Bosentan in pulmonary arterial hypertension: a comparison between congenital heart disease and chronic pulmonary embolism

Background. In patients with pulmonary hypertension, it is unknown whether the treatment effect of bosentan is dependent on the duration of pulmonary vessel changes. Therefore, we studied the response to bosentan in patients with life-long pulmonary vessel changes (pulmonary arterial hypertension (PAH) due to congenital heart disease (CHD)) and in patients with subacutely induced pulmonary vessel changes (chronic thromboembolic pulmonary hypertension (CTEPH)).Methods. In this open-label study, 18 patients with PAH due to CHD and 16 patients with CTEPH were treated with bosentan for at least one year. All patients were evaluated at baseline and during follow-up by means of the six-minute walk distance (6-MWD) and laboratory tests.Results. Improvement of 6-MWD was comparable in patients with PAH due to CHD (444+/-112 m to 471+/-100 m, p=0.02), and in CTEPH (376+/-152 m to 423+/-141 m, p=0.03) after three months of treatment. After this improvement, 6-MWD stabilised in both groups.Conclusion. Although duration of pulmonary vessel changes is strikingly different in patients with PAH due to CHD and CTEPH, the effect of one year of bosentan treatment was comparable. The main treatment effect appears to be disease stabilisation and decreasing the rate of deterioration. (Neth Heart J 2009;17:334-8.).

Time course of restoration of systolic and diastolic right ventricular function after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension

BACKGROUND

In chronic thromboembolic pulmonary hypertension, right ventricular (RV) pressure overload causes RV remodeling and dysfunction. Successful pulmonary endarterectomy (PEA) initiates restoration of RV remodeling and global function. Little is known on the restoration of systolic and diastolic RV function. Using transthoracic echocardiography, we studied the time course and extent of postoperative restoration of systolic and diastolic RV function.

METHODS

In chronic thromboembolic pulmonary hypertension (n = 55, 36 women, age 52 ± 14 years), transthoracic echocardiography was performed before PEA (pre-PEA) and 2 weeks, 3 months, and 1 year postoperatively.

RESULTS

Two weeks postoperatively, RV afterload and dimension had decreased significantly, without further improvement during follow-up. Global RV function, expressed by the myocardial performance index, showed a gradual improvement (from pre-PEA 0.58 ± 0.29 to 0.45 ± 0.38, 0.39 ± 0.19, and 0.37 ± 0.18). In contrast, 2 weeks after PEA systolic RV function, as assessed by tricuspid annular plane systolic velocity excursion and peak tricuspid annular systolic velocity of the RV, had worsened, with a subsequent incomplete restoration during follow-up: tricuspid annular plane systolic velocity excursion from 19.3 ± 5.0 to 12.4 ± 2.5, 15.3 ± 3.0, and 16.8 ± 2.9 mm and systolic velocity of the right ventricle from 11.4 ± 3.0 to 9.6 ± 2.0, 10.0 ± 1.8, and 10.3 ± 1.7 cm/s. Postoperative diastolic RV function also showed a biphasic response: tricuspid inflow-to-annulus ratio from 6.1 ± 3.0 to 9.5 ± 3.5, 6.8 ± 2.4, and 6.3 ± 2.2 cm/s. Dynamics and ultimate level of restoration of systolic and diastolic RV function were similar in patients with and without residual pulmonary hypertension.

CONCLUSIONS

Postoperative reduction in RV afterload caused an immediate improvement in RV dimension and global function. In contrast, systolic and diastolic RV function deteriorated after PEA with subsequently a gradual yet incomplete restoration during 1-year follow-up.

WITHDRAWN: Predictors of long-term survival in pulmonary hypertension treated with bosentan

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at (http://www.elsevier.com/locate/withdrawalpolicy.

