Conduit selection and early graft failure in coronary artery bypass surgery: A post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting study

ObjectivesRelative rates of early graft failure and conduit selection in coronary artery bypass grafting (CABG) surgery remain controversial. Therefore, we sought to determine the incidence and determinants of graft failure of the left internal mammary artery (LIMA), radial artery, saphenous vein, and right internal mammary artery (RIMA) 1 year after CABG surgery.MethodsA post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) CABG study, involving patients from 83 centers in 22 countries. We completed an analysis of 3480 grafts from 1068 patients who underwent CABG surgery with complete computed tomography angiography data. The primary outcome was graft failure as diagnosed by computed tomography angiography 1 year after surgery.ResultsGraft failure occurred in 6.4% (68/1068) for LIMA, 9.9% (9/91) for radial artery, 10.4% (232/2239) for saphenous vein, and 26.8% (22/82) for RIMA grafts. The RIMA had a greater rate of graft failure (26.8%) than radial artery (9.9%) and veins (10.4%) (adjusted odds ratio, 2.69; 95% confidence interval, 1.30-5.57; P = .008 and adjusted odds ratio, 2.07; 95% confidence interval, 1.33-3.21; P = .001, respectively).ConclusionsIn this international trial dataset, LIMA and radial artery performed as expected, whereas vein grafts performed better. However, high rates of RIMA failure are worrisome and highlight the need for a thorough evaluation of the patency and safety of the RIMA in CABG surgery.     

Baseline flow in coronary bypass grafts

BACKGROUND: The purpose of the study is to estimate the total blood flow in coronary artery bypass grafts. METHODS: In a 3-year period 102 patients having a standardized coronary artery bypass grafting (CABG) with the left internal mammary artery (LIMA) anastomosed to the left anterior descending artery and a sequential vein grafted to the remaining diseased coronary arteries were included in the study, 21 females and 81 males. In females a mean of 3.9 anastomosis (range 2-5) were performed and in males a mean of 4.2 (range 2-6) were performed. Flow in the bypass grafts was measured with the transit-time method before termination of cardiopulmonary bypass. RESULTS: Females: LIMA 31 mL/min, vein graft 74 mL/min (26 mL/min per anastomosis), cumulated flow 105 mL/min. Males: LIMA 31 mL/min, vein graft 93 mL/min (29 mL/min per vein anastomosis), cumulated flow 124 mL/min. CONCLUSION: Conventional CABG may restore half of the normal resting coronary artery blood flow (250 mL/min).     

Endothelin receptors in endothelium-denuded human coronary artery bypass grafts and coronary arteries

BACKGROUND: Coronary artery bypass graft (CABG) surgery is hampered by deleterious vasospasm in the vessel wall, especially in vein grafts. Endothelin (ET) is a strong vasoconstrictor that can be observed in increasing concentrations during CABG surgery. METHODS: Endothelin-induced vasoconstriction was evaluated in isolated, endothelium-denuded vessel segments of the human saphenous vein (SV), left internal mammary artery (LIMA), and coronary arteries. The ET(A) and ET(B) receptor mRNA levels were quantified by real-time polymerase chain reaction (PCR) analysis. RESULTS: The ET(A) and ET(B) receptor mRNA levels were significantly higher in the SV than in the LIMA and the coronary arteries. ET-1 induced a more efficacious contraction in the SV and LIMA as compared with in the coronary arteries. The ET(B) receptor agonist, Sarafotoxin 6c (S6c) stimulated constriction of the LIMA and SV, while inactive in the coronary arteries. The concentration-response curve for S6c was biphasic, suggesting activation of ET(A) receptors at high concentrations as this response could be inhibited by FR139317 (10 micromol/L), and ET(B) at low concentrations as this response could be inhibited by BQ788 (0.1 micromol/L). CONCLUSIONS: Endothelin-induced vasoconstriction is mediated by ET(A) receptors alone in coronary arteries, while a combination of ET(A) and ET(B) receptors are of importance in SV and LIMA. Expression of contractile ET(B) receptors may be a pharmacologic disadvantage that contributes to the vasospasm during CABG surgery. The lower levels of ET(A) and ET(B) receptor mRNA in the LIMA and coronary arteries as compared with in the SV may provide one explanation for the better long- and short-term patency of LIMA as compared with SV grafts.     

