Mammary Artery Research Articles

Bilateral MIDCAB for triple vessel coronary disease

Minimally invasive direct coronary artery bypass grafting utilising an anterior mini-thoracotomy has traditionally been limited to surgical revascularisation for single or double vessel coronary disease. The widespread use of percutaneous coronary intervention has further limited the use of this technique. Minimally invasive direct coronary artery bypass grafting offers the advantage of avoiding a sternotomy, in patients with a higher risk of sternal wound dehiscence and infection. We have used bilateral anterior mini-thoracotomy in conjunction with bilateral internal mammary and radial artery conduits, allowing an aortic no-touch technique, on the off-pump heart in two patients.

Sternal Nourishment in Various Conditions of Vascularization

Early changes in sternal perfusion were studied after midline sternotomy and different methods of mammary artery (MA) harvesting. Our observations were made in the swine model after midline sternotomy. In group 1 (6 animals), after unilateral skeletonized MA harvesting, (99m)Tc particles were injected intravenously. In group 2 (7 animals), after unilateral mammary artery and vein harvesting (semiskeletonized technique), (99m)Tc particles were injected intravenously. In group 3 (5 animals), after skeletonized bilateral MA harvesting, 99mTc particles were injected into the intercostal musculature lateral to the sternal border. In groups 1 to 3, sternal samples were analyzed using gamma counting. In group 4 (6 animals), unilateral skeletonized MA harvesting was performed. In group 5 (5 animals), the MA was harvested unilaterally using the semiskeletonized technique. In groups 4 and 5, sternal blood flow was assessed using thermography. Data were collected in all groups for 5 hours postoperatively. Both radioactive and thermographic flow measurements showed a statistically significant decrease in sternal blood flow on the side of harvested mammary vessels, regardless of harvesting technique. Radioactivity of the devascularized hemisterni on the side of intramuscular particle injection was substantially higher than in the contralateral half, confirming the role of diffusion in sternal nourishment. The distal sternal segments were least perfused by the MA. There is an acute reduction of sternal perfusion during the early postoperative period, even if collaterals are preserved by skeletonized MA harvesting. Diffusion plays an important role in sternal nourishment, particularly of the xiphoid, and even more so after MA harvesting.

Animal Model of Cerebral Ischemia

Cerebral ischemia is a complex and mutifactorial process. Animal models of cerebral ischemia have been widely used to make clear the pathophysiology of the ischemic brain injury and to test the therapies against cerebral ischemia. Many animal ischemia models have been developed in numerous species and in various forms of cerebral ischemia, namely global and focal, complete and incomplete, and permanent and transient. In global cerebral ischemia, selective cell vulnerability to ischemia is a most important factor. Neurons appear to be more susceptible to hyoxia and ischemia as compared with other components, such as glial cells and vessels. In global cerebral ischemia models, the global cerebro-circulatory arrest model by occluding the inominate, the left subclavian and both mammary arteries, the bilateral carotid occlusion with systemic hypotension model in rats, the 4 vessel occlusion model in rats, and the bilateral carotid occlusion model were decribed in here. On the other hand, the main issue in the focal cerebral ischemia is a concept of ischemic thresholds of cerebral blood flow. The so-called of ischemic penumbra is of particular interest as a zone of nonfunctioning but still viable tissue that may recover its function if blood flow can be restored. As the focal cerebral ischemia model, the middle cerebral artery occlusion model in cats and rats and the embolic stroke model were discussed in here.

Access Denied; Care Impaired: The Benefits of Having Online Medical Information Available at the Point-of-Care

The availability of Internet-enabled computers in the operating room (OR) facilitates unparalleled physician access to current peer reviewed research, either in abstract or full text format, a development that provides physicians with an exciting opportunity to incorporate such findings into clinical practice at the point-of-care. In this report I describe how the availability of online peer reviewed medical literature altered, in one case a planned surgical procedure and, in the other, the interpretation by the anesthesiologist of the clinical significance of an intraoperative echocardiographic finding. In case one, a free, rather than an intact, internal mammary (IM) artery graft was placed to the left anterior descending coronary artery of a patient with renal failure and an ipsilateral upper extremity arteriovenous fistula. The change occurred after the full text results of a study indicating that steal could well occur during the initiation of dialysis if an intact IM was used were made available to the surgeon. In case two, the occurrence of mild central mitral regurgitation in a Carpentier-Edwards Perimount prosthetic mitral valve was confirmed to be a benign finding after a study detailing the long term performance characteristics of this valve was accessed online in the OR. The benefits and potential pitfalls of searching and interpreting online medical information are discussed.

