依洛前列环素吸入治疗对高原肺动脉高压患者血流动力学的影响

目的探讨吸入依洛前列环素对高原肺动脉高压（PAH）患者血流动力学的影响。方法12例重度PAH患者行吸入依洛前列环素治疗,观察吸入药物前后各血流动力学参数的变化。结果吸入依洛前列环素后PAH患者的肺动脉收缩压、肺动脉舒张压、肺动脉平均压、肺血管阻力下降,外周动脉血血氧饱和度、周围动脉氧分压、体循环血流量、肺循环血流量、心脏指数（C I）增加;肺小动脉嵌顿压、心率无明显变化。结论吸入依洛前列环素治疗PAH患者安全有效。     

肺心病患者吸入一氧化氮即刻血液动力学效应

目的：评价一氧化氮（ＮＯ）对肺心病肺动脉高压的急性治疗作用。方法：１３例（男９例，女４例）肺心病患者，平均年龄５２±１１岁（２１～５６岁）。检查前３天停服血管扩张药，在心导管检查时吸入ＮＯ（２０～８０ｐｐｍ）１０～１５分钟，吸入前后测右房压、肺动脉压同时取动脉及混合静脉血测血氧饱和度、血氧分压（ＰａＯ２）及混合静脉血氧饱和度（ＳｖＯ２）。结果：吸入ＮＯ后，肺动脉压下降，收缩压、舒张压及平均压分别下降３６．０％、３２．４％及２８．１％（Ｐ均＜０．００１）；肺血管阻力降低３８．５％（Ｐ＜０．０１）；肺动脉收缩压与体动脉收缩压比值从０．３９下降到０．２４，心脏指数增加１０．５％（Ｐ＜０．０１）；ＰａＯ２、ＳｖＯ２均值分别增加４．７％、８．７％（Ｐ均＜０．０５）。结论：吸入ＮＯ可使肺心病肺动脉高压患者肺血管扩张，降低肺动脉压及右室后负荷能预防或延缓心力衰竭的发生。     

高原地区先天性心脏病并发重度肺动脉高压的围术期管理

目的:探讨降低高原地区先天性心脏病并发肺动脉高压患者围术期并发症和手术死亡率的策略,评估吸入一氧化氮（NO)在先天性心脏病并发重度肺动脉高压患儿围术期的治疗效果。方法: 回顾性分析2009年6月~2012年12月我院收治的31例高原地区先天性心脏病并发重度肺动脉高压患者围术期管理经验,分析其术前、术中和术后等治疗因素对患者预后的影响,以及术后患者吸入NO 前后的心率、平均动脉压、中心静脉压、动态肺顺应性及氧合指数的变化。结果: 1例患者死亡,其余30 例患者在经过严格围术期管理及吸入NO 治疗后,心率、血压无明显改变,平均超声肺动脉压力、动态肺顺应性、氧合指数比治疗前明显改善,有统计学意义。结论: 严密的围术期管理及NO吸入治疗对治疗高原地区先天性心脏病并发重度肺动脉高压患者具有较好的临床效果。     

吸入一氧化氮在肺动脉栓塞术后肺动脉高压的临床应用

目的:评价吸入一氧化氮(nitric oxide,NO)对肺动脉栓塞外科手术治疗后肺动脉高压(pulmonary arterial hypertension,PH)患者的治疗作用。方法:回顾性分析安贞医院2005年1月1日至2011年8月1日,62例接受外科手术治疗的肺动脉栓塞患者临床资料,15例患者在肺动脉栓塞外科手术治疗后仍存在PH时,吸入NO浓度为(10～30)×10-6,记录NO吸入时间、吸入时呼吸功能指标和血流动力学参数。结果:术后平均吸入NO时间(46.3±6.4)h,动脉血氧饱和度(SaO2)、动脉血氧分压(PaO2)、动脉血氧分压与吸入氧浓度比值(PaO2/FiO2)较吸入前改善,平均肺动脉压(mPAP)较吸入前下降(P<0.05)。结论:对于肺动脉栓塞术后PH患者吸入NO,可以改善氧合并降低肺动脉压力。     

