多层螺旋CT对冠状动脉桥血管的评价

目的评价16层螺旋CT对冠状动脉桥血管的显示能力。方法回顾性分析17例冠状动脉搭桥术(CABG)后患者的CT和选择性桥血管造影的资料,男15例,女2例,年龄51～78岁,平均(67±7)岁,术后6～85个月,平均(32±19)个月。共40支桥血管,原位乳内动脉13支,游离桡动脉11支,游离大隐静脉16支。由两位有丰富心血管影像诊断学经验的医生采用双盲法阅片,并取得一致结果。评价指标包括CT成像中桥血管的可评价性、有无闭塞或狭窄(管径缩小50%～99%)。结果所有40支桥血管均可评价,CT准确诊断5支桥血管闭塞和1支狭窄外,各有1例假阳性,其诊断桥血管闭塞与狭窄的敏感性、特异性达100%和97%,准确率分别为97.5%和97.1%。发生闭塞的血管与桥血管的类型和分布无关。结论16层螺旋CT是一种值得信赖的无创性随访研究桥血管通畅性的影像学方法。     

Intra-operative quality assessment of coronary artery bypass grafts.

Early coronary artery bypass graft (CABG) failure is a troubling complication that may result in a wide range of problems, including refractory angina, myocardial infarction, low cardiac output, arrhythmia, and fatal heart failure. Early graft failures are related to poor quality and size of the distal native vascular bed, coagulation abnormalities, or technical problems involving the graft conduits and anastomoses. Unfortunately, graft failure is difficult to detect during surgery by visual assessment, palpation, or conventional monitoring. We evaluated the accuracy and utility of a transit-time, ultrasonic flow measurement system for measurement of CABGs. There were no differences between transit-time measurements and volumetric-time collected samples in an in vitro circuit over a range of flows from 10 to 100ml/min (Bland and Altman Plot, 1.96 SD). Two hundred and ninety-eight CABGs were examined in 125 patients. Graft flow rate was proportional to the target vessel diameter. Nine technical errors were detected and corrected. Flow waveform morphology provided valuable information related to the quality of the anastamosis, which led to the immediate correction of technical problems at the time of surgery.     

冠脉搭桥术后桥管的超声检查方法研究

目的探讨经胸超声检查冠脉搭桥术后桥管的显像方法及血流状态。方法采用经胸超声冠脉血流显像与高频血管显像相结合对左乳内动脉原位转流至左前降支、大隐静脉-右冠状动脉及大隐静脉-左回旋支桥管进行检查。结果左乳内动脉桥管、大隐静脉-右冠状动脉及大隐静脉-左回旋支桥管显示率分别为100%、93.75%和20%。左乳内动脉及大隐静脉桥管的血流均为舒张期为主的双期血流;左乳内动脉桥管的舒张期血流速度及流速时间积分大于大隐静脉桥管（P〈0.05）。结论经胸超声是术后桥管检查的较好方法,可用于无创的评估术后桥管血流状态。     

Calcium-channel antagonists and nitrates in coronary artery bypass patients receiving radial artery grafts

OBJECTIVE: To review the literature assessing the role of vasodilators for the prevention of vasospasm leading to graft failure in patients receiving the radial artery (RA) as a conduit in coronary artery bypass grafting (CABG). DATA SOURCE: A MEDLINE search (January 1966-May 2000) was performed using calcium-channel antagonists, nitrates, radial artery, and coronary artery bypass as key words. English-language articles were identified, and the references of these articles were used to further identify pertinent articles. DATA SYNTHESIS: RAs can be used as conduits in CABG. It has been suggested that failure of these grafts may be due to vasospasm, leading to occlusion observed angiographically. Calcium-channel antagonists and nitrates have been proposed as a means of preventing vasospasm and subsequent graft failure. CONCLUSIONS: Currently published data on the use of calcium-channel antagonist or nitrate therapy as prophylaxis against vasospasm in patients receiving RA grafts are inconclusive. Systematic evaluations of currently available pharmacologic agents are needed to guide clinical practice in this area.     