Mid-term angiographic results of radial artery (RA) graft in CABG: Does the proximal site of anastomosis affect graft patency?

Use of arterial conduits in coronary artery bypass grafting (CABG) is based on the documented excellent patency rates of left internal thoracic (mammary) artery (LITA). Alternative arterial conduits such as radial artery and gastroepiploic artery also showed superior long-term patency rates compared to vein grafts. Free arterial grafts are being used increasingly to replace the long saphenous vein as a conduit. This study was undertaken to compare two methods of radial artery grafting as a free graft and a composite graft. Between January 1997 and October 2003 a total of 441 patients were operated for coronary artery bypass grafting using radial artery (RA) as one of the conduits. Among these patients, 125 patients received radial artery as a composite graft; In 68 patients RA was used with left internal thoracic artery as a composite y graft (n=68), and in 57 patients it was used with right internal thoracic artery (RITA) as an in situ composite pedicle graft (n=57). In the remaining 316 patients the radial artery was used as a free graft. Angiographic evaluation of radial artery graft was carried out in 63 patients who consented. Angiograms were carried out after an interval of 6–72 months (mean of 28.15±21.17 months). Of these 63 patients who underwent reangiography, the different surgical strategies used were RITA+RA composite in situ graft (n=34), LITA+RA composite y graft (n=17) and aorto coronary (free) RA graft (n=12). There were 3 hospital deaths in the series 441 patients. Among the 63 patients who underwent check angiography 60 patients were in NYHA C1 I and 3 patients were in C1 II. None of the patients had perioperative myocardial infarction. Angiographically overall radial artery graft patency rate was 94.1% (59 patients). In patients with RITA and RA in situ grafts patency rate was 94.1%, LITA+RA composite y graft patency was 94.1% and aorto coronary (free) radial artery grafts patency was 91.6%. In 63 selected asymptomatic patients studied, we found that radial artery graft when used as an aortocoronary (free) graft or as a composite y graft with left internal thoracic artery or in situ pedicle graft with right internal thoracic artery the patency rates were comparable in all three groups.

Reactive oxygen species induce RNA damage in human atherosclerosis.

Reactive oxygen species (ROS)-induced DNA damage has recently been identified in both human and experimental atherosclerosis. This study was undertaken to investigate whether RNA damage occurs in human atherosclerotic plaques and whether this could be related to oxidative stress. The integrity of total RNA isolated from carotid endarterectomy specimens (n = 20) and nonatherosclerotic mammary arteries (n = 20) was analyzed using an Agilent 2100 Bioanalyser (Agilent Technologies, Palo Alto, CA). Oxidative modifications of RNA were detected by immunohistochemistry. Eleven out of 20 atherosclerotic plaques showed a significant reduction of the 18S/28S rRNA peaks and a shift in the RNA electropherogram to shorter fragment sizes. In contrast, all mammary arteries showed good-quality RNA with clear 18S and 28S rRNA peaks. Strong nuclear and cytoplasmic immunoreactivity for oxidative damage marker 7,8-dihydro-8-oxo-2'-guanosine (8-oxoG) could be detected in the entire plaque in smooth muscle cells (SMCs), macrophages and endothelial cells, but not in SMCs of adjacent normal media or in mammary arteries. Cytoplasmic 8-oxoG staining in the plaque clearly diminished when tissue sections were pretreated with RNase A, suggesting oxidative base damage of RNA. In vitro treatment of total RNA with ROS-releasing compounds induced RNA degradation. Both loss of RNA integrity and 8-oxoG oxidative modifications were found in human atherosclerotic plaques. Because RNA damage may affect in vitro transcript quantification, RT-PCR results must be interpreted cautiously if independent experimental validation (e.g. evaluation of RNA integrity) is lacking.

