Diagnostik und Therapie der pulmonalen Hypertonie: Europäische Leitlinien 2009

Variables Influencing the Pressure and Volume of the Pulmonary Circulation as Risk Factors for Developing High Altitude Pulmonary Edema (HAPE)

BACKGROUND

At altitudes above 2500 m, the risk of developing high altitude pulmonary edema (HAPE) grows with the increases in pulmonary arterial pressure. HAPE is characterized by severe pulmonary hypertension, though the incidence and relevance of individual risk factors are not yet predictable. However, the systolic pulmonary pressure (SPAP) and peak in tricuspid regurgitation velocity (TVR) are crucial factors when diagnosing pulmonary hypertension by echocardiography.

METHODS

The SPAP and TVR of 27 trekkers aged 20-65 years en route to the Solu Khumbu region of Nepal were assessed. Echocardiograph measurements were performed at Lukla (2860 m), Gorak Shep (5170 m), and the summit of Kala Patthar (5675 m). The altitude profile and the participants' characteristics were also compiled for correlation with the measured data.

RESULTS

The results showed a highly significant increase in SPAP and TVR after ascending Kala Patthar. The study revealed a lower increase of SPAP and TVR in the group of older participants, although the respective initial measurements at Gorak Shep were significantly higher for this group. A similar finding occurred in those using Diamox^® as prophylaxis. There was an inverse relationship between TVR and SPAP, the peripheral capillary oxygen saturation, and heart rate.

CONCLUSIONS

The echocardiograph results indicated that older people are an at-risk group for developing HAPE. A conservative interpretation of the basic tactical rules for altitudes should be followed for older trekkers or trekkers with known problems of altitude acclimatization ("slow acclimatizer") as SPAP elevates with age. The prophylactic use of Acetazolamide (Diamox^®) should be avoided where not necessary for acute medical reasons. Acetazolamide leads to an increase of SPAP, and this may potentially enhance the risk of developing HAPE. Arterial oxygen saturation measurements can provide an indicator for the self-assessment for the risk of developing HAPE and a rule of thumb for the altitude profile, but does not replace a HAPE diagnosis. Backpack weight, sex, workload (actual ascent speed), and pre-existing diseases were not statistically significant factors related to SPAP and TVR (p ≤ 0.05).

Plasma miR-451 with echocardiography serves as a diagnostic reference for pulmonary hypertension

Due to the lack of typical clinical symptoms, the average delay time for diagnosis of pulmonary hypertension (PH) is longer than 2 years. It is urgent to find biomarkers for PH diagnosis. In this study we investigated whether plasma microRNAs (miRNAs) can be used as biomarkers for PH diagnosis. We used microarray to identify dynamic miRNAs between PH and non-PH patients. The candidate miRNAs were verified using qRT-PCR in a mouse model of PH, which was induced by monocrotaline (MCT) injection. We observed that miR-21, miR-126, miR-145, miR-191 and miR-150 had no differences between control mice and MCT-treated mice; but plasma miR-451 was significantly decreased in the 2wk-MCT group, with no further decrease in the 4wk-MCT group. Plasma miR-451 was also markedly decreased in PH patients, whereas miR-21, miR-126, miR-150 and miR-320 did not show differences between 53 PH patients and 54 non-PH patients. Receiver operating characteristic curves (ROCs) were constructed from the patient data to assess the clinical diagnostic values of circulating miR-451 and Doppler echocardiography (D-ECHO). The areas under the curve (AUCs) of ROCs for miR-451 and D-ECHO were 0.710 and 0.766, respectively. Combination of miR-451 and D-ECHO with AUC of 0.825 was superior to the use of either miR-451 or D-ECHO alone for PH diagnosis. In conclusion, plasma miR-451 has a moderate diagnostic value in PH comparable to that of D-ECHO, and the combination of miR-451 with D-ECHO has better diagnostic value than either method alone, which may have implications for PH diagnosis.

