Retrograde internal mammary to coronary artery anastomoses

In an effort to expand the utilization of the internal mammary artery (IMA) for revascularization of the distal coronary artery branches, distally pedicled retrograde internal mammary arteries (retro-IMA) were evaluated in 10 mongrel dogs with a mean weight of 38 +/- 13 kg. One IMA was transected at it's origin (retro-IMA) and compared to the contralateral IMA which was transected at the level of the 5th intercostal space. At a mean systemic pressure of 68 +/- 15 mmHg the mean pressure measured at the tip of the IMAs with antegrade flow was 63 +/- 14 mmHg in the retro-IMAs with retrograde flow (p less than 0.05; pressure ratio 0.8). With the same mean systemic pressure, mean antegrade free flow of the IMAs was assessed 97 +/- 43 ml/min versus 48 +/- 13 ml/min in the retro-IMAs with retrograde flow (p less than 0.005; flow ratio 0.5). Left retro-IMA to coronary artery anastomosis was performed in 6 animals to the distal left anterior descending (LAD) coronary artery and in 2 animals to the distal left obtuse marginal branch. Right retro-IMA to coronary artery anastomosis to the right posterior descending coronary artery was performed in 2 animals. The LAD coronary artery was ligated proximally to the retro-IMA to coronary artery anastomosis while the retro-IMA remained crossclamped. After documentation of significant ischemia (EKG, left atrial pressure), the crossclamp of the retro-IMA graft was removed. Subsequent normalisation of EKG and left atrial pressure occurred in all animals. We conclude that the canine retro-IMA delivers significant retrograde flow and discuss a possible use in humans.     

Long-term patency of saphenous vein and left internal mammary artery grafts after coronary artery bypass surgery: results from a Department of Veterans Affairs Cooperative Study

OBJECTIVES: This study defined long-term patency of saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts. BACKGROUND: This VA Cooperative Studies Trial defined 10-year SVG patency in 1,074 patients and left IMA patency in 457 patients undergoing coronary artery bypass grafting (CABG). METHODS: Patients underwent cardiac catheterizations at 1 week and 1, 3, 6, and 10 years after CABG. RESULTS: Patency at 10 years was 61% for SVGs compared with 85% for IMA grafts (p < 0.001). If a SVG or IMA graft was patent at 1 week, that graft had a 68% and 88% chance, respectively, of being patent at 10 years. The SVG patency to the left anterior descending artery (LAD) (69%) was better (p < 0.001) than to the right coronary artery (56%), or circumflex (58%). Recipient vessel size was a significant predictor of graft patency, in vessels >2.0 mm in diameter SVG patency was 88% versus 55% in vessels 2.0 mm in diameter.     

Midterm results for use of the skeletonized gastroepiploic artery graft in coronary artery bypass.

BACKGROUND: To improve the long-term results of coronary artery bypass grafting (CABG), several arterial conduits have been used, including the skeletonized right gastroepiploic artery (GEA) graft. METHODS AND RESULTS: The skeletonized GEA graft was used for CABG in 223 patients over a 6-year period (208 males, 15 females, mean age 64 years). 1-, 2- and 3-vessel and left main trunk disease was noted in 1, 28, 122 and 72 patients, respectively. Internal thoracic artery, radial artery and saphenous vein grafts were concomitantly used in 217 (97%), 73 (33%) and 41 (18%) patients, respectively, and the mean number of grafts was 3.5. The sites of GEA grafting were 1 anterior descending, 10 diagonal, 97 circumflex, and 185 right coronary arteries, with 154 single in-situ, 33 free and 36 composite grafts, including 56 sequential grafts. There was 1 (0.4%) operative death. New Q wave was noted in 2 (0.9%) patients. Postoperative angiography revealed 97.6% early postoperative (within 1 month) and 91.5% midterm (mean 27 months) patency rates for GEA grafts. The cumulative 4-year patency rate of the skeletonized GEA graft was 86.4%. CONCLUSION: The skeletonized GEA is a safe and effective arterial conduit for CABG.     

