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

Lung Transplantation for Pulmonary Artery Hypertension

This manuscript discusses the role of lung transplantation in patients with pulmonary hypertension. The indications and timing for referral to a transplant unit and timing for wait-listing for lung transplantation are discussed. The type of transplantation—isolated (single or double) lung transplantation and situations when combined heart and double lung transplantation is indicated—will be elaborated. Escalation of medical therapy with the need and timing for bridging therapies such as extracorporeal membrane oxygenation until an appropriate organ becomes available will be discussed. Challenges in the postoperative period, specific to lung transplantation for pulmonary artery hypertension, will be reviewed. The outcomes following lung transplantation will also be considered in greater detail.

Pulmonary Hypertension and Right Ventricular Failure: Lung Transplant Versus Heart-Lung Transplant

Pulmonary arterial hypertension is a highly morbid disease with limited treatment options that improve survival and currently the only curative treatment is transplantation. There is a small body of literature comparing the efficacy of lung and heart-lung transplantation in this population. The bulk of evidence suggests that most patients with severe right ventricular failure undergoing transplant will have recovery of right ventricular function after lung transplantation. Existing data suggest that, in the absence of complex congenital heart disease or significant left ventricular dysfunction, double-lung transplant is the surgical procedure of choice.

Right ventricular recovery after bilateral lung transplantation for pulmonary arterial hypertension†

OBJECTIVES

Pulmonary arterial hypertension (PAH) is a progressive and often fatal disease characterized by increased pulmonary vascular resistance (PVR) and right ventricular (RV) failure. End-stage PAH is often an indication for a lung transplant (LTX). Our goal was to study ventricular recovery using cardiac magnetic resonance imaging late after LTX.

METHODS

We studied 10 patients with PAH who underwent isolated bilateral LTX. RV and left ventricular (LV) volumes, function and mass were measured. In addition, the RV stroke volume/end-systolic ratio (SV/ESV), the LV eccentricity index, the RV/LV volume ratio, the area of the tricuspid valve annulus and the severity of tricuspid regurgitation (TR) were calculated.

RESULTS

The median age was 44 [30-54] years and the mean PVR was 1020 ± 435 dynes·s·cm - 5 . Six patients had ≥ moderate TR. After LTX, the RV ejection fraction increased from 32 to 64% ( P  < 0.001) and both RV volume (from 118 to 51 ml/m 2 , P  < 0.001) and RV mass (from 69 to 33 g/m 2 , P  < 0.001) decreased. The mean SV/ESV ratio increased from 0.5 to 1.9 ( P  < 0.001) and the LV mass increased from 55 to 61 g/m 2 ( P  = 0.005). There was a decrease in both the LV eccentricity index (from 2.8 to 1.1, P  < 0.001) and the RV/LV volume ratio (from 2.3 to 0.8, P  < 0.001). The area of the tricuspid valve annulus also decreased (from 9.8 to 4.6 cm 2 /m 2 , P  < 0.001); no patient had ≥ mild TR post-LTX.

CONCLUSIONS

Cardiac magnetic resonance imaging confirms ventricular recovery after isolated bilateral LTX for end-stage PAH.

Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison

BACKGROUND

Advanced heart failure treated with a left ventricular assist device is associated with a higher risk of right heart failure. Many advanced heart failures patients are treated with an ICD, a relative contraindication to MRI, prior to assist device placement. Given this limitation, left and right ventricular function for patients with an ICD is calculated using radionuclide angiography utilizing planar multigated acquisition (MUGA) and first pass radionuclide angiography (FPRNA), respectively. Given the availability of MRI protocols that can accommodate patients with ICDs, we have correlated the findings of ventricular functional analysis using radionuclide angiography to cardiac MRI, the reference standard for ventricle function calculation, to directly correlate calculated ejection fractions between these modalities, and to also assess agreement between available echocardiographic and hemodynamic parameters of right ventricular function.

METHODS

A retrospective review from January 2012 through May 2014 was performed to identify advanced heart failure patients who underwent both cardiac MRI and radionuclide angiography for ventricular functional analysis. Nine heart failure patients (8 men, 1 woman; mean age of 57.0 years) were identified. The average time between the cardiac MRI and radionuclide angiography exams was 38.9 days (range: 1 - 119 days). All patients undergoing cardiac MRI were scanned using an institutionally approved protocol for ICD with no device-related complications identified. A retrospective chart review of each patient for cardiomyopathy diagnosis, clinical follow-up, and echocardiogram and right heart catheterization performed during evaluation was also performed.

RESULTS

The 9 patients demonstrated a mean left ventricular ejection fraction (LVEF) using cardiac MRI of 20.7% (12 - 40%). Mean LVEF using MUGA was 22.6% (12 - 49%). The mean right ventricular ejection fraction (RVEF) utilizing cardiac MRI was 28.3% (16 - 43%), and the mean RVEF calculated by FPRNA was 32.6% (9 - 56%). The mean discrepancy for LVEF between cardiac MRI and MUGA was 4.1% (0 - 9%), and correlation of calculated LVEF using cardiac MRI and MUGA demonstrated an R of 0.9. The mean discrepancy for RVEF between cardiac MRI and FPRNA was 12.0% (range: 2 - 24%) with a moderate correlation (R = 0.5). The increased discrepancies for RV analysis were statistically significant using an unpaired t-test (t = 3.19, p = 0.0061). Echocardiogram parameters of RV function, including TAPSE and FAC, were for available for all 9 patients and agreement with cardiac MRI demonstrated a kappa statistic for TAPSE of 0.39 (95% CI of 0.06 - 0.72) and for FAC of 0.64 (95% of 0.21 - 1.00).

CONCLUSION

Heart failure patients are increasingly requiring left ventricular assist device placement; however, definitive evaluation of biventricular function is required due to the increased mortality rate associated with right heart failure after assist device placement. Our results suggest that FPRNA only has a moderate correlation with reference standard RVEFs calculated using cardiac MRI, which was similar to calculated agreements between cardiac MRI and echocardiographic parameters of right ventricular function. Given the need for identification of patients at risk for right heart failure, further studies are warranted to determine a more accurate estimate of RVEF for heart failure patients during pre-operative ventricular assist device planning.

Left Ventricular Dysfunction After Lung Transplantation for Pulmonary Arterial Hypertension

BACKGROUND

Lung transplantation (LT) is the final treatment option for patients with pulmonary arterial hypertension (PAH). Perioperative challenges after LT are unique and commonly include excessive bleeding, arrhythmias, and primary graft dysfunction. Transient left ventricular dysfunction (LVD) is a known postoperative complication, but not fully explored. We describe our experiences at a single institution.

METHODS

We reviewed our database for patients with PAH who underwent LT from July 2008 to July 2012. The data were analyzed for preoperative inotrope use, intravenous prostacyclin, cardiac catheterization, and imaging. Also measured were perioperative ischemic time, bypass time, primary graft dysfunction, ventilator days, length of stay, and mortality. LVD is defined as acute cardiopulmonary compromise (acute worsening of hypoxia with new bilateral infiltrates on imaging) with a drop in LV systolic function of 15% from baseline. We compared data between patients with LVD and without LVD.

RESULTS

Sixteen patients met the criteria, the majority of patients (10) with World Health Organization (WHO) group 1 PAH. Thirteen received intravenous prostacyclin therapy, and 6 required inotropes before surgery. Five patients (31%) developed LVD after transplantation. Average time to onset of LVD was 4.2 days. Preoperative vasopressors were required in 60% of those developing LVD. Patients with LVD had lower right and left ventricular ejection fraction with higher left ventricular end diastolic volume before surgery. All patients recovered from LVD within 4 months after LT.

CONCLUSIONS

LVD is a phenomenon observed mostly in patients with WHO group 1 PAH receiving LT. Prompt recognition and treatment of this condition reduced morbidity.

A randomized controlled trial comparing health and quality of life of lung transplant recipients following nurse and computer-based triage utilizing home spirometry monitoring

BACKGROUND

Lung transplantation is now a standard intervention for patients with advanced lung disease. Home monitoring of pulmonary function and symptoms has been used to follow the progress of lung transplant recipients in an effort to improve care and clinical status. The study objective was to determine the relative performance of a computer-based Bayesian algorithm compared with a manual nurse decision process for triaging clinical intervention in lung transplant recipients participating in a home monitoring program.

MATERIALS AND METHODS

This randomized controlled trial had 65 lung transplant recipients assigned to either the Bayesian or nurse triage study arm. Subjects monitored and transmitted spirometry and respiratory symptoms daily to the data center using an electronic spirometer/diary device. Subjects completed the Short Form-36 (SF-36) survey at baseline and after 1 year. End points were change from baseline after 1 year in forced expiratory volume at 1 s (FEV1) and quality of life (SF-36 scales) within and between each study arm.

RESULTS

There were no statistically significant differences between groups in FEV1 or SF-36 scales at baseline or after 1 year.: Results were comparable between nurse and Bayesian system for detecting changes in spirometry and symptoms, providing support for using computer-based triage support systems as remote monitoring triage programs become more widely available.

CONCLUSIONS

The feasibility of monitoring critical patient data with a computer-based decision system is especially important given the likely economic constraints on the growth in the nurse workforce capable of providing these early detection triage services.

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.

Pulmonary hypertension before first and second lung transplantation

BACKGROUND

Pulmonary hypertension (PH) is frequently encountered in patients with advanced lung disease before the first and second lung transplantation. We sought to determine whether there is any relationship between pulmonary hemodynamics obtained before first and second lung transplantation. We also assessed whether PH has prognostic implications in lung transplant patients going for second transplantation.

METHODS

We included consecutive adult (16-yr-old or older) patients who underwent lung re-transplantation, between 1997 and 2009, and had right heart catheterization before their first and second lung transplantation.

RESULTS

Eighteen patients were included in the study. Age at first transplantation was 50.4 (SD 10.4) yr, and bronchiolitis obliterans syndrome (BOS) in the transplanted lung was the only indication for re-transplantation. PH was observed in 39% of the patients before the first lung transplant and in 56% of the subjects before re-transplantation (p = 0.91). Pre-capillary PH was present in 28% (n = 5) and 33% (n = 6) of the patients before first and second lung transplantation, respectively. None of the hemodynamic variables obtained before the first transplant predicted the development of PH before re-transplantation. PH before re-transplantation did not predict survival or development of BOS after re-transplantation.

CONCLUSIONS

PH before initial lung transplantation did not predict the development of PH before the second transplantation. In our cohort, PH before second lung transplantation did not predict outcomes after re-transplantation.

New approaches to the treatment of pulmonary hypertension: from bench to bedside

Pulmonary hypertension (PH) is a severe, life-threatening disease for which there are no effective curative therapies. A diverse group of agents such as prostacyclins, endothelin antagonists, phosphodiesterase inhibitors, calcium channel blockers, diuretics, inotropic agents, and anticoagulants are used to treat PH; however, none of these agents have a marked effect upon survival. Among the new agents that promise treatment of PH are rho-kinase inhibitors and soluble guanylate cyclase stimulators. Although these new classes of agents have beneficial effects in experimental animal models and clinical studies, they are not selective in their actions on the pulmonary vascular bed. This manuscript reviews the actions of rho-kinase inhibitors and soluble guanylate cyclase stimulators on the pulmonary vascular bed. It is our hypothesis that these new agents may be more effective than current therapies in the treatment of PH. Moreover, new methods in the delivery of these agents to the lung need to be developed so that their main effects will be exerted in the pulmonary vascular bed and their systemic effects can be minimized or avoided.

