Effect of coronary artery bypass grafting on native coronary artery stenosis. Comparison of internal thoracic artery and saphenous vein grafts

BACKGROUND: The purpose of this study was to investigate the influence of coronary artery bypass grafting on the degree of stenosis of the native coronary artery. METHODS: Experimental design: retrospective data analysis. Setting: University hospital. Patients: consecutive patients undergoing coronary artery bypass grafting (n=52). Bypasses using internal thoracic artery grafts (n=26) and saphenous vein grafts (n=37) to incompletely occluded coronary arteries were studied. Interventions: coronary artery bypass grafting using internal thoracic artery or saphenous vein grafts. Measures: stenosis of the native coronary artery on angiography. RESULTS: Three recipient coronary arteries bypassed with internal thoracic artery grafts (12%) and 14 recipient coronary arteries bypassed with saphenous vein grafts (38%) showed progression of narrowing (p=0.024). Two recipient coronary arteries bypassed with internal thoracic artery grafts (8%) and 13 recipient coronary arteries bypassed with saphenous vein grafts (35%) showed total occlusion (p=0.016). Hypertension, hyperlipidemia, diabetes mellitus, and smoking history did not correlate with progression of stenosis of the native coronary arteries. Graft flow measured during surgery in the saphenous vein grafts was not significantly different between the group that exhibited progression of the native stenosis and the group that did not. CONCLUSIONS: Coronary artery bypass grafting with saphenous vein grafts may result in progression of stenosis of the recipient coronary artery. This is less likely after coronary artery bypass grafting with internal thoracic artery grafts. This difference may be due to the ability of the pedicled internal thoracic artery graft to regulate flow. Thus competitive flow in the native coronary artery is minimized. This has significant clinical implications.     

Nonreversed saphenous vein grafts for coronary artery bypass grafting

Between August 1985 and December 1988, valvotomized saphenous vein grafts were used in 365 patients undergoing coronary artery bypass grafting (CABG). In this operation, the femoral end of the vein is attached to the aorta and the pedal end is attached to the coronary artery. Vein diameters measured 8 +/- 2 mm at the femoral end, 4.5 +/- 1.2 mm at the knee level, and 3.5 +/- 1.3 mm at the ankle. Ratios between levels were as follows: knee to femoral end, 0.56, and ankle to femoral end, 0.43. The ratio of knee to femoral end was 0.42 in cases with vein midthigh bifurcation. There were 1,310 grafts implanted (3.6 per patient). In 341 patients, CABG alone was performed, and 24 patients had combined procedures: 11 had CABG with mitral valve replacement, 9 had CABG with aortic valve replacement, 2 had CABG with repair of postinfarct ventricular septal defect, and 2 had CABG with automatic defibrillator implantation. Follow-up (up to 3.5 years) was attained in 97% of patients. For various reasons, 34 patients had a second angiogram between 3 and 41 months postoperatively. Of 120 vein grafts, 108 (90%) were patent. At autopsy, 11 patients with 45 vein grafts had 43 patent and clean grafts and two thrombosed. Use of nonreversed saphenous vein for coronary bypass is recommended. It assures a large proximal anastomosis, natural vein bifurcations can be used with fewer proximal anastomoses, better vein-coronary artery size matching is obtained, and the patency rate is satisfactory.     

Long-term clinical outcomes after coronary artery bypass grafting with pedicled saphenous vein grafts

Background

Coronary artery bypass grafting (CABG) using saphenous vein grafts (SVG) is vitiated by poor long-term patency of the vein grafts. Pedicled SVG harvested with the “no-touch” (NT) technique have demonstrated improved patency and could confer better outcomes. We aim to compare long-term results after CABG where NT or conventional technique was used for vein graft harvesting in a hypothesis-generating registry-based study.

