Surgery – Internal organ support or sling
Reexamination Certificate
2002-01-08
2003-04-01
Hindenburg, Max F. (Department: 3736)
Surgery
Internal organ support or sling
Reexamination Certificate
active
06540666
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a method and apparatus for treating congestive heart disease and related valvular dysfunction. More particularly, the present invention is directed to an adaptive cardiac constraint having an outer non-extentible device and a pair of inner inflatable members for preventing over-extension of the heart during diastole.
BACKGROUND OF THE INVENTION
Congestive heart disease is a progressive and debilitating illness. The disease is characterized by a progressive enlargement of the heart. As the heart enlarges, the heart is performing an increasing amount of work in order to pump blood each heart beat. In time, the heart becomes so enlarged the heart cannot adequately supply blood. An afflicted patient is fatigued, unable to perform even simple exerting tasks and experiences pain and discomfort. Further, as the heart enlarges, the internal heart valves may not adequately close. This impairs the function of the valves and further reduces the heart's ability to supply blood.
Causes of congestive heart failure (CHF) are not fully known. In certain instances, CHF may result from viral infections. In such cases, the heart may enlarge to such an extent that the adverse consequences of heart enlargement continue after the viral infection has passed and the disease continues its progressively debilitating course.
With initial reference to
FIGS. 1 and 1A
, a normal, healthy human heart H′ is schematically shown in cross-section and will now be described in order to facilitate an understanding of the present invention. In
FIG. 1
, the heart H′ is shown during systole (i.e., high left ventricular pressure). In
FIG. 1A
, the heart H′ is shown during diastole (i.e., low left ventricular pressure).
The heart H′ is a muscle having an outer wall or myocardium MYO′ and an internal wall or septum S′. The heart H′ has four internal heart chambers including a right atrium RA′, a left atrium LA′, a right ventricle RV′ and a left ventricle LV′. The heart H′ has a length measured along a longitudinal axis BB′-AA′ from an upper end or base B′ to a lower end or apex A′.
The right and left atria RA′, LA′ reside in an upper portion UP′ of the heart H′ adjacent the base B′. The right and left ventricles RV′, LV′ reside in a lower portion LP′ of the heart H′ adjacent the apex A′. The ventricles RV′, LV′ terminate at ventricular lower extremities LE′ adjacent the apex A′ and spaced therefrom by the thickness of the myocardium MYO′.
Due to the compound curves of the upper and lower portions UP′, LP′, the upper and lower portions UP′, LP′ meet at a circumferential groove commonly referred to as the A-V (atrio-ventricular) groove AVG′. Extending away from the upper portion UP′ are plurality of major blood vessels communicating with the chambers RA′, RV′, LA′, LV′. For ease of illustration, only the superior vena cava SVC′, inferior vena cava IVC′ and one of the left pulmonary vein LPV′ are shown as being representative.
The heart H′ contains valves to regulate blood flow between the chambers RA′, RV′, LA′, LV′ and between the chambers and the major vessels, aorta and preliminary artery. For ease of illustration, not all of such valves are shown. Instead, only the tricuspid valve TV′ between the right atrium RA′ and right ventricle RV′ and the mitral valve MV′ between the left atrium LA′ and left ventricle LV′ are shown as being representative.
The valves are secured, in part, to the myocardium MYO′ in a region of the lower portion LP′ adjacent the A-V groove AVG′ and referred to as the valvular annulus VA′. The valves TV′ and MV′ open and close through the beating cycle of the heart H.
FIGS. 1 and 1A
show a normal, healthy heart H′ during systole and diastole, respectively. During systole (FIG.
1
), the myocardium MYO′ is contracting and the heart assumes a shape including a generally conical lower portion LP′. During diastole (FIG.
1
A), the heart H′ is expanding and the conical shape of the lower portion LP′ bulges radically outwardly (relative to axis AA′-BB′).
The motion of the heart H′ and the variation in the shape of the heart H′ during contraction and expansion is complex. The amount of motion varies considerably throughout the heart H′. The motion includes a component which is parallel to the axis AA′-BB′ (conveniently referred to as longitudinal expansion or contraction). The motion also includes a component perpendicular to the axis AA′-BB′ (conveniently referred to as circumferential expansion or contraction).
Having described a healthy heart H′ during systole (
FIG. 1
) and diastole (FIG.
1
A), comparison can now be made with a heart deformed by congestive heart disease. Such a heart H is shown in systole in FIG.
2
and in diastole in FIG.
2
A. All elements of diseased heart H are labeled identically with similar elements of healthy heart H′ except only for the omission of the apostrophe in order to distinguish diseased heart H from healthy heart H′.
Comparing,
FIGS. 1 and 2
(showing hearts H′ and H during systole), the lower portion LP of the diseased heart H has lost the tapered conical shape of the lower portion LP′ of the healthy heart H′. Instead, the lower portion LP of the diseased heart H dilates outwardly between the apex A and the A-V groove AVG. So deformed, the diseased heart H during systole (
FIG. 2
) resembles the healthy heart H′ during diastole (FIG.
1
A). During diastole (FIG.
2
A), the deformation is even more extreme.
As a diseased heart H enlarges from the representation of
FIGS. 1 and 1A
to that of
FIGS. 2 and 2A
, the heart H becomes a progressively less efficient pump. Therefore, the heart H requires more energy to pump the same amount of blood. Continued progression of the disease results in the heart H being unable to supply adequate blood to the patient's body and the patient becomes symptomatic of cardiac insufficiency.
For ease of illustration, the progression of congestive heart disease has been illustrated and described with reference to a progressive dilation of the lower portion LP of the heart H. While such enlargement of the lower portion LP is most common and troublesome, enlargement of the upper portion UP may also occur.
In addition to cardiac insufficiency, the enlargement of the heart H can lead to valvular disorders. As the circumference of the valvular annulus VA increases, the leaflets of the valves TV and MV may spread apart. After a certain amount of enlargement, the spreading may be so severe the leaflets cannot completely close. Incomplete closure results in valvular regurgitation contributing to an additional degradation in cardiac performance. While circumferential enlargement of the valvular annulus VA may contribute to valvular dysfunction as described, the separation of the valve leaflets is most commonly attributed to deformation of the geometry of the heart H.
Patients suffering from CHF are commonly grouped into four classes (i.e., Classes I, II, III and IV). In the early stages (e.g., Classes I and II), drug therapy is the most commonly prescribed treatment. Drug therapy treats the symptoms of the disease and may slow the progression of the disease. However, drugs may have adverse side effects. There is no cure for CHF; even with drug therapy, the disease will progress.
CHF is encountered with increasing frequency. Most of this increase can be attributed to the aging population. An estimated 4-5 million people in the United States have CHF with 400,000 new cases annually. This is an estimated 2,000 new cases annually per 1.5 million people. For those with advanced CHF, mortality is a
Godfrey & Kahn S.C.
Heart Care Associates, LLC
Hindenburg Max F.
Srivastava Sonali
Veniaminov Nikita R
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