Ralf Ewert

Assessment of Survival in Patients With Primary Pulmonary Hypertension Importance of Cardiopulmonary Exercise Testing

Background—Primary pulmonary hypertension (PPH) is a life-threatening disease. Prognostic assessment is an important factor in determining medical treatment and lung transplantation. Whether cardiopulmonary exercise testing data predict survival has not been reported previously. Methods and Results—We studied 86 patients with PPH (58 female, age 46±2 years, median NYHA class III) between 1996 and 2001 who were followed up in a tertiary referral center. Right heart catheterization was performed and serum uric acid levels were measured in all patients. Seventy patients were able to undergo exercise testing. At the start of the study, the average pulmonary artery pressure was 60±2 mm Hg, average pulmonary vascular resistance was 1664±81 dyne · s · cm−5, average serum uric acid level was 7.5±0.35 mg/dL, and average peak oxygen uptake during exercise (peak &OV0312;o2) was 11.2±0.5 mL · kg−1 · min−1. During follow-up (mean: 567±48 days), 28 patients died and 16 underwent lung transplantation (1-year cumulative event-free survival: 68%; 95% CI 58 to 78). The strongest predictors of impaired survival were low peak &OV0312;o2 (P <0.0001) and low systolic blood pressure at peak exercise (peak SBP;P <0.0001). In a multivariable analysis, serum uric acid levels (all P <0.005) and diastolic blood pressure at peak exercise independently predicted survival (P <0.05). Patients with peak &OV0312;o2 ≤10.4 mL · kg−1 · min−1 and peak SBP ≤120 mm Hg (ie, 2 risk factors) had poor survival rates at 12 months (23%), whereas patients with 1 or none of these risk factors had better survival rates (79% and 97%, respectively). Conclusions—Peak &OV0312;o2 and peak SBP are independent and strong predictors of survival in PPH patients. Hemodynamic parameters, although also accurate predictors, provide no independent prognostic information.

Cytomegalovirus (CMV) phosphoprotein 65 makes a large contribution to shaping the T cell repertoire in CMV-exposed individuals

Antigen-specific, cytokine flow cytometry was used to analyze the prevalence and frequency of CD4 and CD8 memory T cells specific for the abundantly expressed cytomegalovirus (CMV) phosphoprotein 65 (pp65) in healthy CMV IgG-seropositive individuals. Stimulation of peripheral blood mononuclear cells with peptide pools and individual peptides derived from the pp65 amino acid sequence in 40 donors revealed that 63% of donors had a detectable CD4 T cell response and that 83% of donors had a detectable CD8 T cell response against this protein. The overall frequencies of T cells directed against pp65 were analyzed for 20 donors by stimulation with peptide pools covering the complete pp65 protein and were as high as 2 in 1000 and 9 in 1000 (median) peripheral blood CD4 and CD8 T cells, respectively. In addition, a comparison between CD4 responses to a CMV lysate containing various CMV proteins and pp65-specific responses in 9 donors indicated that pp65 was a dominant target of the CMV-specific CD4 T cell response in some, but not all, donors. Several new T cell epitopes were identified.

Riociguat for chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension: a phase II study

We assessed the therapeutic potential of riociguat, a novel soluble guanylate cyclase stimulator, in adults with chronic thromboembolic pulmonary hypertension (CTEPH; n = 42) or pulmonary arterial hypertension (PAH; n = 33) in World Health Organization (WHO) functional class II/III. In this 12-week, multicentre, open-label, uncontrolled phase II study, patients received oral riociguat 1.0–2.5 mg t.i.d. titrated according to systemic systolic blood pressure (SBP). Primary end-points were safety and tolerability; pharmacodynamic changes were secondary end-points. Riociguat was generally well tolerated. Asymptomatic hypotension (SBP <90 mmHg) occurred in 11 patients, but blood pressure normalised without dose alteration in nine and after dose reduction in two. Median 6-min walking distance increased in patients with CTEPH (55.0 m from baseline (390 m); p<0.0001) and PAH (57.0 m from baseline (337 m); p<0.0001); patients in functional class II or III and bosentan pre-treated patients showed similar improvements. Pulmonary vascular resistance was significantly reduced by 215 dyn·s·cm−5 from baseline (709 dyn·s·cm−5; p<0.0001). 42 (56%) patients were considered to have experienced drug-related adverse events (AEs; 96% mild or moderate). Dyspepsia, headache and hypotension were the most frequent AEs. Study discontinuation because of AEs was 4%. These preliminary data show that riociguat has a favourable safety profile and improves exercise capacity, symptoms and pulmonary haemodynamics in CTEPH and PAH. Randomised controlled trials are underway.

