Left Internal Mammary Graft Research Articles

Acute effects of 17β-estradiol on left internal mammary graft after coronary artery bypass grafting

Background. Vasospasm of arterial conduits used for coronary surgical procedures is an important cause of postoperative graft failure. Mounting experimental evidence suggests that estrogen reverses acetylcholine-induced vasospasm of the coronary arteries in animals and humans. Estrogen also affects endothelium-derived constrictor factors. We therefore investigated the in vivo vasomotor responses to transdermal 17β-estradiol of the left internal mammary artery (LIMA) grafted on the anterior descending coronary artery. Methods. We studied 20 women, mean age of 62 ± 7.2 years (range, 48 to 73 years), who had undergone cardiopulmonary bypass for coronary artery bypass grafting. They received transdermal 17β-estradiol on the fifth day after operation. The diameter, cross-sectional area, and blood flow of the LIMA graft were measured by transthoracic color Doppler echography before (basal values) and after the transdermal administration of 50 μg of 17β-estradiol (control). Results. LIMA graft vasodilation after the administration of 17β-estradiol was observed. A significant increase in diameter (2.06 ± 0.4 mm versus 2.37 ± 0.28 mm; p = 0.035) and cross-sectional area (3.45 ± 1. 2 mm 2 versus 4.24 ± 1 mm 2; p = 0.039) was registered. The LIMA graft mean flow increased by 49% (44.76 ± 27.19 mL/min versus 56.62 ± 27.69 mL/min), but this increase was not statistically significant ( p = 0.06). Conclusions. The acute postoperative transdermal administration of 17β-estradiol induced a significant increase of LIMA graft diameter and cross-sectional area in postmenopausal women who underwent coronary artery bypass grafting. The LIMA graft vasodilation was also associated with an improvement in LIMA blood flow.

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.

Conservative management of postoperative chylothorax using somatostatin

Chylothorax is a rare but serious postoperative complication of thoracic surgical procedures. We report the case of a 77-year-old man who underwent a coronary artery bypass procedure using a left internal mammary artery pedicle graft. A permanent pacemaker was required postoperatively. A persistent postoperative chylothorax developed necessitating continuous drainage and conservative management. Somatostatin was instituted when after 1 week this management failed to resolve the chylothorax. This led to rapid cessation of chyle production. Enteral feeding was reinstituted without complication and surgical intervention was avoided.

Isolated Left Anterior Descending Coronary Artery Disease

Background —Single-vessel coronary artery disease is usually treated with PTCA; however, this approach when applied to the left anterior descending coronary artery (LAD) is hampered by high restenosis rates, often approaching 50%. Coronary stenting (STENT) and left internal mammary artery bypass grafting of the LAD (LIMA-LAD) are other options that have been successfully used for single-vessel LAD disease. The optimal mode of revascularization for patients with isolated single-vessel LAD disease is unclear. The purpose of the present study was to examine PTCA versus STENT versus LIMA-LAD with respect to short- and intermediate-term outcomes. Methods and Results —This was an observational retrospective cohort study comparing in-hospital and intermediate-term outcomes and functional class among patients with isolated single-vessel LAD disease revascularization. Consecutive eligible patients were grouped according to their initial revascularization procedure and systematically followed up. A total of 704 patients qualified for the study: 469 in the PTCA group, 137 in the STENT group, and 98 in the LIMA-LAD group. Follow-up data were complete for 97% of patients and averaged 27±13 months. In-hospital mortality for the PTCA, STENT, and LIMA-LAD groups was 1.1%, 0%, and 0% ( P =0.51), respectively. Median hospital stays after the procedure for the respective treatment groups were 1, 1, and 5 days ( P <0.001), and occurrences of in-hospital myocardial infarction were 0.9%, 1.5%, and 1.0% ( P =NS). Repeat revascularization procedures were performed in 30%, 24%, and 5% of the PTCA, STENT, and LIMA-LAD groups ( P =<0.001 for LIMA-LAD versus other groups, P =0.11 for PTCA versus STENT). Actuarial 2-year mortality was 3.9%, 2.6%, and 1% in the PTCA, STENT, and LIMA-LAD groups ( P =0.33). Conclusions —Revascularization for isolated LAD disease using PTCA, STENT, or LIMA-LAD results in low in-hospital adverse event rates and good long-term results. Repeat procedures are required less often after LIMA-LAD than after either PTCA or STENT. Long-term mortality was not statistically different, but the trend was for the lowest mortality with LIMA-LAD, a somewhat higher mortality with STENT, and the highest mortality with PTCA.

