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PubMedDate not supplied

Cardiac pacing induced flow responses in internal thoracic artery and saphenous vein coronary artery bypass grafts.

The flow reactivity of an internal thoracic artery (ITA) graft and a vein graft for multiple coronary beds in response to different modes of cardiac pacing remains unclear. These experiments were conducted in 14 anesthetized dogs with the ITA or the vein grafted to the circumflex coronary artery, off pump, using a brief local occlusion. The left main coronary artery was occluded, rendering the entire left ventricle totally dependent upon the ITA graft or the vein graft. When the left main coronary artery was occluded and the heart rate was 120 beats per min, graft flow was 93.4 +/- 9.6 ml per min in the ITA, and 96.1 +/- 10.4 ml per min in the vein graft. Atrial pacing to increase heart rates 25% to 150 beats per min increased both the ITA graft flow (110.3 +/- 9.7 ml per min, p < 0.05 versus flow in sinus rhythm) and the vein graft flow (109.8 +/- 7.9 ml per min, p < 0.05 versus flow in sinus rhythm). The increases in flow in both cases were not attributable to changes in perfusion pressure. In contrast, ventricular pacing to the same heart rate decreased systemic pressure slightly, but insignificantly. Despite the slight decrease in perfusion pressure, ventricular pacing increased ITA flow (107.9 +/- 8.4 ml per min, p < 0.05 versus flow in sinus rhythm), but the increase in vein graft flow was not significant compared with flow in sinus rhythm (102.1 +/- 7.3 ml per min, p = ns versus flow in sinus rhythm).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

[Duplex scanning of the internal thoracic artery for coronary artery surgery].

Ultrasonic duplex scanning was used to examine 77 internal thoracic arteries (ITA). The investigated vessels were classified as normal, stenosed (peak systolic velocity was faster than 150 cm/sec and doppler signals showed turbulent pattern), small (diameter measurements were smaller than 1.4 mm and mean flow velocities were slower than 20 cm/sec in distal part of the vessels), and occluded (no flow characteristics could be detected) by the doppler spectrum analysis and the two-dimensional B-mode images. The results of the duplex examination were compared with operative findings and angiograpic findings. Diameter measurements by duplex scanning compared with operative findings showed virtually no differences. One stenosed ITA, a 75% stenosis in the proximal part of the vessel, and two small ITAs were detected by duplex scanning. We performed coronary artery bypass grafting using distal part of the stenosed ITA as a free graft, and used small ITAs as individual bypass grafts. Two normal ITAs were misjudged as small, and one small ITA was misjudged as occluded. All normal ITAs of duplex examination showed normal findings of angiography. Duplex scanning is a reliable, sensitive, and noninvasive technique for the preoperative assessment of the ITA, and is a suitable screening for coronary artery surgery.

Coronary Artery Bypass↗
PubMed2001

Purely internal thoracic artery grafts: outcomes.

BACKGROUND: Most of our patients with coronary artery disease have undergone bypass exclusively with purely internal thoracic artery grafts (PITA). Our goal has been to lengthen the time a patient benefits from coronary bypass operations. The present report describes an 8.5-year study of outcomes including mortality and the need for reintervention in patients who have undergone bypass with PITA. METHODS: We studied 897 patients who underwent PITA with a total of 3,784 internal thoracic artery (ITA) grafts (4.2 grafts per patient). Connecting ITA to ITA along with sequential anastomosis made the procedure possible. RESULTS: Early mortality for the group was 2.3%. Freedom from death was 86% and freedom from reintervention was 94% at 5 years after the operation. CONCLUSIONS: The acceptable early and late mortality and the 94% freedom from reintervention as long as 8.5 years after operation in this group of patients inspire us to continue choosing PITA for patients with three-vessel coronary artery disease.

Adult↗
PubMed2005

Effects of pre-natal and early post-natal undernutrition on adult internal thoracic artery function.

