Early vasoreactive profile of skeletonized versus pedicled internal thoracic artery grafts

BACKGROUND: No data are available on the early vasoreactive profile of skeletonized internal thoracic artery grafts. METHODS: Fifteen patients undergoing primary isolated coronary artery bypass grafting were randomly assigned to receive a skeletonized or pedicled internal thoracic artery graft. On the second postoperative day all patients were subjected to follow-up angiography and endovascular infusion of serotonin, acetylcholine, and isosorbide dinitrate. RESULTS: Internal thoracic artery grafts were widely patent in all cases. Mean diameters of the internal thoracic artery were 1.95 +/- 0.17 mm in the pedicled group and 2.26 +/- 0.40 mm in the skeletonized group. After serotonin challenge, mean internal thoracic artery diameters were reduced to 1.44 +/- 0.34 mm and 1.64 +/- 0.14 mm, respectively; acetylcholine challenge lead to a moderate degree of vasoconstriction (1.55 +/- 0.59 mm in the pedicled group and 1.84 +/- 0.15 mm in the skeletonized group). No statistically significant difference was evident between the two groups at any step. CONCLUSION: Skeletonization does not affect the early vasoreactive profile of internal thoracic artery grafts used for surgical myocardial revascularization.     

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.     

Long-term results of coronary artery bypass grafting: comparison of angiographic evaluation of internal thoracic artery and saphenous vein grafts

The long term (10 to 15 years) results of coronary artery bypass grafting (CABG) were studied in 20 patients. The duration of follow-up was ranged from 130 to 170 months with mean 146.4 months. Ten out of 20 patients underwent coronary angiography (CAG), which disclosed that the late patency of saphenous vein (SV) grafts was 68.8% (11/16), but 54.5% (6/11) of patent SV grafts showed atherosclerotic changes such as irregularity and localized narrowing. On the other hand, internal thoracic artery (ITA) grafts were all patent without any atherosclerotic luminal changes. We recognized that ITA grafts were superior to SV grafts from an angiographic standpoint of view in the long term in Japan.     

Bilateral internal thoracic artery grafting in diabetic patients: short-term and long-term results of a 515-patient series

BACKGROUND: Despite potential long-term benefits, bilateral internal thoracic artery grafting in diabetics remains controversial because of the risk of sternal infection. We sought to assess the short- and long-term outcome after left-sided bilateral internal thoracic artery grafting and to determine the configuration of choice in diabetic subsets. METHODS: Between 1996 and 2001, 515 diabetics underwent isolated left-sided skeletonized bilateral internal thoracic artery grafting. The outcome of 468 consecutive oral-treated diabetics and 47 selective insulin-treated patients was analyzed. Patients undergoing T-grafting were compared with those undergoing in situ bilateral internal thoracic artery arrangements. RESULTS: The respective rates for early mortality and sternal infections were 2.4% and 1.9% in oral-treated diabetics and 6.3% and 4.3% in insulin-treated diabetics. Multivariate correlates of sternal infection were chronic lung disease (odds ratio, 10), obesity (odds ratio, 7), reoperation (odds ratio, 22), and a creatinine level of 2 mg/dL or more (odds ratio, 8). Five-year survival was 82%. The T-graft (n = 437) and in situ (n = 162) subgroups had comparable baseline profiles. Freedom from cardiac mortality at 6.5 years was 95.6% and 87.6% (P =.277), and freedom from repeat revascularization was 91.5% and 92.7% (P =.860), respectively. The choice of bilateral internal thoracic artery configuration did not appear as a correlate of mortality, cardiac mortality, or major adverse cardiac events. Complementary right-sided gastroepiploic artery (hazard ratio, 0.36) and sequential (hazard ratio, 0.55) grafting were identified as protective factors against the occurrence of major adverse cardiac events. CONCLUSIONS: Routine skeletonized bilateral internal thoracic artery grafting can be implemented safely in oral-treated diabetics. This strategy is associated with a favorable late cardiac outcome and is thus recommended. Both left-sided bilateral internal thoracic artery configurations provide comparable short- and long-term outcomes.     

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.     

Failure of internal thoracic artery grafts: conclusions from coronary angiography mid-term follow-up

BACKGROUND: The objective of this study was to identify causes of the failures of internal thoracic artery bypass grafts according to operative technique, the internal thoracic artery used, and the coronary artery grafted. METHODS: This retrospective study concerns 302 follow-up angiographies performed in patients treated with 512 internal thoracic artery bypass grafts: 115 single grafts, 78 sequential grafts, and 109 grafts with two internal thoracic arteries (61 Y grafts). Postoperative angiography was performed after a mean period of 17.3 +/- 4.1 months. RESULTS: Failures consisted of 11 (2%) occluded grafts and 19 (4%) nonfunctioning grafts (threadlike internal thoracic artery). There was no difference in patency among the various types of left anterior descending artery bypass grafts anastomosed with the left internal thoracic artery. The failure rate was higher with the right internal thoracic artery (13%) than with the left internal thoracic artery (4%; p < 0.05). The failure rate of the left anterior descending artery bypass grafts (3%) was lower than that for the branches of circumflex artery bypass grafts (13%; p < 0.05). The 19 cases of nonfunctioning grafts did not include significant anastomotic stenosis: 14 were related to competitive blood flow, 4 to a poor recipient coronary arterial bed, and 1 to significant distal coronary stenosis. CONCLUSIONS: At least two thirds of failures of bypass grafts could have been avoided by more objective analysis of the coronary stenosis on preoperative coronary angiography and better mastery of the surgical technique.     