Short- and medium-term study of arterial grafts and native coronary circulation after in situ implant of the internal mammary artery

The internal mammary artery (IMA) is being increasingly utilized as a conduit for myocardial revascularization, based on its higher long-term patency. The aim of this study is the serial assessment of the changes of native coronary vessels after IMA coronary anastomosis. Twenty-six consecutive patients (24 males and 2 females, mean age 56.4 years) received an IMA graft on the left anterior descending (LAD) artery. IMA coronary anastomosis was single in 11 patients and double (LAD and diagonal branch) in the remaining 15 cases. In 23 patients (88.5%) at least one associated saphenous vein graft was inserted. Post-operatively, no new Q waves or low-output syndromes were observed. Follow-up angiographic study, including selective opacification of the IMA graft, was carried out after 1 month and after 1 year. The cumulative patency rate of IMA grafts was 97.7% after 1 month. The LAD stenosis proximal to the IMA anastomosis progressed to total occlusion in 6 patients (28.5%), all of them with a preoperative stenosis ranging from 90 to 99%; its diameter remained unchanged in 6 patients (28.5%), while a reduction of the coronary narrowing greater than or equal to 20% was observed in 9 patients (43%). Preoperatively, the LAD stenosis of the latter groups ranged from 70 to 90%. Severity of residual stenosis and relative diameters of LAD artery and IMA graft influenced the competitive flow distribution through these vessels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with internal mammary arteries in children with Kawasaki disease

BACKGROUND. Saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts have been used for coronary artery bypass grafting. In adult patients with bypass grafting for atherosclerotic coronary artery disease, IMA grafts have been reported to have long-term patency; however, results are conflicting on whether the graft is sufficient to meet increased myocardial oxygen demand during exercise. There have been no studies on hemodynamics and blood flow during exercise after bypass grafting with IMA in pediatric patients with Kawasaki disease. METHODS AND RESULTS. We studied 17 pediatric patients with Kawasaki disease (average age, 7.5 +/- 3.1 years), who underwent coronary artery bypass grafting with the IMA. The average number of coronary artery bypass grafts was 2.1 +/- 0.7/patient. For all patients, the left IMA was anastomosed to the left anterior descending coronary artery; for eight patients, the right IMA was also anastomosed to the right coronary artery. In addition, 11 SVGs were used. The postoperative patency rates after 1 month were 100% with the IMA graft and 91% with SVG. One year after the operation, the patency rates were 100% with IMA and 50% with SVG. Hemodynamics during exercise were measured with a bicycle ergometer, and coronary sinus blood flow was measured by the continuous thermodilution method in six patients. The relation between delta LVEDP (the difference between left ventricular end-diastolic pressure at rest and during exercise) and delta SVI (the difference between the stroke volume index at rest and during exercise) was analyzed. Four of six patients had reduced cardiac function before operation (delta LVEDP, positive; delta SVI, negative). However, after the operation, all patients demonstrated improvements in cardiac function during exercise (delta LVEDP, positive; delta SVI, positive). Coronary sinus flow per left ventricular mass increased after operation from 70 +/- 46 to 87 +/- 56 ml/min at rest (p less than 0.05) and from 139 +/- 118 to 183 +/- 150 ml/min during exercise (p less than 0.05). CONCLUSIONS. In conclusion, this study reveals improvements in both hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with IMA grafts in pediatric patients with Kawasaki disease.     

Triple arterial coronary revascularization using the radial artery and bilateral internal mammary arteries versus the gastroepiploic artery and bilateral internal mammary arteries.

Arterial grafts are frequently used in modern coronary artery bypass grafting (CABG) and the benefit of the 2 internal mammary arteries (IMA) has already been established. However, the choice of the third arterial conduit, in addition to the IMA, is controversial. We have retrospectively analized perioperative and the follow-up results of patients who underwent CABG with triple arterial bypass using either the radial artery (RA) or the gastroepiploic artery (GEA) in conjunction with the bilateral IMA (BIMA). Between December 1995 and June 2001, 1,516 consecutive isolated CABG operations were performed at Shin-Tokyo Hospital. Among them the RA and BIMA were used in 96 patients (78 males, 18 females; mean age, 63.2+/-6.7 years, group R), and the GEA and BIMA in 123 patients (101 males, 22 females; mean age, 61.0+/-11.6 years, group G). Their perioperative and follow-up data were studied. The preoperative risk factors were similar between the 2 groups, except that there were significantly fewer patients with renal dysfunction in group R. The surgical results did not differ between the 2 groups; however, the GEA was more commonly used for revascularization of the right coronary artery, while the RA was used for the diagonal, circumflex or right coronary arteries. Surgical mortality and morbidity rates were not significantly different. During the follow-up period of 2.3+/-1.6 years, the event-free rates as well as the survival rates were not significantly different. CABG with either the RA or the GEA in conjunction with the BIMA can be performed safely. The surgical results as well as the follow-up results were acceptable and no significant differences between the 2 groups were observed.     

