[Pulmonary hypertension associated with disorders of the respiratory system]

Pulmonary hypertension associated with disorders of the respiratory system is defined by a pulmonary artery mean pressure above 20 mmHg at rest in stable disease. The most frequent form of precapillary pulmonary hypertension is associated with chronic obstructive pulmonary disease, because of its high prevalence. Pulmonary vascular remodeling occurs in the small pulmonary arteries and is due mainly to chronic alveolar hypoxia. Pulmonary hypertension associated with disorders of the respiratory system is usually mild to moderate, with resting pulmonary artery mean pressure ranging between 20 and 35 mm Hg. It may increase markedly during sleep, exercise or exacerbation of respiratory failure, however. Abrupt postload elevation can lead to right heart failure, an indisputable indicator of prognosis. Because the symptoms of pulmonary hypertension are minimal relative to those of the chronic hypoxic lung disease, noninvasive diagnosis is difficult, particularly in patients with chronic obstructive pulmonary disease. Oxygen therapy (at least 16 h/day) is currently the best treatment for this type of pulmonary arterial hypertension.

[Physiological functional tests to evaluate pulmonary arterial hypertension]

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare and complex disease, which requires careful diagnostic evaluation.

STATE OF THE ART

Most patients have a mild decrease in lung volumes and a moderate decrease in carbon monoxide transfer factor. Mild to moderate arterial hypoxaemia, is often present, associated with a mild respiratory alkalosis. When hypoxaemia is severe, it may represent an intracardiac shunt. Right heart catheterisation is required to confirm the diagnosis and in most cases shows a significant elevation of pulmonary artery pressure due to an increase in pulmonary vascular resistance. The haemodynamic profile and the response to an acute pulmonary vasodilator challenge are determinants of prognosis. Finally, exercise capacity which is usually assessed by the six minute walk test provides an overall functional measure of disease severity, response to therapy, and progression.

PERSPECTIVES

Functional evaluation of the heart using echocardiography will play an increasing role in the evaluation of PAH.

CONCLUSIONS

Physiological measurements in PAH have several objectives. They form part of the diagnostic definition, allow the exclusion of other conditions and are tools for the assessment of severity, prognosis and response to therapy.

[Role of gastroesophageal reflux in asthma in infants and young children]

Gastroesophageal reflux (GER) occurs more frequently in asthmatic children than in general population. Esophageal pH recording data may be somewhat particular. The debate on GER increasing bronchial obstruction or GER being a parallel phenomenon remains controversial. Hypotheses are: acid microaspirations giving bronchospasm, vagally-transmitted reflex, or more probably coexisting phenomena. Pulmonary contamination is rarely seen during esophageal scintigraphy. Asthma symptoms are rarely clearly correlated to acid reflux episodes in pH-recording studies. However the esophageal acid infusion test may increase bronchial obstruction in adult asthmatics. Basically, when should one seek GER in asthmatic children? Many authors keep this for asthmatic children not responding to conventional treatment, also keeping in mind that GER-specific therapy efficacy is often difficult to appreciate in such patients. Briefly, one may speculate that GER improves with bronchodilator treatment in most cases.

"Natural history" of pulmonary hypertension in a series of 131 patients with chronic obstructive lung disease

The prognostic value and the evolution of pulmonary hypertension (PH) in patients with markedly hypoxemic chronic obstructive pulmonary disease (COPD), treated or not with long-term oxygen therapy (LTOT), has been extensively investigated. However, little is known in patients with mildly or moderately hypoxemic COPD not requiring LTOT. Therefore, we assessed the evolution of pulmonary hemodynamics in 131 patients with stable COPD by performing two right heart catheterizations at a mean (+/- SD) time interval of 6.8 +/- 2.9 yr. At inclusion (T0), no patient had PH (i.e., the mean pulmonary artery pressure [Ppa] at rest was < 20 mm Hg). Group 1 included 55 patients without exercising PH and group 2 included 76 patients with exercising PH, defined by a pulmonary arterial pressure (Ppa) > 30 mm Hg during a steady-state 40-W exercise. Group 2 patients compared with group 1 patients had a significantly higher resting Ppa (16 +/- 3 mm Hg versus 14 +/- 2 mm Hg, p = 0.001). At the second catheterization, 33 (25%) patients (9 of 55 in group 1, 24 of 76 in group 2, p = 0.048) showed a resting Ppa > 20 mm Hg, but PH was generally mild, ranging from 20 to 42.5 mm Hg. The mean Ppa at second evaluation was 16 +/- 5 mm Hg in group 1 and 19 +/- 7 mm Hg in group 2 (p = 0.01). The patients who developed resting PH at the second catheterization (T1) had higher resting and exercising Ppa (p = 0.001 and p = 0.002, respectively), and significantly lower resting and exercising Pa(O(2)) (p = 0.005 and p = 0.012, respectively) at T0. Logistic regression analysis showed that resting and exercising Ppa were independent predictors (at T0) for the subsequent development of PH (p = 0.029 and p = 0.027, respectively). The patients who developed resting PH (T1) had a significantly worsening of Pa(O(2)) (from 63.5 mm Hg at T0 to 60 mm Hg at T1, p = 0.047), whereas the Pa(O(2)) as a mean was stable in the remainder (69.5 mm Hg at T0 and T1). These results show the following. The progression of Ppa over time in patients with COPD with mild to moderate hypoxemia is rather slow, the average change for the group as a whole being of + 0.4 mm Hg/yr. Only about 25% of patients with COPD with mild to moderate hypoxemia and without resting PH at the onset will develop PH during a 6-yr follow-up. The patients with exercising PH at the onset have a significantly increased risk of developing PH over time. Only resting and exercising Ppa at the onset are independently related to the subsequent development of PH. However, in individual cases, the models of linear or logistic regression do not allow a pertinent prediction of the level of Ppa or the presence of PH at the second right heart catheterization.