Methods

Two propensity score matched cohorts (1349 patients) undergoing CABG with veins harvested with NT (NTT) or conventional (CT) technique in Sweden over the period 2005–2015 were used to compare long-term outcomes. Mortality, postoperative incidence of coronary angiography and need for reintervention was recorded and multivariable hazard ratios adjusted for risk factors were calculated.

Results

The mean follow-up time (SD) was 6.8 (3.3) years for NTT and 6.6 (3.2) years for CT. The adjusted hazard ratios for death, first angiography and need for reintervention for NTT patients were (95% CI) 0.97 (0.80–1.19), 0.76 (0.63–0.93), 0.91 (0.78–1.05), and 0.91 (0.71–1.17), respectively. Failed grafts were found in 43.2% of NTT patients and 53.6% of CT patients at angiography.

Conclusions

In this study NT grafting was associated with a lower risk for repeat angiography, however no difference could be observed for mortality and need for reintervention. The earlier reported improvements in patency of NT veins could possibly be reflected in an improved clinical outcome during the first 10?years after surgery.

     

Right coronary artery revascularization in patients undergoing bilateral internal thoracic artery grafting: comparison of the free internal thoracic artery with saphenous vein grafts

From April 1996 to July 1999, 241 consecutive patients underwent complete arterial revascularization with composite T-graft, including right coronary artery grafting with free right internal thoracic artery (ITA) (ITA group). They were compared with 127 bilateral ITA patients in whom saphenous vein grafts (SVG) was used for grafting the right coronary system (SVG group). The SVG group included more diabetics (40 vs. 29%), more emergency cases (21 vs. 12.4%), and the number of anastomoses per patient was higher (3.8 vs. 3.35, P=0.025). Thirty-day mortality was 3.9 and 4.1% in the SVG and the ITA groups, respectively (P=NS). Occurrence of perioperative complications (sternal infection, myocardial infarction, cerebrovascular accident, and bleeding) was not statistically significant. However, in sum, the complications rate was higher in the ITA group (8.3 vs. 2.4%, P=0.032). Midterm followup (2-56 months) showed increased return of angina in the ITA group (9.1 vs. 1.6%, P=0.00). However, 4-year survival (Kaplan-Meier) was comparable (91.7% in the SVG and 87% in the ITA group). In conclusion, early results of complete arterial revascularization with composite T-graft are similar to those of bilateral ITA grafting of the left and right system revascularization with SVG. However, lower return of angina in the SVG group makes SVG grafting preferable for the right coronary system.     

Single versus bilateral internal thoracic artery grafts with concomitant saphenous vein grafts for multivessel coronary artery bypass grafting: effects on mortality and event-free survival

BACKGROUND: The issue of superiority of single internal thoracic artery grafting versus bilateral internal thoracic artery grafting remains unresolved. The aim of this study was to compare the long-term outcome of single and bilateral internal thoracic artery grafting with concomitant saphenous vein grafting for multivessel coronary artery bypass grafting. METHODS: Between March 1985 and April 1995, 6650 patients underwent primary isolated coronary artery bypass grafting with internal thoracic artery grafts, including 4382 patients with multivessel bypass grafting requiring at least 3 grafts. Outcomes of patients undergoing single internal thoracic artery plus saphenous vein grafting (n = 2547) and bilateral internal thoracic artery plus saphenous vein grafting (n = 1835) were obtained at a mean follow-up of 11 +/- 3 years. RESULTS: Patients with bilateral internal thoracic artery grafting were younger, were mostly male, and had less diabetes, hypertension, unstable angina, and recent myocardial infarction than patients undergoing single internal thoracic artery grafting. Thirty-day mortality was 2.3% for the group undergoing single internal thoracic artery grafting versus 1.2% for those undergoing bilateral internal thoracic artery grafting (P =.007). Survival probability at 10 years was 88% for the single-graft group compared with 93% for the bilateral-graft group (P <.001). Multivariate analysis with propensity scoring showed that bilateral internal thoracic artery grafting decreased the risk of death (hazard ratio, 0.74; 95% confidence interval, 0.60-0.90), myocardial infarction (hazard ratio, 0.79; 95% confidence interval, 0.67-0.93), and coronary reoperation (hazard ratio, 0.41; 95% confidence interval, 0.21-0.80) throughout the follow-up period. Other significant predictors of death were diabetes, prior myocardial infarction, need for intra-aortic balloon pump, chronic heart failure, and peripheral vascular disease. CONCLUSION: Patients undergoing bilateral internal thoracic plus saphenous vein grafting appear to have a significantly better long-term clinical outcome than patients undergoing single internal thoracic artery plus saphenous vein grafting for multivessel coronary artery bypass grafting.     

