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Risks of using internal thoracic artery grafts in patients in chronic hemodialysis via upper extremity arteriovenous fistula.

BACKGROUND: In patients in chronic hemodialysis via upper extremity arteriovenous fistula in whom ipsilateral internal thoracic artery graft was used for myocardial revascularization, hemodynamic interference between the fistula and the graft during dialysis can be hypothesized. METHODS AND RESULTS: In 5 patients undergoing chronic hemodialysis via upper extremity arteriovenous fistula, ipsilateral to an internal thoracic to left anterior descending graft mammary flow was studied by means of transthoracic echo-color Doppler at baseline and during hemodialysis. Flow in the contralateral mammary artery was used as control. Transthoracic echocardiography was performed in concomitance with flow evaluation to assess eventual modifications of left ventricular segmental wall motion. Immediately after hemodialysis pump start there was a marked reduction of peak systolic and end-diastolic velocities and time average mean velocity and flow in the ITA ipsilateral to the fistula, whereas no substantial hemodynamic modification was evident in the contralateral artery. Dialysis-induced reduction of ipsilateral ITA flow was accompanied by evidence of hypokinesia of the anterior left ventricular wall. Three cases also experienced clinical angina. CONCLUSIONS: Hemodynamically evident flow steal and consequent myocardial ischemia develop during hemodialysis in patients with upper extremity arteriovenous fistula and ipsilateral internal thoracic artery to coronary graft. These data have major implications for patients' management, both for nephrologists and cardiac surgeons.

Arteriovenous Shunt, Surgical↗

Ultrasonic assessment of internal thoracic artery graft flow in the revascularized heart.

We investigated the clinical applicability of the transit-time ultrasound technique for quantitation of internal thoracic artery (ITA) graft flow in coronary artery bypass grafting. Intraoperative measurements of arterial and venous coronary graft flow were performed in 63 patients using an ultrasonic flowmeter. Native ITA blood flow was determined using a skeletonized segment of the ITA and a flexible perivascular flow probe. Simultaneous measures of ultrasonic blood flow from the proximal part of the ITA and free flow from the distal cut end of the ITA validated reliability. After coronary grafting, separate perivascular flow probes over the saphenous vein and ITA grafts were positioned to measure flows during cardiopulmonary bypass and immediately before the sternal closure. Mean native ITA flow was 7 +/- 0.8 mL/min and ITA graft flow was 35 +/- 4 mL/min, a fivefold increase after grafting to the coronary artery (p < 0.001). Mean saphenous vein graft blood flow of 38 +/- 4 mL/min was not significantly different from the mean ITA graft flow (p = 0.37). Coronary blood flow via saphenous vein and ITA conduits was unaffected by the cardiopulmonary bypass (p = 0.73). No complications were directly caused by the flow measurements. Flow impedance resulting from pedicle twist at the distal anastomosis was easily detected in 2 patients using the ultrasonic flowmeter. We conclude that ITA graft flow can be quantitated intraoperatively by the transit-time ultrasound technique. Ultrasonic assessment of ITA graft flow in the revascularized heart may be a useful means of detecting immediate coronary graft failure caused by technical errors.

Coronary Artery Bypass↗

Long-term results of bilateral internal thoracic artery grafting.