OBJECTIVE: Previous studies in humans and animals have suggested that undernutrition in utero and in early post-natal life may lead to altered vascular function in a number of peripheral arteries. We investigated the effect of pre- and post-natal nutrient restriction on the vascular reactivity of the left internal thoracic artery using a sheep model. METHODS: Welsh mountain ewes were mated and assigned to three dietary groups: (1) 100% of total nutritional requirements (control, n=6); (2) 50% of total nutritional requirements during the first 31 days of gestation (n=6); and (3) 50% nutritional restriction during the first 31 days of gestation, followed by a restriction in the diet of their offspring 12-25 weeks post-natally, designed to produce a 15% reduction in growth trajectory (n=7). The male offspring were sacrificed at 130 weeks; the left internal thoracic artery was mounted onto a wire myograph and the reactivity of the vessel to various agonists measured. RESULTS: The offspring of animals who underwent an early gestation nutrient restriction had a significantly increased basal tone (0.41+/-0.25 vs 6.34+/-1.35, p=0.015) and sensitivity to phenylephrine (log EC(50): -6.23+/-0.04 M vs -5.74+/-0.17 M, p=0.036) as compared with control animals. However, this phenomenon was not seen in animals that underwent both pre- and post-natal nutrient restriction. CONCLUSIONS: Pre-natal undernutrition increases the basal tone and sensitivity of the left internal thoracic artery to phenylephrine. This effect is significantly attenuated by continued undernutrition in early post-natal life. These experiments suggest that in utero and early post-natal undernutrition may be important determinants of graft function in later life.

Animal Nutritional Physiological Phenomena↗
PubMed2006

Late-term regression of stenosis at the kink site in the internal thoracic artery in two cases.

A kink in the internal thoracic artery (ITA) is a rare postoperative complication after coronary artery bypass surgery. The kink can be accompanied by significant stenosis and has been observed after the ITAs are harvested by the skeletonization method. In this report, we present two cases in which early postoperative angiography showed the kink accompanied by significant stenosis, and late angiography revealed regression of stenosis at the kink site. Immediate intervention is not always necessary even when the kink, accompanied by significant stenosis was observed on early postoperative angiography.

Aged↗
PubMed1994

Preoperative evaluation of the right internal thoracic artery for coronary surgery.

In general, the right internal thoracic artery (ITA) is used less frequently as a graft than the left ITA in coronary artery bypass grafting. To determine whether there is an anatomic or hemodynamic rationale for the underuse of the right ITA, noninvasive measurements of right and left ITAs were performed in 171 patients before the bypass procedure. Transthoracic visualization of both vessels was accomplished using a color-flow duplex scanner (5.0-MHz probe) through the third intercostal space. The diameter (in millimeters), peak systolic velocity (in centimeters per second), and end-diastolic velocity (in centimeters per second) were measured in all but 2 patients. The mean right ITA diameter was 2.7 +/- 0.6 mm, the mean peak systolic velocity was 100 +/- 29 cm/s, and the mean end-diastolic velocity was 6 +/- 5 cm/s. Diameter and flow velocity measurements for the right and left ITA were similar in all patients (p = not significant). The measured values for both sites were independent of age and sex, or the presence of hypertension or diabetes mellitus (p = not significant). We conclude that no morphologic or physiologic differences exist between the right and left ITAs. The findings from this study indicate that color-flow duplex ultrasound imaging is a safe and reliable noninvasive technique in the preoperative assessment of the anatomic and functional characteristics of the right ITA before coronary artery bypass grafting.

Adult↗
PubMedDate not supplied

Noninvasive assessment of internal thoracic artery for reoperative coronary artery surgery.

To determine whether previous sternotomy alters internal thoracic artery (ITA) anatomy and flow characteristics, a duplex scanner was used for noninvasive evaluation of the ITA in 59 patients who were scheduled for reoperative coronary artery bypass surgery. The left ITA was insonated through the third intercostal space by use of a duplex scanner (5.0 MHz probe). Measurements of the ITA diameter (mm) and peak systolic velocity (cm/sec) were obtained; ITA flow was calculated from velocity and cross-sectional area. These findings were compared with the values obtained from 105 patients who were scheduled to undergo first-time (primary) coronary artery surgery during the same time period. In the reoperative group, preoperative mean ITA diameter was 2.26 +/- 0.06 mm; this was not significantly different from the primary group's mean ITA diameter of 2.15 +/- 0.04 mm (p = 0.09). Mean peak systolic velocity was 79.9 +/- 2.4 cm/sec and calculated systolic blood flow was 204.6 +/- 13.1 ml/min in the reoperative patients, as compared with 83.3 +/- 2.1 cm/sec and 189.5 +/- 8.6 ml/min in the primary group, respectively. Values were similar in both groups for the peak systolic velocity (p = 0.31) and calculated systolic blood flow (p = 0.32). These results suggest that previous heart surgery or sternotomy does not adversely affect ITA anatomy and flow characteristics. We conclude that ultrasonic imaging is an easily applicable technique for preoperative assessment of ITA in patients who have undergone previous sternotomy.