Differences in adaptation to growth of children between internal thoracic artery and saphenous vein coronary bypass grafts

BACKGROUND: It is not known how the internal thoracic artery (ITA) and saphenous vein graft (SVG) adapts to somatic growth of pediatric patients who underwent coronary artery bypass grafting (CABG). METHODS: Twenty-two ITAs and 6 SVGs in 17 patients who underwent at least three postoperative catheterizations with biplanar cineangiography and followed for a minimum of 5 years were evaluated. We evaluated the length, diameter and curvature of the grafts by cineangiographies which were performed at 1 month, 1 year, 5 years and more than 5 years postoperatively. RESULTS: The length of the ITA (1-month: 117+/-31 mm, 1-year: 134+/-32 mm, 5-years: 146+/-28 mm, and >5-years: 155+/-34 mm, p=0.032) and diameter of the ITA (1.4+/-0.4 mm, 2.0+/-0.7 mm, 2.3+/-0.6 mm and 2.6+/-0.6 mm, p<0.0001) significantly increased over time, but neither the length nor diameter of the SVG length: 121+/-33 mm, 119+/-29 mm, 119+/-25 mm and 126+/-1 mm, p=0.9907; diameter: 4.1+/-1.0 mm, 3.9+/-0.7 mm, 4.0+/-0.8 mm and 3.3+/-0.4 mm, p=0.5784) increased. Although the ITA exhibited no change in curvature over time (1 month: 1.15+/-0.07, late: 1.15+/-0.07, p=0.8490), the curvature of the SVG significantly decreased over time (1 month: 1.42+/-0.19 and late: 1.25+/-0.16, p=0.0277). The percent segmental length of ITAs were changed little from early to late after CABG (1 month: proximal: 33.7+/-7.0%, middle: 33.3+/-7.9% and distal: 32.9+/-7.9%, vs late: 34.3+/-7.2%, 33.2+/-7.9% and 32.5+/-7.9%, p=0.937). CONCLUSIONS: ITAs grow in proportion to somatic growth, while SVGs course in a more linear fashion in adapting to patient growth.     

Functional assessment of disease-free saphenous vein grafts at redo coronary artery bypass grafting

BACKGROUND: Reoperations for coronary artery bypass grafting are on the rise. The general rule of replacing all saphenous vein grafts (SVGs) older than 5 years of age at the time of reoperation has recently been challenged on clinical grounds. This study provides functional data of endothelial behavior in long-term vein grafts. METHODS: Previously placed SVGs were removed at the time of redo operations. Nitric oxide (NO) measurements in real time were carried out before and after stimulation with morphine. The measurements were compared to the angiographic appearance of the grafts obtained prior to operation. Grafts were categorized into 3 groups: disease-free, moderately diseased, and severely diseased. RESULTS: Sixteen grafts were analyzed. Five were angiographically disease-free, 4 had moderate, and 7 severe disease. In the disease-free group, peak NO production after 10(-6) mol/L morphine stimulation was 35 mol/L, equivalent to the production of native saphenous vein. The severely diseased group did not demonstrate an increase in NO production, and the moderately diseased group produced a small rise in production. CONCLUSIONS: Measurement of NO release of old SVGs, when angiographically pristine, equals that of native saphenous vein. These findings support the recent clinical observations that long-term angiographically disease-free vein grafts are biologically privileged.     

