Anatomic variability of rejection in intestinal allografts after pediatric intestinal transplantation

The internal mammary artery is routinely used for coronary artery bypass grafting because of its optimal long-term patency profile. This vessel can be imaged by angiography, but only the proximal tract at the origin from the succlavian artery can be imaged by conventional echography. The aim of our study was to visualize the intrathoracic course of the native and grafted internal mammary arteries by a new ultrasound equipment which allows high-resolution transthoracic color Doppler imaging of the chest wall vessels and coronary arteries. We studied 35 patients, 16 non operated and 19 operated of coronary surgery with the internal mammary artery grafted to the left anterior descending coronary artery. We used a multifrequency 3.5-7 MHz transducer with a small insonating surface, placed at the second-fifth intercostal space at the left and right sternal border, to image the native mammary arteries. The grafted mammary artery was detected at the fourth-fifth left intercostal space 2-4 cm lateral to the sternal border. The native left internal mammary artery was visualized in all 16 non operated patients, and the right internal mammary artery in 14/16 (87%). The native left internal mammary artery peak flow velocity was 41-160 cm/s (mean 81 +/- 34 cm/s), and the mean flow velocity was 28-89 cm/s (mean 45 +/- 17 cm/s). The right internal mammary artery peak flow velocity was 35-153 cm/s (mean 82 +/- 36 cm/s), and mean flow velocity was 21-82 cm/s (mean 46 +/- 22 cm/s). The grafted left internal mammary artery was visualized in 16/19 patients (84%), evaluated at 6 days to 36 months after surgery. Peak diastolic flow velocity ranged from 24 to 80 cm/s (mean 48 +/- 17 cm/s), and mean diastolic flow velocity ranged from 13 to 57 cm/s (mean 33 +/- 11 cm/s). The left anterior descending peak flow velocity distal to the anastomosis was 22-62 cm/s (mean 37 +/- 15 cm/s) and mean flow velocity was 18-53 cm/s (mean 29 +/- 12 cm/s). We conclude that transthoracic color Doppler echocardiography allows to image the native and grafted mammary arteries, with potential clinical applications in the management of patients with coronary artery disease.     

Complete direct mammary harvest for minimally invasive coronary artery bypass

Minimally invasive coronary artery bypass has primarily involved left internal mammary artery grafting to the left anterior descending coronary artery through a small left anterior thoracotomy incision. Harvesting of the mammary artery has been accomplished completely using a video-assisted thoracoscopic technique or incompletely to the second interspace under direct vision. With a mammary retractor, the mammary artery can be dissected completely under direct vision, thus eliminating any criticism of an incomplete harvest and any increased difficulty or expense associated with the thoracoscopic harvest. In this series, all 17 mammary arteries were successfully harvested completely under direct vision and 16 patients underwent successful minimally invasive coronary bypass.     

Comparative reactivity and mechanical properties of human isolated internal mammary and radial arteries

OBJECTIVE: The aim of this study was to analyse the arterial wall mechanics and the vasoreactive properties of the radial artery in comparison with those of the internal mammary artery and to discuss their implications for coronary bypass grafts. METHODS: Measurements of pressure and diameter were obtained from cylindrical segments, whereas measurements of reactivity were obtained from ring segments from the same arteries. We used an echo-tracking technique of high resolution enabling to investigate, in vitro, the diameter and the wall thickness of arterial cylindrical segments. Furthermore, the compliance, distensibility and incremental elastic modulus of the radial and of the mammary arteries were determined for a wide range of transmural pressure (0-200 mmHg) in presence and absence of norepinephrine (NE). RESULTS: Our results show that NE caused vasoconstriction of the two arteries. Strain was found significantly higher for the radial artery than for the internal mammary artery at any given value of stress both in the presence and in the absence of NE. In presence of NE, compliance for radial artery, in the overall transmural pressure range, did not change, whereas, distensibility was significantly increased and the elastic modulus was significantly decreased. Under the same conditions, the distensibility of the mammary artery tended to decrease and its elastic modulus to increase. In parallel, the vasoreactive properties of the two arteries confirmed the previous results showing that radial artery developed a significant higher tension to vasoconstricting agents (KCl, NE and phenylephrine (PHE)) and higher relaxation to isradipine than internal mammary artery. Moreover, radial artery displayed a lesser sensitivity to sodium nitroprusside than internal mammary artery. Furthermore, sensitivity to NE was found to be 7-fold higher for radial artery than for internal mammary artery. CONCLUSION: Taken together, data on the mechanical and reactive properties of radial and internal mammary arteries show why the radial artery displayed a higher potential for spasm than the internal mammary artery and why the use of Ca2+ channel blocker can decrease the incidence of occlusion and spasm.     