Activation of apoptotic pathways in experimental acute afterload-induced right ventricular failure

OBJECTIVE

The pathobiology of persistent right ventricular failure observed after an acute increase in right ventricular afterload remains incompletely understood. We hypothesized that persistent right ventricular dysfunction might be related to activation of apoptotic pathways.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

University research laboratory.

SUBJECTS

Mongrel dogs.

INTERVENTIONS

Fourteen anesthetized dogs were randomized to a transient 90-min pulmonary artery constriction operation to induce persistent right ventricular failure or to a sham operation followed 30 mins later by hemodynamic measurements and sampling of cardiac tissue.

MEASUREMENTS AND MAIN RESULTS

We evaluated effective arterial elastance to estimate right ventricular afterload and end-systolic elastance to estimate right ventricular contractility. Transient increase in pulmonary artery pressure persistently increased effective arterial elastance from 0.75 +/- 0.08 to 1.37 +/- 0.18 mm Hg/mL and decreased end-systolic elastance from 1.06 +/- 0.09 to 0.49 +/- 0.09 mm Hg/mL, end-systolic elastance/effective arterial elastance from 1.44 +/- 0.06 to 0.34 +/- 0.03, and cardiac output from 3.78 +/- 0.16 to 1.46 +/- 0.10 L/min, indicating right ventricular failure. At the pathobiologic level, we assessed apoptosis by real-time quantitative polymerase chain reaction, Western blotting, enzyme-linked immunosorbent assay, and immunohistochemistry. As compared with the sham-operated group, and with the left ventricle in animals with persistent right ventricular failure, there were decreased right ventricular and septal expressions of Bcl-2 with no changes in expressions of Bax, resulting in an increased Bax/Bcl-2 ratio. Right ventricular and septal Bcl-XL, and right ventricular Bcl-w gene expressions were decreased as compared with the sham-operated group, whereas Bak gene expression did not change. There were activations of right ventricular caspases-8 and -9 and of right ventricular and septal caspase-3. Diffuse right ventricular and septal apoptosis was confirmed by terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. There were also increased right ventricular and septal protein expressions of tumor necrosis factor-alpha.

CONCLUSIONS

Acute afterload-induced persistent right ventricular failure appears to be related to an early activation of apoptotic pathways and to a local overexpression of tumor necrosis factor-alpha, a proinflammatory cytokine.

Lung transplantation for pulmonary hypertension in children

Lung and heart-lung transplantation are accepted treatments for children with end-stage pulmonary vascular disease. This is a review of the current literature and our own experience with lung and heart-lung transplantation for children with pulmonary hypertension of a variety of causes. I reviewed the pertinent literature and our lung transplant database to acquire information and data regarding this subject. The patients include those at St. Louis Children's Hospital as well as those reported from other institutions. The major operative complications include those related to the surgical procedure itself (vascular and airway anastomotic stenoses) and those related to graft dysfunction. The 3- and 5-yr survival is approximately 60% and 50%, respectively, for children undergoing lung transplantation for pulmonary hypertension.Although these survival statistics are somewhat poor, transplantation remains the only viable alternative for children with end-stage pulmonary vascular disease failing to respond to medical therapy.

Adrenomedullin in the treatment of pulmonary hypertension

Adrenomedullin (AM) is a potent, long-lasting pulmonary vasodilator peptide. Plasma AM level is elevated in patients with primary pulmonary hypertension (PPH), and circulating AM is partially metabolized in the lungs. These findings suggest that AM plays an important role in the regulation of pulmonary vascular tone and vascular remodeling. We have demonstrated the effects of three types of AM delivery systems: intravenous administration, inhalation, and cell-based gene transfer. Despite endogenous production of AM, intravenously administered AM at a pharmacologic level decreased pulmonary vascular resistance in patients with PPH. Inhalation of AM improved hemodynamics with pulmonary selectivity and exercise capacity in patients with PPH. Cell-based AM gene transfer ameliorated pulmonary hypertension rats. These results suggest that additional administration of AM may be effective in patients with pulmonary hypertension. AM may be a promising endogenous peptide for the treatment of pulmonary hypertension.

Interventional and surgical modalities of treatment for pulmonary arterial hypertension

Beyond medical therapy, different interventional and surgical approaches exist for treatment of pulmonary arterial hypertension (PAH). Atrial septostomy has been applied in patients with lack of response to medical therapy in the absence of other surgical treatment options. With growing experience, procedure-related death rates have been reduced to 5.4%, and the most suitable patient group has been identified among patients with a mean right atrial pressure between 10 and 20 mm Hg. Pulmonary endarterectomy is the accepted form of treatment for patients with chronic thromboembolic pulmonary hypertension. Establishing the diagnosis and the classification of the type of lesions by pulmonary angiography is crucial for optimal patient selection. Perioperative mortality rates have been reduced to <10% in experienced centers, and the hemodynamic improvement is dramatic and sustained. Lung and heart-lung transplantation remains the procedure of choice for patients unsuitable for other treatment modalities. Timing of the procedure is difficult because waiting times vary between centers and usually are in a high range. Early referral of patients unresponsive to other treatment forms is therefore of importance to avoid transplantation of patients with established significant comorbidity. The survival rate during the first five years after transplantation for PAH is intermediate among the lung diseases, lower than chronic obstructive pulmonary disease but higher than idiopathic pulmonary fibrosis.

Treatment of pulmonary arterial hypertension: a preliminary decision analysis

STUDY OBJECTIVE

New therapies for pulmonary arterial hypertension (PAH) improve functional status, quality of life (QOL), and survival. Clinicians must chose between very different therapies without the availability of comparison studies. We constructed a "virtual" clinical trial to help inform these treatment choices.

DESIGN

We compare key outcomes related to survival, costs, and QOL using a Markov-type decision model to estimate the expected outcomes and costs for PAH patients treated for 1 year with bosentan and treprostinil compared to patients treated with epoprostenol, as well as patients treated with bosentan compared to those treated with treprostinil. The allowed transitions in the model were between World Health Organization functional class I to IV and death. Transition probabilities were based on observed transitions for bosentan. Treatment effect was estimated using 6-min walk data for treprostinil and epoprostenol. Utilities were calculated from estimated EuroQol health states. Cost was estimated from average wholesale price and Medicare reimbursement data. The effects of changing values of input variables on the key outcomes were calculated.

RESULTS

Treatment with bosentan compared to treatment with either epoprostenol or treprostinil was less costly and resulted in a greater gain in quality-adjusted life years (QALYs). Conversely, treprostinil was significantly more expensive than epoprostenol, without an appreciable gain in QALYs. These findings were not substantially affected by the reasonable adjustments of transition probabilities, utility values, or tachyphylaxis to epoprostenol.

CONCLUSION

Treatment with bosentan is more cost-effective than treatment with either treprostinil or epoprostenol. In addition, a net improvement in quality-adjusted survival may be expected.

Right atrial size and tricuspid regurgitation severity predict mortality or transplantation in primary pulmonary hypertension

Primary pulmonary hypertension (PPH) is a fatal illness. In advanced stages only transplantation is able to increase survival. Echocardiography is useful for the assessment of these patients, but there is limited information about its prognostic value. With this goal, 25 consecutive patients, age: 36.7 +/- 12.7 years, were studied and followed up for a mean period of 29 months (range: 0.2-84). Eleven echocardiographic parameters of cardiac anatomy, function, and hemodynamics were assessed. Age and sex were also analyzed. Death and heart-lung transplantation were considered end-points. Thirteen events (Death: 8; transplantation: 5) occurred in the follow-up (11 of 13 in the first year). Kaplan-Meier estimated survival free from transplantation at 5 years was 40% (95% CI: 23%-70%). In the univariate analysis, RAA (HR: 1.1, P =.0004), TR (HR: 2.7, P =.02), and RVET (HR: 0.98, P =.02) showed statistically significant relation with survival free from transplantation. Multivariate analysis showed that RAS (HR: 1.10, 95% CI: 1.04-1.17, P =.001) and TR (HR: 2.52, 95% CI: 1.01-6.3, P =.047) were independent risk factors of transplantation and death. The use of these findings on the management of patients with PPH should be tested in larger studies.

Current management of primary pulmonary hypertension

Primary pulmonary hypertension (PPH) is a rare disorder of the lung vasculature characterised by an increase in pulmonary artery pressure. Although the aetiology of this disease remains unknown, knowledge of the pathophysiology of the disease has advanced considerably. Diagnosis of PPH is largely by exclusion. The clinical symptoms associated with PPH are aspecific and similar to those seen in other cardiovascular and pulmonary diseases. Electrocardiography, echocardiography, pulmonary function tests, and a lung perfusion scan are necessary to exclude secondary forms of pulmonary hypertension and also help to confirm the diagnosis of PPH. A definite diagnosis of PPH is established by right-heart catheterisation which gives a precise measure of the blood pressure in the right side of the heart and the pulmonary artery, right ventricular function and cardiac output. Once a diagnosis of PPH is established, treatment involving drug therapy or surgery is commenced on the basis of the New York Heart Association functional class. Conventional treatment consists of lifetime administration of anticoagulants, oxygen, diuretics, and digoxin. Vasodilator therapy with calcium channel antagonists is indicated in patients who are 'vasoreactive' to acute vasodilator challenge as assessed by right-heart catheterisation. Promising results are obtained by continuous intravenous administration of epoprostenol (prostacyclin). Newer therapies for PPH include prostacyclin analogues, endothelin receptor antagonists, nitric oxide, phosphodiesterase-5 inhibitors, elastase inhibitors, and gene therapy. Surgical treatment consists of atrial septostomy, thromboendarterectomy, and lung or heart-lung transplantation.

Lung transplantation for primary pulmonary hypertension

Recent progress in medical therapies has diminished the role of transplantation in the management of PPH during the past decade. Drug therapy is not effective in some patients, responses to therapy are not sustained over time in others, and drug side effects eventually limit the benefits of treatment in a few more. Lung transplantation therefore ultimately is the only alternative for patients whose PPH is severe and cannot be managed medically. Choosing the right patient as a transplant candidate and the right time to make the initial referral to a transplant center are the crucial initial steps in the transplantation process, and the long waiting time before transplantation must be integrated into this decision. The outcome of lung and heart-lung transplantation for PHH has been good but sobering. Functional recovery has been excellent, but long-term survival results have been limited by the high prevalence of chronic allograft rejection.

The effects of single lung transplantation in rats with monocrotaline-induced pulmonary hypertension

Acute haemodynamic change after single lung transplantation for primary pulmonary hypertension was evaluated using a rat transplantation model. Inbred Fisher 344 rats were administered with 40 mg/kg monocrotaline in order to induce pulmonary hypertension. The rats whose mean pulmonary arterial pressure (PAP) was over 30.0 mm Hg received a left lung isograft from a normal donor after right heart catheterization. In the control group, PAP increased after single lung transplantation. On the other hand, in the pulmonary hypertensive group, PAP was significantly decreased 60 min after the transplantation, but 3 and 6 h after the transplantation, the PAP significantly increased again. On the day after the operation, it again decreased significantly. Left-to-right lung blood flow ratio was significantly increased in rats with pulmonary hypertension compared to rats with normal pulmonary pressure on both the 1st and 3rd postoperative days. The oedema of the grafted lung was more severe in the pulmonary hypertensive group than in the control group in the acute phase. In conclusion, single lung transplantation for pulmonary hypertension shifted pulmonary blood perfusion to the grafted lung and this shift made pulmonary oedema of the grafts more severe in the acute phase. These oedematous changes, which were more pronounced in the grafts in the pulmonary hypertensive rats, might have contributed to the transient rise in PAP in those rats after single lung transplantation.

Pulmonary hypertension update

Research into the causes and treatment of primary pulmonary hypertension (PPH) has provided new hope for this disease. This article reviews recent developments in its pathogenesis, classification, and treatment. An approach to diagnosing the patient with pulmonary hypertension also is outlined.

Atrial Septal Defect

The 1990s have seen considerable growth in our knowledge of outcomes in patients with atrial septal defect (ASD), improved techniques for imaging and diagnosing ASD, and advances in the treatment of ASD. Exciting new surgical procedures, such as minimally invasive surgery, the Cox-Maze procedure for patients with atrial fibrillation, and lung transplantation for patients with severe pulmonary artery hypertension, are now available. In my opinion, echocardiography is the procedure of choice for the diagnosis and characterization of ASD. Children and adults with ASD should undergo surgical repair unless there are contraindications. Surgical repair "early" in life prolongs survival and may prevent atrial fibrillation. Surgical repair in "older" adults prolongs survival and alleviates symptoms but will not abolish sustained or paroxysmal atrial fibrillation. Patients with ASD and atrial fibrillation (sustained or paroxysmal) should undergo surgical repair of ASD and a Cox-Maze procedure.

Effect of orally active prostacyclin analogue on survival of outpatients with primary pulmonary hypertension

OBJECTIVES

This study sought to investigate the effect of beraprost sodium (BPS), an orally active prostacyclin analogue, on the survival of outpatients with primary pulmonary hypertension (PPH).

BACKGROUND

Continuous intravenous administration of epoprostenol (prostacyclin) has been shown to improve survival in PPH. However, the effect of oral BPS on survival in PPH remains unknown.

METHODS

Fifty-eight consecutive patients with PPH who could be discharged after the first diagnostic catheterization for PPH were retrospectively divided into two groups: patients treated with BPS (BPS group, n = 24) and those without BPS (conventional group, n = 34). The baseline demographic and hemodynamic data did not significantly differ between the two.

RESULTS

Twenty-seven patients died of cardiopulmonary causes in the conventional group during a mean follow-up period of 44 +/- 45 months. In contrast, only 4 patients died of cardiopulmonary causes in the BPS group during a mean follow-up period of 30 +/- 20 months. In a subsample (n = 15) of patients in the BPS group, mean pulmonary arterial pressure and total pulmonary resistance significantly decreased, respectively, by 13% and 25% during a mean follow-up period of 53 days. Among the variables previously known to be associated with the mortality in PPH, the absence of BPS therapy and the reduced cardiac output were independently related to the mortality by a multivariate Cox proportional hazards regression analysis (both p < 0.05). The Kaplan-Meier survival curves demonstrated that the one-, two- and three-year survival rates for the BPS group were 96%, 86% and 76%, respectively, as compared with 77%, 47% and 44%, respectively, in the conventional group (log-rank test, p < 0.05).

CONCLUSIONS

The oral administration of BPS may have beneficial effects on the survival of outpatients with PPH as compared with conventional therapy alone.

The current status of lung transplantation: a nursing perspective

Since the first lung transplantation was attempted in 1963, the use of the procedure has gradually increased. The first successful operation was performed in 1983, and during the past decade the number of lung transplantations and heart-lung transplantations has increased rapidly, with 75% of recipients surviving past the first year. Chronic rejection is the greatest obstacle to long-term survival. In this article, a brief history of lung transplantation is provided. Recipient selection criteria are reviewed, together with the listing process and donor organ criteria. Recommendations for care of patients before and after lung transplantation are outlined, with a description of the postoperative course, including complications, pain control, rehabilitation, discharge procedures, and outpatient treatment.

Assessment of left ventricular diastolic function after single lung transplantation in patients with severe pulmonary hypertension

OBJECTIVES

This study was designed to observe left ventricular filling by Doppler echocardiography before and after single lung transplantation in patients with severe pulmonary hypertension.

BACKGROUND

Right ventricular pressure overload causes the deformation of the left ventricle by septal flattening toward its cavity, which may result in impaired left ventricular early filling. Recent studies have demonstrated the ability of single lung transplantation to restore right ventricular function in patients with severe pulmonary hypertension. However, changes in left ventricular filling after single lung transplantation have not been well studied.

METHODS

We performed Doppler echocardiography in nine patients with severe pulmonary hypertension before, early (<3 months), and late (>1 year) after single lung transplantation. The study group consisted of eight female patients and one male patient with mean age of 32 years (range, 15 to 48 years). Six patients were diagnosed as having primary pulmonary hypertension and three as having secondary pulmonary hypertension. Nine age-matched normal subjects served as a control group. Doppler measurements included the following: transmitral flow early (E) and atrial (A) velocities, integrals (Ei and Ai), and left ventricular isovolumic relaxation time. The ratio of E/A and atrial filling fraction (Ai/Ei+Ai, AFF) were also determined. Left ventricular geometry was assessed from mid-short axis view with a circular shape factor (CSF).