Patency of sequential and individual saphenous vein grafts after off-pump coronary artery bypass grafting

Abstract Background: The impact of the grafting techniques (individual or sequential grafts) on the graft patency of off‐pump coronary artery bypass grafting (OPCAB) has not been reported. The mid‐term patency rates for individual and sequential saphenous vein grafts (SVGs) as coronary bypass conduits of OPCAB were compared. Methods: A total of 714 distal coronary anastomoses on 448 SVGs were assessed using a 64‐multislice computed tomography in 398 patients at an average of 26.4 ± 23.6 months (three months to five years) after an OPCAB procedure. The blood flow of grafts in the proximal segment of individual and sequential SVGs was also compared. Results: The overall patency of sequential SVGs (95.9%) was significantly superior to individual ones (90.6%, p = 0.022). The anastomoses on the sequential conduits had better patency (95.1% vs. 90.1%, p = 0.013). The patency of side‐to‐side anastomoses (97%) was better than that of end‐to‐side anastomoses (93.1%) and also better than that of the individual end‐to‐side anastomoses (90.1%, p = 0.002, p = 0.041). No significant difference was observed between the two approaches in regard to the three major coronary systems; however, anastomoses on sequential grafts had superior patency to those on individual grafts in the right coronary system (p = 0.008). The blood flows of double and triple sequential SVGs were significantly higher than those of individual ones (p < 0.001, p = 0.048, respectively). Conclusions: The mid‐term patency of a sequential SVG conduit after OPCAB is excellent and generally superior to that of an individual one. (J Card Surg 2010;25:633‐637)     

电视内镜下获取大隐静脉在冠状动脉旁路移植术中的应用

目的 探讨冠状动脉旁路移植术(CABG)中应用微创电视内镜下获取大隐静脉的手术要点和临床效果.方法 自2001年1月至2008年12月212例患者接受CABG,按照获取大隐静脉的方法分为两组:内镜组72例,传统组140例.比较分析两组患者的手术资料和术后并发症等情况.结果 内镜组获取静脉的时间与传统组比较差异无统计学意...     

Flow dynamics in internal thoracic artery grafts 10 years after coronary artery bypass grafting

BACKGROUND: Flow dynamics in internal thoracic artery grafts 10 years after surgery are not known. METHODS: Doppler examination was performed in native internal thoracic arteries as a control (n = 8) and in internal thoracic artery grafts to the left anterior descending coronary artery 6 months postoperatively (group A, n = 25), at 5 years (group B, n = 14), and at 10 years (group C, n = 11). RESULTS: Each graft group showed a diastolic to systolic peak velocity ratio of less than 1.0 at the proximal end, and more than 1.0 at the distal end, but the control group showed a ratio of less than 1.0 throughout the length of the artery. The diastolic peak velocity of the graft groups was significantly faster than that of the control group at the distal end (versus group A, p < 0.01; versus group B, p < 0.005; and versus group C, p < 0.05). The systolic peak velocity of the graft groups was significantly lower than that of the control at the proximal end (versus group A, p < 0.0001; versus group B, p < 0.005; and versus group C, p < 0.0005). There were no significant differences of flow velocities among the graft groups and graft diameter among the four groups. CONCLUSIONS: Although the internal thoracic artery is systolic predominant, when native artery is used as graft, it changes its hemodynamics to diastolic predominance, especially at the distal end. Even after 10 years, graft flow dynamics are unchanged. This hemodynamic character may be one of the factors related to the superior long-term patency.     

Long-term angiographic evaluation of free internal thoracic artery grafting for myocardial revascularization.

