Biomedical subjects

John C Giacomini

Publications and source records attributed to John C Giacomini.

7 recordsLinked to original sources

PubMed2005

Abnormal cardiovascular response to exercise in patients with peripheral arterial disease: Implications for management.

Exercise is beneficial in improving claudication and functional capacity in patients with peripheral arterial disease (PAD). However, the physiologic response during and after exercise testing in this patient population has not been fully described. This study examined the cardiovascular response to exercise and explored the potential contribution of vascular noncompliance to exercise-induced hypertension in 124 patients with PAD and claudication and 31 comparison (C) patients with PAD with no walking limitations. Maximal walking distance was determined by an exercise treadmill test. Heart rate and blood pressure were monitored before, during, and immediately after an exercise test. Vascular compliance of the small and large vessels was measured using pulse waveform analysis. Individuals with low supine resting heart rate had longer pain-free walking distance (r = -0.195, P = .019) and maximal walking versus the C group (62 beats/min, standard deviation [SD] = 10, P = .02). Systolic blood pressure during supine rest was significantly lower for the PAD group (mean = 141 mm Hg, +/- SD = 22) versus the C group (mean = 153 mm Hg, +/- SD = 20, P = .003). Vascular compliance of large vessels was higher in the C group (mean = 4.13 +/- 4.13 mL/mm Hg x 100) compared with the PAD group (mean = 2.95 +/- 1.6 mL/mm Hg x 100). This study describes the exaggerated exercise cardiovascular response and impaired vascular compliance in patients with PAD. These results provide further evidence supporting the importance of a monitored treadmill exercise test before initiation of an exercise program to ensure safe and accurate exercise recommendations, and to identify individuals that require more intensive pharmacotherapy to prevent exercise-induced hypertension and tachycardia.

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PubMed2005

Statin therapy in heart failure.

PURPOSE OF REVIEW: The 3-hydroxy-3-methylglutaryl-coenzyme-A reductase inhibitors, or statins, have been shown to reduce cardiovascular morbidity and mortality among a wide spectrum of patients with established atherosclerotic vascular disease. Mounting experimental and clinical evidence also suggest a potential benefit as well as theoretical harm of statin therapy in patients with heart failure. RECENT FINDINGS: This article briefly summarizes the therapeutic properties of statins that may be of benefit to patients with heart failure and the theoretical adverse effects of cholesterol reduction in this group of patients. A number of nonrandomized clinical studies over the past several years have shown an association between statin use and reduced overall mortality. Several large-scale randomized studies designed to confirm these findings are currently under way. SUMMARY: Statin therapy appears to improve clinical outcomes in patients with both ischemic and nonischemic cardiomyopathy independently of their cholesterol-lowering properties. The theoretical adverse properties of statins in heart failure patients have not been substantiated in small to medium-sized clinical trials. Although the encouraging results of these preliminary studies suggest a role for statin therapy in heart failure, larger studies are needed to validate these findings. Several ongoing randomized trials are currently under way to evaluate the effect of statin therapy on cardiovascular outcomes in heart failure patients. The results of these studies, expected in the next several years, should provide scientific evidence for the role of statins in the treatment of failure.

Cardiac Output, Low↗

PubMed2005

Suboptimal intensity of risk factor modification in PAD.

This study extends earlier trials indicating that atherosclerosis risk factors are underdetected and undertreated in peripheral arterial disease (PAD) patients. Recognition and treatment of hyperlipidemia and hypertension in PAD patients is suboptimal. Diabetes appears to be detected more frequently although glycemic control is still suboptimal. The use of antiplatelet therapy is particularly underutilized. Additionally, despite the demonstrated efficacy of regular exercise in PAD patients, almost half of the study sample was sedentary. Approximately one third of the current study sample was overweight and nearly one third was obese by ATP-III guidelines. Only 31% of subjects were taking dietary measures to improve their cardiovascular health, and even fewer were physically active. To rectify suboptimal management of risk factors, there is a need for increased public awareness of PAD, reimbursement and implementation of screening programs and more aggressive treatment. Future studies are needed to examine innovative interventions for identification and management of cardiovascular risk factors in patients with PAD.

Age Distribution↗

PubMed2005

A pilot study of L-arginine supplementation on functional capacity in peripheral arterial disease.

