Key result
Wearable ultrasound of carotid corrected flow time detects significant stroke volume increases with 0.89 AUC.
Why the study?
Change in carotid artery corrected flow time is a surrogate for stroke volume change, but its optimal threshold and accuracy to detect preload responsiveness remain inconsistent.
Does change in carotid artery corrected flow time measured by a wearable Doppler ultrasound accurately detect stroke volume change in adult patients after elective CABG?
Observational (n=30)
No
Does change in carotid artery corrected flow time measured by a wearable Doppler ultrasound accurately detect stroke volume change in adult patients after elective CABG?
Effect estimate: r = 0.70
p-value: p=<.001
A wireless, wearable Doppler ultrasound measuring carotid artery corrected flow time accurately detects stroke volume changes in post-CABG patients, offering a non-invasive tool to guide postoperative fluid therapy.
May support noninvasive SV monitoring post-CABG; leaves open prospective validation before practice change.
Background: As a measure of preload responsiveness (PR), change in carotid artery corrected flow time (ccFTΔ) is a surrogate for change in stroke volume (SVΔ). However, the optimal threshold and accuracy of ccFTΔ to detect SVΔ are inconsistent in previous reports. Research Question: Does ccFTΔ from a wireless, wearable Doppler ultrasound accurately detect a 10% SVΔ measured by transesophageal echocardiography? Study Design and Methods: This was a prospective, single-center study of adult patients after elective coronary artery bypass grafting. PR was defined as ≥ 10% augmentation in transesophageal echocardiography left ventricular outflow tract velocity time integral (as a surrogate for SVΔ) during Trendelenburg positioning. Synchronous carotid Doppler imaging was captured by a wireless, wearable Doppler ultrasound. The optimal ccFTΔ threshold to detect PR, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated. Linear correlation between ccFTΔ and SVΔ was assessed by Pearson correlation coefficient. We also evaluated the effect of the number of consecutively averaged cardiac cycles on ccFTΔ accuracy. Results: This analysis included 30 patients; 7 patients showed a ≥ 10% SVΔ during Trendelenburg positioning. The optimal ccFTΔ thresholds were +6.6 ms or 2.2% with sensitivities of 100%, specificities of 70%, and AUCs of 0.89 and 0.88, respectively. A strong, linear correlation between ccFTΔ and SVΔ was found (r = 0.70; P < .001). The mean AUC increased from 0.68 to 0.87 when using 1 vs 20 consecutively averaged cardiac cycles. Interpretation: After cardiopulmonary bypass, ccFTΔ measured by wireless, wearable ultrasound detected SVΔ during Trendelenburg positioning with high accuracy. The AUC improved as a function of consecutively averaged cardiac cycles. As a surrogate for preload-induced SVΔ, ccFTΔ can direct fluid therapy in the postoperative period.
No takes yet. Share an insight, caveat, or question.
Kenny et al. (2025) conducted an observational in Post-elective coronary artery bypass grafting (n=30). Carotid artery corrected flow time (ccFTΔ) measured by wireless, wearable Doppler ultrasound vs. Stroke volume change (SVΔ) measured by transesophageal echocardiography was evaluated on Detection of ≥ 10% stroke volume change (SVΔ) during Trendelenburg positioning (r = 0.70, p=<.001). Carotid artery corrected flow time change measured by wearable ultrasound strongly correlated with stroke volume change (r=0.70, P<.001) and detected a ≥10% increase with an AUC of 0.89.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: