体外循环对先天性心脏病合并肺动脉高压患者血浆一氧化氮、内皮素、肾上腺髓质素水平的影响

目的 探讨体外循环（CPB）对先天性心脏病合并肺动脉高压患者血浆一氧化氮（NO）、内皮素（ET）、肾上腺髓质素（ADM）水平的影响。方法 选择先天性心脏病拟在CPB下行心脏畸形矫正术患者36例,根据术前肺动脉收缩压（PASP）分为Ⅰ组（PASP＜30 mm Hg,n=8）、Ⅱ组（PASP 30～50 mm Hg,n=15）和Ⅲ组（PASP＞50 mm Hg,n=13）。分别于麻醉诱导前（基础值）、CPB即刻、CPB结束、CPB后3h、6h和24h采集桡动脉血,测定血浆NO、ET、ADM浓度。结果 Ⅱ组、Ⅲ组麻醉诱导前血浆ADM、ET、NO浓度高于Ⅰ组,其中ADM浓度随PASP的增高而升高（P＜0．05）,两者呈正相关（r= 0．858,P＜0．01）;与基础值相比,3组CPB后血浆ADM和ET浓度均增加,Ⅱ组、Ⅲ组CPB后NO浓度下降（P＜0．05）,Ⅰ组NO浓度变化无统计学意义（P＞0．05）。结论 ADM水平随PASP的增高而升高;CPB可引起先天性心脏病合并肺动脉高压患者血浆ET、ADM水平增高,NO水平降低。     

Pulmonary vascular resistance in children with congenital heart disease

Pulmonary and systemic blood flow and pulmonary vascular resistance were measured in 21 children with congenital heart disease. Blood flow was calculated by the direct Fick method, using measurements of metabolic gas exchange obtained by remote respiratory mass spectrometry. The observations showed that the administration of oxygen caused an appreciable fall in pulmonary vascular resistance in 16 of the 21 children studied and that this fall would not have been appreciated from a study of pulmonary arterial pressure alone as it was masked by a corresponding rise in blood flow. In 10 of 14 children, in whom superior vena caval blood was also sampled, the rise in flow was largely due to an increase in intracardiac left to right shunt. It was accompanied by widening of the alveolar-arterial oxygen gradient, perhaps due to imperfect gas equilibration within the lung.     

静脉麻醉药对先心病合并肺动脉高压病人肺循环阻力的影响

目的 探讨硫喷妥钠、异丙酚、氯胺酮用于先心病合并肺动脉高压病人麻醉诱导的可行性。方法 18例先心病合并肺动脉高压病人随机分成三组，分别应用硫喷妥钠2mg/kg、氯胺酮1mg/kg、异丙酚1mg/kg、直接注入肺动脉；测定用药前、用药后1min、5min的肺血管阻力。结果 用药后三组病人肺循环阻力的变化均无统计学意义；硫喷妥钠、异丙酚组体动脉压显著下降。结论 硫喷妥钠、氯胺酮、异丙酚用于先心病合并肺动脉高压病人的麻醉诱导是安全的。     

Urapidil reduces elevated pulmonary vascular resistance in patients before heart transplantation.

