Pulmonary function tests overestimate chronic pulmonary disease in patients with severe aortic stenosis

Pulmonary dysfunction is an important risk factor for postoperative complications after cardiac surgery, and severe chronic obstructive pulmonary disease (COPD) is considered a relative contraindication to aortic valve replacement. Pulmonary function tests may mistakenly diagnose patients as having COPD, when in fact they have pulmonary dysfunction due to heart failure that potentially will improve with valve replacement.

Between January 2009 and July 2011, 214 consecutive patients underwent pulmonary function testing as part of their preoperative screening. Based on the testing, 143 patients were identified as having COPD (52 mild, 42 moderate, and 49 severe), according to The Society of Thoracic Surgery definition. A total of 71 patients had follow-up tests performed at 6 to 12 months postprocedure.

A recent smoking history was present in 55 of 214 (25.7%) patients. Aortic valve replacement was performed in 13.6% (29 of 214) of patients by a conventional surgical approach, in 39.3% (84 of 214) by a transfemoral approach, and in 47.2% (101 of 214) by a transapical approach. Mortality was not significantly different in patients with COPD (12 of 71, 16.9%) compared with patients without COPD (37 of 143, 25.9%), p = 0.141. Logistic regression analyses failed to identify preoperative COPD severity category (p = 0.332) as a predictor for mortality. Comparison of pre- and postprocedure tests revealed that 42% (30 of 71) of patients with COPD showed improvement of one COPD severity category or more, including 40% (12 of 30) of patients in the mild group, 43% (9 of 21) of patients in the moderate group, and 45% (9 of 20) of patients in the severe category.

Abnormal pulmonary function improves in a significant number of patients with severe aortic stenosis after valve replacement.