Lung transplantation for alpha 1-antitrypsin deficiency emphysema

Improving Screening for Alpha-1 Antitrypsin Deficiency with Direct Testing in the Pulmonary Function Testing Laboratory

Alpha-1 antitrypsin deficiency (AATD) is a common but highly underdiagnosed genetic disorder that may lead to chronic obstructive pulmonary disease (COPD), bronchiectasis, and liver disease. Early diagnosis is key to altering the course of disease as well as informing family members of potential risk. This randomized, prospective observational study compares the different testing modalities for AATD testing of at-risk patients initiated in the pulmonary function testing (PFT) laboratory. Providing a recommendation with a prescription for serologic testing, providing a finger-stick testing method (AlphaKit), and providing a buccal swab testing method (AlphaID) were compared to the community standard of referring the patient back to the PFT-ordering provider only. Results show that testing directly in the PFT laboratory has an odds ratio (OR) for completing testing of 35.14 (5.33 - 999.99), p-value of <0.0001, for buccal swab testing and an OR of 17.09 (2.58 - 729.99), p-value of 0.0002, for finger-stick testing compared to the community standard. Providing a prescription was no better than referral back to the PFT-ordering provider with an OR of 2.61(0.33 - 119.36), p-value of 0.6412. Resources needed to have testing performed by the Respiratory Therapy department were minimal with an average time of 1 to 5 minutes per patient tested. Causes of testing refusal were also identified. In conclusion, direct testing for AATD by respiratory therapists at the conclusion of PFT testing shows a significant improvement in rates of testing, especially with testing that utilizes buccal swab sample collection.

European Respiratory Society statement: diagnosis and treatment of pulmonary disease in α1-antitrypsin deficiency

α1-antitrypsin deficiency (AATD) is the most common hereditary disorder in adults. It is associated with an increased risk of developing pulmonary emphysema and liver disease. The pulmonary emphysema in AATD is strongly linked to smoking, but even a proportion of never-smokers develop progressive lung disease. A large proportion of individuals affected remain undiagnosed and therefore without access to appropriate care and treatment.

The most recent international statement on AATD was published by the American Thoracic Society and the European Respiratory Society in 2003. Since then there has been a continuous development of novel, more accurate and less expensive genetic diagnostic methods. Furthermore, new outcome parameters have been developed and validated for use in clinical trials and a new series of observational and randomised clinical trials have provided more evidence concerning the efficacy and safety of augmentation therapy, the only specific treatment available for the pulmonary disease associated with AATD.

As AATD is a rare disease, it is crucial to organise national and international registries and collect information prospectively about the natural history of the disease. Management of AATD patients must be supervised by national or regional expert centres and inequalities in access to therapies across Europe should be addressed.

Alpha-1 proteinase inhibitors for the treatment of alpha-1 antitrypsin deficiency: safety, tolerability, and patient outcomes

Alpha-1 antitrypsin (AAT) deficiency remains an underrecognized genetic disease with predominantly pulmonary and hepatic manifestations. AAT is derived primarily from hepatocytes; however, macrophages and neutrophils are secondary sources. As the natural physiological inhibitor of several proteases, most importantly neutrophil elastase (NE), it plays a key role in maintaining pulmonary protease–antiprotease balance. In deficient states, unrestrained NE activity promotes damage to the lung matrix, causing structural defects and impairing host defenses. The commonest form of AAT deficiency results in a mutated Z AAT that is abnormally folded, polymerized, and aggregated in the liver. Consequently, systemic levels are lower, resulting in diminished pulmonary concentrations. Hepatic disease occurs due to liver aggregation of the protein, while lung destruction ensues from unopposed protease-mediated damage. In this review, we will discuss AAT deficiency, its clinical manifestations, and augmentation therapy. We will address the safety and tolerability profiles of AAT replacement in the context of patient outcomes and cost-effectiveness and outline future directions for work in this field.

