Study objective: The reduced exercise capacity observed
in most patients after heart transplantation may be due to treatment
with immunosuppressive drugs, deconditioning, cardiac denervation, and
graft rejection. Cardiac allograft vasculopathy (CAV) is presently the
major factor limiting long-term survival after transplantation. Little
information is available with regard to the relationship between CAV
and functional impairment in these patients.
Setting: A university hospital and a
large transplant center.
37 ± 5 months (range, 2 to 137 months) after orthotopic heart
transplantation, 120 patients underwent lung function testing,
cardiopulmonary exercise testing, and right and left heart
catheterization. Significant CAV was defined as a stenosis ≥ 70% or
severe diffuse obliteration in any of the three main vessels. Group I
(n = 28) had a significant CAV; group II (n = 92), without a
remarkable CAV, was the control group.
results: Overall, the maximum heart rate was 86 ± 2% of what
was predicted, and the peak oxygen consumption was 18.8 ± 0.7
mL/kg/min (64% of that predicted). Groups I and II did not show
significant differences with regard to anthropometric data, hemodynamic
measurements, or number of rejection episodes. Group I exhibited
significant differences in maximum heart rate (120 ± 5 vs 134 ± 3
beats/min; p < 0.01), work capacity (47 ± 5% vs 59 ± 3%;
p < 0.05), peak oxygen uptake (16 ± 1 vs 20 ± 1
mL/min/kg; p < 0.01), and functional dead space ventilation
(31 ± 2 vs 26 ± 1; p < 0.01). Pretransplant status, etiology
of heart failure, ischemic time, and the number of rejection episodes
did not correlate with any exercise parameter.
Conclusions: Following heart transplantation, patients with
significant CAV show a diminished exercise capacity, a reduced oxygen
uptake, and a ventilation-perfusion mismatch. Thus, CAV may be a major
factor limiting exercise capacity in heart-transplant