Atherosclerotic involvement of the radial artery in patients with coronary artery disease and its relation with midterm radial artery graft patency and endothelial function

BACKGROUND: The radial artery has recently been proposed as an alternative arterial conduit for surgical myocardial revascularization. This study was conceived to evaluate the degree of atherosclerotic involvement of the radial artery in patients with coronary artery disease and the eventual influence of a subtle degree of preoperative atherosclerosis on the midterm results of radial artery grafts. METHODS AND RESULTS: The intima-media thickness of the radial artery, common carotid artery, and internal thoracic artery was evaluated in 42 coronary artery disease patients and in 26 control patients. All radial arteries were then used for myocardial revascularization; 30 patients submitted to control angiography after 5 years. The mean intima-media thickness was 0.92 +/- 0.22 mm for the common carotid artery, 0.54 +/- 0.16 mm for the internal thoracic artery, 0.55 +/- 0.11 mm for the radial artery in coronary artery disease patients versus 0.79 +/- 0.14 mm, 0.52 +/- 0.11 mm, and 0.56 +/- 0.09 mm, respectively, in control patients (P =.001 only for the common carotid artery). No correlation was found between the intima-media thickness of the carotid, internal thoracic, and radial artery. No correlation was found between the preoperative intima-media thickness of the radial artery and the midterm patency and endothelial-mediated vasodilating capacity of radial artery grafts. CONCLUSION: In coronary artery disease patients, radial artery atherosclerotic involvement is more frequent than that of the gold standard internal thoracic artery but still by far less severe than that of the common carotid artery. The early atherosclerotic signs often observed in the radial artery do not seem to have the potential to influence radial artery graft patency and endothelial function.     

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.     

Effect of ascorbic acid on endothelium-dependent vasodilatation of human arterial conduits for coronary artery bypass grafting.

OBJECTIVE: Techniques aimed at improving the performance of arterial conduits will maximize the clinical benefit achievable with coronary artery bypass surgery. Controlling oxidant stress could be a strategy for preventing early graft deterioration. We tested the effect of a free radical scavenger, ascorbic acid (vitamin C), on preserving the endothelium-dependent vasodilatation function in vitro of radial artery and internal thoracic artery. We also tested its effect on the amount of reactive oxygen species (ROS) generated by each graft. METHODS: Radial artery (RA, n=25) and internal thoracic (ITA, n=19) segments were obtained from coronary artery bypass grafting patients. Each segment was divided into 3-4 mm vascular rings and incubated with or without ascorbic acid (10(-3) mol/l) for 1 h or 72 h. Using the organ bath technique, the endothelium-dependent vasodilatation function was tested in vitro by the addition of cumulative concentrations of acetylcholine (10(-9)-10(-5) mol/l) following vasocontraction by endothelin-1 (3 x 10(-8) mol/l). ROS were measured by using chemiluminescence technique at 1-h and after 72 h incubation with or without ascorbic acid. RESULTS: There were no differences in the vasodilatation function between control and ascorbic acid group of both arteries in the 1-hour incubation experiment. However, in the 72 h incubation experiment, ascorbic acid preserved the endothelium-dependent vasodilatation function of RA compared with control group (35.8+/-2.2% vs. 25.9+/-2.1%; P=0.005), but not ITA (39+/-3.5% vs. 40.5+/-9.3%; P=0.438). After 72 h incubation, RA generated significantly more free radicals compared with 1 h (133.7+/-151.5 vs. 16.8+/-16.8 cps/mg x 100; P=0.01); however, AA has no statistically significant effect on decreasing the amount of free radicals generated by both arteries. CONCLUSIONS: In RA, ascorbic acid is able to preserve the endothelium-dependent vasodilatation function after 72 h incubation, but not after 1 h. However, the mechanism of action of AA is not completely understood. This finding could open the door for understanding the role of oxidant stress and antioxidants in preserving the endothelial function of coronary artery bypass grafts.     

