Cardiovascular diseases最新文献

Chronic popliteal arteriovenous fistula is a common result of penetrating vascular trauma. Such a case, involving a young, active-duty soldier who received a gunshot wound to the back of his left leg, is reported. Operative findings confirmed the presence of a fistula and a dilated, tortuous popliteal vein. A 1-cm communication between the main popliteal vein and artery just above the knee was found. Division, with lateral venorrhaphy and end-to-end repair of the artery, was performed, with good results. Particularly stressed in this report is the importance of increased physician awareness, combined with an aggressive surgical approach to reduce the morbidity, especially the high amputation rate so often associated with this kind of penetrating vascular trauma.

Closure of a Waterston shunt can usually be performed at the time of corrective surgery, either from the inside of the aorta or by detaching it from outside the aorta and patching the pulmonary artery. We propose a different approach for closing the shunt and repairing pulmonary artery stenosis.

The bulbar conjunctiva is one of the few areas in which blood flow in the peripheral vasculature can be directly and noninvasively observed in the human. Although extensive literature exists describing morphological changes which correlate with a variety of systemic diseases in this vasculature, little quantitative data is available on hemodynamics in either normal or abnormal states. The hemodynamic data available are primarily subjective assessments of "low flow." Approaches to place the subjective assessment on more quantitative grounds have usually been based on photographic techniques that have intrinsic inadequacies. The objective of the work reported here was to develop a system capable of providing sequential blood velocity data potentially useful for providing quantitative information on blood flow and its change in the microvessels of the human conjunctiva. The method that has evolved uses a standard Zeiss slit-lamp to image a subject's conjunctival vessels by using a 1-inch Newvicon TV camera with an electronic magnification of 2x. The video image is simultaneously recorded on a video tape recorder (VTR) to an overall system magnification of approximately 4 microm/raster line. The data acquisition phase requires approximately 5 minutes of patient time, whereas the actual determination of blood velocity in individual vessels is done offline through a modification of the dual-slit videodensimetric method. Two independently controllable video cursors are placed axially over the vessel image with the VTR in the still-frame mode. For each consecutive video field, the position of two reference points on the vessel and the position of each cursor relative to these and to each other are encoded into a computer to track the moving image caused by normal eye movement. The computer then determines new cursor coordinates to ensure a constant position within the vessel. The electrical signals obtained for each cursor site and for each video field are cross-correlated to yield the average blood velocity over the sampled time interval. The system has been calibrated in vitro from 0.2 to 2.5 mm/sec, evaluated in experimental animals, and used to measure blood velocity (0.3 to 1.5 mm/sec) in human conjunctival venules with diameters ranging from 20 to 50 microm. At this writing, blood velocity has been recorded during a period of about 3 months in the same vessel of several postmyocardial infarction patients. Thus, the method appears suitable for determining sequential changes in small vessel blood flow in patients over extended periods of time.

Three patients with situs inversus totalis (mirror-image dextrocardia) and concomitant coronary artery disease were admitted to our institution for evaluation. In all cases, aortocoronary bypass grafting was successful. Patients with situs inversus and mirror-image dextrocardia are believed to have normal longevity, and, as these studies suggest, they have the same long-term prognosis after coronary bypass grafting as patients with situs solitus.

The distribution in the myocardium of cardioplegic solution is demonstrated in dog hearts with the aid of indocyanine green. When papaverine or nitroglycerin are added to the solution, a much improved diffusion is observed. Papaverine appears to be a better coronary dilator. We deduce from this observation that myocardial protection during ischemic arrest for open-heart surgery is enhanced considerably when coronary dilation is assured.

A malfunction of an oxygenator pumphead during aortocoronary bypass surgery is described. Corrections were made and the operation proceeded without further incident. Although this malfunction is extremely rare, it is reviewed in detail to alert perfusionists to the possibility of such an occurrence.

A case of acute distal aortic thrombosis in an elderly high-risk patient was successfully managed with intraoperative thrombectomy and balloon catheter dilatation of the common iliac arteries. Balloon catheter dilatation may be indicated prior to bypass grafting in high-risk patients with acute aortoiliac thrombosis.

The case of a very young man with Prinzmetal's variant angina and a normal coronary arteriogram is described. While in the hospital for diagnosis, he experienced severe chest pain accompanied by transient ST segment elevation. After intravenous administration of Ergonovine Maleate (0.4 mg), spastic obstruction of the right coronary artery was observed. He was treated successfully with nifedipine, and during 4 months of follow-up, he has had no symptoms. Because of the diagnostic interest in this type of angina in a young person, the literature on Prinzmetal's angina has also been reviewed.

A patient with a dissecting aortic aneurysm, Type 1, developed acute pulmonary edema unexplained by the usual etiologic factors. Pathologic evidence that bronchial arterial circulation was interrupted led us to hypothesize that pulmonary edema could be due to ischemia of the bronchial circulation. To test this hypothesis, two chronic studies were done in dogs. The first study consisted of selective ligation of the right posterior bronchial artery at its origin at the fifth or sixth intercostal artery. After recovery from surgery, biopsies were taken from the ipsilateral and contralateral lung at time periods from 5 hours to 11 days. Ischemic damage was found in seven of eight dogs (87.5%), and was confined to the right lung. Histological examination revealed initial congestion within 8 hours, followed by pulmonary edema within 72 hours, and finally, disruption of alveolar septa with small emphysematous bullae on the eleventh postoperative day. The left lung remained normal in histological appearance. The second study consisted of transplanting the bronchial artery to the pulmonary artery to create a low pressure system and low O(2) content, and to simulate a regional shock situation. In five of six dogs (83.3%), the anastomosis was occluded within 72 hours, probably due to pressure competition from small collateral bronchial circulation. However, in these five dogs, pulmonary vascular resistance increased by 53%, intrapulmonary shunting increased by 83%, and the alveolar-to-arterial oxygen gradient increased by 150 mm Hg. Pulmonary edema was again confined to the right lung. Bronchial arteriograms demonstrated the extensive and variable distribution of the bronchial circulation in dogs. In the sixth dog, the anastomosis remained patent with a left-to-right shunt, due to a larger bronchial arterial collateral circulation. In this animal, the pulmonary arterial resistance, intrapulmonary shunting, and alveolar-arterial O(2) gradient were normal. Pulmonary edema was absent in lung biopsies. Bronchial circulation is discussed with respect to its clinical implications for lung transplants, shock, thoracic aneurysms, and mediastinal surgery. The results of this study suggest that the systemic bronchial circulation is important for normal lung function.