Aged↗
PubMed2003

Does competitive flow reduce internal thoracic artery graft patency?

BACKGROUND: In coronary arteries with moderate stenosis, competitive flow may lead to internal thoracic artery (ITA) graft occlusion. The goals of this study were to determine if competitive flow reduces ITA patency, and if there is a degree of coronary stenosis below which ITAs should not be used. METHODS: From 1972 to 1999, 50,278 patients underwent primary coronary artery bypass grafting (CABG). Of these, 2,002 had at least one ITA graft and postoperative angiography before coronary reintervention; 2,999 angiograms of 2,121 ITAs were made. Time-related ITA occlusion was modeled using longitudinal analysis to identify its risk factors while accounting for lack of independence introduced by repeated angiography and multiple ITA anastomoses per patient. Proximal coronary stenosis (maximum preoperative stenosis between ITA anastomosis and aorta) was the surrogate for competitive flow. RESULTS: Unadjusted ITA patency was 93%, 89%, 90%, and 92% at 1, 5, 10, and 15 years after CABG. Risk factors associated with ITA occlusion were lesser degree of proximal coronary stenosis (p < 0.0001); longer time from CABG in grafts to non-left anterior descending coronary arteries (p < 0.0001); female sex (p = 0.0003); later date of CABG (p = 0.01); right ITA (p < 0.0001); and smoking (p < 0.0001). In all arteries, as preoperative proximal coronary stenosis decreased, ITA patency declined; however, at no degree of stenosis was there a sharp decline. CONCLUSIONS: Internal thoracic artery patency decreases as coronary competitive flow increases. However, the nature of this relationship indicates ITAs should not be abandoned at moderate grades of stenosis.

Aged↗
PubMed1997

[Assessment of left internal thoracic artery anastomosis with left anterior descending coronary artery by Doppler echocardiography].

PURPOSE: To study the value of Doppler echocardiography as a tool for the evaluation of left internal thoracic artery graft (LITAG) patency in patients who underwent coronary revascularization using minimally invasive bypass surgery without extracorporeal circulation. METHODS: The first 12 consecutive patients were studied after coronary artery bypass surgery using a 5 MHz Doppler transducer. Doppler signals for the systolic and diastolic flow velocities were preferably obtained in the second intercostal space. All patients underwent coronary angiography while hospitalized. RESULTS: The exam was feasible in 93% of patients. Doppler flow pattern was predominantly diastolic (pattern A) in patients with patent anastomoses (6/7). In patients with occluded anastomoses (4/4) Doppler flow pattern was predominantly systolic (pattern B) (p = 0.003). CONCLUSION: Internal thoracic artery flow pattern as measured by Doppler echocardiography after minimally invasive coronary artery bypass graft surgery is an accurate method for identifying LITAG patency.

Adult↗
PubMed1993

[Mechanical dilation of the internal thoracic artery graft by using balloon catheter].

We evaluated the free flow of the internal thoracic artery grafts (ITA) which were dilated with a balloon catheter. Further, we examined the postoperative angiographic findings and histology of the ITAs by scanning electron microscopy. In 25 patients with internal thoracic artery grafting, the artery was dilated with a balloon catheter (Fogarty IMAG kit) that was withdrawn at tensions of less than 30 gm. The mean free flow rate of the left ITAs (LITAs) increased from 64.2 ml/min to 101.9 ml/min by injection of papaverine to ITAs (p < 0.05). The mean free flow rate of the balloon dilated LITAs were 160.8 ml/min which was significantly higher when compared with that of control and papaverine (p < 0.01, p < 0.01). The mean free flow rate of the balloon dilated right ITAs (RITAs) showed 183.2 ml/min, it was significantly higher (p < 0.01, p < 0.05) compared with that of control (78.4 ml/min) and papaverine (129.2 ml/min). Irregularity was documented in 16% of the ITAs in spite of the great patency rate (100%) from the postoperative angiogram. Using scanning electron microscopy, endothelial cell borders were well demarcated in the proximal portion of the dilated ITA. However, the distal portion of the endothelium displayed gradual destruction. Although mechanical dilation of the ITA graft by balloon calibration is very effective in increasing the free flow rate of ITA, we should be prepared for the intimal damage of the ITA graft.