Production of endothelium-dependent relaxation responses by saphenous vein grafts in the canine arterial circulation

To determine if venous endothelium can acquire the ability to elicit endothelium-dependent relaxation responses, five dogs underwent femoral artery bypass with autogenous saphenous vein. The veins were harvested 15 to 17 months later. Endothelium-dependent relaxation was determined by measuring tension of deendothelialized coronary arteries mounted on a tensiometer and superfused with the effluent of the vein grafts. These grafts were perfused with acetylcholine and calcium ionophore A23187, which cause case vascular smooth muscle relaxation by means of endothelium-dependent relaxing factor production. Control arteries and veins were obtained from other dogs for comparison. In response to acetylcholine from 10(-9) to 10(-4) mol/L, the final cumulative relaxation produced in the detector coronary artery (mean +/- SD) was 64.2% +/- 25.7% by the control arteries, 14.2% +/- 5.5% by the vein bypass graft, and 5.3% +/- 5.6% by the control veins. In response to A23187 from 10(-8) to 10(-4) mol/L, the final cumulative relaxation was 66.2% +/- 19.0% by the control arteries, 30.6% +/- 8.9% by the vein bypass grafts, and 5.3% +/- 5.6% by the control veins. The differences were significant between the vein bypass grafts and the control arteries (p less than 0.04 for acetylcholine; p less than 0.04 for A23187) and the control veins (p less than 0.03 for acetylcholine; p less than 0.02 for A23187). Perfusion of saphenous veins used as chronic arterial bypass grafts with either acetylcholine or A23187 produced detector vessel relaxation, consistent with endothelium-dependent relaxing factor production. The magnitude of the relaxation response did not approach that from perfusion of control arteries.     

Effect of target artery location and severity of stenosis on mid-term patency of aorta-anastomosed vs. internal thoracic artery-anastomosed radial artery grafts.

OBJECTIVE: To verify the effect of location and severity of stenosis of the target coronary artery (TCA) on mid-term patency of aorta-anastomosed vs. internal thoracic artery (ITA)-anastomosed radial artery (RA) graft. METHODS: During a 3-year period 228 consecutive patients received an RA graft at our institution. In 131 cases the RA was anastomosed to the aorta whereas in 97 the proximal anastomosis was performed on a mammary graft. The two groups were comparable in terms of preoperative variables and TCA characteristics. At a mean follow-up of 6.5 years 128 cases of the aorta-anastomosed and 95 of the mammary-anastomosed group were submitted to control angiography. RESULTS: Mid-term patency and perfect patency rates were 92.1 and 89.8% (118/128 and 115/128) for aorta-anastomosed RA vs. 86.3 and 84.2% for mammary-anastomosed grafts (82/95 and 80/95; P=0.81 and 0.82). The location of TCA did not influence graft patency in the two groups. The severity of the TCA stenosis strongly influenced graft patency in both groups but the threshold for failure was clearly higher in the mammary-anastomosed group. CONCLUSIONS: ITA-anastomosed RA grafts are more vulnerable to the detrimental effect of chronic native competitive flow and should be used only for target vessel with subocclusive stenosis. The location of the distal anastomosis does not influence long-term RA patency.     

Histology and morphology of 59 internal thoracic artery grafts and their distal anastomoses

BACKGROUND: The left internal thoracic artery (LITA) is accepted as a superior graft for the left coronary system because of its better long-term patency rate than saphenous grafts. The postsurgical histomorphometric changes at the distal anastomosis of LITA grafts are not well documented. METHODS: The cellular changes within the intima of 59 LITA grafts were analyzed by light microscopy. RESULTS: Grafts implanted 1 week or less (n = 34) showed no postsurgical tissue proliferation. Of the 7 grafts implanted 1 to 8 weeks, only the suture sites exhibited intimal thickening (6 of 7 grafts, 0.08 +/- 0.07 mm). The remaining grafts (n = 18), aged 2 months to 10 years, showed significant intimal thickening at the suture sites (0.39 +/- 0.17 mm) and on the hood (0.29 +/- 0.25 mm), with variable thickening on the floor (10 of 18 left anterior descending coronary arteries, 0.11 +/- 0.12 mm). The graft body showed insignificant intimal changes (10 of 18, 0.03 +/- 0.04 mm), with mild focal atherosclerotic lesions in 2 of 18 late LITA grafts. CONCLUSIONS: Left internal thoracic artery grafts develop fibromuscular intimal hyperplasia primarily around the anastomosis. The response on the hood appears to be a hemodynamic response, secondary to that of the suture sites.     