Right internal mammary artery and radial artery composite in situ pedicle graft in coronary artery bypass grafting

Background. The use of two internal mammary artery grafts in coronary artery bypass grafting has been associated with decreased risks of death, reoperation, and angioplasty. However, bilateral internal mammary artery takedown is associated with higher incidence of sternal wound infection, particularly in people with diabetes and in elderly and obese patients. This study was conducted to explore the feasibility of using right internal mammary artery (RIMA) and radial artery (RA) as a composite graft while preserving the distal two thirds of the RIMA to leave the sternal blood supply intact.

Methods. Eighteen patients underwent coronary artery bypass grafting using proximal RIMA and RA composite graft as one of the bypass conduits. The distal two thirds of the RIMA was left intact to preserve sternal blood supply. The graft-free flows of the RIMA and RA composite graft and of the left internal mammary artery graft and the length of the composite graft had been measured. The graft patency and the flow in the distal part of the unharvested RIMA was evaluated postoperatively 2 weeks after the procedure. In 6 of these patients the graft patency was evaluated by selective angiography.

Results. There was no hospital mortality or incidence of perioperative myocardial infarction. None of the patients needed intraaortic balloon pump support postoperatively. There was no sternal wound infection. The vessels grafted were distal right coronary artery (n = 7), posterior descending artery (n = 8), obtuse marginal branches (n = 3), and posterolateral ventricular branch (n = 1); 1 patient received the composite graft as a sequential graft to the posterior descending artery and posterolateral left ventricular branches. The mean graft-free flow of the RIMA and RA composite graft was 98.06 ± 16.93 mL/min compared to left internal mammary artery flows of 55.80 ± 8.99 mL/min. All 16 patients who had a good echo window showed patent grafts when evaluated by two-dimensional echocardiography and color Doppler echocardiography. All of the 6 patients in whom the angiogram was repeated postoperatively showed patent RIMA and RA grafts.

Conclusions. Myocardial revascularization using proximal RIMA and RA in situ pedicle graft was safe in patients with diabetes and in obese and chronic obstructive pulmonary disease patients. This graft was useful to revascularize posterior descending artery, posterolateral ventricular branches of right coronary artery, and obtuse marginal branches where a left internal mammary artery and RA composite graft cannot be used because of technical reasons. Its usage was not associated with sternal wound infection.     

Off-pump coronary artery bypass grafting: comparison between standard CABG and off-pump CABG

We have performed 321 cases of coronary artery bypass grafting (CABG), between October 15 1995 and November 20 2000. We have evaluated the operative results of 142 cases (44.2%) of conventional CABG and 179 cases (55.8%) of off-pump CABG performed during this period. The average numbers of bypassed grafts was 3.53 for conventional CABG, and 1.62 for off-pump CABG. The total number of 369 grafts were anastomosed to 501 coronary arteries for conventional CABG, and 283 grafts were anastomosed to 290 coronary arteries for off-pump CABG. RESULTS: Although two saphenous veins were occluded, the early postoperative patency rate was 100% for conventional CABG using RITA, LITA, GEA and RA. Three site of stenosis in 18 LITAs and 2 in 16 RITAs were recognized in off-pump CABG without the use of stabilizers. One site of stenosis in 130 LITAs and 3 string signs in 44 GEA were recognized in off-pump CABG with the use of stabilizers. Postoperative angiography in 52 off-pump CABG cases at one year later showed no new lesion. CONCLUSION: The use of stabilizers and LIMA suture enables adaptation of the MIDCAB procedure to a wider range of coronary artery bypass procedures, and a higher graft patency can be expected.     

