Usefulness of transthoracic echocardiography as a tool for risk stratification of patients undergoing major noncardiac surgery

Risk assessment in coronary patients undergoing abdominal nonvascular surgery

The aim of our study was to establish that the incidence of perioperative cardiac complications were in direct correlation with level of operative risk in coronary patients undergoing open abdominal nonvascular surgery with general anesthesia. Our prospective observational clinical study was composed of a group of 111 consecutive patients with angiographically-verified coronary artery disease, who were operated on at the University Clinical Center of Serbia. The patients were classified into four stratification subgroups by “Goldman’s Cardiac Risk Index” (CRI) in relation to the incidence of perioperative cardiac complications. Electrocardiography was performed immediately after surgery, on postoperative days 1, 2, 7 and one day before discharge from the hospital. All patients were followed to postoperative day 30. Statistical design was presented by Pearson’s χ2 test and binomial logistic regression. The main result was significant difference between the four stratification subgroups of coronary patients in the incidence of cardiac death up to the 30th postoperative day: I — 0/17 (0.0%) vs. II — 0/40 (0.0%) vs. III — 1/37 (2.7%) vs. IV — 2/17 (11.8%), (p<0.05). We concluded that the incidence of perioperative cardiac complications significantly increased with the degree of Goldman’s CRI. There was significant difference in the incidence of perioperative cardiac complications between the four Goldman’s stratification subgroups.

A review of risk scoring systems utilised in patients undergoing gastrointestinal surgery

INTRODUCTION

Adequate stratification and scoring of risk is essential to optimise clinical practice; the ability to predict operative mortality and morbidity is important. This review aims to outline the essential elements of available risk scoring systems in patients undergoing gastrointestinal surgery and their differences in order to enable effective utilisation.

METHODS

The English literature was searched over the last 50 years to provide an overview of systems pertaining to the adult surgical patient.

DISCUSSION

Scoring systems can provide objectivity and mortality prediction enabling communication and understanding of severity of illness. Incorporating subjective factors within scoring systems can allow clinicians to apply their experience and understanding of the situation to an individual but are not reproducible. Limitations relating to obtaining variables, calculating predicted mortality and applicability were present in most systems. Over time scoring systems have become out-dated which may reflect continuing improvement in care. APACHE II shows the importance of reproducibility and comparability particularly when assessing critically ill patients. Both NSQIP in the USA and P-POSSUM in the UK seem to have many benefits which derive from their comprehensive dataset. The "Surgical Apgar" score offers relatively objective criteria which contrasts against the subjective nature of the ASA score.

CONCLUSION

P-POSSUM and NSQIP are comprehensive but are difficult to calculate. In the search for a simple and easy to calculate score, the "Surgical Apgar" score may be a potential answer. However, more studies need to be performed before it becomes as widely taken up as APACHE II, NSQIP and P-POSSUM.

Anesthetic Considerations in the Patient With Valvular Heart Disease Undergoing Noncardiac Surgery

Valvular heart disease can be an important finding in patients presenting for noncardiac surgery. Valvular heart disease and resulting comorbidity, such as heart failure or atrial fibrillation, significantly increase the risk for perioperative adverse events. Appropriate preoperative assessment, adequate perioperative monitoring, and early intervention, should hemodynamic disturbances occur, may help prevent adverse events and improve patient outcome. This review article aims to guide the practitioner in the various aspects of anesthetic management in the perioperative care of patients with valvular heart disease. The pharmacological approach to optimization of patient outcome with drugs, such as βblockers and lipid-lowering medications (statins), is an evolving field, and recent developments are discussed in this article.