RESULTS

Early after lung transplantation, the left ventricular geometry became more circular with CSF (mean+/-SD) increasing from 0.63+/-0.09 to 0.88+/-0.05 (p<0.05). However, impaired early filling persisted in the patient group (E/A 0.7+/-0.1 vs preoperative 0.6+/-0.1, AFF 0.61+/-0.1 vs 0.64+/-0.1; both p=not significant). One year later, the left ventricular filling had returned to normal range with E/A 1.4+/-0.6 and AFF 0.35+/-0.1.

CONCLUSIONS

This study observed that the impaired left ventricular early filling persisted shortly after single lung transplantation in patients with severe pulmonary hypertension, despite findings that left ventricular geometry was restored earlier after reversal of pulmonary hypertension. The abnormal filling pattern appeared to be resolved 1 year later. The findings suggest the impaired early filling may be caused by intrinsic left ventricular abnormalities other than ventricular interaction in these patients.

The impact of bronchiolitis obliterans on late morbidity and mortality after single and bilateral lung transplantation for pulmonary hypertension

Primary pulmonary hypertension (PPH) is a rare cardiovascular disease with a variable course; however, in general, its prognosis is poor. Among the various treatment options available, transplantation (initially heart-lung transplantation, and later isolated single or bilateral lung transplantation) has become an accepted modality. Heart-lung transplantation is necessary only in a minority of patients because right ventricular recovery has been gratifying after isolated lung transplantation. Furthermore, the scarcity of suitable donor organs mandates the achievement of the maximal number of heart and lung transplants from the limited donor pool. Available published data show that both single and bilateral lung transplantation are suitable alternatives for the majority of patients with pulmonary hypertension. Bronchiolitis obliterans syndrome (BOS), the main cause of late mortality and morbidity in lung transplant recipients, affects pulmonary hypertensive patients as it does other recipient subgroups. The available data regarding the impact of BOS on single versus bilateral lung recipients with pulmonary hypertension are somewhat scanty. Although some have suggested that BOS is more prevalent among PPH recipients, this is not uniformly supported through the literature. Other reports have documented severe ventilation-perfusion imbalance associated with graft dysfunction secondary to BOS in single lung transplant recipients with PPH. Despite this, there are no available data to document a significant survival benefit for PPH patients receiving bilateral versus single lung transplantation. Our own transplantation experience at Washington University in St. Louis with pulmonary hypertension shows a trend toward better survival in bilateral lung recipients, although this difference is not significant. Ultimately, both single and bilateral lung replacement seem to be satisfactory transplant options in PPH. Both recipient groups are affected by BOS, and longer follow-up of larger numbers of patients may document superior survival and functional outcome with bilateral lung replacement.

Lung transplantation for pulmonary hypertension: patient selection and maintenance therapy while awaiting transplantation

Although lung transplantation is considered a definitive treatment of patients with advanced pulmonary vascular disease and pulmonary hypertension, advances in the success of the medical management of patients with pulmonary hypertension make it less clear as to when to refer a patient for transplantation. Coumadin anticoagulation is associated with improved survival in all patients, and calcium channel blockers therapy with improved survival in very select patients. Chronic prostacyclin represents a newer therapy that seems to have a dramatic impact on patients' functional class and survival. As improvements continue in the medical management in pulmonary hypertension, and in survival of patients undergoing lung transplantation, the guidelines for patient selection should be constantly evolving.

Pulmonary hemodynamics and blood flow characteristics in chronic pulmonary hypertension

BACKGROUND

Lung transplantation is now an acceptable form of therapy for pulmonary hypertension, but controversy remains regarding the most appropriate surgical procedure. In this study, the changes in pulmonary vascular mechanics occurring in the setting of pulmonary hypertension were investigated using an adult canine model of monocrotaline pyrrole-induced pulmonary hypertension.

METHODS

Animals underwent pulmonary artery catheterization to measure right heart pressures before and 8 weeks after injection of either 3 mg/kg of monocrotaline pyrrole (n = 8) or placebo (n = 8). Eight weeks after injection, hearts underwent instrumentation with an ultrasonic flow probe and micromanometers. Harmonic derivation of functional data was achieved with Fourier analysis.

RESULTS

Significant increases in mean pulmonary artery pressure and pulmonary vascular resistance were observed after monocrotaline pyrrole injection. There was no significant difference in pulmonary blood flow. However, significant increases in input resistance and right ventricular hydraulic power with significant decreases in transpulmonary efficiency were observed.

CONCLUSIONS

Pulmonary hypertension causes significant alterations in pulmonary hemodynamics. Pulmonary blood flow is maintained by a significant increase in total power but with a significant decrease in transpulmonary efficiency. This adult canine model of pulmonary hypertension provides a useful means by which to evaluate surgical options of lung transplantation for improving pulmonary hemodynamics in the setting of chronic pulmonary hypertension.