吸入一氧化氮对左向右分流型先心病合并重度肺动脉高压的肺血管平滑肌细胞凋亡调控的影响

目的研究拟用形态学方法TUNEL染色观察肺动脉增生组的肺小动脉平滑肌细胞的凋亡情况和分子生物学的方法DNALadder及PCR反转录反应研究肺血管平滑肌细胞凋亡基因Bcl-2和基因Bax表达,以探讨NO是否可以通过调控凋亡相关基因表达来调控肺血管平滑肌细胞凋亡这一途径,实现对先心病肺动脉高压的治疗以及开发术前治疗肺动脉高压新方法具有重要意义。方法于2001年3月—7月共选择先心病患儿15例,分为4组。男10例,女5例,年龄小于5岁,0.5～5(2.9±1.5)岁。组1为肺动脉平滑肌增生吸入NO治疗组共6例,包括室间隔缺损2例和完全心内膜垫4例均合并重度肺动脉高压每日吸入5～10ppmNO2—4h,约10～14d;组2为肺动脉平滑肌增生对照组,不吸入NO治疗共3例,包括室间隔缺损2例和完全心内膜垫1例均合并重度肺动脉高压;组3为正常肺动脉对照组共3例,包括3例房间隔缺损合并轻度肺动脉瓣狭窄;组4为肺动脉发育不良对照组共3例,均为法鲁氏四联症。于术中,体外循环后取右肺中叶肺组织1×1cm3分别行TUNEL染色和DNALadder及PCR实验测定Bcl-2基因和Bax基因表达。结果形态学TUNEL染色方法显示左向右分流型先心病合并重度肺动脉高压,吸入NO治疗组与正常肺动脉组比较,肺小动脉平滑肌细胞凋亡增多;而未吸入NO对照组与正常肺动脉组比较则反之,肺小动脉平滑肌细胞凋亡细胞极少。ASD+轻度PS、TOF和VSD+PH吸入NO治疗的基因Bax表达上调。左向右分流型先心病合并重度肺动脉高压未吸入NO对照组的肺血管平滑肌细胞凋亡基因Bcl-2表达上调,Bax基因表达下调;吸入NO治疗组的肺血管平滑肌细胞凋亡基因Bax表达上调,Bcl-2表达下调。结论比两组肺动脉增生组的患者,NO对肺动脉高压的治疗主要是通过对细胞凋亡基因表达的调控而达到治疗目的。     

外源性一氧化氮吸入治疗肺动脉高压的实验研究

目的 :探讨吸入一氧化氮 (NO)对肺动脉高压动物的肺、体循环压力及肺血管结构重组逆转的影响。　　方法 :实验组 6只 ,对照组 4只。实验组的 6只高动力型肺动脉高压模型犬 ,采用面罩法间断吸入 NO[4 0 ppm(1ppm=1/ 10 6 ) ]1周。观察吸入 NO后肺动脉平均压、体动脉平均压和肺血管阻力及动脉血气变化 ;图像分析法测定肺小血管中膜厚度 ;监测外周血高铁血红蛋白含量。　　结果 :吸入 NO后肺动脉平均压、肺血管阻力明显降低 (P<0 .0 1) ,而体动脉压无变化 ,氧分压升高 ,二氧化碳分压降低。吸入 NO前后肺小血管中膜厚度无明显变化 (P>0 .0 5 )。高铁血红蛋白均低于正常值 15 g/ L。　　结论 :吸入 NO能选择性降低肺动脉压而不影响体动脉压 ,明显改善氧合 ,但对肺血管病理学改变无明显影响 ;吸入NO(40 ppm) 1周未见有明显蓄积毒性作用。     

西地那非与前列腺素E1治疗猪肺动脉高压

目的 比较西地那非和前列腺素E1对幼猪肺动脉高压模型的影响.方法 体质量约5 kg实验用健康幼猪24只,用经气管内吸入胎粪法诱发幼猪产生肺动脉高压,2 h后建立急性缺氧性肺动脉高压模型.随机将幼猪分成4组:对照组,不给予任何药物治疗:西地那非组,静脉注射枸橼酸西地那非(2 mg/kg)、前列腺素E1组,持续静脉滴注前列腺素E120 ng/(kg·rain)至实验结束;合用组同时给予西地那非组和前列腺素E1.结果 吸入胎粪2 h后,记录动物的肺动脉压、肺血管阻力(pulmonary vascular resistance,PVR)和体循环血管阻力(systemic vascular resistance,SVR).发现肺动脉压、PVR和PVR/SVR均随时间明显增加.施加药物干预以后,西地那非组与合用组的上述指标均明显迅速下降,并且心输出量和心脏指数明显提高;前列腺素E1组肺动脉压、PVR以及PVR/SVR下降程度不如西地那非组明显,心输出量、心脏指数无改善:对照组的肺动脉压、PVR以及PVR/SVR无下降.结论 西地那非降低肺动脉压和肺血管阻力,改善心功能,同时对体循环血流动力学无不良影响;在本实验用量,西地那非扩张肺血管和降低肺血管阻力的作用比前列腺素E1强;两者联合应用没有发生协同降低肺动脉压作用.     