Protease-activated receptor-2 induces myofibroblast differentiation and tissue factor up-regulation during bleomycin-induced lung injury: potential role in pulmonary fibrosis

Idiopathic pulmonary fibrosis constitutes the most devastating form of fibrotic lung disorders and remains refractory to current therapies. The coagulation cascade is frequently activated during pulmonary fibrosis, but this observation has so far resisted a mechanistic explanation. Recent data suggest that protease-activated receptor (PAR)-2, a receptor activated by (among others) coagulation factor (F)Xa, plays a key role in fibrotic disease; consequently, we assessed the role of PAR-2 in the development of pulmonary fibrosis in this study. We show that PAR-2 is up-regulated in the lungs of patients with idiopathic pulmonary fibrosis and that bronchoalveolar lavage fluid from these patients displays increased procoagulant activity that triggers fibroblast survival. Using a bleomycin model of pulmonary fibrosis, we show that bleomycin induces PAR-2 expression, as well as both myofibroblast differentiation and collagen synthesis. In PAR-2-/- mice, both the extent and severity of fibrotic lesions are reduced, whereas myofibroblast differentiation is diminished and collagen expression is decreased. Moreover, fibrin deposition in the lungs of fibrotic PAR-2-/- mice is reduced compared with wild-type mice due to differential tissue factor expression in response to bleomycin. Taken together, these results suggest an important role for PAR-2 in the development of pulmonary fibrosis, and the inhibition of the PAR-2-coagulation axis may provide a novel therapeutic approach to treat this devastating disease.

[Chronic thrombo-embolic pulmonary hypertension]

Chronic thrombo-embolic pulmonary hypertension (CTEPH) was diagnosed in two patients, a man aged 55 years and a woman aged 54 years, who had both suffered an episode of pulmonary embolism. CTEPH is a rare but serious late complication of pulmonary embolism. If left untreated, it is a progressive disease with a poor prognosis. Pulmonary endarterectomy is the treatment of choice for CTEPH; both patients were treated successfully with this operation. In clinical practice patients are often initially misdiagnosed, due to unawareness of the condition, and are therefore subjected to a long delay before treatment. In the first patient the condition had not been recognised on CT scans. The second patient had initially been treated with psychotherapy for a suspected burn-out. All physicians involved in taking care of patients with pulmonary embolism, must be aware of this serious complication. Diagnosis and treatment of CTEPH require a high level of expertise.

Compartmental apoptosis and neutrophil accumulation in severe peritonitis

BACKGROUND

Migration and activation of polymorphonuclear neutrophils (PMN) and apoptosis are central to inflammatory tissue damage. This study examines the relation of these processes, and their expression in the abdominal, systemic, and bronchoalveolar compartments in patients with severe peritonitis.

MATERIALS AND METHODS

Thirty-one consecutive patients undergoing laparotomy for severe secondary peritonitis. Eight operated patients without peritonitis and 10 long-term mechanically ventilated noninfected patients served as controls. Peritoneal fluid, blood, and bronchoalveolar lavage fluid (BALF) was obtained on d 0 (day of initial laparotomy), 2, and 3. Levels of chemokines (interleukin (IL)-8 and monocyte chemotactic protein (MCP)-1), PMN-counts, PMN activation [myeloperoxidase (MPO), elastase] and apoptosis (nucleosomes) were determined.

RESULTS

In peritonitis patients, levels of chemokines and markers of PMN sequestration were increased in all compartments. IL-8 levels were higher in BALF than in plasma, and did not originate from the circulation or from lysis of alveolar cells. Pulmonary nucleosome levels were higher in patients who died (P=0.020), and corresponded with PMN-count in BALF (P<0.001), levels of chemokines (IL-8, P=0.003; MCP-1, P=0.001), and PMN-activation (MPO, P<0.001; elastase P=0.007).

CONCLUSION

Severe peritonitis produces an early pulmonary expression of chemoattractants creating a gradient for PMN sequestration and activation into the lung. These parameters are associated with expression of apoptosis in the lung, which is increased in nonsurviving peritonitis patients.

Right-to-left ventricular diastolic delay in chronic thromboembolic pulmonary hypertension is associated with activation delay and action potential prolongation in right ventricle

BACKGROUND

Delayed left ventricle (LV)-to-right ventricle (RV) peak shortening results in cardiac output reduction in patients with chronic thromboembolic hypertension (CTEPH) and other types of pulmonary arterial hypertension. Why the synchrony between LV and RV is lost is unknown. We hypothesized that RV electrophysiological remodeling, notably, conduction slowing and action potential prolongation, contribute to this loss in synchrony.