Letter to the Editor

To the Editor: The −786C allele in the promoter, but not the Asp298 (894T) variant in exon 7, of the endothelial nitric oxide synthase (NOS3) gene has been recently associated with a blunted increase in blood flow average peak velocity induced by acetylcholine in coronary or mammary artery after a 4-week exercise training program.1 By providing a potential explanation for the remarkable individual heterogeneity of responses achieved with exercise in coronary artery disease (CAD) patients, these results extend previous landmark findings from this group.2 The authors carefully excluded patients with arterial hypertension, insulin-dependent diabetes mellitus, smoking, and hypercholesterolemia, eg, conditions that notoriously induce endothelial dysfunction. However, …

Electrophysiological evaluation of phrenic nerve injury during cardiac surgery – a prospective, controlled, clinical study

BackgroundAccording to some reports, left hemidiaphragmatic paralysis due to phrenic nerve injury may occur following cardiac surgery. The purpose of this study was to document the effects on phrenic nerve injury of whole body hypothermia, use of ice-slush around the heart and mammary artery harvesting.MethodsElectrophysiology of phrenic nerves was studied bilaterally in 78 subjects before and three weeks after cardiac or peripheral vascular surgery. In 49 patients, coronary artery bypass grafting (CABG) and heart valve replacement with moderate hypothermic (mean 28°C) cardiopulmonary bypass (CPB) were performed. In the other 29, CABG with beating heart was performed, or, in several cases, peripheral vascular surgery with normothermia.ResultsIn all patients, measurements of bilateral phrenic nerve function were within normal limits before surgery. Three weeks after surgery, left phrenic nerve function was absent in five patients in the CPB and hypothermia group (3 in CABG and 2 in valve replacement). No phrenic nerve dysfunction was observed after surgery in the CABG with beating heart (no CPB) or the peripheral vascular groups. Except in the five patients with left phrenic nerve paralysis, mean phrenic nerve conduction latency time (ms) and amplitude (mV) did not differ statistically before and after surgery in either group (p > 0.05).ConclusionsOur results indicate that CPB with hypothermia and local ice-slush application around the heart play a role in phrenic nerve injury following cardiac surgery. Furthermore, phrenic nerve injury during cardiac surgery occurred in 10.2 % of our patients (CABG with CPB plus valve surgery).

395 Comparision of the morphological and functional characteristics of internal mammary arterym radial artery and venous saphenous grafts

395 Comparision of the morphological and functional characteristics of internal mammary arterym radial artery and venous saphenous grafts

Off-pump coronary bypass surgery for left main coronary artery stenosis 10 years after heart transplantation: case report

A patient with asymptomatic left main coronary artery stenosis 10 years after heart transplantation was treated successfully with off-pump coronary bypass surgery using both mammary arteries. New advances in bypass surgery may decrease the risk of revascularization in cardiac transplant recipients.

Different expression of MMPs/TIMP-1 in human atherosclerotic lesions. Relation to plaque features and vascular bed

Background: Proteolytic imbalance might determine arterial remodeling and plaque destabilization in atherosclerotic vessels. The aim of this study was to examine differences in the patterns of metalloproteinases (MMPs) and MMP inhibitor (TIMP-1) expression in advanced human atheromas, both in relation to the plaque features and the vascular bed involved. Methods and results: Immunohistochemistry for MMP-1, -3, -9 and TIMP-1 as well as the collagen content were measured in vascular sections from patients undergoing peripheral revascularization (carotid n=11, femoral n=23) and aorto-coronary bypass surgery (mammary arteries n=20, as controls). Increased expression of all MMPs was detected in atherosclerotic as compared with control sections ( P<0.01). Aneurismal plaques showed a significant increase of MMP-1 and-3 and a reduction in total collagen ( P<0.05) in relation to occlusive lesions. Calcification areas in atherosclerotic plaques were consistently associated with increased TIMP-1 expression ( P<0.01). Finally, MMP-9 expression was higher in occlusive lesions from carotid than femoral arteries ( P<0.01). Conclusions: Aneurysm lesions expressed higher MMP-1 and-3 expression than occlusive plaques, and MMP-9 was mainly detected in carotid as compared with femoral arteries. TIMP-1 was associated with arterial calcification. These differences in the MMPs/TIMP-1 expression might determine the evolution of advanced atherosclerotic plaques and contribute to its vulnerability.

Estrogen selectively up-regulates eNOS and nNOS in reproductive arteries by transcriptional mechanisms.

