A reply

We thank Dr Morris for her comments on our article. We agree with her that antibiotic prophylaxis against bacterial endocarditis for certain types of procedures is recommended in patients with valvular heart disease (VHD). However, we do not agree that all patients' chests should be auscultated before surgery. Firstly, pre-operative evaluation aims to discover potential comorbidity that, if left unattended or untreated, may harm patients during and after surgery [1]. Second, pre-operative evaluation should be targeted to detect comorbidity that is relevant for the peri-operative period, rather than being a complete ‘health check’ with recommendations for follow-up [1]. With the increasing popularity of performing pre-operative evaluation some weeks before surgery, thousands of patients are now screened routinely by anaesthetists [2]. That necessitates the development of evidenced-based guidelines for anaesthetic pre-operative evaluation rather than performing pre-operative evaluation based on case histories and personal opinions [1, 3–5]. This development of guidelines can be performed using methodology from prognostic and diagnostic research, such as in our study. The probability of finding a rare disease (like significant VHD in a young patient) during screening of large populations is influenced by the prevalence of that disease in the underlying population and by the accuracy of the screening instrument (the anaesthetist listening to heart sounds). We showed that, with the current screening methods, the prevalence of VHD in surgical patients under 40 years is very low; we did not find a single case in 696 patients. Therefore, we argued that it may be unnecessary to perform auscultation in this group of young patients and that it may be more important to pay attention to elderly patients, in which the prevalence of VHD is much higher resulting in a higher probability of detection. Otherwise, an echocardiogram should be performed in each patient with a murmur to rule out VHD, even in patients under 40 years. This may delay surgery in most of these patients unnecessarily. Another option may be to administer antibiotic prophylaxis to each patient with a murmur, unnecessarily exposing many young patients to the risks of antibiotic related adverse events. In conclusion, weighing the benefits and risks of referring all patients with a murmur for echocardiography or administering prophylactic antibiotics to them all without referring them, we still think it is reasonable to perform cardiac auscultation in patients aged over 40 years only.