Cardiac revascularization using both mammary arteries

Both internal mammary arteries in combination with veins were used for revascularization of the hearth in fifty Danish patients undergoing coronary artery bypass grafting (CABG) at Gentofte Hospital during the period 1994-1996. Patients with insulin-dependent diabetes mellitus, obesity, and age over 75 years were excluded. The patients were followed for at least one month after the operation. No patients died, and the complication rate was low and comparable to standard CABG using the left mammary artery and vein grafts. It is known from the literature that 10 years after CABG only 50% of vein grafts remain patent, and half of these have severe atherosclerosis. The mammary artery is far more resistant to atherosclerosis and 15 years after the procedure fewer patients have recurrent angina when both mammary arteries have been used. Bilateral mammary artery grafts can be used in half of CABG-procedures, and are especially indicated in younger patients.     

Value of reversed saphenous vein in minimally invasive direct coronary artery bypass graft procedures

BACKGROUND: Minimally invasive direct coronary artery bypass graft procedures are gaining acceptance for revision as well as primary coronary revascularization. When suitable, the left and right internal mammary arteries are preferred as bypass conduits; in other cases, the greater saphenous vein, used for standard coronary artery bypass graft procedures, may be useful to revascularize coronary artery branches during minimally invasive direct coronary artery bypass graft procedures. METHODS: We used the greater saphenous vein on three occasions during minimally invasive direct coronary artery bypass graft procedures (1) to revascularize the left anterior descending coronary artery by anastomosis to the left axillary artery in the infraclavicular region, (2) as an extension to the left internal mammary artery to reach the left anterior descending coronary artery, and (3) as a bridge from the splenic artery to bypass the distal right coronary artery. RESULTS: Postoperatively, all 3 patients had relief from symptoms of coronary artery insufficiency and none has been readmitted to the hospital with symptoms. Angiography or thallium studies were not performed to confirm graft patency because all patients were elderly and the risks of these procedures were considered to outweigh their potential benefit. CONCLUSIONS: The greater saphenous vein is a potential bypass conduit for use in minimally invasive direct coronary artery bypass graft procedures as well as for coronary artery bypass graft procedures.     

Ultrasonographic evaluation of the anterior recess in the normal hip: a prospective study on 166 asymptomatic children

Bypass graft patency with ultrafast computed tomography (= Electron Beam Tomography, EBT) was examined in 72 bypass grafts (47 saphenous veins, 25 internal mammary arteries) in 30 patients and compared with coronary angiography. Angiography was performed a mean of 4.4 +/- 3.5 months (range 1-13) from the EBT examination. Contrast material (120 ml) was continuously administered via a peripheral vein and 40 axial slices (3 mm slice thickness, 110 ms scan time) without overlap sequences were obtained, ECG triggered with the single slice scanner mode. Imaging of internal mammary artery grafts began at the thoracic inlet, for saphenous vein grafts, at the undersurface of the aorta. Sixty of 63 angiographically patent bypass grafts were determined patent by EBT (sensitivity 95%), 8 bypass grafts could not be detected by EBT, and 9 were angiographically occluded (specificity 89%). Twenty-four of 25 internal mammary artery grafts were patent at EBT and coronary angiography, one was occluded. In 27 of the 30 patients (90%), all of the angiographically patent grafts could be confirmed as open with EBT. Obstructions of 10 grafts could not be visualized with EBT. Graft insertion into native coronary vessels could be visualized in axial slices, although morphologic quantification of graft insertion stenosis (75-90%) in two cases was not possible. Three dimensional reconstruction of the 40 axial slices allowed graft anatomy to be delineated. Visualization of bypass insertion into the native coronary vessel was less successful because of opacification of the left and right ventricle. Electron beam computed tomography is a minimally invasive procedure capable of evaluating the patency of saphenous vein and internal mammary artery grafts. The morphologic quantification of graft obstruction and visualization of the insertion of the bypasses into the native coronary vessels is less successful with present technology and imaging modalities.     

