DISCUSSION
The accuracy of the COVID-19 diagnostic tests is still suboptimal, with a high percentage of false negatives on the PCR-RNA analysis from nasopharyngeal swab samples [9]. Also, there are cases where the individuals with a previous negative test, become positive again in subsequent tests without any associated clinical deterioration that would help in predicting this [10].
The ideal convalescence period after having tested positive for COVID-19 it is also unknown, especially in the absence of symptoms or abnormalities in the chest imaging modalities.
We know from previous reports out of China [3, 4] and our own experience, that patients who develop COVID-19 during the immediate postoperative period, regardless of the nature of the surgical procedure, have a bad prognosis, with high mortality and morbidity related to respiratory complications.
In the current era, when all the elective surgical procedures have been paused to prioritise intensive care resources to accommodate the COVID-19 patients, we have concentrated in treating urgent and emergency cardiac and aortic surgery cases. We have established a rigorous COVID-19 screening protocol following international recommendations, including the combination of questionnaire for COVID-19-related symptoms, two negative nasopharyngeal swabs, clear lung fields on a non-contrasted CT chest and the absence of lymphopenia or excessively elevated LDH levels [5].
In emergency cases there is no option to wait for the swab results, hence the surgical indication outweighs the risk of COVID-19 infection especially in the patients with no COVID-19-related symptoms and pulmonary infiltrates on the CT chest.
However, in the urgent cases, with at least 24 - 48 hours margin to wait for the screening results, we are now facing a proportion of patients who are COVID-19 positive with mild symptoms or even not symptomatic at all. Despite that, all patients are treated as if they were positive and all the universal PPE precautions taken [5].
To date there is little knowledge of the predictors to determine the earliest safe time to plan an operation, in patients who may still be infectious and/or with potential for reactivation in the immediate postoperative period, with potential catastrophic consequences for their respiratory system after having been exposed to the cardiopulmonary bypass with the subsequent systemic inflammatory response.
For this reason, we believe it is important to manage each case individually, and when time permitting, to wait until the viral load and the radiological infiltrates (if any) have resolved.
In our experience, the close monitoring in a hospital environment, where the patients were kept in isolation and only interacting with full-PPE equipped healthcare professionals, allowed us to postpone the urgent surgery until they became COVID-19 negative. With those measures in place, we achieved a good outcome for all of them, without any COVID-19-related complications in the postoperative period and a 100% survival rate.
Further studies on a larger volume of patients, like the CovidSurg international multicentre study, will help to increase to understand the impact of COVID-19 during the peri-operative period and add some clarity and recommendations to the optimal timing for offering surgery in patients recovered from COVID-19.