西地那非与前列腺素E1治疗猪肺动脉高压

目的 比较西地那非和前列腺素E1对幼猪肺动脉高压模型的影响。方法 体质量约5kg实验用健康幼猪24只，用经气管内吸入胎粪法诱发幼猪产生肺动脉高压，2h后建立急性缺氧性肺动脉高压模型。随机将幼猪分成4组：对照组，不给予任何药物治疗;西地那非组，静脉注射枸橼酸西地那非（2mg/kg）、前列腺素E1组，持续静脉滴注前列腺素E120ng/（kg·min）至实验结束;合用组同时给予西地那非组和前列腺素E1。结果 吸入胎粪2h后，记录动物的肺动脉压、肺血管阻力（pulmonary vascular resistance，PVR）和体循环血管阻力（systemic vascular resistance，SVR）。发现肺动脉压、PVR和PVR/SVR均随时间明显增加。施加药物干预以后，西地那非组与合用组的上述指标均明显迅速下降，并且心输出量和心脏指数明显提高;前列腺素E1组肺动脉压、PVR以及PVR/SVR下降程度不如西地那非组明显，心输出量、心脏指数无改善;对照组的肺动脉压、PVR以及PVR/SVR无下降。结论 西地那非降低肺动脉压和肺血管阻力，改善心功能，同时对体循环血流动力学无不良影响;在本实验用量，西地那非扩张肺血管和降低肺血管阻力的作用比前列腺素E1强;两者联合应用没有发生协同降低肺动脉压作用。     

吸入低浓度一氧化氮在风湿性心脏病合并肺动脉高压患者术中应用的研究

目的 :对风湿性心脏病 (风心病 )二尖瓣狭窄合并肺动脉高压患者 ,观察术前和术后吸入 40 ppm一氧化氮 (NO)其血液动力学效应 ,以及体外循环对其效应的影响。　　方法 :选择 15例风心病合并肺动脉高压行择期瓣膜置换术的患者 ,在体外循环前、后吸入 40 ppm NO气体。　　结果 :术前肺血管阻力 (PVR)为 2 0～ 135 k Pa·s/ L,肺动脉压为 2 8/ 17～ 87/ 45 mm Hg(1mm Hg=0 .133k Pa)。吸入 40 ppm NO后肺动脉收缩压、肺动脉舒张压、肺动脉平均压及 PVR在体外循环前、后均明显降低 (P均 <0 .0 0 1)。在体外循环前、后肺血管阻力差值 (△ PVR) / PVR分别为 (5 3.2± 18.5 ) % (P<0 .0 0 1)和 (2 2 .7± 2 2 .2 ) % (P<0 .0 1) ,体外循环前、后两者差异极显著 (P<0 .0 0 1)。吸入 NO治疗前、后肺毛细血管楔压均无明显改变 (P>0 .0 5 ) ,而心排血量均明显增加 (P<0 .0 1)。　　结论 :风心病合并肺动脉高压患者吸入 40 ppm NO,可选择性地扩张肺动脉 ,体外循环可明显减弱其效应。     

吸入小剂量一氧化氮对肺纤维化患者的影响

特发性肺间质纤维化(IPE)足以肺的进行性炎症和纤维化过程为其特征的疾病。已证明IPE患者长期吸氧治疗无效,甚至发生低氧血症和肺动脉高压。吸入一氧化氮(NO)对各种原因导致的肺动脉高压有显著选择性肺动脉扩张作用。慢性肺动脉高压患者吸入NO比氧(O_2)更能有效降低平均肺动脉压。然而,吸入     