Adult↗
PubMed2003

Estrogen receptor expression and synthesis in the human internal thoracic artery.

The inhibition of vascular smooth muscle cell proliferation is mediated through two intracellular estrogen receptors (ERs), ER-alpha and ER-beta. Deletion variants of ER-alpha have been decribed for cultures of smooth muscle cells. The internal thoracic artery is frequently used as coronary artery bypass graft, yet neither has it been studied for the expression of ER subtypes nor for the synthesis of the ERs in morphologically hetergeneous smooth muscle cells. Using nested RT-PCR, we have demonstrated the mRNA for ER-alpha splicing variants in intact human internal thoracic arteries. The 7A deletion variant occurred in 8 out of 12 cases, the full-length transcript in three cases. The full-length transcript was always found for the ER-beta. Immunolocalization revealed ER-positive nuclei in the desmin-positive subset of smooth muscle cells, but not in cytokeratin (CK)-positive cells of the thickened intima. Morphological evidence is presented suggesting that ER synthesis is high in the tunica media when cell proliferation of smooth muscle cells is increased. We conclude that, in internal thoracic arteries, the 7A deletion variant of ER-a occurs in 75%, whereas the full-length transcript is found in all cases. The significance remains unclear.

Alternative Splicing↗
PubMed1998

Long-term patency rate of right internal thoracic artery bypass via the transverse sinus.

BACKGROUND: Although concern regarding patency and possible compromise of graft blood flow by routing the right internal thoracic artery (RITA) through the transverse sinus has been raised, little is known about long-term patency. METHODS AND RESULTS: To evaluate long-term patency of in situ RITA bypass via the transverse sinus, our first 115 patients (94 men, 21 women; mean age, 62.5 years; range, 13 to 77 years) who were alive in 1998 were enrolled for angiographic study. Only good-caliber grafts with no occlusion, string sign, or significant stenosis were considered patent. Early postoperative angiography had been performed 2 to 3 weeks after surgery in 114 patients. The early patency rates were 97.1% for RITA and 95.4% for left internal thoracic artery (LITA) grafts. Of 109 long-term survivors, 73 (67.0%) consented to have late angiographic restudy at a mean of 59 months (range, 9 to 93 months); 89.9% of RITA and 92.3% of LITA grafts were patent. Cumulative patency rates (actuarial curves) at 6 years were 89.3% (95% CI, 85% to 94%) for RITA and 94.5% (95% CI, 92% to 97%) for LITA, the differences not reaching statistical significance (multivariate Cox analysis). CONCLUSIONS: Our study demonstrated good long-term patency of in situ RITA bypass grafting via the transverse sinus for revascularization of the circumflex and diagonal arteries and supports its continued use.

Adolescent↗
PubMedDate not supplied

Bovine internal thoracic artery graft. Successful use at urgent coronary bypass surgery.

Bovine internal thoracic artery grafts (Bioflow) were successfully utilized in two patients for emergency coronary artery bypass grafting (CABG). One patient was an 80-year-old man with severe varicose veins and a calcified ascending aorta. Heart failure occurred after triple CABG with bilateral internal thoracic and gastroepiploic arteries. The addition of a Bioflow graft to the circumflex artery restored good cardiac function. The second case was a 54-year-old man whose patent old saphenous vein graft was accidentally injured at reoperation. Emergency use of the Bioflow to bypass the right coronary artery in combination with the right gastroepiploic artery graft to the anterior descending artery resulted in an excellent outcome. The two Bioflow grafts were patent at the 20th and 10th postoperative days, respectively. These cases strongly suggest the efficacy of Bioflow during emergency situations in CABG.

Aged↗
PubMedDate not supplied

Internal thoracic arterial grafts evaluation by multislice CT scan: a preliminary study.

