[Pulmonary arterial hypertension in collagenoses]

Pulmonary arterial hypertension is a rare disease of small pulmonary arteries of unknown origin characterised by endothelial dysfunction and cellular proliferation throughout all vessel layers, resulting in progressively elevated pulmonary arterial resistance with increasing right heart strain and finally right heart failure. The condition may develop in connective tissue diseases with variable frequency leading to a substantial worsening of prognosis. However, the spectrum of therapeutic options has broadened significantly in recent years. Several compounds have gained approval that act mainly as pulmonary vasodilators. Further drugs are under investigation, some of which target pulmonary vascular remodeling. Echocardiography remains the primary examination for disease detection. To classify pulmonary hypertension definite hemodynamic evaluation by means of right heart catheterisation and a thorough differential diagnosis are essential to provide the basis for further treatment. For differential therapy and assessment of follow-up profound knowledge is required, pointing to the need for close cooperation with specialised centres.

[Update: Current clinical developments in pulmonary hypertension]

During the last years, therapeutic options for the treatment of pulmonary arterial hypertension (PAH) have significantly improved. However, the therapeutic concept depends on the etiology of the disease, so that an exact classification is mandatory. Currently, three substance classes are approved for the treatment of PAH (Group I of the Venice Classification): Endothelin receptor antagonists, phosphodiesterase type-5 inhibitors, and prostanoids. After the World Conference in Dana Point (2008), recent changes in therapeutic strategies comprise the early treatment of the disease, as well as the increased importance of an early use of combination therapy if treatment goals are not met. Several new substances are currently evaluated in clinical trials. The soluble guanylate cyclase (sGC) stimulators achieve potent, NO-independent vasodilation. Another promising pathophysiological approach is currently evaluated by the use of tyrosine kinase inhibitors - anti-proliferative drugs which inhibit or even may reverse the pulmonary vascular remodeling process. Serotonin receptor antagonists are also reported to have anti-proliferative, anti-thrombotic and anti-fibrotic effects. Other forms of pulmonary hypertension (Groups II-V) are strictly separated from PAH. Evidence on treatment with PAH specific agents is strongly needed for these groups. Patients with non-PAH pulmonary hypertension should be referred to PAH expert centers, and preferably treated in controlled studies.

[International, prospective register for the documentation of first-line and maintenance therapy in patients with pulmonary hypertension (CompERA-XL)]

In view of the manifold options for mono- and combination therapy that have now emerged for patients with pulmonary (arterial) hypertension (PAH/PH), controlled clinical trials can only provide part of the information needed for optimal management. In order to gather adequate data on PAH/PH treatment in routine clinical care, the ongoing CompERA-XL register prospectively documents consecutive patients with newly initiated treatment of PAH/PAH since May 2007. The internet-based register fulfils high quality standards through several measures (minimum centre contribution of at least 10 patients per year, automated plausibility checks of data at entry, queries, monitoring with source data verification). It can be applied, among further purposes, for quality assurance: individual centers can confidentially compare their results with the combined outcome of other centers and the recommendations from guidelines. The register, currently active in 7 countries, presently follows up 785 patients with any kind of treatment for PH/PAH (now at 626 patient years). It is expected that the register contributes to optimization of specific drug therapy for PAH and PH.

Bridge to thoracic organ transplantation in patients with pulmonary arterial hypertension using a pumpless lung assist device

We describe a novel technique of pumpless extracorporeal life support in four patients with cardiogenic shock due to end-stage pulmonary hypertension (PH) including patients with veno-occlusive disease (PVOD) using a pumpless lung assist device (LAD). The device was connected via the pulmonary arterial main trunk and the left atrium, thereby creating a septostomy-like shunt with the unique addition of gas exchange abilities in parallel to the lung. Using this approach, all four patients were successfully bridged to bilateral lung transplantation and combined heart-lung transplantation, respectively. Although all patients presented in cardiogenic shock, hemodynamic unloading of the right ventricle using the low-resistance LAD stabilized the hemodynamic situation immediately so that no pump support was subsequently required.