BACKGROUND: Little is known about the long-term results of the uniform group of patients who had bilateral internal thoracic artery (ITA) grafting with the method of left ITA-to-left anterior descending coronary artery and right ITA-to-circumflex artery. METHODS: Late follow-up study was performed in the first consecutive 203 patients (mean age, 62.6 +/- 9.1 years) who underwent isolated coronary artery bypass grafting with the left ITA anastomosed to the left anterior descending coronary artery and the right ITA to major branches of the circumflex artery. The patients were grouped according to the patency of ITA grafts demonstrated by early postoperative angiography (Both patent (BP) group, 168 patients: both ITAs showed complete patency; Not patent (NP) group, 23 patients: at least one ITA was dysfunctional). RESULTS: Actuarial 7-year survival in all patients was 89.3% +/- 3.1%. The cumulative probability of event-free survival for cardiac death, myocardial infarction, intervention, and angina at 7 years was 96.6% +/- 1.8%, 98.0% +/- 1.5%, 86.7% +/- 3.2%, and 90.7% +/- 2.9%, respectively. NP group had more myocardial infarction and angina than the BP group, but was not statistically significant. Because of failed grafts at the early angiography, intervention was performed more frequently in NP group (p < 0.01). CONCLUSIONS: Our results of actuarial 7-year survival and the cumulative probability of event-free survival were at least comparable to the results of other similar studies using bilateral ITA. The freedom from angina appeared to be better than in the previous study. Overall our study supports the continued use of this method of ITA grafting.

Adolescent↗

Lateral thoracic artery embolization in cystic fibrosis.

We report the embolization of an aberrant origin of haemoptysis - from the internal branch of the lateral thoracic artery - in a patient affected by cystic fibrosis. The technical implications for embolotheraphy in case of an aberrant origin of a haemorrhage are emphasized. Many different systemic arteries may contribute to the blood supply of the lung and many connections may exist between the systemic, bronchial and pulmonary circulations. The presence of non-bronchial systemic arteries supply should be investigated when inconclusive findings are seen during bronchial artery embolization for haemoptysis.

Adult↗

Myocardial revascularization with bilateral internal thoracic artery in patients with left main disease or left ventricular dysfunction: an incremental risk?

Although long-term patency of the internal thoracic artery (ITA) is well stated, there is still some concern about its perioperative performance. We considered 122 consecutive patients, 63 with left main disease (LMD; mean age 60 years) and 59 with left ventricular dysfunction (LVD; mean age 59 years) who underwent coronary artery bypass grafting in our Institute from March 1988 to September 1992. Patients with LMD were divided into 2 groups: LMD I: 29 patients receiving only ITA grafts on the left coronary system and LMD II: 34 patients having a single ITA graft on the left coronary system. Patients with LVD were divided into: LVD I: 44 patients operated with bilateral ITA and LVD II: 15 patients receiving a single ITA graft. Perioperative complications in LMD I and LMD II patients were respectively: myocardial necrosis in 2 (6.9%) versus 3 (8.8%), use of intra-aortic balloon pump (IABP) in 2 (6.9%) versus 2 (5.9%); no death occurred in both groups. Perioperative results in groups LVD I and LVD II were: death in 1 patient (2.2%) versus 1 (6.7%), myocardial necrosis in 2 (4.5%) versus 1 (6.7%) and IABP in 4 (9.1%) versus 2 (13.3%). In our experience the use of bilateral ITA grafts in patients with LMD and LVD was not related to an incremental risk. We conclude that LMD and LVD should not be considered as contraindications to the extensive use of arterial conduits.

Aged↗

Bilateral internal thoracic artery harvesting under robotic video-assistance.

BACKGROUND: Following upon the recent development of minimally invasive coronary robotic surgery, we set out to evaluate the feasibility of bilateral internal mammary artery (IMA) harvesting using the voice-controlled AESOP 2000 video assisted robot. METHODS: The robot is placed on the right side of the patient. The left IMA is first totally video-harvested, with the arm of the robot crossing over the patient to reach the left chest. The voice-controlled movement of the arm allows the surgeon to obtain the best video image of the artery. After completion of the dissection, the arm is positioned on the right part of the chest. The right IMA is then harvested using the same technique. RESULTS: Two patients underwent harvest of a bilateral IMA using this technique. The time of dissection was 52 min and 86 min, respectively. CONCLUSION: This technique allows a more precise, faster, tremor-free dissection, as compared to a conventional thoracoscopic harvesting.

Adult↗

Supraclavicular control of patent internal thoracic artery graft flow during aortic valve replacement.

