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Query: UMLS:C0729233 (Thoracic)
 6,478 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An electron microscopic study of heart muscle tissue exposed to six hours ischemia and prepared according to the low denaturation embedding technique revealed a structural modification confined to the mitochondrial cristae. The modification consisted of a removal of Krebs cycle enzymes from the cristae. Reperfusion of the ischemic tissue after four hours ischemia led to extensive breakdown of the mitochondrial structure and contractility could not be restored. However, when after six hours ischemia the ischemic tissue was reperfused with blood, the composition of which had been modified to stimulate mitochondrial function, no additional structural changes were observed and contractility was restored. The structural damage caused by reperfusion with non modified blood is explained by a loss of control of plasma membrane permeability caused by impaired ATP production which makes the ionic composition of the cytosol approach that of blood plasma, stopping oxidative phosphorylation. A treatment to restore heart muscle function after long periods of ischemia and after heart transplantation is proposed. The structural damage revealed that the Krebs cycle and the respiratory chain enzymes are associated according to a regular periodic pattern and that the enzyme molecules are closely aggregated three-dimensionally. Earlier electron microscopic studies revealing massive structural deterioration of heart muscle cells already after 45 to 60 minutes ischemia leading to the conclusion that the cells are irreversibly damaged, is based on fixation artifacts caused by osmium fixation. This study has been carried out in collaboration with the research team of Gerald D. Buckberg at the Thoracic Surgery Division at University of California at Los Angeles.
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PMID:Information and misinformation regarding ischemia of heart muscle tissue. The cause of cell death during blood reperfusion and reactivation of heart muscle tissue after prolonged ischemia. 129 75

Paraplegia from spinal cord ischemia during thoracoabdominal aneurysm repair remains an unpredictable and unpreventable complication. In an effort to prevent spinal cord ischemia during aortic cross-clamping, preoperative angiographic localization of the blood supply to the spinal cord was performed in dogs. Sixteen animals underwent 60 minutes of thoracoabdominal aortic cross-clamping either without (control, n = 8) or with (shunted, n = 8) a selective shunt. Shunting was performed from the aortic arch to that isolated aortic segment angiographically shown to supply the thoracolumbar anterior spinal artery. Spinal cord blood flow was measured with microspheres just prior to cross-clamping, at 5 and 60 minutes after cross-clamping and at 5 minutes after restoration of aortic blood flow. Functional neurologic outcome was evaluated in animals at 24 hours postoperatively. Shunting did not decrease spinal cord injury. Seven of the 8 animals in the control group and 7 of the 8 in the shunted group developed paraplegia or paraparesis. Thoracic, but not lumbar spinal cord blood flow, was significantly increased in shunted animals. Spinal cord blood supply in dogs may be more segmental than previously believed. Technical problems in angiographic localization, spinal artery spasm, loss of spinal cord autoregulation or poor collateral circulation from the distal thoracic to the lumbar cord may also account for these results. Although shunting to aortic segments supplying the anterior spinal artery during thoracoabdominal aortic clamping may be attractive in humans, no benefit could be shown in this experimental model.
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PMID:Failure of selective shunting to intercostal arteries to prevent spinal cord ischemia during experimental thoracoabdominal aortic occlusion. 129 34

Patients scheduled for vascular surgery are considered at risk for perioperative cardiac complications. Choice of anesthetic in such patients is guided by a desire not to adversely affect myocardial function. On the basis of data from laboratory studies, thoracic epidural anesthesia (TEA) has been advocated to prevent myocardial ischemia. The aim of this study was to assess whether TEA combined with general anesthesia has any effect on segmental wall motion (SWM) monitored by transesophageal echocardiography in these patients. Patients received alfentanil, midazolam, vecuronium, and 50% N2O in oxygen, and ventilation was controlled after orotracheal intubation; 12.5 mL of 2% lidocaine HCl was injected through an epidural catheter placed at T6-7 or T7-8. Hemodynamic measurements and transesophageal echocardiographic recordings were obtained before and 10, 20, 30, 40, and 60 min after lidocaine injection. Segmental wall motion was graded a posteriori by two independent experts on a predetermined scale (from 1 = normal to 5 = dyskinesia). A decrease greater than or equal to 2 grades was considered an SWM abnormality indicative of ischemia. Thoracic epidural anesthesia induced a decrease in systemic arterial blood pressure, heart rate, and cardiac index. The SWM score decreased slightly from 1.34 +/- 0.68 to 1.27 +/- 0.64 (mean +/- SD) (at 10 and 20 min, respectively) (P less than 0.05). Patients were a posteriori analyzed according to whether they had documented coronary artery disease or not. The SWM score before TEA was significantly higher in patients with documented coronary artery disease (1.51 +/- 0.88 vs 1.17 +/- 0.51, respectively; P less than 0.05) and did not change significantly after TEA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of thoracic epidural anesthesia combined with general anesthesia on segmental wall motion assessed by transesophageal echocardiography. 151 Feb 52

