The worsening of cardiac function by the repeated micro-embolization attenuates the very short-term blood pressure lability index in dogs

Abstract

Background: Recently, we developed a novel method for the assessment of very short-term blood pressure lability (BLI). BLI is calculated from the integrated area of blood pressure (BP) power spectral density from 0.01 Hz to 0.1 Hz. Given that low cardiac function suppresses blood pressure (BP) variation, we investigated how the worsening of cardiac function can be reflected in BLI by using a dog model of heart failure with reduced ejection fraction (HFrEF). Methods: In 6 dogs, chronic heart failure was induced through the use of multiple sequential microembolization via bolus injection of polyester microspheres (90μm) into the left descending or circumflex coronary arteries. We repeated coronary microembolization every two weeks and checked the arterial pressure, left ventricular pressure, and echocardiogram under general anesthesia in every session. BLI was calculated from the continuous BP recording by the catheter placed at ascending aorta before micro-embolization. We examined the changes of cardiac function and BLI, and compared them among the sessions of microembolization. Results: In every dog, the repeated microembolization significantly reduced left ventricular ejection fraction (Baseline: 66±4 vs. HF: 38±6, %, P<0.01) and increased left ventricular end diastolic volume (Baseline: 23±4 vs. HF: 36±4, ml, P<0.01), indicating the worsening of cardiac function and remodeling. Although the mean BP did not change significantly, the BLI were significantly lower in heart failure condition (6±2 times microembolization) compared to baseline (Baseline: 0.7±0.2 vs. HF: 0.4±0.1, mmHg, P<0.05). Conclusions: Our findings demonstrate that the BLI in a HFrEF model dog was lower than that in baseline condition with normal hemodynamics. The BLI showed the potential for the assessment of the cardiac function and hemodynamic severity in HFrEF. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.