Drug – bio-affecting and body treating compositions – Inorganic active ingredient containing – Nitrates or nitrites or nitric acid or nitrogen oxides
Reexamination Certificate
2000-04-11
2001-09-11
Criares, Theodore J. (Department: 1617)
Drug, bio-affecting and body treating compositions
Inorganic active ingredient containing
Nitrates or nitrites or nitric acid or nitrogen oxides
Reexamination Certificate
active
06287608
ABSTRACT:
FIELD OF THE INVENTION
The invention generally relates to the treatment of kidneys by direct application of a vasodilator agent. In particular, the invention relates to a method and apparatus to treat patients with congestive heart failure by reducing resistance to blood flow to the patient's kidney by direct infusion of a vasodilator drug.
BACKGROUND OF THE INVENTION
A. Congestive Heart Failure
Congestive heart failure (CHF) is a serious condition affecting an estimated 5 million Americans. Increasing prevalence, hospitalizations, and deaths have made CHF a major chronic health condition in the United States. There are an estimated 400,000 new cases of CHF each year. These cases are often first diagnosed as the end stage of cardiac disease. The average mortality rate of CHF is 10 percent after the 1st year and 50 percent after 5 years. Thus, half of the patients diagnosed with CHF will die within 5 years of their diagnosis.
The magnitude of the problem is expected to get much worse as more cardiac patients are able to survive and live longer. As patients live longer, the potential for developing CHF increases. In addition, because the incidence of heart failure rises substantially beyond age 65, the prevalence of this condition is likely to increase as the population ages.
The high prevalence of heart failure and the resulting high cost of caring for these patients places a significant economic burden on society. The American Heart Association statistics report that, including medications, an estimated $22.5 billion will be spent for the care of CHF patients in hospitals, physicians offices, home care, and nursing homes including medications in the year 2000. In light of the high costs and poor prognosis of CHF, there is a pressing need to prevent this condition and provide better clinical management to reduce morbidity and mortality.
Congestive heart failure (CHF) is a diseased condition in which the heart fails to function efficiently as a pump to provide sufficient blood flow and/or pressure to fulfill the normal circulatory needs of a patient. CHF results in sudden shortness of breath, fainting and irregular heart beats that require frequent emergency room treatments (acute CHF), and in its chronic form leads to repeated hospital stays, deteriorating quality of life and significant costs to the health care system. Congestive heart failure is characterized by: (1) signs and symptoms of intravascular and interstitial volume overload, including shortness of breath, fluid in the lungs, and edema, and (2) manifestations of inadequate tissue perfusion, such as fatigue or poor exercise tolerance. These signs and symptoms result when the heart is unable to generate a cardiac output sufficient to meet the body's demands.
In CHF, the failing heart is not able to generate sufficient blood pressure to properly perfuse the kidneys, e.g., provide sufficient blood pressure to force blood through the kidneys and filter the blood. In a patient suffering from chronic heart failure, the blood pressure tends to progressively decrease as the heart progressively fails over weeks, months or years. With the decrease in blood pressure there is a concomitant decrease in organ perfusion. Accordingly, chronic heart failure can lead to chronic impaired renal perfusion.
Chronic heart failure patients frequently evolve into acute CHF and are admitted to hospital with an abrupt worsening of their condition. During these periods of acute hypotension (or low blood pressure) their kidneys arc particularly at risk from decreased renal blood flow and may be severely injured. In some cases the blood pressure of these patients can be normal but at the expense of the total shutdown of the blood flow to the kidneys.
B. Relationship of Kidney Failure to CHF
The kidneys are a pair of organs that lie in the back of the abdomen on each side of the vertebral column. They play an important regulatory role in maintaining the homeostatic balance of the body. The kidneys function like a complex chemical filtering plant. They eliminate foreign chemicals from the body, regulate inorganic substances and the extracellular fluid, and function as endocrine glands, secreting hormonal substances like renin and erythropoietin.
The main functions of the kidney are to maintain the water balance of the body and control metabolic homeostasis. The kidneys regulate the amount of fluid in the body by making the urine more or less concentrated, thus either reabsorbing or excreting more fluid, respectively. The kidneys also extract undesirable chemicals and concentrate them in urine, while allowing the reabsorption of other chemicals.
The kidney processes of filtration, reabsorption and fluid regulation take place in the renal nephron of the kidney. Within the nephron the smallest circulatory vessels, capillaries and arterioles, form a glomerulus. The glomerulous is intimately associated with the renal tubules to filter wastes from the blood, remove excess water from the body and produce concentrated urine. The glomerular filtration rate (GFR) is a clinical indicator universally accepted as a measure of the ability of the kidney to remove fluid and solutes. GFR is the summary of the physiologic functions of the kidneys.
The kidneys remove the deleterious metabolic products from the blood, which represents a small portion of the total blood volume. The blood is repeatedly circulated through the kidney several times during each day to remove the required amount of these deleterious metabolic products. In a healthy person, the kidney receives approximately 10% of the cardiac output which is the total body blood flow (about 0.5 liters per minute) which, over the course of a day, amounts to 720 liters per day of blood passing through each kidney. Significantly more blood fluid is filtered through the kidneys than is excreted as urine. Most of the filtered blood fluid must be reabsorbed into the circulatory system to maintain the fluid balance of the body.
Without properly functioning kidneys, a patient will suffer water retention, reduced urine flow and an accumulation of wastes toxins in the blood and body. These conditions resulting from reduced renal function or renal failure (kidney failure) are believed to increase the workload of the heart. In a CHF patient, renal failure because of decreased renal perfusion will cause the heart to further deteriorate. Water and blood toxins accumulate due to the poorly functioning kidneys and in turn, cause the heart further harm.
Fluid overload during CHF is caused in two ways. First, activation of neurohormonal mechanisms of the renin-angiotensin system and aldosterone activation leads to peripheral vasoconstriction and retention of salt, thus water by the kidney. Second, the persistent lower renal blood flow and pressure cannot generate adequate hydrostatic pressure to make sufficient urine to remove excess retained fluid. Accordingly, the kidneys are a principal non-cardiac cause of a progressive fluid overload condition in a patient suffering from CHF.
Patients with CHF can also suffer episodes of acute, severe deterioration caused by abrupt decreases in heart function. These episodes are characterized by rapid reductions in blood pressure and flow, especially to the kidney. Similarly to the chronic state, acutely reduced kidney perfusion can result in a sudden, massive retention of fluid leading to pulmonary edema (fluid in lungs). This acute fluid overload taxes an already overburdened heart and can lead to the severest of complications: acute renal failure and death.
C. Prior Kidney Treatments for CHF
To treat CHF, the physicians must fight the body's attempt to inflict itself harm. Physicians can treat the patient with medications that improve the pumping ability of the heart, increase blood pressure and attempt to reactivate a more normal behavior of the body's control (homeostatic) system. Heart failure patients are put on a strict low sodium diet and their fluid intake is monitored. Some patients are limited to as little as one liter of fluid a day. Diuretics are a class
Gelfand Mark
Levin Howard R.
Criares Theodore J.
Intellicardia, Inc.
Kim Jennifer
Nixon & Vanderhye P.C.
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