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An asymptomatic young woman was found to have a continuous machinery murmur over the second right interspace near the sternum. Investigations showed an arteriovenous fistula involving the right internal thoracic artery and accompanying vein. Selective transcatheter embolization was successfully performed.
A new method to skeletonize and harvest the internal thoracic artery using an ultrasonic scalpel is presented. The technique is simple, safe, and minimally invasive. It is possible to obtain sufficient vessel length for anastomosis to most coronary arteries for bypass grafting.
BACKGROUND: We examined the hypothesis that complete skeletonization of an internal thoracic artery (ITA) results in increased diameter of the graft for anastomosis and therefore improves graft flow in coronary artery bypass grafting. METHODS: We studied 65 consecutive patients who underwent coronary artery bypass grafting, in which the left ITA was anastomosed to the left anterior descending artery. The first 20 consecutive ITA were harvested as a pedicle (group P) and later 45 consecutive ITAs were harvested as an ultrasonically skeletonized graft (group S). Intraoperative ITA graft mean flows were obtained with a transit-time flowmeter. Three diameters of the ITA graft were measured quantitatively in postoperative angiograms performed 14 +/- 5 days after the coronary artery bypass grafting; D1, at the origin from the subclavian artery; D2, at the level of the second intercostal space; and D3, just proximal to the anastomosis. RESULTS: Intraoperative mean flow was significantly greater in group S than in group P (S: 42.6 +/- 29.1 mL/min versus P: 26.4 +/- 16.1 mL/min, p = 0.03). Although the diameters D1 and D2 were not significantly different between groups, D3 was significantly larger in group S than in group p (S: 1.77 +/- 0.28 mm versus P: 1.57 +/- 0.17 mm, p = 0.02). CONCLUSIONS: Compared with pedicle harvesting, complete skeletonization of ITA may make it possible to anastomose an ITA with a larger diameter in coronary artery bypass grafting, which leads to increased graft flow by decreasing vascular resistance.
OBJECTIVE: The internal thoracic artery (ITA) is the most important graft in coronary artery bypass grafting. Its distal region is, however, prone to vasospasm. We studied the effects of nitroglycerin (NTG) and isosorbide-dinitrate (DSDN) on distal segments of left versus right ITA. METHODS: Rings of distal segments (6 to 9 mm proximal to bifurcation) of the human left and right ITA were studied. After baseline contraction of the rings, achieved using 60 mmol/L of KCl, they were exposed to increasing doses of ISDN and NTG (10 to 100 microg/ml), and dose-response curves were recorded. RESULTS: The contractile response of left ITA rings to KCl were significantly lower than those of right ITA rings (1.87 +/- 0.25 g versus 3.5 +/- 0.61 g, p < 0.005). Both nitrates inhibited the contractile response in a concentration-dependent manner, with relaxing effects of ISDN higher than those of NTG (p < 0.01) in both left and right ITA rings. CONCLUSIONS: The distal segment of the left ITA is less prone to vasospasm than that of the right. ISDN has a considerably higher relaxant effect on this segment than NTG. We therefore recommend favoring high doses of ISDN over NTG as an antispastic measure.
Immediately after undergoing coronary bypass grafting using the left internal thoracic artery, a 59-year-old man developed left leg ischemia. Right-to-left femoral artery crossover bypass was performed and the ischemia resolved. A 72-year-old man developed left calf pain 12 days after a similar procedure; peripheral angiography revealed stenosis of the abdominal aorta and distal peripheral arteries, which did not require intervention.
BACKGROUND: Concerns have been raised regarding the accuracy of the left internal thoracic artery (LITA) anastomosis performed during minimally invasive direct coronary artery bypass (MIDCAB). In a prospective study, we tested the hypothesis that transthoracic Doppler echocardiography is an adequate technique to determine LITA patency when compared to "gold standard" postoperative angiography. METHODS: Seventy-two consecutive patients with single left anterior descending (LAD) coronary artery stenosis were submitted to MIDCAB performed on a beating heart using the LITA. All patients underwent transthoracic Doppler Echocardiography and angiography before discharge. LITA was considered patent when diastolic fraction (DF) of time-velocity integral was equal or greater than 0.5. FitzGibbon grading system was used to evaluate LITA patency by angiography (A=excellent; B=stenosis reducing caliber of anastomosis or trunk to < 50% of grafted coronary artery; O=occlusion). RESULTS: Angiography showed that LITA was patent in 70 (97.2%) patients, 69 of them been graded A. Adequate image and flow signal of the LITA was achieved in 65 (90.3%) patients, been considered patent in 61 (93.8%) of them. Comparison between echocardiography and angiography in these 65 patients showed a specificity of 96.8% and a sensitivity of 50%. In 7 (9.7%) patients in whom no adequate echocardiography signal was obtained, the LITA graft was normal in six and occluded in one. CONCLUSIONS: For patients whose LITA graft can be imaged, transthoracic Doppler echocardiography is highly specific and is a valuable method for noninvasive evaluation of LITA graft patency after MIDCAB.
