Sk. Epstein et al., PREDICTING COMPLICATIONS AFTER PULMONARY RESECTION - PREOPERATIVE EXERCISE TESTING VS A MULTIFACTORIAL CARDIOPULMONARY RISK INDEX, Chest, 104(3), 1993, pp. 694-700
Recent studies have used preoperative cardiopulmonary exercise testing
to improve risk assessment of pulmonary resection for lung cancer. Th
ese studies have demonstrated inconsistent correlation between peak ox
ygen uptake (VO2) and postoperative complications but have not systema
tically examined other methods of risk stratification. We analyzed the
findings in 42 patients who had cardiopulmonary exercise testing prio
r to lung cancer resection. Preoperative clinical data combining pulmo
nary factors (obesity, productive cough, wheezing, tobacco use, ratio
of the forced expiratory volume in 1 s over the forced vital capacity
[FEV1/FVC] <70 percent, and PaCO2 >45 mm Hg), and an established cardi
ac risk index were used to generate a cardiopulmonary risk index (CPRI
). When analyzed using the risk index, the incidence of postoperative
complications increased with higher CPRI scores. Those with a CPRI of
4 or greater were 22 times more likely to develop a complication, comp
ared to a CPRI of less than 4 (p<0.0001). We found that patients with
a peak VO2 less than 500 ml/m2/min (body surface area) were 6 times mo
re likely to experience a cardiopulmonary complication (p<0.05). With
multiple logistic regression analysis, peak VO2 was not an independent
predictor of postoperative complications. Analysis also demonstrated
that a CPRI of 4 or greater was associated with significant reductions
in peak VO2. We conclude that both the peak VO2 during cardiopulmonar
y exercise testing and a multifactorial CPRI are highly predictive of
complications after lung resection. Adding the peak VO2 did not enhanc
e the risk estimation generated by the CPRI. The association between p
ostoperative complications and peak VO2 may be explained by the correl
ation between identifiable cardiopulmonary disease (CPRI) and reduced
oxygen uptake with exercise.