Internal Mammary Artery In Patients Research Articles

Duplex Imaging Assessment of the Internal Mammary Arteries in Women after Unilateral Mastectomy and Radiotherapy for Breast Cancer

The effects of incidental radiation exposure on internal mammary arteries remain unclear. The present study was designed to test the hypothesis by comparing diameter and blood flow of the irradiated and nonirradiated internal mammary arteries, using Duplex ultrasound imaging. The study was designed as a single-center, transversal, comparative study. The main outcomes were diameter and volumetric blood flow of the internal mammary arteries. The Wilcoxon rank-sum test was used to assess the differences between the irradiated and nonirradiated internal mammary arteries with regard to the diameter and volumetric blood flow. The diameter (median [interquartile range]) of the irradiated internal mammary arteries (0.170mm [0.160, 0.180]) was smaller than that of the contralateral nonirradiated ones (0.180mm [0.170, 0.200], P<0.0001) and that of the internal mammary arteries in the control group (0.180mm [0.170, 0.190], P<0.0001). Similarly, blood flow (median [interquartile range]) of the irradiated internal mammary arteries (52.4ml/min [37.78, 65.57]) was smaller than that of the contralateral nonirradiated ones (62.7ml/min [46.87, 84.17], P<0.0001), as well as of the left (56.7ml/min [46.88, 72.58], P=0.02) and the right internal mammary arteries in the control group (61.0ml/min [47.47, 74.52], P=0 0.0009). The data indicate that the irradiated internal mammary arteries in patients with a history of total mastectomy followed by radiotherapy for breast cancer had significantly smaller diameter and blood flow compared to the nonirradiated internal mammary arteries.

Off-Pump Coronary Artery Bypass Graft Surgery with Bilateral Internal Mammary Arteries in Left Main Coronary Artery Disease. Is There Any Benefit in 10-Year Mortality?

Background: The randomized controlled trials comparing coronary artery bypass graft (CABG) surgery versus percutaneous coronary intervention (PCI) included all types of surgical techniques (on-pump and off-pump) and different conduits (arterial and venous). Is it reasonable to assume that all surgical techniques are equal in terms of late mortality? Objectives: The aim of this study was to evaluate whether off-pump CABG surgery using both mammary arteries provides additional benefit over conventional revascularization using single mammary artery in terms of long-term survival for left main coronary artery (LMCA) disease. Methods: We conducted a retrospective, observational and comparative study (n=723) adjusted for risk. A stratified analysis was performed according to the use of single internal thoracic artery (SITA, n=144) or bilateral internal thoracic arteries (BITA, n=579) analyzing survival at 10 years after the intervention. Results: Survival at 10 years was significantly higher in BITA group (79.0%±3.4% vs 67.0%±4.9%, log-rank test, p &lt;0.01). This advantage was also observed in the risk-adjusted analysis (93.0%±4.6 vs 69.0%±5.7 respectively, p=0.03). The use of BITA was an independent predictor of 10-year survival (HR 0.57, 95% CI 0.37-0.87, p=0.01). Conclusion: The use of bilateral internal mammary arteries in patients with left main coronary artery disease undergoing off-pump coronary artery bypass grafting was associated with higher survival at 10 years.

Perivascular adipose tissue from the internal mammary artery in patients with severe coronary artery atherosclerosis.