乳内动脉─冠状动脉旁路移植术──68例外科技术探讨

本文报告６８例乳内动脉（ＩＭＡ）冠状动脉（冠脉）旁路移植术。手术均在中度低温体外循环下进行，心肌保护主要采用Ｓｔ．Ｔｈｏｍａｓ液经主动脉根部间断灌注，冠脉病变较重者加用冠状静脉窦持续逆灌。８例患者只用ＩＭＡ移植，６０例患者还同时用自体大隐静脉，应用左侧ＩＭＡ６６例，双侧ＩＭＡ２例，２例患者应用左侧ＩＭＡ作续贯式移植。ＩＭＡ与冠脉的吻合部位包括前降支６６例、对角支４例、右冠脉１例、回旋支１例。以冠脉吻合口计算，平均每例作２．８个吻合口。同期左室室壁瘤切除５例，冠脉内膜剥脱１４例。７例需安装主动脉内球囊反搏。术后３０天内死亡１例，手术死亡率１．４％，死亡原因为脑缺氧昏迷。手术存活的６７例中，６２例近期心绞痛症状消失，５例明显减轻；活动量均明显增加。远期结果有待进一步观察。结论：只要掌握好ＩＭＡ的游离和吻合技术，中国人应用ＩＭＡ作冠脉旁路移植术能取得满意的结果。     

A case of type IV dual left anterior descending artery associated with anomalous origin of the left circumflex artery in the presence of coronary atherosclerosis

Double origin of the left anterior descending coronary artery (LAD) from the left and right coronary arteries (type IV dual LAD) is a rare coronary anomaly. We report an unusual case of type IV dual LAD associated with anomalous origin of the left circumflex artery from the right coronary artery in a patient with a recent history of myocardial infarction. The first diagonal branch originating from the short LAD demonstrated 70-80% stenosis and the posterior descending artery was totally occluded. We believe that this unusual variance of the coronary arteries in association with atherosclerosis has not been previously reported.     

Five-year follow-up after long plaque-bridging coronary arteriotomy for diffuse coronary artery disease

Long arteriotomy bridging a stenotic plaque or segment may improve runoff in diffuse coronary artery disease. However, patency might be impaired due to vascular wall pathology. OBJECTIVE: To determine the patency rates of plaque-bridging arteriotomy compared to conventional coronary artery bypass grafting. METHODS: Between May 1995 and December 1998, 104 patients with a mean age of 65 +/- 7 years received a long arteriotomy extending over a heavily plaqued area in an effort to treat their diffuse coronary artery disease. The length of the arteriotomy ranged from 14 mm to 40 mm. We retrospectively analyzed the intra-individual bypass graft patency rates by multidetector-computed tomography or coronary angiography. RESULTS: The mean follow-up was 5 years. There were 5 (4.8 %) early and 10 (9.6 %) late deaths, three non-cardiovascular. Graft patency for internal thoracic artery (ITA) to left anterior descending artery (LAD) (plaque-bridging) was 94.8 %, for saphenous vein graft (SVG) to circumflex artery (CX) (plaque-bridging) 67 %, and SVG to right coronary artery (RCA) (plaque-bridging) 79.5 %. Graft patency for ITA to LAD (conventional) was 94.9 %, for SVG to CX (conventional) 72.4 %, and SVG to RCA (conventional) 75 %. Freedom from angina was 82.8 % (n = 58/70), freedom from myocardial infarction was 95.7 % (n = 67/70), freedom from reintervention was 91.4 % (n = 64/70) and freedom from reoperation was 100 % (n = 70/70). CONCLUSION: Diffuse coronary artery disease can be treated by extending the arteriotomy over the plaques, with graft patency rates comparable to bypass grafts onto less diseased segments.     

Mid-term results of conventional bypass surgery for complex proximal left anterior descending coronary artery stenoses.

