Microneurography and venous occlusion plethysmography in heart failure: correlation with prognosis.

BACKGROUND Microneurography and venous occlusion plethysmography can be considered methods of assessment of the sympathetic activity. OBJECTIVE To evaluate the intensity of the sympathetic activity through microneurography and venous occlusion plethysmography in patients with heart failure (HF) and correlate this intensity with prognosis. METHODS 52 patients with HF (ejection fraction < 45% at the echocardiogram): 12 with FCII and 40 with FCIV. After compensation, the muscular sympathetic nervous activity (MSNA) in the peroneal nerve (microneurography) and the muscular blood flow (MBF) in the forearm were evaluated (venous occlusion plethysmography). After an 18-month follow-up, the patients were divided in 3 groups: 12 with FCII, 19 with FCIV that did not die and 21 with FCIV that died. The intensity of the sympathetic activity was compared in the three different groups. RESULTS Patients with FCII presented lower MSNA (p=0.026) and higher MBF (p=0.045) than the ones with FCIV that did not die. The patients with FCIV that died presented higher MSNA (p<0.001) and lower MBF (p=0.002) than the patients with FCIV that did not die. ROC curve: cutoff >53.5 impulses/min for MSNA (S=90.55. E=73.68%) and < 1.81 ml/min/100gr for MBF (S=90.4%. E=73.7%). Kaplan-Meier curve: higher survival with MSNA < 53.5 impulses/min (p<0.001), and/or MBF >1.81 ml/min/100gr (P<0.001). Logistic regression analysis: the higher the MSNA and the lower the MBF, the higher is the probability of death. CONCLUSION The intensity of the MSNA and the MBF can be considered prognostic markers in advanced HF.