BACKGROUND: The mortality and morbidity of aortic valve replacement (AVR) after prior coronary artery bypass surgery (CABG) with patent left internal thoracic artery (LITA) is significant. The risk of LITA injury and inadequate myocardial preservation during the cross-clamp period may cause myocardial pump failure. METHODS: A total of 43 patients with a patent LITA graft underwent AVR. The patients were divided into the two groups. Group 1 included 19 patients who underwent AVR with deep hypothermia (20 degrees C) without LITA clamping. Group 2 included 24 patients in whom LITA flow was controlled through supraclavicular occlusion and AVR performed with moderate hypothermia (28 degrees C). RESULTS: Average cardiopulmonary bypass time (CPB) time was 118.79 +/- 20.36 minutes in group 1 and 102.67 +/- 9.66 minutes in group 2 (p = 0.006). Average cross-clamp time was 53.79 +/- 7.26 minutes in group 1 and 49.63 +/- 6.7 minutes in group 2 (p = 0.022). Inotropic support was required in 12 patients in group 1 and 4 patients in group 2 (p = 0.002). Average intensive care unit stay was 4.68 +/- 2.24 days in group 1 and 2.29 +/- 0.46 days in group 2 (p < 0.001). Average hospital stay was 11.84 +/- 2.91 days in group 1 and 8.04 +/- 2.38 days in group 2 (p < 0.001). Mortality due to myocardial failure developed in 4 patients in group 1 but in none of the patients in group 2 (p = 0.02). CONCLUSIONS: Proximal control of LITA flow by extrathoracic supraclavicular occlusion reduces the incidence of myocardial failure due to nonhomogenous cardioplegia delivery to the anterior wall of the heart, resulting in improved myocardial protection and the elimination of the need for deep hypothermia.

Aged↗

[Noninvasive hemodynamic assessment of internal thoracic artery grafts using duplex echocardiography from supraclavicular fossa--a comparison with Doppler catheter method].

We evaluated the usefulness of noninvasive hemodynamic assessment of internal thoracic artery grafts (ITAGs) using duplex Doppler echocardiography from the supraclavicular fossa (transcutaneous pulsed Doppler method: PD method). Eighteen ITAGs were examined by PD method in comparison with Doppler catheter method using Doppler flowire (DC method). The hemodynamic indices used were the diastolic/systolic peak velocity ratio (DSVR) and the diastolic fraction of time-velocity integral (DF) in the ITAGs. A significant linear correlation was seen both in DSVR and DF between these two methods (p < 0.01). The subjects were assigned to two groups according to angiographic findings Group A (Gr-A: 5 grafts) with string sign including significant graft stenosis and group B (Gr-B 13 grafts) with good patency. In both PD and DC methods, DSVR and DF were significantly lower in Gr-A than in Gr-B (p < 0.01). The blood flow pattern was thus systolic dominant in the grafts with string sign, while it was diastolic dominant in the grafts with good patency. In some grafts in Gr-B, however, both DSVR ad DF were as low as that in Gr-A. Responding to pacing, Gr-B further increased both DSVR and DF, but Gr-A did not. As a result, the difference between both groups was further distinguished. In summary, ITAG function can be assessed by the noninvasive PD method. Interventions such as exercise, dobutamine infusion may make it more accurate, particularly in evaluating borderline data.

Aged↗

[Use of intravenous hyperalimentation catheter to drainage prolonged postoperative pleural effusion after harvesting the internal thoracic artery].

Increased chest drainage, a higher incidence of pleural effusions in the postoperative period, and more chest tube drainage was found after harvesting the internal thoracic artery (ITA). Patients with these complications required thoracocentesis, or prolonged chest tube drainage. But these methods may be painful and make a limitation to activity of daily life (ADL) in these patients. We therefore sought an effective procedure for these patients, and applied pleural placement of intravenous hyperalimentation catheter. This technique could drain the effusion completely, conveniently and painlessly without a limitation to ADL. Pneumothorax, infections and other complications occurred in no patients. We concluded that this method might be useful in these patients with prolonged post operative pleural effusion after harvesting the ITA who have failed other modes of therapy.