The sGC stimulator riociguat inhibits platelet function in washed platelets but not in whole blood

BACKGROUND AND PURPOSE

Stimulation of soluble guanylyl cyclase (sGC) is a valuable therapeutic strategy for the treatment of several cardiovascular diseases. The sGC stimulator riociguat has been approved for the treatment of two forms of pulmonary hypertension. Platelets contain large amounts of sGC and play a key role in the regulation of haemostasis. Therefore, we investigated the effects of riociguat on platelet function.

EXPERIMENTAL APPROACH

The effect of riociguat treatment on human platelet activation and aggregation was investigated. The sGC-specific effects of riociguat were determined by comparing wild-type and platelet-specific sGC-knockout mice.

KEY RESULTS

Riociguat induced cGMP synthesis and subsequent PKG activation in human platelets, suggesting that the inhibitory effects are mediated by cGMP signalling. This finding was confirmed when sGC-knockout platelets were not inhibited by riociguat. In washed human platelets, 100 nM riociguat reduced ADP-induced GPIIb/IIIa activation, while a 10-fold higher concentration was required to reduce convulxin-stimulated GPIIb/IIIa activation. Riociguat inhibited ADP-induced platelet shape change and aggregation, while ATP-induced shape change remained unaffected. However, in PRP and whole blood, 50-100 μM riociguat was required to inhibit platelet activation and aggregation. Riociguat in combination with iloprost significantly inhibited platelet aggregation, even in whole blood.

CONCLUSIONS AND IMPLICATIONS

Riociguat inhibits platelet activation in whole blood only at concentrations above 50 μM, while the plasma concentrations in riociguat-treated patients are 150 to 500 nM. This finding indicates that riociguat treatment does not affect platelet function in patients. Nevertheless, the possibility that riociguat acts synergistically with iloprost to inhibit platelet activation should be considered.

Anti-endothelial cell antibodies in connective tissue diseases associated with pulmonary arterial hypertension

OBJECTIVE

To investigate the prevalence of anti-endothelial cell antibodies (AECA) in connective tissue diseases (CTD) associated with pulmonary arterial hypertension (PAH) and to corroborate the pathologic function of AECA in PAH-associated CTDs.

METHODS

AECA were detected by cellular enzyme-linked immunosorbent assay (ELISA) in sera of 19 PAH-associated CTD patients, 22 CTD patients without PAH involvement, and 20 age- and sex-matched healthy individuals as controls. Using IgG purified from the sera of AECA-positive, AECA-negative, and healthy subjects, the effects of AECA on the expression of ICAM-1 and the chemokine regulated upon activation normal T-cell expressed and secreted (RANTES) in cultured endothelial cells were also evaluated.

RESULTS

A total of 12 of the 19 (63.2%) CTD patients with PAH, 9 of the 22 (40.9%) CTD patients without PAH, and 1 of the 20 (5%) healthy controls were positive for AECA, which were calculated as ELISA ratio (ER) values. ER values in PAH-associated CTD patients were significantly higher than those with CTD without PAH (3.68±2.05 versus 1.67±1.07, P<0.001). IgG purified from AECA-positive sera induced a significantly increased level of ICAM-1 expression after 48 h incubation (795.2±32.5 pg/mL) compared with AECA-negative or healthy control IgG (231.5±27.1 and 192.8±33.4 pg/mL, respectively; P<0.001). In addition, RANTES production by cultured human pulmonary arterial endothelial cells (HPAECs) increased in both a time- and concentration-dependent manner in response to incubation with purified AECA-positive IgG.

CONCLUSIONS

AECA could be involved in CTD and might participate in the pathogenesis of PAH-associated CTD.