Endothelin receptor antagonists in pulmonary arterial hypertension

The endothelin (ET) system, especially ET-1 and the ET(A) and ET(B) receptors, has been implicated in the pathogenesis of pulmonary arterial hypertension (PAH). Together with prostanoids and phosphodiesterase 5 inhibitors, ET receptor antagonists have become mainstays in the current treatment of PAH. Three substances are currently available for the treatment of PAH. One of these substances, bosentan, blocks both ET(A) and ET(B) receptors, whereas the two other compounds, sitaxsentan and ambrisentan, are more selective blockers of the ET(A) receptor. There is ongoing debate as to whether selective or nonselective ET receptor blockade is advantageous in the setting of PAH, although there is no clear evidence that receptor selectivity is relevant with regard to the clinical effects of these drugs. For the time being, other features, such as safety profiles and the potential for pharmacokinetic interactions with other drugs used in the treatment of PAH, may be more important than selectivity or nonselectivity when selecting treatments for individual patients.

Results of European post-marketing surveillance of bosentan in pulmonary hypertension

After the approval of bosentan for the treatment of pulmonary arterial hypertension (PAH), European authorities required the introduction of a post-marketing surveillance system (PMS) to obtain further data on its safety profile. A novel, prospective, internet-based PMS was designed, which solicited reports on elevated aminotransferases, medical reasons for bosentan discontinuation and other serious adverse events requiring hospitalisation. Data captured included demographics, PAH aetiology, baseline functional status and concomitant PAH-specific medications. Safety signals captured included death, hospitalisation, serious adverse events, unexpected adverse events and elevated aminotransferases. Within 30 months, 4,994 patients were included, representing 79% of patients receiving bosentan in Europe. In total, 4,623 patients were naïve to treatment; of these, 352 had elevated aminotransferases, corresponding to a crude incidence of 7.6% and an annual rate of 10.1%. Bosentan was discontinued due to elevated aminotransferases in 150 (3.2%) bosentan-naïve patients. Safety results were consistent across subgroups and aetiologies. The novel post-marketing surveillance captured targeted safety data ("potential safety signals") from the majority of patients and confirmed that the incidence and severity of elevated aminotransferase levels in clinical practice was similar to that reported in clinical trials. These data complement those from randomised controlled clinical trials and provide important additional information on the safety profile of bosentan.

Experience with inhaled iloprost and bosentan in portopulmonary hypertension

Novel treatments, such as prostanoids or endothelin receptor antagonists, have been introduced for various forms of pulmonary arterial hypertension, but the long-term effects of these treatments on portopulmonary hypertension (PPHT) are unknown. In a retrospective analysis, the present authors assessed the safety and efficacy of inhaled iloprost, a prostacyclin analogue, and bosentan, an endothelin receptor antagonist, in patients with PPHT. In total, 31 consecutive patients with Child class A or B cirrhosis and severe PPHT were treated for up to 3 yrs with either inhaled iloprost (n = 13) or bosentan (n = 18), and the effects on exercise capacity, haemodynamics and survival were evaluated. In the iloprost group, the survival rates at 1, 2 and 3 yrs were 77, 62 and 46%, respectively. In the bosentan group, the respective survival rates were 94, 89 and 89%. Event-free survival rates, i.e. survival without transplantation, right heart failure or clinical worsening requiring the introduction of a new treatment for pulmonary hypertension, was also significantly better in the bosentan group. Bosentan had significantly better effects than inhaled iloprost on exercise capacity, as determined by the 6-min walk test, as well as on haemodynamics. Both treatments proved to be safe, especially in regards of liver function. In the present series of patients with well-preserved liver function and severe portopulmonary hypertension, treatment with both inhaled iloprost and bosentan appeared to be safe. Patients treated with bosentan had higher survival rates, but prospective controlled studies are required to confirm these findings.