The internal mammary artery 'string phenomenon'. Analysis of 10 cases

The internal mammary artery (IMA) string sign has been described as a narrowing of IMA grafts in the late course after coronary artery bypass grafting. It has been assumed that this phenomenon was due to competitive flow in grafts connected to only mildly stenosed coronary arteries. We analyzed 10 cases of IMA string sign operated on between March 1988 and June 1991. Bilateral IMA was used in six cases and unilateral IMA in four. The mean interval between operation and reangiography was 14 +/- 11 months. String sign of the whole length of the IMA was detected in nine cases, and of the distal part between two sequential anastomoses in one. In all cases, the stenosis of the vessel bypassed with the narrowed graft proved to be only mild (50% or less) at reangiography. In all six cases with bilateral IMA grafts, the contralateral IMA was widely patent. These were all connected to highly stenosed or occluded coronary arteries. With respect to this observation, there is a high index of suspicion that the string phenomenon occurs due to competitive flow in only mildly stenosed coronary arteries. We decided, for our strategy in coronary artery surgery, still to aim at complete revascularization using IMAs as much as possible, but to avoid connecting IMA grafts to only mildly or moderately stenosed coronary arteries.     

A case of de novo translocation 16;21: trisomy 16q phenotype and origin of the aberration

We reviewed our experience over a 12 month period with using minimally invasive direct coronary artery bypass (MIDCAB) for the management of high-risk patients with three-vessel coronary artery disease. Twenty patients (4 females, mean age 67 years) received left internal mammary artery (LIMA) grafts to the left anterior descending (LAD) coronary artery. Associated co-morbidity included: severe chronic renal failure, severe extensive arteriopathy, chronic obstructive airway disease, poor general condition and severely impaired left ventricular function. There was one early postoperative mortality and no other cardiac-related morbidity. Graft patency investigated, using angiography was 90%, and 5 patients underwent follow-up angioplasty to other coronary arteries. All patients remain entirely angina free at a follow-up period between 3 and 12 months. We conclude that MIDCAB is a safe and effective approach for managing high-risk patients with three-vessel coronary artery disease.     

Office hysteroscopy versus transvaginal ultrasonography in the evaluation of patients with excessive uterine bleeding

Successful treatment of a severe haemoptysis with microcoil embolization in an en block double-lung transplanted patient is described. A 53 year old woman with advanced bronchiolitis obliterans syndrome experienced severe haemoptysis 26 months after an en bloc double-lung transplantation with direct bronchial artery revascularization using the left internal mammary artery. Bronchoscopy showed that the haemoptysis originated from the lingula. Only two months after the transplant, left internal mammary arteriograms revealed proliferation and enlargement of the bronchial arteries in the lingula. The early occurrence of the vascular malformation indicated a pre-existing bronchiectasis in the donor lung, possibly due to tobacco smoking. After uncomplicated microcoil embolization of the left internal mammary artery, the patient experienced no further episodes of haemoptysis. Microcoil embolization can be used successfully to treat massive haemoptysis related to proliferated and enlarged bronchial arteries in transplanted lungs with bronchial artery revascularization.     

Comparison of the morphologic and vascular reactivity of the proximal and distal radial artery

BACKGROUND: Variations in the morphology and vascular reactivity of the proximal and distal radial artery might influence its performance as a bypass conduit. METHODS: The morphologic and functional characteristics of the proximal and distal RAs were compared with those of the left and right internal mammary arteries by using histologic and in vitro organ bath techniques. RESULTS: Proximal RA had a significantly greater medial cross-sectional area compared with that of the distal RA (2.48+/-0.27 mm2 compared with 1.86+/-0.21 mm2, p< 0.05), which were both significantly greater than the left internal mammary artery (0.54+/-0.09 mm2) or the right internal mammary artery (0.67+/-0.03 mm2). Proximal RA had a significantly greater response to 90 mmol/L potassium chloride than that of distal RA (88.4+/-7.3 compared with 60.2+/-10.3 mN, p<0.05), and both contracted more than the left internal mammary artery (30.3+/-2.9 mN) and the right internal mammary artery (32.6+/-4.1 mN). There was no difference in the response to noradrenaline and adrenaline between proximal and distal RA, both of which contracted more than the left and right internal mammary arteries. CONCLUSIONS: When choosing a segment of RA for use as a bypass conduit, regional variations in biologic properties should be considered.     

Internal mammary vein to coronary artery anastomotic fistula

Two patients are presented where internal mammary artery grafting was performed for the relief of symptomatic coronary artery disease. At follow-up the internal mammary artery was occluded and a communication between the internal mammary vein and the native coronary artery was demonstrated. These patients were characterised by the early recurrence of angina or the appearance of a continuous murmur. Both patients were treated by re-operation with ligation of the arterio-venous fistula and saphenous vein grafting.     

