Elective aortic-root replacement has a low operative mortality. In contrast, emergency repair, usually for acute aortic dissection, is associated with a much higher early mortality. Because nearly half the adult patients with aortic dissection had an aortic-root diameter of 6.5 cm or less at the time of operation, it may be prudent to undertake prophylactic repair of aortic aneurysms in patients with Marfan's syndrome when the diameter of the aorta is well below that size.

1Inst it ute of A nest hesiology , Hannover Medical School, H annover, FRG Surgery of aneurysms of the thoracic aorta has made great strides in recent years due to progressive standardization of these complex procedure s. Although deep hy po t hermia was used for surgery on the aortic arch as early as 1963 (I), the int roduction of prolonged circulato ry arrest by Griepp (3) and Crawford (2) and their associates has greatly simplified extensive replacement of the aortic arch with or without the ascend ing aorta . Some of these patient s present the formidable problem of further surgery on the downstream por tions of the aorta, the solution of which is greatly facilitated by the "ele phan t trunk" technique described in this report. This innovation allows for the free end of a prosthesis inserted into an upstream segment of the aorta to float freely within the more distal aneurysmatic po rtions of the vessel which is subseq uently replaced requiring only one anasto mosis. The technique was employe d in 2 patients who had un dergone successful replacement of the ascen ding aorta and aortic arch but showe d additional arteriosclerotic aneurysms of either the entire suprarenal aor ta or the descendin g aorta . The patients were 46 and 48 years of age.Replacement of the ascend ing aor ta and arch was perfor med under total circulatory arre st in deep hypothermia with conventi onal end-to-end anastomosis of a fibrin -presealed woven prosthesis to the stump of the proximal ascending aorta , and late ral anastomosis of the origins of the head and neck vessels to the arch section of tha t graft. Rathe r than connec ting the end of the arch por tion of the prosthesis in end-to-en d fashio n wit h the origin of the descending aorta, an anastomos is was made to the circumference of the graft at this level. Its 10 em long free end was pushed down into the dista l aneury sm to float freely within its lumen . During the rewarming phase the aorta was perfused antegradely.In both patie nts replacement of the descend ing tho racic aneurysm was performed in a second operation which simply involved anastomosing the "elephant trunk" to the distal descendi ng aorta. The description of the procedure will be limited to t he first of t he 2 patient s. Fig. I shows the extent of t he aneurysm (a) and the diagrammatic appearance of the repair aft er ascending aortic and arch replacement (b). Note the "e lephant tru nk" protruding into the descending aortic aneurysm.Ten weeks afte r t he first operation, replacement of the descend ing thoracic aorta was performed (5 -24-1982) via "Ded icated to Prof. Dr. Rudolf Zenker on the occasion of his 80 th birthday a 5th left intercostal incision, clamping the aorta well below the o rigin of the left subclavian artery and at the level of the 8th intercostal space , where a narrow segment was present (Fig. 1). The aneury sm was then incised and the graft was locat ed within t he lumen (Fig. 2a) .It was cleaned of densely adhering thrombus and extended. Rather than anastomosing its en ds to the distal ...

The Port-Access system allows for video-assisted minimally invasive replacement and complex repair of the mitral valve through a right lateral minithoracotomy. However, morbidity and mortality associated with this novel technique were high.

The relationship between the degree of pulmonary inflation and the pulmonary vascular resistance was studied in an open-chested dog preparation. It was possible to control the state of inflation and the blood flow to the lung under study. Vascular resistance could then be observed under controlled conditions. In most cases the resistance at complete collapse was very slightly higher than at moderate levels of inflation. In a few instances collapse was associated with a more marked elevation of resistance. Higher levels of inflation resulted in elevation of vascular resistance. At high levels of pulmonary blood flow and pulmonary arterial pressure, the flow resistance curve is lower than at low levels of blood flow. The resistance values obtained during deflation of the lung were consistently different at equal transpulmonary pressures from those obtained during inflation. The possible reasons for this hysteresis are discussed. Evidence is presented that the increased resistance at high levels of lung inflation is due to the effect of transpulmonary pressure on the vessels surrounding the alveoli. Submitted on January 11, 1960

A method has been developed by which flow to each lung, as well as pulmonary artery and left atrial pressures can be measured and varied at will. Vascular resistances were determined over a wide range of these variables. Both pressures have a marked effect on vascular resistances; the higher either pressure, the lower the resistances. This effect is most marked at low levels of pressure and flow. The absolute levels of the pressures, by affecting vascular distension, are major determinants of pulmonary vascular resistance.T HE existence of vasomotor activity in the pulmonary vascular bed is well established, though the degree and significance of such activity have been much debated. Recent interest has focused on the influence of hypoxia and drugs on pulmonary vascular reactions, and on changes of pulmonary vascular resistance associated with mitral stenosis and certain types of congenital heart disease. Confusion exists in this subject because of insufficient knowledge of the mechanical factors which influence resistance. Changes of vasomotor tone can be inferred only if the background of mechanical factors is sufficiently known. Since the pulmonary vascular bed is a highly distensible system, one would expect that changes of luminal pressure might have a large effect on resistance through changes of caliber of the system. Some information on this effect has been provided by the work of