Left internal thoracic artery-radial artery composite grafts as the technique of choice for myocardial revascularization in elderly patients: a prospective randomized evaluation

OBJECTIVES: The technique of choice for myocardial revascularization in elderly patients remains a debated issue. We evaluated the potential advantages of the use of left internal thoracic artery-radial artery composite grafts compared with conventional coronary artery bypass grafts in elderly patients. METHODS: We prospectively enrolled 160 patients aged more than 70 years scheduled to undergo isolated myocardial revascularization. Patients were assigned at random to group 1, 80 patients undergoing total arterial revascularization (left internal thoracic artery on left anterior descending coronary artery plus radial artery), or group 2, 80 patients undergoing standard coronary artery bypass graft surgery (left internal thoracic artery on left anterior descending coronary artery plus saphenous veins). The radial artery was used in all cases as a composite Y-graft. RESULTS: Preoperative characteristics and risk factors (EuroSCORE: group 1 = 7.9 vs group 2 = 8.1), number of grafted coronary vessels (group 1 = 2.4 vs group 2 = 2.5), aortic crossclamping time (group 1 = 37 +/- 7 minutes vs group 2 = 38 +/- 7 minutes), ventilation time (group 1 = 22 +/- 12 hours vs group 2 = 23 +/- 11 hours), intensive care unit stay (group 1 = 39 +/- 10 hours vs group 2 = 40 +/- 9 hours), and hospital mortality (group 1 = 3.8% vs group 2 = 5%) were comparable between the groups. Comparison between the 2 groups in terms of early postoperative complications showed a higher incidence of cerebrovascular accidents in group 2 (group 1 = 0 patients vs group 2 = 4 patients, 5%). At a mean follow-up of 16 +/- 3 months, patients in group 1 showed superior clinical results with a lower incidence of graft occlusion (group 1 = 2 vs group 2 = 11; P =.06) and angina recurrence (group 1 = 2 patients vs group 2 = 12 patients; P =.03). Multivariate analysis identified saphenous vein grafts as independent predictors for graft occlusion and angina recurrence. CONCLUSIONS: Left internal thoracic artery-radial artery composite grafts proved to be a safe procedure in elderly patients. It improved the clinical outcome, providing a significantly higher graft patency rate and a lower incidence of late cardiac events.     

Effect of flow competition on internal thoracic artery graft: postoperative velocimetric and angiographic study

OBJECTIVES: To assess the effects of competitive blood flow on internal thoracic artery grafts, we investigated postoperative flow velocity characteristics and angiographic findings of the grafts with various grades of native coronary artery stenosis. METHODS: Fifty patients who had an internal thoracic artery graft to the left anterior descending artery underwent intravascular Doppler graft velocimetry during postoperative angiography. Patients were divided into 3 groups according to the grade of native coronary stenosis: group H (28 patients), 80% stenosis or greater; group M (16 patients), 60% to 79% stenosis; and group L (6 patients), 40% to 59% stenosis. Phasic flow velocity of the grafts was measured with an intravascular Doppler ultrasound-tipped guide wire during angiography. Graft flow volume was calculated from the diameter and the average peak velocity. RESULTS: Average peak velocity (group H, 27.1 +/- 8.6 cm/s; group M, 16.9 +/- 3.9 cm/s; group L, 7.2 +/- 3.7 cm/s), distal graft diameter (group H, 2.27 +/- 0.23 mm; group M, 2. 00 +/- 0.28 mm; group L, 1.07 +/- 0.27 mm), and calculated graft flow volume (group H, 33.1 +/- 12.0 mL/min; group M, 16.2 +/- 5.8 mL/min; group L, 2.3 +/- 2.0 mL/min) significantly differed among the 3 groups. Graft flow in diastole and systole also differed among the 3 groups. CONCLUSIONS: Competitive blood flow reduces internal thoracic artery graft flow and diameter according to the grade of the native coronary artery stenosis. These data suggest that grafting the internal thoracic artery to the coronary artery with stenosis of a low grade can cause graft atrophy and failure.     

