular Biochemical and Haematological Outcome Model (VBHOM), Revised Cardiac Risk Index (RCRI) and Preoperative Risk Score of the Estimation of Physiological Ability and Surgical Stress Score (PRS of E-PASS) were calculated. Indices were compared using receiver operating characteristic (ROC) analysis and area under the curve (AUC) estimates. End points were all-cause mortality, Major Adverse Cardiac Events (MACE) and cardiac death. Results: GAS, VBHOM and RCRI did not predict outcome. V(p)-POSSUM predicted MACE (AUC = 0.681), cardiac death (AUC = 0.762) and all-cause mortality (AUC = 0.780), as did E-PASS (AUC = 0.682, 0.821, 0.703 for MACE, cardiac death and all-cause mortality respectively). Conclusion: Whilst V(p)-POSSUM and E-PASS predicted outcome, the less complex RCRI and GAS performed poorly which questions the utility of decision making based on these surgical risk indices.

Objective: The aim of this study was to determine if a single preoperative B-type natriuretic peptide (BNP) level correlated with perioperative cardiac events, cardiac death, and all-cause mortality in elective open abdominal aortic aneurysm (AAA) repair in the short term, intermediate term, and long term.Methods: A prospective, 2-year multicenter observational cohort study in the three vascular units in Glasgow was performed. All patients who were admitted for elective open AAA repair were recruited. Preoperative BNP levels were performed and batch analyzed at the end of the study. Postoperative screening for cardiac events (nonfatal myocardial infarction and cardiac death) was performed at 2, 5, and 30 days. Follow-up for all-cause mortality was sustained to a minimum of 3 years, where possible.Results: A total of 106 of 111 patients were recruited. Median BNP concentrations were higher in the 16 patients (15%) with immediate postoperative cardiac events (P = .001) and the five with cardiac death (P = .043). Area under the receiver-operating characteristic (AUC) curve analysis indicated BNP concentrations of 99.5 pg/mL best predicted cardiac events (AUC, 0.927), and 448 pg/mL predicted cardiac death (AUC, 0.963). BNP also predicted all-cause mortality in the short-term (P = .028), intermediate-term (P < .001), and long-term (P < .001) postoperative periods.Conclusions: Preoperative serum BNP concentration predicted postoperative cardiac events, cardiac death, and all-cause mortality in patients undergoing elective open AAA repair on short-term, intermediate-term, and long-term follow-up on an individual basis with greater accuracy than currently available risk prediction tools. (J Vasc Surg 2013; 57: 345-53.)

Nicorandil is an antianginal medication increasingly used in the treatment of severe ischemic heart disease. It has been implicated in the pathogenesis of perianal and perioral ulceration. We report 2 patients with atypical gastrointestinal ulceration due to nicorandil.

OBJECTIVES:To determine the tissue penetration of vancomycin into perivascular fat and arterial wall during a continuous infusion of vancomycin, given as prophylaxis for vascular surgery.PATIENTS AND METHODS:Patients undergoing arterial reconstruction requiring antibiotic prophylaxis were included. Patients received a loading infusion of vancomycin the evening prior to surgery followed by a continuous 24 h infusion, calculated according to renal function. Three peri-operative serum samples and intra-operative perivascular fat and arterial wall samples were collected for vancomycin assay.RESULTS:Twenty-eight patients were included. Three serum samples were obtained from all patients, fat samples were available from 27 (96.4%) patients and vessel wall samples were available from 23 (82.1%) patients. Serum vancomycin concentrations were maintained within a relatively narrow range, while fat and arterial wall concentrations were highly variable.CONCLUSIONS:This study has shown that prophylactic administration of vancomycin with a loading infusion followed by a continuous infusion before and during vascular surgery achieves serum and vascular tissue concentrations that are above the MICs for most common organisms implicated in post-operative graft infection. However, penetration into perivascular fat tissues is poor.

Background. The prediction of long-term survival after surgery is complex. Natriuretic peptides can predict short-term postoperative cardiac morbidity and mortality. This study aims to determine the long-term prognostic significance of preoperative B-type natriuretic peptide (BNP) concentration after major non-cardiac surgery.Methods. We conducted a prospective single-centre observational cohort study in a West of Scotland teaching hospital. Three hundred and forty-five patients undergoing major non-cardiac surgery were included. The primary endpoint was long-term all-cause mortality.Results. Overall survival was 67.8% (234/345), with 27 postoperative deaths (within 42 days) and 84 deaths at subsequent follow-up (median follow-up 953 days). A BNP concentration of >87.5 pg ml(-1) best predicted mortality, and the mean survival of patients with an elevated BNP (>87.5 pg ml(-1)) was 731.9 (95% CI 613.6-850.2) days compared with 1284.6 days [(95% CI 1219.3-1350.0), P<0.001] in patients with a BNP<87.5 pg ml(-1). BNP was an independent predictor of survival.Conclusions. BNP is an independent predictor of long-term survival after major non-cardiac surgery. A simple preoperative blood test can provide predictive information on future risk of death, and potentially has a role in preoperative risk assessment.

