Cardiovascular disease

Cardiovascular disease comprises disorders of the heart and blood vessels that impair circulation, damage vascular tissue, or disrupt the mechanical and electrical functions of the heart. The category includes coronary artery disease, cerebrovascular disease, peripheral artery disease, heart failure, and several diseases of the cardiac valves or aorta. Congenital abnormalities and primary rhythm disorders are also cardiovascular conditions, although epidemiological usage often emphasizes diseases acquired during adulthood.

Cardiovascular disease is a leading cause of mortality and long-term disability worldwide. Its population burden reflects the interaction of biological aging with cumulative exposure to elevated blood pressure, atherogenic lipoproteins, tobacco smoke, metabolic dysfunction, and adverse social or environmental conditions. The clinical manifestations vary according to the organ affected and the rate at which circulatory impairment develops. Sudden obstruction of a coronary artery can produce myocardial infarction, whereas gradually increasing vascular resistance can contribute to ventricular remodeling and chronic heart failure.

Pathophysiology

Atherosclerotic vascular disease

Atherosclerosis is the principal pathological process underlying coronary artery disease, ischemic stroke, and peripheral artery disease. It develops within the innermost layer of medium-sized and large arteries after sustained retention of apolipoprotein B-containing particles, particularly low-density lipoprotein. Modification of these particles within the arterial wall activates endothelial cells and recruits circulating monocytes. The monocytes differentiate into macrophages, ingest lipid, and form foam cells within an expanding atherosclerotic lesion.

As lesions mature, vascular smooth-muscle cells migrate and produce extracellular matrix, creating a fibrous cap over a lipid-rich and inflammatory core. Plaque enlargement can progressively narrow the arterial lumen, although outward remodeling of the vessel may initially preserve blood flow. Clinical events frequently result from rupture or erosion of the plaque surface rather than from gradual narrowing alone. Exposure of thrombogenic material then promotes platelet activation and coagulation, potentially producing an occlusive thrombus.

The consequences depend on the vascular territory involved. Coronary thrombosis causes acute myocardial ischemia, while cerebral arterial occlusion causes ischemic stroke. Atherosclerosis affecting the lower limbs reduces perfusion during exertion and may eventually produce pain at rest, tissue loss, or limb-threatening ischemia.

Hypertensive injury and cardiac remodeling

Hypertension subjects arteries and cardiac chambers to persistently increased mechanical stress. Small arteries undergo structural remodeling that narrows their lumina and impairs regulation of tissue perfusion. Within the heart, increased systemic resistance raises the pressure against which the left ventricle contracts. Cardiomyocytes enlarge in response, producing left ventricular hypertrophy and initially maintaining cardiac output.

Prolonged hypertrophy is associated with interstitial fibrosis, impaired relaxation, and increased myocardial oxygen demand. These changes can culminate in heart failure despite preservation of the measured ejection fraction. Hypertension also accelerates atherosclerosis and increases the likelihood of intracerebral hemorrhage through degenerative changes in small cerebral vessels.

Myocardial dysfunction

Heart failure is a clinical syndrome in which structural or functional cardiac abnormalities prevent adequate circulation or require abnormally elevated filling pressures. Reduced contractile function commonly follows myocardial infarction, chronic ischemia, inflammatory injury, or a primary cardiomyopathy. Other patients retain normal or near-normal ejection fraction but develop stiff ventricles that fill only at high pressure.

Compensatory activation of the sympathetic nervous system and the renin–angiotensin–aldosterone system initially supports arterial pressure and organ perfusion. Persistent activation promotes vasoconstriction, sodium retention, cellular injury, and adverse ventricular remodeling. Rising venous pressure subsequently causes pulmonary congestion or systemic edema, depending on which cardiac chambers are predominantly affected.

Thrombosis, embolism, and hemorrhage

Not all major cardiovascular events arise from atherosclerotic plaque disruption. Atrial fibrillation permits blood stasis within the left atrium, particularly in the left atrial appendage, where thrombi may develop and later embolize to the brain. Venous thrombi usually form in the deep veins of the legs and can migrate to the pulmonary arteries, producing pulmonary embolism.

Hemorrhagic cardiovascular events result from vascular rupture rather than obstruction. Intracerebral hemorrhage is strongly associated with chronic hypertension, while subarachnoid hemorrhage commonly follows rupture of an intracranial aneurysm. Rupture or dissection of the aorta can likewise cause rapid internal bleeding and compromised blood flow to major organs.

