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Grazioli et al commented on the utility of mean arterial pressure (MAP) to assess potential hemodynamic compromise. The authors mention that even brief and nonsustained periods of intraoperative decline in MAP are associated with acute kidney injury (AKI), as seen in the study of Walsh et al,1Walsh M. Devereaux P.J. Garg A.X. Kurz A. Turan A. Rodseth R.N. et al.Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery: toward an empirical definition of hypotension.Anesthesiology. 2013; 119: 507-515Crossref PubMed Scopus (855) Google Scholar in which a MAP <55 mm Hg had the strongest association with AKI. In our study, data on lowest intraoperative MAP were collected, and we did not find a significant association between lowest MAP (P = .118) and MAP <55 mm Hg (P = .085) and postoperative AKI. This should, however, be interpreted cautiously because our analysis had limited statistical power to detect an association (our cohort included 406 patients, whereas the study of Walsh et al included 27,381 patients). Another limitation could relate to the method of recording intraoperative hemodynamic data. Walsh et al used data from automated recording that collected MAP at 1- to 2-minute and 2- to 5-minute intervals. The participating centers in our study recorded blood pressure (BP) manually at 5-minute intervals. The data of Walsh et al had more granularity, allowing analysis. Furthermore, studies have shown that manually collected data tend to underestimate low BP compared with automated methods.2Lerou J.G. Dirksen R. van Daele M. Nijhuis G.M. Crul J.F. Automated charting of physiological variables in anesthesia: a quantitative comparison of automated versus handwritten anesthesia records.J Clin Monit. 1988; 4: 37-47Crossref PubMed Scopus (87) Google Scholar, 3Thrush D.N. Are automated anesthesia records better?.J Clin Anesth. 1992; 4: 386-389Abstract Full Text PDF PubMed Scopus (68) Google Scholar Acknowledging these limitations, the lack of a statistically significant association seen between a MAP <55 mm Hg and AKI in our results should not be interpreted as an absence of such an association but more likely represents a limitation of data availability. More important, despite these limitations, we found a strong association with the number of antihypertensive medications taken on the morning of surgery, but not with the number taken chronically. We put forward that the mechanisms by which antihypertensive medications increase the risk of AKI may be not solely by causing hypotension but also by blocking autoregulatory mechanisms. The authors also comment that hemodynamic change from baseline may be more important than the absolute drop in BP. Although this may be the case in hypertensive patients initiated on new antihypertensive therapy, this remains unclear in the perioperative setting. Futier et al4Futier E. Lefrant J.Y. Guinot P.G. Godet T. Lorne E. Cuvillon P. et al.Effect of individualized vs standard blood pressure management strategies on postoperative organ dysfunction among high-risk patients undergoing major surgery: a randomized clinical trial.JAMA. 2017; 318: 1346-1357Crossref PubMed Scopus (371) Google Scholar recently published the results of a randomized controlled trial of patients who underwent noncardiac surgery and were allocated to maintaining the systolic BP within 10% of baseline or standard of care. The occurrence of AKI did not differ significantly between groups (P = .086). Regarding the possibility of the number of antihypertensive medications being a surrogate for higher perioperative risk of AKI, we addressed this in our post hoc analyses and did not find an association between the number of chronic antihypertensive medications and postoperative AKI. We agree with the authors' conclusion that further studies are required to inform on the optimal management of antihypertensive therapies and intraoperative hemodynamic targets to reduce postoperative complications such as AKI. Considering the current data available on the adverse effects of intraoperative hypotension on renal outcomes and our results showing an increased risk of AKI associated with antihypertensive medications, we believe it reasonable to advise caution in continuing antihypertensive medications perioperatively until further prospective data are available. Regarding “Preoperative antihypertensive medication intake and acute kidney injury after major vascular surgery”Journal of Vascular SurgeryVol. 69Issue 2PreviewWe read with great interest the article entitled “Preoperative antihypertensive medication intake and acute kidney injury after major vascular surgery” in the June 2018 issue of Journal of Vascular Surgery. This retrospective study of 406 patients undergoing major vascular surgery finds that in chronically hypertensive patients, the number of antihypertensive drugs administered on the morning of surgery is independently associated with an increased risk of postoperative acute kidney injury (AKI). Full-Text PDF Open Archive