PURPOSE: Chronic obstructive pulmonary disease (COPD) is independently associated with increased mortality in patients undergoing percutaneous coronary interventions (PCI). No previous study has correlated survival of cardiovascular patients undergoing PCI with the complete results of pulmonary function testing (PFT) in patients with COPD.results of pulmonary function testing (PFT) in patients with COPD.
METHODS: Consecutive patients who underwent PCI at the Mayo Clinic Rochester between 1995 and 2005 were identified and their medical records reviewed for the diagnosis of COPD (confirmed by ICD-9 coding) and availability of PFT results [including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), total lung capacity (TLC), diffusion capacity (DLCO), and residual volume (RV)]. Relevant demographic and clinical characteristics of these patients were also retrieved. Follow up survival was collected prospectively in the Mayo PCI registry at 6 month, 1 year, and then annually, and checked for accuracy as well as completeness.
RESULTS: 14,346 patients (age 67±12 years, 30% women, body-mass index 29±6 kg/m2), of which 1101 patients had a confirmed diagnosis of COPD (61% of these COPD patients had available PFT results). The mean follow up was 6.1±3.5 years. Patients with COPD had significantly reduced survival compared to those without COPD (p<0.0001), even after adjustment for confounders. The following variables were highly predictive of adverse outcomes after PCI: FEV1 (p<0.0001), FVC (p<0.0001), DLCO (p<0.0001), DLCO adjusted for hemoglobin (p<0.0001), and FEV1/FVC (p=0.021). Increasing severity of these variables correlated with a worse survival after PCI. Variables not associated with adverse outcome were TLC (p=0.28), RV (p=0.87).
CONCLUSIONS: Impaired FEV1, FVC, and DLCO correlate well with increased mortality after PCI in patients with COPD, while TLC and RV do not.
CLINICAL IMPLICATIONS: Indices of airway obstruction were highly predictive of survival among patients with COPD undergoing PCI, with more severe disease predicting greater mortality. The lack of predictive value of lung volumes (TLC and RV) may be due to the fact that worsening obstruction may increase lung volumes (not in all cases) whereas other disease processes that affect mortality tend to reduce lung volumes (e.g. heart failure, most other illnesses).
DISCLOSURE: The following authors have nothing to disclose: Tomas Konecny, Kiran Somers, Radim Spacek, Marek Orban, Lujza Galkova, Paul Scanlon, Charanjit Rihal
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