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ORIGINAL ARTICLE Cardiorespiratory Response to Exercise before and after Pulmonary Valve Replacement in Patients with Repaired Tetralogy of Fallot: A Retrospective Study and Systematic Review of the Literature Anna Sabate Rotes, MD,*† Jonathan N. Johnson, MD,* Harold M. Burkhart, MD,‡ Benjamin W. Eidem, MD,*§ Thomas G. Allison, PhD,§ and David J. Driscoll, MD* Divisions of *Pediatric Cardiology, ‡Cardiovascular Surgery, and §Cardiovascular Diseases, Mayo Clinic, Rochester, Minn, USA; †Universitat Autònoma de Barcelona, Barcelona, Spain ABSTRACT
Objective. To describe and analyze the cardiopulmonary responses to exercise for patients with repaired tetralogy of Fallot (TOF) before and after pulmonary valve replacement (PVR) and compare our results with those in the literature. Methods. Between 1973 and 2012, 278 patients had a first-time PVR after TOF repair. During their evaluations, 76 patients (27%) had exercise testing before PVR, and 63 (23%) had at least one test after PVR. There were 17 patients (average age at surgery 40 ± 14 years, 65% female) with both pre- and postoperative testing within 36 months of surgery. We then combined our results with previously reported studies for meta-analysis. Results. Patients who had exercise testing before PVR were older compared with those who did not have testing performed (37 ± 13 vs. 30 ± 17 years, P < .001). Preoperatively, patients achieved a peak heart rate of 153 ± 28 bpm and a peak VO2 of 21.5 ± 7.2 mL/kg/min (61 ± 15% of expected). Postoperatively, they achieved a peak heart rate of 156 ± 25 bpm and a peak VO2 of 23.3 ± 6.5 mL/kg/min (67 ± 15% of expected). Paired analysis demonstrated a significant increase in peak VO2 percentage (P = .04) but not for absolute VO2 measurements (mL/kg/min). We identified six published studies with similar usable data. Combining all seven data sets for meta-analysis, there was no significant change in peak VO2 following PVR (P = .2). Conclusions. Patients with repaired TOF have an abnormally low aerobic capacity at the time of PVR. We appreciated a modest improvement in percentage of predicted peak VO2 after PVR; however, meta-analysis of the available literature did not demonstrate an appreciable difference in aerobic capacity following PVR. Key Words. Tetralogy of Fallot; Exercise Test; Cardiac Surgery; Pulmonary Valve
Introduction
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ulmonary valve replacement (PVR) is frequently required for patients with repaired tetralogy of Fallot (TOF). The indications are based on the presence of symptoms or decreased exercise tolerance and the presence of severe pulmonary regurgitation (Class I) or symptomatic or sustained atrial and/or ventricular arrhythmias (Class IIa). For asymptomatic patients, impaired right ventricular function and dimension, associated severe pulmonary stenosis, and progressive tricuspid regurgitation are considered indications
© 2014 Wiley Periodicals, Inc.
for operation (Class IIa).1 PVR restores pulmonary valve function, but the effects on aerobic capacity have been inconsistent.2–9 Comparison to other studies on PVR is challenging, as many studies include different types of congenital heart disease and have small sample sizes. A recent metaanalysis focusing on postoperative outcomes in patients with repaired TOF undergoing PVR has been published but did not include results on exercise testing.10 The primary objective of this study was to describe and analyze our experience in exercise testing for patients with repaired TOF before and Congenit Heart Dis. 2014;••:••–••
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Sabate Rotes et al.
after PVR, and the secondary objective was to compare our results with those previously published in the literature.
Systematic Review and Meta-analysis The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist and flowchart were followed.13
Methods
Information Sources A literature search was performed by the Mayo Clinic library staff. The following databases were used: MEDLINE Database, EBM Reviews— Cochrane Database of Systematic Reviews, EBM Reviews—ACP Journal Club, Embase, National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM), Scopus, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE.
We performed a retrospective review of all patients who underwent first-time PVR following TOF repair between 1973 and 2012 at our institution (n = 278). To be included in this analysis, patients had to have had at least one cardiopulmonary exercise test with O2 uptake measured before PVR. Patients with pulmonary atresia, TOF with absent pulmonary valve, or concomitant atrioventricular canal defect were excluded. Patients who refused research authorization were also excluded. Overall, 76/278 (27%) patients met the inclusion criteria. The study was approved by the Mayo Clinic Institutional Review Board. Medical history and perioperative and follow-up data were collected using all available records. Exercise test results were obtained using a database in the Cardiovascular Health Clinic Laboratory.