BACKGROUND: Elevated pulmonary vascular resistance is a major limitation for heart transplantation. Urapidil is a centrally and peripherally acting anti-hypertensive drug, able to decrease elevated pulmonary vascular resistance in patients with either chronic obstructive pulmonary disease or heart failure. Urapidil is available as an oral or intravenous drug. In this study, we evaluated the possible beneficial effects of intravenous urapidil in patients with reversible, elevated pulmonary vascular resistance who were scheduled for heart transplantation. METHODS: After approval by the Ethics Committee and written consent, 22 consecutive patients with end-stage heart failure and history of pulmonary vascular resistance >3 Wood units were enrolled into an open, prospective study. Using a (right ventricular ejection fraction) REF-Swan-Ganz catheter, hemodynamics were determined during administration of nitric oxide, and before and after 3 repeated intravenous applications of 10 mg urapidil. The treatment goal was reduction of pulmonary vascular resistance by at least 30%. RESULTS: Twenty-two patients were included to obtain complete data for 14 patients. Eight patients were not treated with urapidil: 7 patients had normal pulmonary vascular resistance at baseline, and 1 patient experienced moderate pulmonary edema before the study began. Two patients did not reach the treatment goal. In patients who responded to urapidil, the following hemodynamic changes were observed: decreased pulmonary vascular resistance (-48%), decreased transpulmonary gradient (20.0 to 13.7 mm Hg), decreased mean pulmonary arterial pressure (40 to 31 mm Hg), decreased systemic vascular resistance (-27%), mean arterial pressure (80 to 72 mm Hg), and increased right heart ejection fraction (21% to 27%). Heart rate remained unchanged. CONCLUSIONS: Intravenous urapidil lowered elevated pulmonary vascular resistance in patients before heart transplantation. In comparison with other vasodilative drugs, the major benefit of urapidil is its oral formulation.     

Evidence of pulmonary vascular disease after heart transplantation for Fontan circulation failure

OBJECTIVES: Elevated pulmonary vascular resistance may contribute to late Fontan circulation failure but is difficult to assess in such patients. Our aims were to assess outcomes of patients with failed Fontan circulation after heart transplantation and to determine whether elevated pulmonary vascular resistance might have contributed to the failure. METHODS: Fifteen patients (14 Fontan circulations, 1 Kawashima circulation) underwent transplantation. The most common indication was ventricular dysfunction (mean ventricular end-diastolic pressure 12.5 mm Hg). Patients with early failures (n = 4) required transplantation less than 1 year after the Fontan operation. Those with late failures (n = 11) underwent transplantation at least 1 year after the Fontan operation. Mean age at transplantation was 11.6 years. Mean Fontan-transplantation interval was 7.4 years. Mean pulmonary arterial pressure, transpulmonary gradient, and pulmonary vascular resistance before and after transplantation were assessed. Paired t tests of variable differences were used to compare variables. Survival was estimated by the Kaplan-Meier method. RESULTS: In-hospital mortality was 7%. There were 2 late events (1 death, 1 retransplantation) related to compliance or rejection issues. Graft survivals were 93%, 82%, and 82% at 3, 5, and 7 years, respectively. Posttransplantation pulmonary vascular resistance was elevated (>2.0 Wood units . m 2 ) in 11 of 14 survivors past initial hospitalization (mean 3.3 +/- 1.7 Wood units . m 2 ). Only patients with early Fontan failures (3 of 4) had normal posttransplantation pulmonary vascular resistance. In paired comparisons, posttransplantation transpulmonary gradient was increased by a mean of 6.8 mm Hg ( P < .0001) relative to pretransplantation value. CONCLUSIONS: Outcomes after heart transplantation for failed Fontan circulation were good. Mild-to-moderate pulmonary vascular disease was evident after heart transplantation for late failure. Elevated pulmonary vascular resistance is a likely contributor to Fontan circulation failure.     

The pathophysiology of pulmonary hypertension in congenital heart disease

Congenital heart disease with increased pulmonary blood flow commonly leads to the development of pulmonary hypertension and increased vascular reactivity. These serious sequelae are associated with the following two major categories of congenital heart defects: those resulting in increased pulmonary blood flow and increased pulmonary arterial pressure and those resulting in increased pulmonary venous pressure. Recent evidence that the pulmonary vascular endothelium is an important determinant of vascular tone has led to the hypothesis that endothelial injury, secondary to congenital heart disease with increased pulmonary blood flow, disrupts these regulatory mechanisms and thereby plays a role in the development of pulmonary hypertension and its associated increased vascular reactivity. In many animal models, endothelial dysfunction is a precursor for smooth muscle dysfunction, and there is an apparent progression from endothelial dysfunction to smooth muscle dysfunction as vascular changes progress. We established a chronic model of pulmonary hypertension with increased pulmonary blood flow in young lambs by placing a systemic-to-pulmonary shunt in utero. In this model, we found significant physiologic and molecular alternations of both the nitric oxide (NO) and endothelin signaling pathways, two important mechanisms by which the endothelium regulates pulmonary vascular tone. These alterations occur extremely early and precede severe anatomic changes. Early endothelial damage may contribute to the development of pulmonary hypertension and its associated enhanced pulmonary vascular reactivity.     