Value of myocardial viability estimation using dobutamine stress echocardiography in assessing risk preoperatively before noncardiac vascular surgery in patients with left ventricular ejection fraction <35%

Patients with heart failure (HF) scheduled for vascular surgery have an increased risk of adverse postoperative outcome, and stratification usually depends on dichotomous risk factors. A quantitative prognostic model for patients with HF was developed using wall motion patterns during dobutamine stress echocardiography (DSE). A total of 295 consecutive patients (mean age 67 +/- 12 years) with ejection fraction < or =35% were studied. During DSE, wall motion patterns of dysfunctional segments were scored as scar, ischemia, or sustained improvement. Cardiac death and myocardial infarction were noted perioperatively and during 5 years of follow-up. Of 4,572 dysfunctional segments; 1,783 (39%) had ischemia, 1,280 (28%) had sustained improvement, and 1,509 (33%) had scar. In 212 patients, > or =1 ischemic segment was present; 83 had only sustained improvement. Perioperative and late cardiac event rates were 20% and 30%, respectively. Using multivariate analysis, number of ischemic segments was associated with perioperative cardiac events (odds ratio per segment 1.6, 95% confidence interval 1.05 to 1.8), whereas number of segments with sustained improvement was associated with improved outcome (odds ratio per segment 0.2, 95% confidence interval 0.04 to 0.7). Multivariate independent predictors of late cardiac events were age and ischemia. Sustained improvement was associated with improved survival. In conclusion, DSE provides accurate risk stratification of patients with HF undergoing vascular surgery.

Mitral regurgitation complicates postoperative outcome of noncardiac surgery

BACKGROUND

Whether and how mitral regurgitation impacts perioperative outcome of noncardiac surgery remains unclear.

METHODS

From November 1999 to August 2004, all patients undergoing noncardiac operations and ever examined by echocardiography within prior 12 months were screened. Those with moderate-severe or severe mitral regurgitation were enrolled provided they were not already trachea-intubated and the surgery was not performed under local anesthesia. The perioperative outcomes of these patients were analyzed, and related prognostic predictors were investigated by multivariate logistic regression analysis.

RESULTS

A total of 84 patients (43 men, mean age of 66 years, low surgical risk in 28 and intermediate in 56) complying with the inclusion criteria were included. Their surgery was complicated by frequent (31%) yet minor intraoperative adverse events of controllable hypotension and bradycardia. In contrast, the postoperative outcomes were seriously complicated with high morbidity (27.4%, mostly pulmonary edema and prolonged tracheal intubation) and mortality (11.9%). Atrial fibrillation was identified by multivariate logistic regression analysis as the predictor of inhospital death (OD 11.579, P = .003), whereas surgical risk level (OD 5.118, P = .021), left ventricular ejection fraction (OD 0.958, P = .026), and atrial fibrillation (OD 3.058, P = .045), as independent predictors of postoperative morbidity.

CONCLUSIONS

Under current anesthetic management, patients with advanced mitral regurgitation could go through fairly safe intraoperative course of noncardiac surgery despite minor complications. Their postoperative outcome was, however, complicated by extraordinarily high morbidity and mortality, especially in those with preexisting atrial fibrillation, higher surgical risk level, and lower left ventricular ejection fraction.

B-type natriuretic peptide predicts cardiac morbidity and mortality after major surgery

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 &lt; 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 &lt; 0·001). BNP concentration remained a significant outcome predictor in multivariable analysis (P &lt; 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.

Risk Scoring in Perioperative and Surgical Intensive Care Patients: A Review

PURPOSE

Assessing the risk and predicting the outcome of surgery, trauma, and surgical intensive care is an important aspect of perioperative practice. There have been attempts to devise and validate many scoring systems to predict the prognosis of patients having a similar severity of illness. This article reviews some of the commonly used systems with respect to their development, strengths, and limitations.

SOURCES

Published literature describing risk assessment scores and physiologic scoring systems for preoperative assessment, trauma, and surgical intensive care patients.

PRINCIPAL FINDINGS

Risk scores used in preoperative evaluation assist the clinician in optimizing the patient before, during, and after surgery. Scoring systems applied in intensive care units are useful as guidelines rather than accurate predictors of prognosis for individual patient. Many models are used for audit purposes, and some are used as performance measures and quality indicators of a unit; however, both utilities are controversial because of poor adjustment of these systems to case-mixtures.