Survival benefit of lung transplantation for chronic obstructive pulmonary disease in Sweden

BACKGROUND

Lung transplantation (LTx) is a therapeutic option for patients with life-threatening chronic obstructive pulmonary disease (COPD) that is refractory to conventional therapies. The survival benefit of LTx for COPD is difficult to assess. The aim of this study was to evaluate the Swedish series of LTx performed to treat COPD and to identify differences in outcome between COPD related to severe alpha-1-antitrypsin deficiency (AATD) and COPD with normal alpha-1-antitrypsin (AAT) levels.

METHODS

We retrospectively reviewed the data of 342 patients (128 AATD and 214 non-AATD) receiving lung transplants for end stage COPD from 1990 through 2012.

RESULTS

The majority (71%) of patients received a single lung transplant. The median survival time after LTx for all COPD patients was 9 years (95% confidence interval [CI]: 8 to 10). Non-AATD recipients had a shorter survival time than AATD recipients, 6 years (95% CI: 5.0 to 8.8) versus 12 years (95% CI: 9.6 to 13.5, p = 0.000). Mortality was higher among non-AATD recipients after adjusting for age, pack-years of smoking, body mass index, oxygen therapy use, exercise capacity, donor age, cytomegalovirus mismatch, and transplant type (hazard ratio 1.70, 95% CI: 1.02 to 2.82). The 5-year and 10-year survival rates for the AATD recipients were 75% and 59%, respectively, compared with 60% and 31% for the non-AATD recipients. Early deaths were mainly due to cardio/cerebrovascular accidents and sepsis, and late deaths to bronchiolitis obliterans syndrome and pulmonary infections.

CONCLUSIONS

Survival after LTx is significantly better for patients with severe AATD and end stage COPD than for the patients with COPD related to cigarette smoking.

Augmentation therapy in alpha-1 antitrypsin deficiency: advances and controversies

Alpha-1 antitrypsin (AAT) deficiency is a hereditary condition characterized by low levels of AAT in plasma and hence diffusion into tissues. One of the most relevant characteristics of the disease is the development of panacinar emphysema due to an imbalance between proteases and antiproteases in the presence of environmental triggers. Left untreated, severe obstructive lung disease may develop. Avoidance of environmental triggers such as cigarette smoking constitutes a critical component of AAT deficiency treatment. Intravenous augmentation therapy is the only specific therapy for the condition that has been approved by the US Food and Drug Administration (FDA). While this therapy likely slows the rate of progression of emphysema and may improve survival in selected individuals with severe AAT deficiency, the gold standard for proof of efficacy is lacking. Areas where controversy exists regarding the use of AAT augmentation therapy include: (1) indications for treatment, (2) selection of specific AAT augmentation therapy, (3) appropriate dose and interval of administration, (4) cost effectiveness, (5) frequency and mode of follow up of treated patients, (6) use of augmentation therapy after lung transplantation, (7) use of recombinant AAT supplementation, (8) alternative delivery routes, and (9) genetic therapy. In this review we describe the advances in treatment and try to address some of the current controversies in AAT deficiency management.

Safety and efficacy of alpha-1-antitrypsin augmentation therapy in the treatment of patients with alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency (AATD), also known as alpha1-proteinase inhibitor deficiency, is an autosomal co-dominant condition. The genotypes associated with AATD include null, deficient, and dysfunctional alpha-1-antitrypsin (A1AT) variants, which result in low levels of circulating functional A1AT, unbalanced protease activity, and an increased risk of developing lung emphysema, the leading cause of morbidity in these patients. Furthermore, the most common abnormal genotype, Pi*ZZ may also cause trapping of abnormally folded protein polymers in hepatocytes causing liver dysfunction. A major focus of therapy for patients with lung disease due to AATD is to correct the A1AT deficiency state by augmenting serum levels with intravenous infusions of human plasma-derived A1AT. This strategy has been associated with effective elevations of A1AT levels and function in serum and lung epithelial fluid and observational studies suggest that it may lead to attenuation in lung function decline, particularly in patients with moderate impairment of lung function. In addition, an observational study suggests that augmentation therapy is associated with a reduction of mortality in subjects with AATD and moderate to severe lung impairment. More recent randomized placebo-controlled studies utilizing computer scan densitometry suggest that this therapy attenuates lung tissue loss. Augmentation therapy has a relative paucity of side effects, but it is highly expensive. Therefore, this therapy is recommended for patients with AATD who have a high-risk A1AT genotype with plasma A1AT below protective levels (11 μM) and evidence of obstructive lung disease. In this article, we review the published evidence of A1AT augmentation therapy efficacy, side effects, and safety profile.