he internal mammary artery (IMA) is routinely used as an arterial graft for coronary artery bypass grafting with an excellent long‑term patency rate, but its protective mechanism is unclear. We evaluated the differences between the expression of several gene in perivascular adipose tissue from the IMA (PVAT‑IMA) as compared with other fat depots in patients with severe coronary artery disease. A total of 53 patients (13 women) with severe coronary artery disease and preserved left ventricular ejection fraction were scheduled for coronary artery bypass grafting. Clinical assessment, anthropometric parameters, and quantification of fat depots were performed in all patients. The relative expression of the following genes were obtained in PVAT‑IMA, as well as epicardial, pericardial, and subcutaneous (SF) fat samples: angiotensinogen (AGT), angiotensin I converting enzyme 1 and 2 (ACE1and ACE2), glucagon‑like peptide receptors type 1 and 2 (GLP1R and GLP2R), phospholipid transfer protein (PLTP), adiponectin (ADIPOQ), omentin‑1 (ITLN1), and uncoupling protein 1 (UCP1). The expression of UCP1 (median [interquartile range [IQR], 2.5 [0.91-16.6]; P <0.01) and AGT(2.22 [0.65-6.2]; P <0.01) was higher in PVAT‑IMA compared with the SF depot. ADIPOQ expression was lower in pericardial and epicardial fat depots (median [IQR], 0.44 [0.23-2.3]; P <0.01). The expression of ITLN1 was increased in PVAT‑IMA as compared with epicardial and pericardial fat (P <0.001). PVAT‑IMA revealed differences in the expression of selected genes in relation to SF. We found a higher expression of ITLN1 in PVAT‑IMA compared with other adipose tissue depots, which could be associated with protective mechanisms against atherosclerosis in IMA. However, this remains a subject for further studies.

Histopathology and Morphometric Analysis of the Internal Mammary Artery to Study the Incidence of Atherosclerosis and Its Associated Risk Factors

Background: The left internal mammary artery (IMA) is widely used as a conduit for coronary revascularization. The incidence of atherosclerosis is known to be lower in the IMA than in the coronary artery. The aim of this study was to evaluate the reliability of the use of the distal section of the IMA as an anastomotic site for bypass grafting and morphometric studies of IMA in patients with proven coronary artery disease and their associated risk factors. Methods: Patients who underwent Coronary Artery Bypass Graft (CABG) from June 2010 to November 2012 were chosen in this retrospective study and the discarded distal segments of the internal mammary artery were analyzed. The potential risk factors for atherosclerosis considered were age, sex, diabetes mellitus, history of cigarette smoking, hypertension and hypercholesterolemia. The samples were analyzed for the degree of intimal thickening and atherosclerosis by calculating the percentage of Luminal Narrowing, Intimal Thickness Index (ITI) and Intima-to-Media Ratio (IMR). Results: There were seven cases of intimal hyperplasia and two cases of focal medial and intimal hyperplasia with fatty streak and no cases of atherosclerosis and medial calcification. ITI was higher in males when compared to females. There was a strong relationship between IMR and smokers when compared to nonsmokers. Conclusion: In our study, when ITI was used as the dependent variable, diabetes was the most important factor. When IMR was used, the strongest predictor was hypercholesterolemia. There was a strong relationship between IMR and smokers when compared to nonsmokers.

A side-hole catheter for catheterization of a difficult internal mammary artery.

Background The internal mammary artery (IMA) can be a source of hemoptysis in patients with chronic lung disease. Intervention via the IMA can be a challenge due to anatomic variations and lead to excessive contrast use and radiation exposure. Purpose To evaluate safety and efficiency of a new side-hole catheter for the catheterization of the IMA in patients with hemoptysis. Material and Methods From January 2011 to August 2014, a total of 96 transarterial embolization procedures required exact evaluation of the IMA due to chronic lung disease involving the anterior thorax. In 17 cases (18%) of these 96 procedures, the conventional selective IMA angiography failed and instead a novel side-hole catheter as a modification of a cobra-type curved catheter was used. The side hole allowed passage of a micro-wire and catheter. Results Failed catheterizations were due to severe vascular tortuosity, acutely angulated subclavian artery, or abnormal takeoff of the IMA. The Cobra shaped catheter with the microcatheter through the side-hole catheter yielded a technical success rate of 100%. Longer time was required to catheterize the IMA with the Cobra shaped catheter than with the side-hole catheter (17 vs. 2 min, P < 0.05). There were no procedure-related complications. Conclusion Side-hole catheter technique is useful in patients whose internal mammary artery is difficult to access. Further design revisions are needed to improve the ease and speed of IMA catheterization and angiography.