BACKGROUND:Twelve-lead electrocardiography is a standard preoperative investigation for patients undergoing major surgery. There is uncertainty and debate over the usefulness of this test for stratifying postoperative cardiac risk. The aim of this study was to investigate the correlation between an abnormal electrocardiogram (ECG) and the postoperative cardiac event rate. METHODS:A prospective single-center observational cohort study in patients undergoing major noncardiac surgery was performed. ECGs were analyzed at the end of the study by a cardiologist and a clinician blinded to the clinical outcomes. The primary endpoints were a major adverse cardiac event (MACE), defined as nonfatal myocardial infarction or cardiac death, and perioperative mortality. RESULTS:A total of 345 patients were included, who had undergone aortic surgery 25.8%, lower limb bypass 29.0%, amputation 25.2%, or laparotomy 20.0%. An abnormal ECG was present in 141 (40.9%) patients. MACE occurred in 46 (13.3%) cases. Patients with an abnormal ECG had a significantly higher incidence of MACE (21.6 vs. 8.3%, P < 0.001). Multivariate analysis showed that left ventricular strain and a prolonged QTc interval (>440 ms) were independent predictors of postoperative adverse events. Among patients with no prior history of ischemic heart disease, those with an abnormal ECG had a higher MACE rate (20.3%) than those patients with a normal ECG (8.6%) (P = 0.01). CONCLUSION:Preoperative electrocardiography is a useful screening test for predicting perioperative cardiac events. Patients with an abnormal ECG but without a prior history of heart disease are a high-risk group potentially amenable to intervention and risk reduction.

Introduction The 12 lead electrocardiogram (ECG) is a standard pre-operative investigation for patients undergoing major surgery. A number of recent publications have questioned the predictive value for post-operative cardiac risk. The aim of this study is to investigate the correlation between an abnormal ECG and a post-operative major adverse cardiac event (MACE) and mortality. Methods A prospective single centre observational cohort study of 345 patients undergoing major non-cardiac surgery between January 2004 and August 2006 was performed. Patients underwent standard pre-operative assessment including an ECG. Screening for post-operative events was carried out with serial ECG and troponin measurement. Primary end-points were MACE (cardiac death and non-fatal myocardial infarction) and all-cause mortality. Results Three hundred and forty-five patients were included in the study, performed between January 2004 and August 2006. 276 (80.0%) patients underwent a vascular procedure (aortic surgery 25.8%, lower limb bypass 29.8% and amputation 25.2%) and 69 (20.0%) patients underwent laparotomy. An abnormal ECG (Abstract 110 Table 1) was present in 141 (40.9%) patients. MACE was observed in 46 (13.3) patients, and 27 (7.8%) patients died in the post-operative period. Patients with an abnormal ECG had a higher incidence of MACE (22.0% vs 7.4%, p<0.001), and higher mortality rate (12.1% vs 9.8%, p=0.015). Univariate analysis shows that AF, strain and prolonged QTc interval predict post-operative events. Multivariate analysis of clinical variables and ECG abnormalities showed that strain, prolonged QTc and hypertension independently predicted post-operative MACE. Conclusion This study shows that ECG abnormalities were more predictive than traditional clinical variables for post-operative MACE, and therefore confirms that an ECG remains a useful adjunct in pre-operative assessment before surgery. An abnormal ECG confers a threefold increase risk of post-operative MACE. This may allow improved pre-operative optimisation and enhanced peri-operative care to reduce the event rates.

Prosthetic graft infection is a devastating complication of vascular surgery that occurs in 3%-5% of clean prosthetic procedures. Staphylococci are the most frequently isolated pathogens, and thus surgical prophylaxis regimens often include vancomycin. However, the efficacy of these regimens in ensuring a required concentration of antibiotic is uncertain. This study aimed to determine if a continuous vancomycin infusion regimen administered perioperatively as surgical prophylaxis for vascular procedures maintained an adequate serum concentration. Thirty-four consecutive patients undergoing a vascular procedure requiring a prosthetic graft or patch were given vancomycin prophylaxis. Each patient received a loading dose calculated according to body weight 12 hours before surgery. A 24-hour continuous infusion was then started, based on calculated creatinine clearance. Serum vancomycin concentrations were checked on induction of anesthesia, 2 hours postoperatively, and at the end of the infusion. Perioperative fluid administration and blood loss were recorded. An estimated creatinine clearance was repeated on the second postoperative day. Of the 34 patients recruited, 7 did not have the anticipated procedure and 6 patients had incomplete sample collection. Twenty-one patients with complete sample collection were analyzed. The target concentration (10-25 mg/L) was achieved in 81% of all samples. All patients achieved the target concentration at 1 or more time points. The regimen employed provided appropriate concentrations at the time of intervention. No potentially toxic concentrations or adverse reactions to vancomycin were encountered. Vancomycin given as a continuous infusion delivers adequate serum concentration. Long-term graft infection rates are needed to show a clinical effect.