Minimally invasive coronary artery bypass grafting: port-access approach versus off-pump techniques

BACKGROUND: Within the past 5 years several surgical techniques have been developed for less invasive surgical treatment of coronary artery disease. The aim of this study was to define specific indications for the various minimally invasive coronary artery surgical procedures. METHODS: Minimally invasive direct coronary artery bypass grafting through a minithoracotomy was performed in 67 patients. The left internal mammary artery was anastomosed on the beating heart with the use of a pressure or suction stabilizer without the use of extracorporeal circulation. In 58 other patients with multivessel disease, the off-pump coronary artery bypass grafting technique through a sternotomy was applied with a left internal mammary artery to left anterior descending artery and additional vein grafts without extracorporeal circulation. In a third group, Port-Access (Heartport Inc, Redwood City, CA) coronary artery bypass grafting was performed through a left minithoracotomy with the use of an endovascular extracorporeal circulation system and cardioplegic arrest. Angiographic follow-up was complete in 64% of the patients. RESULTS: There was minimal perioperative or postoperative mortality (0.5%). The medium surgical procedure time for all minimally invasive and off-pump procedures was 2.5 hours; it was 4.5 hours for Port-Access procedures. The median postoperative intensive care unit stay was 1.0 days, and the median hospitalization was 5.0 days. Overall graft patency was 97.3%; in 8 patients (4.1%) a stenosis either at or distal to the graft anastomosis was dilated with coronary angioplasty. CONCLUSIONS: For single-vessel disease of the left anterior descending artery, the minimally invasive coronary artery bypass grafting procedure can be performed safely without the use of extracorporeal circulation. In case of hemodynamic instability or anatomic variation, the Port-Access procedure can be applied without additional necessity for sternotomy. For multivessel disease, the off-pump bypass grafting procedure with sternotomy can be recommended depending on the coronary arteries involved. In case of necessary grafts to the lateral marginal or circumflex branches, Port-Access grafting can be recommended and may play an important role in the future for the development of fully endoscopic robot-assisted coronary artery bypass grafting.     

Breast infarction after internal mammary artery harvest in a patient with calciphylaxis

The use of the internal mammary artery during coronary artery bypass grafting is commonplace. Complications associated with the harvest of the internal mammary artery have predominantly been wound related. These range from skin dehiscence to complete avascular necrosis of the sternum. This report documents complete ischemic necrosis of a breast in a patient with end-stage renal disease and a history of calciphylaxis, after the harvest of an internal mammary artery.     

Study of the coronary flow with high resolution transthoracic echocardiography and nondirectional Doppler

Two-dimensional echocardiography allows to evaluate the effect of myocardial ischemia on left ventricular wall motion, but a direct measure of coronary flow by this method is still lacking. The aim of the present study was to evaluate the efficacy of a new, high-resolution echocardiographic equipment designed to image the epicardial and intramural coronary vessels by non directional Doppler. We studied 33 consecutive patients by transthoracic echocardiography in apical projections, to detect one or more segments of the left anterior descending coronary artery by non directional Doppler. Once the coronary artery has been imaged, pulsed Doppler was used to measure coronary blood flow velocity at rest. Peak and mean flow velocities were measured on the diastolic phase of the Doppler spectrum. In 25/33 patients (75.7%) the middle-distal tract of the left anterior descending coronary artery was imaged by non directional Doppler. In 15/33 patients (45.5%) the periapical tract of the left anterior descending coronary artery was imaged along with its perforating branches. In 2 out of 4 patients operated of coronary artery bypass grafting, the anastomosis between the left internal mammary artery and the left anterior descending coronary artery was imaged. In all 25 patients it was possible to measure by pulsed Doppler the coronary velocity flow pattern, characterized by a typical prevalent diastolic component. Peak diastolic flow velocity was 49.98 +/- 17.30 cm/s and mean diastolic flow velocity was 36.52 +/- 11.91 cm/s. The Doppler pattern of the grafted mammary artery was different from the native mammary flow. This new non invasive imaging technique of the coronary arteries promises to expand the field of diagnostic and experimental echocardiography and brings new insight into the pathophysiology of ischemic heart disease.     