Myocardial revascularization with radial and mammary arteries: initial and mid-term results

BACKGROUND: The radial artery is being used with increasing frequency instead of the saphenous vein in coronary artery bypass grafts. We analyzed the in-hospital and midterm results in patients undergoing coronary artery bypass surgery in whom a combination of arterial grafts was used, including radial artery and one or both internal mammary arteries. METHODS: Between 1995 and 1998, 1,023 patients underwent coronary artery bypass surgery using arterial conduits. The left internal mammary artery and the right internal mammary artery were employed in combination with the radial artery. RESULTS: An average of 3.2 grafts per patient were done. The left internal mammary artery and radial artery were used in 100% of patients, the right internal mammary artery in 21.7%, and a venous graft in 31%. The operative mortality rate was 2.5%. On repeat angiography performed in 62 patients before their discharge, the arterial conduits were patent in 98.4%. Mean follow-up was 25.0 +/- 9.6 months (1 to 48 months). The probability of survival was 92.8%. CONCLUSIONS: Revascularization using mammary and radial artery grafts is safe. Complications are not higher than those observed with saphenous vein grafting. It was possible to use arterial conduits in all the patients, even in those with impaired left ventricular function.     

Benefits accruing to grafting of the right internal thoracic artery to the left anterior descending artery in coronary artery bypass grafting.

OBJECTIVES: We have investigated the effects and outcome from grafting the right internal thoracic artery to the left anterior descending artery in coronary artery bypass grafting. METHODS: We analyzed the findings in 185 patients who underwent coronary artery bypass grafting involving right internal thoracic artery-left anterior descending artery bypass. The survival rate, cardiac events related to the right internal thoracic artery-left anterior descending artery graft, and graft patency were investigated. In cardiac catheterization, the production of nitric oxide from the endothelium of the internal thoracic artery was measured as the plasma nitrite and nitrate levels by the Griess reaction. The reactions to acetylcholine infusion (5 micrograms) in the right internal thoracic artery (n = 4) were compared to those in the left internal thoracic artery (n = 9) grafts. RESULTS: The hospital mortality rate was 0.5%. The actuarial survival rate at 11 years after operation was 98.81%. The rate of freedom from cardiac events at 11 years after operation was 92.08%. The rate of patency of the right internal thoracic artery-left anterior descending artery was 97.0% in 133 patients. Nitric oxide production was calculated as (total nitrite plus nitrate production in response to stimulation by acetylcholine-total nitrite plus nitrate level before acetylcholine load)/(total nitrite plus nitrate level before acetylcholine load). There was no significant difference in changes in plasma concentration in response to acetylcholine stimulation between the right internal thoracic artery-left anterior descending artery and left internal thoracic artery-left anterior descending artery groups (20 +/- 29% versus 5 +/- 10%). CONCLUSIONS: The right internal thoracic artery-left anterior descending artery grafts exhibited good patency and release of nitric oxide in response to acetylcholine loading, similar to left internal thoracic artery-left anterior descending artery grafts.     

Radial artery patency and clinical outcomes: five-year interim results of a randomized trial

