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PubMed1990

[Shortest route for in situ left thoracic artery to left anterior descending coronary artery].

For coronary artery bypass grafting, the internal thoracic artery (ITA) graft carries a greater long-term patency and a decreased need for reoperation when compared with the saphenous vein graft. However, the number and length of ITAs limit their use. In an effort to extend the use of the ITA and to improve patency, we evaluated the shorter course from the left ITA (LITA) origin to the left anterior descending coronary artery (LAD). We compared the distance using the conventional route over the lung (20 patients) with that using the newly-devised route medial to the lung and through the pericardial incision (20 patients). The distance using the route medial to the lung and through the pericardial incision was 12.6 +/- 1.4 cm (mean +/- SD), which was shorter compared with 15.1 +/- 1.1 cm of the route over the lung (p less than 0.01). And also the route medial to the lung and through the pericardial incision could avoid the danger of strectching or kinking by the inflated left lung. From these results, we concluded that the use of the route medial to the lung and through the pericardial incision was better method of extending the use of the in situ LITA to LAD.

Coronary Artery Bypass↗
PubMed1996

Early postoperative flow rates after internal thoracic artery grafting for the left coronary artery system.

OBJECTIVE: The low perioperative flow rates of internal thoracic artery (ITA) conduits have been regarded as a limitation of their use in critical coronary situations with a high myocardial blood demand. To clarify whether these restrictions are justified, early postoperative flow rates were determined. METHODS: Following bilateral ITA grafting, 48 of 106 patients (April 1993-September 1994) underwent recatheterization. Subsequent to control angiography between days 8 and 12, 20 of these patients were studied by intravascular Doppler techniques applied for ITA grafts supplying the left anterior descending artery (LAD) and branches of the circumflex system (CX) (n = 20). Doppler spectral analysis allowed for determination of the average peak velocity and diastolic-systolic velocity ratio. Vascular diameters were assessed by simultaneously performed quantitative angiography and mean flow rates were calculated. All parameters were recorded at rest and following selective stimulation with nitroglycerin (0.2 mg) and papaverine (12.5 mg) to evaluate the graft flow capacity. RESULTS: Baseline values of average peak velocity at rest were 24.6 +/- 11.5 cm/s for ITA-LAD conduits and 21.9 +/- 6.8 cm/s for ITA-CX pedicles. Following dilative stimulation with papaverine, a significant increase in average peak velocities were obtained for both locations (ITA-LAD: 47.3 +/- 17.1 cm/s, ITA-CX: 42.3 +/- 11.8 cm/s). The application of nitroglycerin had a similar effect (ITA-LAD: 42.6 +/- 15.3 cm/s, ITA-CX: 40.3 +/- 10.7 cm/s). The vascular diameters of ITA conduits remained unchanged on nitroglycerin stimulation, whereas papaverine effected significant dilatation in both locations. Flow rates at rest were not significantly different (ITA-LAD: 51.0 +/- 34.2 ml/min, ITA-CX: 44.7 +/- 16.4 ml/min) and maximal flow increase was observed following papaverine stimulation of the LAD conduits (116.1 +/- 90.6 ml/min). Dilative stimulation effected an increase in diastolic-systolic velocity ratios from average values at rest in a range between 34% and 41.7% for both groups and substances. CONCLUSIONS: The basic blood flow in functioning ITA grafts appears to be similar in conduits supplying the LAD and marginal branches. Flow rates between 50 and 60 ml/min at rest should meet myocardial demands, even in the LAD position. Increased flow rates were predominantly based on higher flow velocities with an increased diastolic flow proportion. Enlargement of the graft diameter may exert additional effects, at least following papaverine stimulation at a particular concentration.

Blood Flow Velocity↗
PubMed1995

Postoperative symptomatic internal thoracic artery stenosis and successful treatment with PTCA.

From 1988 to 1992, 4,182 coronary bypass grafting procedures were performed at the University of Ottawa Heart Institute. The left internal thoracic artery (ITA) was used in 2,913 patients, the right ITA in 79, and bilateral ITAs in 61 for a total of 3,053 patients with ITAs. This study assessed patients requiring angioplasty for symptomatic ITA stenosis after operation. A total of 29 patients (0.95%) with a mean age of 55.3 +/- 1.9 years underwent angioplasty for ITA stenosis from 4 days to 34 months after operation (mean, 6.5 +/- 1.6 months). Internal thoracic artery stenosis was identified in 18 patients (62.1%) within 3 months after operation. Angina was present in 26 patients (89.7%), a positive stress test in 8 (27.6%), and myocardial infarction in 1 (3.4%). At angiography, a total of 34 stenotic sites were identified in ITA grafts. Angioplasty was successful (< 50% residual stenosis) in 31 sites (91.2%). Follow-up was available for 28 of 29 patients (96.6%) at 24.6 +/- 2.3 months. Four patients (14.3%) returned with restenosis within 3 months, 2 of whom had successful repeat angioplasty, and 1 required reoperation. Canadian Cardiovascular Society anginal class after angioplasty was less than class II in 84.6% of patients. In conclusion, symptomatic postoperative ITA stenosis is uncommon, occurs most frequently at the site of distal anastomosis, and generally presents within 3 months of operation. It may be safely and effectively treated with angioplasty with a low recurrence rate.

