Use Of Internal Mammary Artery Research Articles

Phrenic Nerve Injury After Coronary Artery Grafting: Is It Always Benign?

Background. The purpose of this study was to evaluate the effect of phrenic nerve injury (PNI) occurring during coronary artery bypass grafting in patients with major chronic obstructive pulmonary disease (COPD). Methods. Over a 42-month period, 1,303 patients underwent primary coronary artery bypass grafting. Sixty-seven (5.14%) had major COPD, and 29 (43.3%) of these 67 sustained PNI (group I). These patients were matched for age and ejection fraction with 29 CABG patients with COPD but without PNI (group II), 29 patients without COPD but with PNI (group III), and 29 patients with neither COPD nor PNI (group IV). The groups were compared on the basis of preoperative and operative factors and immediate and midterm morbidity and mortality. Results. There were no significant differences between the groups with respect to hypertension, diabetes, ejection fraction, number of grafts, internal mammary artery use, cardiopulmonary bypass time, and ischemic time. Postoperatively, group I had a longer total hospitalization (group I, 11.7 days; group II, 7.8 days; group III, 7.8 days; and group IV, 6 days; p = 0.0001) and stay in the intensive care unit (I, 3.6 days; II, 2.2 days; III, 2.1 days; and IV, 1.2 days; p = 0.0023). More patients in group I required reintubation (I, 37.9%; II, 3.4%; III, 6.9%; and IV, 0%; p < 0.0001). Mean follow-up was 32.8 months (range, 7 to 48 months). Group I had more hospital readmissions (I, 78; II, 50; III, 61; and IV, 28; p < 0.007) and lower cumulative survival (I, 60.6%; II, 93%; III, 96.8%; and IV, 100%; p < 0.0015) compared with the other groups. Conclusions. In patients with COPD, PNI during coronary artery bypass grafting has a major negative impact on immediate and midterm results.

Retrosternal fat pad for prevention of suppurative sternitis

An increased incidence of postoperative sternal infection has been reported after the use of bilateral internal mammary arteries for coronary artery grafting. In this series, a pedicled pericardial fat pad was mobilized to lie in the retrosternal space before the sternum was approximated. This technique was used in 101 consecutive patients who underwent coronary artery grafting using bilateral internal mammary arteries. Twenty-four percent of the patients were diabetic. No suppurative sternitis developed in any of these patients.

Gastrointestinal complications following cardiac surgery. An analysis of 1477 cardiac surgery patients.

To determine preoperative and perioperative risk factors for gastrointestinal (GI) complications following cardiac surgery. A database including records of patients who underwent cardiac surgery was reviewed, with univariate analysis of several variables thought to be relevant to GI complications. Using a risk-adjusted model, preoperative stratification was used to fit a logistic regression model including operative features. All patients undergoing cardiac surgery from January 1, 1991, to December 31, 1994, at a university-affiliated teaching hospital. Incidence of GI complications, postoperative mortality, length of hospital stay, and relative risk of GI complications based on multivariate analyses. Gastrointestinal complications occurred in 2.1% of patients and had an associated mortality of 19.4%; this was higher than the mortality in patients without GI complications (4.1%; P < .001). Length of hospital stay was significantly longer in patients with GI complications (43 vs 13.4 days; P < .001). In patients who underwent coronary artery bypass grafting only, cardiopulmonary bypass time was significantly longer in patients with GI complications (166 vs 138 minutes; P = .004). In patients who underwent valve replacement, bypass time was not associated with GI complications. Use of a left internal mammary artery graft was associated with a lower incidence of GI complications. Patients who have GI complications after cardiac surgery have a higher mortality and a longer hospital stay. The use of a left internal mammary artery seems to have a protective effect against GI complications. Based on these observations, patients may be stratified into low-, medium-, and high-risk groups.

Early Results with Bilateral and Single Internal Mammary Artery Grafts. Are They Different?

Between June 1991 and June 1996, 391 patients underwent isolated myocardial revascularization using bilateral internal mammary artery. Three hundred and sixty-five of these patients could be matched retrospectively on the basis of preoperative characteristics with 365 patients operated on during same period who had left internal mammary artery as a single or sequential graft with additional vein grafts. The cardiopulmonary bypass times and aortic cross-clamp times were similar in both groups. There were no statistically significant differences in the two groups in terms of operative mortality (0.55% versus 0.82%), perioperative myocardial infarction (2.46% versus 2.19%), low cardiac output (1.64% versus 1.09%), reexplorations (1.10% versus 1.92%), wound complications (1.10% versus 2.46%), length of stay in the intensive care unit, and total hospital stay. The incidence of respiratory, central nervous system, and renal complications showed no difference between the two groups. Logistic regression analysis showed that the number of internal mammary artery grafts was not a predictor for perioperative complications. If better long-term event-free survival is associated with the use of bilateral internal mammary artery, it should be used wherever possible.