To determine the mechanism(s) whereby daily and acute estradiol-17beta (E(2)beta) exposure modifies endothelium-derived nitric oxide synthase (eNOS) and vascular smooth muscle (VSM) neuronal nitric oxide synthase (nNOS) in reproductive and nonreproductive arteries and to localize NOS isoform expression within the vessel wall. Oophorectomized nonpregnant ewes received E(2)beta (1 microg/kg per day) or no E(2)beta for 5-6 days or acute E(2)beta (1 microg/kg) on day 6-7 with or without daily E(2)beta. Uterine, mammary, mesenteric, and femoral arteries were collected at completion of each study, adventitia were removed, and samples were frozen and stored at -80C. After separating endothelium and VSM, NOS isoform mRNA was measured using reverse transcription-polymerase chain reaction. VSM nNOS protein was determined by Western analysis. Basal eNOS and nNOS mRNA was greatest (P <.02) in reproductive artery endothelium and VSM, respectively. Daily E(2)beta was required for maximum uterine vascular responses to acute E(2)beta and was associated with increased reproductive artery endothelial eNOS mRNA (>1.5-fold, P <.02) and uterine VSM nNOS mRNA (>2.5-fold, P <.003) and protein (21%, P <.05). Acute E(2)beta in the presence and absence of daily E(2)beta also increased uterine eNOS 68% and 28% (P =.01), respectively, within 90 minutes but did not affect VSM nNOS. Mammary eNOS increased 71% only after E(2)beta withdrawal; VSM nNOS was unchanged. Neither NOS isoform was altered in nonreproductive arteries by daily or acute E(2)beta. Basal eNOS and nNOS isoform expression is greatest in arteries from reproductive tissues, and isoform responses to E(2)beta are cell specific and transcriptionally regulated. Furthermore, optimal uterine vascular responses to acute E(2)beta exposure require daily E(2)beta exposure that enhances basal NOS expression and abundance.

Overexpression of the Anti-Apoptotic Caspase-2 Short Isoform in Macrophage-Derived Foam Cells of Human Atherosclerotic Plaques

Apoptosis or programmed cell death is a cellular suicide mechanism that frequently occurs in advanced human atherosclerotic plaques. Caspases, a family of cysteine proteases, have been identified as important effectors of the death machinery. In this study, we report strong caspase-2 immunoreactivity in foam cells of macrophage-origin around the necrotic core of advanced human atherosclerotic plaques. In contrast, smooth muscle cells (SMCs) and macrophages in the fibrous cap as well as endothelial cells, medial SMCs, and SMCs from mammary arteries are negative for caspase-2. Caspase-2-positive macrophages were isolated from human plaques by laser capture microdissection and were then analyzed by Western blotting. A single band of approximately 35 kd corresponding with the precursor of the short, anti-apoptotic isoform of caspase-2 (caspase-2S) could be identified. Treatment of human U937 macrophages with the DNA strand-breaking agents etoposide or camptothecin stimulated caspase-2S expression. Since atherosclerotic plaques contain a high number of DNA strand breaks, our results provide evidence for a survival factor in macrophage-derived foam cells of human atherosclerotic plaques that might be up-regulated in response to DNA damage.

Influence of tranexamic acid in postoperative bleeding of cardiac surgery with cardiopulmonary bypass

OBJECTIVE: To analyze the influence of tranexamic acid in postoperative bleeding of cardiac surgery with cardiopulmonary bypass. METHOD: 51 patients who underwent heart surgery with cardiopulmonary bypass were randomly divided in 2 groups: Group I - control, with 12 coronary artery disease patients and 14 valve disease patients. Group II - Tranexamic acid, with 14 coronary artery disease patients and 11 valve disease patients. The Group I after venous access, received 250 ml of 0.9% normal saline solution as a placebo, Group II received 100 milligram per kilogram of body weight of tranexamic acid diluted in 250 ml of 0.9% normal saline solution. Blood samples were taken and examined at entry to Intensive care unit and after 12, 24 and 36 hours in the postoperative period. The groups were compared concerning factors which might influence the postoperative bleeding and transfusion required: age, gender, creatinine, duration of Cardiopulmonary bypass, hematocrit, platelets and fibrinogen variations, number of saphenous vein grafts performed, mammary artery used and valve replacement or repair. The postoperative bleeding was evaluated from the 1st to 4th hours and the total. Data were analyzed by appropriate statistic methods (Student T-test, X² test and Fischer's test); a p-value of less than 0.05 was the accepted level of significance. RESULTS: Concerning the postoperative bleeding and transfusion required, there was a statistically significant reduction in its average in valve disease patients in Group II. In coronary disease patients there was only a slight tendency. There was no significant statistical difference as far as the thromboembolic or renal complications were concerned. CONCLUSION: In valve disease patients, there was a reduction in bleeding and the need of transfusions of red blood cells, both of which had statistical differences. In coronary disease patients there was only a reduced tendency. The use of tranexamic acid was not related to further thromboembolic complications or renal insufficiency in the assessed groups.

