The effects of pre-operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery

BACKGROUND: The aim of this study was to investigate the effects of pre-operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery. METHODS: Patients were randomly divided into placebo (group P, n= 16) and dexmedetomidine (group D, n= 16) groups. In group D, a 1 microg/kg bolus dose of dexmedetomidine was administered 10 min before the induction of anesthesia, followed by a 0.4 microg/kg/h infusion until the surgical incision. Anesthesia was induced with lidocaine (1 mg/kg), midazolam (0.2 mg/kg) and fentanyl (5 microg/kg) in both groups. Anesthesia was maintained with 0.5% isoflurane and fentanyl depending on the hemodynamic situation. The hemodynamic values during the investigation were obtained. RESULTS: In group D, the mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) were decreased effectively in comparison with the values in the placebo group (P < 0.05), and there was an attenuation in the increase in the systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) at the post-sternotomy period. CONCLUSIONS: The pre-operative administration of the alpha(2)-agonist dexmedetomidine decreases the fentanyl requirement and attenuates the increase in SVRI and PVRI at the post-sternotomy period relative to the baseline levels, and decreases effectively MAP, MPAP and PCWP in comparison with the values in the placebo group, in patients with pulmonary hypertension undergoing mitral valve replacement surgery.     

A comparison of the acute hemodynamic effects of inhaled nitroglycerin and iloprost in patients with pulmonary hypertension undergoing mitral valve surgery.

BACKGROUND: Since the presence of pulmonary hypertension (PHT) affects the prognosis of the patients, it is important to manage and evaluate PHT. The aim of this study was to compare the hemodynamic effects of inhaled nitroglycerin and iloprost during early postoperative period, in patients with PHT undergoing mitral valve replacement surgery. MATERIALS AND METHODS: One hundred patients with PHT (mean pulmonary artery pressure (MPAP) >25 mmHg at rest), were randomized to receive either inhalation of nitroglycerin (group I; n=50) or iloprost (group II; n=50) in the postoperative period. In both groups, baseline hemodynamic parameters were recorded before the treatment (T(0)). Then, patients in group I received 20 microg.kg(-1) nitroglycerin and those in group II received 2.5 microg.kg(-1) iloprost. The same parameters were recorded immediately after the end of the treatment (T(1)). RESULTS: In both study groups MPAP and pulmonary vascular resistance (PVR) were found to be significantly lower at T(1) when compared to that of T(0) period (p<0.05). MPAP and PVR were significantly lower and mean arterial pressure (MAP) was significantly higher in group II when compared to group I at T(1) period (p<0.05). In addition to decreases in PVR and MPAP, iloprost also increased cardiac output (CO)(4.9+/-1.3 vs 5.1+/-0.9, p<0.05) and stroke volume (SV)(48+/-13 vs 56+/-13, p<0.05). CONCLUSION: Inhaled iloprost and nitroglycerin, both effectively reduce MPAP and PVR without affecting MAP, systemic vascular resistance (SVR) and CO. However, iloprost seems to be a more powerful pulmonary vasodilator, therefore we suggest iloprost inhalation in patients with severe PHT.     