Adult↗
PubMed1993

[Hemodynamic situation immediately after cardiopulmonary bypass in cases of coronary artery bypass grafting (CABG) using both bilateral internal thoracic arteries (ITAs) and right gastroepiploic artery (GEA)].

Hemodynamic situation immediately after cardiopulmonary bypass was studied in cases of CABG using bilateral ITAs and right GEA. Though cardiac output was kept greater than 4.0 l/min, the blood pressure soon after weaning from cardiopulmonary bypass was low in patients who necessitated further circulatory assist, intraaortic balloon pumping (IABP) and/or additional surgical bypass procedure. In cases of CABG using arterial grafts and no vein graft, the perfusion pressure is most important to stabilize the hemodynamic status because low pressure may provoke peripheral vasoconstriction resulting in spastic reaction of the ITA and GEA. These arterial grafts seemed to keep the characteristics as the peripheral artery. Some papers pointed out less flow capacity of arterial grafts compared with that of saphenous vein graft, but CABG with arterial grafts alone was safe clinically if care is taken for keeping the perfusion pressure as high as preoperatively.

Adult↗
PubMed1993

Exercise coronary flow reserve of bilateral internal thoracic artery bypass grafts.

We attempted to quantify the exercise coronary flow reserve in 20 patients with bilateral internal thoracic artery grafts to the left coronary arteries (group I) who had complete revascularization. The coronary sinus blood flow was measured by the continuous thermodilution method both at rest and during exercise (50 W for 8 to 9 minutes) approximately 1 month after the operation. These results were compared with 30 patients treated with an internal thoracic artery and saphenous vein grafts to the left coronary arteries (group II) and 9 patients with saphenous vein grafts alone to the left coronary arteries (group III). There were no differences among the three groups in age, sex, number of vessels involved, heart rate, double products, left ventricular (LV) end-diastolic pressure, LV ejection fraction, LV end-diastolic volume, or LV mass at the time of study. None of the 59 patients in the study had abnormally enlarged LV end-diastolic volume or increased LV mass. The postoperative coronary sinus blood flow per 100 grams of LV mass at rest was similar among the three groups (73.0 +/- 28.4 mL/min per 100 g LV mass in group I, 73.4 +/- 31.1 mL/min per 100 g LV mass in group II, and 75.9 +/- 28.5 mL/min per 100 g LV mass in group III [not significant]) and significantly (p < 0.01) increased by exercise, although the differences between groups during exercise were not significant (158.9 +/- 45.9, 153.5 +/- 72.1, and 148.3 +/- 60.0 mL/min per 100 g LV mass, respectively [not significant]).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1997

Improved survival with multiple left-sided bilateral internal thoracic artery grafts.

BACKGROUND: Although conceptually sound, the use of multiple internal thoracic artery (ITA) bypass grafts to improve long-term clinical results remains controversial. This operation typically involves grafting the left ITA to the anterior descending artery and the right ITA to the right coronary artery. Past clinical studies of bilateral ITA operations have not examined comparative results associated with which coronary arteries received the ITA bypass grafts. Because grafting a superior conduit to an artery of lesser physiologic importance might reduce the clinical benefits, we compared the outcomes of patients receiving different configurations of bilateral ITA operations. METHODS: The study group was 498 consecutive bilateral ITA operations, constituting the 10-year experience of a single surgeon. Follow-up averaged 7.1 years (mode 7.3 years), and was 94.2% complete. These patients were divided into two groups, 311 patients (group I) who underwent the traditional operation (left ITA to the left anterior descending artery, right ITA to the right coronary artery), and 187 patients (group II) who received revascularization of branches of the left coronary artery (left ITA to the circumflex system and right ITA to the left anterior descending artery). RESULTS: The study groups were similar in age, severity of disease, number of bypassed arteries, ejection fraction, diabetes, hypertension, and duration of operation. There were more male patients in group II (91.4% versus 82.3%). A multivariate analysis showed that the location of ITA bypass grafts influenced survival independent of gender (p = 0.0288). Operative morbidity and mortality were similar between groups. Ninety-three patients had repeat angiography with equivalent patency rates of the ITA conduits (91.7% versus 89.6%; p = 0.67). The Kaplan-Meier actuarial survival estimate demonstrated a significant improvement in survival of patients in group II who received both ITA bypass grafts to left-sided arteries (p = 0.021), with the survival curves diverging at 6 years. More patients in group II were in New York Heart Association class I or II, but the difference was not statistically significant (94.6% versus 91.6%). Only 2 patients required reoperation. CONCLUSIONS: It appears that maximum long-term benefit from bilateral ITA operations is achieved by grafting the ITA conduits to coronary arteries that supply more left ventricular muscle.