Efficacy of multiple arterial coronary bypass grafting in patients with diabetes mellitus.

Use of the left internal mammary artery in patients with diabetes mellitus and multivessel coronary artery disease is known to improve survival after coronary artery bypass grafting (CABG); however, the survival benefit of multiple arterial grafts (MAGs) in diabetic patients is debated. We investigated the efficacy of CABG performed with MAGs in diabetic patients. The overall patient group comprised 2618 consecutive patients who underwent isolated CABG at our hospital between 1990 and 2014. Perioperative characteristics, in-hospital outcomes and long-term outcomes were compared between diabetic (n = 1110) and non-diabetic patients (n = 1508). The long-term outcomes of diabetic and non-diabetic patients were analysed between those who received a single arterial graft (SAG) and those who received MAGs. Both full unmatched patient population and propensity-matched patient population analyses (diabetic cohort = 431 pairs, non-diabetic cohort = 577 pairs) were performed. Preoperative comorbidities were much more common in the diabetic patients than in the non-diabetic patients; however, comorbidities were not associated with in-hospital outcomes (diabetes versus non-diabetes group, in-hospital mortality: 2.2 vs 1.5%; deep sternal wound infection: 2.2 vs 1.8%, P > 0.05). Although survival and freedom from major cardiac and cerebrovascular events (MACCEs) at 15 years were lower in the diabetes group than in the non-diabetes group (survival: 48.6 vs 55.0%, P = 0.019; MACCE-free survival: 40.8 vs 46.1%, P = 0.02), cardiac death-free survival at 15 years was similar (81.7 vs 83.9%, P = 0.24). Overall, 12-year survival was higher in both diabetic and non-diabetic patients treated with MAGs than in those treated with an SAG (64.9 vs 56.8%, P = 0.006, and 71.9 vs 60.5%, P < 0.001). Propensity-matched patient cohort analysis revealed improved 12-year survival with MAGs versus SAG in both the diabetes group (64.9 vs 58.8%, P = 0.041) and non-diabetes group (71.4 vs 63.8%, P = 0.014). Similarly, MACCE-free survival was improved in both groups. A long-term survival advantage, with no increase in perioperative morbidity, is conferred with the use of multiple arterial bypass grafts not only in non-diabetic patients but also in diabetic patients.

Vertebral and internal mammary artery steal syndrome in patients with hemodialysis access.

Increased flow in the subclavian artery feeding a vascular access for hemodialysis can induce steal phenomena in the vertebral (VA) and internal mammary artery (IMA). The aim of this study was to describe the hemodynamic effects of access flow on the VA and IMA in patients with native fistulas and grafts. Peak systolic (PSV) and end diastolic (EDV) velocity measurements of the VA, IMA and carotid arteries, as well as flow volume measurements of the subclavian artery, were performed. Flow measurements at the side of the vascular access were compared with the contralateral side. Fifty-five patients were consecutively included, most with a radio-cephalic fistula on the left arm with a mean shunt volume of 1156 ml/min. Pathologic flow patterns were observed in the ipsilateral VA in four patients (7.3 %); contralateral VA flow was normal in all patients. Peak systolic velocity of the VA was significantly decreased at the side of the shunt arm with a PSV of 42.6 ± 11.8 cm/s compared to 48.4 ± 15.6 cm/s contralateral (p < 0.05). The IMA flow pattern were normal in all patients. The PSV of the IMA was significantly decreased (p < 0.01) at the side of the shunt arm (87.5 ± 29.1 cm/s) compared to the non-shunt arm (95.9 ± 27.4 cm/s). We describe significant hemodynamic effects of fistulas to the vertebral and internal mammary arteries. Doppler spectral analysis of the vertebral and internal mammary arteries should be integrated in ultrasound, especially in patients with cerebrovascular or cardiac symptoms.

