How high risk are 'high-risk' surgical patients?

Introduction

Preoperative optimization of 'high-risk' elective surgical patients has been demonstrated to result in improved outcomes. However, it has been argued that the mortality in the control groups was higher than expected, given the inclusion criteria. There have been no previous systematic studies of the outcome of patients who meet 'high-risk' criteria.

Method

A retrospective cohort study involving case reviews of all adult (> 18 years) patients undergoing elective major general or vascular surgery in a tertiary referral university teaching hospital during the year 2001. No patients were admitted to the ICU for preoperative optimization. Hospital mortality, age, duration of surgery and the presence or absence of the following risk factors was recorded: extensive ablative abdominal surgery for cancer, congestive cardiac failure, ischaemic heart disease, cardiac arrhythmia, hypertension, chronic obstructive pulmonary disease, pulmonary embolus, chronic renal insufficiency, diabetes mellitus with end-organ damage, long-term steroid therapy, chronic liver disease, cerebrovascular accident and peripheral vascular disease.

Results

Data was available from 727 of 874 patients undergoing major general or vascular surgery. Of these, 450 underwent an operation lasting 2 hours or more. Only data from these 450 patients was analysed. The average age was 61 years and 48% of the patients were male. Overall hospital mortality was 3.8%. Hospital mortality in patients with one or more risk factors was 5.4%. The mortality associated with the presence of one or more risk factors is presented in Table 1.

Table 1

Conclusions

The hospital mortality of 'high-risk' surgical patients undergoing elective surgery may not be as high as the control group mortality (17–50%) of previous randomized controlled trials [1, 2]. As a result, the reduction in mortality demonstrated in these studies may be an overestimate of the reduction that will be achieved if preoptimization is provided for all 'high-risk' surgical patients undergoing elective surgery.