Gene therapy to prevent occlusion of venous bypass grafts

Revascularization with vein grafts is standard surgical therapy for occlusive arterial diseases. Autologous saphenous vein grafts are important conduits for repairing blocked coronary arteries and are used in the majority of vein graft procedures. Up to 50% of saphenous vein grafts will be occluded during the first decade after surgery. Vein graft occlusion occurs as a result of neointimal hyperplasia, which takes place in response to hemodynamic changes and vessel wall injury, and is characterized by the migration and proliferation of vascular smooth muscle cells. Intimal hyperplasia is further complicated by the concomitant development of atherosclerosis and thrombosis. In the absence of effective pharmacological interventions for the treatment and prevention of occlusive vein graft disease, gene therapy has emerged as a potential therapeutic alternative. Gene therapy could improve vein graft patency by reducing early thrombosis, neointimal hyperplasia and atherosclerosis. In this review we will summarize the emerging applications of gene therapy as a therapeutic tool in occlusive vein graft disease.     

Evaluation of venous bypass grafts from aorta to coronary artery by inert gas desaturation and direct flowmeter techniques

Blood flow through aorta-to-coronary artery bypass grafts has been measured selectively in 16 patients at or within 6 wk after operation. Inert gas desaturation curves were obtained from coronary venous blood samples after a 7-15 min infusion of dissolved H(2) directly into the graft. Samples were analyzed chromatographically and curves resolved to 1-3% of initial H(2) concentrations. Average flow per unit volume (F/V) was 67+/-21 (sd) ml/min per 100 g. Semilogarithmic plots showed F/V to be distributed heterogeneously in every case. In nine studies at operation, H(2) measurements of average F/V were combined with electromagnetic measurements of total flow to estimate revascularized tissue mass. Electromagnetic flows ranged from 25 to 170 ml/min and averaged 69 ml/min. Tissue mass ranged from 46 to 155 g and averaged 88 g. We conclude that bypass grafts provide nutritive flow to significant amounts of myocardium at and shortly after operation. However, nutritive flow is not distributed evenly throughout the revascularized segment. The majority of the segment has a F/V within the accepted range of normal but there remain areas in which F/V is reduced significantly. The combination of inert gas and electromagnetic techniques allows a revascularized area to be characterized in terms of total flow, F/V, and tissue mass.     

多层螺旋CT在冠状动脉搭桥术后的临床应用

目的评价多层螺旋CT(MSCT)在冠状动脉搭桥术后的应用价值。方法对40例冠状动脉搭桥术后患者,共有搭桥血管93条(乳内动脉30条,大隐静脉63条)。对40例患者分别行螺旋CT增强扫描和选择性冠状动脉造影(SCA)检查。所有MSCT检查采用回顾性心电门控技术、分段数据采集方式和选择75%的时间相位窗,对扫描数据进行后处理,由两位富有经验的医师评估并与SCA结果对照。结果所有近端桥血管及71.4%的远端搭桥血管通过MSCTA可显示,12条桥血管闭塞,66条通畅,13条有不同程度狭窄,1条远端桥血管狭窄并得到SCA证实,有4条假阳性,1条假阴性导致敏感性为94.5%,特异性为95.7%,阳性预测值80.4%,阴性预测值96.3%。结论多层螺旋CT可作为一种可靠的检查手段用于冠状动脉搭桥术后的评估。     

冠状动脉旁路术后预防下肢深静脉血栓形成的护理

目的 探讨在围术期实施护理干预对预防冠状动脉旁路搭桥术后下肢深静脉血栓形成(DVT)的疗效.方法 对照组为未实行护理干预的前3年患者201例,其术后均采用传统的围术期护理方法,观察组为实行护理干预3年来患者298例,在传统护理基础上实施有针对性的护理干预,比较两组患者DVT发生情况.结果 观察组患者术后下肢深静脉血栓、下肢肿胀及疼痛的发生率为1.54％,明显低于对照组的3.87％,差异有统计学意义(x2=5.26,P＜0.01).结论 围术期护理干预能有效降低冠状动脉旁路搭桥术后下肢深静脉血栓的形成.     

多层螺旋CT血管成像评价冠状动脉血管旁路移植术

目的评价多层螺旋CT(MSCT)冠状动脉成像对冠状动脉桥血管的临床价值。方法28例患者的69条冠状动脉桥血管接受16层和64层螺旋CT冠状动脉成像。对桥血管成像进行影像质量评估,使用多元线性回归方法评估患者心率、心率波动幅度、呼吸运动以及不同CT扫描机对冠状动脉成像质量的影响。其中10位患者26条桥血管的CT血管成像结果与冠状动脉血管造影结果进行对比。结果呼吸运动伪影与冠状动脉桥血管成像质量呈负相关,相关系数为-0.838。64层CT扫描机的影像质量高于16层CT扫描机的影像质量。以CAG结果为参考标准,MSCT冠脉成像诊断桥血管及吻合口狭窄的特异性和敏感性分别为95.7%和92.3%。结论MSCT可以提供可靠的冠状动脉桥血管影像以及较高的诊断准确性。     

Transthoracic Doppler validation in mammary artery grafts after minimal invasive direct coronary artery bypass operation.