Coronary Angiography↗
PubMed1998

Angiographic follow-up of internal thoracic artery for free bypass grafting.

BACKGROUND: The use of free internal thoracic artery (ITA) grafts in patients with smaller body surface areas has been questioned because of technical difficulties and inadequate graft flow. METHODS: To evaluate postoperative changes in the diameter of free ITA grafts, we performed coronary angiography immediately after coronary artery bypass grafting and then again at a mean of 42 +/- 6 months later. In 20 consecutively treated patients, 21 free ITAs were used as bypass conduits. Two ITA grafts that were patent at the time of the first angiography had closed at the second angiography. Postoperative changes in ITA graft diameter were measured in the 19 patent ITA grafts. RESULTS: At the first angiography, the mean diameters of the proximal, middle, and distal ITA grafts were 2.28 +/- 0.45 mm, 2.34 +/- 0.39 mm, and 2.12 +/- 0.38 mm, respectively. At the second angiography, the mean diameters of the proximal, middle, and distal ITA grafts were 2.85 +/- 0.50 mm, 2.89 +/- 0.53 mm, and 2.72 +/- 0.53 mm, respectively. All segments of the ITA grafts had dilated significantly between the first and second angiographic evaluations (p < 0.01). The percentage change in graft diameter was greater when the initial ITA diameter was less than 2.3 mm (32.0% +/- 28.0%) than when it was 2.3 mm or more (18.8% +/- 11.3%) (p < 0.05). CONCLUSIONS: The postoperative increase in free ITA graft diameter depends on coronary blood flow requirements.

Adult↗
PubMed1991

[A case of bilateral internal thoracic artery bypass grafting in sudden death survivor with multivessel coronary spasms].

We report a 58-year-old male with a history of cardiac arrest due to coronary artery spasm, preoperative coronary arteriograms showed multivessel coronary spasm after the administration of ergonovine maleate associated with triple vessel fixed stenotic lesions. Under the use of cold diltiazem potassium-blood cardioplegic solution to prevent perioperative coronary spasm, coronary artery bypass grafting was performed. The right internal thoracic artery (ITA) was anastomosed to the left anterior descending artery and the left ITA to the circumflex artery. A saphenous vein graft was anastomosed to the right coronary artery. The postoperative course was uneventful. In postoperative coronary angiography with ergonovine stimulation, neither ITA grafts showed spastic changes, and the coronary artery distal to the anastomotic sites were well perfused through the ITA grafts. The patient has been free of angina without administration of calcium antagonist and been doing well for 2 years and 5 months since the operation.

Coronary Artery Bypass↗
PubMed2000

Internal thoracic artery as a collateral source to the ischemic lower extremity.

Based on the superior long-term results, internal thoracic artery is widely used for coronary artery bypass grafting. However, the vessel can play an important role as a collateral source to the chronically ischemic lower limbs. We reported two cases who underwent simultaneous revascularization to the myocardium and lower limbs because this particular condition was anticipated. Selective angiography of internal thoracic artery was useful to determine its role before harvesting in our cases. Careful preoperative examinations and choice of surgical approach are required for such patients to avoid serious vascular complications.

Angiography, Digital Subtraction↗
PubMed1994

Influence of endothelium and surgical preparation on responses of human saphenous vein and internal thoracic artery to angiotensin II.