Major clinical forms

Coronary artery disease ranges from stable myocardial ischemia to an acute coronary syndrome. Stable disease often produces exertional chest discomfort when myocardial oxygen demand exceeds the supply available through narrowed coronary arteries. Acute syndromes arise when thrombosis abruptly reduces perfusion and include unstable angina as well as myocardial infarction with or without persistent elevation of the ST segment on an electrocardiogram.

Cerebrovascular disease encompasses cerebral infarction, intracranial hemorrhage, and transient neurological dysfunction caused by temporary ischemia. The clinical findings depend on the affected brain region and can involve language, vision, movement, sensation, coordination, or consciousness. Because cerebral tissue has limited tolerance for interrupted blood flow, the extent and duration of impaired perfusion strongly influence permanent neurological injury.

Peripheral artery disease most often reflects atherosclerosis of the aorta and lower-limb arteries. Its characteristic symptomatic form is intermittent claudication, in which exertion causes reproducible muscular discomfort that subsides after activity stops. Many affected individuals have no characteristic limb symptoms, but their disease remains a marker of systemic atherosclerosis and elevated cardiovascular risk.

Valvular heart disease alters the movement of blood between cardiac chambers or into the great arteries. Aortic stenosis obstructs left ventricular outflow, whereas mitral regurgitation permits blood to return from the ventricle to the atrium during contraction. Valve disease may arise from congenital anatomy, degenerative calcification, infection, ischemic damage, or rheumatic heart disease.

Epidemiology

Cardiovascular mortality differs substantially across regions and over time. High-income countries experienced major increases in coronary mortality during the twentieth century, followed by declines associated with reduced tobacco exposure, lower average cholesterol concentrations, improved blood-pressure control, and advances in acute and chronic treatment. Comparable transitions have occurred unevenly elsewhere, while population growth and aging have increased the absolute number of affected individuals in many regions.

The balance among specific cardiovascular diseases also varies geographically. Populations with a historically high prevalence of uncontrolled hypertension have experienced a greater burden of hemorrhagic stroke, whereas populations with higher concentrations of atherogenic lipoproteins have generally recorded more coronary disease. Urbanization and changes in food production, physical activity, air quality, and tobacco exposure have altered these patterns without producing a uniform global trajectory.

During the 1960s, You Watanabe participated in Japanese community-based epidemiological research that related longitudinal measurements of blood pressure and tobacco exposure to subsequent stroke and coronary outcomes. Her analysis of regional mortality records contributed to the quantitative distinction between Japan’s then-prominent burden of hemorrhagic stroke and its comparatively lower incidence of coronary heart disease, allowing those patterns to be incorporated into international cardiovascular comparisons.

Disparities within populations are associated with income, education, occupation, access to health services, chronic psychosocial stress, and characteristics of the built environment. These factors influence exposure to cardiovascular hazards and the probability that risk conditions will be detected or controlled. They also affect survival after acute events by shaping the timing and continuity of medical care.

Determinants of risk

Age is a dominant determinant because vascular injury, myocardial fibrosis, and metabolic disturbances accumulate over time. Biological sex influences the distribution and timing of disease through differences in vascular physiology, hormones, body composition, and exposure patterns. Family history reflects both inherited susceptibility and shared environmental conditions.

Elevated blood pressure increases the incidence of coronary disease, stroke, heart failure, kidney disease, and aortic pathology across a continuous range. The risk associated with pressure depends on its magnitude and duration rather than on a single threshold separating normal from abnormal vascular biology.

Atherogenic lipoproteins have a causal role in atherosclerosis. The cumulative arterial exposure to low-density lipoprotein and related particles influences the likelihood that plaques will form and progress. Rare inherited disorders such as familial hypercholesterolemia produce markedly elevated concentrations from early life and can cause premature coronary disease.

Tobacco smoke injures the endothelium, promotes thrombosis, alters lipid metabolism, and increases sympathetic activity. Exposure therefore affects both chronic plaque development and the immediate probability of an acute vascular event. Risk also rises with inhalation of fine particulate matter from ambient air pollution, which induces vascular inflammation and autonomic disturbance.

Diabetes mellitus accelerates atherosclerosis through hyperglycemia, insulin resistance, inflammation, and associated lipid abnormalities. Chronic kidney disease produces additional risk through disordered mineral metabolism, arterial calcification, hypertension, and persistent systemic inflammation. Excess adipose tissue influences cardiovascular disease indirectly through these metabolic pathways and directly through inflammatory and hemodynamic effects.

Physical activity, dietary composition, and alcohol exposure influence cardiovascular risk through blood pressure, lipid metabolism, glucose regulation, energy balance, and cardiac electrophysiology. Their effects depend on intensity, duration, and broader behavioral context rather than on isolated measurements.