Experience of coronary artery bypass grafting with internal thoracic artery]

Between March 1990 and May 1991, twenty-nine patients underwent coronary artery bypass grafting. The mean number of grafts was 2.7 +/- 0.9 grafts per patient. 28 patients (96.6% of all cases) underwent CABG with the internal thoracic arteries. The perioperative mortality was 3.4% (1/29 cases). The postoperative coronary angiography at one month revealed that the early patency of total grafts, of internal thoracic artery grafts and of saphenous vein grafts were 96.7% (58/60 grafts), 100% (29/29 grafts), 93.5% (29/31 grafts) respectively. The early patency of internal thoracic artery graft was better than of saphenous vein graft.     

Failure of cryopreserved saphenous vein allografts following coronary artery bypass surgery.

Internal mammary arteries and saphenous vein grafts are the most satisfactory conduits for coronary artery bypass. However, at times these conduits are not available, due to previous use or poor quality. This paper reports our experience with 6 patients who underwent coronary artery bypass operations using 10 cryopreserved saphenous veins and internal mammary arteries. Postoperative graft patency was assessed with ultra fast computed tomography or cardiac catheterization. At operation, venous graft patency was 100% (10/10), at 1-8 weeks was 60% (6/10), and at 6-30 months was 0% (0/9). Alternately, all seven internal mammary artery grafts were patent at 2 to 18 months following surgery. One patient died 6 months following operation. Poor graft patency may be related to destruction of the cellular components or fibrosis resulting from the cryopreservation process or from immunologic factors. Because of poor patency compared to autologous conduits, we conclude the use of cryopreserved saphenous veins for coronary artery bypass should be severely restricted.     

冠状动脉旁路移植术的中远期效果随访

目的 分析冠状动脉旁路移植术(CABG)的中、远期疗效.方法 CABG术后行多层螺旋CT(MDCT)复查42例,行冠状动脉造影(SCA)复查59例;平均随访(66.79±44.27)个月.其中动脉旁路血管115支,静脉旁路血管195支.分别计算旁路血管的通畅率,比较其间的差异.结果 行MDCT复查者随访(53.93±36.80)个月,LIMA、RA、SV和CV的通畅率分别为94.7%、92.0%、85.9%和60.0%;有心绞痛再发组为83.5%,无心绞痛再发组为95.2%,差异有统计学意义.SCA复查者随访(75.95±47.09)个月,LIMA、RA、SV和CV的通畅率分别为87.1%、81.0%、53.6%和57.1%;有心绞痛再发组为62.0%,无心绞痛再发组为100.0%,差异有统计学意义.结论 MDCT可以作为一种无创检查方法来评价CABG术后旁路血管的通畅情况;动脉旁路血管的中、远期通畅率较静脉高;旁路血管病变是导致术后再发心绞痛的重要原因;旁路血管病变程度与CABG术后的随访时间密切相关.     

Total arterial myocardial revascularization using new composite graft techniques for internal mammary and/or radial arteries conduits