Plasma levels and cardiovascular gene expression of urotensin-II in human heart failure

The peptide urotensin-II (U-II) has been described as most potent vasoconstrictor identified so far, but plasma values in humans and its role in cardiovascular pathophysiology are unknown. We investigated circulating urotensin-II and its potential role in human congestive heart failure (CHF). We enrolled control individuals ( n=13; cardiac index [CI], 3.5±0.1 l/min/m 2; pulmonary wedge pressure [PCWP], 10±1 mm Hg), patients with moderate ( n=10; CI, 2.9±0.3 l/min/m 2; PCWP, 14±2 mm Hg) and severe CHF ( n=11; CI, 1.8±0.2 l/min/m 2; PCWP, 33±2 mm Hg). Plasma levels of urotensin-II differed neither between controls, patients with moderate and severe CHF nor between different sites of measurement (pulmonary artery, left ventricle, coronary sinus, antecubital vein) within the single groups. Hemodynamic improvement by vasodilator therapy in severe CHF (CI, +78±3%; PCWP, −55±3%) did not affect circulating U-II over 24 h. Preprourotensin-II mRNA expression in right atria, left ventricles, mammary arteries and saphenous veins did not differ between controls with normal heart function and patients with end-stage CHF. In conclusion, urotensin-II plasma levels and its myocardial and vascular gene expression are unchanged in human CHF. Circulating urotensin-II does not respond to acute hemodynamic improvement. These findings suggest that urotensin-II does not play a major role in human CHF.

Vasorelaxant properties of isolated human radial arteries: comparison with internal mammary arteries

Radial arteries, used in revascularisation surgery, are prone to spasm. We have examined the ability of nitrovasodilators, calcium channel blockers, and K ATP channel openers to cause vasodilation, and to attenuate contractions due to depolarisation and receptor activation in radial and mammary arteries used in coronary artery bypass graft surgery. Two to three millimetre rings of artery obtained from patients at surgery were studied in organ baths in vitro. Constriction to KC1 and phenylephrine was examined before and again after treatment of the rings with drug or vehicle. Calcium channel blockers were the only compounds to inhibit contractions to both KC1 and phenylephrine. Sodium nitroprusside attenuated constriction to phenylephrine but not KC1 in both vessels. K ATP channel openers similarly attenuated constriction to phenylephrine in radial arteries but were much less effective in mammary arteries. These studies support the continued use of calcium blockers after revascularisation with radial artery but suggest that other classes of drug may be as effective at minimising spasm due to receptor mediated constriction.

Plasminogen activator inhibitor type 1 is increased in the arterial wall of type II diabetic subjects.

Plasma plasminogen activator inhibitor type 1 (PAI-1) increases in diabetes, and this might contribute to decreased fibrinolysis and accelerated atherosclerosis. Increased PAI-1 levels in the vessel wall could decrease local fibrinolysis and elevate thrombus formation and the unfavorable evolution of atherosclerotic plaques. High glucose increases PAI-1 synthesis in arterial wall cells in culture, and aortic wall PAI-1 levels have been found to be elevated in diabetic animals. However, arterial wall PAI-1 levels have not been investigated in diabetic subjects. Therefore, the aim of this study was to determine the effect of diabetes on PAI-1 levels in the arterial wall. Blood samples and small tissue specimens from the mammary artery were obtained from 11 diabetic and 10 nondiabetic subjects who underwent coronary artery bypass graft surgery. PAI-1 antigen localization in the arterial wall was obtained by immunohistochemistry and was read by laser scanning confocal microscopy; plasma fibrinolytic activity was measured by lysis of fibrin plates; and PAI-1 activity was assessed by a chromogenic method. PAI-1-related immunofluorescence was increased in the arterial wall of diabetic patients, whereas plasma fibrinolysis was reduced. These data provide evidence that diabetes is associated with increased PAI-1 in the arterial wall. This might be an important factor for increased cardiovascular risk and unfavorable plaque evolution in diabetes.