Graft damage after a single lung transplantation for pulmonary hypertension in a rat model

The hemodynamic effect and degree of damage in grafts of single lung transplants for pulmonary hypertension were studied in rats with monocrotaline-induced pulmonary hypertension. Inbred male Lewis rats (weight 200-230 g) were divided into two groups. Group 1 (control group, n = 16) underwent isogenic left lung transplantation, while group 2 (n = 15) received an intravenous administration of monocrotaline (80 mg/kg i.v.) and underwent isogenic left single lung transplantation 3 week later. Hemodynamic evaluations were performed prior to transplantation, at 1 h postoperatively, and on days 3 and 7 after transplantation. Mean pulmonary arterial pressure (mPAP) rapidly declined after transplantation in group 2, from 39.3 +/- 8.7 mmHg to 18.5 +/- 3.0 mmHg 1 h after transplantation, and remained stable on day 7 after transplantation. No significant difference in the mPAP between the two groups was observed after transplantation. The extravascular lung water volume (ELWV: dry/wet ratio) in the right lung of group 2 significantly increased on day 3 (0.86 +/- 0.02) (P < 0.01), and subsequently decreased to control levels on day 7 (0.83 +/- 0.02). There was no significant difference in the ELWV in the grafted lungs between the two groups (0.84 +/- 0.03 vs 0.86 +/- 0.04), but there was tendency toward an increase in ELWV in group 2 on days 3 and 7. These data thus demonstrated that a hemodynamic improvement was obtained by single lung transplantation; however the degree of graft damage was remarkable in the pulmonary hypertension group.

Variability of right ventricular functional recovery after lung transplantation

BACKGROUND

The purpose of this study was to assess by echocardiography the effects of lung transplantation on recovery of right ventricular (RV) function in patients with preoperative RV dysfunction.

METHODS

Fourteen (20%) of 71 lung transplant recipients were identified by echocardiography as manifesting abnormal RV function before lung transplantation. These 14 patients were selected for follow-up echocardiographic study 8 months after transplantation.

RESULTS

RV function improved significantly in the study group. Mean RV end-diastolic area decreased from 26.8 +/- 7.9 cm2 to 20.1 +/- 4.7 cm2 (P < 0.01); mean RV end-systolic area decreased from 21.5 +/- 6.8 cm2 to 13.1 +/- 4.2 (P < 0.01); and mean RV fractional area change (FAC) increased from 20.4 +/- 3.3% to 35.8 +/- 8.9% (P < 0.001). A subgroup of four patients, however, exhibited no change in RV function. Patients who achieved improvement in RV function tended to be younger, had shorter duration of disease before transplantation, and had higher pulmonary arterial (PA) pressures before transplantation (PA systolic, 89 +/- 28 mmHg vs. 38 +/- 11 mmHg, P < 0.001; PA diastolic, 42 +/- 11 mmHg vs. 19 +/- 3 mmHg, P < 0.002). Each of the eight patients with primary pulmonary hypertension exhibited improvement in RV function (mean delta FAC +20.6 +/- 5.9%), while two of three patients with emphysema and both patients with idiopathic pulmonary fibrosis failed to achieve improvement in RV function (mean delta FAC +2.3 +/- 1.2%).

CONCLUSIONS

Improvement of RV function assessed by echocardiography occurs after lung transplantation, even in patients with severe preoperative RV dysfunction. However, the degree of improvement is variable and may depend on the degree of RV after-load reduction and the presence or absence of intrinsic myocardial disease. RV ejection parameters do not distinguish between these two possibilities.

Right ventricular pathology in chronic pulmonary hypertension

Right ventricular free wall biopsy specimens in 40 patients undergoing surgery for relief of chronic thromboembolic pulmonary hypertension were normal in 5%, disclosed only myocyte hypertrophy in 80%, mild focal fibrosis in 12.5%, and myocarditis in 2.5%. There was no relation between postsurgical functional or hemodynamic outcomes and the presence of focal fibrosis.

Euro-Collins solution exacerbates lung injury in the setting of high-flow reperfusion

Single-lung transplantation has been abandoned for the treatment of pulmonary hypertension by many centers because of overperfusion of the graft following implantation. Euro-Collins solution is currently used for lung preservation despite the vasoconstrictive effect of this intracellular-type solution. We hypothesized that high-flow reperfusion, alone or in combination with Euro-Collins-induced vasoconstriction, may cause lung dysfunction. Twenty-eight New Zealand White rabbit lungs were harvested and studied in an isolated, blood-perfused model of lung function after 4 hours of cold ischemia. Control lungs were preserved with 50 ml/kg cold saline solution flush and reperfused at either normal flow (60 ml/min) or high flow (120 ml/min). Experimental lungs were preserved with 50 ml/kg cold Euro-Collins solution and reperfused at normal or high flow rates. The arteriovenous oxygen gradient at the end of the 30-minute reperfusion period was significantly lower in the high-flow versus the low-flow experimental group (31.1 +/- 4.2 vs 130.6 +/- 41.6 mm Hg, p < 0.05). The pulmonary vascular resistance was increased in the high-flow groups and the experimental groups, with a statistically significant difference between low-flow experimental and control groups (64374.4 +/- 5722.6 vs 37041.5 +/- 2110.9 dynes x sec x cm(-5), p < 0.001). The percentage decrease in dynamic airway compliance in the high-flow experimental group was markedly different from that in the high-flow control group (-51% +/- 13.3% vs -10.15% +/- 3.4%, p < 0.05). Similarly, the wet/dry ratio of the lungs in the high-flow experimental group (13.92 +/- 2.32) was significantly greater than that in the low-flow experimental group (6.27 +/- 0.19, p < 0.01) and than that in the high-flow control group (5.88 +/- 0.23, p < 0.001). These data demonstrate that high-flow reperfusion and preservation with Euro-Collins solution are deleterious to lung function, both individually and in combination, in an ex vivo rabbit lung model. Lung preservation with Euro-Collins solution may not be optimal when high-flow reperfusion is anticipated, as in the setting of unilateral lung transplantation for pulmonary hypertension.

Mid-term results of pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension

BACKGROUND

In patients with chronic thromboembolic pulmonary hypertension, acute and striking decreases of pulmonary artery pressures and vascular resistance can be achieved by pulmonary thromboendarterectomy. In this study, the long-term effects of pulmonary thromboendarterectomy on hemodynamic indices and right ventricular function were investigated.