Between 1990 and 1998, 41 patients underwent free internal thoracic artery grafting for coronary artery bypass. To investigate usefulness of free internal thoracic artery grafting, we compared the postoperative graft patency of free internal thoracic artery grafts with that of in situ internal thoracic artery grafts, and compared the long-term results such as actual survival and cardiac-event free rate in patients receiving free internal thoracic artery grafts with those results in patients receiving in situ internal thoracic artery grafts. Postoperative changes in luminal diameter of free internal thoracic artery grafts were calculated as the difference between the first and secondary angiographic evaluation in 17 patients who were followed-up for more than 5 years. The early postoperative graft patency rate of free internal thoracic artery was 95.2%. All these early patent grafts remained patent at the time of the late study. At 9 years post-surgery, patients who received free internal thoracic artery grafts had a survival rate of 100% and a cardiac event-free rate of 77.5%; the luminal diameter enlargement was 0.57 mm, and the mean matching rate increased 27.8%. We conclude that the free internal thoracic artery provides long-term results comparable with those of in situ internal thoracic artery.     

Long-term results of bilateral internal thoracic artery grafting

Background. Little is known about the long-term results of the uniform group of patients who had bilateral internal thoracic artery (ITA) grafting with the method of left ITA-to-left anterior descending coronary artery and right ITA-to-circumflex artery.

Methods. Late follow-up study was performed in the first consecutive 203 patients (mean age, 62.6 ± 9.1 years) who underwent isolated coronary artery bypass grafting with the left ITA anastomosed to the left anterior descending coronary artery and the right ITA to major branches of the circumflex artery. The patients were grouped according to the patency of ITA grafts demonstrated by early postoperative angiography (Both patent (BP) group, 168 patients: both ITAs showed complete patency; Not patent (NP) group, 23 patients: at least one ITA was dysfunctional).

Results. Actuarial 7-year survival in all patients was 89.3% ± 3.1%. The cumulative probability of event-free survival for cardiac death, myocardial infarction, intervention, and angina at 7 years was 96.6% ± 1.8%, 98.0% ± 1.5%, 86.7% ± 3.2%, and 90.7% ± 2.9%, respectively. NP group had more myocardial infarction and angina than the BP group, but was not statistically significant. Because of failed grafts at the early angiography, intervention was performed more frequently in NP group (p < 0.01).

Conclusions. Our results of actuarial 7-year survival and the cumulative probability of event-free survival were at least comparable to the results of other similar studies using bilateral ITA. The freedom from angina appeared to be better than in the previous study. Overall our study supports the continued use of this method of ITA grafting.     

Long-term (5 to 12 years) serial studies of internal mammary artery and saphenous vein coronary bypass grafts

Serial arteriograms were obtained in 501 patients after coronary bypass grafting. Study I within 5 years of operation (mean interval 15 months) and Study II more than 5 years after (mean interval 88 months, range 60 to 147 months). One hundred patients received both internal mammary artery and saphenous vein grafts: 37, mammary artery grafts only, and 364, vein grafts only. In Study I, 645 (82%) of 786 vein grafts were patent, 42 (5%) stenotic or irregular, and 99 (13%) occluded. Of 140 mammary artery grafts, 136 (97%) were patent, two (2%) stenotic, and two (2%) occluded. Of the 645 vein grafts patent in Study I, 357 (55%) remained patent in Study II, 119 (18%) were stenotic or irregular, and 169 (26%) were occluded. Of 136 mammary artery grafts patent in Study I, 130 (96%) were unchanged, one was stenotic, and five (4%) were occluded in Study II. Early vein graft patency was influenced by the coronary artery grafted and by angina. Progression of vein grafts patent at Study I to stenosis or occlusion at Study II was associated with increasing postoperative interval (p less than 0.00001), interval myocardial infarction (p less than 0.001), angina (p less than 0.001), diabetes (p less than 0.004), hypercholesterolemia (p less than 0.006), and hypertriglyceridemia (p less than 0.02); it was not influenced by the coronary artery grafted. Within 5 years of operation, mammary artery graft patency exceeded vein graft patency. Between 5 and 12 years after operation, the attrition rate of vein grafts greatly exceeded that of mammary artery grafts (p less than 0.0001).     