CONCLUSIONS

Risk assessment scores may assist in the perioperative risk evaluation with respect to organ systems. Prognostication of critically ill patients belonging to a category of illness may be done using physiological scoring systems taking into account the difference in the case-mix of the particular unit.

Preoperative Evaluation: Pulmonary, Cardiac, Renal Dysfunction and Comorbidities

This article reviews evidence supporting the exercise of risk assessment and demonstrates how it assists in determining which patients should undergo a planned invasive procedure. The article focuses on the preoperative functional assessment of three major organ systems--cardiac, pulmonary, and renal--and reviews guide-lines for determining which patients need additional testing of organ system function. The article also discusses how to improve the condition of selected patients so that the surgeon can achieve the best possible result and outcome.

Preoperative and Perioperative Care for Patients With Suspected or Established Aortic Stenosis Facing Noncardiac Surgery

Current medicine has displayed a trend toward less interfering techniques but more invasive surgical approaches in older patients with more comorbidities. In this population, the prevalence of symptomatic cardiac disease including aortic stenosis is increased. More than 25 years have elapsed since severe aortic stenosis was identified as an independent, important risk factor for patients undergoing general anesthesia for noncardiac surgery. Despite impressive advances in anesthesiologic and surgical techniques, morbidity and mortality in patients with severe aortic stenosis remains high. Published study results clearly show that adverse perioperative risk in patients with aortic stenosis depends on the interaction of factors such as the severity of valve disease, concomitant coronary artery disease, and the severity and/or urgency of the surgical procedures. The mainstay of preoperative evaluation remains the obtaining of a comprehensive preoperative medical history and a physical examination, while transthoracic echocardiography is necessary to establish or exclude hemodynamically relevant aortic stenosis in selected patients. Perioperative care is established in patients with asymptomatic aortic stenosis and/or those undergoing low-risk surgery. However, further preoperative testing or aortic valve replacement prior to noncardiac surgery should be discussed individually with the patients awaiting urgent surgical procedures who are at medium or high risk. At this point, decisions should be made in an interdisciplinary manner, including the opinions/wishes of the patient and the patient's family.

How is risk defined in high-risk surgical patient management?

The definition of risk in surgical patients is a complex and controversial area. Generally risk is poorly understood and depends on past individual and professional perception, and societal norms. In medical use the situation is further complicated by practical considerations of the ease with which risk can be measured; and this seems to have driven much risk assessment work, with a focus on objective measurements of cardiac function. The usefulness of risk assessment and the definition of risk is however in doubt because there are very few studies that have materially altered patient outcome based on information gained by risk assessment. This paper discusses these issues, highlights areas where more research could usefully be performed, and by defining limits for high surgical risk, suggests a practical approach to the assessment of risk using risk assessment tools.

Routine Measurement of Radioisotope Left Ventricular Ejection Fraction Prior to Vascular Surgery: Is it Worthwhile?

OBJECTIVE

To determine whether estimation of left ventricular (LV) ejection fraction (EF) by means of multiple gated acquisition (MUGA) scanning could reliably stratify cardiac risk prior to elective major vascular surgery.

METHODS

A review of the English-language literature.

RESULTS AND CONCLUSIONS

Twenty-two studies enrolling a total of 3096 patients were identified from 1984 to date. Selection bias, blinding of the results, different cut-off limits, and several retrospective studies were some of the problems preventing a comprehensive analysis. The resting LVEF was not found to be a consistent predictor of perioperative ischaemic cardiac events. In the perioperative phase, poor LV function was, mainly, predictive of congestive heart failure, and, in the long-term, of cardiac outcome. The presence of myocardial wall motion abnormalities was also associated with both a higher chance of postoperative cardiac complications and a worse long-term cardiac outcome. Although measurements of LV function seem to play a key role in defining a patient's long-term prognosis, the value of routinely measuring LVEF preoperatively is limited and, therefore, MUGA scanning cannot be recommended as a general screening test. Despite this, it has been widely used for cardiac risk assessment in vascular surgery, and only recently its popularity has started declining. Other tests, such as stress-echocardiography and myocardial perfusion imaging, used selectively in moderate-risk patients can refine prediction of cardiac risk. In the future, gated stress myocardial perfusion scintigraphy, perhaps combined with ANP/BNP plasma level determination, may become a first choice test in preoperative cardiac risk assessment.

