Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
1996-09-17
2001-05-01
Jackson, Gary (Department: 3731)
Surgery
Instruments
Internal pressure applicator
C604S096010, C606S201000
Reexamination Certificate
active
06224619
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to cardiovascular surgical apparatus. More particularly, the invention relates to apparatus, a principle function of which is to more safely occlude the ascending aorta during the performance of surgery, such as open-heart surgery or minimally invasive cardiac surgery. Specifically, the invention relates to apparatus which may change size or shape, or both, during such use.
2. Description of Related Art
In many surgical procedures it is necessary to occlude a blood vessel in order to provide the surgeon with a bloodless field in which to work. Such occlusion is most commonly effected by the application of a vascular clamp to the concerned region of the blood vessel. In the performance of most open heart surgical procedures where occlusion of the ascending aorta is essential, however, the use of a vascular clamp for clamping this vessel creates a condition susceptible to serious negative consequences that the surgeon cannot completely control. For example, while the use of a vascular clamp to occlude the aorta provides a quick and easy occlusion of the vessel, clamping the aorta can disrupt the aortic wall, thereby dislodging degenerative plaque-like material, which is capable of migrating to the brain thereby resulting in a stroke. Other consequences can also result from clamping the aorta. For example, the dislodged particles may migrate to other parts of the body thereby creating the danger of limb gangrene in the extremities, such as the arms or legs, or damage to certain organs as, for example, the kidney, the liver or the small or large bowel. Alternatively, in clamping the aorta, the wall may rupture thereby resulting in hemorrhage. Each of these complications can cause serious morbidity and often times may result in death.
It is to the amelioration of these problems, therefore, to which the present invention is directed.
SUMMARY OF THE INVENTION
In accordance with a principle aspect of the present invention there is provided an occluder apparatus for obstructing the flow of blood in a blood vessel comprising an elongated hollow tubular body having a leading end sized for reception in said blood vessel, means for inserting said body through the wall of said blood vessel to extend said leading end into the interior of said blood vessel, an inflatable diaphragm carried in a collapsed, deflated condition within the interior of said body, means for conducting an inflating fluid from an external source into fluid communication with the interior of said diaphragm to effect expansion thereof, means in said body to enable release of said diaphragm in an inflated state from said body into flexible occluding engagement with the interior wall of said blood vessel about substantially the full circumference of a section thereof.
The invention contemplates use with the described occluder device of an external belt-like blood vessel wall-compressing device adapted to surround the blood vessel and apply a compressive force in opposed relation to the force applied by the occluder diaphragm. By use of the belt-like compressing device the blood vessel can be effectively occluded by the diaphragm without distention or distortion of the wall thereof thus to prevent flexure of the wall and dislodgement therefrom of fragile material that could create a dangerous condition in the patient.
Apparatus according to the invention can be particularly designed to facilitate several procedures common to open-heart surgery. For example, besides obstructing the flow of blood to the heart to create a quiescent region within which the surgeon can work, the apparatus can be designed to be useful in the introduction of myocardial preservation solution to the proximal region of the aorta. On the other hand, the passage designed to conduct myocardial solution can, alternatively, be connected to a pressure measuring device for monitoring aortic root pressure. Similarly, the passage can be employed for venting the aortic root and/or clearing the heart and aortic root of blood and/or air. Importantly, the apparatus can also be made to perform as an aortic arterial perfusion cannula for circulating blood between a heart-lung machine and the patient in bypass relation to the occluded region of the aorta and the heart.
To accomplish the purpose and function of the intravascular occluding device a compromise is made between the shape and size required to introduce the device and the shape and size of the device to perform its functions once it is intraluminal in a vessel. A device capable of altering its size or shape, or both, once it is placed intravascularly may satisfy both the size and shape requirements for insertion as well as the shape and size requirements for the medical function of the device once it is positioned in a vessel. The device may have the ability to alter its size and shape, or both, by fabricating a portion or portions of the device from materials soluble in a medium, such as a medium comprising blood. The portion or portions of the device may dissolve once it is positioned intravascularly, and that portion or those portions come in contact with the medium. The portion or portions of the device, which are fabricated from materials that are not soluble in the medium, are of a size or shape, or both, permitting the device to perform the desired medical function once it is intravascular. The solubility of the portion or portions of the device is dependent on (1) the material or the combination of materials, from which the device was fabricated, and (2) the type and characteristics of the medium to which the soluble portion or portions of the device is (are) exposed.
The soluble material may be organic, e.g., sugars, or inorganic, e.g., salts. Suitable soluble organic material may be selected from the group consisting of carbohydrates, such as glucose, sucrose, and mannitol; proteins; gelatins; plastics; lipids and lipid compounds; and polyethyl glycol, and combinations thereof Similarly, soluble inorganic material may be selected from the group consisting of sodium chloride and sodium bicarbonate and the like. Moreover, the soluble portion or portions may include a plurality of layers of soluble material, each of the plurality of layers having solubility characteristics different from at least another of the plurality of layers. Alternatively, the soluble portion or portions may include a honeycomb structural material and a honeycomb filling material, such that the honeycomb structural material and the honeycomb filling material have different solubility characteristics. For example, with respect to a particular medium, a portion or portions of a trocar body may include a non-soluble or soluble honeycomb structural material and a comparatively more soluble honeycomb filling material.
The medium may comprise a water-based medium, such as blood. Such blood may have hematocrit in a range of about 5 to 65%; hemoglobin in a range of about 2 to 18 grams; white blood cells in a range of about 1,000 to 50,000/cm
2
; and platelets in a range of about 10,000 to 500,000/cm
2
Further, the blood may be saturated with oxygen in a range of about 5 to 100%, may include a partial pressure of carbon dioxide in a range of about 20 to 100 mmHg, and may have plasma proteins in a range of less than about 8%, e.g., about 6 to 8%, by weight. It may also include inorganic substances in a range of about 0.1 to 2% by weight and may have a pH in the ranges of about 6.5 to 7.9. In another embodiment, the blood may be in various degrees of hemodilution with such substances as dextrose and water, saline, Ringer's Lactate, or plasma expanders. The blood also may have various pharmacological substances dissolved in it as may be given to a patient during medical treatment or in preparation for surgery, or both. The temperature of the medium may be in a range of about 1 to 41° C., but generally, the soluble portion or portions will dissolve more rapidly as the temperature of the medium increases.
In an embodiment, an occluder apparatus for obstruct
Baker & Botts L.L.P.
Heartport Inc.
Jackson Gary
Trinh Vikki
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