Anticoagulation and Survival in Pulmonary Arterial Hypertension

Background— For almost 30 years, anticoagulation has been recommended for patients with idiopathic pulmonary arterial hypertension (IPAH). Supporting evidence, however, is limited, and it is unclear whether this recommendation is still justified in the modern management era and whether it should be extended to patients with other forms of pulmonary arterial hypertension (PAH). Methods and Results— We analyzed data from Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA), an ongoing European pulmonary hypertension registry. Survival rates of patients with IPAH and other forms of PAH were compared by the use of anticoagulation. The sample consisted of 1283 consecutively enrolled patients with newly diagnosed PAH. Anticoagulation was used in 66% of 800 patients with IPAH and in 43% of 483 patients with other forms of PAH. In patients with IPAH, there was a significantly better 3-year survival (P=0.006) in patients on anticoagulation compared with patients who never received anticoagulation, albeit the patients in the anticoagulation group had more severe disease at baseline. The survival difference at 3 years remained statistically significant (P=0.017) in a matched-pair analysis of n=336 IPAH patients. The beneficial effect of anticoagulation on survival of IPAH patients was confirmed by Cox multivariable regression analysis (hazard ratio, 0.79; 95% confidence interval, 0.66–0.94). In contrast, the use of anticoagulants was not associated with a survival benefit in patients with other forms of PAH. Conclusions— The present data suggest that the use of anticoagulation is associated with a survival benefit in patients with IPAH, supporting current treatment recommendations. The evidence remains inconclusive for other forms of PAH. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01347216.BACKGROUND: For almost 30 years, anticoagulation has been recommended for patients with idiopathic pulmonary arterial hypertension (IPAH). Supporting evidence, however, is limited, and it is unclear whether this recommendation is still justified in the modern management era and whether it should be extended to patients with other forms of pulmonary arterial hypertension (PAH). METHODS AND RESULTS: We analyzed data from COMPERA, an ongoing European pulmonary hypertension registry. Survival rates of patients with IPAH and other forms of PAH were compared by the use of anticoagulation. The sample consisted of 1,283 consecutively enrolled patients with newly diagnosed PAH. Anticoagulation was used in 66% of 800 patients with IPAH and in 43% of 483 patients with other forms of PAH. In patients with IPAH, there was a significantly better 3-year-survival (p=0.006) in patients on anticoagulation compared to patients who never received anticoagulation, albeit the patients in the anticoagulation group had more severe disease at baseline. The survival difference at 3 years remained statistically significant (p=0.017) in a matched-pair analysis of n=336 IPAH patients. The beneficial effect of anticoagulation on survival of IPAH patients was confirmed by Cox multivariable regression analysis (hazard ratio 0.79, 95% confidence interval 0.66 to 0.94). In contrast, the use of anticoagulants was not associated with a survival benefit in patients with other forms of PAH. CONCLUSIONS: The present data suggest that the use of anticoagulation is associated with a survival benefit in patients with IPAH, supporting current treatment recommendations. The evidence remains inconclusive for other forms of PAH. CLINICAL TRIALS REGISTRATION INFORMATION: www.clinicaltrials.gov. Identifier: NCT01347216.