Radial artery in CABG: could the early results be comparable to internal mammary artery graft?

Background. The accidental detection of patency of radial artery grafts, by Acar, which had been labeled as blocked 18 years earlier, has led to its revival as a conduit in coronary artery bypass surgery. We used radial artery as one of the grafts in 287 patients from February 1996 to June 1998. Here we present our early clinical experience and the midterm angiographic follow up of the initial 62 patients. Methods. A no touch, atraumatic harvesting technique coupled with gentle hydrostatic and pharmacological dilatation of the radial artery graft was employed. Radial artery was used to revascularize coronary vessels with >80% proximal stenosis. Postoperatively, the patients were administered a low dose nifedipine that was continued for 6 months thereafter. The patients were followed up clinically after discharge from the hospital and angiographic evaluation of the grafted radial artery by selective injection was done at a mean interval of 16.2 ± 5.1 months (3–24 months) postoperatively. Results. There was no perioperative or late myocardial infarction or mortality. No significant complications related to the harvesting of radial artery were encountered. Angiographically, the radial artery grafts were found to be patent in 96.8% of patients (60/62). Mild distal anastomotic narrowing was seen in angiogram of one patient with good filling of the target vessel. Another patient showed diffuse spasm of radial artery graft. The patency of the pedicled left internal mammary grafts was also 98.2% (56/57). All the patients were asymptomatic. Conclusions. Radial artery seems to be an excellent alternate arterial conduit for myocardial revascularization with early and midterm patency rates equivalent to that of pedicled internal mammary artery, and it should be used more often for myocardial revascularization as an adjunct to pedicled internal mammary artery graft.

Detección mediante Doppler color de los puentes de arteria mamaria interna y valoración funcional de su permeabilidad

Left internal mammary artery coronary graft patency is usually evaluated invasively by cardiac catheterization. The objective of this study was to assess the ability of a high-frequency transthoracic Doppler echocardiographic system in the evaluation of patency and flow velocities changes in left internal mammary artery. Twenty-two patients (63 +/- 9 years, 17 male) who had previously undergone left internal mammary artery to left anterior descending artery were evaluated by transthoracic echocardiography, with an Acuson Sequoia C256 equipment (Acuson, Mountain view, USA), placing the transducer (5 MHz) in the second-third left intercostal space. Left internal mammary artery flow was considered to be found in the presence of one systolic/diastolic biphasic blood flow. Dipiridamol 0.5 mg/kg was administered in absence of contraindications in order to evaluate the flow reserve. In 16 patients (73%), a biphasic systolic-diastolic flow was visualized. Peak velocity of systolic and diastolic waves was 38 +/- 13 and 37 +/- 15 cm/s, respectively. Eleven patients received i.v. dipiridamol 0.5 mg/kg. After dipiridamol, systolic and diastolic velocities rose from 32 +/- 8 to 43 +/- 14 cm/s (p = 0.0429) and from 25 +/- 8 to 50 +/- 17 cm/s (p = 0.0002), respectively (an increasing of 33 +/- 22% and 103 +/- 46% over the baseline, respectively). This descriptive study shows that a non-invasive functional evaluation of left internal mammary artery grafts by a transthoracic approach with a high-frequency echocardiographic equipment is possible.

Evaluación de la permeabilidad de los injertos de arteria mamaria interna izquierda mediante análisis de la velocidad del flujo por técnica Doppler transcutánea

To analyze the features of Doppler flow velocity curve of left internal mammary artery by-pass grafts in relation with their permeability as assessed by selective angiography. Twenty-five consecutive patients with a left mammary artery graft were studied by angiography and transcutaneous Doppler technique. From the Doppler tracings, peak velocity and time-velocity integral of the systolic and diastolic components were determined. Patency of the graft and the characteristics of the distal native coronary artery were evaluated at angiography. Doppler flow signal was obtained in 23 (92%) of 25 analyzed patients. The graft was angiographically patent in 17 (68%) of 25 patients; in 15 (88%) of them the Doppler flow velocity signal was mainly diastolic and in only 2 (12%) it was predominantly systolic. In 8 (32%) of the 25 patients the graft was angiographically occluded, 6 (75%) of these patients showing a predominantly systolic Doppler signal, while the remaining 2 (25%) patients were those in whom the signal could not be elicited. Sensitivity and specificity of a predominantly diastolic Doppler flow pattern for the presence of graft patency was 88% and 100% respectively, with a predictive positive value of 100% and a negative one of 80%. Doppler flow velocity pattern of internal mammary artery by-pass grafts is related with patency of the graft, the presence of a predominantly diastolic curve being highly indicative of a patent graft.