Long-term results with aorta-to-coronary artery bypass vein grafts

From our experience with more than 500 patients treated with aorta-to-coronary artery bypass vein grafts, follow-up of the first 350 patients for a period of from 6 to 43 months is analyzed. The group had 82% good results, 4% failures, 10% operative deaths, 3% late deaths, and 1% late deaths not related to the graft. Preoperative and operative factors are correlated with early and late results. The number of late deaths has not increased with the passage of time, although a distinct, moderate degradation in the quality of results in the living patients is seen. The presence of prior infarction, significant functional myocardial impairment, or extensive involvement of the coronary arterial tree tends to diminish the quality of results in survivors and to be associated with both degradation of the quality of results with the passage of time and the occurrence of late deaths.     

Off-pump coronary artery bypass grafting: long term angiographic results

OBJECTIVE: Although short-term results of off-pump coronary artery bypass grafting are well documented, late postoperative data are still scarce. This report provides an analysis of late postoperative control angiograms. METHODS: 265 patients (231 males, 34 females; mean age: 54 +/- 10) underwent postoperative angiographic control, after an average postoperative period of 4.2 +/- 2.3 years (up to 9 years, a total of 1110 years). A total of 385 distal anastomoses on 258 internal mammary arteries (IMAs) and 127 saphenous vein grafts (SVGs) were evaluated. The primary operation was single bypass in 156 cases (62%), double bypass in 98 (34%), and triple or more bypass in 11 (4%). RESULTS: Out of 258 IMAs, 241 were patent (93%), while SVG patency was 65% with 82 patent grafts out of 127 (p < 0.0001). The patency in the lateral branches (62%) and right coronary system (64%) were similar. The variables associated with graft occlusion were hypercholesterolemia (p = 0.02), poor left ventricular performance (p = 0.03), reoperation (p = 0.01), target coronary vessel caliber less than 1.5 mm (p < 0.0001), poor native coronary vessel quality (p = 0.0003) and low-grade stenosis (p = 0.02). In the poor left ventricle group, the left ventricular segmental wall motion score was improved (p = 0.004). Consequently, 47 patients underwent secondary revascularization (35 PTCA and 12 CABG). The leading indication was native coronary artery disease progression, frequently in the circumflex system, followed by graft failure. The cases with native vessel disease progression were referred to PTCA/stenting, while those with LAD graft occlusion were treated surgically. CONCLUSIONS: Probably the best candidates for OPCAB are those having target vessels of good caliber and quality, and high-grade stenoses. Postoperative lipid-lowering therapy seems to be prudential.     

Long-term fate of the internal mammary artery and saphenous vein grafts

Thirty-four patients, each receiving internal mammary artery (IMAG) as well as saphenous vein grafts (SVGs), returned with symptoms 3 to 12 years after operation and underwent angiographic studies. At a mean follow-up period of 6.8 years, two (6%) IMAGs were occluded and 33 (94%) were in excellent condition. Of the 57 SVGs, 28 (48%) were totally occluded, 12 (22%) had severe atherosclerosis, and only 17 (30%) were in good condition. Seven patients (20%) had new significant lesions in the ungrafted coronary arteries. Failure of SVGs was the predominant cause of symptoms in this group of patients. Late failure of the SVGs appears to be due to progressive atherosclerosis in the grafts. The IMAGs tend to remain free from atherosclerosis and perform much better than the SVGs in the long run.     