Aged↗

[Adverse effect of internal thoracic artery steal on perioperative hemodynamic condition--a report of three cases].

In three patients who had suffered from perioperative hemodynamic deterioration after myocardial revascularization with an internal thoracic artery to the left anterior descending coronary artery (LAD), blood steal from the ITA into large side branches was strongly suspected. In two of them an intractable ventricular fibrillation occurred before closure of the chest. Additional insertion of saphenous vein graft to the LAD enabled them to get out of jeopardy. Postoperative angiographic studies demonstrated large pericardial branches which had several fistulous communications with the pulmonary circulation. The other suffered from anteroseptal myocardial infarction immediately after an uneventful operation. Postoperative angiography revealed an enlarged lateral costal branch which gave off four intercostal arteries. Careful and meticulous harvesting of the ITA is mandatory to avoid tragic consequences caused by its large side branches.

Hemodynamics↗

Usefulness of high-frequency transthoracic Doppler echocardiography in noninvasive diagnosis of the left internal thoracic artery graft stenosis at the anastomosis.

BACKGROUND: Stenosis of the left internal thoracic artery (LITA) graft, which usually occurs at the site of the anastomosis, can be noninvasively evaluated by the flow pattern in the proximal graft, but the flow pattern is influenced by several other factors. METHODS AND RESULTS: In the present study, LITA graft flow was investigated by high-frequency transthoracic Doppler echocardiography in 75 consecutive patients who underwent postoperative angiography of the LITA graft. The flow velocity was measured at both the anastomosis and proximal to it, and compared with the quantitative angiographic results. Flow at both sites was detected in 61 (81%) of the 75 patients. The diastolic velocity ratio of the anastomosis to the proximal site correlated with the percent diameter stenosis at the anastomosis. A diastolic velocity ratio >2.0 had a high sensitivity, specificity, positive predictive value and negative predictive value for the presence of significant stenosis at the anastomosis of a LITA graft. CONCLUSIONS: High-frequency transthoracic Doppler echocardiography can be used for the noninvasive diagnosis of LITA graft stenosis.

Aged↗

[Assessment of left internal thoracic artery grafts by atrial pacing].

The flow reactivity of a left internal thoracic artery graft (LITAG) in response to atrial pacing was evaluated in 14 patients who underwent coronary artery bypass grafting (CABG) with LITAG to left anterior descending artery (LAD). Systolic peak velocity and diastolic peak velocity were recorded using a duplex scanner of 7.5 MHz, and flow volumes in each phase and flow ratio were calculated. The external temporary atrial pacing was used to increase heart rates 25 and 50%. Diastolic peak velocity and flow volume increased predominantly on both pacing rates. In contrast, systolic peak velocity decreased when heart rate was raised 50%, and there was no significant difference between the pacing modes in systolic flow volumes. As a result, flow ratio increased predominantly on both pacing rates. Based on the present studies, there may be some advantages with atrial pacing to increase the LITAG flow in response to the myocardial oxygen demand.

Aged↗

Robotically assisted versus conventional freehand technique during beating heart anastomoses of left internal thoracic artery to left anterior descending artery.

BACKGROUND: Although robotically assisted coronary arterial anastomoses are being performed clinically, the short-term and long-term quality and integrity of the left internal thoracic artery (LITA) to left anterior descending artery (LAD) anastomosis remains unknown. The goal of this study was to perform a histologic and angiographic assessment of porcine beating heart LITA to LAD anastomoses using either robotic assistance or a conventional freehand technique. METHODS: Twelve pigs underwent beating heart LITA to LAD anastomoses using either the robotically assisted (n = 6) or conventional freehand techniques (n = 6). Quantitative histologic analysis was performed in all animals in order to determine the degree of vascular wall damage. Selective coronary arteriography was performed in all animals immediately after the procedure in order to evaluate anastomotic patency. The unpaired Student's t test was used for all comparisons between groups. RESULTS: There were no differences in vascular wall damage between the robotically assisted and freehand techniques. Postoperative angiography revealed no stenoses in either group. CONCLUSIONS: Use of the robotically assisted technique for creation of a LITA to LAD anastomosis was not associated with increased histologic damage when compared with the freehand technique in a beating heart porcine model. Furthermore, there was no difference between the two techniques in postoperative patency rate. These results support further clinical investigation of robotically assisted coronary bypass surgery.

