Key result
Mean arterial pressure decreased by a median of 6 mmHg during head-up tilt in patients with coronary artery disease both before and after coronary artery bypass grafting, while remaining unchanged in healthy subjects.
Why the study?
Does coronary artery bypass grafting alter the blood pressure and hemodynamic response to head-up tilting in patients with coronary artery disease?
Observational (n=16)
No
Does coronary artery bypass grafting alter the blood pressure and hemodynamic response to head-up tilting in patients with coronary artery disease?
Absolute Event Rate: -6% vs 0%
p-value: p=0.008
CABG resolves the orthostatic decrease in stroke volume and cardiac output during head-up tilt, though blood pressure still decreases postoperatively likely due to fluid loss.
Blood pressure response to head-up tilt (HUT) in 7 healthy subjects and 9 patients before and after coronary artery bypass grafting (CABG) was measured during supine and 15-min 60° HUT. Stroke volume (SV) and ejection fraction (EF) were assessed by echocardiography. Baseline mean arterial pressure (MAP) and heart rate (HR) in patients before CABG were similar to healthy subjects. MAP in patients decreased by 6 (4-9) mmHg [median (1st-3rd quartiles)] during 7-12 mmHg of HUT with decreased cardiac output (CO = SV × HR) while HR remained unchanged. MAP in healthy subjects remained unchanged during HUT with increased HR. Body weight decreased by 3.5 (2.5-3.7) kg and MAP decreased by 6 (2-13) mmHg during the last 3-min HUT while HR increased after CABG. Decreases in SV and CO during HUT disappeared after CABG. Blood pressure decreased during HUT in patients before and after CABG regardless of HR response.
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Hori et al. (2020) conducted an observational in Coronary artery disease (n=16). Coronary artery bypass grafting (CABG) vs. Healthy subjects and pre-CABG baseline was evaluated on Change in mean arterial pressure (MAP) during 60° head-up tilt (p=0.008). Mean arterial pressure decreased by a median of 6 mmHg during head-up tilt in patients with coronary artery disease both before and after coronary artery bypass grafting, while remaining unchanged in healthy subjects.
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