Predictors of ineffectual radial arterial pressure monitoring in valvular heart surgery

Background and aim of the study: Unexpected sustained underestimation of the central aortic pressureby the radial arterial pressure commonly develops following cardiopulmonary bypass (CPB) in valvularheart surgery (VHS), leading to an inappropriate use of vasopressors. The study aim was to identify clinical predictors leading to a sustained inappropriate difference between the radial and femoral arterial pressure (IDRF) in VHS. Methods: A total of 200 patients undergoing VHS was studied prospectively. Those patients who developed sustained IDRF (systolic IDRF ≥ mmHg and/or mean IDRF ≥5 mmHg) from immediately after discontinuation of CPB until the end of the surgery were compared with patients who did not develop any IDRF. Results: Data from seven patients who required second aortic cross-clamping and re-CPB were excluded from the analysis; thus, data from 193 patients were analyzed. In total, 53 patients (27.5%) developed sustained IDRF, whereas 80 patients (41.4%) did not develop any IDRF. In multivariate analysis, female gender, the presence of atrial fibrillation and diuretic use were identified as independent preoperative predictors; longer-duration aortic cross-clamping and use of larger amounts of vasopressin during CPB were identified as independent operative risk factors of the sustained IDRF. Conclusion: When an erroneously low radial arterial pressure is suspected following CPB in this subset of patients undergoing VHS, monitoring of the femoral or axillary arterial pressure should be considered to guide hemodynamic management, as there is an increased risk of persistence of this phenomenon.