Cardium Therapeutics: Cardiovascular Disease, Coronary Artery Disease and Chronic Angina

CARDIOVASCULAR DISEASE

Market Data for Heart Disease and Angina

According to the World Heart Federation, heart disease is the world’s leading cause of death.
Almost 16 million men and women in the United States suffer from coronary heart disease.
Angina, a serious and debilitating heart condition usually associated with heart disease, is a growing health problem with nearly nine million Americans suffering from chronic angina and an additional 400,000 new diagnoses each year.
The U.S. Census Bureau projects that the over 55 population, the group most at risk for angina, will increase by approximately 70% over the next 30 years.
An estimated 2 million patients in the U.S. suffer from recurrent angina, a chronic condition in patients with heart disease who are receiving maximal drug therapy and have already undergone one or more mechanical interventions for revascularization.

Current Treatments for Heart Disease and Angina

An estimated 7.2 million American women are currently living with coronary heart disease and more than 4.6 million women suffer from angina. Based on the current practice of medicine, angina due to heart disease is treated using one or more of three approaches: (1) chronic drug therapy; (2) percutaneous coronary intervention (angioplasty and stenting); and (3) coronary artery bypass graft surgery.

Currently available drugs to treat angina include beta-blockers, calcium channel blockers, long-acting nitrates, and metabolic modulators. These drugs increase cardiovascular blood flow by vasodilation and decrease the heart’s demand for oxygen by reducing the metabolic load. This reduced cardiac workload is achieved by lowering heart rate, blood pressure and/or the strength of the heart’s contraction. Hemodynamic and other side effects can limit or prevent the use of currently available drugs in patients whose blood pressure or cardiac function is already decreased. These limiting effects can be particularly pronounced when anti-anginal drugs are used in combination. In addition, co-morbidities such as reactive airway disease, congestive heart failure and diabetes also complicate treatment with existing anti-anginal drugs because these conditions may cause patients to be more vulnerable to known side effects associated with these therapies. Potential adverse effects include lower extremity edema with calcium channel blockers, impotence and depression with beta-blockers, and headaches with nitrates. Consequently, for some patients and physicians, presently available medical treatments may not adequately relieve angina and may have unacceptable side effects. Importantly, for many chronic angina patients, currently available therapies may provide variable or incomplete relief. Despite the widespread use of these therapies, up to three-fourths of symptomatic patients have recurrent or persistent anginal symptoms. Many patients, even those on multiple drugs, continue to experience angina attacks.

Of the major interventions performed for treating severe heart disease in the United States, namely percutaneous coronary intervention (PCI or angioplasty) and coronary artery bypass graft (CABG) surgeries, more than one million procedures are performed annually and more than two-thirds of these are performed on men. While angioplasty and stenting or CABG surgeries can be used to mechanically open or surgically bypass blockages of the large epicardial blood vessels that surround the myocardium, neither angioplasty nor CABG are believed to be capable of also addressing blockages or flow limitations affecting the mid-sized to smaller blood vessels that are located deeper within the heart muscle. These deeper blood vessels, which form the underlying coronary “microcirculation,” are directly responsible for conveying oxygenated blood into close proximity with the adjacent heart tissue. In addition, microcirculatory impedance or resistance to flow at the downstream level can contribute substantially to reducing overall blood flow through the myocardium—which may be a contributory cause of ischemia in patients with heart disease. In that regard, many patients continue to experience angina even after surgical and other interventions have been performed to mechanically open or bypass accessible portions of the large upstream blood vessels that initially conduct blood flow into the heart.

Women and Heart Disease

An estimated 7.2 million American women are currently living with coronary heart disease and more than 4.6 million women suffer from angina. The American Heart Association reports that more women’s lives are claimed annually by cardiovascular disease than by the next five leading causes of death combined (all cancers combined, chronic obstructive pulmonary disease (COPD), Alzheimer’s, diabetes and accidents). Despite these stark statistics, surveys indicate that nearly half of women are not aware that heart disease is the leading cause of death among women, and only 20 percent identified heart disease as the greatest health problem facing women today. Women with chronic angina may experience angina differently than men. Only 30% of women with documented coronary heart disease report their major symptom as sub-sternal chest pain. Women are more likely to experience unusual fatigue, sleep disturbances, gastrointestinal symptoms or shortness of breath. Observed differences between men and women with coronary heart disease are not fully understood. Some researchers believe the differences may be the result of microvascular disease, the narrowing or stiffening of the smaller arteries and arterioles that nourish the heart. While microvascular disease is believed to affect both men and women with coronary heart disease, the prevalence is apparently somewhat higher in women and in patients with diabetes.