Primary pulmonary hypertension and fenfluramine use.

Not all the risk factors for primary pulmonary hypertension (PPH) are known. Appetite suppressants, including fenfluramine derivatives, are strongly suspected aetiological agents. In a 5 year retrospective study fenfluramine use was evaluated among patients referred to a medical centre specialising in the management of PPH. Fifteen (20%) of 73 patients with PPH had used fenfluramine: all of them were women and in 10 (67%) there was a close temporal relation between fenfluramine use and the development of exertional dyspnoea. Initial right heart catheterisation in the 15 women showed severe resting pulmonary hypertension (mean (SD)) with pulmonary artery pressure (PAP) 57 (9) mm Hg, cardiac index 2.1 (0.5) l/min/m2, and pulmonary vascular resistance (PVR) 29 (10) U/m2. Short-term epoprostenol infusion produced a significant vasodilator response in 10 patients (mean fall in PVR 24 (15%) compared with control values). Three fenfluramine users with PPH showed spontaneous clinical and haemodynamic improvement 3, 6 and 12 months after drug withdrawal but there was no significant difference in overall survival (transplant recipients excluded) between fenfluramine users and controls. Histological examination of lung tissue from five women who had used fenfluramine and 22 controls, with PPH showed features typical of advanced plexogenic pulmonary arteriopathy in all. These results do not accord with earlier reports that PPH associated with fenfluramine is less severe and has a better outcome. Fenfluramine may be one aetiological agent that can precipitate or hasten the development of PPH. The results of a European case-control study should give new insights into risk factors for PPH and the cause and effect relation with fenfluramine.     

Long-term use of sildenafil in inoperable chronic thromboembolic pulmonary hypertension

BACKGROUND: There are currently no licensed medical therapies for inoperable chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: In this double-blind, placebo-controlled pilot study, 19 subjects with inoperable CTEPH were randomly assigned to sildenafil or placebo for 12 weeks. The primary end point was change in 6-min walking distance (6MWD). Secondary end points included changes in World Health Organization (WHO) class, cardiopulmonary hemodynamics, quality of life (QOL) scores, and N-terminal pro brain natriuretic peptide (NT-proBNP). All subjects were transferred to open-label sildenafil at the end of the study and offered repeat assessment at 12 months. RESULTS: There were no significant differences between the two groups with respect to change in exercise capacity. However significant improvements were seen in WHO class and pulmonary vascular resistance (PVR). Seventeen subjects were eligible for reassessment at 12 months and demonstrated significant improvements in 6MWD, activity and symptom components of QOL, cardiac index, PVR, and NT-proBNP. CONCLUSIONS: Although this pilot study was insufficiently powered to test the primary end point, it did suggest beneficial effects in favor of sildenafil in several secondary end points at both 3 months and 12 months. Further larger-scale trials of sildenafil in inoperable CTEPH are required to confirm these findings and potentially increase the treatment options available for this devastating disease. TRIAL REGISTRATION: The study protocol was registered with the UK National Research Register database (publication ID N0542136603).     

Selective serotonin reuptake inhibitor use and outcomes in pulmonary arterial hypertension

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary vascular resistance which leads to right ventricular failure. Serotonin and the serotonin transporter play an important role in animal and human studies of PAH. We therefore hypothesized that PAH patients treated with high-affinity selective serotonin reuptake inhibitors (SSRIs) would have a reduced risk of death compared to PAH patients not treated with SSRIs. METHODS: We performed a retrospective cohort study of 84 consecutive adult PAH patients who underwent initial evaluation from January 1994 to June 2002 at the Pulmonary Hypertension Center of the New York Presbyterian Hospital. Patient-time while receiving high-affinity SSRIs (K(d)<1nmol) (paroxetine, sertraline, or fluoxetine) was considered "exposed". Patient-time while receiving tricyclic, atypical, or no antidepressants was considered "unexposed". RESULTS: Thirteen of the 84 patients (15%) used high-affinity SSRIs during the study period. Five patients were taking high-affinity SSRIs at baseline and 8 initiated high-affinity SSRIs during the follow-up period. The median time from baseline evaluation until initiation of high-affinity SSRIs was 125 (0-1227) days. The median duration of high-affinity SSRI use was 482 (110-1624) days and the total at-risk time on high-affinity SSRIs was 18.1 person-years. Seventy-nine (94%) patients were treated with warfarin; 38 (45%) received continuous intravenous epoprostenol; 12 (14%) received continuous subcutaneous treprostinil, and 23 (27%) were treated with oral bosentan. The median follow-up was 764 days. Twenty-four patients died and one underwent lung transplantation during the study period. There were no differences in age, gender, diagnosis, hemodynamics, or incidence of acute vasoreactivity between SSRI users and non-users. The risk of death for high-affinity SSRI users was lower but not statistically significantly different from that of non-users (hazard ratio=0.53, 95% CI 0.07 to 3.9, p=0.53). Adjustment for demographics, diagnosis, hemodynamics, or other therapies did not significantly change this result. CONCLUSIONS: SSRI use was associated with a 50% reduction in the risk of death in a cohort of PAH patients which was not statistically significant. Larger cohort studies may better define this relationship; an adequately powered trial of high-affinity SSRIs in PAH patients may be warranted.     

