Single-lung transplantation for pulmonary hypertension. Three-month hemodynamic follow-up

Medical treatment of primary pulmonary hypertension: a bridge to transplantation?

Primary pulmonary hypertension is a progressive disease with a mean survival of < 3 years from the time of diagnosis. Recent advances in the medical management have shown that some patients may have an extremely good outcome depending on the response to high doses of calcium antagonists. Anticoagulants are also associated with improved survival, and prostacyclin is showing great promise in patients who are refractory to conventional therapy. At the same time, lung transplantation has developed into a viable treatment option for patients who remain symptomatic and deteriorate on medical management. The role of the various medical treatment modalities, and the ideal timing of lung transplantation, is an issue that is continuing to evolve as improvements in all treatments develop. The cost and availability of the various treatments will likely affect the selection of treatments in individual patients as well.

Cardiopulmonary exercise testing following allogeneic lung transplantation for different underlying disease states

OBJECTIVES

To assess the exercise response to single lung transplantation in chronic airflow obstruction (CAO), idiopathic pulmonary fibrosis (IPF), and pulmonary vascular disease (PVD) vs double lung transplantation at well-defined time points after transplantation, and to define the change in exercise response in SLT and DLT over the first year after transplantation.

DESIGN

Prospective study.

SETTING

Tertiary referral hospital.

PATIENTS

Fourteen stable SLT recipients (6 with CAO, 4 with IPF, 4 with PVD) and 11 stable DLT recipients.

MEASUREMENTS

Spirometry, lung volumes, diffusion lung capacity for carbon monoxide (DLco) and MVV measured prior to exercise at 3 months (n = 25) then at 3-month intervals up to a maximum of 12 months post-transplantation (n = 18 [12 SLT and 6 DLT]). Symptom-limited cardiopulmonary exercise tests at same time points (n = 25 at 3 months, n = 18 [12 SLT and 6 DLT] at 3-month intervals up to 12 months). Breathlessness was estimated by visual analogue scale prior to exercise and at peak exercise.

RESULTS

At 3 months, FEV1 percent predicted was lower for SLT-CAO and SLT-IPF vs DLT (p < or = 0.05). Mean FEV1/FVC was lower for SLT-CAO vs all other groups (p < or = 0.05). The FVC, MVV, and DLco/VA were similar for all groups. The TLC and RV were higher for the SLT-CAO group compared with all others. The TLC was lower for SLT-PVD compared with DLT. Exercise responses were similar in all groups studied without a statistically significant difference in achieved VO2, work rate, O2 pulse, anaerobic threshold, heart rate response, respiratory rate, VE/MVV, and VT/VC. The change in O2 saturation during exercise was the least in recipients of DLT. Maximal achieved VO2 rose from 3 to 6 months after SLT but dropped by 9 to 12 months after transplantation. Maximal achieved VO2 trended up from 3 to 6 months after DLT but dropped by 9 to 12 months after transplantation. Maximal achieved work rate rose in both SLT and DLT from 3 to 9 to 12 months after transplantation. There was no significant difference in breathlessness at rest and peak exercise measured between recipients of SLT or DLT.

CONCLUSIONS

Minor differences in pulmonary function and change in O2 saturation occur between recipients of SLT and DLT during the first posttransplant year. These differences are most pronounced when comparing SLT-CAO with DLT. However, there is no significant difference in exercise capacity between SLT for CAO, IPF, PVD, and DLT. The rise in maximum achieved VO2 over the first 6 months after transplantation may reflect the effects of exercise training and should be taken into account when examining aerobic response after transplantation.

Impact of pulmonary hypertension on outcome after single-lung transplantation

Single lung transplantation for pulmonary hypertension (PH) remains a controversial therapy. We retrospectively studied 48 consecutive recipients of single-lung allografts to determine if preoperative PH was associated with increased mortality or morbidity. Recipients were divided into two groups; those who did have preoperative PH, defined as mean pulmonary arterial pressure less than or equal to 30 mm Hg (n = 29; group 1), and those recipients with PH who had a mean pulmonary arterial pressure greater than 30 mm Hg (n = 19; group II). Mean pulmonary arterial pressure and pulmonary vascular resistance decreased significantly after transplantation in recipients with PH. These values remained significantly higher as compared with those in recipients without pretransplantation PH. Postoperative pulmonary ventilation/perfusion scans demonstrated significant ventilation/perfusion mismatch in lung allografts with pretransplantation PH (p < 0.05). The mean duration of intensive care unit stay was significantly longer in recipients with PH. Although operative mortality was similar between the groups, preoperative PH was associated with significantly lower 1-year survival (53% versus 72%; p < 0.05) and New York Heart Association functional class (p < 0.05). We conclude that preoperative PH in single-lung transplant recipients is associated with significantly increased mortality, prolonged intensive care unit stay, and less symptomatic improvement. Thus, despite a shortage of donor organs, single-lung transplantation may be suboptimal therapy in patients with PH. Further study comparing single versus bilateral lung transplantation for PH is necessary.