BACKGROUND: The significant involvement of proximal left anterior descending (LAD) coronary artery affects patient prognosis and must be treated. Recently, as alternative methods to conventional coronary bypass (CABG), minimally invasive direct coronary artery bypass grafting (MIDCAB) and percutaneous transluminal coronary angioplasty with stent implantation (PTCA/S) have been proposed to reduce costs and patient discomfort. The aim of this study was to obtain early and medium-term results of CABG in patients with complex LAD disease in whom the expected results with PTCA/S or MIDCAB would have been suboptimal. METHODS: We retrospectively examined one hundred consecutive patients subjected to isolated CABG who received either a single graft to LAD or several grafts to LAD and diagonal branches. The choice of CABG was due to poor expectable results with PTCA/S or MIDCAB because of anatomical characteristics of the lesion, inclusion in ongoing randomized study comparing surgical versus non-surgical revascularization, or preference on the part of the cardiologist or patient. RESULTS: Left internal mammary artery (LIMA) was grafted to LAD in 99 (99%) patients; 65 (65%) patients received at least one saphenous graft to the diagonal branches. No death was observed within 30 days from the operation. One (1%) patient had a perioperative non-Q myocardial infarction (MI). At a mean follow-up time of 38 +/- 16 months (range 2-60), there were no cardiac deaths and no new MI. Six patients complained of recurrent angina: in all cases but one (vein graft failure to a diagonal branch), there were no clinical or diagnostic signs suggesting other graft failures. The probability of freedom from early and late events, including cardiac death, MI and recurrence of angina regardless of site, was 99% at 1 year and 86% at 5 years. CONCLUSIONS: At present, conventional CABG seems to be the "gold standard palliation" of LAD disease in most cases. It can be performed safely with excellent early and medium-term results in terms of freedom from cardiac events. Its comparison with percutaneous transluminal techniques and MIDCAB needs to be addressed in further prospective studies.     

Comparison of sequential left internal thoracic artery grafting and separate left internal thoracic artery and venous grafting

Objectives

The superiority of left internal thoracic artery (LITA) grafting to the left anterior descending artery (LAD) is well established. Patency rates of 80%–90% have been reported at 10-year follow-up. However, the superiority of sequential LITA grafting has not been proven. Our aim was to compare patency rates after sequential LITA grafting to a diagonal branch and the LAD with patency rates of LITA grafting to the LAD and separate vein grafting to a diagonal branch.

Methods

A total of 58 coronary artery bypass graft (CABG) patients, operated on between 01/2000 and 12/2002, underwent multi-slice computed tomography (MSCT) between 2006 and 2008. Of these patients, 29 had undergone sequential LITA grafting to a diagonal branch and to the LAD (“Sequential” Group), while in 29 the LAD and a diagonal branch were separately grafted with LITA and vein (“Separate” Group). Patencies of all anastomoses were investigated.

Results

Mean follow-up was 1958±208 days. The patency rate of the LAD anastomosis was 100% in the Sequential Group and 93% in the Separate Group (p=0.04). The patency rate of the diagonal branch anastomosis was 100% in the Sequential Group and 89% in the Separate Group (p=0.04). Mean intraoperative flow on LITA graft was not different between groups (69±8ml/min in the Sequential Group and 68±9ml/min in the Separate Group, p=n.s.).

Conclusion

Patency rates of both the LAD and the diagonal branch anastomoses were higher after sequential arterial grafting compared with separate arterial and venous grafting at 5-year follow-up. This indicates that, with regard to the antero-lateral wall of the left ventricle, there is an advantage to sequential arterial grafting compared with separate arterial and venous grafting.     

Creation of anastomoses between an extracardiac artery and the coronary circulation. Proof that myocardial angiogenesis occurs and can provide nutritional blood flow to the myocardium.

