We are more than happy to answer the questions Schulthess et al.1 have, based on our previous publication.2 The first question was to provide baseline characteristics of patients with and without myocardial injury. Their second question was related to the exposure and the associated risk for myocardial injury. Schulthess et al. are correct that duration under a mean arterial pressure (MAP) threshold of 75 mmHg is only associated with myocardial injury for prolonged periods of time. To graphically represent the relation between length of hypotension and myocardial injury, we could have chosen a MAP target of 60 mmHg where all durations, above 1 h, show an increased risk for myocardial injury. However, we have specifically chosen to report the highest threshold because this threshold was selected based on the figure in the supplemental digital content of the original article. Furthermore, we believe this threshold is relevant because the amount of time that was associated with myocardial injury (greater than 10 h) can be easily reached during the first postoperative night. The final question was with regard to certain preoperative medication and the risk of confounding. In our analysis we used the widely accepted rule of 10 events per variable to prevent imprecise and biased estimates in the logistic regression analysis. We therefore chose to adjust for the variables mostly associated with myocardial injury or hypotension. Sensitivity analysis including adjustment for the preoperative cardiovascular medication showed marginal differences in our results. Please find all the requested analysis in the tables 1–3.
The authors declare no competing interests.