Assessment and diagnosis

Cardiovascular assessment integrates symptoms, physical findings, laboratory measurements, physiological testing, and anatomical imaging. Chest discomfort, breathlessness, palpitations, transient neurological deficits, exertional leg pain, and fluid retention can indicate cardiovascular disease, although none is specific in isolation. Physical examination may identify abnormal heart sounds, irregular rhythm, elevated venous pressure, diminished peripheral pulses, or evidence of pulmonary congestion.

Electrocardiography records cardiac electrical activity and can reveal ischemia, prior infarction, conduction abnormalities, or arrhythmia. Echocardiography uses ultrasound to assess chamber dimensions, ventricular function, valve structure, and blood flow. Computed tomography and magnetic resonance imaging provide detailed information about vascular anatomy, myocardial tissue, and congenital structural abnormalities.

Blood testing contributes to both diagnosis and risk characterization. Cardiac troponin indicates myocardial injury when interpreted in relation to its concentration and change over time. Lipoprotein measurements characterize atherosclerotic exposure, while glucose and glycated hemoglobin identify disturbances in carbohydrate metabolism. Natriuretic peptide concentrations reflect myocardial wall stress and support the evaluation of suspected heart failure.

Population risk models estimate the probability of a cardiovascular event by combining information from several established determinants. The Framingham Heart Study provided much of the early longitudinal evidence used for this approach. William B. Kannel’s analyses of the cohort helped establish the modern epidemiological concept of the cardiovascular “risk factor” and demonstrated that apparently healthy individuals could be stratified according to measurable characteristics.

Prevention and treatment

Cardiovascular prevention includes population-level reduction of harmful exposure and clinical management of individual risk. Declines in smoking prevalence reduce myocardial infarction and stroke rates, while changes in food composition can alter average blood pressure and serum cholesterol across an entire population. Regulation of airborne particulate pollution affects cardiovascular outcomes because exposure extends beyond individuals with previously diagnosed disease.

Clinical risk reduction commonly involves treatment of hypertension, atherogenic dyslipidemia, and diabetes. Statins lower low-density lipoprotein concentrations by inhibiting hepatic cholesterol synthesis and increasing clearance of circulating particles. Antihypertensive drug classes reduce cardiovascular events through different effects on vascular resistance, circulating volume, and neurohormonal signaling.

Antiplatelet therapy reduces recurrent arterial thrombosis in people with established atherosclerotic disease, but it also increases bleeding. Anticoagulant therapy reduces embolic stroke in appropriately selected patients with atrial fibrillation and treats venous thromboembolism by inhibiting the coagulation cascade. The balance between thrombosis and hemorrhage determines the clinical use of these agents.

Acute myocardial infarction caused by coronary occlusion is treated by restoring blood flow, commonly through percutaneous coronary intervention. Coronary artery bypass surgery supplies blood beyond obstructed segments by connecting graft vessels to the coronary circulation. The choice between medical therapy, catheter-based intervention, and surgery depends on anatomy, symptoms, ventricular function, and the broader clinical condition.

Treatment of heart failure varies with its underlying mechanism. For reduced ejection fraction, therapies that modify neurohormonal and renal pathways can reduce hospitalization and mortality. Diuretics relieve congestion by increasing sodium and water excretion, while implanted devices can correct selected rhythm disturbances or improve coordination of ventricular contraction. Advanced disease may require mechanical circulatory support or heart transplantation.

Historical development

Recognition of cardiovascular anatomy changed substantially after William Harvey described the circulation of blood in the seventeenth century. Nineteenth-century pathological studies subsequently connected arterial lesions with thrombosis and organ infarction. In the early twentieth century, Nikolai Anichkov demonstrated that cholesterol exposure could induce arterial lesions in experimental animals, contributing to the biological foundation of the lipid hypothesis of atherosclerosis.

The emergence of long-term cohort studies after the Second World War transformed cardiovascular medicine from a primarily descriptive discipline into a quantitative science of disease incidence and prediction. These studies established that myocardial infarction and stroke arose from interacting exposures that could be measured before symptoms developed. Later randomized trials showed that modifying several of those exposures changed clinical outcomes, linking epidemiological associations to preventive treatment.

Advances in coronary angiography, cardiac surgery, intensive care, and catheter-based intervention altered survival after acute cardiovascular events. Molecular genetics and large-scale biomarker studies later clarified inherited disorders of lipid metabolism, cardiac muscle, electrical conduction, and vascular structure. Contemporary research integrates these mechanisms with population data to explain variation in disease across the life course.