The purpose of this investigation was to determine whether blood vessels could develop de novo between an extracardiac artery and a collateral-dependent zone of the heart and to quantify the nutritive blood flow afforded by the new vessels. We also adapted the preparation so that angiogenically active agents could be chronically administered directly to the site of neovascularization in subsequent studies. To induce neovascularization between a systemic artery and the coronary circulation, the left internal mammary artery (IMA) was implanted in an intramyocardial tunnel in proximity to the left anterior descending coronary artery (LAD). A tube situated in the distal IMA connected to an implanted pump provided for continuous intra-arterial infusion at the site of angiogenesis. During the same procedure, an ameroid constrictor was placed on the proximal LAD, rendering its perfusion territory collateral dependent during a 2-3 week period. After 8 weeks, the functional capacity of the anastomoses established between the implanted IMA and the LAD territory was assessed by determining regional myocardial blood flow under basal conditions, during adenosine-induced vasodilatation, and during differential occlusions of the IMA and left circumflex coronary artery (LCCA). For all dogs, IMA occlusion decreased maximal LAD territory flow from 1.31 +/- 0.11 to 1.16 +/- 0.10 ml/min/g (p less than 0.005). Occlusion of the LCCA decreased LAD zone flow to 0.73 +/- 0.12 ml/min/g, whereas occlusion of the IMA in addition to the LCCA further decreased LAD zone flow to 0.42 +/- 0.11 ml/min/g (p less than 0.02). The IMA provided measurable nutritive blood flow in seven of 12 dogs, and in these dogs, the artery provided 30.0 +/- 2.5% of total LAD zone collateral conductance under conditions of maximal vasodilatation (range, 23-42%). We conclude that angiogenesis can occur between an implanted internal mammary artery and the native coronary circulation in dogs, providing modest nutritive blood flow to a collateral-dependent region. Further studies will be necessary to determine whether direct, local infusion of angiogenically active factors can enhance neovascularization and whether sufficient flow can be reliably supplied to make some variant of this approach clinically applicable.     

Noninvasive quantitative evaluation of the patency of internal mammary artery grafts to the left anterior descending coronary artery by transthoracic Doppler echocardiography

OBJECTIVES: Evaluation of left anterior descending coronary artery (LAD) flow by transthoracic Doppler echocardiography (TTDE) may allow assessment of anastomosis of the internal mammary artery (IMA) grafted to the LAD. This study tested the feasibility of TTDE to evaluate anastomotic stenosis of the IMA grafted to the LAD. METHODS: TTDE was performed in 66 patients (48 men and 18 women, mean age 67 +/- 10 years) with left or right IMA grafts to the LAD. The distal IMA flow at the anastomosis was visualized and the percentage stenosis was evaluated by the continuity equation using the anastomotic and pre-anastomotic flow velocity measured by TTDE as well as by angiography. If the anastomotic flow was not visualized by TTDE, the absence of augmented diastolic flow of the proximal IMA, by using the supraclavicular approach, with diastolic to systolic mean velocity ratio < 0.25 was considered as anastomotic occlusion. RESULTS: Anastomotic flow was visualized and the percentage stenosis was obtained by the continuity equation in 50 patients. In 4 of the remaining 16 patients, the proximal IMA flow by TTDE showed the occlusion pattern. In these 54 (82%) patients, the percentage stenosis by TTDE showed a significant correlation with that by angiography (r2 = 0.86, p < 0.0001). In all the remaining 12 patients with the patent proximal IMA pattern but without visualized anastomotic flow, the patency was confirmed by angiography. CONCLUSIONS: TTDE enables direct visualization and quantitative evaluation of the anastomotic patency in patients with IMA graft to the LAD.     

Determinants of coronary artery compliance in subjects with and without angiographic coronary artery disease