A quantitative angiographic study of characteristics of internal thoracic artery grafts in coronary artery bypass surgery

In adult patients with atherosclerotic coronary artery disease and in pediatric patients with Kawasaki heart disease, characteristics of internal thoracic artery grafts (ITA grafts) used for coronary artery bypass grafting (CABG) were quantitatively assessed by postoperative angiography. In 142 adult patients with a ITA graft for the left anterior descending artery (LAD), the diameter ratio between ITA graft and recipient LAD at the point close to the anastomotic site (ITA/LAD diameter ratio) was determined by postoperative angiography. This ratio for the adult patients as a whole was 1.04 +/- 0.34. The multivariate analysis (Quantification I) was performed to assess the effects of the following 12 factors on the ITA/LAD diameter ratio: (1) age at the time of operation, (2) sex, (3) time-duration from the operation to angiography, (4) laterality of the ITA used, (5) presence of an undivided major side branch of the ITA graft, (6) presence of blood flow competition between the ITA graft and other grafts, (7) presence of distal stenosis of the recipient LAD, (8) severity of LAD stenosis after the operation, and (9-12) presence of hyperlipidemia, diabetes mellitus, hypertension, or smoking history. The standardized category scores of 25% LAD stenosis, 50% LAD stenosis, and blood flow competition between the ITA and other grafts were -0.815, -0.359, and -0.306, respectively. Insignificant stenosis of the recipient coronary artery was associated with reduction of the ITA/LAD diameter ratio, and this ratio strongly correlated with the severity of LAD stenosis (partial correlation coefficient: 0.627). However, no other factors significantly influenced on the ITA/LAD diameter ratio. In 15 pediatric patients, the length and diameter of 19 ITA grafts and 5 saphenous vein grafts (SVGs) which remained patent in the early (about one month) and late (14 +/- 4 months) postoperative period were determined. Only in the ITA graft, increases in graft length and diameter associated with patient growth were recognized. In the present study, the physiological characteristics of the ITA graft were demonstrated as a viable conduit with flow adaptability and growth potential.     

Bilateral internal thoracic artery grafting: long-term clinical and angiographic results of in situ versus Y grafts

BACKGROUND: We evaluated whether bilateral internal thoracic arteries provide the same long-term results when used as in situ grafts and as Y grafts.Methods and Results: From October 1991 to February 2000, 1818 patients had bilateral internal thoracic arteries used as in situ (n = 1378, group A) or as Y grafts (n = 440, group B). The number of anastomoses per patient and the number of bilateral internal thoracic artery anastomoses per patient were higher in group B (3.1 +/- 0.9 and 2.7 +/- 0.9) than in group A (2.9 +/- 0.8 and 2.2 +/- 0.6) (both P <.001). The number of right internal thoracic artery anastomoses per patient rose from 1.0 +/- 0. 3 in group A to 1.4 +/- 0.6 in group B (P <.001), and the number of sequential anastomoses per right internal thoracic artery graft rose from 4.1% to 34.3% (P <.001). Thirty-day mortality was 2.0% in group A versus 2.5% in group B (P = not significant). No difference in postoperative course was detected. Eight-year survivals were 95.8% +/- 2.7% in group A versus 94.8% +/- 4.0% in group B (P = not significant), and event-free survivals were 95.2% +/- 2.9% in group A versus 93.6% +/- 4.4% in group B (P = not significant). Early angiograms were obtained in 295 patients (945 anastomoses, 863 distal and 82 proximal Y grafts), 213 patients (611) in group A and 82 patients (334) in group B. Patency rate was 98.8% in group A and 96.0% in group B (P = not significant), whereas grade A patency rate was 97.2% in group A and 96.4% in group B (P = not significant). Late angiograms were obtained in 88 patients (25 in group A and 63 in group B) at a mean of 17.5 +/- 18.4 months: patency rate was 100% in group A and 99.2 in group B (P = not significant), and grade A patency rate was 98.6% in group A and 98.8% in group B (P = not significant). No Y anastomosis was occluded or stenosed. COMMENT: Survival, incidence of cardiac events, and angiographic patency in the early and late phases are similar for bilateral internal thoracic arteries used either in situ or as Y grafts. However, Y grafting with bilateral internal thoracic arteries increases the number of anastomoses per bilateral thoracic artery, as well as the flexibility of the right internal thoracic artery.