吸入一氧化氮治疗肺动脉高压的作用机理与应用评价

目的对吸入一氧化氮（NO）治疗肺动脉高压的临床药理学与临床毒理学进行评价。方法30例成人和54例儿童肺动脉高压患者吸人NO治疗。吸入前、吸入后30min和停吸后2h、24h分别取血浆测定NO代谢产物（NO_2~-）的浓度以及环磷酸鸟苷（cGMP）、丙二醛（MDA）和内皮素（ET-1）的水平，取循环白细胞测定一氧化氮合成酶（NOS）的活性。结果吸入NO后血中一氧化氮的浓度明显增加（P＜0．01），信息传递物质cGMP水平显著升高（P＜0．05），而脂质过氧化代谢产物MDA没有增多（p＞0．05），ET-1水平保持不变（P＞0．05），NOS活性不受影响（P＞0．05）。结论外源性NO亦通过cGMP发挥作用。当吸入浓度维持在一定范围内时，NO作为药物治疗是基本安全、有效的，因此NO是一种极具潜力的选择性肺动脉扩张剂。     

Chronic pulmonary embolism and pulmonary hypertension

Incomplete resolution of acute pulmonary embolism (PE) is frequently observed after acute PE and may rarely result in chronic thromboembolic pulmonary hypertension (CTEPH). The underlying pathophysiological mechanism is largely unknown. Evidence underlines the concept of a dual pulmonary vascular compartment model consisting of increased pulmonary vascular resistance by both large vessel obstruction and distal small vessel obliteration, the latter initiated by pathological vascular remodeling. Up to 40% of patients with established CTEPH have no prior history of symptomatic venous thromboembolism. CTEPH is associated with a poor prognosis if left untreated. Therefore, the diagnostic approach of CTEPH aims at assessing the location and extent of the embolic obstruction, establishing the operability and prognosis of the patients and ruling out other variations of pulmonary hypertension with distinct indicated treatment. Heart catheterization for invasive pressure measurements and pulmonary catheter angiography is obligatory for the final diagnosis. Pulmonary thromboendarterectomy is the treatment of choice. In certain patients with persistent or recurrent pulmonary hypertension after surgery or with inoperable disease, pharmacotherapy might be beneficial.     

Hyperthyroidism and pulmonary hypertension

In recent years, many authors have described several cases revealing an association between hyperthyroidism and pulmonary hypertension (PH). This observational study was designed to evaluate the incidence of PH in hyperthyroidism and was set in a department of internal medicine and pulmonary diseases with an out-patients department of endocrinology. Thirty-four patients, 25 women and nine men, with a mean age of 38 +/- 15 SD years participated. Twenty had Graves' disease and 14 had a nodular goitre. The patients were divided into two equally matched groups: those with a recently diagnosed hyperthyroidism, taking no drugs (group 1; n = 17) and those in a euthyroid state taking methimazole (group 2; n= 17). Transthoracic Doppler echocardiography was performed and systolic pulmonary artery pressurements of (PAPs) was determined by the tricuspid regurgitation method using the Bernoulli equation. Measurements of triiodothyronine, tetraiodothyronine, free thyroxine (Ft4), thyroid-stimulating hormone (TSH) and antithyroglobulin and antimicrosomal antibodies were also taken. We found a mild PH in seven patients of group 1 and in none of group 2.The mean +/- SD systolic pulmonaryartery pressurewas 28.88 +/- 6.41 in group 1 and 22.53 +/- 1.84 ingroup 2 (P<0.0001). A correlation was found between the TSH value and PAPs (r = -082;P < 0.001) and Ft4 and PAPs (r = 0 85; P < 0.001) in group 1. These findings indicate the presence of a frequent association between PH and hyperthyroidism. We suggest that hyperthyroidism be included in the differential diagnosis of PH.     

Bosentan use in systemic lupus erythematosus patients with pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) in patients with systemic lupus erythematosus (SLE) is uncommon but is associated with poor survival. This study aimed to examine the long-term effects of bosentan, a dual endothelin-1 receptor antagonist, on symptomatology, haemodynamics and quality of life measures in SLE patients with symptomatic PAH. Four local patients had been followed up prospectively with pre-defined protocol during 12-months of bosentan treatment. Six minute walk distance (6MWD), NYHA functional class, Borg Dyspnoea Index (BDI) and SF-36 were measured at 0, 3, 6, 9 and 12 months. Systolic pulmonary arterial pressure (PAP) was measured by transthoracic echocardiography at zero, six and 12 months. Clinical parameters were analysed, pooling data from other SLE patients reported in the literature (n = 4). Bosentan was found to result in significant improvement in 6MWD compared to baseline [+24.8 m, +26.2 m, +54 m and +62.7 m at three (P = 0.001), six (P = 0.001), nine (P = 0.24) and 12 (P = 0.01) months respectively]. A differential effect was found with greater response in patients with lower exercise capacity. This was accompanied by decrease in NYHA functional class, BDI, transient or sustained drop in systolic PAP and mild improvement in SF-36 domains including mental health, vitality, social function and general health. Significantly deranged liver function was found in one patient.