Reference values for cardiopulmonary exercise testing in healthy volunteers: the SHIP study

Cardiopulmonary exercise testing (CPET) is a widely applied clinical procedure. The aim of the present study was to acquire a comprehensive set of reference values for cardiopulmonary responses to exercise and to evaluate possible associations with sex, age and body mass index (BMI). A standardised progressive incremental exercise protocol on a cycle ergometer was applied to 1,708 volunteers of a cross-sectional epidemiologic survey, called “Study of Health in Pomerania”. Individuals with cardiopulmonary disorders, or echocardiographic or lung function pathologies, were excluded. The influence of potential confounding factors, such as smoking, taking β-blockers, hypertension, diastolic dysfunction, BMI and physical activity, were analysed for their influencing power. Reference values of CPET parameters were determined by regression analyses. Of the volunteers, 542 current smokers and obese individuals were excluded for not being representative of a healthy population. The final sample size was 534 (253 males), with age 25–80 yrs. The current study provides a representative set of reference values for CPET parameters based on age and weight. Sex and age have a significant influence on exercise parameters. While addressing the problem of a selection bias, the current study provides the first comprehensive set of reference values obtained in a large number of healthy volunteers within a population-based survey.

Inhibition of endothelin receptors in the treatment of pulmonary arterial hypertension: does selectivity matter?

Treatment options for pulmonary arterial hypertension (PAH) have considerably improved in the past few years. Endothelin (ET)-receptor antagonism has been established as a first-line option for the majority of PAH patients. Endothelin-receptor antagonists (ETRAs) comprise sulfonamide and non-sulfonamide agents with different affinities for ET-receptor subtypes (ET(A) and ET(B)), and the focus of development has shifted from drugs with less selectivity to those with high selectivity. There is ongoing debate as to whether selective or non-selective ET-receptor antagonism is more beneficial in the treatment of PAH. This paper reviews the current evidence from experimental and clinical studies obtained from a thorough literature search focusing on the three marketed drugs bosentan, sitaxentan, and ambrisentan. A clinically meaningful difference among the three approved ETRAs with respect to their ET-receptor selectivity could not be demonstrated to date. Therefore, in clinical practice, other features are likely to be of greater relevance when considering treatment, such as the potential for serious drug-drug interactions, convenience of dosing schedule, or rates of limiting side effects. These characteristics bear more relation to the chemical or pharmacological properties of the drugs than to receptor selectivity itself.

Impaired cardiac autonomic control relates to disease severity in pulmonary hypertension

Pulmonary arterial hypertension (PAH) results in chronic right heart failure, which is associated with an increase in sympathetic tone. This may adversely affect cardiac autonomic control. We investigated the changes in cardiac autonomic nervous activity in relation to disease severity in patients with PAH. In 48 patients with PAH (median World Health Organization class III, pulmonary artery pressure 52±14 mmHg, pulmonary vascular resistance 1,202±718 dyn·s·cm−5, cardiac index 2.0±0.8 L·min−1·m−2) and 41 controls, cardiac autonomic nervous activity was evaluated by measurement of heart rate variability (HRV) and baroreflex sensitivity. All patients underwent cardiopulmonary exercise testing (peak oxygen uptake 13.2±5.1 mL·kg−1·min−1, minute ventilation/carbon dioxide production slope 47±16). In patients with PAH, spectral power of HRV was reduced in the high-frequency (239±64 versus 563±167 ms2), low-frequency (245±58 versus 599±219 ms2) and very low-frequency bands (510±149 versus 1106±598 ms2; all p<0.05). Baroreflex sensitivity was also blunted (5.8±0.6 versus 13.9±1.2 ms·mmHg−1; p<0.01). The reduction in high-frequency (r = 0.3, p = 0.04) and low-frequency (r = 0.33, p = 0.02) spectral power and baroreflex sensitivity (r = 0.46, p<0.01) was related to the reduction in peak oxygen uptake. Patients with PAH have a marked alteration in cardiac autonomic control that is related to exercise capacity and may, therefore, serve as an additional marker of disease severity.

Assessment of the vasodilator response in primary pulmonary hypertension Comparing prostacyclin and iloprost administered by either infusion or inhalation