Retrograde Internal Mammary Artery as Coronary Bypass: A Prospective Study with Postoperative Angiographic Evaluation

Although the internal mammary artery (IMA) as a coronary graft offers better long-term patency than the saphenous vein, a factor limiting its use has been the length of the artery's pedicle. In an attempt to overcome this limitation, we evaluated the use of retrograde right IMA in a prospective study. In ten patients scheduled for routine coronary artery bypass surgery, bilateral IMA grafting was used, the left IMA in routine fashion, but the right IMA dissected from the level of the first rib, cut there and placed as an inverted graft. Three months postoperatively the patients were clinically evaluated with stress exercise test (n = 10) and coronary angiography (n = 9). No patient had recurrence of angina. Angiography revealed patency of the retrograde right IMA graft in six of nine patients. On the basis of these data we do not recommend routine use of retrograde IMA.

Intraoperative Phrenic Nerve Monitoring in Cardiac Surgery

Left hemidiaphragmatic paralysis due to phrenic nerve lesion is a frequent complication of hypothermic cardiopulmonary bypass. Although this is believed to be caused by cold injury to the phrenic nerve, its exact cause is still not clear. To assess feasibility, safety, and usefulness of intraoperative phrenic nerve function monitoring. Elective cardiac surgery in a university hospital. Consenting patients scheduled for myocardial revascularization surgery with the use of the left internal mammary artery. Intraoperative monitoring of compound diaphragmatic action potentials (CDAPs) through transcutaneous stimulation of phrenic nerves. Patients were divided in two groups. Group 1 received intracoronary cold St. Thomas's solution as the only cardioplegic method. Group 2 received topical cardiac cooling with ice-cold solutions in addition to intracoronary cardioplegia. In all group 1 patients, function of phrenic nerves was maintained throughout the surgical procedure. Group 2: in two patients, bilateral, and in one patient, left phrenic nerve conduction was abolished after submersion of the heart in ice-cold solution. In two of them, the action potential of the left hemidiaphragm was absent by the end of surgery. In one, nerve conduction recovered with rewarming of the patient. Intraoperative monitoring of CDAP was safe and easily obtained in the intraoperative setting. It allowed us to observe changes in phrenic nerve conduction occurring during surgery and as a result of cold cardioplegia. Cryogenic lesion of phrenic nerve might explain our findings. However, nerve ischemia cannot be ruled out and it may worsen axonal damage or delay its recovery. This monitoring method allowed us to predict postoperative diaphragmatic dysfunction. Also, surgeons can be warned of the damaging effects of excessive cooling of the pericardium and surrounding structures; thus, preventive measures can be taken.

THE LIMA SUCCESS STORY — WHITHER OTHER ARTERIAL GRAFTS — ARE VEIN GRAFTS OBSOLETE ?

SUMMARY The long‐term benefit of myocardial revascularisation depends largely upon the continued patency of bypass grafts, but the long‐term patency of vein grafts is poor. To improve the results of myocardial revascularisation, either measures to increase the patency of saphenous vein grafts or alternative conduits are required. Use of the left internal mammary artery as a graft is known to increase survival, and this has prompted wider use of other arterial grafts in the expectation that they will further enhance the long‐term results of coronary artery bypass. This policy is based upon sound theory, but convincing evidence that it improves survival is lacking. Meanwhile, advances in the understanding of the pathology of vein graft occlusion have given rise to new methods of increasing vein graft patency. While these techniques are, as yet, only experimental, if translated into clinical practice, the places of arterial and venous grafts may require further assessment.

Factors influencing haemostasis and blood transfusion in cardiac surgery.