Anastomosis, Surgical↗

Leg ischaemia following bilateral internal thoracic artery and inferior epigastric artery harvesting.

There is increasing evidence that the use of arterial conduits for coronary artery bypass grafting provides superior long-term results when compared to using saphenous veins alone. Major complications of using internal thoracic arteries (ITAs) and inferior epigastric arteries (IEAs) are uncommon. We report the case of a 42-year-old man who underwent coronary revascularisation in which harvesting of these arteries resulted in critical ischaemia of the lower limbs requiring aortobifemoral grafting. This patient had a long-standing occluded abdominal aorta which was asymptomatic and relied on the ITAs and IEAs as important collateral blood supply to the legs. The enormous size of these conduits found at operation suggested their role. Management strategies to avoid such a serious complication are discussed.

Abdominal Muscles↗

Angiotensin-converting enzyme inhibitors reveal non-NO-, non-prostacycline-mediated endothelium-dependent relaxation in internal thoracic artery of hypertensive patients.

BACKGROUND: We have shown that treatment of hypertension with ACE inhibitors (ACE-I) enhances relaxation to acetylcholine in human internal thoracic artery (ITA) above this in nonhypertensive patients receiving no ACE-I. Present study assesses the endothelium-dependent responses mediated by neither NO nor prostacyclin in human ITA. METHODS: We compared isolated ITA rings from hypertensive patients treated with ACE-I (ACE-I group) with those from normotensive patients on no ACE-I (control group). Relaxation to acetylcholine was assessed before and after inhibition of NO synthase and cyclooxygenase with L-NMMA and indomethacin, respectively. RESULTS: The maximal relaxation in ACE-I group was 79+/-3.3% and was depressed by incubation with L-NMMA and indomethacin to 41+/-2.7% (p<0.001); pD(2)=7.7+/-0.1 vs. 7.4+/-0.8 (p=0.265). The maximal relaxation to acetylcholine was lower in the control group: 65+/-3.3% (p=0.01); pD(2)=7.5+/-0.1 (p=0.07). Incubation with L-NMMA and indomethacin produced contraction to acetylcholine with a maximum of 43+/-7% (p<0.001); pD(2)=5.3+/-0.3 (p<0.001). The area under the concentration-response curve for acetylcholine-induced relaxation in ACE-I group equaled [arbitrary units] 596+/-71 and after incubation with L-NMMA and indomethacin 281+/-40 (p=0.002). Estimated LNMMA- and indomethacin-resistant relaxation, absent in control group, accounted for 47+/-4% of relaxation to acetylcholine in ACE-I group. Estimated NO- and prostacyclin-mediated relaxation was higher in control group than ACE-I group: 628+/-74 vs. 315+/-47 (p=0.009). CONCLUSIONS: The results suggest that therapy with ACE-I improves endothelial function of hypertensive patients mainly by enhancing the endothelium-derived hyperpolarizing factor (EDHF) (and not NO)-mediated responses. It seems that it reveals measurable non-NO- non-PGI-mediated endothelium-dependent relaxation otherwise absent in conduit arteries.

Angiotensin-Converting Enzyme Inhibitors↗

[Noninvasive assessment of left internal thoracic artery graft patency using transthoracic echocardiography].

