Biomedical subjects

RM Fleming

Publications and source records attributed to RM Fleming.

At least 19 recordsLinked to original sources

PubMed2000

The Clinical Importance of Risk Factor Modification: Looking at Both Myocardial Viability (MV) and Myocardial Perfusion Imaging (MPI).

Determination of changes in coronary artery disease (CAD) following risk factor modification (lipid lowering and stress reduction) have focused only on changes in myocardial blood flow (Q)/myocardial perfusion imaging (MPI) and not myocardial viability (MV). To determine the outcome of each and to determine if there are differences in myocardial viability versus coronary blood flow, 31 people were studied for 1 year with comparison of baseline and 1-year PET results. One subject underwent an additional 2-year follow-up study, providing a total of 32 comparisons. A total of 224 myocardial segments were compared with improvement in MPI seen in 58 of 224 segments (25.9%), stabilization in 111 of 224 (49.6%) segments, and progression of disease in 55 of 224 (24.6%) segments. MV improved in 82 of 224 segments (36.6%), showed stabilization in 83 of 224 (37.0%) of the segments, and worsening in 59 (26.3%) of 224 segments. When improvement in either MPI or MV were added together, improvement was seen in 50.9% (p </= 0.001) of the segments and stabilization was seen in 30.4% (p </= 0.001). Despite RFM as defined above, progression of CAD and loss of myocardial viability was noted in 15% of the myocardial segments studied. This study demonstrated that regardless of whether one looks at MPI alone or a combination of MPI and MV, reduction of serum lipids and stress reduction alone cannot guarantee stabilization or regression of atherosclerosis. Clearly there are additional factors involved which play an important role in reveral of CAD which must be addressed in future studies.

Journal Article↗

PubMed2000

The Natural Progression of Atherosclerosis in an Untreated Patient With Hyperlipidemia: Assessment via Cardiac PET.

Recent studies have demonstrated successful reversibility of atherosclerosis in 1/3 of the cases, stabilization in 1/3, and continued progression in the remaining 1/3 of individuals treated for hypercholesterolemia and stress reduction. However, no reported data exist about the natural progression of untreated coronary artery disease in the clinical setting with which these results can be compared. In this case report, we will review the natural progression of atherosclerosis as documented by positron emission tomography (PET) imaging during a 104-day period.

Journal Article↗

PubMed1999

Comparing a High-dose Dipyridamole SPECT Imaging Protocol with Dobutamine and Exercise Stress Testing Protocols. Part III: Using Dobutamine to Determine Lung-to-Heart Ratios, Left Ventricular Dysfunction, and a Potential Viability Marker.

Determination of the severity of coronary artery disease (CAD) by single photon emission computed tomography (SPECT) imaging has previously been shown to have greater sensitivity, specificity, and accuracy when performed with pharmacologic stress using dobutamine than by standard dose dipyridamole (SDD) or exercise stress testing (EST) prior to SPECT imaging. The use of lung to heart (L:H) ratios has been shown to be valuable in determining the presence or absence of left main (LM) or triple vessel (3V) CAD. No such work has been previously reported for dobutamine. Twenty-one patients were studied using dobutamine (n = 7) or EST (n = 14). These results were compared with results from Part II of this series of studies using high-dose dipyridamole (HDD) pharmacologic stress. In this study, patients underwent L:H ratio analysis following injection of 3 mCi of Tl-201, this provides sufficient time for thallium clearance from the blood pool. Results of the L:H ratios were compared with the results of coronary arteriographic (CA) evaluation. Patients who were "stressed" via EST demonstrated statistically greater (p </= 0.001) L:H ratios in patients with LM/3V CAD when compared with patients who had 0-2 significantly stenosed coronary arteries. Patients stressed with dobutamine demonstrated lower L:H ratios (p = NS) in patients with LM/3V CAD than was seen for patients with 0-2 V CAD. Patients stressed with dobutamine had statistically (p </= 0.05) lower L:H ratios than did similar patients stressed with EST. Increased L:H ratios following EST and HDD, as shown previously in Part II of this series, provide excellent markers for LM/3V CAD following Tl-201 injection. The presence of "normal" L:H ratios in patients with LM/3V CAD following dobutamine stress may suggest the presence of "stunned" or "hibernating" myocardium. The presence of "decreased" L:H ratios following dobutamine after HDD or EST has already shown an increased L:H ratio, might suggest a marker for myocardial viability that deserves further investigation.

Journal Article↗

PubMed1998

Comparing a High-Dose Dipyridamole SPECT Imaging Protocol with Dobutamine and Exercise Stress Testing Protocols. Part II: Using High-Dose Dipyridamole to Determine Lung-to-Heart Ratios.

Determination of the severity of coronary artery disease (CAD) by single photon emission computed tomography (SPECT) imaging has previously been shown to have greater sensitivity, specificity, and accuracy when performed with pharmacologic stress using high-dose dipyridamole (HDD), than by standard dose dipyridamole (SDD) or exercise stress (EST) prior to SPECT imaging. The use of lung-to-heart (L:H) ratios has been shown to be valuable in determining the presence or absence of left main (LM) or triple vessel (3V) CAD. Fifty-four patients were studied; HDD (n = 40) or EST (n = 14) was used for the study. These patients underwent L:H ratio analysis, in which anterior views were used 5-10 minutes after the injection of 3 mCi of T1-201. Results of the L:H ratios were compared with the diagnosis of epicardial CAD, as determined by coronary (CA) arteriography. Patients who were "stressed" using either HDD or EST demonstrated statistically greater (p < 0.001) L:H ratios if they had LM/3V CAD when compared with patients who had 0-2 significantly stenosed coronary arteries. Though L:H ratios were greater when HDD pharmacologic stress was used, there was no statistical (p = NS) differences between the two groups. Increased L:H ratios with HDD and EST provide excellent markers for LM/3V CAD using T1-201 imaging. Coupled with previously reported SPECT data, the use of HDD shows promise for increasing the diagnostic accuracy of SPECT imaging.

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PubMed1995