Showing papers by "Ochsner Medical Center published in 1997"

Effects of cardiac rehabilitation and exercise programs on exercise capacity, coronary risk factors, behavior, and quality of life in patients with coronary artery disease

Abstract: Previous studies have indicated the benefits of cardiac rehabilitation programs after major coronary artery disease (CAD) events. We studied 591 consecutive patients from two academic institutions before and after completion of a cardiac rehabilitation and exercise training program to determine the effects of this therapy on exercise capacity, indices of obesity, plasma lipid values, behavioral characteristics, and quality of life parameters. After cardiac rehabilitation, statistically significant improvements occurred in exercise capacity (+33%), percent body fat (-6%), body mass index (-1%), HDL-C (+5%), triglycerides (-9%), LDL-C/HDL-C (-6%), anxiety score (-39%), depression score (-35%), somatization score (-37%), and in all parameters of quality of life studied (total +14%). These data further support the ability of cardiac rehabilitation and exercise training programs to improve exercise capacity, plasma lipid values, obesity indices, behavioral characteristics, and quality of life parameters in a large cohort of patients who have had major CAD events.

Prognostic Value of Specific KRAS Mutations in Lung Adenocarcinomas

Abstract: Adenocarcinomas of the lung remain a significant public health problem. Locally defined (stage I) tumors are considered amenable to resection with curative intent. However, only about 45% of these patients survive for 5 years. The median survival for more advanced tumors is drastically lower. Much research has been focused on identifying a valid genetic biomarker of prognosis. Mutations of the proto-oncogene KRAS have been identified by some groups as being a valid prognostic indicator for adenocarcinoma of the lung. To evaluate the effect of KRAS gene mutation on the survival of patients with lung adenocarcinoma, 181 archival tumors were examined by PCR and denaturing gradient gel electrophoresis. Mutations in either codon 12 or 13 were found in 31.5% of the samples. The most common mutation was a G-->T transversion in codon 12, representing 66.7% of the mutations. No difference was observed in the survival of patients with a KRAS mutation versus those whose tumors contained wild-type KRAS. This lack of difference was also observed when the analysis was restricted to those with stage I tumors or when patients with stage I or II disease were grouped together. However, certain amino acid substitutions, including cysteine, arginine, and aspartate, indicated a significantly poorer prognosis, whereas hydrophobic amino acid substitutions showed a significantly better prognosis than wild-type (P = 0.04). Sample sizes were small for this analysis due to the number of possible mutations. As expected, the stage of tumor at resection was the most significant predictor of outcome. Based on this study of 181 patients from two major medical centers located in different cities, we conclude that KRAS mutation status is not a satisfactory predictor of prognosis in lung adenocarcinoma, but the substitution of a polar or charged amino acid for the wild-type glycine residue may be a negative prognostic indicator.

A controlled study of the effects of mental relaxation on autonomic excitatory responses in healthy subjects

Abstract: OBJECTIVE: Circumstantial evidence indicates that, in the presence of a suitable substratum, sudden, behaviorally induced increases in sympathetic drive to the cardiovascular system might play an important physiopathological role in various conditions, ranging from arterial hypertension to sudden coronary death. Accordingly, it might be useful to study the effects of behavioral interventions, such as mental relaxation, that might be capable of blunting excitatory autonomic responses. It would also be preferable to study healthy subjects in whom autonomic control is not modified by the presence of disease, and to use noninvasive approaches to minimize the possible emotional impact produced by invasive recordings. METHODS: We examined healthy subjects who were either subjected to relaxation training (N = 13) or sham relaxation (N = 12). An additional group, treated with beta-adrenergic blockade (N = 12), was also examined. Spectral and cross-spectral analysis of RR interval and systolic arterial pressure (SAP) variabilities provided quantitative markers of sympathovagal balance modulating the sinoatrial (SA) node, of sympathetic vasomotor modulation, and of the gain of the arterial pressure/heart period baroreflex (index alpha). Subjects were studied at rest, during standing, and during mental arithmetic. RESULTS: Data indicate that both beta-adrenergic blockade and relaxation training significantly blunted the excitatory autonomic responses to standing and to mental arithmetic. Indices of sympathetic modulation also seemed reduced by beta blockade at rest. No changes were observed with sham training. CONCLUSIONS: Frequency domain analysis of cardiovascular variabilities, using a totally noninvasive approach, indicates that relaxation training significantly blunts the excitatory autonomic changes produced by standardized behavioral laboratory stimuli.

Cyclosporine-induced hypertension: Evidence for maintained baroreflex circulatory control

Abstract: Background: The clinical use of cyclosporine as an immunosuppressive agent enhanced long-term survival in transplant recipients at the expense of a high incidence of induced hypertension. Altered neurovegetative (autonomic) cardiovascular control is suspected as a mechanism of this form of hypertension. Methods: Spectral analysis of systolic arterial pressure and R-R interval variability (electrocardiographic recordings) were performed, and the index a of baroreflex gain was computed in four groups of subjects matched for age: 13 orthotopic heart transplant recipients; 13 solid organ transplant recipients; 13 patients with essential hypertension; and 18 control subjects with normal blood pressure. All but the control subjects were treated with similar dihydropyridine calcium entry blockers. Heart and solid organ transplant recipients also received cyclosporine. Results: R-R variance was lowest in the heart transplant recipients. The spectral profile of R-R interval was suggestive of sympathetic predominance in the patients withhypertension, but not in the solid organ transplant recipients or the control subjects. Systolic blood pressure variability and low frequency component (a marker of sympathetic vasomotor modulation) were similar in the four groups. The index a was 1.8 ± 2.2 in heart transplant recipients, 11.7 ± 6.6 in solid organ transplant recipients, 7.3 ± 3.6 in patients with hypertension, and 13.5 ± 6.4 msec/mm Hg in control subjects (p = 0.0001). Conclusions: These data indicate that (1) cyclosporine-induced hypertension in heart transplant recipients is associated with a loss of baroreflex function as a result of cardiac denervation-related uncoupling; (2) compared with patients with hypertension, organ transplant recipients with hypertension demonstrated a maintained baroreflex function as indicated by a lack of reduction of the index α; (3) baroreflex heart rate control in dihydropyridine-treated cyclosporine-induced hypertension is well maintained.

Identification of Perfusion Abnormalities Using FSO69, a Novel Contrast Agent, in Conscious Dogs.

Abstract: Recent advances in the production of echocardiographic contrast agents has resulted in the ability to delineate areas of hypoperfusion after coronary occlusions and stenoses following their intravenous injection. Most of these studies though have been done in open chest animals. This study was done to determine if we could assess myocardial perfusion following the intravenous administration of FSO69, a suspension of perfluoropropane filled albumin microspheres (3.6 µm average microbubble size, concentration 8 x 10(8)), in spontaneously breathing closed chest dogs. Twenty-seven mongrel dogs were instrumented on day 1. The chest was then closed and the dogs were restudied 3-7 days later, while spontaneously breathing. Homogeneous perfusion was observed in most dogs by all three independent and blinded observers. Perfusion abnormalities were likewise identified in most instances by all blinded reviewers on interventions designed to decrease regional blood flow. A good correlation between perfusion defect size between investigators was observed. In summary, our data suggest that FSO69 can be used to assess regional myocardial perfusion in spontaneously breathing dogs. These results support its use in humans.