To find out the risk factors influencing perioperative bleeding and use of blood products in cardiac surgery so that appropriate interventions can be selected for blood conservation, risk factors were analysed in 343 cardiac surgical patients, retrospectively, by multiple regression technique. The results showed that the factors related to postoperative bleeding were male gender, Higgins score, cardiopulmonary bypass (CPB) time, operation procedures, intraoperative blood loss and use of internal mammary artery (IMA) graft. Factors related to perioperative homologous blood transfusions were emergency surgery, preoperative haemoglobin level, Higgins score, intraoperative blood loss, operation time and operation procedures. The geometric mean of postoperative bleeding in the entire series was 1085 ml and the mean packed red cell, plasma and platelet transfusions were 3.29 +/- 0.4, 1.96 +/- 0.39 and 0.21 +/- 0.05 units respectively. The incidence of homologous blood transfusion during the hospital stay was 58.9% for the entire series and 54.5% in the nonrevision patients. Emergency patients received significantly more blood transfusion (p = 0.0001). Perioperative blood loss and transfusions are still problems in cardiac surgery and certain patient groups in this study were identified as high risk; available blood conservation techniques, therefore, are recommended in these patients.

Valve surgery combined with coronary artery operation: is the use of internal mammary artery a predictor for early complications?

The internal mammary artery (IMA) provides better early and long-term patency than venous grafts do. Although IMA is the conduit of choice in isolated coronary artery bypass grafting (CABG), its use in combined procedures is not routine in some cardiovascular units. During a 16-month period, 188 patients underwent valve surgery combined with CABG. Internal mammary grafts were used in 68/188 (36%) patients (group 1) and vein grafts without arterial grafts (group 2) in 120/188 (64%). Left IMA was implanted in 67/68 (99%) and right IMA in 1/68 1%) cases. Surgeon A used IMA in 28/44 (64%), surgeon B in 20/32 (63%), surgeon C in 18/44 (41%), surgeon D in 1/4 (25%) and surgeon E in 1/63 (2%) patients. The final decision to use IMA in a combined procedure was left up to the surgeon. Statistically, the preoperative- and perioperative data were identical in the two groups, although the frequency of IMA grafting in patients with double valve replacement and reoperation was lower (1/68 vs 11/120, ns, and 3/68 vs 9/120, ns). Ten of 188 (5.3%) patients died within 30 days after operation. Longer cross-clamp time (P = 0.008) and mitral valve replacement (P = 0.05) were independent risk factors for early death. The use of IMA did not increase the risk of early mortality. The postoperative variables were similar in the IMA and vein groups, in particular data suggesting perioperative myocardial infarction (CK-MB, catecholamine support). Postoperative mechanical ventilation was longer in the IMA group, although not significantly (P = 0.06). Early mortality and morbidity were identical in the two groups in combined procedures. We did not find any hints for an increased risk of using IMA in this type of surgery. Internal mammary artery implantation is safe in selected patients undergoing combined valve and CABG surgery. Beside the better long-term patency of IMA, its use may have several technical advantages.

Protection of the right internal mammary artery in the retorsternal position with stented grafts

One of the limiting factors for the use of the right internal mammary artery as a pedicle graft to the anterolateral vessels of the left coronary system is the necessary midline crossover and the close proximity to the sternum. In this setting, the right internal mammary artery pedicle is at increased risk of injury during sternal reentry and dissection. A technique is described where stented polytetrafluoroethylene grafts were used to shield right internal mammary artery pedicles. There were no operative deaths or polytetrafluoroethylene-related complications. The right internal mammary artery was patent with its target vessel well perfused in 6 restudied patients.

Determinants of operative mortality in reoperative coronary artery bypass grafting

Previously suggested risk factors for operative mortality in reoperative coronary artery bypass grafting are contradictory. Therefore, we analyzed our data of 622 patients who underwent reoperative bypass grafting from January 1986 through June 1993. Among these patients, 258 had saphenous vein grafts alone and 364 had internal mammary artery grafting, including unilateral (342 patients) and bilateral (22 patients) mammary artery grafting with or without additional saphenous vein grafting. Overall operative mortality was 11.4% for reoperation compared with only 3.6% for primary bypass grafting during the same time frame. To determine risk factors for mortality and the influence of internal mammary artery grafting on the outcome, we analyzed 82 variables (31 preoperative, 17 intraoperative, and 34 postoperative) by univariate analysis. Significant variables or the variables having a trend (p < 0.2) to be associated with the mortality were included in stepwise multiple logistic regression analyses. Two regression analyses were separately performed. Regression 1 only included preoperative and intraoperative variables whereas regression 2 included postoperative variables as well. The logistic regressions demonstrate that preoperative variables (low ejection fraction [p = 0.0002], old age [p = 0.003], female gender [p = 0.011], and history of arrhythmia [p = 0.023]), intraoperative variables (emergency operation [p = 0.0001] and long perfusion time [p = 0.0001]), and postoperative variables (complications) are independently associated with higher mortality. Unlike previously described results, aortic crossclamp time, route of cardioplegia, use of internal mammary artery, number of grafts, and year of operation are not associated with operative mortality. The identification of these risk factors may have important implications in further improvement of the results of reoperative coronary artery bypass grafting.