METHODS AND RESULTS

We conducted epicardial mapping during pulmonary endarterectomy in 26 patients with CTEPH and compared these findings with clinical, hemodynamic, and echocardiographic variables. We consecutively placed a multielectrode grid on the epicardium of the RV free wall and LV lateral wall. These regions corresponded to RV and LV areas where echocardiographic Doppler sample volumes were placed to measure RV-to-LV diastolic interventricular delay. RV and LV epicardial action potential duration was assessed by measuring activation-recovery interval. Onset of diastolic relaxation of RV free wall with respect to LV lateral wall (diastolic interventricular delay) was delayed by 38+/-31 ms in patients with CTEPH versus -12+/-13 ms in control subjects (P<0.001), because, in patients with CTEPH, RV completed electric activation later than LV (65+/-20 versus 44+/-7 ms, P<0.001) and epicardial action potential duration, as assessed by activation-recovery interval measurement, was longer in RV free wall than in LV lateral wall (253+/-29 versus 240+/-22 ms, P<0.001).

CONCLUSIONS

Additive effects of electrophysiological changes in RV, notably, conduction slowing and action potential prolongation, assessed by epicardial activation-recovery interval, contribute to diastolic interventricular delay in patients with CTEPH.

Priming of alveolar macrophages upon instillation of lipopolysaccharide in the human lung

The airways are continuously exposed to respiratory pathogens, which may result in bacterial pneumonia, one of the most common infectious diseases and the leading cause of sepsis. Considering that recurrent exposure to microbial products can lead to tolerance of immune cells, and that this might contribute to the susceptibility to nosocomial infection, we investigated the effect of in vivo lipopolysaccharide (LPS) instillation on the responsiveness of alveolar macrophages. In eight healthy humans, sterile saline was instilled into a lung segment by bronchoscope, followed by instillation of LPS into the contralateral lung; 6 hours later, a bilateral bronchoalveolar lavage was performed, and purified alveolar macrophages were ex vivo stimulated with LPS or lipoteichoic acid (LTA), triggering Toll-like receptor (TLR)-4 and -2, respectively. In vivo LPS-exposed alveolar macrophages were primed, as reflected by increased ex vivo LPS- and LTA-induced IL-1 beta and IL-6 gene expression and production compared with in vivo saline-exposed alveolar macrophages. LPS instillation did not influence the surface expression of TLR4 or TLR2. Furthermore, LPS instillation did not impact on the expression of a number of extracellular and intracellular regulators of TLR signaling. However, p38 mitogen-activated protein kinase remained phosphorylated in alveolar macrophages upon LPS instillation. The current data demonstrate that LPS instillation in the human lung primes alveolar macrophages for further stimulation with either LPS or LTA, possibly by sustained p38 mitogen-activated protein kinase activation.

Effect of bosentan on exercise capacity and quality of life in adults with pulmonary arterial hypertension associated with congenital heart disease with and without Down's syndrome

Pulmonary arterial hypertension associated with congenital heart disease caused by systemic-to-pulmonary shunting was associated with a high risk of morbidity and mortality. In this retrospective study, the longer term treatment effect of bosentan on exercise capacity and quality of life (QoL) were evaluated in 58 adult patients (>18 years) with pulmonary arterial hypertension associated with congenital heart disease, including patients with Down's syndrome. All patients were evaluated at baseline and during follow-up using laboratory tests, 6-minute walk test, QoL questionnaires, and Doppler echocardiography. Treatment efficacy was analyzed separately for patients without (n = 30) and with Down's syndrome (n = 28). Median follow-up of all patients treated with bosentan was 22 months (range 3 to 36). In patients without Down's syndrome, mean 6-minute walk distance increased from 427 +/- 97 to 461 +/- 104 m (p <0.01) after 6 months of treatment, followed by a gradual return to baseline and disease stabilization. QoL improved significantly during treatment and was maintained during 18 months of follow-up (p <0.05). In patients with Down's syndrome, 6-minute walk distance and QoL were stable during treatment. In conclusion, findings suggested that in patients without Down's syndrome, longer term bosentan treatment resulted in a persistent improvement in QoL and stabilization of exercise capacity.

Mechanisms for cardiac output augmentation in patients with a systemic right ventricle

BACKGROUND

Conflicting data have been published on the differences in cardiac response to exercise between patients with an atrially switched transposition of the great arteries (TGA), and patients with a congenitally corrected TGA (ccTGA). The purpose of our study was to evaluate the differences in cardiac response to exercise in these 2 patient groups with a systemic right ventricle (RV).