OBJECTIVE: This study was performed to validate noninvasive transthoracic Doppler ultrasound (TTD) with simultaneous invasive Doppler guidewire measurements in patients after minimal invasive direct coronary artery bypass operation. METHODS: A total of 14 patients were examined 3 to 8 days after minimal invasive direct coronary artery bypass operation. TTD was performed to measure systolic and diastolic peak velocities of the left internal mammary artery (LIMA) at rest and during adenosine-induced hyperemia. Simultaneous Doppler guidewire measurements were performed. RESULTS: LIMA flow was detected in 12 of 14 patients (86%). There was high agreement between TTD and Doppler guidewire measurements of LIMA flow velocities (systolic peak velocity: r = 0.86, y = 11.3 + 0.82x +/- 7.9; diastolic peak velocity: r = 0.95, y = 5.7 + 1.02x +/- 7.5; average peak velocity: r = 0.95, y = 5.2 + 0.94x +/- 5.4; and flow velocity reserve: r = 0.97, y = 5.2 + 0.99x +/- 4.5). CONCLUSION: TTD represents an accurate method to evaluate flow velocities and flow velocity reserve of LIMA bypass grafts even in the early phase after minimal invasive direct coronary artery bypass operation.     

320排容积CT在冠状动脉搭桥术后桥血管成像中的应用

目的：评价320排容积CT对冠状动脉搭桥术后桥血管成像的应用价值。方法：55例搭桥术后患者（男36例）,共计126条桥血管,其中52条动脉桥,61条静脉桥,13条序贯桥血管。所有患者在术后3~9个月进行320排容积CT桥血管成像检查,对所有病例图像进行后处理重建,包括多平面重组（MPR）、曲面重组（CPR）以及容积再现（VR）等。由2位有经验的放射科医生对重建图像进行观察,对桥血管成像质量进行评估（优、良、差）,并对桥血管的通畅性（通畅、轻度狭窄、中度狭窄、重度狭窄）进行初步评价。结果：55例患者均顺利完成冠状动脉桥血管320排容积CT成像检查,在待评价的126条桥血管中,116条桥血管显影,其中图像质量优97条（83.6％）、良19条（16.4％）,差0条（0％）,10条桥血管未见显影考虑闭塞。此外,发现8条动脉桥血管管壁存在钙化,5条动脉桥血管、5条静脉桥以及2条序贯桥血管可见近端或远端吻合口不同程度狭窄。结论：320排容积CT能够清晰显示冠状动脉桥血管,并且能够对桥血管及吻合口狭窄情况进行评估,是一种良好的无创性冠状动脉桥血管成像方法。     

冠状动脉桥血管的多层螺旋CT和造影评价

目的:评价多层螺旋CT在显示冠状动脉桥血管中的临床应用价值。方法:21例冠状动脉血管旁路移植术后患者行多层螺旋CT血管成像及常规造影检查,分析CT诊断桥血管通畅性和狭窄的可靠性。结果:多层螺旋CT血管成像成功检测出21例患者共45支桥血管,15支桥血管闭塞,30支桥血管通畅,10支共16处狭窄,5支桥血管明显狭窄(>50%)8处,5支桥血管显示轻度狭窄(<50%)病变8处,MSCT评价桥血管闭塞和明显狭窄和导管造影完全符合。结论:多层螺旋CT尤其是64层CT能够准确地评价冠状动脉桥血管及吻合口的通畅性和狭窄情况,可以作为临床上对冠状动脉桥血管可疑病变的一种常规的无创性检查手段。     

Non-selective intra-arterial digital subtraction angiography for the assessment of coronary artery bypass grafts