BACKGROUND: Total arterial myocardial revascularization (TAMR) is feasible because of the excellent long-term patency of the arterial conduits. We present five new surgical configurations for TAMR. METHODS: Between December 1998 and July 1999, 34 patients with triple vessel disease underwent TAMR. All patients were in CCS III or IV. Sketelonized internal mammary arteries (IMAs) were used. The surgical techniques for TAMR consisted of Y or T composite grafts constructed between the in situ RIMA and free LIMA graft or radial artery (RA) conduit in three different configurations. Other techniques uses included a T graft constructed between the RA conduit and free LIMA graft in two configurations. Twenty-six (76%) patients underwent contrast-enhanced TTE color Doppler before and after adenosine provocative test, and seven (20%) patients had postoperative coronary angiography. RESULTS: Overall, 144 anastomoses (average number per patient, 4.2) were completed. One (2.9%) patient undergoing an inverted T graft technique died on postoperative day 2. Another patient (2.9%) undergoing the right Y graft technique using IMAs and RA suffered perioperative AMI due to RA conduit vasospasm. Contrast-enhanced TTE color Doppler before and after the adenosine provocative test and at 1 week postoperation revealed a coronary flow reserve (CFR) of 2.1 +/- 0.2 in the LIMA stem, and in the RIMA stem, a CFR of 2.3 +/- 0.3 (P < 0.007). In one patient undergoing the right Y graft technique using IMAs, we found only anomalous flow dynamic parameters of RIMA, suggesting a partial graft closure. The angiographic examination revealed a free LIMA graft closure. At 6 +/- 2.4 months after operation 33 patients were alive and free of angina. The IMAs stem evaluation by TTE color Doppler at follow-up revealed a 2.45 +/- 0.1 mm LIMA diameter and 2.6 +/- 0.2 mm RIMA diameter, which was more than early postoperative data of P < 0.001 and P < 0.007, respectively. CONCLUSION: These data indicate that TAMR in young patients perhaps offers a better postoperative outcome and perhaps should be part of the surgical armamentarium. These techniques apply the "nontouch" principle and should be taken into consideration in patients with a heavily calcified aorta. Contrast-enhanced TTE color Doppler is a safe, accurate, and noninvasive test, which allows assessment of IMA patency and CFR evaluation. The flow reserve of the IMAs seems to be adequate for multiple coronary anastomoses.     

Patency of saphenous vein coronary artery bypass grafts from the vascular prosthesis of the ascending aorta.

BACKGROUND: Patients who have Stanford type A aortic dissection with impaired coronary arteries or who have aneurysms from the ascending aorta to the aortic arch with coronary artery disease need coronary artery bypass grafting (CABG) with tube graft replacement of the ascending aorta simultaneously. When vein grafts are used for CABG in these patients, the proximal anastomoses of vein grafts are attached to the prosthetic tube graft of the ascending aorta. However, the validity of proximal anastomoses of vein grafts to the prosthetic tube graft of the ascending aorta has not been confirmed. PATIENTS AND METHODS: We retrospectively analyzed patients who underwent venous coronary bypass grafting with prosthetic graft replacement of the ascending aorta. Between January 1984 and October 2002, 35 patients underwent CABG using saphenous vein grafts at the time of tube graft replacement of the ascending aorta, and the proximal anastomoses of the vein grafts were attached to the tube graft of the ascending aorta. Thirty-three venous bypass grafts were analyzed in 24 survivors. RESULTS: The postoperative catheterization showed only one early vein graft occlusion of 16 vein grafts anastomosed distally to the left anterior descending artery (LAD). All 14 venous grafts anastomosed to the right coronary artery (RCA) and 3 to the left circumflex artery (LCX) were patent. Therefore, the postoperative patency rate at discharge was 97.0% (32/33). Spiral computed tomography performed for long term follow-up revealed occlusion of two vein grafts (3.5 years and 9.7 years) anastomosed to the LAD. CONCLUSIONS: The patency rate of vein grafts anastomosed from prosthetic grafts of the ascending aorta to the native coronary arteries was similar to that of conventional CABG using saphenous vein grafts.     