Delayed diagnosis of anomalous origin of the left coronary artery 16 years after mitral valve replacement

Mitral insufficiency caused by ischemia is frequently found in anomalous origin of the left coronary artery from the pulmonary artery. We report a case of a 25-year-old woman who was diagnosed to have anomalous origin of the left coronary artery from the pulmonary artery and had successful left internal mammary artery bypass grafting 16 years after mitral valve replacement for mitral insufficiency of an unknown cause in her childhood.

Lethal Postoperative Coronary Artery Spasm

Background. Coronary artery spasm in the immediate postoperative period after a coronary operation is recognized infrequently. Its severity is variable and manifestations unpredictable. The diagnosis is usually made by an awareness of the possibility and thereafter by exclusion of other causes of myocardial ischemia. An opportunity for a positive diagnosis is rarely available. Methods. The case reports of 3 patients with similar presentations of ischemic heart disease and with severe manifestations of coronary artery spasm in the postoperative period are presented. Results. All 3 patients were women aged 55 to 60 years. All had single-vessel coronary artery disease involving the left anterior descending artery and underwent a left internal mammary artery bypass graft. Severe manifestations of myocardial ischemia of abrupt onset developed approximately 7 hours postoperatively in each patient. One patient died of severe hemodynamic deterioration from which resuscitation was unsuccessful. Another sustained a large anterior myocardial infarction despite graft patency. The third patient was supported by an intraaortic balloon pump and made a full recovery. Conclusions. The early diagnosis of coronary artery spasm is achieved by an awareness of the condition. The institution of early appropriate management may prevent its consequences.

Septal reverse redistribution on TI-201 chloride myocardial SPECT in left internal mammary artery bypass graft

Septal reverse redistribution on TI-201 chloride myocardial SPECT in left internal mammary artery bypass graft

Effectiveness of autologous blood donation in coronary surgery--a retrospective analysis

This study was performed to evaluate whether autologous blood donation prior to coronary artery bypass graft surgery (cabg) reduces homologous blood requirements and the risk of homologous blood transfusion. Within a period of 18 months, 633 patients undergoing cabg surgery were retrospectively included into the study. Non-donors were included if preoperative haemoglobin concentration exceeded 12.5 g%. According to demographic data, risk scores of patients who donated blood (n = 201) were lower. More patients of this group received left internal mammary bypass grafts (63% vs. 51%; p = 0.047). Nevertheless, blood loss did not differ between donors and non-donors. Prior to blood donation, haemoglobin-concentration was significantly higher in male donors (n = 177) compared to female donors (n = 24) (15 +/- 1.2 vs. 13.8 +/- 1 g%; P < 0.001). Compared to female donors, male patients donated significantly more blood units. The risk of homologous blood donation was significantly lower in male donors than in male non-donors (no homologous transfusion: 20% vs. 42%; P < 0.0001; Odds Ratio: 0.34; 95% confidence-interval: 0.23-0.52). Accordingly, homologous blood requirements were lower in male donors (0.9 +/- 3.4 vs. 1.6 +/- 3.6 blood units; P = 0.02). Between female donors and non-donors neither the number of patients treated with homologous blood (no homologous transfusion: 29% vs. 33%, P = 1; odds ratio: 1.17; 95% confidence-interval: 0.4-3.4), nor the mean number of transfused homologous blood units (1.8 +/- 1.6 vs. 1.9 +/- 2.4; P = 0.83) was different. Reactions during blood donation requiring treatment (bradycardia, hypotension, angina, arrhythmias) occurred more often in female patients (5/24 vs. 9/177; P = 0.015). In our study, autologous blood donation significantly decreased the risk of homologous transfusion and homologous blood requirements in male cabg patients. We were not able to prove the efficacy of autologous blood donation in female cabg patients. Due to the small sample size of our investigation, further prospective studies are necessary to answer the question whether patients with low blood volume, body weight and body height scheduled for cabg surgery should be excluded from autologous blood donation.

Treatment of a Left Internal Mammary Graft Ostium Stenosis Using a Palmaz‐Schatz Stent with Intravascular Ultrasound Guidance and Reduced Anticoagulation

A 62‐year‐old man sustained an anterior wall myocardial infarction 7 years following coronary artery bypass graft surgery. The patient underwent successful placement of a Palmaz‐Schatz stent within the ostium of the left internal mammary artery utilizing ultrasound guidance and was discharged in 24 hours with reduced anticoagulation.

