EXPRESS: Preoperative Corrected Carotid Flow Time Is Associated With Spinal Anesthesia-Induced Hypotension in Hypertensive Patients: A Prospective Observational Study

BACKGROUND: Spinal anesthesia-induced hypotension (SAIH) is common in hypertensive patients, yet reliable preoperative markers remain limited. Corrected carotid flow time (CCFT) is a Doppler-derived index influenced by preload and ventricular ejection timing, but its association with SAIH in this population has not been established. OBJECTIVE: To evaluate whether preoperative CCFT is independently associated with SAIH in hypertensive patients undergoing spinal anesthesia. DESIGN: Single-center prospective observational study. SETTING: University hospital, operating room. PATIENTS: 110 hypertensive adults scheduled for lower abdominal or lower extremity surgery under spinal anesthesia. INTERVENTIONS: Preoperative carotid and brachial ultrasound assessments (CCFT, carotid intima-media thickness [CIMT], flow-mediated dilation [FMD], carotid blood flow [CBF], and internal jugular vein collapsibility index [IJV-CI]) were performed. Hemodynamics were recorded for 30 minutes after spinal injection. MAIN OUTCOME MEASURES: Primary outcome: SAIH (≥20% decrease in systolic blood pressure or SBP <90 mmHg sustained for ≥1 minute). SECONDARY OUTCOMES: hemodynamic trends and discriminative performance of ultrasound parameters. RESULTS: SAIH occurred in 54 patients (49.1%). CCFT was shorter in patients who developed hypotension (326.5±71.3 vs. 437.3±82.9 ms, p<0.001). In the primary multivariable model including CIMT, FMD, and beta-blocker use, CCFT remained independently associated with SAIH (aOR 0.980 per 1-ms increase, 95% CI 0.973-0.988, p<0.001). CCFT alone had an AUC of 0.854 (95% CI 0.785-0.924); the 358.5-ms cut-off had 74.1% sensitivity and 87.5% specificity. A clinical model including age, baseline SBP, and beta-blocker use had an AUC of 0.572 (95% CI 0.465-0.679); adding CCFT increased the AUC to 0.866 (95% CI 0.799-0.932; paired comparison p<0.001). CONCLUSIONS: Preoperative CCFT was independently associated with SAIH and improved discrimination when added to a parsimonious clinical model. The cohort-derived threshold requires external validation before clinical implementation. TRIAL REGISTRATION: ClinicalTrials.gov (https://clinicaltrials.gov/), NCT06749184.