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.     

Bovine internal mammary artery as a conduit for coronary revascularization: long-term results

Preterm infants may become apneic during immediate postoperative period. We studied prospectively postoperative apneic attack in 167 preterm infants after inguinal herniorrhaphy with nitrous oxide-halothane anesthesia. Their mean gestational age was 30 +/- 3 weeks. The mean postnatal age at operation was 14 weeks. The post-conceptual age varied between 36 and 56 weeks. The mean birth weight was 1351 +/- 395 kg. Although many of them had a risk factor of postoperative apneic attack, i.e.a young post-conceptual age (less than 41 weeks), a light weight at operation (below 3000g), only one infant who had received emergency operation had an episode of apneic attack up to 2 postoperative days. For preventing postoperative apneic attack in preterm infants after inguinal hernia, we recommend the use of halothane anesthesia and the attention until a complete awakening.     

Use of an internal mammary artery graft in the revascularization of the myocardium. A ten-year follow up study

Between September 1986 and August 1996, 233 patients (187 males, 46 females) ranging in age from 32 to 81 (mean 54.7) years received at least one internal mammary artery (IMA) graft for coronary artery bypass procedures. The mean left ventricular ejection fraction was 55.1% (range, 17 to 75%). An average of 3.1 distal anastomoses per patient was constructed. Hospital mortality was 2.1%. Perioperative myocardial infraction was seen in 2.1%. The mean follow-up of hospital survivors was 39.2 (range, 4 to 123) months. Ten-year actuarial survival for patients discharged from the hospital was 96%. Recurrence of angina occurred in 18 patients and reoperation or PTCA was performed in 3 patients in the late follow-up period. These results support the continuing use of IMA grafts for myocardial revascularization.     

Experience with internal mammary artery grafts in 298 patients

The internal mammary artery (IMA) was used as a graft in 298 patients undergoing coronary bypass procedures. Two patients died during the operative period and 2 others died one year later. Most of the survivors are free of angina. Of the IMAs restudied 9 to 24 months postoperatively, 95% were patent. This group included nearly all the patients having angina after operation. There are some situations in which the IMA may have inadequate flow in comparison to the vein graft. These results suggest the IMA is an excellent graft in most coronary bypass procedures.     

Role of direct revascularization of the internal iliac artery during aortoiliac surgery

BACKGROUND: In the event of hemorrhage and blood loss, platelets play a vital role in the coagulation process. However, there are currently no acceptable protocols for long-term storage of platelets. As a first step toward testing the efficacy of stored platelets or platelet substitutes in vivo, a flow cytometric technique was developed to detect human platelets in rabbit blood. STUDY DESIGN AND METHODS: Human platelets were transfused to rabbits whose reticuloendothelial system was inhibited by the administration of ethyl palmitate. Because human and rabbit platelets display surface molecules with different epitopes, human platelets were selectively labeled with antibodies specific for glycoprotein IX (CD42a). As this antibody does not label rabbit platelets, it allows discrimination of human from rabbit platelets in samples of rabbit blood containing both types of platelets. RESULTS: Survival of human platelets in rabbits was monitored by flow cytometry and fluorescence microscopy in blood drawn at various times after the platelet transfusion. Fresh human platelets transfused to untreated control rabbits (n = 3) were removed from circulation within 10 minutes of the completion of the transfusion. Fresh platelets (1 day old) transfused to rabbits treated with ethyl palmitate (n = 5) survived for 24 hours with an average half-life of 8.6 hours. In contrast, 8-day-old platelets were cleared from the circulation sooner with an average half-life of 2.9 hours (n = 4). CONCLUSION: This report describes a rapid and efficient method of assessing the survival of human platelets in a rabbit model using flow cytometry. This technique will enable the monitoring in rabbits of human platelets prepared by various preservation protocols.     

Minimally invasive bilateral internal mammary artery bypass grafting

A 34-year-old HIV-positive black man with pulmonary tuberculosis developed progressive widening of the mediastinum. Evaluation by CT and two-dimensional echocardiography demonstrated a large saccular aneurysm of the ascending aorta. This was repaired with a 26-mm aortic homograft using deep hypothermic circulatory arrest. The microbiology of the aneurysm contents showed this to be a tuberculous pseudoaneurysm.     

The use of bilateral mammary artery in myocardial revascularization. The risk factors emergent from a multivariate analysis conducted on 474 patients

Between January 1989 and March 1997, 175 patients with traumatic shoulder dislocation were treated by conservative means (median age 41 years, 39 F, 136 M). In 78 patients (17 F, 61 M) a clinical and radiological follow up (median 50 months, range 6-106) could be obtained. Additionally, a diagnostic ultrasound was carried out in all patients. The recurrence rate in the group younger than 30 years (G < 30; n = 35) was 86%; in the group older than 30 years (G > 30; n = 43) it was 21% (P < 0.05). Persisting neurological deficits were found in 6 patients (8%). According to the Rowe score, 16 patients (46%) of the G < 30 achieved excellent or good results, in the G > 30, 29 patients (67%). In 17% of cases, a glenohumeral arthrosis was diagnosed be radiological means. 18% had radiological signs of a previous fracture of the greater tuberosity. Hill-Sachs lesions were identified in 19% of cases. Rotator cuff tears were diagnosed in 9% by ultrasound. No relationship between the duration of immobilization and the recurrence rate was found (P = 0.95). The recurrence rate following primary shoulder dislocation depends primarily on the patients' age.     