Over a 40 year period (1950-1990) only 73 patients were treated surgically for brachiocephalic aneurysms. An operation was performed for 38 subclavian, 25 extracranial carotid, six innominate, three aberrant right subclavian, and one vertebral artery aneurysm. Twenty-three other associated aneurysms occurred in 14 patients. Five patients had an additional untreated brachiocephalic aneurysm, and nine patients had 18 aneurysms located in different anatomic regions. There were 40 men and 33 women with a mean age of 50.5 years (range 16 to 82 years). Forty patients (54.8%) presented with potentially life- or limb-threatening signs or symptoms, including stroke or transient ischemic attacks (31.5%), upper extremity ischemia (19.2%), and rupture (4.1%). Atherosclerosis was most common in innominate aneurysms (66.7%) but also occurred in subclavian (34.1%) and carotid aneurysms (12.0%). Thoracic outlet compression was a common etiology for subclavian aneurysms while trauma or spontaneous dissection was more frequent for carotid aneurysms. Six deaths (8.2%) occurred within 30 days of operation: two from rupture, three in association with concomitant cardiovascular operations, and one from emergency carotid ligation. There were no deaths with elective isolated surgical repair. Overall five and 10 year survival in patients with brachiocephalic aneurysms was 80.8% and 61.4%, respectively. The majority of brachiocephalic aneurysms present with life- or limb-threatening complications and are associated with a high mortality for emergency or concomitant repair. Early elective isolated surgical repair remains the optimal therapy.
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PMID:Brachiocephalic aneurysm: the case for early recognition and repair. 201 82

A 63-year-old man of thoracoabdominal aortic aneurysm was transferred to our department. Thoracic and abdominal enhanced CT scan revealed a Crawford's type I A thoracoabdominal aortic aneurysm ruptured into the right extrapleural and retroperitoneal spaces. Without any more additional examination, graft replacement and reconstruction of a lower intercostal artery were performed with an aid of femoro-femoral bypass. Although the postoperative course was complicated by hypertension, hypoventilation and liver dysfunction, the patient recovered from the operation and 10 months later he is leading an almost normal life. Since emergency operation of thoracoabdominal aneurysm is the most courageous challenge because of the difficulties of exposure and visceral organ protection against ischemic, there have been only nine cases with successful surgery in Japan. Now we actively reconstruct lower intercostal and lumbar arteries to prevent spinal cord ischemia without ESCP monitoring in emergency cases.
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PMID:[A case of thoracoabdominal aortic aneurysm ruptured into the right extrapleural cavity]. 225 Apr 43

A total of 106 lesions due to vascular injuries (noniatrogenic) to limbs were treated in 81 patients at the CHR, Rennes (Cardiovascular and Thoracic Unit) between 1970 and 1983. Analysis of data allowed a profile of arterial lesions (type and location) to be retraced, and demonstrated the high frequency of associated lesions, these varying in distribution according to whether the upper limbs (major seriousness of neurologic sequelae) or lower limbs (very high incidence of osteoarticular lesions) were involved. Among the "immutable" severity factors (related to the injury) emphasis has to be placed on "contending or crush injuries", widely displaced lesions, extensive arterial dilacerations (middle segments of limbs) and multiple vascular lesions. This study focused attention mainly on the tactical and technical factors allowing improvement in the always reserved prognosis of these lesions. Firstly, by maximum reduction in the duration of ischemia by early diagnosis (to avoid referral to a "second hand") and by judicious indication for angiography (conducted preferably in the operation room and if necessary repeated after vascular repair surgery). Secondly, by repair of lesions in conformity with well established rules and principles: bone stabilization initially, formal venous repair surgery for large venous trunks, preferably "conservative" surgery of arterial vessels to ensure a perfect result initially (any recovery operation results in a very high incidence of failures).
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PMID:[Vascular injuries of the limbs. Evaluation of 106 lesions in 76 patients]. 370 Apr 97

Thoracic aortic dissection is an extremely serious vascular accident which must be treated immediately. While ascending aortic dissection requires surgery as soon as possible, descending aortic dissection is only treated surgically when complications such as aortic ectasia, hemorrhage or ischemia occur. Late complications most often lead either to the patient's death or to reoperation. Late death occurs in 4-6% patients/year and about 3% patients/year undergo late reoperation. In our own experience these figures amount to 2 and 0.8% respectively.
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PMID:[Long-term treatment of patients with dissection of the thoracic aorta]. 827 80

