The beneficial effects of nocturnal oxygen therapy (NOT) in chronic obstructive pulmonary disease (COPD) patients with mild-to-moderate daytime hypoxaemia (arterial oxygen tension (Pa,O 2 ) in the range 7.4±9.2 kPa (56±69 mmHg)) and exhibiting sleep-related oxygen desaturation remains controversial. The effectiveness of NOT in that category of COPD patients was studied. The end points included pulmonary haemodynamic effects after 2 yrs of follow-up, survival and requirement for long-term oxygen therapy (LTOT).Seventy-six patients could be randomized, 41 were allocated to NOT and 35 to no NOT (control). The goal of NOT was to achieve an arterial oxygen saturation of >90% throughout the night. All these patients underwent polysomnography to exclude an associated obstructive sleep apnoea syndrome. The two groups exhibited an identical meanSD daytime Pa,O 2 of 8.40.4 kPa (633 mmHg) at baseline.Twenty-two patients (12 in the NOT group and 10 in the control group, p=0.98) required LTOT during the whole follow-up (3514 months). Sixteen patients died, nine in the NOT group and seven in the control group (p=0.84). Forty-six patients were able to undergo pulmonary haemodynamic re-evaluation after 2 yrs, 24 in the NOT and 22 in the control group. In the control group, mean resting pulmonary artery pressure increased from 19.85.6 to 20.56.5 mmHg, which was not different from the change in mean pulmonary artery pressure in the NOT group, from 18.34.7 to 19.55.3 mmHg (p= 0.79).Nocturnal oxygen therapy did not modify the evolution of pulmonary haemodynamics and did not allow delay in the prescription of long-term oxygen therapy. No effect of NOT on survival was observed, but the small number of deaths precluded any firm conclusion. These results suggest that the prescription of nocturnal oxygen therapy in isolation is probably not justified in chronic obstructive pulmonary disease patients. Eur Respir J 1999; 14: 1002±1008. The beneficial effects of long-term oxygen therapy (LTOT) have been demonstrated in chronic obstructive pulmonary disease (COPD) patients with marked daytime hypoxaemia, i.e. in patients with an arterial oxygen tension (Pa,O 2 ) measured in the stable state of the disease, of <7.3 kPa (<55 mmHg) or in the range 7.4±7.8 kPa (56±59 mmHg), and exhibiting "cor pulmonale" or polycythaemia [1, 2]. These beneficial effects include improved survival [1, 2], but also an amelioration of pulmonary haemodynamics [3,4]. The beneficial effects of LTOT on survival have not been observed in COPD patients with moderate hypoxaemia (Pa,O 2 in the range 7.4±8.6 kPa (56±65 mmHg)), as indicated by a very recent Polish study [5].The worsening of hypoxaemia during sleep, and particularly during rapid eye movement sleep, has been well established in patients with advanced COPD [6±10]. It must be underlined, however, that most of these studies have included patients with severe COPD, exhibiting marked daytime hypoxaemia. Conventional LTOT, given for >15±18 h . day -1 , compulsorily includes sleep time and, accordingly, sle...
It has been hypothesized but not firmly established that sleep-related hypoxaemia could favour the development of pulmonary hypertension in chronic obstructive pulmonary disease (COPD) patients without marked daytime hypoxaemia.We have investigated the relationships between pulmonary function data, sleeprelated desaturation and daytime pulmonary haemodynamics in a group of 94 COPD patients not qualifying for conventional O 2 therapy (daytime arterial oxygen tension (Pa,O 2 ) in the range 7.4-9.2 kPa (56-69 mmHg)). Nocturnal desaturation was defined by spending ≥30% of the recording time with a transcutaneous O 2 saturation <90%. An obstructive sleep apnoea syndrome was excluded by polysomnography.Sixty six patients were desaturators (Group 1) and 28 were nondesaturators (Group 2). There was no significant difference between Groups 1 and 2 with regard to pulmonary volumes and Pa,O 2 (8.4±0.6 vs 8.4±0.4 kPa (63±4 vs 63±3 mmHg)) but arterial carbon dioxide tension (Pa,CO 2 ) was higher in Group 1 (6.0±0.7 vs 5.3±0.5 kPa (45±5 vs 40±4 mmHg); p<0.0001). Mean pulmonary artery pressure (Ppa) was very similar in the two groups (2.6±0.7 vs 2.5±0.6 kPa (19±5 vs 19±4 mmHg)). No individual variable or combination of variables could predict the presence of pulmonary hypertension.It is concluded that in these patients with chronic obstructive pulmonary disease with modest daytime hypoxaemia, functional and gasometric variables (with the noticeable exception of arterial carbon dioxide tension) cannot predict the presence of nocturnal desaturation; and that mean pulmonary artery pressure is not correlated with the degree and duration of nocturnal hypoxaemia. These results do not support the hypothesis that sleep-related hypoxaemia favours the development of pulmonary hypertension. Eur Respir J 1997; 10: 1730-1735 The worsening of hypoxaemia during sleep in patients with chronic obstructive pulmonary disease (COPD) has been documented since the early 1960s [1], and has since been confirmed by polysomnographic studies [2,3], which have included continuous monitoring of oxygen saturation from the late 1970s [4][5][6][7][8][9][10]. It must be emphasized that most of these studies have included patients with severe COPD exhibiting marked daytime hypoxaemia. Is sleep-related hypoxaemia present in patients with less severe COPD with mild or absent daytime hypoxaemia? Several studies of the literature [11][12][13] have shown that a relatively high percentage of these COPD patients exhibit significant nocturnal hypoxaemia, which naturally raises the question: Does this hypoxaemia, limited to sleep, deserve treatment with nocturnal oxygen? Such a treatment could be justified if nocturnal hypoxaemia had deleterious effects on life expectancy, which is rather controversial [14,15], and on pulmonary haemodynamics. It has been hypothesized [16,17] that isolated nocturnal hypoxaemia, occurring in patients without significant daytime hypoxaemia, could lead to permanent (daytime) pulmonary hypertension, but this hypothesis has not, so...