右美托咪定对合并肺动脉高压患者二尖瓣置换术时血流动力学和心肌损伤的影响

目的 评价右美托咪定对合并肺动脉高压患者二尖瓣置换术时血流动力学和心肌损伤的影响.方法 择期行二尖瓣置换术的肺动脉高压患者40例,年龄18 ～64岁,性别不限,体重45～75 kg,ASA分级Ⅱ或Ⅲ级.采用随机数字表法,将其分为2组(n=20):对照组(C组)和右美托咪定组(D组).气管插管后D组经10 min静脉注射右美托咪定负荷量1μg/kg,随后以0.5 μg·kg-·h-1速率输注至术毕,C组输注等容量生理盐水.麻醉诱导后气管插管,机械通气,采用静吸复合麻醉,维持Narcotrend指数值40～50.分别于给予右美托眯定前即刻、停CPB后10 min、术毕、术后6、24h时采集中心静脉血样,测定血浆CK-MB和cTnI的水平.于右美托眯定给药前后、切皮时、劈胸骨时、CPB前后及手术结束时,采用Swan-Ganz导管及VigilanceⅡ血液动力学监测系统测定HR、MAP、肺动脉平均压(MPAP)、心排量(CO)、外周循环阻力(SVR)、肺循环阻力(PVR).记录术中血管活性药物应用情况和心脏自动复跳情况.结果 D组各血流动力学指标在切皮、劈胸骨手术刺激时维持稳定,CPB后MPAP下降并维持在较低水平.与C组比较,D组血浆CK-MB及cTnI水平、术中去氧肾上腺素用量、多巴胺用量及肾上腺素使用率降低(P＜0.05),米力农用量和心脏自动复跳率差异无统计学意义(P＞0.05).结论 合并肺动脉高压患者二尖瓣置换术中,静脉注射右美托咪定负荷量1 μg/kg,随后以0.5 μg·kg-·h-1速率输注右美托咪定,有助于维持体循环和肺循环的稳定,且产生一定程度的心肌保护作用.     

The early course of pulmonary artery hypertension in patients undergoing mitral valve replacement with cardioplegic arrest

In an effort to describe the immediate course of pulmonary hypertension following mitral valve replacement, we reviewed preoperative and postoperative data from 62 patients who underwent mitral valve replacement. Patients were divided based on the absence (Group I) or presence (Group II) of severe preoperative pulmonary hypertension, defined as a mean pulmonary artery pressure greater than or equal to 40 mm Hg. Group II patients were subdivided based on the absence (Group IIa) or presence ( Group IIb) of markedly elevated preoperative pulmonary vascular resistance indices, defined as a greater than or equal to 700 dynes . sec . cm-5 . m2. Pulmonary artery wedge pressures fell promptly following mitral valve replacement in all groups, but the course of other hemodynamic parameters varied among groups. Cardiac index increased significantly among Group I and IIb patients but not among Group IIa patients. Group I patients did not have significant changes in mean pulmonary artery pressure and pulmonary vascular resistance index. Group IIa patients had substantial reductions in mean pulmonary artery pressure while pulmonary vascular resistance index remained near 400 dynes . sec . cm-5 . m2. Group IIb patients had substantial reductions in mean pulmonary artery pressure while pulmonary vascular resistance index fell significantly to about 400 dynes . sec . cm-5 . m2. Primary valvular lesion and pharmacologic support were insignificant variables. Data from these hemodynamic groups suggest that at least three mechanisms contribute to the pulmonary hypertension seen in mitral valve disease: passive transmission of elevated left atrial pressures, reactive pulmonary arteriolar vasoconstriction, and morphologic changes in the pulmonary vasculature. The first two mechanisms appear to be rapidly reversed following mitral valve replacement. While others have described the regression of pulmonary hypertension several months following mitral valve operations, data presented here suggest that changes in pulmonary artery pressures and pulmonary vascular resistance index may occur much earlier.     

Long-term results of mitral valve surgery in patients with severe pulmonary hypertension

Mitral valve surgery was performed in 88 patients with severe pulmonary hypertension (average systolic pulmonary artery pressure, 94.7 +/- 22 mm Hg; range, 70-180 mm Hg) over a 10-year period. Sixty-four patients (73%) were in New York Heart Association Functional Class III or IV. There were 64 valve replacements and 24 open mitral commissurotomies. Operative mortality was 5.6% (5 patients) and was not related to the degree of pulmonary hypertension, surgical procedure performed, or type of valve lesion. A 100% follow-up was obtained, ranging from nine months to 10 years, with a mean of 44 months. Six late cardiac deaths (7.2%) occurred, 5 in patients with valve replacement and 1 in a patient who underwent a commissurotomy. Actuarial survival was 86 +/- 3% at five years and 83 +/- 4% at 10 years. Fourteen patients underwent right ventricular catheterization a mean of 24 months following operation. Systolic pulmonary artery pressure had decreased from a mean preoperative value of 101 +/- 22 to 40.5 +/- 7 mm Hg (p less than 0.001). Cardiac index increased by 55% of the preoperative values. Functional status improved markedly; 71 survivors (93%) were in New York Heart Association Class I or II. These results indicate that, in patients with mitral valve lesions and severe pulmonary hypertension, (1) surgical procedures can be performed with an acceptable operative mortality; (2) excellent long-term survival and functional results can be obtained; and (3) pulmonary hypertension decreases significantly after operation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Treatment with epoprostenol of pulmonary arterial hypertension following mitral valve replacement for mitral stenosis