Immediate flow reserve of Y thoracic artery grafts: an intraoperative flowmetric study

OBJECTIVES: Use of both internal thoracic arteries in a Y graft configuration can raise concerns about the possibility of the single left internal thoracic artery being able to meet the flow requirements of two or three distal territories. We evaluated intraoperatively the flow reserve of a Y thoracic artery graft distally anastomosed to the anterior and lateral territories. METHODS: In 21 patients who had Y thoracic artery grafts, the flow was measured in the main stem of the left internal thoracic artery, in the left internal thoracic artery branch, and in the right internal thoracic artery. A transit time Doppler flowmeter was used. Measurements were repeated after the injection of a bolus of 20 mug/kg dobutamine. RESULTS: At baseline condition, the mean blood flow was 44.8 +/- 24.2, 23.4 +/- 11.5, and 21.4 +/- 15.3 mL/min in the main stem of the left internal thoracic artery, in the left internal thoracic artery branch, and in the right internal thoracic artery, respectively. After dobutamine injection, these values increased to 93.2 +/- 49.8, 46.1 +/- 22.6, and 42.5 +/- 31.2 mL/min, respectively. Flow reserve was 2.1 +/- 0.6, 2.2 +/- 0.9, and 2.1 +/- 0.9 mL/min, respectively. CONCLUSIONS: Intraoperative injection of dobutamine increases the flow in the Y thoracic graft by more than two times, not only in the main stem but also in each branch. This finding attests to the safety of Y thoracic conduits in terms of hemodynamic potential.     

Composite arterial Y graft has less coronary flow reserve than independent grafts

BACKGROUND: It is not known whether a composite Y graft of the left internal thoracic artery can provide sufficient blood flow to the whole left coronary system. The aim of this study was to compare regional myocardial blood flow (MBF) and coronary flow reserve after coronary artery bypass grafting using arterial composite Y graft or independent arterial grafts. METHODS: Positron emission tomography was performed at rest and after dipyridamole infusion using oxygen-15-labeled water 2 weeks after coronary artery bypass grafting. Regional MBF was calculated in seven segments of the left ventricle. Coronary flow reserve was defined as the ratio of MBF after dipyridamole infusion to MBF at rest. In the Y graft group (n = 22), a free arterial graft to obtuse marginal arteries was anastomosed to the proximal side of in situ left internal thoracic artery, which was anastomosed to the left anterior descending artery. In the independent graft group (n = 13), left anterior descending and obtuse marginal arteries were independently revascularized using in situ left internal thoracic artery and a free arterial graft. RESULTS: There was no difference between the groups in MBF at rest. Coronary flow reserve in the Y graft group was lower than that in the independent group in the anterobasal (1.43 +/- 0.07 versus 1.90 +/- 0.13, p = 0.038), apical (1.24 +/- 0.06 versus 1.64 +/- 0.12, p = 0.003), septal (1.34 +/- 0.05 versus 1.75 +/- 0.13, p = 0.023), and lateral regions (1.19 +/- 0.04 versus 1.66 +/- 0.09, p = 0.001). CONCLUSIONS: Although arterial composite Y graft improved MBF at rest, it was not as effective as independent grafts for improving coronary flow reserve soon after coronary artery bypass grafting.     

Assessment of an aortosaphenous vein graft anastomotic device in coronary surgery: clinical experience and early angiographic results

Background

Until now technologic evolution in coronary bypass surgery has focused on extracorporeal circulation, on operation without extracorporeal circulation, and on the exposure of the operative site. Recently a one-shot anastomotic device for the proximal anastomosis in coronary surgery was developed. We investigated whether the use of the aortic connector system (ACS) could facilitate the creation of aortosaphenous vein graft anastomoses in myocardial revascularization.

Methods

From November 2000, 40 ACS devices were used in 36 consecutive patients (mean age 70.7 ± 8.9 years); 12 patients (33.3%) underwent surgery on pump and 24 patients (66.6%) off pump; 50 distal anastomoses were performed. In all cases the connection with the ascending aorta was created before the distal anastomoses because of the necessity to slide the saphenous vein graft (SVG) over the vein transfer sheath. Intraoperative graft function was tested measuring blood flow by Doppler analysis. Postoperative evaluation of the anastomotic patency was carried out by early angiography in 34 patients (94.7%) but was excluded in 5 patients (5.3%) with extensive extracardiac vascular occlusive disease.

Results

Of 38 AC (95%) evaluated, 36 (94.7%) functioned properly. The end-to-side proximal anastomosis without aortic clamping is instantaneous, the quality of anastomoses was highly rated, no additional stitches were required, and all coronary arteries could be reached. Intraoperative quantity flow was measured by Doppler analysis and all but one showed good flow. Early postoperative angiography demonstrated good patency of the grafts in all cases but 2 (5.3%). At 1-year follow-up, 1 patient died of stroke; all other patients remained free of symptoms and no reoperation was required.

Conclusions

The use of ACS makes end-to-side anastomosis rapid, effective, and reproducible while eliminating aortic cross clamping; it opens a new era in beating or nonbeating coronary surgery. Long-term results are mandatory to confirm our favorable preliminary results.