Usefulness of concomitant nitrate administration for the enhancement of viability detection with myocardial perfusion imaging.

Myocardial viability assessment is crucial in the evaluation of patients who had prior myocardial infarction for revascularisation procedures. Conventional methods include nuclear myocardial perfusion imaging, dobutamine stress echocardiography and positron emission tomography. Utility of nitrate in assessment of viability was assessed. Twenty-five patients with prior myocardial infarction underwent 99mTc-sestamibi single photon emission computed tomography protocol of stress, rest and post 5 mg sublingual isorbide dinitrate. The mean age of the patients was 51.28 years. Eight (32%) had reduction in perfusion defect and increased tracer uptake following nitrate administration. It is concluded that addition of nitrate adds to utility of conventional perfusion imaging in the assessment of myocardial viability.

Comparison of gastric mucosal blood flow in normal subjects and in patients with portal hypertension using endoscopic laser-Doppler velocimetry.

OBJECTIVE: To compare gastric mucosal blood flow (GMBF) in normal subjects with that in patients with portal hypertension with or without portal hypertensive gastropathy (PHG). METHODS: GMBF was measured by endoscopic laser-Doppler velocimetry in 20 gastroscopically normal subjects and 30 patients with portal hypertension with or without PHG. The effects of breath-holding (vasomotor reflex), submucosal epinephrine and sublingual isosorbide dinitrate were also studied. RESULTS: In normal subjects, GMBF on the greater curvature was (mean +/- SD) 9.5 +/- 1.3 V and on the lesser curvature, 9.1 +/- 1.9 V. Breath-holding caused a reduction in GMBF by 57.1 +/- 13.7%, submucosal epinephrine reduced it by 41.5 +/- 21.5% and sublingual isosorbide caused a rise of 25.8 +/- 15.2%. The GMBF on the greater and lesser curvature respectively in patients with mild PHG (7.7 +/- 1.2 V and 7.7 +/- 0.8 V) and those with severe PHG (6.5 +/- 3.5 V and 6.3 +/- 2.2 V), was significantly less than that in normal subjects (p < 0.05 and p < 0.001 respectively). Vasomotor reflex was blunted in patients with mild and severe PHG (23.3% +/- 20.3 and 23.1% +/- 17.7 respectively, p < 0.001). Responses to submucosal epinephrine and sublingual isosorbide were similar to those recorded in normal subjects. CONCLUSIONS: Patients with portal hypertension have significantly reduced GMBF and significantly attenuated vasomotor reflex in the gastric vascular bed as compared to normal subjects.