Vertebral and internal mammary artery steal phenomena in patients with hemodialysis access

Aim: Increased flow in the subclavian artery feeding a vascular access for hemodialysis can induce steal phenomena of the vertebral (VA) and internal mammary artery (IMA). Systematic investigations of Doppler flow changes of the VA and IMA are lacking. Aim of the study is to describe the hemodynamic effects of access flow on VA and IMA in patients with native fistulas and grafts.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Coronary subclavian steal syndrome

Internal mammary artery (IMA) grafts have been shown to be superior to saphenous vein grafts in terms of rare atherosclerotic involvement, biochemical and physical qualities, and long-term patency rates. The IMA originates from the subclavian artery, just distal to the vertebral artery, and an occlusion or a hemodynamically significant stenosis proximal to the IMA ostium would cause a pressure drop distally and a reversal of flow from the coronary arteries to the IMA in patients with this graft. This condition is referred to as "coronary subclavian steal syndrome" (CSSS). In most cases, the cause of this syndrome is atherosclerotic disease; however, other causes of subclavian artery stenosis (SAS) have the potential to lead to CSSS. Patients with CSSS present with the symptoms of myocardial ischemia due to coronary steal, vertebrobasilar insufficiency, or limb ischemia. Discrepancy in the blood pressure (BP) measurements in two arms should warn the clinician of SAS. A diminished pulse or the bruit of jet flow on the lesion side can be noticed. Doppler ultrasonography, computed tomography angiography, and magnetic resonance angiography are safe and accurate noninvasive modes of diagnosis. Treatment can be surgical or percutaneous.

Hemodynamic Effects of Left Upper Extremity Arteriovenous Fistula on Ipsilateral Internal Mammary Coronary Artery Bypass Graft

Arteriovenous fistula (AVF) in patients undergoing hemodialysis (HD) may cause coronary left internal mammary artery (IMA) steal. This phenomenon was demonstrated by few prospective studies with limited number of patients and case reports. We aimed to demonstrate with a relatively larger patient population that the AVF may cause ipsilateral IMA steal. We included 22 prospective patients undergoing HD who had left IMA to left anterior descending artery graft and left upper limb AVF. Right IMA was taken as control. Flows were assessed by using color Doppler ultrasonography. The mean age was 57.8 ± 9 years. Statistically nonsignificant increases in AVF flow and decreases in left IMA flow were observed during HD compared with pre-HD. Moreover, fistula localization did not affect median left IMA flows (for peak systolic velocity [PSV] 43.7 versus 70 cm/s, respectively; p = 0.7, and for end diastolic velocity [EDV] 3.4 versus 6.5 cm/s, respectively; p = 0.7). We have not detected significant difference in left IMA flows during HD (median values of PSV 58.4 versus 68.4 cm/s, respectively; p = 0.1, and EDV 6.4 versus 4.4 cm/s, respectively; p = 0.08). Only three patients experienced dialysis-induced reduction of ipsilateral IMA flow that was accompanied by evidence of hypokinesia of the anterior left ventricular wall without clinical angina. Hemodynamically affected left IMA flow by ipsilateral upper extremity AVF may cause steal phenomenon. Hemodynamic differences between left and right IMAs in patients undergoing HD via left wrist and brachial fistulae are limited.

