Bilateral lung transplantation for pulmonary hypertension

Early implementation of renal replacement therapy after lung transplantation does not impair long-term kidney function in patients with idiopathic pulmonary arterial hypertension

OBJECTIVES

In patients with idiopathic pulmonary arterial hypertension, cardiac function can be impaired in the early postoperative phase after lung transplantation because the chronically untrained left ventricle is prone to fail. Thus, restrictive fluid management is pivotal to unload the left heart. In our institution, continuous renal replacement therapy is implemented liberally whenever a patient cannot be balanced negatively. It remains unclear whether such strategy impairs long-term kidney function.

METHODS

We retrospectively reviewed our institutional database for patients with idiopathic pulmonary arterial hypertension who underwent transplantation between 2000 and 2018. The impact of postoperative continuous renal replacement therapy on long-term outcomes was investigated using a linear mixed model and multivariable Cox regression.

RESULTS

A total of 87 idiopathic pulmonary arterial hypertension lung transplant recipients were included in this analysis. In 38 patients (43%), continuous renal replacement therapy was started in the early postoperative period for a median of 16 days (10-22). In this group, urine production significantly decreased and patients began to acquire a positive fluid balance; however, homeostatic functions of the kidney were still preserved at the time of continuous renal replacement therapy initiation. All patients were successfully weaned from continuous renal replacement therapy and fully recovered their kidney function at the time of hospital discharge. No difference in kidney function was found between continuous renal replacement therapy and noncontinuous renal replacement therapy in patients within 5 years.

CONCLUSIONS

Early implementation of continuous renal replacement therapy for perioperative volume management does not impair long-term kidney function in idiopathic pulmonary arterial hypertension lung transplant recipients. Our data suggest that such a strategy leads to excellent long-term outcomes.

Lung transplantation for idiopathic pulmonary arterial hypertension on intraoperative and postoperatively prolonged extracorporeal membrane oxygenation provides optimally controlled reperfusion and excellent outcome

OBJECTIVES

Lung transplantation for idiopathic pulmonary arterial hypertension has the highest reported postoperative mortality of all indications. Reasons lie in the complexity of treatment of these patients and the frequent occurrence of postoperative left ventricular failure. Transplantation on intraoperative extracorporeal membrane oxygenation support instead of cardiopulmonary bypass and even more the prolongation of extracorporeal membrane oxygenation into the postoperative period helps to overcome these problems. We reviewed our experience with this concept.

METHODS

All patients undergoing bilateral lung transplantation for idiopathic pulmonary arterial hypertension on intraoperative extracorporeal membrane oxygenation with or without prophylactic extracorporeal membrane oxygenation prolongation into the postoperative period between January 2000 and December 2014 were retrospectively analysed.

RESULTS

Forty-one patients entered the study. Venoarterial extracorporeal membrane oxygenation support was prolonged into the postoperative period for a median of 2.5 days (range 1–40). Ninety-day, 1-, 3- and 5-year survival rates for the patient collective were 92.7%, 90.2%, 87.4% and 87.4%, respectively. When compared with 31 patients with idiopathic pulmonary arterial hypertension transplanted in the same period of time without prolongation of extracorporeal membrane oxygenation into the postoperative period, the results compared favourably (83.9%, 77.4%, 77.4%, and 77.4%; P = 0.189). Furthermore, these results are among the best results ever reported for this particularly difficult patient population.

CONCLUSIONS

Bilateral lung transplantation for idiopathic pulmonary arterial hypertension with intraoperative venoarterial extracorporeal membrane oxygenation support seems to provide superior outcome compared with the results reported about the use of cardiopulmonary bypass. Prophylactic prolongation of venoarterial extracorporeal membrane oxygenation into the early postoperative period provides stable postoperative conditions and seems to further improve the results.

Surgical treatment of pulmonary hypertension: Lung transplantation

Pulmonary hypertension (PH) is a serious and progressive disorder that results in right ventricular dysfunction that lead to subsequent right heart failure and death. When untreated the median survival for these patients is 2.8 years. Over the past decade advances in disease specific medical therapy considerably changed the natural history. This is reflected in a threefold decrease in the number of patients undergoing lung transplantation for PH which used to be main stay of treatment. Despite the successful development of medical therapy lung transplant still remains the gold standard for patients who fail medical therapy. Referral for lung transplant is recommended when patients have a less than 2-3 years of predicted survival or in NYHA class III or IV. Both single and bilateral lung transplants have been successfully performed for PH but outcome analyses and survival comparisons generally favor a bilateral lung transplant.

Effect of pulmonary hypertension in patients with end-stage lung disease on posttransplantation outcomes

A subgroup of patients with end-stage lung disease develop secondary pulmonary hypertension (PH). PH results in worse prognosis in these patients. However, it is unclear if this effect prevails in the immediate- and long-term outcomes of these patients after lung transplantation (LT). The objective of this study was to evaluate the effect of pretransplantation PH on immediate- or long-term posttransplantation outcomes. A retrospective chart review of post-LT patients at Henry Ford Hospital from January 1995 through January 2008 was done. Patients were grouped by presence or absence of PH and were compared using chi-square or Fisher exact tests for categorical variables and t tests or Wilcoxon rank sum tests for continuous variables. Kaplan-Meier estimation was used to evaluate primary and secondary outcomes. Among the patients included in the study, 25 had PH. This group consisted mostly of females (68%). There was no difference in the indication or type of LT in the 2 groups. There was no statistically significant difference in freedom from bronchiolitis obliterans syndrome (BOS; P = .42), time to onset of BOS (P = .82), grade of BOS (P = .21), or cummulative acute rejection (CAR) score (P = .66). There was no difference in overall mortality at 3 and 5 years (P = .57) or time to death (P = .25). Number of A1 rejection episodes was the only significant predictor for BOS (P = .001). In conclusion, PH due to end-stage lung disease does not have any effect on early or late posttransplantation outcomes. There is predisposition for females with end-stage lung disease to develop secondary PH more so than males. The number of A1 rejections increases the likelihood of development of BOS. A larger multicenter study is needed to confirm the results of this pilot study.