1. The saphenous vein (SV) and internal thoracic artery (ITA) are the most commonly used conduits for coronary artery bypass surgery (CABS). The ITA shows better long term patency than the SV, at least in part due to their different responses to agonists, as well as physical differences between the ITA and SV at the time of grafting. 2. Angiotensin II (A II), a potent endogenous vasoconstrictor circulates at augmented levels during and after CABS, but little is known about the effects of A II on the SV and ITA. 3. We studied the contractile effects of A II on SV and ITA as intact rings from a heterogeneous group of patients undergoing CABS. Two groups of SV samples were studied; freshly excised SV (FSV) with no further manipulation and SV that had been surgically prepared for use as a bypass conduit (PSV). We also assessed the function of the endothelium in FSV, PSV and ITA, by measuring the relaxation of preconstricted rings to bradykinin. In some tissues endothelial presence was examined histologically. 4. Surgical preparation of SV affected the contractile ability of the smooth muscle, as PSV contracted less than FSV to potassium chloride (KCl, 90 mM) (P < 0.0001). Loss of endothelial function was seen in 25% of FSV, 50% of PSV and 33% of ITA. 5. A II caused concentration dependent contractions in all rings, over the same concentration range (1 nM-100 nM). In rings of FSV the presence of functional endothelium attenuated the response, median values with endothelium being less than half that without endothelium (P < 0.0007, at 100 nM).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2002

Early experience with robotically assisted internal thoracic artery harvest.

We sought to determine the efficacy of using robotic assistance to facilitate endoscopic harvesting of internal thoracic arteries (ITAs). A total of 104 patients had ITAs harvested endoscopically with use of both the AESOP 3000 system (Computer Motion, Goleta, CA, U.S.A.) and Zeus robotic telesurgical system (Computer Motion). All ITAs were harvested with a harmonic scalpel (Ethicon Endosurgery, Cincinnati, OH, U.S.A.). With the left lung collapsed, ITAs were harvested with CO2 insufflation through three 5-mm ports in the left chest. All patients tolerated insufflation without hemodynamic compromise. Average ITA harvest time was 61.3 +/- 20.9 minutes. Intraoperative graft flows averaged 36.3 +/- 22.4 mL/min. There were three distal ITA injuries; all other vessels were patent after harvesting and demonstrated no angiographic evidence of injury. This article demonstrates a technique by which ITA can be safely harvested totally endoscopically with use of computer-enhanced robotic systems and a harmonic scalpel, allowing complete pedicle dissection through 5-mm ports with minimal ITA manipulation.

Aged↗
PubMed1991

[Similarity between internal thoracic artery and gastroepiploic artery graft: pharmacological point of view].

The pharmacological responses of internal thoracic artery (ITA), gastroepiploic artery (GEA) and saphenous vein (SV) obtained from patients receiving coronary artery bypass grafting (CABG) were assessed by isometric contraction records. The concentration-response curves for ergonovine and serotonin showed the leftward shift in SV compared with ITA and GEA. The 50% effective dose values of SV for ergonovine and serotonin were significantly less than those of ITA and GEA. The concentration-response curves for phenylephrine were similar among three kinds of grafts. There were no significant differences in the 50% effective dose values for phenylephrine among them. The effect of 0.4% papaverine chloride on the free graft flow was assessed in 15 patients receiving CABG with mean body surface area of 1.62 +/- 0.12 M2. The free flow of ITA graft was 71 +/- 32 ml/min before intraluminal papaverine injection, and that increased to 112 +/- 41 ml/min after injection. The free flow of GEA graft was 82 +/- 39 ml/min before injection, and that also increased to 128 +/- 40 ml/min after injection. The patency rates at the mean 2.2 months after grafting were 98% in ITA, 93% in GEA, and 88% in SV. In conclusion, both GEA graft and ITA graft can be expected as an excellent conduit in myocardial revascularization.

Adult↗
PubMed1998

Left anterior descending endarterectomy and internal thoracic artery bypass for diffuse coronary disease.

BACKGROUND: The risk and efficacy of using an arterial conduit to bypass an endarterectomized coronary artery remain incompletely defined. To address this question we analyzed retrospectively 74 patients from 1989 to 1994 in whom bypass grafting using the left internal thoracic artery to an endarterectomized left anterior descending artery was performed. METHODS: There were 60 men and 14 women with a mean age of 60.1 +/- 8.6 years. Of this cohort, 55 patients (74.3%) had a previous infarction, 18 (24.3%) were diabetic, and 5 (6.7%) had reoperations; 25 patients (34%) had a totally occluded left anterior descending artery and the average ejection fraction was 45%. Each patient had 2.95 +/- 0.52 grafts with 48 patients (65%) requiring multiple endarterectomies. The average length of the endarterectomized segment was 3.1 +/- 1.6 cm. Average anoxia time was 49 +/- 13 minutes. Postoperatively 19 patients (25.6%) required intraaortic balloon and 18 (24.3%) required inotropic support. Perioperative infarction in the left anterior descending artery distribution occurred in 5 patients (6.7%). RESULTS: There were 3 (4.0%) early and 4 (5.4%) late deaths at a mean follow-up of 36 +/- 16 months. Recurrent angina was present in 9 patients (14.7%). Actuarial 5-year survival was 84.5%. Angiographic follow-up obtained in 23 patients (37.4%) demonstrated 74% anastomotic patency, with good distal run-off in 13 (65%). The anterior segmental wall motion was preserved. CONCLUSIONS: The use of the left internal thoracic artery bypass and adjunctive left anterior descending artery endarterectomy to expand the scope of myocardial revascularization in carefully selected circumstances appears to be beneficial.