Blood flow in the internal mammary artery after the administration of papaverine during coronary artery bypass grafting

Vaccination against Newcastle disease with the thermotolerant LaSota/A300 and V4/276 coated-millet vaccines was tried in Ouagadougou, Burkina Faso, by feeding 298 European broiler chickens exhibiting maternal antibodies. Opportunistic infections, such as colibacteriosis, decimated 70-81% of the three vaccinated groups and 24% of control, before being eradicated by antibiotic therapy. The surviving chickens were challenged two months after vaccination with the Hertz 33/56 virus strain. This resulted in 100% deaths in the control group, 78% in birds vaccinated with the V4/276, 7% in birds fed with LaSota/A300, and in no death in the group given both vaccines at one week interval. These last two groups also exhibited high titres of 1HA antibodies before the challenge. The lyophilized LaSota/A300 and V4/276 vaccines kept high viral titres after 8-34 days' ambient temperature exposure during the cool season in Ouagadougou.     

Maximal utilization of the left internal mammary artery for coronary bypass grafting

A technique is described for using the internal mammary artery to bypass the left anterior descending coronary artery and another adjacent coronary artery even when the alignment of the two vessels is not favorable for a conventional sequential graft. The distal end of the mammary artery is amputated and used to construct a Y graft to the anterior descending artery and to the secondary target vessel.     

The effects of levcromakalim and pinacidil on the human internal mammary artery

The present study was undertaken to examine the effects of pinacidil and levcromakalim, two potassium, channel openers, on human internal mammary artery (HIMA) obtained from patients undergoing coronary artery bypass surgery, and to clarify the contribution of different K+ channel subtypes in pinacidil and levcromakalim action in this blood vessel. Pinacidil and levcromakalim induced a concentration-dependent relaxation of the precontracted arterial segments (pEC50 = 5.77 +/- 0.05 and 6.89 +/- 0.03, respectively), 4-Aminopyridine (3 mM), a non-selective blocker of K+ channels, induced significant shifts to the right of the concentration-response curves for pinacidil and levcromakalim. Tetraethylammonium (6 mM), charybdotoxin (0.4 microM) and apamin (0.1 microM), blockers of Ca(2+)-sensitive K+ channels, had no effect on the pinacidil- and levcromakalim-evoked relaxation. Glibenclamide (0.1-10 microM), a selective blocker of adenosine triphosphate (ATP)-sensitive K+ channels, competitively antagonized the response to levcromakalim (pKB = 7.92 +/- 0.07). In contrast, glibenclamide, in significantly higher concentrations (3-30 microM), non-competitively antagonized the response to pinacidil. High concentrations of pinacidil (> 10 microM) relaxed arterial rings bathed by a medium containing 100 mM K+ with maximum response 83 +/- 6%. Under the same conditions, the maximum levcromakalim-induced relaxation on HIMA was almost abolished (15 +/- 2%). It is concluded that pinacidil and levcromakalim do not relax the HIMA through the same subtype of K+ channel. ATP-sensitive K+ channels are probably involved in levcromakalim- but not in a pinacidil-induced relaxation in the HIMA. In addition, in pinacidil-induced relaxation of the HIMA, K+ channel-independent mechanisms seem to be involved.     

Intercostal lung hernia subsequent to harvesting of the left internal mammary artery

We report a case of an intercostal lung hernia developing subsequent to harvesting of the left internal mammary artery. Intercostal lung hernia is extremely rare, with most cases reported after blunt thoracic trauma. In the absence of symptoms, this was treated conservatively.     

Why the internal mammary artery is an ideal graft for myocardial revascularisation? (an experimental model with omentoplasty)

Ten dogs underwent coronary artery bypass grafting through a right thoracotomy. Free internal mammary artery grafts (IMA) was used for aortocoronary bypass to right coronary artery (RCA) without temporary cardiopulmonary bypass. In upper median laparotomy approach, mobilization and lengthening of the omentum was performed through the retrosternal part of the diaphragm. An epiploic muff was effectuated surrounding the IMA graft. After three months the animals were sacrificed and the grafts folded by omentum were used for microscopical study. The histological evaluation has shown that the omentum has formed a new adventitia around the graft. In the new-formed adventitia, newly formed vessels can be found and these are grouped around the adventitia-media border zone, very rarely penetrating into the external layer of the media. This graft-omentoplasty offer a good experimental model which facilitates to investigate in vivo the blood supply needed by free IMA grafts through the adventitia in experimental conditions. The biological mechanism of angiogenesis in graft wall can be investigate as well.     