非体外循环冠状动脉旁路移植术围手术期心肌梗死发生率与移植血管血流量的关系

目的探讨冠状动脉旁路移植术（CABG）中移植血管血流量与围手术期心肌梗死（MI）发生率之间的关系,为临床提供借鉴。方法采集2010年1～6月在北京大学第一医院连续58例因冠心病接受单纯择期非体外循环冠状动脉旁路移植术（（）PcAB）患者的临床资料。术中均采用左乳内动脉（I,IMA）吻合于左前降支（I．AD）,其他靶血管则以大隐静脉（SV）作为旁路移植血管,在关胸前循环状态稳定条件下,应用瞬时流量测定技术测量各移植血管的血流量,并计算移植血管总血流量。根据术后是否发生围手术期MI,将患者分成两组：MI组11例,其中男7例,女4例;年龄67．4±10．3岁;非MI组,47例,其中男38例,女9例;年龄63．3±9．9岁。分析两组患者术前及术中的相关危险因素。结果MI组与非MI组的手术时间差异无统计学意义（205．44±59．6rainVS．183．4±32．4min,t=1．69l,P=0．096）。MI组与非MI组移植血管数量（3．00±1．oo支VS．2．96±0．78支,t=0．154,P=0．878）、LIMA-LAD移植血管血流量（15．40±）1．37mi／minVS．16．50±10．83mJ／min,f=0．301,P=0．764）差异均无统计学意义;MI组与非MI组移植血管总血流量（41．03土19．50ml／minVS．64．09±32．44ml／min,t=2．254,P=0．028）差异有统计学意义。移植血管总血流量〈48．5ml／min为发生MI的危险因素EoR：4．706,95％CI（1．099,20．147）]。结论移植血管总血流量可在一定程度上预测CABG后急性心肌缺血事件的发生,总血流量〈48．5ml／min的患者术后发生围手术期MI的概率将明显增加。     

Graft patency in coronary bypass surgery.

A total of 514 vein bypass grafts and 49 internal mammary (IMA) grafts in 328 patients were studied after operation. Forty-two vein bypass grafts were performed without the use of a pump oxygenator, with a patency rate of 52%. When a pump oxygenator was used, the patency rate for vein bypass grafts was 78%. Patency rates for IMA grafts were 70% and 86%, respectively. In a small group of patients, endarterectomy with vein bypass grafts resulted in a patency rate of 59% in the right coronary artery, 88% in the left anterior descending coronary artery, and 74% in the circumflex artery. Except for the right coronary artery, these results compare favorably with those from vein bypass graft patency without endarterectomy. On the basis of these findings, insertion of bypass grafts into the coronary arteries without the use of a pump oxygenator cannot be recommended, unless the technique employed can be shown to produce graft patency rates comparable to those resulting from grafts done with the use of a pump oxygenator. Endarterectomy to the left anterior descending and circumflex arteries would not appear to affect vein bypass graft patency.     

The correlation between the intraoperative flow of coronary artery bypass grafts and the patency of grafts at midterm follow-up

We evaluated the correlation between the intraoperative flow of coronary artery bypass grafting (CABG) and the patency of grafts at midterm follow-up. When internal mammary arteries were used as grafts, there was no correlation between graft flow rate and graft patency rate. On the other hand, when saphenous vein was used, the greater graft flow was associated with better graft patency. Receiver operator characteristic( ROC) analysis identified the optimum threshold for the intraoperative flow rate to predict the patency at midterm follow-up as 23 ml/min (sensitivity 78%, specificity 71%). The difference in the correlation( of flow rate with patency rate) between the 2 graft types was attributed to the difference of physiological reaction of each type of grafts.     

Intraoperative flow measurements in gastroepiploic grafts using pulsed Doppler.

