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Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A detailed pathological study was made in 10 patients dying up to 13 months after aortocoronary saphenous vein bypass grafting for coronary atherosclerosis. The coronary arteries and vein grafts were investigated by injection with a radio-opaque mass, radiography, dissection, and histology. The report is to some extent historical since the patients died during a period when the operation was first being introduced into two cardiothoracic hospitals. About 80 operations were performed during the time the 10 deaths occurred, a mortality of 12-5 per cent (including cases followed up to 13 months after operation). Seven of the patients were operated on for intractable angina and 3 with a view to aneurysmectomy. All the patients selected for operation were severely disabled despite medical treatment. The main cause of death was extremely severe coronary artery disease and its effects on the left ventricle; in one case, over two-thirds of the left ventricle had been destroyed by infarction before operation. Other causes or contributing causes of death were pulmonary embolism, myocardial infarction complicating angiography (ostial stenosis), and cerebral damage. Ten of the 14 vein grafts (71%) were patent at necropsy. A free flow of injection medium usually occurred between patent grafts and coronary arteries. Thrombosis of a graft was thought to have contributed to death in 3 patients, but not in a fourth who died of pulmonary embolism. Since thrombosis of grafts was usually secondary to poor run-off blood into severely atheromatous coronary arteries, this was also an indirect effect of the advanced coronary arterial disease. In one case, thrombosis followed severe chronic intimal thickening of a graft in place for 13 months. The study of these deaths emphasizes that in some patients the pathological changes in the coronary arteries and left ventricle are too severe for them to benefit from surgery. Vein grafts cannot be expected to distribute blood effectively through grossly narrowed coronary arteries. In addition, when a large part of the left ventricle is infarcted or scarred, it is almost certain that improving the blood supply by grafting will not result in significant regeneration of cardiac muscle. Since the time when this study was made, there have been few deaths among the many vein graft operations subsequently carried out in the hospitals involved. The two most important factors thought responsible for the improvement are the selection of cases more suitable for surgery by continued improvement of diagnostic techniques, and also the employment of more radical surgical procedures in the form of coronary endarterectomy and the insertion of more grafts per patient.
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PMID:Pathology of hearts after aortocoronary saphenous vein bypass grafting for coronary artery disease, studied by post-mortem coronary angiography. 108 91

Pulmonary emboli may impair myocardial performance, causing declines in cardiac index (CI) and right and left ventricular stroke work (LVSW) because of mechanical events. We postulate that embolism also leads to the generation of a humoral factor(s) that may reduce cardiac contractility. Eleven mongrel dogs were infused with 0.5 gm/kg clot. Decreases in CI and LVSW were observed 1 hour after embolization. The stable metabolites of prostacyclin and thromboxane (Tx) A2--6-keto-PGF1 alpha and TxB2, respectively--increased within 30 minutes (P less than 0.005, P les than 0.001) and then decreased. These changes did not correlate with the declines in CI or LVSW. Plasma from embolized animals used to bathe an isolated rat papillary muscle reduced developed tension (Tpd) (P less than 0.001) and decreased calcium ATPase (Ca++-ATPase) activity of a myofibril preparation (P less than 0.001) obtained from rat cardiac muscle. The correlation between the reduction of TPd and myofibril Ca++-ATPase activity was 0.72 (P less than 0.001). The decline in Ca++-ATPase was also related to the decreases in CI (r = 0.59, P less than 0.001) and LVSW (r = 0.57, P less than 0.001). Five animals pretreated with indomethacin prior to embolization had no decrease in LVSW as compared with controls (P less than 0.001). Postembolism plasma did not depress papillary muscle Tpd and did not lower Ca++-ATPase activity of myofibrils. Anesthesia itself did not alter cardiopulmonary function. These results suggest that pulmonary emboli cause the release of a negative inotropic agent(s) into plasma that affects energy availability in the heart and reduces contractility. The production of this agent(s) is inhibited by indomethacin pretreatment.
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PMID:Circulating negative inotropic agent(s) following pulmonary embolism. 646 Oct 81

The cardiac muscle activation or driver function, is a major determinant of cardiovascular dynamics, and is often approximated by the ratio of the left ventricle pressure to the left ventricle volume. In an intensive care unit, the left ventricle pressure is usually never measured, and the left ventricle volume is only measured occasionally by echocardiography, so is not available real-time. This paper develops a method for identifying the driver function based on correlates with geometrical features in the aortic pressure waveform. The method is included in an overall cardiovascular modelling approach, and is clinically validated on a porcine model of pulmonary embolism. For validation a comparison is done between the optimized parameters for a baseline model, which uses the direct measurements of the left ventricle pressure and volume, and the optimized parameters from the approximated driver function. The parameters do not significantly change between the two approaches thus showing that the patient specific approach to identifying the driver function is valid, and has potential clinically.
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PMID:Patient specific identification of the cardiac driver function in a cardiovascular system model. 2062 83