Pulmonary hypertension frequently complicates mitral stenosis. Increased pulmonary artery pressure results from raised left atrial pressure, pulmonary arteriolar constriction, and obliterative changes in the pulmonary vascular bed, and usually responds to surgical relief of mitral stenosis. However, severe pulmonary hypertension may persist after surgical treatment of mitral stenosis. We describe a patient whose severe pulmonary hypertension following mitral valve replacement was treated successfully with continuous intravenous epoprostenol.     

吸入一氧化氮对心瓣膜置换术后肺动脉高压患者血流动力学的影响

目的：观察吸入一氧化氮（ＮＯ）对心瓣膜置换术后肺动脉高压患者血流动力学的影响。方法：选择９例心瓣膜置换术后伴肺动脉高压的病人，吸入ＮＯ０．００３％，观察三个时象点：吸入ＮＯ前；开始吸入ＮＯ后１５分钟；停止吸入ＮＯ后１５分钟。结果：吸入ＮＯ能显著降低肺动脉压和肺循环阻力指数（Ｐ＜０．０１），停止吸入ＮＯ１５分钟后，肺动脉压和肺循环阻力指数恢复到原有水平。在整个观察过程中，心率、平均动脉压、中心静脉压、肺动脉楔压、体循环阻力指数和心脏指数均无显著变化（Ｐ＞０．０５）。结论：吸入ＮＯ具有选择性肺血管扩张作用，是治疗心瓣膜置换术后肺动脉高压的较理想药物。     

Inhaled nitric oxide after mitral valve replacement in patients with chronic pulmonary artery hypertension.

Patients with mitral valve disease can develop pulmonary artery hypertension that persists after mitral valve replacement. In 1987, nitric oxide (NO) was reported to be an important factor accounting for the biologic activity of endothelium-derived relaxing factor. Inhaled NO was subsequently reported to be a selective pulmonary vasodilator in animals and patients. Therefore we investigated the vasodilating effect of inhaled NO in patients with mild pulmonary artery hypertension after mitral valve replacement. Six patients who underwent mitral valve replacement for mitral stenosis presented with a mean pulmonary artery pressure greater than 25 mmHg within 24 h after surgery. During mechanical ventilation at FIO2 0.5, NO (36.8-38.4 ppm) was breathed for 10 min. Hemodynamic data were recorded before NO, after 10 min of NO inhalation, and 30 min after the end of NO inhalation. Statistically significant (P < 0.05) hemodynamic response to inhaled NO included a transient decrease in systolic (-10%), diastolic (-8%), and mean (-10%) pulmonary artery pressures; a decrease in pulmonary vascular resistance (-22%); an increase in mixed venous hemoglobin O2 saturation (+6%); and a decrease in arteriovenous O2 content difference (-7%). During NO inhalation, there was no change in systemic arterial or pulmonary wedge pressures. Methemoglobin levels remained < 1%. Inhalation of this concentration of NO for 10 min causes transient pulmonary artery vasodilation and hemodynamic improvement in patients with mild chronic pulmonary artery hypertension after mitral valve replacement.     