The internal mammary artery malperfusion syndrome: late angiographic verification

BACKGROUND: Here we report our experience with the incidence and the surgical treatment of the internal mammary artery (IMA) malperfusion syndrome, evaluate the predictive role of previously described risk factors for the syndrome, and assess the late patency of IMA grafts in patients in whom an IMA malperfusion syndrome was diagnosed and treated by additional saphenous vein grafting of the left anterior descending coronary artery. METHODS: From June 1992 to November 1995, 969 IMAs were anastomosed to the left anterior descending coronary artery system. In 11 patients, IMA malperfusion syndrome was diagnosed and treated by additional saphenous vein grafting of the LAD. There were 8 men and 3 women with a mean age of 58.9 years. The angiographic and clinical data for each patient were reviewed, and all but 1 surviving patient underwent late angiographic control (mean follow-up, 18 months; range, 4 to 46 months). RESULTS: One patient died in the hospital. No previously described risk factor was strongly associated with the occurrence of IMA malperfusion syndrome. Late angiography revealed a malfunctioning IMA graft in 7 of the 9 patients. A string sign was observed in 1 patient and a normally functioning IMA anastomosed to a diagonal branch not connected to the LAD, in another. In no patient was a widely patent and normally functioning IMA graft observed. CONCLUSIONS: In our series, a high proportion of IMA grafts were found to be malfunctioning at late angiography. This observation, in contrast to previous reports, suggests that IMA malperfusion syndrome can often be attributable to technical problems in harvesting the IMA or in performing the IMA anastomosis. Functional IMA insufficiency seems to play only a marginal role in determining the IMA malperfusion syndrome.     

Noninvasive hemodynamic monitoring of critical patients in the emergency department

OBJECTIVE: To evaluate the feasibility of multicomponent noninvasive hemodynamic monitoring in critical emergency patients and to compare this technique with simultaneous invasive monitoring by the pulmonary artery thermodilution catheter. METHODS: A prospective observational study was done comparing invasive monitoring and noninvasive monitoring in 60 critically ill or injured patients who required hemodynamic monitoring shortly after entering the ED of a university-affiliated country hospital. Cardiac output (CO) values measured by the standard thermo-dilution pulmonary artery catheter technique were compared with simultaneously obtained measurements using a noninvasive bioimpedance method. Concurrent measurements were made of pulse oximetry to screen pulmonary function and transcutaneous oximetry to assess tissue perfusion. RESULTS: The impedance CO values closely approximated those for the thermodilution method; r 0.81, p < 0.001. Significant circulatory abnormalities, including hypotension, reduced cardiac index, arterial hemoglobin desaturation, tissue hypoxia, reduced O2 delivery, and consumption, were found in 54 of the 60 (90%) patients. The cardiac index decreased in 44% of the patients, the transcutaneous O2 decreased in 39%, and the O2 saturation by pulse oximetry fell in 22% during the observation period in the ED (commonly lasting 2-8 hours). CONCLUSIONS: Noninvasive monitoring can provide hemodynamic and perfusion information previously available only by invasive thermodilution catheters. Such noninvasive monitoring can display continuous on-line real-time data, allowing immediate recognition of circulatory abnormalities and providing a means to titrate therapy to appropriate therapeutic goals.     

The internal mammary artery 'string phenomenon'. Analysis of 10 cases

The internal mammary artery (IMA) string sign has been described as a narrowing of IMA grafts in the late course after coronary artery bypass grafting. It has been assumed that this phenomenon was due to competitive flow in grafts connected to only mildly stenosed coronary arteries. We analyzed 10 cases of IMA string sign operated on between March 1988 and June 1991. Bilateral IMA was used in six cases and unilateral IMA in four. The mean interval between operation and reangiography was 14 +/- 11 months. String sign of the whole length of the IMA was detected in nine cases, and of the distal part between two sequential anastomoses in one. In all cases, the stenosis of the vessel bypassed with the narrowed graft proved to be only mild (50% or less) at reangiography. In all six cases with bilateral IMA grafts, the contralateral IMA was widely patent. These were all connected to highly stenosed or occluded coronary arteries. With respect to this observation, there is a high index of suspicion that the string phenomenon occurs due to competitive flow in only mildly stenosed coronary arteries. We decided, for our strategy in coronary artery surgery, still to aim at complete revascularization using IMAs as much as possible, but to avoid connecting IMA grafts to only mildly or moderately stenosed coronary arteries.     

Breast infarction after internal mammary artery harvest in a patient with calciphylaxis

The use of the internal mammary artery during coronary artery bypass grafting is commonplace. Complications associated with the harvest of the internal mammary artery have predominantly been wound related. These range from skin dehiscence to complete avascular necrosis of the sternum. This report documents complete ischemic necrosis of a breast in a patient with end-stage renal disease and a history of calciphylaxis, after the harvest of an internal mammary artery.     

Elective stenting of a de novo ostial lesion of the right internal mammary artery

Left single lung transplantation was performed under perioperative extracorporeal membrane oxygenation (ECMO) support for a patient of primary pulmonary hypertension. Continuous ECMO in this patient for one day after the transplantation decreased the pulmonary blood flow and probably served to minimize the potential complication of reperfusion edema of the graft. During this period, the ECMO was gradually weaned so that the grafted lung could adapt itself to the gradually increased blood flow through it. The patient was extubated without difficulty 2 days alter the removal of ECMO and made a smooth recovery.