The aim of this study was to examine the internal thoracic artery (ITA) in human foetuses. The research material consisted of 32 human foetuses (18 female, 14 male) from the 21(st) to 24(th) week of intrauterine life. After intravascular injection with white latex LBS 3060, the foetuses were fixed in 10% neutral formalin solution. The whole course of the ITA was prepared. Photographic documentation was performed with a Nikon Coolpix 4500 digital camera, and source pictures of arteries were rendered in a Digital Computer System Analysis. The ITA was evaluated with regard to its origin, length, distance from the edge of the sternum to two intercostal spaces (2(nd), 5(th)) and division into terminal branches. The right ITA (RITA) arose from the ascending (68.7%), arcuate (21.9%) and descending (3.2%) parts of the subclavian artery. In other cases (6.2%) it was a branch of the thyrocervical trunk. The left ITA (LITA) was a branch of the ascending (78.1%) and arcuate (21.9%) parts of the subclavian artery. The ITA was longer in male foetuses. Regardless of sex, the LITA was longer than the RITA. Coefficient correlation between the RITA and LITA was 0.92 (p < 0.001). The distance of the ITA from the edge of sternum in the 2(nd) and 5(th) intercostal spaces on both sides was greater in females. It appeared most frequently in the 6(th) space (43.7% right-sided and 56.3% left-sided). Typical bifurcation of the ITA into the superior epigastric artery and the musculophrenic artery was observed in 78.1% of cases on the right side and in 81.25% of cases on the left side.
The patency rate of radial artery (RA) conduits is considerably lower than that of internal thoracic artery (ITA) grafts and the evidence suggests that this is due to a clinically suspected higher incidence of vasospasm. The aim of this study was, therefore, to compare intraindividually the pharmacological reactivity of RA with that of ITA. Both RA and ITA were taken from the same patients and investigated in parallel. Changes in tone were monitored isometrically on ring preparations from both arteries in organ baths with modified Krebs-Henseleit solution containing 1.25 mm calcium chloride at 1 g passive preload. In intraindividual comparisons maximal receptor-mediated contractile responses to noradrenaline and endothelin-1 and endothelium-dependent acetylcholine-induced relaxant responses revealed no differences between both arteries. By contrast, depolarization-induced contractions to potassium chloride (KCl) appeared to be significantly higher in RA than in ITA. Further analysis, however, revealed that this difference was due to preoperative calcium entry blocker (Ca(2+)eB) therapy. Compared with control tissues, maximal responses to KCl were significantly attenuated in the ITA but unchanged in RA when arteries were obtained from patients with preoperative Ca(2+)eB therapy. The present results suggested that functional responses to pharmacological stimuli of both RA and ITA were quite similar. Preoperative Ca(2+)eB therapy, however, attenuated markedly responses to KCl of the ITA leaving those of RA unchanged. These results, demonstrating a lower sensitivity to Ca(2+)eB of RA, therefore suggested that in addition to Ca(2+)eB other classes of drug may be more effective at reducing the propensity of RA conduits to vasospasm.
BACKGROUND: Early postoperative coronary angiography was performed to establish the feasibility of treating patients with triple-vessel disease by performing completely arterial revascularization on the beating heart using only bilateral internal thoracic arteries (ITAs). METHODS: Between March 2001 and February 2003, 113 patients with triple-vessel disease (age, 62.0 +/- 8.6 years) underwent beating heart revascularization using only the bilateral ITAs. Left ventricular ejection fractions ranged from 23% to 78% (mean, 51.3% +/- 15.1%). The incidence of diabetes mellitus was 46%. Early postoperative coronary artery angiographic follow-up was performed since May 2002 in the last 59 sequential patients. RESULTS: There were no operative deaths. Perioperative myocardial infarction and postoperative low cardiac output occurred in only 1 patient each. The mean number of distal anastomoses was 3.9 +/- 0.7 per patient. The patency rates were 100% for the left ITA and 98.1% for the right. Competitive flow patterns were present in 25 distal anastomosis sites (10.5%). A multivariate analysis showed that the degree of stenosis (<75%), the extent of focal stenosis of the native coronary artery, and the intraoperative transit-time flow rate (<10 mL/min) were the statistically significant risk factors for competitive flow. CONCLUSION: This surgical strategy is feasible, is safe, and yields good early angiographic outcomes, even following beating heart revascularization. However, in less significant lesions competitive flow patterns were relatively prevalent, so this technique might be reserved until it is proven to provide good long-term patency and function.