OBJECTIVE: The patency of a pedicled right gastroepiploic artery (RGEA) graft can be compromised by intraoperative twists, kinks or spasms. Therefore, a systematic flow assessment was made in RGEA grafts and was compared with similar measurements made in other types of bypass conduits. METHODS: Intraoperative pulsed Doppler flowmeter measurements obtained in a series of 556 consecutive patients undergoing at least one coronary bypass grafting onto the right coronary system were studied. Eighty-five RGEA grafts were compared with 1427 bypass grafts implanted in the same group of patients and consisted of the following conduits: 442 left internal mammary (LIMA), 149 right internal mammary (RIMA), 831 greater saphenous vein (GSV) and five inferior epigastric (EPIG) grafts. Sequential grafts were excluded from the analysis. RESULTS: Flow measurements and Doppler waveforms were abnormal and required graft repositioning, and the addition of a distal graft or intragraft papaverine injection (only in GSVs) in 29 cases (2.0% of all grafts). These graft corrections were necessary in 5.9% RGEAs, 3.4% LIMAs, 2.0% RIMAs, and 0.7% GSVs (P < 0.001). The relative risk for graft correction was eight times higher for RGEAs than for GSVs (P = 0.002). Flow increased from 8 +/- 2 to 54 +/- 5 ml/min (P < 0.0001). Flow data were significantly influenced by the type of run-off bed (P < 0.001), the measurements obtained in grafts implanted onto the right coronary artery and the left anterior descending artery being superior. Flows in RGEAs, however, were comparable with values obtained in other grafts implanted onto the same recipient coronary artery. CONCLUSIONS: A significantly higher incidence of graft malpositioning caused inadequate flows in RGEAs. However, normal flow values could be restored simply by assigning a better graft orientation under pulsed Doppler flowmeter control. Overall flow capacity of the RGEA did not differ from values obtained in other arterial and venous grafts implanted onto the same recipient arteries.     

Off-pump coronary artery bypass may decrease the patency of saphenous vein grafts

BACKGROUND: There is concern that a hypercoagulable status is caused after coronary artery bypass grafting without cardiopulmonary bypass (off-pump coronary artery bypass grafting, or OPCAB) and may potentially endanger the patency of the anastomosis. The aims of this study were: (1) to compare 1-year graft patency after OPCAB with that of conventional coronary artery bypass grafting (CABG) and that of on-pump beating CABG; and (2) to demonstrate any differences in patency of various conduits among the three groups. METHODS: We analyzed the results of 122 consecutive OPCAB cases (group 1) compared with those of 65 consecutive conventional CABG cases (group II) and those of 19 consecutive on-pump beating CABG cases (group III). In group I, coronary angiography (CAG) was performed immediately postoperatively and 1 year after surgery. In groups II and III, CAG was performed 1 year after surgery. Graft patency was graded as grade A (excellent), grade B (fair), or grade O (occluded). RESULTS: The average number of distal anastomoses in groups I, II, and III were 3.1 +/- 1.1, 3.7 +/- 0.9, and 3.6 +/- 0.9, respectively. In group I, postoperative CAG was performed in 92% of patients (112/122) before discharge. The patency rate (grade A + B) was 96.4% (162/168) for arterial grafts, and 85.6% (160/187) for saphenous vein grafts (SVG). One-year follow-up CAG was performed in 74% of patients (90/122). The patency rate was 97.8% (132/135) for arterial grafts and 67.9% (106/156) for SVG. In group II, 1-year follow-up CAG was performed in 65% of patients (42/65). The patency rate (grade A + B) was 93.5% (43/46) for arterial grafts and 88.3% (98/111) for SVG. In group III, 1-year follow-up CAG was performed in 89% of patients (17/19). The patency rate (grade A + B) was 100% (19/19) for arterial grafts and 86.8% (33/38) for SVG. CONCLUSIONS: Our results demonstrate that the patency rate ot SVG after OPCAB was significantly lower than that of arterial grafts in the early postoperative CAG (p < 0.001), and was also significantly lower than those of SVG of group II (p < 0.001) and group III (p < 0.01) in the postoperative 1-year CAG, although there was no significant difference in 1-year patency of arterial grafts among the three groups. Our data suggest that a specific perioperative anticoagulant therapy may be advisable in patients undergoing OPCAB with SVG.     

