Correspondence

The Heart in Hypertension

N Engl J Med 1993; 328:212-213January 21, 1993

Article

To the Editor:

Dr. Frohlich and colleagues are to be commended for their excellent review of hypertension and the heart (Oct. 1 issue)1. We would like to elaborate on the references they cited regarding radionuclide scintigraphy in hypertensive patients2,3 and address the issue of the usefulness of thallium imaging in these patients.

One report studied hypertensive patients with severe renal failure who were awaiting renal transplantation2. In that study, 35 percent of the patients had fixed defects of the lateral wall mimicking myocardial infarction. The authors generalized the findings to all hypertensive patients. The duration and severity of hypertension were not described, nor was the correlative coronary arteriographic anatomy. In the other report,3 hypertensive patients without obstructive coronary disease had reversible defects more commonly than fixed defects (Frank MJ: personal communication). This study demonstrated that patients with perfusion defects on thallium imaging have depressed coronary-vasodilator reserve in the absence of obstructive coronary artery disease.

Two additional studies provide further information about thallium imaging in hypertensive patients. In a series of 272 patients undergoing thallium exercise testing, there was an increased incidence of reversible but not fixed defects in hypertensive patients as compared with normotensive patients4. Prisant et al.5 examined 92 hypertensive patients undergoing thallium exercise testing and coronary angiography. They found that a normal scan virtually excluded serious coronary disease (negative predictive value, 98 percent) and a positive scan identified nearly all patients with coronary artery disease (sensitivity, 94 percent), although false positive scans were frequently noted (specificity, 64 percent).

Thus, myocardial perfusion imaging remains valuable in the evaluation of patients with hypertension and suspected coronary artery disease. Normal studies are frequently observed and effectively rule out obstructive coronary artery disease. Fixed defects are found no more frequently in hypertensive patients than normotensive patients. Reversible defects are due to epicardial coronary artery disease or depressed coronary flow reserve. Ultimately, the diagnosis of coronary artery disease in hypertensive patients with reversible defects may require coronary arteriography.

Michael P. Cecil, M.D.
William A. Fajman, M.D.
Emory University School of Medicine, Atlanta, GA 30322

Jack A. Ziffer, M.D.
Baptist Hospital of Miami, Miami, FL 33176

5 References

1. 1

   Frohlich ED, Apstein C, Chobanian AV, et al. The heart in hypertension. N Engl J Med 1992;327:998-1008
   Full Text | Web of Science | Medline

2. 2

   DePuey EG, Guertler-Krawczynska E, Perkins JV, Robbins WL, Whelchel JD, Clements SD. Alterations in myocardial thallium-201 distribution in patients with chronic systemic hypertension undergoing single-photon emission computed tomography. Am J Cardiol 1988;62:234-238
   CrossRef | Web of Science | Medline

3. 3

   Houghton JL, Frank MJ, Carr AA, von Dohlen TW, Prisant LM. Relations among impaired coronary flow reserve, left ventricular hypertrophy and thallium perfusion defects in hypertensive patients without obstructive coronary artery disease. J Am Coll Cardiol 1990;15:43-51
   CrossRef | Web of Science | Medline

4. 4

   Schulman DS, Francis CK, Black HR, Wackers FJT. Thallium-201 stress imaging in hypertensive patients. Hypertension 1987;10:16-21
   Web of Science | Medline

5. 5

   Prisant LM, von Dohlen TW, Houghton JL, Carr AA, Frank MJ. A negative thallium (±dipyridamole) stress test excludes significant obstructive epicardial coronary artery disease in hypertensive patients. Am J Hypertens 1992;5:71-75
   Web of Science | Medline

Author/Editor Response

Dr. Frohlich replies:

To the Editor: My colleagues and I agree with Dr. Cecil et al. that in hypertensive patients, coronary arterial insufficiency may occur as a consequence of increased coronary arterial resistance, including diminished coronary flow and flow reserve, and altered blood rheology. These changes in the coronary circulation are independent of occlusive atherosclerotic epicardial arterial disease. Space restrictions did not permit a review of the reports on the use of scintigraphy in assessing patients with hypertensive heart disease for the presence of diminished coronary flow and flow reserve. We did, however, refer to the pioneering work in this area by Marcus and his associates,1 and we take much satisfaction in the recent burgeoning of studies (cited by Cecil et al.) of patients with hypertensive heart disease. Indeed, as we emphasized, this concept was one of the major factors that stimulated us to write this review, to dissociate hypertensive heart disease from the complication of coronary atherosclerosis. We have no doubt that diminished coronary flow and flow reserve, increased coronary vascular resistance and blood viscosity in hypertension, and the increased myocardial oxygen demand engendered by the elevated arterial pressure and increased cardiac mass all play a major part in the high prevalence of sudden death and silent ischemia associated with hypertension.

However, our working group made no position statement on the need for myocardial scintigraphy in patients with hypertension, although the value of the technique was explicitly stated. At present, the decision to perform resting and exercise (or pharmacologic) provocative tests of coronary flow should be individualized. At this time, when costs are a major consideration in patient care, the indications for these studies must also be determined on an individual basis.

Edward D. Frohlich, M.D.
Alton Ochsner Medical Foundation, New Orleans, LA 70121

1 References

1. 1

   Marcus ML, Koyanagi S, Harrison DG, Doty DB, Hiratzka LF, Eastham CL. Abnormalities in the coronary circulation that occur as a consequence of cardiac hypertrophy. Am J Med 1983;75:Suppl 3A:62-66
   CrossRef | Web of Science | Medline