Heart Failure Impairs Muscle Blood Flow and Endurance Exercise Tolerance in COPD

Abstract

Heart failure, a prevalent and disabling co-morbidity of COPD, may impair cardiac output and muscle blood flow thereby contributing to exercise intolerance. To investigate the role of impaired central and peripheral hemodynamics in limiting exercise tolerance in COPD-heart failure overlap, cycle ergometer exercise tests at 20% and 80% peak work rate were performed by overlap (FEV1 = 56.9 ± 15.9% predicted, ejection fraction = 32.5 ± 6.9%; N = 16), FEV1-matched COPD (N = 16), ejection fraction-matched heart failure patients (N = 15) and controls (N = 12). Differences (Δ) in cardiac output (impedance cardiography) and vastus lateralis blood flow (indocyanine green) and deoxygenation (near-infrared spectroscopy) between work rates were expressed relative to concurrent changes in muscle metabolic demands (ΔO2 uptake). Overlap patients had approximately 30% lower endurance exercise tolerance than COPD and heart failure (p < 0.05). ΔBlood flow was closely proportional to Δcardiac output in all groups (r = 0.89-0.98; p < 0.01). Overlap showed the largest impairments in Δcardiac output/ΔO2 uptake and Δblood flow/ΔO2 uptake (p < 0.05). Systemic arterial oxygenation, however, was preserved in overlap compared to COPD. Blunted limb perfusion was related to greater muscle deoxygenation and lactate concentration in overlap (r = 0.78 and r = 0.73, respectively; p < 0.05). ΔBlood flow/ΔO2 uptake was related to time to exercise intolerance only in overlap and heart failure (p < 0.01). In conclusion, COPD and heart failure add to decrease exercising cardiac output and skeletal muscle perfusion to a greater extent than that expected by heart failure alone. Treatment strategies that increase muscle O2 delivery and/or decrease O2 demand may be particularly helpful to improve exercise tolerance in COPD patients presenting heart failure as co-morbidity.

Effects of high- and moderate-intensity exercise on central hemodynamic and oxygen uptake recovery kinetics in CHF-COPD overlap

“…Recently, a prospective study assessed the role of central and peripheral impairments in the O 2 transport pathway in limiting exercise tolerance in patients with COPD and CHF overlap compared to FEV 1 -matched COPD and LVEF-matched CHF patients. Besides the fact that patients with CHF-COPD had lower endurance exercise tolerance they also presented a greater impairment in leg muscle blood flow, but not arterial oxygenation, than CHF alone (37). Although in the present study peripheral hemodynamics was not assessed, we speculated that during recovery from exercise bouts, the impairment of muscle blood flow can also contribute to slow the HR, .…”

The Medusa faces of dyspnoea in COPD

“…The Brazilian and Canadian researchers demonstrate that muscle blood flow impairment was markedly greater in overlap patients compared not only to COPD but also to heart failure patients. This reduced convective O 2 delivery in overlap patients was accompanied by relatively greater fractional O 2 extraction and higher blood lactate concentration [11].…”

“…Identification of the subgroup of COPD-heart failure patients with excessive exertional ventilation may guide therapeutic and rehabilitative interventions to positively impact on exertional dyspnoea and to select rehabilitative strategies with low-to-minimal ventilator stress [7]. The results reported in this issue of the European Respiratory Journal and in previous papers suggest that overlap patients are particularly prone to responding to interventions that increase skeletal muscle O 2 delivery and/or reduce O 2 demand [11,12]. Such leg muscle oxygenation during exercise can also be achieved by respiratory muscle unloading by noninvasive positive pressure ventilation [15].…”

An update on pulmonary rehabilitation techniques for patients with chronic obstructive pulmonary disease

“…In heart failure, low cardiac output, global sympathetically mediated vasoconstriction and microvascular abnormalities characteristically compromise appendicular muscle blood flow [24]. Therefore, it can be expected that muscle blood flow impairment is markedly greater in COPD-HF overlap patients compared not only to COPD but also to HF patients [25].…”