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Evidence for structural alterations in resistance arteries of patients with severe congestive heart failure
Abstract:
Congestive heart failure (CHF) is characterized by an increase in total peripheral resistance. It was the specific aim of this study to investigate whether structural factors participate in the increased peripheral resistance that can be observed in severe heart failure. We determined forearm vascular resistance (FVR) at rest and after 10 min ischemia (Rmin; mm Hg/ml/min/100 ml) using venous occlusion plethysmography. Rmin was studied since it is largely dependent on the structural characteristics of resistance arteries. 24 patients with CHF [71.5 +/- 2.3 years; New York Heart Association (NYHA) functional class I-IV] with no history of arterial hypertension and casual arterial blood pressure < 140/90 mm Hg and 24 normotensive healthy control subjects (52.5 +/- 4.1 years) were included in our study. The patients were subdivided into those with 'mild' (NYHA class I and II; n = 10) and 'severe' (NYHA class III and IV; n = 14) heart failure. There were no significant differences between the two groups for echocardiographically determined ejection fraction and mean arterial blood pressure. Resting FVR averaged 40.5 +/- 4.4 mm Hg/ml/min/100 ml in control subjects and was 43.6 +/- 7.9 (nonsignificant vs. control) and 51.0 +/- 5 mm Hg/ml/min/100 ml (p < 0.05 vs. control) in patients with mild and severe CHF, respectively. No significant correlation between age and Rmin could be demonstrated in either the patient or the control group. Furthermore, Rmin did not differ between patients with mild CHF and control subjects. However, Rmin was significantly elevated in patients with severe CHF (5.7 +/- 0.39 mm Hg/ml/min/100 ml) as compared to patients with mild CHF (4.0 +/- 0.39 mm Hg/ml/min/100 ml; p < 0.05) and controls (4.5 +/- 0.26 mm Hg/ml/min/100 ml; p < 0.05). In conclusion, our study supports the concept that structural alterations contribute to the increased peripheral resistance in patients with heart failure. These changes are correlated with the severity of clinical symptoms.