Coronary Artery Bypass↗
PubMed1994

Cardiac reoperation in patients with bilateral internal thoracic artery grafts.

The superior long-term patency of the left internal thoracic artery (ITA) graft is reflected in the enhanced survival of the patients who undergo the procedure, and its use has been shown to lead to a reduced need for reoperation. Evidence is accumulating that use of both ITAs at the primary operation further decreases the need for reoperation, and it is hoped that the use of other arterial conduits will augment this trend. Therefore, the popularity of bilateral ITAs and other arterial conduits in coronary artery operations is growing. However, many surgeons defer using both ITAs at the primary operation partly out of fear of the difficulties that may arise in conjunction with a possible future reoperation. Thirty-six patients underwent reoperation at The Cleveland Clinic Foundation 2 days to 13 years after an earlier bilateral ITA operation because of the progression of native disease, failure of the ITA or vein grafts, or the development of valve disease or end-stage ischemic heart disease. There were four early deaths (11%) and two late deaths, with an average follow-up of 4.3 years (range, 0 to 9.8 years). Forty-seven ITAs were patent preoperatively and 11 crossed the midline. Eleven were patent but stenosed and in need of revision or replacement. Two were damaged during reoperation; both were repaired, but one was ultimately replaced. Although the mortality associated with this procedure is relatively high and these operations are difficult, reoperation can be performed at an acceptable risk, and substantial surgical objectives can be achieved with good long-term results.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed2003

Gelatin sheet incorporating basic fibroblast growth factor enhances sternal healing after harvesting bilateral internal thoracic arteries.

OBJECTIVE: We previously reported that a gelatin sheet incorporating basic fibroblast growth factor accelerated sternal healing after bilateral internal thoracic artery removal in normal and diabetic rats. The aim of this study was to evaluate the effects of this therapeutic modality on sternal healing in a large-animal model before performing a clinical trial. METHODS: After median sternotomy and bilateral internal thoracic artery removal in a pedicled fashion, 14 beagle dogs received either a gelatin sheet incorporating basic fibroblast growth factor (100 mug per sheet) on the posterior table of the sternum (FGF group, n = 7) or did not receive a gelatin sheet (control, n = 7). We compared sternal healing 4 weeks after surgical intervention between the groups. RESULTS: Scintigraphic images obtained by using technetium 99 methylene diphosphonate bone scanning were assessed visually, and the impulse rate was quantified 30 and 60 minutes after injection of technetium 99 methylene diphosphonate to evaluate the sternal perfusion. Sternal uptake was significantly increased in the FGF group (30 minutes: 221% +/- 30% vs 180% +/- 36%; 60 minutes: 267% +/- 26% vs 197% +/- 42%; P <.01). Apparent sternal dehiscence, as assessed radiographically, was observed only in the control animals. Histologically, complete healing of the sternum with marked angiogenesis was observed in the FGF group, whereas poor healing with limited angiogenesis was seen in the control animals. Both bone mineral content (134 +/- 49 vs 52 +/- 32 mg, P <.01) and bone mineral density (133 +/- 53 vs 66 +/- 32 mg/mm(2), P <.05) along the incision line of the sternum, as assessed by means of dual-energy x-ray absorptometry, were higher in the FGF group. CONCLUSIONS: A gelatin sheet incorporating basic fibroblast growth factor enhances sternal perfusion and accelerates sternal bone healing in large animals.23

Animals↗
PubMed2006

Protecting the crossover right internal thoracic artery bypass graft with a pedicled thymus flap.

The right internal thoracic artery graft is placed in jeopardy during repeat sternotomy as it crosses the aorta anteriorly to reach its left-sided coronary targets. We have devised a way of protecting it by means of a pedicled flap taken from the thymic remnants. The flap is easily developed without unduly increasing operative time and morbidity, and it is expected to prevent inadvertent injuries to the graft in the case of mediastinal reentry. Starting in 1999, suitable flaps were obtained in 955 of 1,034 patients (92.4%) receiving an anteaortic crossover right internal thoracic artery-to-coronary graft in our division.

Humans↗