Table 1.
Baseline Demographics
| Variable | Group 1 (n=21) Younger | Group 2 (n=19) Older | P Value |
|---|---|---|---|
| Median age, y | 62±7.5 | 75±4.6 | |
| Men, % | 43% | 58% | 0.355 |
| Weight, kg | 89.7±21.6 | 83.2±16.8 | 0.301 |
| BMI, kg/m2 | 32.1±6.3 | 29.5±3.8 | 0.141 |
| Resting hemodynamics | |||
| HR, beats/min | 69.3±14.2 | 65.7±8.6 | 0.338 |
| Systolic BP, mm Hg | 145±15 | 157±13 | 0.012* |
| Mean PAP, mm Hg | 20±6 | 22±9 | 0.449 |
| PCWP, mm Hg | 12±5 | 13±5 | 0.408 |
| Cardiac output, L/min | 5.7±1.1 | 4.8±1.2 | 0.019* |
| Cardiac index, L/min per m2 | 2.9±0.5 | 2.5±0.4 | 0.015* |
| Indexed stroke volume, mL/m2 | 43±10 | 38±7 | 0.111 |
| SVR, mm Hg/min per mL−1 | 17±5 | 21±6 | 0.064 |
| LVSWI, g/m2 per beat | 97.7±22.3 | 87.5±22.7 | 0.161 |
| Hemoglobin, g/L | 129.8±17.9 | 135.8±15.3 | 0.970 |
| Mixed venous oxygen saturation, % | 72.8±6.8 | 69.2±6.3 | 0.096 |
| Arteriovenous oxygen difference, mL | 4.5±1.4 | 5.1±1.0 | 0.126 |
| VO2, mL/min | 264.0±93.6 | 245.5±76.6 | 0.511 |
| VO2, mL/kg per min | 3.13±1.53 | 3.00±0.89 | 0.756 |
| Oxygen delivery | 1033.1±240.6 | 857.2±275.1 | 0.043* |
| Oxygen extraction ratio, % | 25.1±7.4 | 29.4±6.3 | 0.065 |
Continuous variables are presented as mean±SD. *P value reflects comparative t test, with significance defined as <0.05. BMI indicates body mass index; BP, blood pressure; HR, heart rate; LVSWI, left ventricular stroke work index; PAP, pulmonary artery pressure; PCWP, pulmonary capillary wedge pressure; SVR, systemic vascular resistance; VO2, oxygen consumption.