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We read with interest the report by Pini et al. (1)that stated patients with isolated systolic hypertension had a higher prevalence of cardiac hypertrophy and carotid atherosclerosis than did those with diastolic hypertension. Indeed, hypertensive left ventricular hypertrophy is the most evident manifestation of hypertensive target organ damage, and such patients are at particularly high risk for strokes and heart attacks. We would like to propose an additional interpretation of their important observations.
Despite the vessels being exposed to high pressures, the main complications of hypertension (strokes, myocardial infarction) are, paradoxically, thrombotic rather than hemorrhagic — the so-called thrombotic paradox of hypertension or the Birmingham paradox (2). The findings by Pini et al. (1)would actually strengthen our view that hypertension confers a prothrombotic or hypercoagulable state by fulfilling the three different components of Virchow’s triad for thrombogenesis. With regard to the latter, there ought to be changes in the blood flow, changes in the vessel wall, and changes in the blood constituents, for increased thrombogenesis. “Abnormal flow” is evident in hypertension, with blood vessels exposed to blood flow under high pressures, as well as abnormal coronary flow reserve and microcirculatory changes (3). We had previously reported abnormalities in prothrombotic factors, endothelial function, and platelet activation in patients with isolated systolic hypertension, comparable to that observed with systolic–diastolic hypertension (3–5).
The study by Pini et al. (1)certainly confirms the presence of “vessel wall abnormalities” with the high prevalence of cardiac hypertrophy and carotid atherosclerosis. Furthermore, hypertensive patients with target organ damage (5)show evidence suggestive of an even greater prothrombotic state, which would contribute to the high risk of vascular complications in such patients.
- American College of Cardiology Foundation