Late endothelial function of free and pedicled internal mammary artery grafts

The internal mammary artery has greater long-term patency than the saphenous vein when used for coronary bypass grafting. Therefore, bilateral use of the internal mammary artery for grafting with the right internal mammary artery used as a “free” graft may result in improved graft survival. The study objectives were to compare the endothelial-dependent and -independent vasodilatory response in free and pedicled internal mammary artery grafts in patients who had previously undergone coronary surgery. Free (group 1, n = 8) and pedicled (group 2, n = 7) internal mammary artery grafts were studied by comparing the response to selective infusion of the endothelial-dependent vasodilator substance P (1.4 up to 22.4 pmol/min in doubling dose increments) followed by isosorbide dinitrate (2 mg over 2 minutes), in patients undergoing coronary angiography, 1 month to 6 years after coronary surgery. Maximal dilatory response to substance P was 8.7% ± 1.8% in pedicled grafts compared with 8.8% ± 2.3% in free grafts ( p = not significant), with the dose response for both groups being similar. Infusion of isosorbide dinitrate produced only minimal further dilatation in both groups. No significant difference was found in endothelium-dependent and -independent vasodilatory response between free and pedicled internal mammary artery grafts, suggesting that the use of the free right internal mammary artery and other arterial grafts may enhance graft survival. (J T HORAC C ARDIOVASC S URG 1995;110:453-62)

Operative Risk Assessment in Coronary Artery Bypass Surgery, 1990-1993: Evaluation of Perioperative Variables

Patient characteristics and the results of cardiac surgery change with time. To achieve the best possible treatment a continual analysis of results is necessary. The present study analyzes 1225 consecutive patients undergoing isolated aortocoronary bypass surgery for the four-year period ending September 1993. Average age was 63 years (range 32-86 years), 927 (75.7%) patients were male and 298 (24.3%) were female. Hospital mortality was 2.2% (17/787) for elective surgery, 6.3% (21/336) for urgent surgery, and 9.8% (8/82) for emergency surgery. Intraoperative variables increasing independently operative mortality as evidenced by multivariate analysis were the following: prolonged aortic cross-clamping time (p < 0.0001), absence of cold-blood cardioplegia (p = 0.0012), absence of bilateral use of internal mammary artery (p = 0.0035). Likewise, intraoperative variables influencing major adverse outcome (operative mortality and/or need for intra-aortic balloon pulsation) were the following: prolonged aortic cross-clamping time (p < 0.0001), absence of cold-blood cardioplegia (p = 0.0360). In conclusion, global ischemic time was the dominant variable in predicting operative outcome. Furthermore, a protective effect of cold blood cardioplegia and bilateral internal mammary artery grafting was evidenced.

Use of internal mammary artery for emergency grafting after failed coronary angioplasty

Of 929 consecutive patients who underwent percutaneous transluminal coronary angioplasty over a 96-month period, 32 (3.4%) had emergency coronary artery bypass grafting for angioplasty failure. Twenty-two patients (69%) were hemodynamically stable (stable group), and 10 (31%) were unstable (unstable group) before emergency bypass. In the unstable group, the interval between failed angioplasty and opening of the grafts or end of extracorporeal circulation was significantly shorter ( p < 0.001 and p < 0.002, respectively) and significantly more grafts per patient were performed ( p < 0,05) than in the stable group. Twenty-seven patients (84%) received at least one internal mammary artery graft, independent of their hemodynamic condition. In 11 culprit left anterior descending arteries, the internal mammary artery graft wad supplemented by a saphenous vein graft to the same territory, especially in the unstable group. There were no hospital deaths. Postoperatively, the incidence of myocardial Infarction ( p < 0.005) and the use of antiarrhythmics ( p < 0.0001) were increased and length of stay tended to be longer in the unstable compared with the stable group. The use of a leperfusion catheter had no influence on clinical outcome, except for a significantly reduced postoperative use of antiarrhythmics ( p < 0.05). The internal mammary artery can be used in emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty, without hospital mortality and with acceptable morbidity, especially in hemodynamically stable patients.