肢体远隔缺血预处理对心肺转流心脏瓣膜置换术患者肺功能的影响

目的评价肢体远隔缺血预处理(remote ischemic preconditioning,RIPC)对心肺转流(cardiopulmonary bypass,CPB)心脏瓣膜置换术患者肺功能的影响。方法择期在CPB下行心脏瓣膜置换术患者70例,男32例,女38例,年龄18~70岁,体重45~90 kg,ASAⅡ或Ⅲ级,采用随机数字表法将患者分为两组,每组35例。R组于气管插管后10 min采用测压袖带在患者右上肢上臂,给予3个循环的5 min缺血(袖带充气,压力≥200 mm Hg)及5 min再灌注(袖带放气至0 mm Hg)处理。C组将袖带绑于患者右上肢,但不进行充气及放气操作。分别于气管插管后10 min(T_0)、主动脉开放后1 h(T_1)、术后6 h(T_2)、12 h(T_3)、24 h(T_4)采集桡动脉血样,进行血气分析,计算氧合指数(PaO_2/FiO_2)和肺泡动脉血氧分压差(A-aDO_2),肺动态顺应性(Cd)和肺静态顺应性(Cs)。记录出院时肺部不良事件情况。结果与T0时比较,T_1~T_4时两组PaO_2/FiO_2明显降低,T_2~T_4时A-aDO_2明显降低,T_3时C组Cs、Cd明显升高,T_2、T_3时R组Cs、Cd明显升高(P0.05)。与C组比较,T_2、T_3时R组Cs、Cd明显提高,T0~T4时PaO_2/FiO_2、A-aDO_2两组差异无统计学意义。与C组比较,R组肺部不良事件发生率明显降低(P0.05)。结论肢体远隔缺血预处理能够改善心脏瓣膜置换术患者的肺顺应性,减少术后肺部不良事件的发生。     

Influence of age on outcomes in patients undergoing mitral valve replacement

BACKGROUND: Although increasing age has been associated with greater risk of mortality for patients undergoing mitral valve replacement, it is less clear whether this elevated risk is related to age-related differences in comorbidity or other clinical characteristics. METHODS: A population of 31,688 patients from The Society of Thoracic Surgeons National Cardiac Database undergoing mitral valve replacement either alone or in combination with coronary artery bypass grafting or tricuspid surgical procedures from 1997 to 2000 was examined to assess age-related variation in clinical features, morbidity, and mortality. Multivariable logistic regression was used to determine the effect of age after adjusting for other known risk factors. A classification tree was used to identify low-risk elderly (> or = 75 years) patients. RESULTS: Operative mortality increased four-fold from 4.1% in patients aged less than 50 years up to 17.0% in patients aged 80 years or more. Similarly, major operative complications (stroke, prolonged ventilation, reoperation for bleeding, renal failure, and sternal infection) also increased with age, rising from 13.5% (age < 50 years) to 35.5% (age > or = 80 years). Multivariable adjustment attenuated the odds of operative mortality, but age remained a significant risk factor. After adjusting for other patient risk factors, age accounted for 13% and 10% of the explainable risk for mortality and morbidity, respectively. Among the elderly, four variables (hemodynamic instability, New York Heart Association class IV, renal failure, and concomitant coronary artery bypass grafting) were identified to distinguish levels of risk, from operative mortality rates exceeding 31% to those with 7.7% mortality. CONCLUSIONS: Operative mortality and morbidity rise with increasing age of patients undergoing mitral valve replacement. Although this excess risk is partially a result of increased comorbid burden and other operative factors, age remains an independent powerful risk factor for operative risk for mitral valve replacement. Understanding the relationship of age with other risk factors for mitral valve replacement can help stratify risk, enabling physicians to identify lower risk patients.     

Inhaled iloprost to control pulmonary artery hypertension in patients undergoing mitral valve surgery: a prospective, randomized-controlled trial