The anatomic evaluation of internal mammarian artery by using multidetector CT angiography

To determine the normal anatomic features and variations of the internal mammary arteries (IMAs) and to describe the relationship between the diameter and distance to the sternal edge of the IMAs, gender, and location (right-left) of the IMAs in patients who underwent multidetector computed tomography (MDCT) angiography of the thorax for various reasons. A total of 164 patients who underwent MDCT angiography of the thoracic vascular structures for various reasons were analyzed retrospectively. The right and left IMAs were analyzed individually, and normal anatomic features and variations were recorded. The relationships between gender, side and diameter of the IMAs, and distance to the sternal edge of the IMAs were evaluated. There were 328 (164 right, 164 left) IMAs in 164 patients (110 males, 54 females; mean age, 43.96 years). A total number of five arteries (1.5%) had anatomic variation. Whereas 325 IMAs had an origin separate from the subclavian artery, three LIMA of the 328 arteries (0.91%) had a common origin with the thyrocervical trunk or costocervical trunk. Two (0.6%) IMAs (one LIMA and one RIMA) in the same patient were duplicated at the level of the first and second costal cartilage. There were no statistically significant correlations between age and diameter or between gender and diameter of the RIMA and LIMA at the origin and level of tracheal bifurcation (P > 0.05). Mean distance between the lateral margin of the sternum and midpoint of LIMA and RIMA were 12.42 mm and 13.00 mm, respectively. The normal anatomic features and variations of the IMAs have an important role in cardiovascular bypass surgery, breast reconstruction, and percutaneous transthoracic procedures. MDCT angiography allows a precise and detailed evaluation of IMAs.

Left Internal Mammary Artery Atherosclerosis: Twenty-Three Years After Repair of Aortic Coarctation

Atherosclerosis of the internal mammary artery is a rare disease. We describe a case in which a 41-year-old man underwent coronary artery bypass surgery 23 years after repair of aortic coarctation. The diseased mammary artery was used to graft the left anterior descending coronary artery after intraoperative confirmation of good patency. Early graft occlusion occurred a few days after the operation. This case demonstrates that atherosclerosis affects mammary arteries after long-term repair of aortic coarctation. Such conduits should not be used, even in the presence of good blood flow.

Comparison of fatty acid profiles of aorta and internal mammary arteries in patients with coronary artery disease

Background Atherosclerosis represents the principal cause of death in the many societies. Since few data have been published about the composition of fatty acids in atherosclerotic arteries such as the aorta comparing to the non affected internal mammary artery which is used for aortocoronary bypass grafting, we compared the fatty acid profiles of atherosclerotic aorta and internal mammary arteries in human individuals. Methods Twenty-one angiographically documented coronary artery disease (CAD) patients who were admitted to the open heart surgery division enrolled in this study. They were operated electively for coronary artery bypass grafting surgery (CABG). Small segments of ascending aorta and internal mammary arteries were sampled during open heart surgery. The samples were subjected to lipid extraction and fatty acid analysis by high performance liquid chromatography. Results The results showed that different fatty acid profiles were seen in the aorta and internal mammary arteries. The atherosclerotic aorta contained lower amounts of unsaturated fatty acids (including trans isomer of oleic acid) and higher proportions of saturated fats comparing to the internal mammary. In the aorta also, the amounts of ω6 series of fatty acids were more and levels of ω3 fats were less than the internal mammary. Conclusion This study suggests that modification of fatty acids may play a role during atherogenesis.

What is the optimal vasodilator for preventing spasm in the left internal mammary artery during coronary arterial bypass grafting?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was which (if any) vasodilator prevents spasm of the internal mammary artery in patients undergoing coronary artery bypass grafting. Two hundred papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses were tabulated. We conclude that mammary arteries often have low flow initially, but invariably will double their flow after 15-20 min even with no treatment. The strongest evidence for safe prevention of spasm is for papaverine given topically and periarterially, however many studies have also shown no benefit and thus no treatment at all is an entirely acceptable strategy.

