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Peak oxygen consumption and resting left ventricular ejection fraction changes after cardiomyoplasty at 6-month
E A Bocchi1, G V Guimarães, L F Moreira
1Heart Institute, São Paulo (Brazil), University Medical School.
Insights
Cardiomyoplasty improved heart failure symptoms and ejection fraction in patients. Patients with lower pre-surgery peak oxygen consumption (VO2) showed greater exercise capacity gains after the procedure.
Area of Science:
- Cardiology
- Cardiac Surgery
- Exercise Physiology
Background:
- The impact of cardiomyoplasty on cardiopulmonary exercise test metrics remains incompletely understood.
- Refractory heart failure patients (NYHA class III) often have impaired exercise capacity.
Purpose of the Study:
- To evaluate the effects of cardiomyoplasty on exercise capacity and left ventricular ejection fraction (LVEF) in heart failure patients.
- To identify predictors of improved outcomes after cardiomyoplasty.
Main Methods:
- Assessed 19 heart failure patients (NYHA class III) before and 6 months after cardiomyoplasty.
- Measured maximum oxygen consumption (peak VO2), NYHA functional class, and LVEF.
- Analyzed outcomes based on pre-operative peak VO2 (< or > 14 mL/kg/min).
Main Results:
- Overall peak VO2 and exercise time significantly improved post-surgery (P=.059 and P<.04, respectively).
- Patients with pre-operative peak VO2 < 14 mL/kg/min demonstrated significant increases in peak VO2 (P=.02) and exercise time (P<.01).
- LVEF improved significantly (P=.02), with a weak correlation between changes in LVEF and peak VO2 (r=.48, P=.048).
Conclusions:
- Cardiomyoplasty effectively improves NYHA functional class and LVEF in heart failure patients.
- Pre-operative peak VO2 < 14 mL/kg/min may indicate suitability for cardiomyoplasty to enhance exercise capacity.
- Improvements in LVEF are partially linked to enhanced exercise capacity post-procedure.
Background:
The effects of cardiomyoplasty on cardiopulmonary exercise test characteristics are not fully known.
Methods And Results:
We determined in 19 patients who underwent cardiomyoplasty for treatment of refractory heart failure (New York Heart Association [NYHA] functional class III) before (pre) and at 6-month follow-up (post) maximum oxygen consumption (peak VO2), NYHA functional class, and resting left ventricular ejection fraction (LVEF) (MUGA). We analyzed the results according to pre peak VO2 < or > 14 mL/kg per minute and the correlation between the changes in absolute values of LVEF and peak VO2. Pre- and post-peak VO2 values were 15.9 +/- 4.4 and 18.6 +/- 6.4 mL/kg per minute, respectively (P = .059). In the subgroup with pre-peak VO2 < 14 mL/kg per minute, the peak VO2 increased from 11.1 +/- 1.9 to 16.4 +/- 6.2 mL/kg per minute (P = .02). The subgroup with peak VO2 > 14 mL/kg per minute showed pre- and post-peak VO2 of 19.2 +/- 2.6 and of 20.1 +/- 7 mL/kg per minute, respectively (P = .06). The pre-total exercise time of the entire group increased from 688.4 +/- 222.1 to 833.7 +/- 241.6 seconds (P < .04). For the subgroup with preoperative peak VO2 < 14 mL/kg per minute, exercise time improved from 585 +/- 76.9 to 825 +/- 186.3 seconds (P < .01). In the subgroup with preoperative VO2 > 14 mL/kg per minute, the preexercise and postexercise time was 763.6 +/- 264.4 and 840 +/- 282 seconds, respectively (P = .4). Pre-LVEF increased from 20.6 +/- 3.3% to 24.2 +/- 7.8% at 6 months of follow-up (P = .02). At 6 months of follow-up, 9 patients were in NYHA functional class I and 10 were in class II. There was no correlation between LVEF values and absolute values of peak VO2 before (r = .123, P = .6) and after (r = .27, P = .2) cardiomyoplasty. A weak correlation was observed between the changes in absolute values of peak VO2 and LVEF from the preoperative to the postoperative period (r = .48, P = .048).
Conclusions:
Cardiomyoplasty is a useful method for improving NYHA functional class and LVEF in patients with heart failure. Peak VO2 < 14 mL/kg per minute before cardiomyoplasty may be a selection criterion with which to determine improved exercise capacity after surgery. The effects of cardiomyoplasty on LVEF appear to be partially associated with maximum exercise capacity changes.