A 71-year-old woman had an abdominal aortic disruption as a belted passenger in a motor vehicle accident. The diagnosis was unexpected, and the patient died during surgery. There have been 54 patients operated with this diagnosis since 1953; our patient was the fifty-fifth. This is an unusual injury, because the aorta is well protected in this position. Thoracic aortic injuries are much more common (20 times) than abdominal injuries. The causes are motor vehicle accidents, blows to the abdomen, explosions, and falls. Obstructing lesions such as thrombosis and intimal dissection are the more common presentation. False aneurysms occur occasionally. Free rupture has a very high and immediate mortality rate, and few patients arrive at the hospital alive. Diagnosis can be clinical, based on distal ischemia and neurologic abnormalities, or made with Doppler scanning, ultrasonography, computed tomography, or arteriography. Two thirds present acutely and one third subsequently months or even years after the original injury. Treatment consists of flap suture, thrombectomy, bypass grafting in more extensive injury, or extra-anatomic bypass in the face of severe contamination. Recently, endoluminal stenting has successfully been used, avoiding an abdominal operation completely.
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PMID:Blunt disruption of the abdominal aorta: report of a case and review of the literature. 915 23

We have previously reported that atrial trabeculae from patients taking oral sulfonylurea hypoglycemic agents cannot be preconditioned by transient ischemia, which may, in part, explain the increased cardiovascular mortality historically associated with the use of these agents (J. C. Cleveland et al., 1997, Circulation 96, 29-32). Recently, we reported that clinically accessible and acceptable exogenous Ca(2+) pretreatment protects human atrial trabeculae from subsequent ischemia (B. S. Cain et al., 1998, Ann. Thoracic Surg. 65, 1065-1070). It remains unknown whether this preconditioning strategy could confer protection to trabeculae from patients taking oral sulfonylurea drugs. We therefore hypothesized that exogenous Ca(2+) confers ischemic protection to trabeculae from patients taking oral sulfonylureas. Human atrial trabeculae were suspended in organ baths and field stimulated at 1 Hz, and force development was recorded. Following 90 min equilibration, trabeculae from patients taking oral sulfonylurea agents (n = 6 patients) were subjected to ischemia/reperfusion (I/R; 45/120 min) with or without Ca(2+) (1 mM increase x 5 min) 10 min prior to I/R. I/R decreased postischemic human myocardial contractility in trabeculae from patients on oral hypoglycemics to 15.3 +/- 2.0% baseline developed force (%BDF). Ca(2+) pretreatment increased postischemic human myocardial developed force to 35.3 +/- 2.9 %BDF in these patients (P < 0.05 vs I/R, ANOVA and Bonferroni/Dunn). We conclude that atrial muscle from patients taking oral hypoglycemic agents can be preconditioned with exogenous Ca(2+). This therapy may offer a clinically relevant means to precondition the myocardium of diabetics taking oral hypoglycemic agents prior to clinical interventions such as coronary angioplasty or cardiac bypass.
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PMID:Exogenous calcium preconditions myocardium from patients taking oral sulfonylurea agents. 1053 20

By using our database of continuous 18-lead electrocardiographic (ECG) recordings (standard + V3-5R + V7-9) during coronary angioplasty, we selected 68 patients with left circumflex balloon occlusions (posterior ischemia model) or proximal right coronary artery balloon occlusions (right ventricular IRV] ischemia model). ST-segment amplitudes (J + 60 ms) at preangioplasty baseline were subtracted from maximal ST amplitudes during balloon inflation to create a positive or negative change score (deltaST) for each of the 18 leads. DeltaST elevation was used to describe a change in the ST level in the positive direction from baseline, whether or not actual ST elevation from the isoelectric line was present. DeltaST depression was used to describe a change in the ST level in the negative direction from baseline, whether or not actual ST depression from the isoelectric line was present. ST amplitudes from 8 of the 12 standard leads were then used to estimate ST amplitudes at 192 body surface sites spanning the entire anterior and posterior thorax using the transformation technique of Lux. Thoracic distributions of the DeltaST values were displayed on a torso figure, including locations of the 18 lead locations and points of maximal ST elevation and depression. The 192 estimated body surface unipolar leads were compared with 18-lead ECGs (bipolar and unipolar). During 53 left circumflex occlusions, the maximal deltaST elevation was always located in the 18-lead ECG, with the most frequent locations at leads III, II (41%), V7-8 (34%), and V5-6 (25%). The maximal deltaST depression was located outside the 18-lead ECG (89%), with the most frequent locations above standard lead V2 (67%) and V3 (14%). During 16 proximal right coronary artery occlusions, the maximal deltaST elevation was always located in the 18-lead ECG, with the most frequent locations at leads III (81%) and V2-3R (13%). The maximal deltaST depression was located outside the 18-lead ECG (93%), with the most frequent locations above standard lead V2 (50%), V3 (14%), and V4 (14%). We conclude that maximal deltaST elevation is always located in the 18-lead ECG and maximal deltaST depression is frequently located outside of 18-lead ECG during left circumflex and proximal right coronary artery occlusions. Future studies are required to determine the bipolar leads for the 192 estimated body surface potential mapping leads.
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PMID:Thoracic location of the lead with maximal ST-segment deviation during posterior and right ventricular ischemia: comparison of 18-lead ECG with 192 estimated body surface leads. 1126 18


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