Hemodynamic Mechanisms of Exercise-Induced Pulmonary Hypertension in Patients with Lymphangioleiomyomatosis: The Role of Exercise Stress Echocardiography

Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is an ultra-rare, slowly progressive neoplastic cystic disease, belonging to the group of PEComas. It can occur sporadically or associated to tuberous sclerosis complex disease and affects mainly women in child-birth age. Dyspnoea is the most frequent symptom referred to the time of diagnosis, however spontaneous pneumothorax may be a typical presentation associated to extrathoracic manifestations, such as renal angiomyolipomas. In the last decade, important advances in understanding molecular mechanisms underlying the LAM pathogenesis have been reached. It has allowed to obtain improvements in the research of novel biomarkers, treatment and a better management of the disease.

Computer grading of lung disease severity in patients with lymphangioleiomyomatosis referred for transplantation

Objectives

Lymphangioleiomyomatosis (LAM) patients with severe lung disease may be considered for lung transplantation. Clinical, physiologic, and quality of life data are usually employed for referral. The aim of this study was to determine whether computed tomographic measurement of lung volume occupied by cysts (cyst score) complemented clinical and physiologic data in supporting referral for transplantation.

Methods

Forty-one patients were studied. Pre-referral clinical data, pulmonary function tests, exercise testing, and high-resolution computed tomography (HRCT) scans were obtained. From HRCT, a computer-aided diagnostic program was employed to calculate cyst scores. These data were compared to those of 41 age-matched LAM patients not referred for lung transplantation.

Results

Cyst score, and % predicted FEV1 and DLCO were respectively, 48.1 ± 9.4%, 36.5 ± 9.1%, and 35.0 ± 10.7%. For the control group, cyst score, FEV1, and DLCO were respectively, 14.8 ± 8.3%, 77.2 ± 20.3%, and 66.7 ± 19.3%. Cyst score values showed a normal distribution. However, the frequency distribution of FEV1 was skewed to the right while the distribution of DLCO was bimodal. Correlations between cyst score and FEV1 and DLCO for the study group were respectively, r = − 0.319 and r = − 0.421.

Conclusions

LAM patients referred for lung transplantation had nearly 50% of lungs occupied by cysts. Correlations between cyst score and FEV1 or DLCO were weak; as shown previously, DLCO was better related to cyst number while FEV1 had a better association with cyst size. Given its normal distribution, cyst score measurements may assist in evaluation of pre-transplant severity of lung disease before referral for transplantation.

Improving Survival in Lymphangioleio-myomatosis: A 16-Year Observational Study in a Large Cohort of Patients

BACKGROUND

Over the last 2 decades, great progress has been made in the understanding of the clinical aspects and pathogenesis of lymphangioleiomyomatosis (LAM), leading to publication of guidelines and approval of an effective therapy.

OBJECTIVES

Aim of our study was to describe how the management and the natural history of this rare disease have changed after the publication of the ERS and American Thoracic Society/Japanese Respiratory Society guidelines and the introduction of sirolimus.

METHODS

We examined 162 LAM patients followed at our center between 2001 and 2017, reporting clinical characteristics and diagnostic approach. Response to sirolimus in patients undergoing long-term treatment and mortality risk, estimated in terms of cumulative incidence taking into account organ transplantation as a competing cause of the event, were evaluated. The difference in the cumulative incidence between the patients admitted to the observation before 2011 and after 2011, year of the publication of the MILES trial for the efficacy of sirolimus, has also been estimated.

RESULTS

Sixty-one patients had a histological diagnosis (22 from 2010 onward). 101 patients received a radiological diagnosis according to the guidelines criteria. Pulmonary function tests remained stable over a 3-year treatment period in patients who received sirolimus for over 12 months. The cumulative incidence of mortality after 10 years in the whole population was 25.5%. The cumulative incidence of mortality after 5 years was significantly lower in patients who entered the study since 2011 (after publication of the MILES trial) than in patients who entered the study before.

CONCLUSIONS

We provide the data supporting the long-term efficacy of sirolimus therapy in a large cohort of patients with functional impairment and other manifestations of the disease. Our results also suggest that the advent of sirolimus and the publication of international guidelines changed the natural history of the disease lowering the mortality and reducing the need of invasive diagnostic techniques.

Risk factors for right ventricular dysfunction in patients with lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare disease characterized by diffuse cystic lesions of the lung. The present study was designed to evaluate the right ventricular (RV) function in LAM patients via single-beat real-time three-dimensional echocardiography (RT-3DE) and to investigate the factors affecting RV function in LAM patients. According to tricuspid regurgitation velocity (TRV), forty-five female LAM patients [(44.07 ± 10.22) years old] were divided into TRV ≤ 2.8 m/s group (n = 29) and TRV > 2.8 m/s group (n = 16). Relative echocardiography parameters were assessed by conventional transthoracic echocardiography, Doppler tissue imaging (DTI) and RT-3DE, respectively. Pulmonary function tests and the six-minute walk tests (SMWT) were also performed for LAM patients. We found that most of RV functional parameters in LAM patients were worse than that in control patients, although left ventricular dysfunction was not significantly observed. Correlation analysis showed that 3D echocardiographic RV ejection fraction (RVEF) was negatively correlated with pulmonary vascular resistance (PVR), TRV, and the decrease of oxygen saturation (SpO₂) post SMWT, and positively correlated with Forced expiratory volume in the first second/forced vital capacity, carbon monoxide diffusion predicted value, SMWT distance, and resting SpO₂ in LAM patients. Multivariate stepwise linear regression analysis showed that PVR and SpO2 before SMWT were independent influence factors of RVEF in LAM patients. In this study, we found that RV dysfunction was presented in LAM patients, although left ventricular dysfunction was not significantly obvious. The main influence factors of RVEF were PVR and hypoxia. RT-3DE is a low-cost and noninvasive way to evaluate RV function in LAM patients.

Pulmonary hypertension and chronic lung disease: where are we headed?

Pulmonary hypertension related to chronic lung disease, mainly represented by COPD and idiopathic pulmonary fibrosis, is associated with a worse outcome when compared with patients only affected by parenchymal lung disease. At present, no therapies are available to reverse or slow down the pathological process of this condition and most of the clinical trials conducted to date have had no clinically significant impact. Nevertheless, the importance of chronic lung diseases is always more widely recognised and, along with its increasing incidence, associated pulmonary hypertension is also expected to be growing in frequency and as a health burden worldwide. Therefore, it is desirable to develop useful and reliable tools to obtain an early diagnosis and to monitor and follow-up this condition, while new insights in the therapeutic approach are explored.