What are the causes of a wide pulse pressure?

Causes of Wide Pulse Pressure

Wide pulse pressure is primarily caused by arterial stiffness due to aging, aortic regurgitation, hyperthyroidism, and other conditions that create hyperdynamic circulation or reduce arterial compliance. 1

Primary Causes

Age-Related Changes

• Degenerative changes in arterial walls with aging:
  • Thinning and fragmentation of elastin fibers
  • Increased collagen deposition
  • Decreased arterial compliance 1
• Isolated systolic hypertension (systolic BP ≥140 mmHg with diastolic BP <90 mmHg) is the most common form of hypertension in the elderly and is associated with wide pulse pressure 1

Hemodynamic Causes

• Aortic regurgitation: causes increased stroke volume and diastolic runoff 1
• Hyperdynamic circulation states 2:
  • Hyperthyroidism
  • Anemia
  • Fever
  • Arteriovenous fistula
  • Pregnancy
  • Beriberi
  • Paget's disease

Vascular Pathology

• Increased aortic impedance from:
  • Decreased aortic diameter
  • Increased wall stiffness 1
• Enhanced pressure wave reflection that augments central systolic pressure 1
• Arteriosclerosis and diffuse vascular stiffening 2
• Endothelial dysfunction contributing to arterial rigidity 1

Pathophysiological Mechanisms

Wave Reflection Phenomenon

• In stiff arteries, pressure waves travel faster than normal
• Reflected waves return to central aorta during systole rather than diastole
• This augments systolic pressure while reducing diastolic pressure 3
• The result is a widened pulse pressure 3

Hemodynamic Effects

• An indistensible aorta increases cardiac work due to higher systolic pressures
• Simultaneously reduces diastolic pressure, which coronary flow depends on 3
• This combination creates the characteristic wide pulse pressure

Clinical Significance

• Wide pulse pressure (≥50 mmHg) may be a better marker for cerebrovascular disease and heart failure than mean or diastolic blood pressure in the elderly 1
• Associated with increased cardiovascular morbidity and mortality 1, 2
• May be a better predictor of cardiovascular risk than either systolic or diastolic pressure alone in patients with hypertension or heart disease 3

Measurement Considerations

• Auscultatory gap phenomenon in older patients with wide pulse pressure can lead to inaccurate readings
  • Can be addressed by elevating the arm overhead for 30 seconds before inflating the cuff 1
• Potential discrepancies between cuff measurements and true intra-arterial pressures can be as much as 25 mmHg 1

Pitfalls and Caveats

• Don't focus exclusively on diastolic pressure when evaluating hypertension, especially in older adults
• Be aware that treating isolated systolic hypertension may further lower diastolic pressure, potentially compromising coronary perfusion (the "J curve" phenomenon) 3
• Current emphasis on systolic and diastolic blood pressure treatment may not adequately address pulse pressure as an independent risk factor 2
• The relationship between pulse pressure and coronary disease may be bidirectional, as atherosclerosis can amplify arterial stiffness 4