OBJECTIVES: The goal of this study was to determine factors contributing to the biomechanical properties of coronary arteries in people with and without angiographic coronary artery disease (CAD). BACKGROUND: The stiffness of the aorta is known to increase with increasing age and in the presence of CAD. However, little is known about the mechanics of coronary arteries, which may have important clinical consequences. METHODS: Intravascular ultrasound was used to determine the mechanical properties of coronary arteries and plaque behavior in subjects with CAD (n = 38), those with chest pain but angiographically normal coronary arteries (N) (n = 9) and those early (<2 weeks) after cardiac transplant (T) (n = 14). RESULTS: Coronary arteries dilated during systole in all groups, but cross-sectional compliance and distensibility were lowest in the proximal left anterior descending artery (LAD) in the subjects with CAD compared with the N and T groups (compliance: 1.2 +/- 0.2 vs. 1.7 +/- 0.5 and 2.7 +/- 0.6 x 10(-2) mm(2) mm Hg(-1) [mean +/- SEM] respectively, p < 0.02 CAD vs. T; distensibility: 0.8 +/- 0.2 vs. 1.7 +/- 0.5 and 1.7 +/- 0.3 x 10(-3) mm Hg(-1), p < 0.05 CAD vs. T). There was extensive plaque in the CAD group, and plaque was also present in the N group, but minimal atheroma was present in the T group. Plaque cross-sectional area diminished significantly during systole in both the LAD and circumflex arteries. Absolute changes were: 0.50 +/- 0.30, 0.33 +/- 0.11 and 0.68 +/- 0.13 mm(2) in the proximal LAD, distal LAD and proximal circumflex arteries, respectively. In subjects with atheroma, there was a significant correlation between cross-sectional compliance and plaque compression at all sites, and plaque compression was a significant determinant of cross-sectional compliance at both proximal sites in multiple regression analyses with age, mean arterial pressure and extent of plaque as the other independent variables. CONCLUSIONS: A major determinant of the systolic increase in coronary luminal area in patients with atheroma is a reduction in plaque cross-sectional area during systole.     

Myocardial perfusion scintigraphy with thallium-201 for prediction of graft patency early after internal mammary artery graft surgery

Myocardial perfusion scintigraphy with thallium-201 was performed in fifty-four patients after internal mammary artery (IMA) graft to the left descending coronary artery to determine the influence of the flow rate in the IMA on myocardial perfusion after the procedure. The flow rate in the IMA was 40 to 200 ml/minute (mean 103 +/- 26.6 ml/min). Myocardial perfusion after IMA surgery was good in 44 patients (82%). There was a correlation between IMA flow rate and surgical results. Only 53% of patients with IMA flow rates below 100 ml/min to atmosphere showed good myocardial perfusion.     

Left internal mammary artery grafting to left anterior descending coronary artery by minimally invasive direct coronary artery bypass approach

New surgical techniques for the treatment of the isolated lesion of the left anterior descending coronary artery (LAD) include off-pump surgery, minimal access to the heart, and endoscopic or computer enhanced coronary artery bypass surgery. The term minimally invasive direct coronary artery bypass surgery (MIDCAB) is related to a leftside minithoracotomy, the harvest of the left internal mammary artery (IMA) under direct vision, and an anastomosis performed between IMA and LAD under direct vision, using the technique of mechanical local immobilization by a special device. Alternative techniques include endoscopic harvesting of the IMA, or as a new and still experimental approach, the closed-chest total endoscopic coronary artery bypass grafting (TECAB) with the use of a high tech telemanipulator system. The currently reported results demonstrate the safety of MIDCAB surgery (30-day mortality < 0.5%, perioperative myocardial infarction < 2%, early patency rate between 95% and 98%). Mid-term results after 6 months have shown a patency rate between 94% and 97%, and more than 90% of the patients are without any angina symptoms. Due to this promising results MIDCAB is an alternative treatment for high-grade LAD lesions.     

Internal mammary artery steal syndrome secondary to an anomalous lateral branch

A 53-year-old male who underwent three-vessel coronary artery bypass grafting had a left internal mammary artery (LIMA) graft to the left anterior descending artery (LAD) and saphenous venous grafts to right coronary artery (RCA) and left circumflex coronary artery. Four years after surgery, he developed exertion angina associated with upper body exercises and even deep breathing at times. Angiographic evaluation revealed an anomalous lateral internal thoracic artery with steal phenomenon documented by adenosine cardiolyte. Patient was successfully treated with transcutaneous steel coil embolization by closing the anomalous vessel. Repeat stress electrocardiogram did not show any signs of ischemia. This case report emphasizes the variability in internal mammary artery (IMA) anatomy and the need to completely ligate all the branches of internal mammary artery intraoperatively.     