Skeletonized versus pedicled internal mammary artery: impact of surgical technique on post CABG surgery pain

Recent evidence suggests that coronary artery bypass graft (CABG) surgery often results in chronic chest wall pain, termed: 'post CABG pain syndrome' (PCP). Direct injury to intercostal nerves during the surgical procedure was presumed to underlie this syndrome. The aim of this study was to investigate the effect of two harvesting techniques of the internal mammary artery (IMA)-skeletonization (S-LIMA) and pedicle (P-LIMA) on the occurrence and incidence of PCP. A mailed questionnaire enquiring about the presence and characteristics of PCP was sent to all 482 patients who had undergone CABG in our institution in the years 1999-2000. A randomly chosen subgroup of IMA patients reporting PCP were summoned for evaluations of pain localization and intensity, thermal and tactile sensitivity, and disability assessment using recognized tests and indices. Of the 380 responders (S-LIMA: 221, P-LIMA: 125, veins only V-34) 169 (44%) reported having PCP. Its prevalence was similar between the two IMA groups (S-LIMA: 45%, P-LIMA: 50%) but significantly lower in the V group (18%, P=0.003). Physical assessment in the subgroup of 43 IMA patients (S-LIMA: 22, P-LIMA: 21) performed 40.2+/-8.7 months after surgery confirmed equal occurrence of mostly left and midline chest wall neuropathic pain in both IMA groups. No significant differences were found between the two groups in respect to indices of pain intensity, thermal and tactile sensitivity and disability. PCP is a prevalent finding in post CABG patients. The skeletonization technique of IMA harvesting although causing significantly less inner chest wall trauma does not appear to reduce the occurrence of PCP. This finding may imply that ischemic injury rather than direct mechanical injury to the intercostal nerves is the putative mechanism underlying PCP.

Postoperative Changes in Duplex Ultrasound Velocity Characteristics in the Nonmobilized Right Internal Mammary Artery in Patients with Left Internal Mammary Artery Bypass Grafting

The internal mammary artery (IMA) is the conduit of choice in coronary revascularization because of its long-term patency. We analyzed the effect of left internal mammary artery (LIMA) harvesting on sternal perfusion. Diameters and velocity parameters of the nonmobilized right internal mammary artery (RIMA) were noninvasively analyzed with duplex ultrasound in 41 patients with LIMA myocardial revascularization pre- (2.6 +/- 5 days) and postoperatively (4.9 +/- 3.9 months). Data of 41 patients were analyzed; 38 patients underwent all examinations with adequate supraclavicular signals. The proximal RIMA diameter and all velocity parameters increased significantly at follow-up (3.1 +/- 0.6 vs. 3.2 +/- 0.5 mm, p = 0.03; diastolic peak velocity [DPV] 15 +/- 7 vs. 27 +/- 9 cm/sec, p < 0.0001; systolic peak velocity [SPV] 90 +/- 24 vs. 105 +/- 29 cm/sec, p < 0.02). This was more pronounced for the diastolic parameters and for all parameters in the proximal part of the RIMA than in the distal part (DPV 11.9 +/- 10.1 vs. 9.5 +/- 10.2 cm/sec, p = NS; SPV 14.9 +/- 33.9 vs. 7.4 +/- 26.0 cm/sec, p = NS). With longer time intervals of follow-up the increase in all diastolic velocity parameters became less pronounced. As demonstrated in the RIMA velocity parameters, patients with skeletonized LIMA grafts (n = 4) had significantly more flow, suggesting hyperemic flow, than patients with pedicled LIMA grafts (n = 34). Only in diastolic velocity integral (DVI) and systolic/diastolic velocity ratio (SDVRA) were there significant differences between diabetics (n = 9) and nondiabetics (n = 29) and only in DVI between female, (n = 8) and male (n = 30) patients. This study indicates that duplex ultrasound is a useful tool for noninvasive RIMA follow-up in LIMA myocardial revascularization.