Background: Pulmonary hypertension (PHT) is common in patients undergoing mitral valve surgery and is an independent risk factor for the development of acute right ventricular (RV) failure. Inhaled iloprost was shown to improve RV function and decrease RV afterload in patients with primary PHT. However, no randomized‐controlled trials on the intraoperative use of iloprost in cardiac surgical patients are available. We therefore compared the effects of inhaled iloprost vs. intravenous standard therapy in cardiac surgical patients with chronic PHT. Methods: Twenty patients with chronic PHT undergoing mitral valve repair were randomized to receive inhaled iloprost (25 μg) or intravenous nitroglycerine. Iloprost was administered during weaning from cardiopulmonary bypass (CPB). Systemic and pulmonary haemodynamics were assessed with pulmonary artery catheterization and transoesophageal echocardiography. Milrinone and/or inhaled nitric oxide were available as rescue medication in case of failure to wean from CPB. Results: Inhaled iloprost selectively decreased the pulmonary vascular resistance index after weaning from CPB (208 ± 108 vs. 422 ± 62 dyn·s/cm⁵/m², P<0.05), increased the RV‐ejection fraction (29 ± 3% vs. 22 ± 5%, P<0.05), improved the stroke volume index (27 ± 7 vs. 18 ± 6 ml/m², P<0.05) and reduced the transpulmonary gradient (10 ± 4 vs. 16 ± 3 mmHg, P<0.05). In all patients receiving inhaled iloprost, weaning from CPB was successful during the first attempt. In contrast, three patients in the control group required re‐institution of CPB and had to be weaned from CPB using rescue medication. Conclusions: In patients with pre‐existing PHT undergoing mitral valve surgery, inhaled iloprost is superior to intravenous nitrogylycerine by acting as a selective pulmonary vasodilator, reducing RV afterload and moderately improving RV‐pump performance.     

感染性心内膜炎患者二尖瓣置换和成型术的效果

目的比较感染性心内膜炎患者行二尖瓣置换和成型手术的临床特点和转归。方法回顾性分析2013年1月至2016年12月在北京协和医院行手术治疗的、累及二尖瓣的感染性心内膜炎患者55例,男24例,女31例,年龄19～77岁,ASAⅡ-Ⅳ级,根据患者所行手术分为两组:二尖瓣置换术组(Z组,n=15)和二尖瓣成型术组(C组,n=40)。比较两组致病菌、临床表现、超声心动图表现、是否入住ICU、住院时间、术后并发症等。结果链球菌是感染性心内膜炎最常见的病原菌,发热、新出现的心脏杂音和贫血是最常见的临床表现。Z组贫血、心力衰竭、术后入ICU比例明显高于C组(P 0.05)。两组超声心动图表现、住院时间和术后并发症差异无统计学意义。结论对于有手术指征的感染性心内膜炎患者,合理选择手术方式可以改善患者预后。     

双心房输注对二尖瓣置换术患者体外循环后肺动脉压的影响

目的 评价双心房输注对二尖瓣置换术患者体外循环后肺动脉压(PAP)的影响.方法 择期行二尖瓣置换术合并肺动脉高压[平均肺动脉压(MPAP)＞50 mm Hg]的患者20例,年龄22～53岁,体重34～57kg,心功能分级Ⅱ或Ⅲ级,随机分为2组(n=10):右心房输注组(R组)和双心房输注组(B组).麻醉诱导后右颈内静脉穿刺置入Swan-Ganz三腔漂浮导管,监测CVP、PAP、肺毛细血管楔压(PCWP)和CO.R组经中心静脉输注前列腺素E130～150 ng·kg-1·min-1和去氧肾上腺素0.2～0.6μg·kg-1·min-1.B组经中心静脉输注前列腺素E130～150 ng·kg·min-1,经左心房输注去氧肾上腺素0.2～0.6μg·kg-1·min-1.分别于给药前5 min(T0)、给药后5 min(T1)、10 min(T2)、30 min(T3)和60 min(T4)时记录MAP、HR、MPAP、PCWP、CVP和CO,计算肺血管阻力指数(PVRI)、体循环血管阻力指数(SVRI)和CI.结果 与T0时比较,R组T1-4时MAP、MPAP、PCWP和PVRI降低,CI升高(P＜0.05),HR、CVP和SVRI差异无统计学意义(P＞0.05),B组T1-4时MAP、CI和SVRI升高,HR、MPAP、PCWP、CVP和PVRI降低(P＜0.05);与R组比较,B组MAP、CI和SVRI升高,HR、MPAP、PCWP、PVRI和CVP降低(P＜0.05).结论 双心房输注可降低二尖瓣置换术患者体外循环后肺动脉压和肺血管阻力.     