OBJECTIVE: This study was undertaken to compare elective angiographic patency and cardiac event-free survival of the radial artery graft with that of the free right internal thoracic artery or saphenous vein during a 10-year period after primary coronary artery bypass surgery. METHODS: This prospective, randomized, single-center trial was conducted on two groups of patients undergoing primary coronary artery bypass surgery. In a younger group (group 1, n = 285, <70 years), the radial artery was compared with the free right internal thoracic artery. In an older group (group 2, n = 153, >/=70 years), the radial artery was compared with the saphenous vein. The trial conduit was grafted to the largest available coronary artery other than the left anterior descending coronary artery. Angiography was scheduled at intervals between 0 and 10 years according to a second random assignment. Patients were followed up at yearly intervals to assess clinical outcomes. Clinical outcomes were analyzed on an intent-to-treat basis during the 10-year follow-up with time-related analyses. This interim study reports angiographic and clinical outcome results during the first 5 years. RESULTS: Graft patency estimates were as follows: 0.95 (95% confidence interval 0.85-0.99) in 39 radial arteries versus 1.0 in 29 right internal thoracic arteries (P =.4) in group 1, and 0.86 (95% confidence interval 0.67-0.99) in 24 radial arteries versus 0.95 (95% confidence interval 0.83-0.99) in 22 saphenous veins (P =.5) in group 2. Cardiac event-free survival estimates were as follows: 0.91 (95% confidence interval 0.76-0.99) for the radial artery versus 0.82 (95% confidence interval 0.63-0.99) for the right internal thoracic artery (P =.7) in group 1, and 0.84 (95% confidence interval 0.64-0.99) for the radial artery versus 0.89 (95% confidence interval 0.72-0.99) for the saphenous vein (P =.9) in group 2. CONCLUSION: The 5-year interim results do not support the hypothesis that the radial artery has superior patency to or is associated with fewer clinical events than free right internal thoracic artery or saphenous vein grafts.     

Severity of coronary artery stenosis at preoperative angiography and midterm mammary graft status

BACKGROUND: The purpose of this study was to evaluate the correlation between the midterm angiographic results of mammary artery grafts and the preoperative stenosis of the target vessel. METHODS: We analyzed preoperative and postoperative angiograms of 93 patients who underwent postoperative midterm (> or = 3 years) angiograms of an internal mammary artery (IMA) to left anterior descending artery graft for clinical or study purposes. Patients were divided into three groups on the basis of the percentage of the coronary artery stenosis at preoperative angiography: < 70%, 70% to 90%, and > 90% stenosis. RESULTS: Preoperative characteristics were similar in the three groups. The overall incidence of IMA occlusion was 19% in the entire population, without significant differences between groups (19% versus 29% versus 14%). The mean mammary artery diameter significantly increased in direct proportion to the severity of the coronary stenosis (2.0 +/- 0.2 mm in the < 70% versus 2.5 +/- 0.3 mm in the 70% to 90% and 2.7 +/- 0.4 mm in the > 90% series; p < 0.05). CONCLUSIONS: Chronic native competitive flow does not significantly affect midterm graft status but does influence mammary graft diameter.     

Functional integrity and aging of the left internal thoracic artery after coronary artery bypass surgery

OBJECTIVE: To study the endothelial function in the left internal thoracic artery after coronary artery bypass surgery and to identify predictors of early dysfunction, we performed a provocative test with acetylcholine in 23 male patients who underwent routine postoperative coronary angiography. METHODS: The change in mean diameter of the proximal thoracic artery was assessed by quantitative angiography after selective injections of acetylcholine and nitroglycerin. RESULTS: The thoracic artery showed a 6.8% (P <. 001) and 9.0% (P <.001) increase in mean diameter after acetylcholine and nitroglycerin administration, respectively. Vasodilative responses to acetylcholine and nitroglycerin administration were strongly correlated (R: 0.88; P <.001). Among the common risk factors, only age was associated with an impairment in the vasodilative response of the arterial graft (P =.001), and acetylcholine-induced vasodilation was inversely correlated to the age of the patient (R: 0.69; P <.001). CONCLUSIONS: Endothelium-dependent vasodilative response to acetylcholine administration seems well preserved in the left internal thoracic artery after surgery. Common risk factors, except for age, do not affect the functional integrity of the arterial graft. The vasodilative properties of the graft depend on the age of the patient and do not deteriorate over time after operation.     

Angiographic results of the radial artery graft patency according to the degree of native coronary stenosis.