Exercise Study The exercise testing protocol has previously been reported from our group.11,12 Briefly, exercise is performed with a previously calibrated cycle ergometer or motor-driven treadmill. The work load is based on patient gender, height, and body surface area. The patients are encouraged to exercise to the point of exhaustion, and only the results that the examiner considers to represent a maximal cardiopulmonary effort are included in the analysis. During the exercise test, heart rate, respiratory rate, blood pressure, oxygen uptake, carbon dioxide production, minute ventilation, tidal volume, and O2 saturation are recorded. Analysis of Our Cohort Descriptive statistics are reported as proportions for discrete data and means and standard deviations for continuous data, except for variables that are not normally distributed, for which median and range are used. Student’s t-test was used to compare continuous variables. The chi-square test of independence was used to compare categorical variables, except for cells with percentage of predicted VO2
ORIGINAL ARTICLE Cardiorespiratory Response to Exercise before and after Pulmonary Valve Replacement in Patients with Repaired Tetralogy of Fallot: A Retrospective Study and Systematic Review of the Literature Anna Sabate Rotes, MD,*† Jonathan N. Johnson, MD,* Harold M. Burkhart, MD,‡ Benjamin W. Eidem, MD,*§ Thomas G. Allison, PhD,§ and David J. Driscoll, MD* Divisions of *Pediatric Cardiology, ‡Cardiovascular Surgery, and §Cardiovascular Diseases, Mayo Clinic, Rochester, Minn, USA; †Universitat Autònoma de Barcelona, Barcelona, Spain ABSTRACT
Objective. To describe and analyze the cardiopulmonary responses to exercise for patients with repaired tetralogy of Fallot (TOF) before and after pulmonary valve replacement (PVR) and compare our results with those in the literature. Methods. Between 1973 and 2012, 278 patients had a first-time PVR after TOF repair. During their evaluations, 76 patients (27%) had exercise testing before PVR, and 63 (23%) had at least one test after PVR. There were 17 patients (average age at surgery 40 ± 14 years, 65% female) with both pre- and postoperative testing within 36 months of surgery. We then combined our results with previously reported studies for meta-analysis. Results. Patients who had exercise testing before PVR were older compared with those who did not have testing performed (37 ± 13 vs. 30 ± 17 years, P < .001). Preoperatively, patients achieved a peak heart rate of 153 ± 28 bpm and a peak VO2 of 21.5 ± 7.2 mL/kg/min (61 ± 15% of expected). Postoperatively, they achieved a peak heart rate of 156 ± 25 bpm and a peak VO2 of 23.3 ± 6.5 mL/kg/min (67 ± 15% of expected). Paired analysis demonstrated a significant increase in peak VO2 percentage (P = .04) but not for absolute VO2 measurements (mL/kg/min). We identified six published studies with similar usable data. Combining all seven data sets for meta-analysis, there was no significant change in peak VO2 following PVR (P = .2). Conclusions. Patients with repaired TOF have an abnormally low aerobic capacity at the time of PVR. We appreciated a modest improvement in percentage of predicted peak VO2 after PVR; however, meta-analysis of the available literature did not demonstrate an appreciable difference in aerobic capacity following PVR. Key Words. Tetralogy of Fallot; Exercise Test; Cardiac Surgery; Pulmonary Valve
Introduction
P
ulmonary valve replacement (PVR) is frequently required for patients with repaired tetralogy of Fallot (TOF). The indications are based on the presence of symptoms or decreased exercise tolerance and the presence of severe pulmonary regurgitation (Class I) or symptomatic or sustained atrial and/or ventricular arrhythmias (Class IIa). For asymptomatic patients, impaired right ventricular function and dimension, associated severe pulmonary stenosis, and progressive tricuspid regurgitation are considered indications
© 2014 Wiley Periodicals, Inc.
for operation (Class IIa).1 PVR restores pulmonary valve function, but the effects on aerobic capacity have been inconsistent.2–9 Comparison to other studies on PVR is challenging, as many studies include different types of congenital heart disease and have small sample sizes. A recent metaanalysis focusing on postoperative outcomes in patients with repaired TOF undergoing PVR has been published but did not include results on exercise testing.10 The primary objective of this study was to describe and analyze our experience in exercise testing for patients with repaired TOF before and Congenit Heart Dis. 2014;••:••–••
2
Sabate Rotes et al.
after PVR, and the secondary objective was to compare our results with those previously published in the literature.
Systematic Review and Meta-analysis The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist and flowchart were followed.13
Methods
Information Sources A literature search was performed by the Mayo Clinic library staff. The following databases were used: MEDLINE Database, EBM Reviews— Cochrane Database of Systematic Reviews, EBM Reviews—ACP Journal Club, Embase, National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM), Scopus, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE.
We performed a retrospective review of all patients who underwent first-time PVR following TOF repair between 1973 and 2012 at our institution (n = 278). To be included in this analysis, patients had to have had at least one cardiopulmonary exercise test with O2 uptake measured before PVR. Patients with pulmonary atresia, TOF with absent pulmonary valve, or concomitant atrioventricular canal defect were excluded. Patients who refused research authorization were also excluded. Overall, 76/278 (27%) patients met the inclusion criteria. The study was approved by the Mayo Clinic Institutional Review Board. Medical history and perioperative and follow-up data were collected using all available records. Exercise test results were obtained using a database in the Cardiovascular Health Clinic Laboratory.
Exercise Study The exercise testing protocol has previously been reported from our group.11,12 Briefly, exercise is performed with a previously calibrated cycle ergometer or motor-driven treadmill. The work load is based on patient gender, height, and body surface area. The patients are encouraged to exercise to the point of exhaustion, and only the results that the examiner considers to represent a maximal cardiopulmonary effort are included in the analysis. During the exercise test, heart rate, respiratory rate, blood pressure, oxygen uptake, carbon dioxide production, minute ventilation, tidal volume, and O2 saturation are recorded. Analysis of Our Cohort Descriptive statistics are reported as proportions for discrete data and means and standard deviations for continuous data, except for variables that are not normally distributed, for which median and range are used. Student’s t-test was used to compare continuous variables. The chi-square test of independence was used to compare categorical variables, except for cells with percentage of predicted VO2