Peripheral arterial disease (PAD) impairs walking capacity and is often associated with a profound endothelial vasodilator dysfunction, characterized by reduced bioactivity and/or synthesis of endothelium-derived nitric oxide (NO). Previous studies have suggested that dietary supplementation of L-arginine, the precursor of NO, improves endothelium-dependent vasodilation, limb blood flow and walking distance. However, these studies have been small, and have used large intravenous doses of L-arginine. The optimal dose of L-arginine has not been determined. Accordingly, this pilot study was conducted to establish the lowest effective oral dose of L-arginine to improve walking distance in preparation for the definitive study. Patients with PAD and intermittent claudication (n = 80) participated in this study. Eligibility criteria included: (1) ankle-brachial index (ABI) at rest < or = 0.90; (2) post-exercise reduction in ABI > or = 25%; and (3) difference in absolute claudication distance of < or = 25% between two consecutive treadmill tests. Treadmill testing was performed using the Skinner-Gardner protocol and community-based walking was assessed using the walking impairment questionnaire. Patients were randomly assigned to oral doses of 0, 3, 6 or 9 g of L-arginine daily in three divided doses for 12 weeks. Treadmill testing was performed prior to administration of the study drug and again after 12 weeks of treatment. The study drug was well tolerated, with no significant adverse effects of L-arginine therapy. The safety laboratory studies were unremarkable, except for a statistically significant reduction in hematocrit in the L-arginine-treated groups. There was no significant difference observed in absolute claudication distance between the groups. However, a trend was observed for a greater increase in walking distance in the group treated with 3 g L-arginine daily, and there was a trend for an improvement in walking speed in patients treated with L-arginine. This pilot study provided data for safety, for power calculation and for dosing for the larger definitive trial that is now underway.

Administration, Oral↗

PubMed2004

Exercise patterns and cardiovascular fitness of patients with peripheral arterial disease.

Peripheral arterial disease (PAD) is characterized by walking impairment as the result of claudication, which is improved by exercise. Few studies have examined the impact of existing exercise patterns in community-dwelling patients with PAD on cardiovascular fitness and absolute claudication distance (ACD). This descriptive study examines exercise patterns, walking distance, and cardiovascular fitness in a sample of community-dwelling older adults with PAD. Approximately 50% of subjects reported walking 4 (+/-2) days per week for 38 +/- 24 minutes. ACD (exercisers = 459.9 +/- 272; non-exercisers = 351.2 +/- 266.3, P = .06) and initial claudication distance (exercisers = 198.5 +/- 139.7; non-exercisers = 138.7 +/- 95.8 P = .02) were similar between groups. The workload accomplished was approximately 4.1-4.7 metabolic equivalents. Resting heart rate (HR) was associated with initial claudication distance ( r = -.37, P = .001) and ACD ( r = -.46, P < .01) and was lower in the group of exercisers versus the non-exercisers ( P = .05). Mean resting SBP was elevated and continued to increase at peak exercise with no difference between groups ( P = .75). Quality of life was poor for both groups. Simultaneous multiple regression analysis was performed to determine predictors of peak exercise HR. The model included gender, age, current exercise, ankle-brachial index, coronary artery disease, beta blockers, ACD, and atrial fibrillation (R = 44%, P = .01). Higher peak exercise HR was associated with older age, female gender, no beta blockers, and greater ACD ( P < .01). The findings from this descriptive study demonstrate the need for larger long-term studies to address issues of exercise adherence and the psychologic and functional benefits of exercise.

Activities of Daily Living↗

PubMed2004

Predictors of physical function in patients with peripherial arterial disease and claudication.

Limitation of walking due to claudication is the hallmark of peripheral arterial disease. The purpose of this secondary analysis was to identify biobehavioral predictors of physical function in peripheral arterial disease patients that included walking ability, gender, age, disease severity, environmental factors (social support), and medical comorbidity (arthritis). All subjects performed an exercise treadmill test to determine initial and absolute claudication distance. The sample consisted of 97 peripheral arterial disease patients, 71 (73%) men and 26 (27%) women, with a mean age of 73+/-8 years (range 52-90 years). Initial claudication distance occurred at 171.88+/-136.35 m. Absolute claudication distance was 421.03+/-286.37 m. A simultaneous multiple regression analysis was performed to determine predictors of physical function. The model accounted for 35% of the variance (p<0.001) and included personal characteristics (age, gender, years of education), severity of disease by ankle-brachial index, environmental factors of social support (marital status), absolute claudication distance, and arthritis. Education (p=0.011), absolute claudication distance (p=0.014), social support (p=0.026), arthritis (p=0.028), and age (p=0.033) were the strongest predictors of physical function. This study identifies biobehavioral factors that place peripheral arterial disease patients at greater risk for reduced physical function and provides a rationale for interventions that improve walking ability.

Activities of Daily Living↗

PubMed2003

Gender differences in perception of PAD: a pilot study.

Patients with peripheral arterial disease (PAD) report profound limitations in all domains of quality of life that are worse than those for patients with chronic pulmonary disease and moderate to severe heart failure. While claudication has detrimental effects on quality of life, little is understood about the factors that influence quality of life and whether these determinants are similar for men and women with PAD and claudication. The purpose of the present investigation was to evaluate the effect of claudication on quality of life in 71 men and 26 women (mean age 72 and 73 years respectively) with PAD. Disease severity as assessed by ankle brachial index (ABI) and community-based walking was similar for men and women, although men reported greater comorbid conditions than women. Despite the similarity in disease severity, women reported decreased physical functioning (p = 0.01), more bodily pain (p = 0.04) and greater mood disturbance (p = 0.012) than men. Claudication and PAD had a greater impact on women than on men and may result from the higher prevalence of mood disturbance and bodily pain reported by women.

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