Noninvasive Assessment of Left Internal Mammary Artery Graft Patency Using Transthoracic Echocardiography

Cardiac catheterization is the only practical method of assessing internal mammary artery graft patency. A noninvasive method would be useful in patients with recurrence of anginal symptoms after coronary artery bypass graft surgery. We hypothesized that transthoracic echocardiography could provide information on blood velocity and anatomy and therefore has the potential to allow measurement of blood flow. High-frequency (5 MHz) transthoracic echocardiography was performed on 41 consecutive patients (mean age, 67 +/- 6 years) who had had left internal mammary artery grafts to the left anterior descending coronary artery (LAD) and were undergoing coronary angiography because of recurrence of anginal symptoms. The results were compared with those from 19 patients (mean age, 58 +/- 11 years) in whom an ungrafted left internal mammary artery was assessed and with those from 15 patients (mean age, 61 +/- 12 years) who had angiographically normal coronary arteries in whom the LAD was studied. Doppler velocity profiles of the left internal mammary graft were obtained in 35 of the 41 study patients (81%). In all cases, a biphasic pattern of blood flow was recorded that corresponded to systole and diastole. Two different flow patterns were observed. In 25 patients with a normal graft or moderate (< 70%) stenosis (group A), blood flow velocity was maximal during diastole. This pattern was also seen in the LAD control group. In 10 patients with severe (> 70%) graft stenosis (group B), blood velocity was maximal during systole, and low velocities were recorded during diastole. This pattern was also seen in the ungrafted internal mammary artery control group. The diastolic fraction of the velocity time integrals for group A was 0.77 +/- 0.07 and for group B was 0.27 +/- 0.01 (P < .05). A diastolic velocity time integral fraction < 0.5 predicted severe stenosis with a sensitivity and specificity of 100%. The ratio of systolic-to-diastolic peak velocities for group A was 0.54 +/- 0.26 and for group B was 3.45 +/- 0.74 (P < .05). A systolic-to-diastolic peak velocity ratio > 1 predicted severe stenosis with a sensitivity of 100% and specificity of 85%. Mean graft blood flow was 63 +/- 21 mL/min. There was no significant difference in mean blood flow between any of the patient groups studied. High-frequency transthoracic echocardiography allows identification of the left internal mammary grafts and measurement of blood flow. Compared with patent grafts or those with moderate lesions, severe stenoses demonstrated different Doppler velocity patterns. Use of this technique may allow noninvasive detection of significant stenoses of the left internal mammary artery graft.

Assessment of Blood Velocity Profiles in Left Internal Mammary Artery Bypass Grafts Using Transthoracic Doppler Echocardiography

Assessment of Blood Velocity Profiles in Left Internal Mammary Artery Bypass Grafts Using Transthoracic Doppler Echocardiography

Peroperative hemodynamic study of left internal mammary artery grafts.

The present study was undertaken to analyse hemodynamic features of an arterial graft and to determine parameters which influence primarily flow and velocity. A total of 284 consecutive patients having isolated coronary bypass surgery underwent peroperative hemodynamic assessment by pulsed Doppler ultrasonics of a left internal mammary artery bypass graft implanted onto the left anterior descending artery. Internal mammary artery free flow was 109.2 +/- 3.7 ml/min and flow in the internal mammary artery measured after completion of the distal anastomosis was 70.9 +/- 2.7 ml/min. All values quoted are mean +/- standard error of the mean. Mean velocity was 21.2 +/- 0.6 cm/sec, internal diameter was 2.65 +/- 0.04 mm and pulsatility index was 2.24 +/- 0.12. Resistance was expressed as mmHg/(ml . min-1) and averaged 1.65 +/- 0.13 for total resistance, 0.87 +/- 0.05 for graft resistance, and 0.73 +/- 0.13 for coronary resistance. From a set of 35 variables, stepwise multiple regression analysis selected two parameters influencing independently flow in internal mammary artery (R2 = 0.8762): flow velocity (p < 10(-4)) and internal diameter (p < 10(-4)). Variables influencing velocity (R2 = 0.3071) were: pulsatility index, which is a dimensionless expression of peripheral resistance (p < 10(-4)), and free internal mammary artery flow (p = 0.0007). Furthermore, a significant correlation between internal diameter and total resistance was observed (R = -0.5363, p < 10(-4), Y = 1.676X-1.545), and the exponentially fitted regression line was characterized by a marked increase of resistance at diameters less than 2 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Endoluminal stenting of a subclavian artery stenosis to treat ischemia in the distribution of a patent left internal mammary graft