BACKGROUND AND AIM: The internal thoracic artery (ITA) has a better long-term patency than saphenous veins, and anastomosis between ITA and the left anterior descending artery (LAD) represents the "gold-standard" of surgical myocardial revascularization. The aim of this study is to evaluate the multidetector multislice CT Scan (MCTS) as a means of postoperative evaluation of ITA coronary artery bypass grafts. METHODS: Twenty-eight patients having been operated on for coronary artery bypass with ITA during a 6-months period, benefited, 7 days after surgery, from a patency and anastomotic site control of ITA with a MCTS associated with cardiac gating (Light Speed, General Electric, USA). RESULTS: Internal thoracic artery bypasses are visualized perfectly on all their courses, with possibility of 3D reconstructions, showing the relationship between cardiac cavities and the arterial bypasses. The anastomotic site on the LAD was, in selected cases, perfectly visualized. Sequential bypasses with left ITA are well visualized as well as T or Y right-to-left ITA grafts. However, surgical clips create some image artefacts. CONCLUSIONS: The postoperative control of ITAs are possible by MCTS with a satisfactory resolution. This makes it possible to check the patency of ITAs, their course on the heart surface, and the location and quality of anastomosis with a noninvasive reproductive method.

Anastomosis, Surgical↗
PubMed1994

Transient reversal of blood flow in an internal thoracic artery to coronary artery graft during syncope.

Transcutaneous duplex ultrasound can be used to image and quantify blood flow in the proximal part of the internal thoracic artery to coronary artery bypass grafts. In addition to providing information about graft patency and blood flow for follow-up purposes, the technique also provides an opportunity to study the physiology and pharmacology of the coronary circulation. In this paper we describe and attempt to interpret an unusual pattern of internal thoracic artery graft blood flow observed during inadvertent nitrate-induced syncope.

Coronary Artery Bypass↗
PubMed2004

Assessment of a caudal external thoracic artery axial pattern flap for treatment of sternal cutaneous wounds in birds.

OBJECTIVE: To assess the use of a caudal external thoracic artery axial pattern flap to treat sternal cutaneous wounds in birds. ANIMALS: 16 adult Japanese quail. PROCEDURE: A cutaneous defect in the region of the mid-sternum was surgically created in all quail. In 6 quail (group I), an axial pattern flap was created from the skin of the lateral aspect of the thorax and advanced over the sternal defect. In 8 quail (group II), a flap was similarly created and advanced but the flap vasculature was ligated. All quail were euthanatized at 14 days after surgery and had necropsies performed. Sections of the flap and the surrounding tissue were examined histologically to assess flap viability. RESULTS: All axial pattern flaps in group-I quail had 100% survival. In group II, mean percentage area of flap survival was 62.5%; mean area of necrosis and dermal fibrosis of flaps were significantly greater than that detected in group I. In flaps of group-II quail, neovascularization in the deep dermis and profound necrosis of the vascular plexus in the superficial dermis were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the caudal external thoracic artery axial pattern flap could be used successfully in the treatment of surgically created sternal cutaneous defects in quail with no signs of tissue necrosis or adverse effects overall. Use of this technique to treat self-mutilation syndromes or application after surgical debulking of tumors or other masses might be beneficial in many avian species.

Animals↗
PubMed2002

Totally endoscopic bilateral internal thoracic artery bypass grafting in a young diabetic patient.

BACKGROUND: The introduction of robotics into cardiosurgical practice in 1998 has enabled totally endoscopic closed chest procedures. Totally endoscopic grafting of the LAD (TECAB) is no longer an experimental procedure. CASE REPORT: We report on a case with totally endoscopic bilateral internal thoracic artery bypass grafting to the left anterior descending and right coronary artery in a 36-year-old obese female diabetic patient using the daVinci surgical system. The patient, suffering from juvenile diabetes for 26 years, presented with stable angina (CCS class II). A coronary angiogram revealed 2-vessel disease with a long complex proximal lesion of the left anterior descending artery (LAD) (90%) and 80% stenosis of the proximal right coronary artery (RCA). Due to the condition of the proximal LAD (high risk PTCA with rather poor prognosis), the patient was referred for minimally invasive operative revascularisation of the LAD and the RCA. After informed consent was obtained the patient underwent totally endoscopic double internal thoracic artery bypass revascularisation on the arrested heart using computer-enhanced telemanipulation technology. RESULTS: The feasibility and safety of successful closed chest, totally endoscopic double coronary bypass grafting with two internal thoracic arteries is demonstrated in this case. Preservation of a stable chest cavity and reduced risk for wound healing complications in diabetics with an excellent cosmetic result are the obvious advantages of the techniques described.

Adult↗