前列地尔联合西地那非治疗心脏围手术期肺动脉高压的疗效观察

目的观察前列地尔联合西地那非,两药物联合应用治疗围手术期肺动脉高压的可行性。方法收集2012年1月至2013年1月我科收治的心脏手术合并肺动脉高压患者80例,其中先天性心脏病40例,后天性心脏瓣膜病40例,并由此分为先心组和瓣膜组,两组再随机分为实验组和对照组。对照组40例围手术期给予吸氧、强心、利尿、扩管、改善心肌重构等常规治疗,实验组在对照组治疗基础上联合前列地尔、西地那非治疗。术前和术后第7~8天分别进行超声心动图检查、动脉血气分析,比较两组疗效差异。结果四组患者手术后肺动脉内径、肺动脉收缩压、左室射血分数、动脉血氧分压指标均有明显改善(P0.05),两大组中,实验组较对照组改善均更为显著(P0.05)。结论对于先天性心脏病或心脏瓣膜病需行心脏外科手术治疗的肺动脉高压患者,心脏手术可明显降低肺动脉压,改善心功能;在心脏围手术期联合应用前列地尔和西地那非,两药协同,可进一步改善肺动脉高压,减轻肺动脉高压患者的症状,改善其预后。     

Successful treatment with sildenafil in systemic sclerosis patients with isolated pulmonary arterial hypertension: two case reports

We describe two systemic sclerosis (SSc) patients with isolated pulmonary arterial hypertension (PAH) who were given treatment with 50 mg oral sildenafil per day. We evaluated the efficacy of oral sildenafil for isolated PAH in SSc patients by direct assessment with cardiac catheterization before and 6 months after the initiation of sildenafil. Right-heart catheterization demonstrated decreased mean pulmonary artery pressure, decreased pulmonary vascular resistance, and increased cardiac output after treatment with sildenafil. Brain natriuretic peptide levels were gradually decreased. The 6-min walking distance was greatly extended. Moreover, the physical conditions of both patients were much improved. We recognized no adverse events. We propose that oral sildenafil may be beneficial as a selective pulmonary vasodilator and as long-term treatment in SSc patients with isolated PAH.     

Sildenafil therapy for pulmonary hypertension before and after pediatric congenital heart surgery

Pulmonary hypertension associated with pediatric congenital heart defects is a major cause of postoperative morbidity and death. Sildenafil has been combined with inhaled nitric oxide to treat pulmonary hypertension. We retrospectively studied the pre- and postoperative effects of oral sildenafil as monotherapy in children with pulmonary hypertension who underwent surgery to correct congenital cardiac defects. From September 2005 through November 2009, 38 children with moderate-to-severe pulmonary arterial hypertension (pulmonary arterial/aortic pressure ratio, >0.7) underwent cardiac surgery at our institution. Fifteen patients were given sildenafil (0.35 mg/kg, every 4 hr) orally or through nasogastric tubes 1 week before and 1 week after surgery. Twenty-three patients of comparable medical status were given sildenafil only upon the institution of cardiopulmonary bypass and for 1 week after surgery. Postoperatively, the 15 patients who were given preoperative sildenafil had significantly lower mean pulmonary arterial pressures (25.6 ± 3.1 vs. 30.4 ± 5.7 mmHg; P = 0.005) and pulmonary arterial/aortic pressure ratios (0.35 ± 0.05 vs. 0.42 ± 0.07; P = 0.002) than did the other 23 patients. The preoperative therapy also shortened cardiopulmonary bypass time, mechanical ventilation time, and lengths of intensive care unit and hospital stays. No sildenafil-related hypertensive crises or sequelae occurred. As monotherapy, oral sildenafil in low doses appears to control pulmonary hypertension safely and effectively in children undergoing operations to correct congenital heart defects, particularly when it is given both preoperatively and postoperatively. Further study is warranted.     

Beneficial effect of sildenafil following surgery for mitral stenosis complicated by pre-capillary pulmonary hypertension: report of two cases

Pulmonary hypertension is a serious disorder, difficult to treat especially in the severe forms. The treatment consists mainly of calcium channel blockers, anti-coagulation, intravenous epoprostenol, inhaled nitric oxide and recent agents as bosentan and sildenafil. Sildenafil, a phosphodiesterase 5 specific inhibitor, has been largely evaluated in primary pulmonary hypertension, and in some cases of secondary pulmonary hypertension including parenchymal and thromboembolic diseases; it has not yet been evaluated in severe pulmonary hypertension with elevated pre-capillary resistance in operated mitral stenosis. We report the cases of two patients operated from mitral valve replacement for severe mitral stenosis with elevated pre-capillary resistance, where oral sildenafil, introduced empirically immediately after the surgical procedure at the dose of 50 mg/d, permitted a significant decrease in pulmonary pressures and resistances, allowing a rapid withdrawal of nitric oxide and reducing therefore hospitalization time in the intensive care unit. We think that this simple treatment, with or without association to nitric oxide, should be generalized to persistent pulmonary hypertension following cardiac surgery.     

