A heart is illustrated in FIG. 1, and is generally designated by the reference letter H. The heart H includes a right atrium RA, a left atrium LA, a right ventricle RV, a left ventricle LV, a pulmonary artery PA, and an aorta A. The aorta A includes an intimal (inner) layer or intima IL (FIG. 2) and an adventitial (outer) layer or adventitia AL.
In Type A aortic dissection, the intimal (inner) layer or intima IL is torn and defines a tear T in the ascending aorta AA or aortic arch. Blood B collects in (unnumbered) between the layers AL, IL. This is referred to as a false lumen. If the blood collection continues, the false lumen may block off origin of major arteries coming off the aorta, thus causing abrupt lack of blood flow to the involved organ, causing its death. This condition may be fatal, or cause of major morbidity, if not treated urgently.
Treatment may necessitate dissection of an aortic portion AP of the aorta A containing the portion with intimal tear along lines of dissection LD1, LD2, and replacement of the cutout portion of the aorta by a Dacron® tube graft of appropriate size. More particularly, the dissection along lines of dissection LD1, LD2 may separate a distal end or end portion Ea of the ascending aorta AA from a proximal end or end portion Ed of the ascending aorta AA. The two ends or end portions Ea, Ed of the ascending aorta AA, after the dissected aorta portion AP and particularly the intimal portion thereof has been excised, are still quite fragile and the two layers AL, IL are still separated. The two ends Ea, Ed may be prepared for the Dacron® tube graft by suturing the respective ends Ea, Ed and buttressing them with strips of Dacron® or felt both on the inside and the outside of the ends Ea, Ed. After both ends Ea, Ed are prepared, the Dacron® tube graft is anatamosed to restore the continuity of the aorta and establish blood flow.
The treatment described above may take a considerable length of time using prior art methods and devices. During the treatment, the patient is on cardiopulmonary bypass (heart-lung) machine. For part of the time, all circulation is stopped. On average, a patient may be on the heart-lung machine for three hours and 20 minutes, and the average time of a patient's circulation being stopped is 34-40 minutes. The lengths of these times contribute to the increased risk of stroke, bleeding, and death. In particular, at the time of preparation of this material, the operative mortality rate is 17.84%, post-op neuro deficit is 10.3%, and re-exploration for bleeding is 16.5%. Thus, there is need to reduce the length of time that it takes to carry out the treatment of replacing a cutout portion of the aorta with a tube graft of appropriate size.
USPTO Backgrounds
USPTO Backgrounds