Atherosclerosis of the inferior epigastric and internal mammary arteries

Atherosclerosis of the inferior epigastric artery (IEA) and the internal mammary artery (IMA) was evaluated in 21 patients with coronary heart disease. Both arteries were used simultaneously in coronary artery bypass grafting. Histologic samples were obtained from the proximal and distal segments of IEA and from the distal segment of IMA. Morphologic findings in regard to atherosclerosis were classified semiquantitatively as normal (0), or luminal narrowing <25% (1), 25-50% (2) or >50% (3), or as overt atherosclerosis and calcification (4). Atherosclerosis was absent or minimal (1) in distal samples from both arteries. Only one IMA showed moderate (2) luminal atherosclerotic obstruction. Two samples from proximal IEA showed moderate (2) or severe (4) atherosclerotic changes which limited their use as free grafts. These finding suggest that atherosclerosis is minimal and comparable in distal IEA and IMA in their natural environments even in patients with coronary heart disease. The long-term effect of aortic pressure on free IEA graft is still unclear.     

Reoperative coronary bypass grafting without cardiopulmonary bypass through a small thoracotomy

BACKGROUND: The danger of coronary reoperations is mainly hidden in the reopening of the sternum and in the manipulation of the heart and the old grafts. Therefore, the minimally invasive direct coronary artery bypass procedure seems an ideal technique for coronary reoperations if only the left anterior descending coronary artery needs to be revascularized and the left internal mammary artery has not been used previously. METHOD: From January 1995 until May 1996 we performed 81 minimally invasive direct coronary artery bypass procedures through a small anterolateral thoracotomy in the fifth intercostal space, anastomosing the left internal mammary artery to the left anterior descending coronary artery. Six of these 81 were reoperative minimally invasive direct coronary artery bypass procedures on patients who had previously undergone coronary grafting through a median sternotomy with a vein graft to the left anterior descending coronary artery. RESULTS: Mean operation time was 85.8 +/- 22.2 minutes. Mean length of the mammary pedicles was 13 +/- 2 cm. Mean coronary occlusion time was 9.2 +/- 3.2 minutes. Mean postoperative hospital stay was 5.7 +/- 1.2 days (range, 5 to 8 days). No mortality and no cardiac-related morbidity were recorded. CONCLUSIONS: These results suggest that the technique is safe and promising in selected cases of reoperative coronary operation.     

Coronary steal through anomalous internal mammary artery graft. Treated by ligation without sternotomy

A patient who had undergone adequate coronary revascularization with a left internal mammary artery graft to the left anterior descending coronary artery and with saphenous vein grafts to the right coronary artery and to the 1st and 2nd obtuse marginal branches presented with early-onset recurrent angina. A repeat angiogram showed an abnormally large branch arising from the very proximal segment of the left internal mammary artery and supplying the whole lateral chest wall via many intercostal tributaries. Relief of symptoms was achieved by ligation of this branch, and the patient remains symptom free more than 6 years after the procedure.     

Maximal utilization of the left internal mammary artery for coronary bypass grafting

A technique is described for using the internal mammary artery to bypass the left anterior descending coronary artery and another adjacent coronary artery even when the alignment of the two vessels is not favorable for a conventional sequential graft. The distal end of the mammary artery is amputated and used to construct a Y graft to the anterior descending artery and to the secondary target vessel.     

Intraoperative "direct" LIMA angiography for beating heart operations

The importance of the angiographic assessment of coronary bypass grafts performed on the beating heart has been recognized. We describe a simple technique for intraoperative angiography of left internal mammary artery to left anterior descending coronary artery grafts that does not require selective left internal mammary artery catheterization. This method allows immediate appraisal of the graft, hence enabling the surgeon to revise any graft or anastomosis abnormality immediately and to verify optimal results of beating heart operations.     

Angina caused by subclavian-coronary steal in patients revascularized with internal mammary artery]

After coronary bypass surgery in the left internal mammary artery, occlusive atherosclerosis in the proximal subclavian artery can produce reverse flow in the mammary artery and myocardial ischemia (coronary-subclavian steal syndrome). This is a rare cause of recurrent myocardial ischemia. We present two patients with postoperative complete obstruction in the proximal subclavian artery and inverse flow in the mammary artery producing severe ischemia in the left anterior descending artery territory. Both patients were treated with subclavian-subclavian bypass, which in one patient was ineffective in producing an adequate anterograde flow in the left internal mammary artery. We review clinical management, diagnostic methods and therapeutic options used in the coronary-subclavian steal syndrome.