PGE1治疗鱼精蛋白中和肝素诱发肺动脉高压的疗效观察

本研究的目的观察PGE1对鱼精蛋白中和肝素所致肺动脉高压的治疗作用.7例体外循环心内直视手术患者,心内操作结束主动脉根部注射鱼精蛋白对抗肝素后肺动脉平均压≥30mmHg即行PGE1 0.02～0.04蘥*min-1*Kg-1持续输注,并于注射前后不同时间分别监测动脉收缩压(SABP)、舒张压(DABP)、平均动脉压(MABP)、中心静脉压(CVP)、平均肺动脉压(MPAP)、肺毛细血管嵌压(PCWP),采用热稀释法测定心输出量(CO),并计算心指数(CI)、每搏指数(SI)、左心室和右心室做功指数(LVSWI,RVSWI)、肺循环阻力(PVR)及体循环阻力(SVR).结果:PGE1持续输注后,SABP、DABP、CVP、CO、SI未发生变化.肺动脉压、右室做功指数和肺血管阻力在持续PGE1 0.02～0.04μg*min-1*Kg-1注射后30min降低为注射前水平(P＜0.05).结论:持续静脉输注PGE1 0.02～0.04μg*min-1*Kg-1可以逆转体外循环心内直视手术鱼精蛋白中和肝素所致的肺动脉高压,降低肺血管阻力,对动脉压和心排血量无明显影响.     

Hemodynamic effects of sildenafil in patients with congestive heart failure and pulmonary hypertension: combined administration with inhaled nitric oxide

STUDY OBJECTIVES: In patients with pulmonary hypertension (PH) secondary to congestive heart failure, inhaled nitric oxide (NO) increases pulmonary vascular smooth-muscle intracellular cyclic guanosine monophosphate (cGMP) concentration, thereby decreasing pulmonary vascular resistance (PVR) and increasing cardiac index (CI). However, these beneficial effects of inhaled NO are limited in magnitude and duration, at least in part due to cGMP hydrolysis by the type 5 isoform of phosphodiesterase (PDE5). The goal of this study was to determine the acute pulmonary and systemic hemodynamic effects of the selective PDE5 inhibitor, sildenafil, administered alone or in combination with inhaled NO in patients with congestive heart failure and PH. DESIGN: Single center, case series, pharmacohemodynamic study. SETTING: Cardiac catheterization laboratory of a tertiary care academic teaching hospital. PATIENTS: We studied 11 patients with left ventricular systolic dysfunction due to coronary artery disease or idiopathic dilated cardiomyopathy who had PH. INTERVENTIONS: We administered oral sildenafil (50 mg), inhaled NO (80 ppm), and the combination of sildenafil and inhaled NO during right-heart and micromanometer left-heart catheterization. MEASUREMENTS AND RESULTS: Sildenafil administered alone decreased mean pulmonary artery pressure by 12 +/- 5%, PVR by 12 +/- 5%, systemic vascular resistance (SVR) by 13 +/- 6%, and pulmonary capillary wedge pressure by 12 +/- 7%, and increased CI by 14 +/- 5% (all p < 0.05) [+/- SEM]. The combination of inhaled NO and sildenafil decreased PVR by 50 +/- 4%, decreased SVR by 24 +/- 3%, and increased CI by 30 +/- 4% (all p < 0.01). These effects were greater than those observed with either agent alone (p < 0.05). In addition, sildenafil prolonged the pulmonary vasodilator effect of inhaled NO. Administration of sildenafil alone or in combination with inhaled NO did not change systemic arterial pressure or indexes of myocardial systolic or diastolic function. CONCLUSIONS: PDE5 inhibition with sildenafil improves cardiac output by balanced pulmonary and systemic vasodilation, and augments and prolongs the hemodynamic effects of inhaled NO in patients with chronic congestive heart failure and PH.     

Clinical efficacy of sildenafil in primary pulmonary hypertension: a randomized, placebo-controlled, double-blind, crossover study