Non-selective intra-arterial digital subtraction angiography (DSA) was performed immediately before selective coronary and bypass angiography in 33 consecutive symptomatic patients 48± 30 months after coronary surgery, for the assessment of 75 coronary bypass grafts. Forty ml of non-ionic, low-iodine content contrast medium (iohexol) were injected into the ascending aorta at 10–20 ml/sec through a 7 or 8 F femoral pigtail catheter. Electrocardiogram-triggered images were acquired on a Siemens Digitron II apparatus in multiple projections in 24 patients and in a single projection in 9 patients. The results of this technique were compared by two independent angiographers with those of selective graft angiography in the same patients. Patency was shown by DSA in 45 of 54 grafts confirmed to be open by selective angiography (sensitivity 83%). Of 21 occluded grafts, stumps were clearly visible at selective angiography in 18 and at DSA in 9 (sensitivity for graft stumns = 50%, p<0.01) Of 54 patent grafts with selective angiogranhy. the distal anastomosis could be visualized by DSA in 28 (52%), but the resolution was comparable to selective angiography in 20 grafts (37%) only. A non-significant difference in the sensitivity of DSA was observed between patent saphenous grafts to the left anterior descending coronary artery versus all other coronary arteries (95 vs 85%, respectively), while only 1 of 5 patent left internal mammary artery grafts to the left anterior descending coronary artery was visualized. In 16 of 50 grafts (32%) visualized in a second projection substantial additional diagnostic information was obtained. In conclusion, non-selective intra-arterial electrocardiogram-triggered DSA can visualize patent saphenous grafts with a high sensitivity and may be a useful screening tool for bypass grafts patency; false negatives, however, and poor visualization of distal anastomoses limit its routine clinical use.     

128层螺旋CT对冠状动脉搭桥术后桥血管病变的诊断研究

目的 探讨应用128层螺旋CT对冠状动脉旁路移植手术(CABG)术后桥血管病变的诊断价值.方法 对46例CABG术后(术后12～76个月)的患者行128层螺旋CT造影(MSCTA)检查,共检查133条桥血管,其中乳内动脉44条,大隐静脉89条.MSCTA检查后3～10d再行冠状动脉造影(CAG)检查,结果与MSCTA检查结果进行比较.结果 在133条桥血管中,MSCTA显示桥血管闭塞17条,桥血管狭窄(狭窄＞50％)20条.CAG结果显示桥血管闭塞17条,与MSCTA显示结果一致;桥血管狭窄(＞50％)有21条;与MSCTA检查结果比较,MSCTA检查结果假阳性1例,假阴性2例.计算MSCTA检查的敏感性为94.7％,特异性98.9％,阳性预测值97.3％,阴性预测值97.9％.结论 128层MSCTA检查可以比较准确地判断CABG术后桥血管的病变情况,是评价CABG术后桥血管病变的一种较好的无创伤检查方法.     

间断小切口采取大隐静脉在冠状动脉旁路移植中的临床应用

目的总结冠状动脉旁路移植术中使用间断小切口采取大隐静脉的经验,并与传统长切口作比较。方法选择行冠状动脉旁路移植术患者60例,随机分成两组,每组30例。一组采用间断小切口取大隐静脉（间断小切口组）,另一组采用传统长切口取大隐静脉（传统长切口组）。比较两组切口长度、大隐静脉总长度、采取时间、下肢切口缝合时间、切口并发症等指标。结果两组在采取大隐静脉的过程中均未发生大隐静脉主干损伤及移植血管质量相关的手术并发症。与传统长切口组比较,间断小切口组切口长度、下肢切口缝合时间短,切口近期并发症发生率低（P〈0.05）,大隐静脉总长度、采取时间、切口远期并发症发生率相近,差异无统计学意义（P〉0.05）。结论间断小切口采取大隐静脉效果良好,较传统长切口有助于术后切口美容及减少术后下肢切口并发症。     

Imaging platelet deposition with 111In-labeled platelets in coronary artery bypass grafts in dogs.

At 8 and 32 hours after saphenous vein aortocoronary artery bypass graft surgery in four dogs, images of the grafts were obtained with a gamma camera after intravenous injection, 2 hours postoperatively, of autologous platelets labeled with indium-111. The location of platelet deposition could be accurately estimated from the scintiphotos. In vitro radioactivity counting of the segments of the isolated grafts showed 4 to 15 times greater activity in the grafts than in blood and 25 to 100 times greater activity than in normal myocardium. This was sufficient for delineating accurately the area of platelet deposition. This noninvasive technique may be a promising tool for a better understanding of the role played by platelets in the process of occlusion of saphenous vein bypass grafts in man.