METHODS

Sixty-five patients (31 women and 34 men; mean age, 47 +/- 17 years; range, 19 to 69 years; New York Heart Association [NYHA] functional class II, n = 3; class III, n = 38; class IV, n = 24) were reassessed 13 to 48 months (mean, 27 months) after pulmonary thromboendarterectomy. Measurements are reported as mean +/- standard deviation.

RESULTS

All patients reported a significant improvement of symptoms: 46 patients were in NYHA functional class I, 16 patients in class II, and 3 patients in class III. Mean pulmonary vascular resistance was significantly reduced compared with preoperative and postoperative values (preoperative: 1,015 +/- 454 dynes.s.cm-5; postoperative: 322 +/- 154 dynes.s.cm-5; follow-up: 198 +/- 72 dynes.s.cm-5; p < 0.001 versus preoperative; p < 0.025 versus postoperative). Concomitantly, cardiac index was significantly increased compared with preoperative values (preoperative: 2.0 +/- 0.7 L.min-1.m-2; follow-up: 2.9 +/- 0.5 L.min-1.m-2; p < 0.001). Significant reductions of right ventricular dimensions and recovery of right ventricular function could be demonstrated radiologically and echocardiographically. In 3 patients (preoperative NYHA class IV, NYHA class III at follow-up) with proven coagulation abnormalities, pulmonary vascular resistance was moderately increased at follow-up compared with postoperative measurements.

CONCLUSIONS

In patients with chronic thromboembolic pulmonary hypertension, a persistent decrease of pulmonary vascular resistance and improvement of right ventricular function and NYHA functional status can be achieved by pulmonary thromboendarterectomy.

A comparison of continuous intravenous epoprostenol (prostacyclin) with conventional therapy for primary pulmonary hypertension

BACKGROUND

Primary pulmonary hypertension is a progressive disease for which no treatment has been shown in a prospective, randomized trial to improve survival.

METHODS

We conducted a 12-week prospective, randomized, multicenter open trial comparing the effects of the continuous intravenous infusion of epoprostenol (formerly called prostacyclin) plus conventional therapy with those of conventional therapy alone in 81 patients with severe primary pulmonary hypertension (New York Heart Association functional class III or IV).

RESULTS

Exercise capacity was improved in the 41 patients treated with epoprostenol (median distance walked in six minutes, 362 m at 12 weeks vs. 315 m at base line), but it decreased in the 40 patients treated with conventional therapy alone (204 m at 12 weeks vs. 270 m at base line; P < 0.002 for the comparison of the treatment groups). Indexes of the quality of life were improved only in the epoprostenol group (P < 0.01). Hemodynamics improved at 12 weeks in the epoprostenol-treated patients. The changes in mean pulmonary-artery pressure for the epoprostenol and control groups were -8 percent and +3 percent, respectively (difference in mean change, -6.7 mm Hg; 95 percent confidence interval, -10.7 to -2.6 mm Hg; P < 0.002), and the mean changes in pulmonary vascular resistance for the epoprostenol and control groups were -21 percent and +9 percent, respectively (difference in mean change, -4.9 mm Hg/liter/min; 95 percent confidence interval, -7.6 to -2.3 mm Hg/liter/min; P < 0.001). Eight patients died during the study, all of whom had been randomly assigned to conventional therapy (P = 0.003). Serious complications included four episodes of catheter-related sepsis and one thrombotic event.

CONCLUSIONS

As compared with conventional therapy, the continuous intravenous infusion of epoprostenol produced symptomatic and hemodynamic improvement, as well as improved survival in patients with severe primary pulmonary hypertension.

Right ventricular function in patients with severe COPD evaluated for lung transplantation. Lung Transplant Group

Right ventricular function was measured in ten patients with severe COPD (mean FEV1 = 0.48 +/- 0.2 L/s) as part of an evaluation for single lung transplant (SLT). Right ventricular ejection fraction (RVEF) was determined by two methods: first-pass radionuclide scan by multigated acquisition (MUGA) and by using a fast thermistor tipped RVEF/volumetric pulmonary artery catheter. None of the patients had clinical evidence of active right heart failure, although mild resting pulmonary hypertension (mean pulmonary artery pressure [PAP] = 24 +/- 4 mm Hg) that worsened with minimal exercise (mean PAP = 39 +/- 11 mm Hg) was present. There was a significant difference in RVEF measured by the two methods (mean MUGA RVEF = 57 +/- 10%, mean catheter RVEF = 27 +/- 8%; p < 0.00005). RVEF determined by both methods was correlated with hemodynamic and gas exchange variables obtained during rest and at maximal exercise. There were significant, yet inverse, correlations between RVEF measured by catheter and cardiac index measured during exercise (CIex), as well as with exercise pulmonary vascular resistance index (PVRI). There were no significant correlations found between MUGA RVEF and any gas exchange or hemodynamic variables. Significant correlations were found with the catheter-measured right ventricular end-diastolic volume (RVEDV) and CIex (r = 0.9 p < 0.005), with maximal oxygen consumption during exercise (VO2max) (r = 0.86 p < 0.0025), with exercise stroke volume index (SVI) (r = 0.76 p < 0.01), and exercise central venous pressure (CVP) (r = 0.62 p < 0.05). Echocardiographic studies revealed right ventricular dilatation and mild tricuspid regurgitation (TR) in all patients. The strong correlation between RVEDV, CIex, and VO2max supports the concept that in these patients, as long as there is no clinical evidence of right heart failure (resting CVP still within normal limits), those with the largest RVEDVs use the Frank Starling principle to their best advantage to remain more functional.(ABSTRACT TRUNCATED AT 400 WORDS)