A 38-year-old male underwent coronary artery bypass grafting (CABG). A saphenous vein graft was attached to the left marginal branch. The left internal thoracic artery was anastomosed to the left anterior descending artery (LAD). The early recovery was uneventful and the patient was discharged on the 5th postoperative day. After three months, he came back to the hospital complaining of weight loss, weakness, and dyspnea on mild exertion. Chest X-rays showed left pleural effusion. On physical examination, a decreased vesicular murmur was detected. After six days, the diagnosis of chylothorax was made after a milky fluid was detected in the plural cavity and total pulmonary expansion did not occur. On the next day, both anterior and posterior pleural drainage were performed by videothoracoscopy, and prolonged parenteral nutrition (PPN) was instituted for ten days. After seven days the patient was put on a low-fat diet for 8 days. The fluid accumulation ceased, the drains were removed and the patient was discharged with normal pulmonary expansion.
OBJECTIVE: We investigated the mechanism of the protamine action and the effects of free hemoglobin on protamine-induced responses in endothelium-denuded and-intact human internal thoracic artery (ITA) rings precontracted with phenylephrine (PE) or high KCl. METHODS: Samples of redundant ITA obtained from patients undergoing a coronary artery bypass graft surgery were cut into 3 mm wide rings and suspended in 20 ml organ baths. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. RESULTS: Acetylcholine (Ach, 10(-8)-10(-5) M) caused a concentration-dependent relaxation of PE-precontracted ITA rings. Free hemoglobin (0.1 and 0.5 microM) produced a concentration-dependent and significant decrease in sensitivity (pD(2)) and maximal contractility (E(max)) in response to Ach in PE-precontracted ITA rings (P<0.0001). Protamine (50-800 microg/ml), free hemoglobin (0.1 and 0.5 microM), nitric oxide (NO) blocker N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM) or soluble guanylate cyclase inhibitor methylene blue (10 microM) administration did not cause a significant alteration on basal tonus of endothelium-intact or -denuded ITA rings. Protamine (50-800 microg/ml) induced concentration-dependent relaxation responses in ITA rings precontracted by either PE or high KCl. There was no difference in sensitivity or maximal response to protamine between the endothelium-intact and -denuded rings. Incubation of endothelium-intact or -denuded ITA rings with L-NAME or free hemoglobin or methylene blue did not cause a significant inhibition on relaxation responses to protamine. ITA ring contractions induced by stepwise addition of calcium to high KCl solution with no calcium were almost completely inhibited by protamine (P<0.0001). CONCLUSIONS: It was suggested that protamine induced relaxation responses in human ITA rings is not NO- or endothelium-dependent but seems to depend on the interactions of protamine with calcium influxes and/or calcium release from intracellular stores in this tissue.
BACKGROUND: There is a tendency to avoid the bilateral internal thoracic artery (ITA) grafting in diabetics. However, we no longer consider diabetes a reason for excluding the bilateral use of ITAs. We compare the early and long-term results in diabetic cases treated by coronary artery bypass grafting (CABG) using unilateral and bilateral ITA grafts. METHODS: A total of 303 consecutive diabetic cases of CABG using ITA grafts between April 1991 and January 2003 were reviewed. Of these, 149 (49%) were being treated with insulin. The cases were divided into two groups: 179 cases in which bilateral ITA grafts had been used and 124 in which a unilateral ITA graft had been used. RESULTS: The mortality for the bilateral ITA group and unilateral ITA group were 1.7% and 1.6%, respectively. The fact that patients were receiving insulin had no effect on the mortality of CABG. A review of morbidity revealed that no differences were found between the two groups. The survival curves, cardiac-death-free curves, and cardiac-event-free curves showed that there was no difference between the use of one or two ITA grafts in diabetics, while bilateral use of ITA grafts was significantly better than unilateral use in a comparable group of nondiabetics operated during the same time period. CONCLUSIONS: There was no significant difference in operative mortality related to single or double ITA grafting in diabetics. There was also no difference between the use of one or two ITA grafts in diabetics in regard to long-term follow-up.
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.