[Drug combination treatment for pulmonary arterial hypertension]

The clinical condition of patients with chronic pulmonary arterial hypertension (PHT) often deteriorates progressively, despite monotherapy with presently available groups of drugs: prostanoids, endothelin-receptor antagonists and phosphodiesterase-5-inhibitors. In such situations there is in principle the opportunity of giving a combination of drugs, especially as one can expect synergistic effects. Trials with a small number of patients have indicated that the combination of inhaled iloprost and bosentan, inhaled iloprost and sildenafil or bosentan and sildenafil are more efficacious than any one of these drugs taken as monotherapy. The decision when to use a combination treatment should be made on the basis of defined targets that are of significant prognostic value. It should be considered for patients in NYHA class III or IV, if monotherapy has not achieved the desired efficacy. Combination treatment with two or three of the mentioned drugs are being tested as part of controlled studies of their efficacy and safety: they currently constitute the most important therapeutic advances. Analogously to the management of heart failure, combination therapy is likely to be the standard treatment of PHT in future, with the aim of providing optimal results for exertional capacity and lasting functional stability.

[Treatment of pulmonary arterial hypertension: endothelin-receptor antagonists]

Endothelin-1 (ET-1) is of significance in the pathophysiology and prognosis of pulmonary hypertension (PHT). Bosentan, an endothelin-receptor antagonist, currently plays a central role in the treatment of PHT, because it improves exercise capacity, hemodynamics, clinical symptoms and right ventricular function, achieving a survival duration of 2- 3 years. Bosentan causes an increase of transaminases in about 10% of patients, but this effect is reversible on dosage reduction or discontinuing the medication. However, transaminases should be measured every 4 weeks while patients are on bosentan. Almost all current guidelines list bosentan as of equal value to sildenafil or prostacyclin analogues in the first-line treatment of patients in NYHA functional class III and also, with narrower indications, of those in class IV.

[Hospital emergency plan for the management of patients with highly contagious diseases]

Patients with imported highly contagious diseases like viral hemorrhagic fever (VHF), pneumonic plague or anthrax require special preventive measures and strict isolation. In addition, new emerging infections like severe acute respiratory syndrome (SARS) and epidemic influenza also have to be taken into account. At present five high security infectious disease units for patient care are available in Germany. Due to the relatively nonspecific symptoms, a patient with one of these infections may also be admitted to any other hospital. Therefore each hospital should develop a concept for the management and control of these lifethreatening highly contagious diseases. The present article describes the current emergency plan developed for the management of patients with highly contagious diseases at Hannover Medical School.

Prognostic value of blood gas analyses in patients with idiopathic pulmonary arterial hypertension

Blood gas abnormalities in patients with idiopathic pulmonary arterial hypertension (IPAH) may be related to disease severity and prognosis. The present authors performed a 12-yr retrospective analysis assessing arterialised capillary blood gases, haemodynamics, exercise variables and survival in 101 patients with IPAH. At baseline, arterial oxygen tension (P(a,O(2))) and carbon dioxide arterial tension (P(a,CO(2))) were 9.17+/-1.86 and 4.25+/-0.532 kPa, respectively. While P(a,O(2) )was not associated with survival, a low P(a,CO(2 ))was a strong and independent prognostic marker. When patients were divided according to a baseline P(a,CO(2 ))value above or below 4.25 kPa, a cut-off value determined by receiver operating characteristics analysis, survival rates were 98 and 86% at 1 yr, 82 and 69% at 2 years, 80 and 51% at 3 yrs, 77 and 41% at 5 yrs, and 65 and 12% at 8 yrs, respectively. P(a,CO(2 ))after 3 months of medical therapy was strongly associated with survival. Hypocapnia at rest and during exercise correlated with low cardiac output, low peak oxygen uptake and reduced ventilatory efficacy. Multiple regression analysis revealed that 6-min walking distance, right atrial pressure and P(a,CO(2 ))were independently associated with survival. In patients with idiopathic pulmonary arterial hypertension, hypocapnia (carbon dioxide arterial tension <4.25 kPa) is an independent marker of mortality.