Early initiation of peritoneal dialysis after surgical repair of congenital heart disease

The mortality rate of infants who require renal replacement therapy after surgical repair of congenital heart disease has been reported to be 30%–79%. We report our experience with early initiation of continuous manual peritoneal dialysis (CPD) to treat fluid overload in 20 consecutive critically ill children who underwent CPD post cardiotomy. CPD catheters were inserted at the discretion of the cardiothoracic surgeon. CPD was started for evidence of total body fluid overload with inadequate urine output, and stopped when negative fluid balance was achieved and urine output improved. Median age was 10 days (range 3–186 days), mean time to start CPD post-operatively was 22 h (range 5–40 h), and mean duration of CPD was 50 h (range 13–92 h). CPD resulted in mean ultrafiltration of 93 ml/kg per day (range 43–233 ml/kg per day). Net negative fluid balance was 106 ml/kg per day (range 49–273 ml/kg per day). During CPD, the mean number of inotropes decreased from 2.2 to 1.6 (P<0.05) and urine output increased from 2.2 to 3.9 ml/kg per hour (P<0.01). No patient died during CPD or had CPD discontinued due to adverse hemodynamic effects. The overall mortality rate was 20%. We conclude that early initiation of CPD can safely and effectively promote fluid removal in infants after repair of congenital heart disease, with a lower mortality rate than has previously been reported. Received: 26 August 1998 / Revised: 21 December 1998 / Accepted: 5 January 1999     

先天性心脏病介入治疗后封堵器移位的急诊外科治疗

目的 探讨先天性心脏病（先心病）介入治疗后封堵器移位的原因以及急诊外科治疗的必要性和方法。方法 5例先心病病儿在接受介入治疗术后的数分钟到数天内封堵器部分移位或完全脱落，其中2例动脉导管未闭病儿封堵器分别脱落至左、右肺动脉开口处，2例房间隔缺损病儿封堵器部分移位造成残余分流，1例室间隔缺损病儿封堵器部分移位，封堵器尖端将三尖瓣前瓣腱索割断造成三尖瓣中到重度反流。5例在封堵器移位当日到1个月内在体外循环下急诊行封堵器取出术和先心病纠治术。结果 手术效果满意，5例病儿均未出现重要脏器功能损害，心功能恢复至Ⅰ级。结论 封堵器移位是先心病介入治疗后较严重的并发症；为防止和避免封堵器移位应严格掌握介入治疗术的指征和选择尺寸合适的封堵器；介入治疗术后早期应加强各项心脏专科检查和监测，一旦发现封堵器移位应紧急手术以避免病情恶化；只要处理及时，手术效果满意，心功能恢复良好。     

先天性心脏病合并肺动脉高压的手术治疗策略

先天性心脏病患者有很多由于合并心内左向右的分流,可能继发肺动脉高压,严重者可能发展为艾森曼格综合征,以至于使患者失去手术和治疗的机会.有些患者即使做了手术,手术后的低心排血量和呼吸功能衰竭等并发症会明显增加,手术病死率较高,远期疗效也不理想.因此,选择适当的时机对患者进行尽早的手术对降低手术病死率及提高手术疗效是十分重要的.对一些已经错过最佳手术时机的患者,如能够正确处理也可以提高手术的成功率,减少术后并发症.     

Noninvasive assessment of pulmonary vascular resistance and pressure in patients with congenital heart disease: a new method using M-mode echocardiography

Background  

The accurate evaluation of pulmonary vascular resistance (PVR) and mean pulmonary artery pressure is important to determine the optimal management and therapeutic strategy for patients with congenital heart disease (CHD). We evaluated the PVR and mean pulmonary artery pressure in 46 patients with several CHD types using the interventricular septum (IVS) motion determined by M-mode echocardiography.