Arterial revascularization with the right gastroepiploic artery and internal mammary arteries in 300 patients

From September 1989 to September 1992, the right gastroepiploic artery in combination with one or both internal mammary arteries was used as a graft in 300 patients who underwent coronary artery bypass grafting. The gastroepiploic artery was the primary choice in preference to the saphenous vein. The study comprised 263 men and 37 women, ranging in age from 31 to 77 years (median age 59 years). Thirty-nine patients (13%) underwent previous bypass procedures with autologous vein grafts. In 17 patients (5.7%) the gastroepiploic artery was used as a single graft. In 150 patients (50%) the gastroepiploic artery in conjunction with one internal mammary artery was used (in 6 patients combined with a vein graft). In 133 patients (44.3%) the gastroepiploic artery was used with both internal mammary arteries. Revascularization in nine patients (3%) was combined with another cardiac procedure; three aortic valve replacements, two mitral valve repairs, and four resections of a left ventricular aneurysm. Ten patients died in the hospital (3.3%; 70% confidence limits 2.3% to 4.8%); two of these patients had an infarction in the area revascularized by the gastroepiploic artery. At late follow-up, 0.5 to 39 months (mean 14 months) after the operation, we found no mortality. One patient with an occluded gastroepiploic artery graft underwent reoperation with the use of the right internal mammary artery. One patient underwent percutaneous transluminal coronary angioplasty of the right coronary artery after occlusion of the gastroepiploic artery. Elective recatheterization was done in 88 patients 1 to 25 months after operation (mean 10 months). Graft patency in gastroepiploic artery grafts increased steadily from 77% in the first semester of the study to 95% in the fourth semester and then equaled the patency of the internal mammary artery grafts (97%), which was almost constant during the whole period. We conclude that patency of the gastroepiploic artery was initially related to a "learning curve" but eventually equaled that of the internal mammary artery grafts. Furthermore, the gastroepiploic artery may well be the graft of choice in conjunction with the internal mammary arteries.

Impact of internal mammary artery conduits on operative mortality in coronary revascularization

The long-term advantages of internal mammary artery (IMA) conduits in cotonary artery bypass graft (CABG) procedures are widely recognized, but the immediate short-term impact of IMA grafts is not well defined. The purpose of this study was to investigate the influence of IMA conduits on CABG operative mortality (OM). A retrospective study of two groups of patients undergoing isolated CABG was performed. Patients having at least one IMA graft (group 1) were compared with those with only venous conduits (group 2). The patient population was taken from The Society of Thoracic Surgeons National Cardiac Surgery Database, which contains a broad multiinstitutional experience. A total of 38,578 registered patients undergoing isolated CABG from 1987 through 1991 were studied. Of these, 18,614 patients had at least one IMA conduit (group 1), whereas 19,964 had CABG using entirety venous conduits (group 2). The OM for group 1 was 2.0% ( 365 / 18,614 ), whereas the mortality was 4.5% ( 903 / 19,964 ) for group 2 ( p < 0.005). Patient sub-groups were examined to determine if the improved OM associated with IMA grafting was present in these patient subsets. The population was broken down according to age, sex, ejection fraction, extent of coronary disease, and operative priority. For each subset, univariate analysis showed that group 1 OM was significantly less ( p < 0.005) than the OM for group 2. Numerous combinations of these patient parameters were also analyzed. Group 1 patients had a significant ( p < 0.05) improvement in OM in each combination except for patients more than 70 years of age requiring reoperations. Multivariate analysis also demonstrated that the use of an IMA was independently associated with improved patient survival ( p < 0.0025). To consolidate the net effect of numerous patient risk factors, a Bayesian risk model was used to stratify patients into risk quartiles. For the lowest risk quartile (predicted OM <1.14%) there was no significant difference in group 1 versus group 2 patients. For every other risk category, there was a significant improvement in OM associated with IMA use ( p < 0.005). We conclude that in the vast majority of patient subsets, IMA conduits are associated with a statistically significant improvement in OM when compared with use of venous conduits alone.

The use of bovine internal mammary artery (Bioflow) grafts in coronary artery surgery.