Background: It is common practice to take a specimen of pus for microscopy and bacterial culture during drainage of abscesses. The aim of this study was to determine if routine culture and sensitivity had any therapeutic value in the care of patients with non-perianal cutaneous abscesses. Patients and methods: A retrospective analysis of all patients undergoing drainage of a cutaneous abscess during a two year period () Line 2003 - June 2005) was performed. Patients were identified from the hospital database and theatre records, and those with perianal, pilonidal or surgical wound sepsis were excluded. Notes were reviewed for clinical details, culture results, subsequent admissions and attendance at follow-up. Results: Of the 239 patients treated during this period, 74 patients had 77 operations to drain abscesses that matched the inclusion criteria. Specimens were sent from 52 (67.5%) procedures. Only 65.4% had an organism identified, of which methicillin-sensitive Staphylococcus aureus (MSSA) was the most commonly isolated organism (36.5%). Forty-one point six per cent of patients received antibiotics as part of their treatment. The results of the bacterial culture and antibiotic sensitivities were not known prior to discharge of any patient. Conclusion: This study shows that bacteriology swabs are frequently taken during incision and drainage of non-perianal cutaneous abscesses and had little impact on the subsequent treatment, though these results may not be applicable to immune-compromised patients.

BACKGROUND:The objective of this study was to determine whether measurement of B-type natriuretic peptide (BNP) concentration before operation could be used to predict perioperative cardiac morbidity.METHODS:A prospective derivation study was performed in high-risk patients undergoing major non-cardiac surgery, with a subsequent validation study. A venous blood sample was taken the day before surgery for measurement of plasma BNP concentration. Screening for cardiac events (non-fatal myocardial infarction and cardiac death) was performed using clinical criteria, cardiac troponin I analysis and serial electrocardiography.RESULTS:Forty-one patients were recruited to the derivation cohort and 149 to the validation cohort. In the derivation cohort, the median (interquartile range) BNP concentration in the 11 patients who had a postoperative cardiac event was 210 (165-380) pg/ml, compared with 34.5 (14-70) pg/ml in those with no cardiac complications (P < 0.001). In the validation cohort, the median BNP concentration in the 15 patients who had a cardiac event was 351 (127-1034) pg/ml, compared with 30.5 (11-79.5) pg/ml in the remainder (P < 0.001). BNP concentration remained a significant outcome predictor in multivariable analysis (P < 0.001). Using receiver-operator curve analysis it was calculated that a BNP concentration of 108.5 pg/ml best predicted the likelihood of cardiac events, with a sensitivity and specificity of 87 per cent each.CONCLUSION:Preoperative serum BNP concentration predicted postoperative cardiac events in patients undergoing major non-cardiac surgery independently of other risk factors.

A liquid chromatography-mass spectrometry (LC-MS) method was developed for the analysis of vancomycin (VCM) in human serum. The method was based on full scan data with extracted ions for the accurate masses of VCM and the atenolol internal standard obtained by Fourier transform MS. VCM was extracted from serum using strong cation exchange (SCX) solid phase extraction (SPE). The method was found to be linear in the range 0.05-10 microg/ml, which was adequate for quantification of VCM in serum samples, with a limit of quantification (LOQ) of 0.005 microg/ml and a limit of detection (LOD) of 0.001 microg/ml. Intra-day precision (n=5) was +/-3.5%, +/-2.5%, +/-0.7% at 0.05, 0.5 and 5 microg/ml, respectively. Inter-day precision (n=5) was +/-7.6%, +/-6.4%, +/-3.9% at 0.05, 0.5 and 5 microg/ml, respectively. The process efficiency for VCM was in the range 89.2-98.1% with the recovery for the atenolol internal standard (IS) being 97.3%. The method was used to determine VCM levels in patients during peri-operative infusion of the drug, which was found to result in drug levels within the required therapeutic window.

ObjectivesThe objective of this study was to ascertain the benefit of routine pre-operative cardiac troponin I (cTnI) measurement in patients undergoing major lower extremity amputation for critical limb ischaemia.DesignThis was a prospective, blinded observational study.MethodsAll patients scheduled for lower extremity amputation, without evidence of unstable coronary artery disease were recruited prospectively over a period of 1 year. In addition to routine pre-operative evaluation, a blood sample was taken for measurement of serum cTnI. Post-operative screening was conducted for cardiac events with patients followed up to 6 weeks.ResultsTen of the 44 patients included suffered a non-fatal myocardial infarction or died from a cardiac cause post-operatively. A rise in pre-operative cTnI was associated with a very poor outcome (two cardiac deaths and one post-operative myocardial infarction) and was the only significant predictor of post-operative cardiac events.ConclusionRoutine pre-operative cTnI measurement may be of use to identify patients at high risk of cardiac complication who would benefit from optimization of cardiac status or in whom surgery could be deferred.