Subclavian artery stenosis is a rare cause of recurrent myocardial ischemia in patients who have undergone left internal mammary-coronary artery bypass grafting. A patient with this syndrome was successfully treated by placement of Palmaz biliary stents in the left subclavian artery. Angiographic and hemodynamic evidence of restricted subclavian flow resolved following stenting, as did the patient's unstable angina syndrome. Endoluminal stenting of the proximal subclavian artery for the treatment of coronary-subclavian steal can be performed safely and provides an alternative to other forms of surgical or percutaneous (PTCA, directional atherectomy) revascularization for treatment of this disorder.

Outcome five years after percutaneous transluminal coronary angioplasty or coronary artery bypass grafting for significant narrowing limited to the left anterior descending coronary artery

Percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) are both used widely for angina but information about their comparative efficacy is limited. This study compared the outcome of 358 consecutive patients undergoing initial revascularization for significant narrowing of the left anterior descending artery (LAD) by PTCA (n = 254) or CABG (n = 104) from 1987 to 1989. PTCA was successful in 93% but complicated by urgent CABG in 3%. A left internal mammary graft was used in 88% of those having elective CABG. There was 1 perioperative death. Follow-up data were obtained after a median interval of 5.5 years (maximum 7.1). Rates for freedom from death (97% PTCA vs 93% CABG, p = 0.06) were similar, but CABG patients had greater rates for freedom from chest pain recurrence (74% CABG vs 48% PTCA, p < 0.0001), myocardial infarction (98% vs 92%, p = 0.04), and from need for further revascularization (99% vs 67%, p < 0.0001). Both groups achieved similar status, with 81% of PTCA and 90% of CABG patients having angina no worse than functional class I. Quality-of-life index was high for both groups ( 0.983 ± 0.034 1.000 vs 0.987 ± 0.032 1.000 , p = 0.3). Both PTCA and CABG result in excellent survival, functional ability, and quality of life, but patients undergoing PTCA require more procedures to achieve this.

Angiographic evaluation of a carotid‐subclavian bypass graft in a patient with subclavian artery stenosis and left internal mammary artery bypass graft

The incidence of coronary subclavian steal syndrome is estimated to be 0.4%. When revascularization is necessary, the preferred technique is the carotid-subclavian bypass graft. Failure of a carotid-subclavian graft is rare. We present a patient with subclavian stenosis who required reevaluation of both the carotid subclavian conduit and the left internal mammary bypass graft. A combined femoral and left brachial approach is recommended for evaluating the carotid-subclavian graft and left internal mammary artery graft in patients with bypassed subclavian artery stenosis and prior myocardial revascularization.

Coronary angioplasty versus left internal mammary artery grafting for isolated proximal left anterior descending artery stenosis

Summary Coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) are more effective than medical treatment for the management of ischaemic heart disease. However, patients with single-vessel involvement have been excluded from prospective comparisons of the two methods. We have carried out such a comparison in patients with isolated proximal left anterior descending artery stenosis, conserved left ventricular function, and documented ischaemia. Eligible patients presenting to a single centre were randomly assigned PTCA (68 patients) or left internal mammary grafting (66). The procedures were technically feasible in all cases. The incidence of in-hospital complications was 2% (perioperative myocardial infarction) for CABG and 3% (emergency CABG for acute closure) for PTCA. Clinical and functional status improved similarly in both groups. However, patients in the PTCA group took more antianginal drugs. At median follow-up of 2·5 years, 86% of CABG-treated and 43% of PTCA-treated patients were free from adverse events (p<0·01; relative risk 2·0 [95% Cl 1·7-2·3]). The adverse events that explain this difference were restenosis (32%) requiring subsequent surgical (16%) or percutaneous (15%) revascularisation (1% had medical therapy). Rates of cardiac death and myocardial infarction did not differ between the groups. Both CABG and PTCA improve the clinical status of symptomatic patients with single-vessel coronary artery disease. If patient and physician accept the risk of restenosis and reintervention associated with PTCA, this procedure remains a suitable option and a simpler initial alternative to CABG.

Anomalous origin of the left coronary artery from the pulmonary artery

A 20-year-old woman underwent successful operative correction of anomalous origin of the left coronary artery from the pulmonary artery by left internal mammary artery bypass graft. The clinical, hemodynamic, and angiographic features of this unusual case are presented. Different therapeutic options are discussed.