Impact of blood pressure on coronary perfusion and valvular hemodynamics after aortic valve replacement

Abstract

Objective: Our objective was to evaluate the impact of various blood pressures (BPs) on coronary perfusion and valvular hemodynamics following aortic valve replacement (AVR).Background: Lower systolic and diastolic (SBP/DBP) pressures from the recommended optimal target range of SBP < 120-130 mmHg and DBP < 80 mmHg after AVR have been independently associated with increased cardiovascular and all-cause mortality. Methods:The hemodynamic assessment of a 26 mm SAPIEN 3 transcatheter aortic valve (TAV), 29 mm Evolut R TAV, and 25 mm Magna Ease surgical aortic valve (SAV) was performed in a pulsed left heart simulator with varying SBP, DBP, and heart rate (HR) conditions (60 and 120 bpm) at 5 L/min cardiac output (CO). Average coronary flow (CF), effective orifice areas (EOAs), and valvulo-arterial impedance (Zva) were calculated.Results: At HR of 60 bpm, at SBP < 120 mmHg and DBP < 60 mmHg, CF decreased below the physiological lower limit with several different valves. Zva and EOA were found to increase and decrease respectively with increasing SBP and DBP. The same results were found with an HR of 120 bpm. The trends of CF variation with BP were similar in all valves however the drop below the lower physiological CF limit was valve dependent. Conclusion:In a controlled in vitro system, with different aortic valve prostheses in place, CF decreased below the physiologic minimum when SBP and DBP were in the range targeted by blood pressure guidelines. Combined with recent observations from patients treated with AVR, these findings underscore the need for additional studies to identify the optimal BP in patients treated with AVR for AS.

Differential Impact of Blood Pressure Control Targets on Epicardial Coronary Flow After Transcatheter Aortic Valve Replacement

“…Average ECF was between 58.8 and 73.5 ml/min, which is the physiological range for the RCA to achieve 70% of 4% to 5% of the total cardiac output. 15 , 19 The ECF was set within these physiological limits at 130/80 mmHg by setting the resistance of the coronary circuit at the beginning of the experiment. Then, once the baseline coronary conditions have been achieved, the coronary circuit parameters are held fixed as the systemic BPs are varied to evaluate the sole impact of aortic BP on the resulting coronary flow.…”

“…In a previous study, 15 we experimentally assessed the effect of SBP and DBP independently on epicardial coronary flow (ECF) variation and valve hemodynamics. We found that ECF decreased below the physiological minimum when BPs were in the recommended range.…”