To evaluate the utility of transthoracic echocardiography (TTE) for assessing the long-term patency of left internal thoracic artery (LITA) grafts, 36 patients who had coronary artery bypass grafting (CABG) were examined simultaneously for graft flow velocity by TTE and by graft angiogram. The flow velocity in the LITA graft was clearly visualized by TTE in 25 patients from the left supraclavicular echo view. On the basis of the angiogram, the sensitivity and specificity of TTE in the diagnosis of LITA graft patency were 71.4% and 100%, respectively. These 25 patients (mean follow-up time after CABG-29.6 months) were divided into 3 groups according to their preoperative diagnosis and the presence of grafts stenosis by angiogram as follows: APS(-), angina pectoris without graft stenosis in 15 cases; APS(+), angina pectoris with graft stenosis in 2 cases; OMI, old myocardial infarction without graft stenosis in 8 cases. The peak flow velocity D/S ratio and time velocity integral D/S ratio in the APS(-) group (2.48 +/- 0.73, 3.21 +/- 0.89) were significantly (p < 0.01) higher than those in the APS(+) group (0.30 +/- 0.23, 0.35 +/- 0.21) or in the OMI group (0.96 +/- 0.44, 0.87 +/- 0.51). Peak flow velocity D/(S+D) and time velocity integral D/(S+D) ratios in the APS(-) group (0.70 +/- 0.05, 0.75 +/- 0.06) were significantly (p < 0.01) higher than those in the APS(+) group (0.22 +/- 0.14, 0.25 +/- 0.11) or in the OMI group (0.46 +/- 0.17, 0.43 +/- 0.18).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Revascularization with bilateral internal thoracic artery grafts in patients with left main coronary stenosis.

Left main occlusive disease (LMD) is a potentially fatal lesion which is optimally treated with surgical revascularization. Although the internal thoracic artery (ITA) is recognized as having superior long term patency, there has been concern regarding possible flow limitation. Because of this concern, there may be reluctance to use only this conduit in patients with LMD in whom high graft flows are desirable. From 1985 to 1990, 45 patients (38 males, 7 females) with LMD ranging in age from 37 to 75 years (mean 55.9 +/- 8.7) underwent revascularization using bilateral ITA grafts placed to the left anterior descending and circumflex arteries. The right ITA was used as a free graft in 19 of 45 (42%) patients and the left ITA was used as a free graft in 3 of 35 (7%). No saphenous vein grafts were placed to the left coronary system in any patient. Over half of these patients (24 patients, 53%) also had occlusive disease in the right coronary artery. A saphenous vein graft was placed to the right coronary artery in 22 of 45 (49%) patients. Ventricular function in this patient subset was good (mean LV score 7.1 +/- 2.1). Intra-operative ITA graft flows were 49.7 +/- 29.1 ml/min for grafts to the left anterior descending and 45.5 +/- 31.7 ml/min for circumflex grafts. There were no perioperative deaths. Morbidity included myocardial infarction, stroke and reoperation for bleeding in 1 patient each (2.2%). Low cardiac output occurred in 2 patients (4.4%). No patient had a mediastinal wound infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Nitric oxide inhibits norepinephrine stimulated contraction of human internal thoracic artery and rat aorta.

The effect of nitric oxide (NO) on norepinephrine-induced vascular contraction was evaluated using segments of rat aorta and human internal thoracic artery (ITA) and the NO donor, SNAP. NO levels were measured directly using an amperometric probe. Concentrations of NO greater than 2 nM were required to reduce vascular contraction induced by 100 nM norepinephrine (NE). Exposure of the aortic rings to SNAP prior to, or after NE addition, resulted in a similar attenuation of NE-induced contraction. In contrast, increased relaxation of ITA segments in response to SNAP was observed relative to that of rat aorta and significant development of contractile tone following NE addition was not observed. Evaluation of cytoskeletal actin demonstrated marked loss of F-actin content in smooth muscle cells following NO exposure, suggesting that NO may have direct and indirect effects on contractile tone. These data taken together suggest that vascular responsiveness to contractile agents may be significantly attenuated by prior or subsequent exposure to NO, and mechanisms in addition to vascular relaxation are likely to contribute to this effect.

Animals↗