This single-center, retrospective observational study was approved by the Ethics Committee of the Hirosaki University Graduate School of Medicine, Hirosaki, Japan and was published on our department and hospital homepage (2022–063). The requirement for written informed consent from each patient was waived because of the retrospective nature of the study, and the Ethics Committee approved the waiver.

We included 163 patients who underwent TAVI at Hirosaki University Hospital between November 5, 2019 and August 9, 2022. Patients who underwent TAVI with monitored anesthesia care (MAC) were excluded.

PIH was defined as at least one measurement of systolic arterial pressure (SAP) <90 mmHg or at least one incident of norepinephrine infusion at a rate >6 µg/min from anesthetic induction until 20 min post-induction, which is same as a previous study [5].

Patients with PIH were assigned to the PIH group and those without PIH were assigned to the non-PIH group.

The following data were obtained from the medical and anesthesia records: age, sex, body mass index, ASA-PS, New York Heart Association (NYHA) functional class, Society of Thoracic Surgeons (STS) risk score, past medical history, type of antihypertensive agents, cardiac echocardiogram data, amount of anesthetics for induction, amount of vasopressor use, heart rate (HR) (pre-induction, minimum from induction of general anesthesia until 20 min post-induction), duration of anesthesia and surgery, amount of intraoperative blood loss, amount of intraoperative urine output, amount of intraoperative fluid infusion, length of intensive care unit (ICU) stay, and length of hospital stay.

All patients were premedicated with 75 mg roxatidine acetate hydrochloride. All antihypertensive agents were continued on the day of the surgery. A radial arterial line was placed prior to anesthetic induction in all cases. The choice of anesthetic was not standardized and was performed by an anesthesiologist. For anesthetic induction, we used a combination of propofol or remimazolam, remifentanil, and/or fentanyl, with or without ketamine and rocuronium. For maintenance anesthesia, we used a combination of propofol or remimazolam, remifentanil, and/or fentanyl, with or without ketamine and rocuronium, or a combination of desflurane and remifentanil with/without fentanyl and rocuronium.

The patients’ characteristic data, intraoperative data, and postoperative outcomes were presented as the median (25th to 75th percentile) and the number (percentage of each group). Statistical differences between the two groups were assessed using Fisher’s exact test for categorical variables and the Mann–Whitney U test for continuous variables.

We performed a multivariable logistic regression analysis to develop a predictive model for PIH in patients undergoing TAVI. To estimate the optimal cutoff value of continuous variables for predicting the development of PIH in multivariate logistic regression analyses, a receiver operating characteristic (ROC) curve analysis was conducted for each continuous variable. The STS risk score was adjusted for age, sex, comorbidities, and cardiac function. Baseline blood pressure, age, ASA-PS, and the presence of type II diabetes mellitus have been reported to be associated with a higher risk of developing PIH [4,5,6]. However, as age and the presence of type II diabetes mellitus were used to calculate STS risk scores, these variables were not included. Additionally, ASA-PS was also not included because 96.3% of patients in the study were ASA-PS 3. Therefore, only the baseline blood pressure was included. A mean pressure gradient of ≥60 mmHg is reported to be associated with an increased risk of severe AS [8] and was included in the definition of very severe AS [9]. Thus, as a mean pressure gradient of ≥60 mmHg may be associated with PIH, it was also included. The type and amount of anesthesia used for induction were also included. The variance inflation factor (VIF) was used to check for multicollinearity among the variables. Discrimination was measured using the area under the curve (AUC). The results are expressed as adjusted odds ratios (aORs) with corresponding 95% confidence intervals (CIs).

Additionally, we performed Kaplan–Meier curve analysis with the log-rank test to investigate the effect of PIH on the length of hospital stay, and we compared the probability of hospital stay between the PIH and non-PIH groups.

All data analyses were performed using EZR software ver. 1.61 (Saitama Medical Center, Jichi Medical University, Saitama, Japan). Statistical significance was set at p < 0.05.