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Effect of hypertension and hypertrophy on coronary microvascular pressure

M Fujii1, D W Nuno, K G Lamping

  • 1Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City 52242.

Circulation Research
|July 1, 1992
PubMed

Insights

Hypertension and left ventricular hypertrophy increase coronary microvascular pressure differences. This heightened transmural resistance in the endocardium may increase the risk of subendocardial ischemia in these patients.

Area of Science:

  • Cardiovascular Physiology
  • Renal Hypertension Research

Background:

  • Coronary microvascular pressure transmural differences are crucial for myocardial perfusion.
  • Hypertension and left ventricular hypertrophy are known risk factors for cardiovascular disease.

Purpose of the Study:

  • To investigate if transmural differences in coronary microvascular pressures are amplified in the presence of hypertension and left ventricular hypertrophy.
  • To determine the impact of hypertension and hypertrophy on coronary microvascular resistance.

Main Methods:

  • Isolated, arrested canine hearts underwent adenosine vasodilation.
  • Epicardial and endocardial microvascular pressures were measured at varying left main coronary perfusion pressures (60-100 mm Hg).
  • Comparisons were made between normotensive and hypertensive (one-clip, one-kidney) groups.

Main Results:

  • Endocardial microvascular pressures were consistently lower than epicardial pressures across all perfusion levels in both groups.
  • Epicardial arteriole pressures, as a percentage of perfusion pressure, were similar between normotensive and hypertensive hearts.
  • Endocardial pressures at 90 and 100 mm Hg perfusion were significantly lower in hypertensive, hypertrophied hearts compared to controls.

Conclusions:

  • Hearts with hypertension and hypertrophy exhibit greater transmural resistance to microvascular perfusion.
  • Altered vascular anatomy secondary to hypertension and hypertrophy likely contributes to this resistance.
  • Increased endocardial resistance may predispose to subendocardial ischemia in hypertensive, hypertrophied hearts.

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