Regulation of endothelin-1 at rest and during a short steady-state exercise in 21 COPD patients

Endothelin-1 (ET-1) is a vasoconstrictive peptide which may play a relevant role in the pathogenesis of pulmonary hypertension (PH) in COPD patients. We assessed the correlations of plasmatic ET-1 levels with pulmonary function data, arterial blood gases and pulmonary haemodynamics in 21 COPD patients with moderate to severe airway obstruction (FEV1: 1.19+/-0.49 l, mean+/-SD). There were 11 hypoxemic patients (PaO2 <65 mmHg). Six patients had resting PH (mean pulmonary artery pressure >/=20 mmHg). Eight patients had exercising PH (PAP >/=30 mmHg) during a short (6 min) 30 W steady state exercise. At rest, arterial ET-1 levels were significantly higher in COPD patients with hypoxemia when compared to those without hypoxemia (16.6+/-2.7 vs. 12.5+/-3.9 pM/l, P=0.02) and in COPD patients with PH when compared to those without PH (16.5+/-3.4 vs. 13+/-3.9 pM/l, P=0.04). Resting arterial ET-1 levels were negatively correlated with PaO2 (r=-0.45, P=0.05). At rest, the differences between mixed venous and arterial ET-1 levels were positively correlated with FEV1 (r=0.54, P=0.024). At exercise, the mean arterial ET-1 level was not significantly different from the mean resting ET-1 level (13.8+/-3.4 vs. 13.3+/-4 p M/l, NS). There were eight COPD patients who had decreasing arterial ET-1 levels between rest and the end of a 6 min exercise, and six COPD patients who had increasing arterial ET-1 levels. These variations of arterial systemic ET-1 levels from rest to exercise were negatively correlated with FEV1 (r=-0.66, P=0.01). We conclude that in COPD patients (1) at rest, arterial ET-1 levels are increased in hypoxemia or pulmonary hypertension and (2) at rest or during exercise, the turn-over of ET-1 may be dependent of the degree of the bronchial obstruction.

A phase II trial of radiochemotherapy with daily carboplatin, after induction chemotherapy (carboplatin and etoposide), in locally advanced nonsmall-cell lung cancer: final analysis

PURPOSE

To evaluate feasibility and efficacy of concomitant radiochemotherapy (CRCT) in Stage IIIB nonsmall-cell lung cancer (NSCLC), two induction chemotherapy cycles combining etoposide and carboplatin were first delivered, followed by CRCT with daily radiation fraction in association with carboplatin.

METHODS AND MATERIALS

Forty patients with biopsy-proven, locally advanced unresectable nonmetastatic NSCLC were enrolled. Induction chemotherapy consisted of two cycles (day 1 and day 28) of etoposide (VP16:100 mg/m2, days 1 to 3) and carboplatin (CBDCA:350 mg/m2, day 1). Irradiation starting at day 56, delivered 66 Gy in 2 Gy daily fraction, 5 days a week, along with a daily dose of CBDCA (15 mg/m2) given intravenously 2 to 4 h before radiation. In nonprogressive patients under induction chemotherapy, two additional cycles of VP16-CBDCA were administered 4 weeks after the completion of CRCT.

RESULTS

Out of the 40 patients enrolled (38 males, 2 females), 37 (93%) received induction chemotherapy as scheduled, with 38% Grade 3-4 hematological toxicity. Response rate to induction chemotherapy was 11% (4/37). No tumor became resectable. CRCT was delivered to 32 of these 37 patients, with full doses given to 91% of them. Clinical and hematological Grade 3-4 toxicity rates were 21 and 13%, respectively. Additional chemotherapy was delivered in 12 of 26 nonprogressive patients. At final evaluation, performed 3 months after the end of CRCT, 38% of 26 evaluable patients were responders (4 complete and 6 partial), leading to a 25% (10 of 40) overall objective response rate. Of these 10 responders, 8 became responders after CRCT only. Overall, the 1-year local control rate was 28% (11 of 40). The median survival time was 9 months and the 1-year and 2-year overall survival rates were 38 and 15%, respectively. Thirty-six patients died from local progression (25 patients), distant metastasis (9 patients), or pulmonary fibrosis (2 patients).

CONCLUSION

Concomitant CRCT with CBDCA is feasible with acceptable induction chemotherapy-related toxicity and a 1-year local control rate of 28%. Response rate to induction chemotherapy was low and better chemotherapy combination should be used to reduce distant failure probability and to improve local response rate before CRCT.

Gastroesophageal reflux in patients with asthma and chronic bronchitis

To determine the relationship between gastroesophageal (GE) reflux and pulmonary disease, we studied 21 asthmatics, 30 chronic bronchitics, 6 patients with GE reflux and no pulmonary symptoms, and 10 control subjects; GE reflux was diagnosed by pH monitoring and GE scintiscanning. Frequency of GE reflux in the asthmatics was 57%; in the chronic bronchitics it was 56%. Pulmonary function tests did not show any differences between patients with or without reflux. The GE reflux episodes were more numerous but shorter in asthmatics than in chronic bronchitics. Patients with digestive symptoms alone were no different from chronic bronchitics with respect to reflux. The mechanism whereby reflux triggers pulmonary problems was investigated using the following 2 tests: scintiscan for pulmonary aspiration, and esophageal acid infusion (0.1N HCl). Six pulmonary aspirations were detected. Only asthmatics, with or without reflux, showed any significant variations in maximal expiratory flow at 50% and 25% of VC after HCl infusion. Thus, our results show that asthmatics differ from chronic bronchitics by the characteristics of their reflux.