OBJECTIVE: Radial arteries are gaining widespread acceptance as complementary arterial conduits for surgical myocardial revascularization, but there are limited reports about its angiographic patency compared with that of the internal thoracic artery or saphenous vein according to the degree of native coronary stenosis. Therefore, we tried to evaluate the mid-term angiographic results of the radial artery graft patency focusing on the native coronary stenotic status in a prospective manner. METHODS: From March 2000 to September 2006, a total of 488 patients underwent coronary artery bypass grafting using radial artery graft at our institution. From this group, 123 patients (mean age of 59.02+/-8.9 years (range 34-73 years)) were enrolled in the present study, and underwent a postoperative angiography after surgery (mean 32 months). The angiograms were assessed visually and quantitatively. RESULTS: A total of 382 distal anastomoses were performed and 352 anastomosis remained patent (92.1%). Left internal thoracic artery showed the most excellent patency in all of the conduits (128/129, 99.2%). Overall the radial artery graft patency was 92% (160/174). In the univariate analysis, patency was significantly worse for targets of the right coronary system (left coronary system 129/135, 94.4% vs right coronary system 31/39, 79.4%. p<0.05) and the radial artery graft showed a higher patency rate in the case of a severe stenotic lesion that preoperatively revealed more than 90% stenosis (defined as critical stenotic lesion) than in the case of a less severe lesion (50%相似文献   

Blood flow in composite arterial grafts and effect of native coronary flow

BACKGROUND: Total arterial coronary revascularization can be achieved by joining arteries together as a composite graft with the proximal left internal mammary artery as the only source of blood inflow. Proof of the capacity of this composite conduit to provide adequate blood flow to the coronary circulation is required. METHODS: The radial artery was anastomosed to the left internal mammary artery as a Y graft in 17 patients and all coronary arteries grafted. Intraoperative blood flow through the composite grafts was evaluated by the transit-time Doppler technique. RESULTS: Against no resistance, blood flow in the left internal mammary artery alone was 99 +/- 9 mL/min and rose to 173 +/- 16 mL/min when the radial artery was anastomosed as a Y graft. Composite-graft flow following grafting was 88 +/- 9 mL/min, 49 +/- 6 mL/min when the aortic clamp was removed and native coronary flow restored and 82 +/- 13 mL/min following weaning from cardiopulmonary bypass. The maximal potential flow through the composite graft was 2.3-fold (95% CI 1.6 to 3.2) greater than that after cardiopulmonary bypass. CONCLUSIONS: Total arterial revascularization, using a composite graft, provided a 2.3-fold reserve of blood flow to the coronary vascular bed through the grafts.     

Normal endothelial function and decreased vasoreactivity of experimental arterial grafts

During autogenous vascular grafting endothelial cell damage inevitably occurs. In this study we examined the functional and morphologic integrity of experimental arterial grafts. The right external iliac artery was grafted into the right carotid artery of 12 male New Zealand white rabbits. The left external iliac artery was used as the control artery. Four weeks after surgery, isometric tension studies were performed on rings of control artery and arterial graft. Control arteries and arterial grafts precontracted with norepinephrine demonstrated endothelium-dependent relaxation of 28.3% +/- 5.6% and 16.1% +/- 1.7%, respectively, in response to acetylcholine (5 x 10(-6) mol/L). Both control arteries and arterial grafts contracted in response to norepinephrine, histamine, and serotonin. The median effective dose (ED50) of norepinephrine was 4.1 +/- 1.3 x 10(-7) mol/L for control arteries and 62.1 +/- 17.9 x 10(-7) mol/L for arterial grafts (p less than 0.005). Similarly, arterial grafts were less sensitive to histamine; the ED50 of histamine for control arteries was 4.6 +/- 1.3 x 10(-7) mol/L and 51.4 +/- 13.0 x -7 mol/L for arterial grafts (p less than 0.005). In contrast, reactivity to serotonin was unaltered. The ED50 was 4.1 +/- 1.3 x 10(-7) mol/L for control arteries and 4.5 +/- 1.3 x 10(-7) mol/L for arterial grafts. Scanning and transmission electron microscopy revealed a largely intact endothelial surface. These data are markedly different from our previous findings with vein grafts in which serotonin supersensitivity was associated with an absence of endothelium-mediated relaxation to acetylcholine.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

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.     

Has the in situ right internal thoracic artery been overlooked? An angiographic study of the radial artery, internal thoracic arteries and saphenous vein graft patencies in symptomatic patients.

