Are techniques for general anesthesia less invasive than procedures for cataract surgery?

Sir,

We read with special interest the retrospective cohort study by Alboim et al¹ who examined the importance of preoperative evaluation for outpatients undergoing cataract surgery. They suggested that preoperative evaluation has no role in reducing adverse events in these patients. On the other hand, their study showed that 36 in 240 preoperatively evaluated patients were managed for optimization before surgery, where reversal for anticoagulation was done for 18.7% patients. In twelve emergency hospital visits after surgery, one adverse event concerning anticoagulation was included.

Because of the minimum invasiveness of cataract surgery, a consensus that direct oral anticoagulants (DOACs) as well as vitamin K antagonists (VKAs) should be continued around the time of the procedure is steadily growing.² Clinically available blood-test monitoring cannot exactly measure the anticoagulation functions of DOACs.³ This is also leading to a practical trend that DOACs can be used without the need for routine monitoring. We have recently surveyed 728 sequential clinical records of patients undergoing cataract surgery in our hospital after the approval of the institutional review board. We found that DOACs were prescribed to 12 patients, while only one patient with dabigatran was preoperatively evaluated for coagulopathy. Out of 42 patients taking warfarin 23 were not monitored with PT-INR. It is noteworthy that PT or APTT longer than normal limits in patients taking DOACs is a sign of the overdosing of DOACs.³ PT-INR> 3 in patents with VKAs also points to abnormal bleeding.^{2, 4}

In this context, we think of a scenario where an anesthetic plan for outpatient cataract surgery was unexpectedly changed from local to general anesthesia. If this patient had taken DOACs several hours before the surgery, the risk of hematoma in the upper airway caused by laryngoscopy should be increased.⁴ If the patient had renal dysfunction, this risk should be more increased.³ If this patient had taken VKAs for several days before surgery, but not monitored with PT-INR, such risk should also be increased. Considering such a scenario, we recommend to monitor coagulation functions before cataract surgery when omitting the preoperative evaluation.