Skin microvascular distensibility and structural microangiopathy in idiopathic dilated cardiomyopathy and after heart transplantation

Inotropic agents improve the peripheral microcirculation of patients with end-stage chronic heart failure

BACKGROUND

Skeletal muscle microcirculation impairment in patients with chronic heart failure (CHF) seems to correlate with disease severity. We evaluated the microcirculation by near-infrared spectroscopy (NIRS) occlusion technique before and after inotropic infusion.

METHODS

We evaluated 25 patients with stable CHF, 30 patients with end-stage CHF (ESCHF) receiving treatment with intermittent infusion of inotropic agents, and 12 healthy subjects. Thenar muscle tissue oxygen saturation (StO(2)%) was measured noninvasively by NIRS before, during, and after 3-minute occlusion of the brachial artery (occlusion technique) in all subjects and in patients with ESCHF before and after 6 hours of inotropic infusion (dobutamine and/or levosimendan) or placebo (N = 5).

RESULTS

Patients with ESCHF or CHF presented significantly lower StO(2)% than healthy subjects (74.5% +/- 7%, 78.6% +/- 6%, and 85% +/- 5%, respectively; P = .0001), lower oxygen consumption rate during occlusion (24.6% +/- 8%/min, 28.6% +/- 10%/min, and 38.1% +/- 11.1%/min, respectively; P = .001), and lower reperfusion rate (327% +/- 141%/min, 410% +/- 106%/min, and 480% +/- 133%/min, respectively; P = .002). After 6 hours of inotropic infusion, patients with ESCHF showed significantly increased StO(2)% (74.5% +/- 7% to 82% +/- 9%, P = .001), oxygen consumption rate (24.6% +/- 8%/min to 29.3% +/- 8%/min, P = .009), and reperfusion rate (327% +/- 141%/min to 467% +/- 151%/min, P = .001). No statistical difference was noted in the placebo group.

CONCLUSION

Peripheral muscle microcirculation as assessed by NIRS is impaired in patients with CHF. This impairment is partially reversed by infusion of inotropic agents in patients with ESCHF.

Microvascular abnormalities in chronic heart failure: a cross-sectional analysis

OBJECTIVES

Similar to what has been found in hypertension, elevated peripheral resistance in chronic heart failure (CHF) might be related to microvascular constriction and rarefaction. Our objective was to evaluate both structural and functional microvascular changes in patients with CHF in relation to left ventricular function and neurohumoral activation.

METHODS

In 25 patients with mild and severe CHF (New York Heart Association class I-II [n = 11] and class III-IV [n = 14]) and 10 age-matched healthy subjects, we studied microvascular density, diameters, and morphology of the bulbar conjunctiva and skin nailfold using intravital microscopy.

RESULTS

Total conjunctival microvascular density was higher in patients with mild heart failure compared with healthy controls, whereas it was lower in severe heart failure (medians, 6.75, 4.31, and 3.56 mm/mm2, respectively, p < 0.01). In patients with heart failure, venular density was correlated with left ventricular ejection fraction. Nailfold capillary recruitment during postocclusive reactive hyperemia, a measure of functional reserve capacity, was impaired in patients with severe CHF (p < 0.05). Furthermore, in severe CHF, more abnormal capillaries and enlarged diameters were found in the nailfold (p < 0.05).

CONCLUSIONS

In heart failure, several microvascular abnormalities occur that differ, depending on the severity of this condition.

Exercise skeletal muscle blood flow is related to peripheral microvascular stiffness in idiopathic dilated cardiomyopathy

Peripheral microvascular function plays an important role in congestive heart failure (CHF). Decreased exercise blood flow and microvascular dysfunction have been described in CHF and both factors are regarded as parameters that might influence exercise capacity in these patients. Whether these factors are related to or can be characterized in clinical severity of CHF has not been elucidated in this population. Skeletal muscle blood flow (SMBF) was measured continuously noninvasively, by means of the local isotope washout technique using (133)Xenon, in musculus tibialis anterior during graded maximal supine bicycle exercise. The distensibility in skeletal muscle was measured in a papaverine-relaxed vascular bed using (99m)Tc-pertechnetate. The investigation included 20 patients with moderate CHF (NYHA II), 11 patients with severe CHF (NYHA III, IV) due to idiopathic dilated cardiomyopathy (IDCM), and 31 age-matched healthy subjects. The maximal SMBF level was significantly lower in severe CHF (3.6 +/- 2.5 (ml x (100 g x min)(-1))) compared with moderate CHF (8.6 +/- 5.1 (ml x (100 g x min)(-1)); P < 0.005) and controls (11.0 +/- 4.1 (ml x (100 g x min)(-1)); P < 0.0001), but similar between moderate CHF and controls. Distensibility in skeletal muscle was decreased in severe CHF (12 +/- 8%) compared with controls (44 +/- 17%; P < 0.0001 vs severe CHF) and decreased with increasing severity of CHF (moderate CHF, 23 +/- 14%; P < 0.0005 vs controls). In CHF patients, a relationship was demonstrated between skeletal muscle distensibility and the maximal SMBF (P < 0.0001; r = 0.70). Moreover, maximal SMBF correlated directly to exercise time (P < 0.005; r = 0.54). Patients with CHF have reduced exercise SMBF, which may be a limiting factor for the reduced maximal exercise capacity. Moreover, microvascular distensibility in skeletal muscle is reduced and correlates to maximal exercise SMBF. Furthermore, maximal SMBF correlates to exercise time. This implies that increased skeletal muscle microvascular stiffness may contribute to the reduced blood flow during exercise and SMBF may partly limit exercise performance in CHF patients due to IDCM.

Exercise blod flow and microvascualr distensibility in skeletal muscle normalize after heart transplantation

This study investigated the effect of heart transplantation (HTX) on reduced exercise blood flow and microvascular stiffness in patients with congestive heart failure (CHF). Skeletal muscle blood flow (SMBF) during graded maximal supine bicycle exercise and microvascular distensibility (i.e., stiffness) were measured in musculus tibialis anterior by the isotope washout method. Measurements were performed in a cross-sectional study with 31 CHF patients and 28 patients, mean 9 months after HTX, and in a longitudinal study in 12 CHF patients before, 3 months, and 14 months after HTX, and in 31 healthy controls. Maximal SMBF: In the cross-sectional study, maximal SMBF was reduced in severe CHF patients (3.6 +/- 2.5 mL (100 g min)(-1)) and increased after HTX (7.7 +/- 4.8; p < 0.01 versus controls (11 +/- 4.1). Maximal SMBF was reduced in CHF patients (5.8 +/- 4.0) and reversed to normalization 3 months after HTX (10.3 +/- 4.4) in the longitudinal study. Microvascular distensibility: The distensibility was reduced (severe CHF, 12 +/- 8%; moderate CHF, 23 +/- 14%) in the cross-sectional study and increased after HTX towards normalization (38 +/-20%; controls: 44 +/- 17). In the longitudinal study, distensibility in CHF patients (14 +/- 6%) increased gradually to 32 +/- 12% (p < 0.005) at 3 months and normalized 14 months after HTX (46 +/- 17%). HTX gradually reversed the reduced SMBF and microvascular distensibility in CHF patients towards normalization.