Resultados clínicos de la revascularización miocárdica con doble arteria mamaria frente a única: 15 años de seguimiento

Use of the left internal mammary artery to bypass the left anterior descending coronary artery reduces cardiac events and increases survival. However, there is some controversy as to the benefits of using both mammary arteries. To assess the long-term outcome of the use of both mammary arteries in comparison with the use of only one. A retrospective cohort study with a mean follow-up of 9.0 +/- 4.2 years was performed including 108 patients consecutively revascularized using both mammary arteries (II) and 108 patients randomly chosen in whom one mammary artery (I) was used for this purpose. Both groups were similar. There were no differences between the groups in operative morbidity or mortality. The survival at 10 years was similar (II: 84.61 +/- 4%; I: 85.18 +/- 3.8%), whereas recurrence of angina (II: 29.63 +/- 5.3%; I: 47.55 +/- 5.6%) (p = 0.012), the requirement for percutaneous angioplasty (II: 3.98 +/- 2%; I: 12.99 +/- 4.1%) (p = 0.009) and cardiologic events (II: 33.48 +/- 5.5%; I: 48.48 +/- 5.5%)(p = 0.022) were all lower in the group in which both mammary arteries were used. In the multivariate analysis, the use of both mammary arteries was an independent protective factor against angina recurrence (RR = 0.55), angioplasty (RR = 0.18) and cardiologic event (RR = 0.60). The use of both mammary arteries for revascularization does not increase operative morbidity. Since this procedure acts as an independent factor against angina recurrence, angioplasty and cardiologic event

Right Y-graft, a new surgical technique using mammary arteries for total myocardial revascularization

Background. We report a new technique that consists of a right Y-graft using only skeletonized internal mammary arteries (IMA) for total arterial myocardial revascularization. Methods. This technique consists of anastomosing the in situ left IMA (LIMA) and right IMA (RIMA) to the left anterior descending and obtuse marginal artery, via the transverse sinus, respectively. The distal free LIMA was anastomosed to the right coronary artery and afterwards in a Y fashion to the RIMA stem. Eleven patients with triple-vessel disease underwent coronary artery bypass grafting using this technique. Postoperatively and at follow-up all patients underwent color Doppler contrast-enhanced transthoracic echocardiography (TTE) before and after an adenosine provocation test. Results. Overall, 33 IMA-coronary anastomoses were made and 11 right Y-grafts were constructed. At 1 week after operation color Doppler contrast-enhanced TTE before and after the adenosine provocation test, respectively, showed an increase in LIMA stem diameter of 0.31 mm and in mean flow 62 mL/min. Coronary flow reserve (CFR) was 2 ± 0.3. The increase in RIMA stem diameter was 0.2 mm and in mean flow was 121.7 mL/min. Coronary flow reserve was 2.5 ± 0.4. Only 1 patient demonstrated an anomalous Doppler pattern, suggesting a partial Y-graft closure. Conclusions. Such a technique permits total myocardial revascularization using only mammary arteries and left ventricular perfusion from both IMAs simultaneously. The color Doppler contrast-enhanced TTE is a rapid, accurate, and noninvasive test allowing a good assessment of IMA patency.

Eficacia de la tomogammagrafía miocárdica en la valoración de la permeabilidad de los injertos aortocoronarios

Conventional ergometry has limitations in the evaluation of coronary artery bypass graft patency. The aim of the present study was to determine the efficacy of exercise single photon emission tomography with 99mTc-compounds for the diagnosis of coronary artery bypass grafts disease. The state of sixty-seven coronary artery bypass grafts (31 with mammary artery, 36 with safein vein; 35 to left descending anterior artery, 15 to circumflex and 17 to right coronary artery) were analyzed retrospectively in 38 patients (mean age 63+/-8.7; 35 men). The time that elapsed between the coronary surgery and the exercise tomography was 9,7 years. In 16 cases, exercise tomography was performed with 99mTc-MIBI and in the 22 remaining with 99mTc-tetrofosmin. In 6 cases, dipiridamol was administred simultaneously during an insufficient exercise test. Sensitivity (73.1%), specificity (93%), positive predictive value (86.3%), negative predictive value (84.4%), global value (85%), positive likelihood ratio (10.4) and negative likelihood ratio (0.29) of exercise tomography were significantly (p<0.01) better than those obtained with the exercise test alone (53.8%, 43.6%, 38.9%, 58. 6%, 47.7%, 0.95 and 1.06, respectively). Exercise tomography with 99mTc-compounds is a highly effective for the detection of coronary artery bypass grafts disease.