Intraoperative perfusion contrast echocardiography (PCE) is a new method to evaluate regional myocardial perfusion using Albunx (air encapsulated albumin microspheres-Molecular Biosystems, Inc.) and has been employed by direct individual injection into human saphenous vein coronary bypass grafts. Because this is not an appropriate technique for assessing left internal thoracic artery (LITA) graft, we tested the hypothesis that PCE can be performed with a single aortic root injection and, thereby, provide regional perfusion data for LITA and native coronary flow. CABG (LITA to the left anterior descending artery (LAD) was performed in adult swine. PCE was performed in each of the following conditions: 1) LITA occluded, LAD 100% flow; 2) LITA 100% flow, LAD occluded; 3) LITA 50% flow, LAD occluded; and 4) LITA and LAD occluded. Time-intensity curves were constructed to assess the time to initial appearance of myocardial enhancement (TIA), peak contrast intensity (PI), and area under the enhancement curve (AUC). In 12/14 cases, (85.7%), adequate enhancement was achieved. LITA perfusion, when compared to perfusion through the native LAD, showed delayed appearance (TIA 0.4 +/- 0.1 vs 1.9 +/- 0.2 secs), reduced PI (43 +/- 3 vs 28 +/- 3 AU) and reduced AUC (247 +/- 115 +/- 19 AU) (p < 0.01) when LITA flow was reduced 50%, TIA was prolonged (1.7 +/- 0.2 vs 2.4 +/- 0.2 secs) and AUC was reduced (152 +/- 18 vs 88 +/- 20 AU) (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
OBJECTIVE: One of the most important factors in bypass surgery is the preservation of endothelial function in the arterial graft. It was of interest, therefore, whether a slightly modified preparation procedure during surgery could contribute to improved endothelial function of the graft. We compared the functional activity of internal thoracic arteries (ITA) prepared according to the traditional harvesting method with occlusion by a clip, dissection at the distal end and storage of the artery in papaverine until its implantation (CA) with the functional activity of arteries which were also prepared and wrapped in papaverine, but were left perfused and dissected immediately before their anastomoses (PA). METHODS: Samples of ITA were obtained from a total number of 28 patients, undergoing bypass surgery, and randomly distributed into two groups. The arteries were cut into rings and suspended in organ baths, containing Krebs-Henseleit solution, for isometric tension recording. Cumulative concentration response curves were determined for the contractile agents endothelin-1 (ET-1), 5-hydroxytryptamine (5-HT), noradrenaline (NA) and potassium chloride (KCl) and the relaxant compounds acetylcholine (ACH) and sodium nitroprusside (SNP) during active tone induced by 30 mM KCl. RESULTS: ET-1 and 5-HT stimulated rings from both groups within the same concentration ranges but elicited significantly (P<0.05) higher contractile responses in CA compared to PA. By contrast, concentration response curves for KCl and NA where nearly superimposable. On the other hand, maximal endothelium-dependent relaxant responses to ACH proved to be significantly stronger in PA (0.84+/-0.20 g) as compared to CA (0.31+/-0.05 g, P<0.05) while endothelium independent relaxant responses to SNP where similar in both groups. CONCLUSION: These data suggest that leaving the ITA perfused during harvesting might improve considerably the endothelial function of the graft.
Dyspnea with a slightly enlarged heart was noticed in a five year old girl at a checkup. The cardiological investigation revealed an enlarged left ventricle with slight mitral regurgitation. The right coronary artery was enlarged and filled the entire left arterial system via collaterals. The left main coronary artery could not be detected. In addition, outflow of contrast medium into the large vessels was absent. With the diagnosis of left main coronary atresia, the left internal thoracic artery was implanted on to the proximal left anterior descendent in October 1985. In the control angiogram, the anastomosis conditions were normal, the left ventricle had decreased in size and contracted almost normally. The collaterals from the right could no longer be demonstrated. The child (now six years old) has full exercise tolerance today. In the ultrasonogram, the ventricle shows normal contraction behavior. Up to know, four cases with congenital main coronary atresia have been reported in the literature.
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A case is reported of a 52-year-old man with bilateral internal thoracic artery (ITA) injury induced by blunt trauma. He was a laborer at a construction site who was hit on the anterior chest by a ceiling block. On arrival at the hospital at one hour after the accident, his general condition was good, and the chest computed tomography (CT) showed a slight hematoma at the mediastinum. However, at 4 hours after the trauma, the blood pressure fell, and the CT showed a large anterior mediastinal hematoma with bilateral hemothorax. A median sternotomy revealed bilateral ITA injury at the level of the 3rd intercostal space and incomplete fractures in the sternum and bilateral rib cartilages. Although hemostasis was achieved by ligation of the injured ITA, bleeding re-occurred from the ITA at the level of the 2nd intercostal space, and this was stopped by a second operation. The patient recovered without any further significant complication. The rarity of blunt trauma-induced ITA injury is discussed, including the mechanism, diagnosis, and treatment.