Impact of Pre-Heart Transplant Pulmonary Function Tests on Post-Transplant Pulmonary Outcomes

Abstract

<h3>Purpose</h3> Pulmonary function tests (PFT) are a component of heart transplant (HT) evaluation. In cardiac surgery, abnormal PFTs, especially reduced DLCO, are associated with poor outcomes. We sought to evaluate the impact of pre-HT PFTs on post-HT pulmonary outcomes. <h3>Methods</h3> We retrospectively reviewed 235 consecutive HT recipients and collected pre-HT data including PFTs. PFT patterns were classified according to ATS/ERS standards (Severe restrictive ventilatory defect (RVD): [FEV1/FVC≥70%, FVC<80% & FEV1<50%], Severe obstructive ventilatory defect (OVD): [FEV1/FVC<70% & FEV1<80%]). The combined endpoint included reintubation, prolonged intubation (greater than 5 days), tracheostomy, or post-HT treated pneumonia. <h3>Results</h3> 151 patients had pre-HT PFT data. The mean age was 55±12 years, 75% were male, 59% were bridged with a LVAD, and 52% were former smokers. 28 patients (18%) had normal PFTs, 81 (53%) had RVD (10 severe), and 42 (29%) had OVD (10 severe). Among 136 patients with DLCO data, 30 (22%) had a severely reduced DLCO (<40% predicted). Overall, 37 patients (24.5%) experienced an adverse pulmonary event. Among those with severely reduced DLCO, 40% met the combined endpoint (vs 23.6% with mild-moderate DLCO reduction, P=0.07). Among the 10 patients with severe OVD, 6 (60%) experienced the combined endpoint (vs. 31.3% of those with mild-moderate OVD p=0.14). 40% with severe RVD experienced the combined endpoint (vs. 22% with mild-moderate RVD, p=0.20). Those with severe lung disease (OVD, RVD, DLCO) had a 3.1 fold increased odds of post-HT pulmonary complications (95% CI 1.2-8.0, p=0.03). Similarly, post-HT ICU length of stay was significantly longer 16.2±19.9 vs. 7.3±8.6 days (p=0.03) and 90 day survival was significantly reduced 66.7% vs. 94.7, p=0.002 (Figure). <h3>Conclusion</h3> Severe abnormalities of pre-HT PFTs are associated with increased odds of post-HT pulmonary complications, ICU length of stay, and 90 day mortality. Severely reduced DLCO seems to be the strongest predictor among PFT variables.