What is Hypertension (HTN)?

What is Hypertension (HTN)?

Hypertension is a chronic medical condition defined as persistently elevated blood pressure ≥130/80 mmHg, representing a continuous cardiovascular risk factor that directly increases morbidity and mortality through damage to multiple organ systems. 1

Definition and Diagnostic Thresholds

Current diagnostic criteria define hypertension as systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥80 mmHg, based on the most recent American College of Cardiology/American Heart Association consensus. 1 This represents a lowering from the older JNC-7 threshold of 140/90 mmHg, which means an additional 31 million Americans now meet criteria for hypertension. 1

• Elevated blood pressure (pre-hypertension) is defined as systolic 120-129 mmHg with diastolic <80 mmHg 1
• Blood pressure exists on a continuous spectrum of risk, with cardiovascular events increasing linearly from systolic pressures as low as 110 mmHg 1
• The diagnosis requires confirmation with multiple readings on separate occasions, not a single elevated measurement 1

Pathophysiology and Disease Mechanisms

Hypertension fundamentally represents a nutritional-hygienic disease driven by chronic caloric excess, supraphysiological sodium intake, excessive alcohol consumption, and psychosocial stressors. 1 The underlying mechanisms are multifactorial:

• Endothelial dysfunction and vascular remodeling alter arterial compliance and resistance 2
• Sympathetic nervous system activation increases cardiac output and peripheral vasoconstriction 3
• Renin-angiotensin-aldosterone system dysregulation promotes sodium retention and vasoconstriction 3
• Sodium dysregulation leads to volume expansion and increased cardiac workload 3

Target Organ Damage and Clinical Consequences

Hypertension is a common cardiovascular risk factor leading to heart failure, coronary artery disease, stroke, peripheral artery disease, and chronic renal failure. 1 The disease causes progressive damage through sustained pressure overload:

Cardiac Complications

• Left ventricular hypertrophy (LVH) develops as an adaptive response to increased afterload 1
• Heart failure occurs in both reduced and preserved ejection fraction phenotypes 1
• Coronary artery disease progresses through accelerated atherosclerosis 4
• Cardiac arrhythmias, most commonly atrial fibrillation, result from structural remodeling 1

Cerebrovascular Complications

• Stroke risk increases exponentially with blood pressure elevation 1
• Hypertensive encephalopathy manifests with seizures, lethargy, cortical blindness, and coma when autoregulation fails 1
• Vascular dementia develops from chronic cerebral hypoperfusion 1

Renal Complications

• Chronic kidney disease develops from glomerular hyperfiltration and sclerosis 1, 3
• End-stage renal disease occurs particularly in African American males 4
• Proteinuria indicates established nephropathy requiring aggressive blood pressure control 1

Vascular Complications

• Hypertensive retinopathy with flame-shaped hemorrhages, cotton wool spots, and papilledema indicates malignant hypertension 1
• Aortic dissection and aneurysms result from chronic wall stress 4
• Peripheral vascular disease causes claudication and limb ischemia 1

Epidemiology and Population Impact

Hypertension affects approximately 30-40% of the adult population worldwide, making it the leading factor in the global burden of disease. 5 In the United States specifically:

• 72 million adults (1 in 3) meet traditional criteria for hypertension 1
• By the eighth decade of life, over 75% have elevated blood pressure, predominantly systolic 1
• Up to 33% of men aged 20-44 years with hypertension are undiagnosed due to the asymptomatic nature of the disease 1
• Only 50% of hypertensive individuals achieve adequate blood pressure control with treatment 1

High-Risk Populations

African American persons develop hypertension at younger ages and present with higher prevalence of complications including stroke and end-stage kidney disease compared to other ethnic groups. 1 This population requires particularly vigilant screening and aggressive management.

Clinical Presentation and Detection

Hypertension is characteristically asymptomatic, which creates challenges for detection and treatment adherence. 1 This silent nature means:

• Routine screening is essential for diagnosis, with blood pressure measurement recommended at every clinical visit or at least every 6 months 1
• Patients often present only after target organ damage has occurred 1
• Undiagnosed hypertension represents a major public health concern, particularly in younger populations 1

Common Clinical Pitfalls

Accurate blood pressure measurement is imperative regardless of treatment targets. 1 Key considerations include:

• White-coat hypertension (elevated office readings with normal ambulatory pressures) and masked hypertension (normal office readings with elevated ambulatory pressures) are common phenomena that require out-of-office monitoring for proper diagnosis 1
• In-office measurements may inadequately reflect true blood pressure status 1
• Home and ambulatory blood pressure monitoring provide crucial supplementary data 1