Coronary steal from a left internal mammary artery coronary bypass graft by a left upper extremity arteriovenous hemodialysis fistula

In patients with end-stage renal disease undergoing hemodialysis, the upper extremity arteriovenous (AV) fistula is the dialysis access recommended by the DOQI guidelines for patients with appropriate vasculature. Upper extremity AV fistulae have long periods of usefulness, high flow rates, and low associated complication rates. Placement of AV access may result in increased cardiac output and increased cardiac oxygen demand in these patients. In general, cardiovascular complications from AV access have been limited. We report a novel cardiovascular complication of AV access in an end-stage renal disease patient with a coronary artery bypass graft employing the left internal mammary artery who experienced angina while undergoing hemodialysis. The angina was mediated at least in part by cardiac catheterization laboratory-documented steal of blood flow from the internal mammary artery graft. This phenomenon suggests the need to consider the impact of upper extremity access placement on blood flow to the left internal mammary artery in patients who previously have undergone placement of a coronary artery bypass graft. © 2002 by the National Kidney Foundation, Inc.

Acute pleuropulmonary complications detected by computed tomography following myocardial revascularization.

Pleuropulmonary changes are common following coronary artery bypass grafting surgery performed with a saphenous vein graft, with or without an internal mammary artery. The presence of atelectasis or pleural effusions reflects the thoracic trauma. To define the postoperative incidence of changes in the lung and in the pleural space and to evaluate the influence of the trauma. Thirty patients underwent elective coronary artery bypass grafting surgery (8 saphenous vein grafts and 22 saphenous vein grafts and internal mammary artery grafts with pleurotomy). Chest tubes in the left pleural space were used in all internal mammary artery patients. On the second (day 2) and seventh (day 7) postoperative day, patients underwent a computed tomography, and pleural effusions were rated as follows: grade 0 = no fluid to grade 4 = fluid in more than 75% of the hemithorax. Atelectasis was rated as follows: laminar = 1, segmental = 3, and lobar = 10 points. All patients had pleural effusion or atelectasis. Between day 2 and day 7, the number of patients with effusions or atelectasis on the right side decreased (P < 0.05). The incidence of effusions on day 2 in the saphenous vein graft group (87.5%) was higher (P < 0.05) than in the internal mammary artery group (52.3%). The incidence of atelectasis in the lower right lobe decreased (P < 0.05) from 86.7% (day 2) to 26.7% (day 7). The degree of atelectasis in both sides did not differ on day 2 (P = 0.42) but did on day 7 (P < 0.0001). There was a decrease in the atelectasis from day 2 to day 7 on the right side (P < 0.001), but not on the left (P = 0.21). On day 2 there was a relationship between atelectasis and effusion on the right (P = 0.04), but not on the left (P = 0.113). The present series demonstrates that there is a high incidence of both minimal pleural effusion and atelectasis after coronary artery bypass grafting surgery, which drops on the right side from day 2 to day 7 post surgery. Factors that contribute to the persistence of changes on the left side include the thoracic trauma and the presence of chest tubes and pericardial effusion.

Transthoracic Doppler echocardiographic comparison of left internal mammary grafts to left anterior descending coronary artery with ungrafted right internal mammary arteries in patients with and without myocardial ischemia by dobutamine stress echocardiography

To characterize Doppler flow patterns of the grafted left internal mammary artery (LIMA) in patients with and without dobutamine stress induced wall motion abnormalities in the graft distribution, we studied 29 patients who underwent coronary artery bypass surgery using LIMA grafts to the left anterior descending coronary artery (LAD). The ungrafted right internal mammary artery (RIMA) was used as a control. RIMA Doppler flow pattern was predominantly systolic in all patients. In patients without ischemia in the LAD distribution, LIMA flow was predominantly diastolic. In patients with ischemia, LIMA flow was predominantly systolic. In the grafted LIMA, a ratio of diastolic to systolic time-velocity integral of >1.5 best showed absence of ischemia in the graft distribution. In summary, characterization of the Doppler flow pattern in the internal mammary arteries is feasible. In the grafted LIMA, ratios of diastolic to systolic flow are less in patients with an ischemic response in the subtended vascular bed than in those without ischemia.