Thirteen-year experience in lung transplantation for emphysema

BACKGROUND

Emphysema is the most common indication for lung transplantation. Recipients include younger patients with genetically determined alpha-1 antitrypsin deficiency (AAD) and, more commonly, patients with chronic obstructive pulmonary disease (COPD). We analyzed the results of our single-institution series of lung transplants for emphysema to identify outcome differences and factors predicting mortality and morbidity in these two groups.

METHODS

A retrospective analysis was undertaken of the 306 consecutive lung transplants for emphysema performed at our institution between 1988 and 2000 (220 COPD, 86 AAD). Follow-up was complete and averaged 3.7 years.

RESULTS

The mean age of AAD recipients (49 +/- 6 years) was less than those with COPD (55 +/- 6 years; p < 0.001). Hospital mortality was 6.2%, with no difference between COPD and AAD, or between single-lung transplants and bilateral-lung transplants. Hospital mortality during the most recent 6 years was significantly lower (3.9% vs 9.5%, p = 0.044). Five-year survival was 58.6% +/- 3.5%, with no difference between COPD (56.8% +/- 4.4%) and AAD (60.5% +/- 5.8%). Five-year survival was better with bilateral-lung transplants (66.7% +/- 4.0%) than with single-lung transplants (44.9% +/- 6.0%, p < 0.005). Independent predictors of mortality by Cox analysis were single lung transplantation (relative hazard = 1.98, p < 0.001), and need for cardiopulmonary bypass during the transplant (relative hazard = 1.84, p = 0.038).

CONCLUSIONS

AAD recipients, despite a younger age, do not achieve significantly superior survival results than those with COPD. Bilateral lung transplantation for emphysema results in better long-term survival. Accumulated experience and modifications in perioperative care over our 13-year series may explain recently improved early and long-term survival.

Alpha(1)-Antitrypsin Deficiency

Most of the care of liver disease in alpha(1)-antitrypsin (alpha(1)-AT) deficiency involves supportive management for complications of chronic liver disease including gastrointestinal bleeding, ascites, edema, encephalopathy, coagulation disturbances, spontaneous bacterial peritonitis, and hepatorenal syndrome. Some of these patients will have manifestations of cholestatic injury, including pruritus, hypercholesterolemia, and steatorrhea with fat-soluble vitamin deficiencies. The major challenge for the clinician taking care of these patients is the timing of referral for liver transplantation therapy. Timing of such referral is a relatively straightforward decision in alpha(1)-AT-deficient patients with progressive liver dysfunction. Some patients have nonprogressive or slowly progressing liver disease even after the development of cirrhosis or portal hypertension. Timing of liver transplantation in these patients should not be based simply on the presence of cirrhosis, portal hypertension or mild liver synthetic dysfunction, but rather on the basis of a subjective judgment by the hepatologist, patient, and family that manifestations of liver disease are interfering with overall life functioning.

Liver injury in alpha 1-antitrypsin deficiency

Alpha 1-antitrypsin deficiency is the most common genetic cause of liver disease in children. It is also associated with chronic liver disease, hepatocellular carcinoma, and pulmonary emphysema in adults. Liver injury is caused by hepatotoxic effects of retention of the mutant alpha 1-antitrypsin molecule within the endoplasmic reticulum of liver cells, and emphysema is caused by uninhibited proteolytic damage to elastic tissue in the lung parenchyma. Recent studies of the biochemistry and cell biology of the mutant alpha 1-antitrypsin molecule have led to advances in understanding susceptibility to liver injury and in developing new strategies for prevention of both liver and lung disease.