OBJECTIVE: The right internal thoracic artery is being used infrequently despite favorable observational angiographic data. Conversely, the radial artery utilization has increased with only limited data available. The purpose of this paper is to re-evaluate the roles of the right internal thoracic artery and the radial artery grafts. METHODS: We reviewed all ischemia-directed coronary angiographic procedures from January 1996 to December 2003. A total of 219 patients had primary coronary artery bypass grafting with an internal thoracic artery and a radial artery as two of the bypass grafts. Six hundred and seventy-nine (679) graft angiograms (45 saphenous vein, 363 radial artery, 54 right internal thoracic artery and 217 left internal thoracic artery) were studied. The mean period from operation to re-angiogram was 1104+/-761 days. Angiographic outcomes were divided into groups as: (1) patent (<50% stenosis) or (2) failed (>or=50% stenosis, string sign or occluded). A generalized linear mixed model was used to analyze predictors of graft patency. Turnbull's estimates of cumulative patency were used to compare graft failure rates over time. RESULTS: A total of 632/679 (93%) grafts were patent and 47/679 (7%) grafts had failed. Empirical saphenous vein graft patency was 40/45 (89%), radial artery patency 329/363 (91%), right internal thoracic artery patency 51/54 (94%) and left internal thoracic artery patency 212/217 (98%). Pairwise comparisons of patency from the generalized linear mixed model were: LITA>RITA, OR=1.5 (P=0.5); LITA>RA, OR=5.7 (P<0.001); LITA>SV, OR=6.5 (P<0.001); RITA>RA, OR=3.9 (P=0.01); RITA>SV, OR=4.4 (P=0.01); RA>SV, OR=1.1 (P=0.7). Five-year patency estimates from the Turnbull's model were the left internal thoracic artery (95.9%), right internal thoracic artery (91.2%), the radial artery (90.6%) and the saphenous vein (81.8%). CONCLUSIONS: Consideration should be given to the routine use of both internal thoracic arteries for coronary artery bypass grafting. When additional grafts are required, there is no evidence to suggest that either the radial artery or saphenous vein is superior.     

Complete arterial coronary revascularisation using radial artery conduit for double thoracic artery inlet flow: arterial sling operation.

BACKGROUND: Coronary artery bypass graft surgery with arterial revascularisation of all diseased coronary vessels is considered highly efficient because arterial grafts have an excellent long-term patency compared with venous grafts. However, problems to reach the infero-lateral wall with the in situ internal thoracic arteries usually require alternative techniques. We present the first results of a new surgical principle using a free radial artery segment to complete the arterial coronary revascularisation and concomitantly connect the internal thoracic arteries. METHODS: In patients referred for coronary bypass surgery and three-vessel disease an end-to-end anastomosis of the right internal thoracic artery and the radial artery segment preceded cardiopulmonary bypass, during which side-to-side anastomoses of the radial artery segment were used to revascularise stenotic branches of the right coronary and circumflex arteries. The left internal thoracic artery was used for revascularisation of stenotic branches of the left anterior descending artery, and finally an end-to-side anastomosis of the radial artery segment to the left internal thoracic artery was performed. Coronary artery blood flow was measured in 41 patients with Doppler flow probe. RESULTS: One hundred and ninety-two coronary anastomoses (an average of 4.2 per patient) were performed in 46 patients. We measured a mean total blood flow in the arterial sling graft of 104ml/min (range 35-221ml/min), compared with 69 and 68ml/min of the single inlet right and left internal thoracic arteries, respectively (P<0.01). Flow capacities of 104 and 120ml/min of the right and left internal thoracic arteries were measured during clamp of both the aorta and the contralateral internal thoracic artery. The mean crossclamp duration was 77min (range 51-113min). Postoperative angiography demonstrated patent graft anastomoses to all coronary arteries. There were no perioperative deaths or myocardial infarctions. One patient had a minor postoperative stroke. DISCUSSION: Complete arterial revascularisation can be achieved by the arterial sling operation with an acceptable crossclamp time and a high early rate of graft patency. The double arterial inlet provides a 50% higher blood flow to the beating heart and two-fold increase in the flow reserve compared with a single inlet. Although further research including long-term follow-up of this new principle is required, the present findings seem promising and suggest that the arterial sling operation has a potential role for complete arterial coronary revascularisation.