Impact of coronary artery bypass grafting on survival after aortic valve replacement

Treatment of coronary artery disease by coronary artery bypass grafting (CABG) concurrently with aortic valve replacement (AVR) improves outcome but survival compared to isolated AVR remains uncertain, as does the role of the left internal mammary artery (LIMA) graft to the left anterior descending (LAD) artery. All 799 patients undergoing elective primary AVR, using the St. Jude Medical mechanical prosthesis, with or without CABG, between March 1986 and May 2000, were reviewed with 100% follow-up. Operative mortality was 1.6% in 574 patients undergoing isolated AVR, 2.6% in 78 patients undergoing combined AVR and CABG with LIMA to LAD grafting (LIMA-AVR), 6.25% in 64 patients receiving vein grafts only to circumflex or right coronary artery territories (Non-LAD VG-AVR) and 2.4% in 83 patients receiving vein grafts to vessels including the LAD (LAD VG-AVR). Cox regression analysis showed improved survival after AVR compared to LAD VG-AVR (P=0.008), but with no significant difference to survival after LIMA-AVR (P=0.18) and Non-LAD VG-AVR (P=0.08). Multivariable regression analysis identified advanced age (P<0.001), male sex (P<0.001), absence of diabetes (P=0.02), number of grafts performed during surgery (P=0.04), non-congenital valvular pathology (P=0.001) and regurgitant valve disease (P=0.008) as independent predictors of reduced survival. LIMA-LAD grafting was not a significant variable in the multivariable model.     

Conditional probability of multiple coronary graft failure

To assess the potential capability of using artery-specific factors to predict the success of coronary bypass grafting, we classified each graft according to the type of graft (mammary, single vein, or multiple skip vein), the degree of obstruction in the native coronary artery, and the size of the grafted artery. The mean patency rates for each category of graft were determined by performing early postoperative (mean 6.6 months) arteriograms in 354 patients. We found that mammary arteries gave the best results for every graft category. Skip vein grafts had a higher mean patency rate than single vein grafts for arteries with obstructions between 70% and 90% and lumina less than 2.0 mm in diameter. The results for vein and skip grafts were equivalent for the category with arteries greater than 2.0 mm and obstruction greater than 90%. Vein grafts produced better results than skip grafts for the remaining categories. Patients were classified into subgroups according to the number of actually observed graft failures. The probabilities that specific numbers of grafts would fail were calculated for each patient. These probabilities were based upon the observed patency rates for the category appropriate for each graft and the hypothesis that individual grafts within a patient fail independently. We observed an excess number of patients with no failures or multiple failures than would be expected according to the hypothesis of independent failure and category-specific patency rates. Conversely, there were fewer patients than expected who had single failures. Therefore, we postulate that there may also be global factors which influence early graft patency.     

Mid-term angiographic results of radial artery (RA) graft in CABG: Does the proximal site of anastomosis affect graft patency?

Background Use of arterial conduits in coronary artery bypass grafting (CABG) is based on the documented excellent patency rates of left internal thoracic (mammary) artery (LITA). Alternative arterial conduits such as radial artery and gastroepiploic artery also showed superior long-term patency rates compared to vein grafts. Free arterial grafts are being used increasingly to replace the long saphenous vein as a conduit. This study was undertaken to compare two methods of radial artery grafting as a free graft and a composite graft. Methods Between January 1997 and October 2003 a total of 441 patients were operated for coronary artery bypass grafting using radial artery (RA) as one of the conduits. Among these patients, 125 patients received radial artery as a composite graft; In 68 patients RA was used with left internal thoracic artery as a composite y graft (n=68), and in 57 patients it was used with right internal thoracic artery (RITA) as an in situ composite pedicle graft (n=57). In the remaining 316 patients the radial artery was used as a free graft. Angiographic evaluation of radial artery graft was carried out in 63 patients who consented. Angiograms were carried out after an interval of 6–72 months (mean of 28.15±21.17 months). Of these 63 patients who underwent reangiography, the different surgical strategies used were RITA+RA composite in situ graft (n=34), LITA+RA composite y graft (n=17) and aorto coronary (free) RA graft (n=12). Results There were 3 hospital deaths in the series 441 patients. Among the 63 patients who underwent check angiography 60 patients were in NYHA C1 I and 3 patients were in C1 II. None of the patients had perioperative myocardial infarction. Angiographically overall radial artery graft patency rate was 94.1% (59 patients). In patients with RITA and RA in situ grafts patency rate was 94.1%, LITA+RA composite y graft patency was 94.1% and aorto coronary (free) radial artery grafts patency was 91.6%. Conclusion In 63 selected asymptomatic patients studied, we found that radial artery graft when used as an aortocoronary (free) graft or as a composite y graft with left internal thoracic artery or in situ pedicle graft with right internal thoracic artery the patency rates were comparable in all three groups.     

