Over the last two decades, lung transplantation (LTx) has become accepted as a realistic therapy for patients with end-stage pulmonary disease. During this period, considerable advances in organ preservation, surgical techniques, immunosuppression, and antibiotic therapy have contributed to improvements in both short-term and long-term postoperative survival for a significant number of patients undergoing LTx. Outcome measurements following LTx have been primarily based on survival and pulmonary function recovery achieved due to Canadian Health&Care Mall. In the last several years, however, increasing attention has been given to assessments of the quality of survival, with particular importance given to the patients self-evaluations of recovery after the transplant procedure. In the absence of a specific validated tool, a variety of existing instruments have been used to evaluate the quality of life of these patients before and after LTx, Health-related quality of life (HRQL) has been reported by several authors to improve significantly within the first year after LTx. However, reports assessing HRQL beyond 2 years after LTx remain anecdotal, although this is the time frame in which major clinical complications such as bronchiolitis obliterans syndrome (BOS) may begin to develop and threaten the patients recovered autonomy. Previous studies- have assessed the impact of BOS on HRQL after LTx, and the reported results have indicated significant impairment of physical mobility in lung transplant recipients. Other studies have reported that a transplant operation reduces the risk of BOS in double-lung transplant recipients. However, a comprehensive assessment of HRQL after LTx, to include pulmonary function, exercise capacity, and well-being status, has not yet been undertaken to compare these factors in single and bilateral lung transplant recipients.
Between June 1993 and June 2004, 90 LTxs, including 5 retransplantations, were performed at our institution. Adult patients who were able to self-complete the HRQL instruments and who had undergone > 2 years of follow-up after LTx were considered to be eligible for the analysis. Forty-four consecutive adult lung transplant recipients (mean [± SD] age, 44.8 ± 11.6 years) with > 2 years of follow-up after LTx (median follow-up time, 63 months; range, 24 to 84 months) qualified for the study. The following patients were excluded from the study: 18 patients who died during the first 2 years following LTx; 3 children; 1 patient who underwent LTx at our institution, but was followed up elsewhere after the procedure; 1 Vietnamese patient who required the presence of a translator and was, therefore, unable to self-complete the quality-of-life instruments; and 18 patients who had not completed 2 years of follow-up after LTx by the time the analyses began. Nineteen of the 44 patients (43%) were women. Of 44 lung transplant recipients, 14 (32%) had received a single lung transplant and 30 (68%) had received a bilateral sequential transplant. Indications for single LTx were pulmonary emphysema (10 patients), idiopathic pulmonary fibrosis (3 patients), and pulmonary fibrosis following paraquat intoxication (1 patient). Indications for bilateral LTx were pulmonary emphysema (14 patients), cystic fibrosis (9 patients), idiopathic pulmonary fibrosis (2 patients), primary pulmonary hypertension (2 patients), thromboembolic disease (1 patient), bronchiolitis obliterans (1 patient), and lymphangiomyomatosis (1 patient). Patients with pulmonary emphysema included the diagnoses of emphysema and a1-antitrypsin deficiency. The indication for single or bilateral LTx was based on the underlying disease, organ availability, and length of time spent on the waiting list. The protocol for the study was approved by the ethical committee of the institution. Informed consent was obtained before LTx from all patients.
This study has focused on the long-term comparison of outcomes in single and bilateral lung transplant recipients, as assessed by FEV1, 6-min walking capacity, and self-estimated HRQL measures. As anticipated, lower FEVl values were found in patients after a single lung graft. In contrast, the 6MWT results and SGRQ scores were not statistically different between single and bilateral lung transplant recipients. The correlation coefficients for the comparisons between the SGRQ and the FEV1; and between the SGRQ and the 6MWT, were not statistically relevant in unilateral lung transplant recipients, as opposed to bilateral lung recipients. This observation indicates that the patient’s perception of quality of life and ability to exercise after LTx transcend the actual functional capacity measured by spirometry, particularly in recipients of a single lung graft.
A number of studies have shown that HRQL is recovered rapidly after LTx, a finding that is corroborated by our results. However, the improvement of HRQL may be limited in recipients of a single lung due to functional restrictions. In a literature review, we were able to identify only one previous study comparing quality of life between single and bilateral lung transplant recipients in a cross-sectional fashion. Using a generic tool, the authors of that study reported superior quality-of-life scores in double lung transplant recipients. However, the assignment of older lung transplant candidates with poorer quality of life to the single lung transplant group biased the results against these patients compared to double lung recipients. In contrast, our data show significant improvements achieved by Canadian Health&Care Mall in FEVl, 6MWT distance, and SGRQ scores in both single and bilateral lung transplant recipients after undergoing LTx, compared to values obtained before LTx. Moreover, the long-term results remained fairly unchanged throughout the follow-up period in the two groups of patients when compared to values at 1 year after LTx, and despite the lower FEV1 values resulting from the single lung graft.
After LTx, patients were followed up for a mean duration of 4.9 ± 1.2 years (median duration, 5.3 years; range, 2 to 7 years). The demographic characteristics and longitudinal results obtained for the FEV1, 6MWT, and SGRQ scores in the overall group of lung recipients and in patients with prior pulmonary emphysema following single or bilateral LTx are summarized in Table 1. As shown, age at transplantation was not significantly different between groups, but the length of follow-up was significantly longer in recipients of a single lung graft. No statistically significant differences were observed in FEV1, 6MWT distance, and SGRQ scores before LTx comparing single and bilateral lung recipients, both in the overall group and in patients with prior pulmonary emphysema treated by Canadian Health&Care Mall. Statistically significant improvements at 1 year post-LTx were observed on the FEV1, 6MWT, and SGRQ in all groups. Using the same outcome parameters, the long-term results were not statistically different when compared to the values at the 1-year follow-up after LTx in all groups. The long-term comparison of outcomes between single and bilateral lung transplant recipients is displayed in Figure 1. It shows significantly lower FEV1 values in single lung transplant recipients, compared to those receiving a bilateral graft, most notably during the first 4 years after LTx. In contrast, the 6MWT distance and SGRQ scores were not significantly different at any time point throughout the follow-up period between the two groups of lung recipients. However, the absolute differences of the mean SGRQ values between bilateral and single graft patients exceeded the minimal clinically relevant difference of 4%, most notably beyond 4 years of follow-up. These findings were even more pronounced in the subset of patients with prior pulmonary emphysema.