The possibility of non-invasive identification of occluded coronary artery in acute myocardial infarction. A comparison of ECG and echocardiography with coronary arteriography or autopsy

In 73 patients with acute occlusion of single coronary artery, the authors assessed the possibilities of ECG and echocardiography in determining non-invasively which of the 3 main arteries had been occluded. The sensitivity of ECG for the individual arteries and particular ECG signs ranged between 30-98%, the specificity was between 86-100%. While it was always possible to determine occlusion of the left anterior descending coronary artery (LAD), in several cases it was difficult to distinguish between occlusion of the left circumflex (LCX) and the right coronary artery (RCA). The LCX occlusion is a frequent source of error in interpreting electrocardiograms of patients with fresh myocardial infarction. The sensitivity of echocardiography in identifying the occluded coronary artery ranged between 77-100%, specificity 97-100%. The following ECG and echocardiographic signs of coronary occlusion were determined. The LAD occlusion is indicated by ECG changes in V1-4, and anteroseptal and apica asynergy on echocardiography. LCX occlusion: increased R wave amplitude in V1, and lateral and posterior wall asynergy. The RCA occlusion: ECG changes in II, III, aVF, asynergy of the posterior wall and part of the septum and right ventricle. These combined signs make possible the identification the occluded coronary artery in 95% of patients with myocardial infarction.     

Angioplasty induced myocardial ischaemia prolongs the signal-averaged P-wave duration in single vessel coronary artery disease.

Aims The P-wave duration (PWD) has been shown to prolong in conditions associated with elevated left ventricular end-diastolic and left atrial pressures, which also increase during transient coronary artery occlusions such as angioplasty. The aim of this study was to investigate the effects of angioplasty-induced myocardial ischaemia on signal averaged PWD in patients undergoing coronary angioplasty. Methods Eighty-four consecutive adult patients with single-vessel coronary artery disease undergoing elective coronary angioplasty were included. Duration of the P wave before and during coronary angioplasty were evaluated using signal averaged P-wave analysis. Patients were classified in groups according to the artery occluded, as left anterior descending (LAD) Group, right coronary artery (RCA) Group or Others Group (which included obtuse marginal, circumflex or diagonal). Results Patients included in the LAD, RCA and Others groups were similar with respect to clinical characteristics. The mean PWD at baseline was similar in all lesions (P>0.05), whereas mean PWD at inflation was significantly longer in LAD Group compared with RCA (126.1 +/- 9.5 ms vs 118.7 +/- 10.4 ms, P=0.007) and Others (126.1 +/- 9.5 ms vs 116.3 +/- 8.6 ms, P<0.001). The PWD during balloon inflation was significantly prolonged in all groups compared with baseline levels (LAD Group 126.1 +/- 9.6 ms vs 109.7 +/- 8.0 ms; RCA Group 118.7 +/- 10.4 ms vs 108.3 +/- 8.4 ms and Others Group 116.3 +/- 8.6 ms vs 109.7 +/- 6.0 ms, all P values <0.001). Conclusion Signal-averaged PWD significantly increases during single-vessel coronary angioplasty. This increase is more pronounced for LAD lesions. However, the clinical implications of P-wave prolongation during balloon angioplasty and the value of PWD as a measure of ischaemia remains to be clarified.     

术中即时桥血管流量测定在不停跳冠状动脉旁路移植术中的应用研究

目的:探讨术中即时血流测定(transit time flow measurement,TTFM)在不停跳冠状动脉旁路移植术中的应用价值。方法:2009年12月至2010年12月,对在北京安贞医院心外科行不停跳冠状动脉旁路移植术的427例患者,共计1 123支桥血管行术中即时血流测定,根据测定结果,定义满足以下3点标准中的2点者为桥血管失功能:1.搏动指数(PI)>5,2.左侧冠状动脉平均流量(mean graft flow,MGF)<10mL/min,右侧冠状动脉桥血管MGF<15mL/min,3.舒张期血流比例(diastolic flow,DF):左侧冠状动脉桥血管<50%,右侧冠状动脉桥血管<40%。对失功能的桥血管进行修正后再次测定血流量。结果:41例患者(41/427,9.6%)的47支桥血管(47/1 123,4.2%)诊断为失功能桥血管,修正的桥血管中13支为前降支桥血管,7支为对角支桥血管,15支为回旋支桥血管,11支为右侧冠状动脉桥血管。45支桥血管修正后流量满意,成功率为95.7%;2支桥血管修正后无明显改善。但术后6个月冠状动脉CTA检查示桥血管均通畅。结论:术中TTFM能便捷、有效地检测出由于吻合口狭窄导致的桥血管失功能,提高手术疗效,减少围术期不良心脏事件发生率。但对于冠状动脉远端血管床阻力较高的患者,其应用价值有待进一步观察。