Profile of paediatric patients with pulmonary hypertension judged by responsiveness to vasodilators

OBJECTIVE

To describe the demographic and haemodynamic variables of children presenting with primary pulmonary hypertension or pulmonary hypertension appearing or persisting after surgical correction of congenital heart defects and to assess the acute effect of vasodilator drugs on their pulmonary vascular bed.

DESIGN

Retrospective review.

SETTING

Paediatric cardiology department and intensive care unit of a large tertiary centre.

PATIENTS

Fourteen consecutive patients presenting with primary pulmonary hypertension (group 1) or pulmonary hypertension persisting or appearing late after complete surgical repair (group 2).

INTERVENTION

Baseline haemodynamic measurements were taken in room air at rest and repeated in 100% oxygen. With constant monitoring of heart rate and pulmonary and systemic arterial pressures, patients were given serial intravenous, sublingual, or oral incremental doses of vasodilators (mean 4.1 trials per patient). The maximum effect of the drug was charted.

MAIN OUTCOME MEASURES

A positive response to acute vasodilator tests was defined as a decrease in mean pulmonary or mean systemic arterial pressure > 15% with the mean pulmonary artery pressure not reaching the systemic level and either no change or an increase in mean systemic arterial pressure. Haemodynamic variables between groups (1 v 2, responders v non-responders, patients experiencing or not experiencing adverse effects to vasodilators) were compared by a two tailed unpaired Student's t test, and their survival curves were compared by the log rank statistic.

RESULTS

Groups are small and definitive conclusions are difficult to draw, but the baseline haemodynamic assessments were not significantly different between group 1 and 2 or between responders and non-responders to vasodilators. Patients experiencing adverse effects had a higher pulmonary vascular resistance (p = 0.04) and wedge pressure (p = 0.02) than those without adverse effects. Of the vasodilators used, tolazoline, hydralazine, salbutamol, phentolamine, and phenoxybenzamine were ineffective. A positive response was seen in five of 13 patients given oxygen, in one of eight given prostacyclin, four of 12 given nifedipine, four of eight given diltiazem, one of six given captopril, and two of seven given glyceryl trinitrate. Estimates of survival of the population with primary pulmonary hypertension were 37% at one year and 12% at 2.5 years. Survival was significantly shorter in the non-responders than in the responders (p = 0.005).

CONCLUSION

Children with primary pulmonary hypertension present to the cardiologist at a young age (five of eight were younger than 7 years) but with advanced pulmonary vascular disease and have a poor prognosis. 64% of group 1 and group 2 patients had a positive response to acute treatment with at least one vasodilator. Calcium channel blockers were the most effective agents. There was a positive response to drugs despite a negative response to acute treatment with oxygen. The survival of non-responders was shorter than that of the responders.

Echocardiographic characterization of the improvement in right ventricular function in patients with severe pulmonary hypertension after single-lung transplantation

OBJECTIVES

This study was designed to characterize immediate, early and long-term changes in right ventricular structure and function, as defined by two-dimensional and Doppler echocardiography, after single-lung transplantation in patients with severe pulmonary hypertension.

BACKGROUND

Single-lung transplantation has recently been shown to dramatically improve hemodynamics in patients with primary pulmonary hypertension who had unsuccessful medical therapy.

METHODS

Fourteen patients with severe pulmonary hypertension who underwent single-lung transplantation were studied with transthoracic and transesophageal two-dimensional and Doppler echocardiography. Right ventricular dimensions were measured in the apical four-chamber view. Right ventricular ejection and acceleration times and peak velocity of tricuspid regurgitation were measured by Doppler study. Results of right heart catheterization were available early (< 3 months) after transplantation in 10 of 13 patients and late after transplantation (6 months to 2 years) in 11 patients.

RESULTS

In the early posttransplantation studies, right ventricular dimensions decreased and fractional area change and ejection fraction increased in all patients, but right ventricular wall thickness did not change significantly. Tricuspid regurgitation lessened markedly in all patients. Long-term decreases in right ventricular dimension and improvement in systolic function were sustained. Right ventricular wall thickness significantly decreased compared with the early postoperative value (0.76 +/- 0.1 cm compared with 0.63 +/- 0.14 cm, p < 0.02).

CONCLUSIONS

Two-dimensional echocardiography demonstrates sustained improvement in right ventricular function after single-lung transplantation for severe pulmonary hypertension despite severe preoperative dysfunction.