Desflurane versus propofol in patients undergoing mitral valve surgery

OBJECTIVE: Myocardial ischemic damage is reduced by volatile anesthetics in patients undergoing coronary artery bypass graft surgery, but it is unknown whether this benefit exists in patients undergoing valvular surgery with ischemia-reperfusion injury related to cardioplegic arrest and cardiopulmonary bypass. This study compared cardiac troponin release in patients receiving either volatile anesthetics or total intravenous anesthesia for mitral valve surgery. DESIGN: Randomized controlled study. SETTING: University hospital. PARTICIPANTS: One hundred twenty patients undergoing mitral valve surgery. Interventions: Fifty-nine patients received the volatile anesthetic desflurane for 30 minutes before cardiopulmonary bypass, whereas 61 patients received a total intravenous anesthetic with propofol. All patients had an opioid-based anesthetic for the mitral valve surgery. MEASUREMENTS AND MAIN RESULTS: Peak postoperative troponin I release was measured as a marker of myocardial necrosis after mitral valve surgery. Patient mean age was 60 years, and 54% were men. There was no significant (p = 0.7) reduction in median (25th-75th percentiles) postoperative peak troponin, 11.0 (7.5-17.4) ng/dL in the desflurane group versus 11.5 (6.9-18.0) ng/dL in the propofol group. A subgroup of patients with concomitant coronary artery disease had the expected reduction (p = 0.02) of peak troponin I in those receiving desflurane, 14.0 (9.7-17.3) ng/dL, when compared with patients receiving total intravenous anesthesia, 31.6 (15.7-52.0) ng/dL. CONCLUSIONS: Myocardial damage measured by cardiac troponin release was not reduced by volatile anesthetics in patients undergoing mitral valve surgery, whereas it was reduced in patients with concomitant coronary artery disease.     

Surgical treatment of tricuspid insufficiency in patients undergoing mitral valve replacement

During the past eight years, 46 of the 106 patients who underwent mitral valve replacement were associated with tricuspid insufficiency. No surgical correction was performed (14 cases) in cases of slight tricuspid insufficiency. Tricuspid annuloplasty (11 cases) or valve replacement (21 cases) was employed according to the severity of insufficiency. In the non-repair group, the mortality rate was fairly low (21 per cent), but the postoperative status was the least satisfactory by the NYHA classification. Tricuspid insufficiency was significantly reduced only in two of these 14 cases after the mitral valve replacement. In the tricuspid annuloplasty group, although the technique of tricuspid annuloplasty did not always correct insufficiency completely, only one patient died of residual insufficiency. The cardiac output measured with Minnesota Impedance Cardiograph increased postoperatively in proportion to stress in this group. In the tricuspid valve replacement group, cardiac catheterization studies revealed hemodynamic improvement at rest in all, but cardiac output during exercise remained unchanged or decreased in some cases. Now we consider that tricuspid insufficiency with advanced mitral valve disease, even of a slight degree, should be surgically treated and that annuloplasty has more obvious hemodynamic benefits than valve replacement.     

异氟醚预处理对心脏联合瓣膜置换术患者左心功能的影响

目的观察异氟醚预处理对心脏手术患者左心功能的影响。方法择期二尖瓣和主动脉瓣联合置换术患者30例,随机均分为两组:G组麻醉诱导后吸入1.1%~1.2%的异氟醚30min,洗脱15 min;C组不吸入异氟醚作为对照。于吸入异氟醚前(T0)、主动脉开放30 min(T1)、关胸后(T2)、主动脉开放6 h(T3)、12 h(T4)和24 h(T5)通过肺动脉导管观察相关左心功能指标,于T0、T1、T3~T5时测血浆N端脑钠素前体肽(NT-proBNP)浓度。结果与T0时比较,两组MAP在T1~T4、肺动脉阻塞压(PAOP)在T2~T5、全身血管阻力(SVR)在T1~T5时均降低(P0.05或P0.01),两组每搏指数(SI)、心脏指数(CI)和左心室每博做功指数(LVSWI)在T1~T5时均升高(P0.05或P0.01)。与C组比较,G组PAOP在T5时降低,混合静脉血氧饱和度(SvO2)在T2~T5时升高,SI在T4、T5时升高,CI和LVSWI在T3~T5时升高,NT-proBNP在T4、T5时降低。结论异氟醚预处理对心脏联合瓣膜置换术患者主动脉开放12~24 h左心功能可能有改善作用。