Publication Date

2019

Abstract

Suboptimal post‐operative improvements in functional capacity are often observed after minimally invasive aortic valve replacement (mini‐AVR). It remains to be studied how AVR affects the cardiopulmonary and skeletal muscle function during exercise to explain these clinical observations and to provide a basis for improved/tailored post‐operative rehabilitation. Twenty‐two patients with severe aortic stenosis (AS) (aortic valve area (AVA) <1.0 cm²) were pre‐operatively compared to 22 healthy controls during submaximal constant‐workload endurance‐type exercise for oxygen uptake (urn:x-wiley:09580670:media:eph12495:eph12495-math-0001), carbon dioxide output (urn:x-wiley:09580670:media:eph12495:eph12495-math-0002), respiratory gas exchange ratio, expiratory volume (urn:x-wiley:09580670:media:eph12495:eph12495-math-0003), ventilatory equivalents for O2 (urn:x-wiley:09580670:media:eph12495:eph12495-math-0004/urn:x-wiley:09580670:media:eph12495:eph12495-math-0005) and CO2 (urn:x-wiley:09580670:media:eph12495:eph12495-math-0006/urn:x-wiley:09580670:media:eph12495:eph12495-math-0007), respiratory rate (RR), tidal volume (Vt), heart rate (HR), oxygen pulse (urn:x-wiley:09580670:media:eph12495:eph12495-math-0008/HR), blood lactate, Borg ratings of perceived exertion (RPE) and exercise‐onset urn:x-wiley:09580670:media:eph12495:eph12495-math-0009 kinetics. These exercise tests were repeated at 5 and 21 days after AVR surgery (n = 14), along with echocardiographic examinations. Respiratory exchange ratio and ventilatory equivalents (urn:x-wiley:09580670:media:eph12495:eph12495-math-0010/urn:x-wiley:09580670:media:eph12495:eph12495-math-0011 and urn:x-wiley:09580670:media:eph12495:eph12495-math-0012/urn:x-wiley:09580670:media:eph12495:eph12495-math-0013) were significantly elevated, urn:x-wiley:09580670:media:eph12495:eph12495-math-0014 and urn:x-wiley:09580670:media:eph12495:eph12495-math-0015/HR were significantly lowered, and exercise‐onset urn:x-wiley:09580670:media:eph12495:eph12495-math-0016 kinetics were significantly slower in AS patients vs. healthy controls (P < 0.05). Although the AVA was restored by mini‐AVR in AS patients, urn:x-wiley:09580670:media:eph12495:eph12495-math-0017/urn:x-wiley:09580670:media:eph12495:eph12495-math-0018 and urn:x-wiley:09580670:media:eph12495:eph12495-math-0019/urn:x-wiley:09580670:media:eph12495:eph12495-math-0020 further worsened significantly within 5 days after surgery, accompanied by elevations in Borg RPE, urn:x-wiley:09580670:media:eph12495:eph12495-math-0021 and RR, and lowered Vt. At 21 days after mini‐AVR, exercise‐onset urn:x-wiley:09580670:media:eph12495:eph12495-math-0022 kinetics further slowed significantly (P < 0.05). A decline in pulmonary function was observed early after mini‐AVR surgery, which was followed by a decline in skeletal muscle function in the subsequent weeks of recovery. Therefore, a tailored rehabilitation programme should include training modalities for the respiratory and peripheral muscular system.

School/Institute

Mary MacKillop Institute for Health Research

Document Type

Journal Article

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