Serial measurements of peripheral vascular reactivity and exercise capacity in congestive heart failure and after heart transplantation

BACKGROUND: The regulation of nutritive blood flow to skeletal muscles during exercise seems to make an important contribution to exercise capacity. In congestive heart failure (CHF) this regulation seems to be impaired, with attenuated peripheral vasodilatory capacity. The results regarding improvement of peripheral vasoreactivity after heart transplantation (HTx) are conflicting, and the contribution of impaired peripheral vasoreactivity to the observed reduced exercise capacity among heart transplant recipients (HTR) has not been well elucidated. We therefore assessed the reversibility of impaired vasoreactivity in forearm and calf after HTx with relationship to exercise capacity. METHODS AND RESULTS: The vasoreactivity of both forearm and calf was studied with venous occlusion plethysmography and related to exercise capacity in 64 patients with CHF and in 22 controls. Of these patients, 29 patients underwent HTx, and the same measurements were performed 10 days, 6 months and 1 year after HTx, and in a group of 15 HTR who had undergone HTx several years ago. Our main findings were (1) impaired resting blood flow in patients with CHF improved after HTx and even surpassed levels of controls; (2) peak forearm blood flow remained attenuated early after HTx, but normalized during the first year postoperatively; (3) both forearm and calf minimal resistance remained elevated after HTx; (4) vascular reactivity displays regional variations in forearm and calf both during CHF and after HTx; and (5) peripheral vascular reactivity relate to exercise performance in both patients with CHF and HTR, but the relationship seemed more pronounced in CHF. CONCLUSION: With impaired vasoreactivity related to limited exercise capacity in CHF, improvement is evident after HTx, but both forearm and calf minimal resistance remains elevated. These findings suggest increased vasoconstrictor drive to both exercising and non-exercising muscles, possibly contributing to persistent physical limitation after HTx.