The diagnosis of von Willebrand disease (VWD) remains difficult in a significant proportion of patients. A Spanish multicentre study investigated a cohort of 556 patients from 330 families who were analysed centrally. VWD was confirmed in 480. Next generation sequencing (NGS) of the whole coding VWF was carried out in all recruited patients, compared with the phenotype, and a final diagnosis established. A total of 238 different VWF mutations were found, 154 were not included in the Leiden Open Variation Database (LOVD). Of the patients, 463 were found to have VWF mutation/s. A good phenotypic/genotypic association was estimated in 96.5% of the patients. One hundred seventy-four patients had two or more mutations. Occasionally a predominant phenotype masked the presence of a second abnormality. One hundred sixteen patients presented with mutations that had previously been associated with increased von Willebrand factor (VWF) clearance. RIPA unavailability, central phenotypic results disagreement and difficult distinction between severe type 1 and type 3 VWD prevented a clear diagnosis in 70 patients. The NGS study facilitated an appropriate classification in 63 of them. The remaining seven patients presented with a VWF novel mutation pending further investigation. In five patients with a type 3 and two with a type 2A or 2B phenotype with no mutation, an acquired von Willebrand syndrome (AVWS) was suspected/confirmed. These data seem to support NGS as a first line efficient and faster paradigm in VWD diagnosis.
Molecular diagnosis of patients with von Willebrand disease is pending in most populations due to the complexity and high cost of conventional molecular analyses. The need for molecular and clinical characterization of von Willebrand disease in Spain prompted the creation of a multicenter project (PCM-EVW-ES) that resulted in the largest prospective cohort study of patients with all types of von Willebrand disease. Molecular analysis of relevant regions of the VWF, including intronic and promoter regions, was achieved in the 556 individuals recruited via the development of a simple, innovative, relatively low-cost protocol based on microfluidic technology and next-generation sequencing. A total of 704 variants (237 different) were identified along VWF, 155 of which had not been previously recorded in the international mutation database. The potential pathogenic effect of these variants was assessed by in silico analysis. Furthermore, four short tandem repeats were analyzed in order to evaluate the ancestral origin of recurrent mutations. The outcome of genetic analysis allowed for the reclassification of 110 patients, identification of 37 asymptomatic carriers (important for genetic counseling) and re-inclusion of 43 patients previously excluded by phenotyping results. In total, 480 patients were definitively diagnosed. Candidate mutations were identified in all patients except 13 type 1 von Willebrand disease, yielding a high genotype-phenotype correlation. Our data reinforce the capital importance and usefulness of genetics in von Willebrand disease diagnostics. The progressive implementation of molecular study as the first-line test for routine diagnosis of this condition will lead to increasingly more personalized and effective care for this patient population.
The aim of the present study was to compare the evolution of pulmonary haemodynamics and of arterial blood gases in chronic obstructive pulmonary disease (COPD) patients with mild-to-moderate hypoxaemia, with or without sleep-related oxygen desaturation.COPD patients with daytime arterial oxygen partial pressure in the range 56-69 mmHg were included prospectively. Sleep-related oxygen desaturation was defined as spending ¢30% of the nocturnal recording time with arterial oxygen saturation v90%.From the 64 patients included, 35 were desaturators (group 1) and 29 were nondesaturators (group 2). At baseline (t0), patients with sleep-related desaturation had a significantly higher daytime (mean¡SD) arterial carbon dioxide partial pressure (Pa,CO 2 ) (44.9¡4.9 mmHg versus 41.0¡4.1 mmHg, p~0.001) whereas mean pulmonary artery pressure (mPAP) was similar in the two groups. After 2 yrs (t2) of followup, 22 desaturators and 14 nondesaturators could be re-evaluated, including pulmonary haemodynamic measurements. None of the nondesaturator patients became desaturators at t2. The difference between the two groups in terms of daytime Pa,CO 2 was still present at t2. The mean changes in mPAP from t0 to t2 were similar between the two groups, as were the rates of death or requirement for long-term oxygen therapy (American Thoracic Society criteria) during follow-up of up to 6 yrs.The presence of sleep-related oxygen desaturation is not a transitional state before the worsening of daytime arterial blood gases, but is a characteristic of some chronic obstructive pulmonary disease patients who have a higher daytime arterial carbon dioxide partial pressure. Such isolated nocturnal hypoxaemia or sleep-related worsening of moderate daytime hypoxaemia does not appear to favour the development of pulmonary hypertension, nor to lead to worsening of daytime blood gases. Eur Respir J 2001; 17: 848-855.
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