AIMS To directly compare the differential effects of oxygen, prostacyclin and iloprost (aerosolized and intravenous) in primary pulmonary hypertension. METHODS AND RESULTS Twenty-one patients with severe primary pulmonary hypertension underwent right heart catheterization following oxygen inhalation, inhalation of aerosolized iloprost, intravenous prostacyclin or intravenous iloprost. The stability of the iloprost solution was tested for up to 4 weeks. Oxygen slightly decreased pulmonary vascular resistance. Intravenous prostacyclin (7.2+/-3.4 ng kg(-1) min(-1)) reduced pulmonary (1772+/-844 vs 1325+/-615 dyn s cm(-5), P<0.001) and systemic vascular resistance, and arterial and right atrial pressure, while cardiac output increased. Iloprost inhalation diminished pulmonary (1813+/-827 vs 1323+/-614 dyn s cm(-5), P<0.001) and systemic vascular resistance, and pulmonary artery (58+/-12 vs 50+/-12 mmHg,P<0.001) and right atrial pressure, while cardiac output increased. With intravenous iloprost (1.2+/-0.5 ng kg(-1) min(-1), n=8) a decrease in pulmonary (2202+/-529 vs 1515+/-356 dyn s cm(-5), P<0.05) and systemic vascular resistance and right a trial pressure occurred while cardiac output increased. Iloprost solution remained stable for 33 days while losing <10% (4 degrees C) of its active drug concentration.Conclusions Intravenous iloprost and prostacyclin have very similar haemodynamic profiles. In contrast, only inhaled iloprost exerted selective pulmonary vasodilation, reducing pulmonary vascular resistance and pulmonary artery pressure without systemic vasodilation. The longer half-life and extended stability despite lower costs render iloprost an attractive alternative to chronic prostacyclin treatment in primary pulmonary hypertension.

Long-term outcome with intravenous iloprost in pulmonary arterial hypertension

There is limited data on the long-term efficacy of intravenous iloprost in patients with pulmonary arterial hypertension (PAH). This retrospective multicentre analysis evaluated the clinical course of patients with PAH treated with i.v. iloprost, in most cases after having received inhaled iloprost as first-line therapy. Between 1997 and 2001, 79 PAH patients were treated with i.v. iloprost and followed until 2007. These patients had advanced and progressive disease as indicated by a mean pulmonary vascular resistance of 1,533 dyn·s·cm−5 at the time of diagnosis and of 1,858 dyn·s·cm−5 at the onset of i.v. iloprost therapy. Introduction of i.v. iloprost therapy resulted in initial haemodynamic and clinical improvement. At the end of the observation period, however, 50 (61%) patients had died and 21 (26%) required lung transplantation. Transplantation-free survival rates at 1, 3, and 5 yrs were 86%, 59% and 45%, respectively, after the diagnosis of PAH, and 54%, 31% and 15%, respectively, after the introduction of i.v. iloprost therapy. Predictors of an adverse outcome at baseline were a low 6-min walk distance and a low mixed venous oxygen saturation. In conclusion, despite initial haemodynamic and clinical improvement, overall long-term survival with i.v. iloprost therapy was limited.

Plasmapheresis and cyclophosphamide in the treatment of humoral rejection after heart transplantation.

BACKGROUND Clinical reports on humoral rejection after heart transplantation showed that these episodes were often more severe than those mediated through T lymphocytes and that the patients prognosis was significantly worsened. METHODS To evaluate the impact of plasmapheresis on the course of humoral rejection with hemodynamic compromise (HRHC) episodes, we retrospectively investigated the records of 1,108 heart transplant patients. All patients received triple-drug immunosuppression (cyclosporine a, azathioprine, prednisone) and cytolytic antibodies for induction. Between April 1986 and December 1990, HRHC episodes were treated with cortisone boli and cytolytic antibodies for at least 3 days (Group A). Between January 1991 and April 1999, HRHC episodes were treated with cortisone boli, cytolytic antibodies, and plasmapheresis for at least 3 days (Group B). All patients who survived their first HRHC episode received cyclophosphamide instead of azathioprine as maintenance immunosuppression. RESULTS Altogether we observed 29 HRHC episodes. In 11 cases, no therapy could be administered or the therapy regimen did not correspond to either Protocol A or B. In the remaining 18 HRHC episodes, 7 episodes in 7 patients were treated without plasmapheresis (Group A), but only 2 patients survived, whereas in 11 HRHC episodes in 6 patients, therapy included plasmapheresis (Group B) and all patients survived (p = 0.002). Four of 6 patients who received cyclophosphamide after their first HRHC episode experienced at least 1 further HRHC episode. CONCLUSIONS Plasmapheresis seems to improve outcomes in HRHC. However, cyclophosphamide as a maintenance immunosuppressive drug failed to prevent further humoral rejection episodes.