Impact of secondary pulmonary hypertension on lung transplant outcome

INTRODUCTION

Secondary pulmonary hypertension (SPH), defined as a mean pulmonary artery pressure (PAM) greater than 25 mm Hg, complicates end-stage lung diseases of varying etiology. Although previous studies have suggested that SPH does not adversely affect outcome, no study has assessed the impact of the degree of SPH.

METHODS

A retrospective review of the lung transplant database was used to identify patients who underwent either single-lung (SLT) or bilateral lung transplantation (BLT) complicated by SPH. SPH patients were stratified into low SPH (PAM = 30-40 mm Hg) and high SPH (PAM > or = 40 mm Hg). Each group was further sub-categorized into SLT or BLT. Patients with a heart-lung transplant or primary pulmonary hypertension were excluded. Recipients without pulmonary hypertension transplanted over the same time were used as controls. Data are reported as controls vs low SPH vs high SPH.

RESULTS

One hundred-four patients received lung transplants between August 1998 and March 2003. There were 45 patients (18 men and 27 women) with SPH. Of these, 28 patients had low SPH, and 17 patients had high SPH. Forty-two patients (18 men and 24 women) without PH were the controls. There were no significant differences between groups except pre-operative oxygen dependence (81% vs 100% vs 94%, respectively) and use of CPB (28.6% vs 57.1% vs 64.7%, respectively). PAO2-PaO2 gradients and PaO2/FIO2 ratios were significantly worse in the high SPH group (116.2 vs 132.9 vs 186.3; p < 0.006) and (277.8 vs 234.3 vs 214.4; p < 0.026) respectively. There was no statistical difference in length of mechanical ventilation or duration of intensive care unit stay between groups. PAMs were significantly different pre-operatively (22.2 +/- 0.8 vs 34.0 +/- 0.6 vs 47.8 +/- 2.0; p < 0.001) and post-operatively (20.9 +/- 1.1 vs 23.7 +/- 1.3 vs 24.8 +/- 2.1; p < 0.001). There were no operative deaths. There were 3 early deaths in the control group, 1 in the low SPH group, and 3 in the high SPH group, none were related to pulmonary hypertension. Actuarial survival at 12, 24, and 48 months was not significantly different among the groups nor between SLT or BLT with SPH.

CONCLUSION

Although SPH increases the risk of reperfusion injury; survival is equivalent with mild or moderate pulmonary hypertension. Either SLT or BLT may be used in patients with SPH without compromising outcome. This has the added benefit of expanding the donor pool.

Surgical Treatments/Interventions for Pulmonary Arterial Hypertension

While considerable advances have been achieved in the medical treatment of pulmonary arterial hypertension (PAH) over the past decade, surgical and interventional approaches continue to have important roles in those patients for whom medical therapy is unavailable or has been unsuccessful. These techniques include pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension, thoracic transplantation, and atrial septostomy. This chapter will provide evidence-based recommendations for the selection and timing of surgical and interventional treatments of PAH for physicians involved in the care of these complex patients.

Lung transplantation for primary and secondary pulmonary hypertension

BACKGROUND

Single lung transplantation (SLT) and bilateral lung transplantation (BLT) are routinely performed in patients with primary pulmonary hypertension (PPH) and secondary pulmonary hypertension (SPH). It is unclear which procedure is preferable. We reviewed our experience with lung transplants for PPH and SPH to determine if any advantage exists with SLT or BLT for either PPH or SPH.

METHODS

We reviewed the outcomes of all lung transplants performed for PPH or SPH for 4.5 years (July 1995 to January 2000). Survival was reported by the Kaplan-Meier method, and log rank analysis was used to determine significance. Statistical analyses of clinical data were performed using analysis of variance and chi2 analysis.

RESULTS

A total of 57 recipients met criteria for pulmonary hypertension with a mean pulmonary artery pressure of greater than or equal to 30 mm Hg. There were 15 patients with PPH and 40 patients with SPH. There were 6 patients who had SLTs and 9 patients who had BLTs in the PPH group; and there were 9 patients who had SLTs and 21 patients who had BLTs in the SPH group. We found a survival advantage for PPH patients who underwent BLTs at all time points up to 4 years (100% vs 67%; p < or = 0.02). There was no clear advantage to SLTs or BLTs for SPH. At 4 years there was a trend toward improved survival with SLTs (91% vs 75%) in SPH patients with a mean pulmonary artery pressure less than or equal to 40 mm Hg (p < or = 0.11) with equivalent survival (80%) in patients with a mean pulmonary artery pressure greater than or equal to 40 mm Hg. There was also a trend toward improved survival in patients with a mean pulmonary artery pressure greater than or equal to 40 mm Hg (PPH and SPH) with BLTs (88% vs 62%; p = 0.19). The incidence of rejection, infection, and other complications was comparable between SLTs and BLTs in each group.

CONCLUSIONS

We believe that BLT is the procedure of choice for PPH. The procedure of choice is less clear for SPH. Patients with SPH and a mean pulmonary artery pressure greater than 40 mm Hg may benefit from a BLT and those with a mean pulmonary artery pressure less than or equal to 40 mm Hg may do better with an SLT; however, no clear advantage is seen.