New Minimally Invasive Surgical Technique Using Arterial T-grafts for Treatment of Double-vessel Coronary Artery Disease: Experimental Study

Minimally invasive surgery has been used successfully in patients with single-vessel coronary artery disease (CAD), but there are no clinical reports of surgical techniques for the treatment of multivessel disease in this field using both internal mammary arteries (IMAs). Therefore a canine model has been established to demonstrate the feasibility of a minimally invasive surgical treatment of coronary artery double-vessel disease using both IMAs. Ten mongrel dogs underwent bilateral thoracoscopic preparation of both internal mammary arteries through small left lateral chest ports. Using the Port Access endovascular cardiopulmonary bypass system the right IMA (RIMA) was anastomosed as a free graft end-to-side to the left IMA (LIMA) as a T-graft. After induction of cardioplegic arrest the RIMA was anastomosed to the circumflex artery and the LIMA to the left anterior descending artery. All animals were weaned from cardiopulmonary bypass without inotropic support. The electrocardiogram showed sinus rhythm with no signs of ischemia. Intraoperative coronary angiography demonstrated patency of all anastomoses. The minimally invasive surgical treatment of double-vessel CAD using arterial T-grafts of both IMAs is thus feasible. Surgical trauma can be further reduced by harvesting the RIMA transmediastinally through the left lateral chest.     

Surgical revascularization of coronary bifurcations employing a single arterial graft according to the "omega-anastomosis" technique: initial experience

OBJECTIVES: The aim of this study was to evaluate the early postoperative outcome in patients undergoing "omega-anastomosis" construction, a technique that permits revascularization of coronary bifurcations employing a single arterial graft. MATERIALS AND METHODS: Between January 2000 and March 2002, omega-anastomosis was employed in 12 patients. The main indication for omega-anastomosis construction was the presence of a significant stenotic lesion involving one of the coronary tree's bifurcations, presenting a relevant secondary branch. There were ten men and two women, with a mean age of 55.4 +/- 4.3 years (range 48 to 66). The omega-anastomosis was constructed employing a single arterial graft (internal mammary artery or radial artery) effectively tailored to obtain a bi-petal shape and anastomosed to the coronary bifurcation according to a three-foliate anastomosis. All patients underwent postoperative coronary angiography. RESULTS: There were no hospital deaths, neither ECG nor enzymatic alterations. One patient was reoperated for excessive bleeding. The mean aortic cross-clamp time and duration of CPB (cardiopulmonary bypass) were 64 +/- 18 minutes (range 45 to 108) and 89 +/- 26 minutes (range 67 to 135), respectively. Thirty-four arterial conduits were used: 12 LIMA, 12 RIMA, and 10 RA. Twelve omega-anastomoses were constructed, in six patients employing the RA, and in six other patients employing one of the internal mammary arteries (IMAs). Five left Y-grafts between the in situ LIMA and free LIMA graft and one right Y-graft between the RIMA and RA were constructed. The mean ICU stay was 14.4 +/- 5.7 hours. The postoperative coronary angiography revealed a good patency of the "omega-anastomosis." Transthoracic color Doppler echocardiography (TTECD) demonstrated a normal IMAs flow pattern in all cases. CONCLUSIONS: We define the reported configuration as a possible surgical alternative to achieve total arterial myocardial revascularization in multi-vessels patients, associated with excellent postoperative outcome that should be part of the coronary surgical armamentarium.