OBJECTIVES: In a randomized, double-blind, crossover design, we compared the efficacy of sildenafil with placebo in patients with primary pulmonary hypertension (PPH). The primary end point was the change in exercise time on treadmill using the Naughton protocol. Secondary end points were change in cardiac index and pulmonary artery systolic pressure as assessed by Doppler echocardiography and quality of life (QOL) as assessed by a questionnaire. BACKGROUND: Primary pulmonary hypertension is a disorder with limited treatment options. Uncontrolled studies had shown sildenafil to be beneficial in the treatment of PPH. METHODS: After initial clinical evaluation, including Doppler echocardiography and treadmill exercise test, patients were randomized to placebo or sildenafil with dosages ranging from 25 to 100 mg thrice daily on the basis of body weight. The evaluation was repeated after six weeks. Then patients were crossed over to alternate therapy. Final evaluation was performed after another six weeks of treatment. RESULTS: Twenty-two patients completed the study. Exercise time increased by 44% from 475 +/- 168 s at the end of placebo phase to 686 +/- 224 s at the end of sildenafil phase (p < 0.0001). With sildenafil, cardiac index improved from 2.80 +/- 0.9 l/m2 to 3.45 +/- 1.1 l/m(2) (p < 0.0001), whereas pulmonary artery systolic pressure decreased insignificantly from 105.23 +/- 17.82 mm Hg to 98.50 +/- 24.38 mm Hg. There was significant improvement in the dyspnea and fatigue components of the QOL questionnaire. During the placebo phase, one patient died and another had syncope. There were no serious side effects with sildenafil. CONCLUSIONS: Sildenafil significantly improves exercise tolerance, cardiac index, and QOL in patients with PPH.     

A study of clinical efficacy of sildenafil in patients with primary pulmonary hypertension

BACKGROUND: Primary pulmonary hypertension is a disorder with limited treatment options and poor outcome. Sildenafil, a pulmonary vasodilator, is likely to be beneficial in primary pulmonary hypertension. We studied the clinical efficacy of sildenafil in patients with primary pulmonary hypertension. METHODS AND RESULTS: A registry of patients with primary pulmonary hypertension has been maintained in our hospital since January 1999. Of a total of 60 patients. 29 (M:16, F:13) consented to try sildenafiL. New York Heart Association functional class, six-minute walk test and Doppler echocardiographic evaluation of pulmonary artery pressure was done before and after treatment with sildenafil. Sildenafil was initiated at a dose of 25 mg thrice a day and increased up to 100 mg thrice a day as tolerated. There was a significant improvement in the functional class. The six-minute walked distance increased from 297.07+/-130.69 m at baseline to 427.68+/-85.35 m after 3 months of sildenafil therapy (p<0.0003). The mean of the pulmonary artery systolic pressure before starting sildenaffil was 109.26+/-24.15 mmHg (mean+/-SD) and it decreased to 95.15+/-24.64 mmHg (p<0.008). While 19 of the 31 historical controls in whom sildenafil was not given died during follow-up (11-44 months), only 1 of the 29 patients given sildenafil died (in an accident) during follow-up (5-20 months). CONCLUSIONS: Sildenafil, a pulmonary vasodilator, has a beneficial effect in patients with primary pulmonary hypertension in improving the functional class, six-minute walked distance and in decreasing the pulmonary artery pressures.     

Decrease in pulmonary artery pressure with slow release nifedipine in Saudi patients with primary pulmonary hypertension

We studied the acute and short-term hemodynamic effects of vasodilators in three Saudi patients with primary pulmonary hypertension. The study protocol included the measurement of pulmonary artery pressure, resistance and cardiac output at baseline and at 15, 30, 45 and 60 minutes after 10 mg sublingual nifedipine. These hemodynamic studies repeated at 3 and 6 months follow-up. A 24 hour profile of pulmonary artery and aortic pressures were recorded to evaluate the effect of 20 mg of slow release nifedipine, after 25 mg of captopril and 5 mg of sublingual isordil. After nifedipine there was a marked reduction in systolic pulmonary artery pressure from 85 +/- 18 to 55 +/- 8 mmHg and the pulmonary resistance decreased from 1422 +/- 367 to 954 +/- 69 dynes-sec/cm-5. The cardiac output increased from 2.9 +/- 0.2 to 0.2 to 4.0 +/- 0.4 l/min after nifedipine. The patients were discharged on nifedipine 10 mg qid, except for patient #3 who was a non-responder. At follow-up there was a symptomatic improvement and a favourable hemodynamic response was maintained, though patient #2 required a higher dose of nifedipine. The pulmonary artery 24 hour pressure profile revealed that 20 mg slow release adalat reduced pulmonary artery pressure for a 6 hour period. Whereas, regular nifedipine decreased pulmonary artery pressure for a period of less than 90 minutes. There was no favourable hemodynamic response to either captopril 25 mg oral of isordil 5 mg administered sublingually. We conclude that slow release nifedipine decreases the pulmonary artery pressure for longer periods compared to regular nifedipine in patients with primary pulmonary hypertension.