Sustained reduction of exercise perfusion defect extent and severity with isosorbide mononitrate (Imdur) as demonstrated by means of technetium 99m sestamibi.
BACKGROUND
The impact of long-acting nitrates on the extent and severity of stress-induced myocardial ischemia is not well described, especially after long-term treatment.


METHODS
Forty patients with chronic stable angina and reversible ischemia on an exercise stress myocardial perfusion single photon emission computed tomography (ex-SPECT) were prospectively studied in a 6-week period. At baseline, rest thallium-201/exercise stress technetium 99m sestamibi SPECT was performed, followed by treatment with extended-release isosorbide 5-mononitrate (5-ISMN, Imdur). Follow-up ex-SPECT was performed 5 days and 6 weeks after the initiation of therapy with extended-release 5-ISMN. The exercise treadmill testing (ETT) protocol and exercise duration of the follow-up studies were the same as that of the baseline ETT. Defect extent and severity were analyzed both by means of an automated quantitative method, with CEqual software, and visually, with a 20-segment scoring system (which was also used to derive a summed stress score [SSS]).


RESULTS
In the 6-week study period, significant reductions occurred in both the extent and the severity of exercise-induced ischemia by means of quantitative SPECT (13.8% [P<.0003] and 12.7% [P<.0003], respectively). There was no significant change in these variables between stages 2 (day 5) and 3 (6 weeks), indicating no development of tolerance to the nitrate effect. Similar reductions were noted by means of the visual analysis (SSS reduction of 13.0% [P<.002]) in the entire study period.


CONCLUSIONS
Patients with chronic-stable-angina treated with a long-acting nitrate demonstrate improvement in myocardial perfusion defect extent and severity in an extended period by means of both visual and quantitative analysis of sequential exercise testing to the same rate-pressure product end point.
Lewin
H C
HC
Department of Imaging, Cedars-Sinai Medical Center, The CSMC Burns and Allen Research Institute, University of California Los Angeles, USA.
Hachamovitch
R
R
Harris
A G
AG
Williams
C
C
Schmidt
J
J
Harris
M
M
Van Train
K
K
Siligan
G
G
Berman
D S
DS
D000368:Aged; D000787:Angina Pectoris / Q000000981:diagnostic imaging* / Q000188:drug therapy; D003326:Coronary Circulation; D003692:Delayed-Action Preparations; D005080:Exercise Test; D005260:Female; D006801:Humans; D007548:Isosorbide Dinitrate / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D008297:Male; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents / Q000627:therapeutic use*
D003692:Delayed-Action Preparations; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D014665:Vasodilator Agents; D017256:Technetium Tc 99m Sestamibi; D007548:Isosorbide Dinitrate; C030397:isosorbide-5-mononitrate