Pulmonary hypertension: Hemodynamic evaluation. Updated Recommendations of the Cologne Consensus Conference 2011

The 2009 European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension have been adopted for Germany. The guidelines contain detailed recommendations for the diagnosis of pulmonary hypertension. However, the practical implementation of the European Guidelines in Germany requires the consideration of several country-specific issues and already existing novel data. This requires a detailed commentary to the guidelines, and in some aspects an update already appears necessary. In June 2010, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany. This conference aimed to solve practical and controversial issues surrounding the implementation of the European Guidelines in Germany. To this end, a number of working groups was initiated, one of which was specifically dedicated to the invasive hemodynamic evaluation of pulmonary hypertension. This manuscript describes in detail the results and recommendations of the working group which were last updated in October 2011.

Pulmonary hypertension due to chronic lung disease: updated Recommendations of the Cologne Consensus Conference 2011

The 2009 European Guidelines on Pulmonary Hypertension did not cover only pulmonary arterial hypertension (PAH) but also some aspects of pulmonary hypertension (PH) in chronic lung disease. These guidelines point out that the drugs currently used to treat patients with PAH (prostanoids, endothelin receptor antagonists and phosphodiesterase type-5 inhibitors) have not been sufficiently investigated in other forms of PH. Therefore, the use of these drugs in patients with chronic lung disease and PH is not recommended. This recommendation, however, is not always in agreement with medical needs as physicians feel sometimes inclined to also treat other forms of pulmonary hypertension which may affect the quality of life and survival of these patients in a similar manner as in PAH. In June 2010, a consensus conference was held in Cologne, Germany, to discuss open and controversial issues surrounding the practical implementation of the European Guidelines. The conference was sponsored by the German Society of Cardiology, the German Society of Respiratory Medicine and the German Society of Pediatric Cardiology (DGK, DGP and DGPK). To this end, a number of working groups were initiated, one of which was specifically dedicated to the diagnosis and treatment of PH due to chronic lung disease. This manuscript describes in detail the results and recommendations of this working group which were last updated in October 2011.

Chronic thromboembolic pulmonary hypertension (CTEPH): updated Recommendations of the Cologne Consensus Conference 2011

In the 2009 European Guidelines on the diagnosis and treatment of pulmonary hypertension (PH), one section covers aspects of pathophysiology, diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). The practical implementation of the guidelines for this disease is of crucial importance, because CTEPH is a subset of PH which can potentially be cured by pulmonary endarterectomy (PEA). Nowadays, CTEPH is commonly underdiagnosed and not properly managed. Any patient with unexplained PH should be evaluated for the presence of CTEPH, and a ventilation/perfusion (V/Q) lung scan is recommended as screening method of choice. If the V/Q scan or CT angiography reveals signs of CTEPH, the patient should be referred to a specialized center with expertise in the medical and surgical management of this disease. Every case has to be reviewed by an experienced PEA surgeon for the assessment of operability. In this updated recommendation, important contents of the European guidelines were commented, and more recent information regarding diagnosis and treatment was added.

Pulmonary hypertension due to left heart disease: updated Recommendations of the Cologne Consensus Conference 2011

The 2009 European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension (PH) have been adopted for Germany. While the guidelines contain detailed recommendations regarding pulmonary arterial hypertension (PAH), they contain only a relatively short paragraph on other, much more frequent forms of PH including PH owing to left heart disease. The guidelines point out that the drugs currently used to treat patients with PAH (prostanoids, endothelin receptor antagonists and phosphodiesterase type 5 inhibitors) have not been sufficiently investigated in other forms of PH. However, despite the lack of respective efficacy data an uncritical use of targeted PAH drugs in patients with PH associated with left heart disease is currently observed at an increasing rate. This development is a matter of concern. On the other hand, PH is a frequent problem that is highly relevant for morbidity and mortality in patients with left heart disease. It that sense, the practical implementation of the European Guidelines in Germany requires the consideration of several specific issues and already existing novel data. This requires a detailed commentary to the guidelines, and in some aspects an update already appears necessary. In June 2010, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany. This conference aimed to solve practical and controversial issues surrounding the implementation of the European Guidelines in Germany. To this end, a number of working groups was initiated, one of which was specifically dedicated to PH due to left heart disease. This commentary describes in detail the results and recommendations of the working group which were last updated in October 2011.