METHODS

Thirty four patients (62% male; mean 35, range 21-69 years) with a systemic RV (20 with an atrially switched TGA and 14 with a ccTGA) were included. Exercise tests with Portapres measurements were performed to assess maximal exercise capacity (V'O(2peak)), cardiac index, stroke volume index, and heart rate augmentation. Cardiac function was assessed by Cardiovascular Magnetic Resonance or Computed Tomography, and serum NT-proBNP levels.

RESULTS

We found that both groups were able to significantly augment cardiac index during exercise. Cardiac index augmentation during exercise was positively related to V'O(2peak) (r=0.37, p<0.05), and independent of resting cardiac function. Although the increase in cardiac index during exercise was similar in both patients with TGA and with ccTGA, mechanisms to achieve this increase differed between groups. ccTGA patients increased both stroke volume and heart rate during exercise. Atrially switched TGA patients augmented heart rate during exercise, but failed to increase stroke volume.

CONCLUSION

Mechanisms to achieve cardiac output augmentation differ between ccTGA patients and TGA patients. We suggest that therapeutic approaches should be tailored to the specific patient group to avoid counterproductive effects.

Reduced risk of next exacerbation and mortality associated with antibiotic use in COPD

The long-term risk of a subsequent exacerbation of chronic obstructive pulmonary disease (COPD) after treatment with oral corticosteroids without (OS) or with antibiotics (OSA) was compared in a historical general practice-based cohort. Eligible patients were >/=50 yrs of age, had a registered diagnosis of COPD, were on maintenance respiratory drugs, and had experienced at least one exacerbation defined as a prescription OS or OSA. Times to second and third exacerbations were assessed using Kaplan-Meier survival analysis; the risk of a subsequent exacerbation was assessed in a Cox proportional hazards analysis; and all-cause mortality was assessed using Kaplan-Meier survival and Cox proportional hazards analyses. A total of 842 patients had one or more exacerbations. The median time from first to second exacerbation was comparable for the OS and OSA groups, but the time from second to third exacerbation differed: 189 versus 258 days, respectively. The protective effect of OSA was most pronounced during the first 3 months following treatment (hazards ratio 0.72, 95% confidence interval 0.62-0.83). Exposure to antibiotics unrelated to a course of oral corticosteroids almost halved the risk of a new exacerbation. Mortality during follow-up was considerably lower in the OSA group. Adding antibiotics to oral corticosteroids was associated with: reduced risk of subsequent exacerbation, particularly in patients with recurrent exacerbations; and reduced risk of all-cause mortality.

Antibiotic treatment is associated with reduced risk of a subsequent exacerbation in obstructive lung disease: an historical population based cohort study

OBJECTIVES

The risk of a subsequent exacerbation after treatment of an exacerbation with oral corticosteroids without (OS) or with (OSA) antibiotics was evaluated in a historical population based cohort study comprising patients using maintenance medication for obstructive lung disease.

METHODS

The Pharmo database includes drug dispensing records of more than 2 million subjects in The Netherlands. Eligible were patients >or=50 years who in 2003 were dispensed >or=2 prescriptions of daily used inhaled beta(2) agonists, anticholinergics and/or corticosteroids, and experienced at least one exacerbation before 1 January 2006. Exacerbation was defined as a prescription of OS or OSA. The times to the second and third exacerbations were compared using Kaplan-Meier survival analysis. Independent determinants of new exacerbations were identified using multivariable Cox recurrent event survival analysis.

RESULTS

Of 49,599 patients using maintenance medication, 18 928 had at least one exacerbation; in 52%, antibiotics had been added. The OS and OSA groups were comparable for potential confounding factors. Median time to the second exacerbation was 321 days in the OS group and 418 days in the OSA group (p<0.001); and between the second and third exacerbation 127 vs 240 days (p<0.001). The protective effect of OSA was most pronounced during the first 3 months following treatment (hazard ratio (HR) 0.62; 99% CI 0.60 to 0.65). In the OSA group, mortality during follow-up was lower (HR 0.82; 99% CI 0.66 to 0.98).

CONCLUSION

Treatment with antibiotics in addition to oral corticosteroids was associated with a longer time to the next exacerbation, and a decreased risk of developing a new exacerbation.