VE/VCO₂ slope and its prognostic value in patients with chronic heart failure

The minute ventilation/carbon dioxide production (VE/VCO₂) slope has been widely demonstrated to have strong prognostic value in patients with chronic heart failure (CHF), and the risk of mortality is believed to increase when the VE/VCO₂ slope is >32.8; however, there is little evidence concerning the prognostic value of the VE/VCO₂ slope in Chinese patients. In the present study, the prognostic value of the VE/VCO₂ slope was investigated in patients with CHF. A total of 258 subjects underwent symptom-limited cardiopulmonary exercise testing (CPET) and were divided into CHF (113 males and 16 females; LVEF <0.49) and control (106 males and 23 females) groups. The cardiac-related events over a median 33.7-month follow-up period subsequent to the CPET were evaluated using receiver operating characteristic curve analysis. The VE/VCO₂ slope was significantly different between the CHF and control groups (P<0.001). The area under the curve (AUC) for the VE/VCO₂ slope in predicting cardiac-related mortalities in the patients with CHF was 0.670 (P<0.05), and the sensitivity and specificity of the VE/VCO₂ slope were 0.667 and 0.620, respectively. The optimal threshold of the VE/VCO₂ slope for predicting cardiac-related mortalities in patients with CHF was ≥39.3. The AUC for the VE/VCO₂ slope in predicting cardiac-related hospitalizations in patients with CHF was 0.682 (P<0.05), and the sensitivity and specificity of the VE/VCO₂ slope were 0.631 and 0.778, respectively. The optimal threshold of the VE/VCO₂ slope for predicting cardiac-related hospitalizations in patients with CHF was ≥32.9. In conclusion, ventilatory efficiency decreases in patients with CHF. The VE/VCO₂ slope is a strong predictor of cardiac-related mortalities in the patients with CHF analyzed.