Aortic stenosis: an underestimated risk factor for perioperative complications in patients undergoing noncardiac surgery

PURPOSE

To determine the incidence of perioperative events in patients with aortic stenosis undergoing noncardiac surgery.

METHODS

We studied 108 patients with moderate (mean gradient, 25 to 49 mm Hg) or severe (mean gradient, > or =50 mm Hg) aortic stenosis and 216 controls who underwent noncardiac surgery between 1991 and 2000 at Erasmus Medical Center. Controls were selected based on calendar year and type of surgery. Details of clinical risk factors, type of surgery, and perioperative management were retrieved from medical records. The main outcome measure was the composite of perioperative mortality and nonfatal myocardial infarction.

RESULTS

There was a significantly higher incidence of the composite endpoint in patients with aortic stenosis than in patients without aortic stenosis (14% [15/108] vs. 2% [4/216], P <0.001). This rate of perioperative complications was also substantially higher in patients with severe aortic stenosis compared with patients with moderate aortic stenosis (31% [5/16] vs. 11% [10/92], P = 0.04). After adjusting for cardiac risk factors, aortic stenosis remained a strong predictor of the composite endpoint (odds ratio = 5.2; 95% confidence interval: 1.6 to 17.0).

CONCLUSION

Aortic stenosis is a risk factor for perioperative mortality and nonfatal myocardial infarction, and the severity of aortic stenosis is highly predictive of these complications.

Association between cardiac and noncardiac complications in patients undergoing noncardiac surgery: outcomes and effects on length of stay

PURPOSE

To determine the relation between cardiac and noncardiac complications and their effects on length of stay in patients undergoing noncardiac surgery.

METHODS

We collected detailed information from the history, physical examination, and preoperative tests of 3970 patients aged > or =50 years who were undergoing major noncardiac procedures. Serial electrocardiograms and cardiac enzyme measurements were performed perioperatively, and cardiac and noncardiac complications were recorded prospectively. Multivariate logistic regression analysis was used to determine the association between cardiac and noncardiac complications, and linear regression was used to assess their effects on length of stay.

RESULTS

Cardiac complications occurred in 84 patients (2%), and noncardiac complications developed in 510 patients (13%). Both types of complications occurred in 40 patients (1%). The most common cardiac complications were pulmonary edema (n = 42) and myocardial infarction (n = 41). The most common noncardiac complications were wound infection (n = 291), confusion (n = 87), respiratory failure requiring intubation (n = 62), deep venous thrombosis (n = 48), and bacterial pneumonia (n = 46). Patients with cardiac complications were more likely to suffer a noncardiac complication than were those without cardiac complications, even after adjustment for preoperative clinical factors (odds ratio = 6.4; 95% confidence interval [CI]: 3.9 to 10.6). Mean length of stay was markedly increased in patients who experienced cardiac (11 days; 95% CI: 9 to 12 days) or noncardiac (11 days; 95% CI: 10 to 12 days) complications, or both (15 days; 95% CI: 12 to 18 days), as compared with patients without complications (4 days; 95% CI: 3 to 4 days), even after adjustment for procedure type and clinical factors.

CONCLUSION

Cardiac and noncardiac complications were strongly linked in patients undergoing noncardiac surgery. Patients who experienced one type of complication were at increased risk of developing the other type of complication as well as prolonged perioperative length of stay.