Over a 3-year period 17 patients underwent a total of 25 coronary artery bypass grafts utilising bovine internal mammary artery [BIOFLOW]. Three patients died in the peri-operative or early post-operative period allowing detailed information to be gathered on 14 patients. Seven patients who had had a total of 11 Bioflow grafts implanted underwent post-operative coronary angiography at a mean time of 19 months after surgery revealing occlusion in all the Bioflow grafts. Two patients who underwent aortic valve replacement combined with single Bioflow grafts were symptom-free and refused re-study. Two patients who had three coronary grafts each, including single Bioflow grafts, refused re-study though one of them had recurrent anginal symptoms. Two patients, one with recurrent anginal symptoms, who had a total of four Bioflow grafts were considered unfit for restudy on medical (non-cardiac) grounds. One patient with two Bioflow grafts and recurrent symptoms refused long-term follow-up. Despite reports of good early patency rates with the Bioflow graft, we have not found this to be the case even when patients were anticoagulated post-operatively. We do not recommend the use of this graft as early occlusion is to be expected, which may result in an early return of anginal symptoms.

Use of internal mammary artery in myocardial revascularization after mediastinal irradiation

Ten patients with radiation-associated proximal coronary artery disease underwent myocardial revascularization. In seven patients (group A) the internal mammary artery was used and in the other three (group B) only venous conduits were used. Except for mild adhesions between the pericardium and the epicardium, no unusual technical problems were encountered. In all patients in group A the internal mammary artery exhibited excellent flow, and histologic examination in two patients revealed a normal intima and media with only slight fibrosis of the adventitia. In two patients in group B, fibrosis of the internal mammary artery precluded its use, whereas the third patient had contraindications prohibiting use of the internal mammary artery. Long-term follow-up (range 6 to 72 months) revealed that one patient in group A died late of metastatic disease, and of the remainder (nine patients), seven were in New York Heart Association class I and two were in class II. Preoperative assessment of the internal mammary artery by angiography or, alternatively, B-mode imaging with Doppler spectrum analysis is recommended in patients with radiation-induced coronary artery disease who are scheduled to undergo myocardial revascularization with intended use of the internal mammary artery. In our experience, despite previous exposure to irradiation, the internal mammary artery should still be considered as a viable conduit for myocardial revascularization when preoperative assessment shows patency.

Sonographic Measurement of Diaphragmatic Motion after Coronary Artery Bypass Surgery

Forty-eight patients were prospectively evaluated following coronary artery bypass grafting (CABG) in order to determine values for diaphragmatic mobility by sonography, to compare diaphragmatic motion to chest x-ray findings, to relate diaphragmatic motion to pulmonary function tests, and to determine whether use of the left internal mammary artery (LIMA), aortic cross-clamp time, or other clinical variables were predictive of diaphragmatic dysfunction. Mean left diaphragmatic motion was 2.8 +/- 1.1 cm (range, 1.0 to 5.7 cm), mean right diaphragmatic motion was 3.9 +/- 1.1 cm (range, 1.8 to 6.4 cm), and ratio of left to right motion was 0.74 +/- 0.27 (range, 0.19 to 1.4). Forty-one patients had normally positioned diaphragms on the chest x-ray film; four of these had poor mobility by ultrasonography (< 1.6 cm). Of the seven elevated left hemidiaphragms on chest x-ray films, three had an excursion of 1.6 cm or more by ultrasonography. The mean FVC for all patients was 59 +/- 13 percent of predicted. There was no relationship between diaphragmatic mobility and FVC or negative inspiratory pressure. The diaphragmatic motion in 36 patients having LIMA grafting was similar to those without (2.7 +/- 1.2 cm [n = 36] vs 2.8 +/- 0.8 cm [n = 12], respectively). Aortic cross-clamp time and respiratory symptoms also did not correlate with diaphragmatic mobility. Sonography can be used in the evaluation of diaphragmatic motion after CABG and may be more accurate in detecting a poorly mobile diaphragm than is the chest x-ray film.

Use of the Internal Mammary Artery for Myocardial Revascularization in a Patient With Radiation-Induced Coronary Artery Disease

A 9-year-old boy with clinical stage IIA Hodgkin's disease underwent radiotherapy to the neck and mediastinum. Twenty-two years later, he sought medical attention because of angina pectoris. Cardiac catheterization revealed proximally located high-grade stenoses of the left main, left anterior descending, circumflex, and right coronary arteries. He underwent coronary artery bypass grafting with use of the left internal mammary artery to the left anterior descending coronary artery and reversed saphenous vein grafts to the circumflex and right coronary arteries. The postoperative course was uncomplicated. Previous radiotherapy to the mediastinum should be considered a risk factor for the development of premature coronary artery disease. Surgical revascularization is the preferred method of management. A combination of an internal mammary artery graft and a saphenous vein graft should be used in young patients.