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Biomedical subjects

Joaquin Barnoya

Publications and source records attributed to Joaquin Barnoya.

16 recordsLinked to original sources

Low-dose oral sildenafil for patients with pulmonary hypertension: a cost-effective solution in countries with limited resources.

INTRODUCTION: Pulmonary arterial hypertension, both primary and secondary, continues to pose a therapeutic problem. In this study, we evaluate the efficacy and safety of a low-dose of oral sildenafil in 10 patients with pulmonary arterial hypertension. METHODS: We administered a single daily dose of 0.5 milligrams per kilogram of sildenafil for 3 months to 10 patients with pulmonary arterial hypertension. Their average age was 26.8 years. Diagnoses were primary pulmonary arterial hypertension in 3 patients, and secondary pulmonary arterial hypertension due to congenital cardiac disease in the remaining 7 patients. Outcome measures included the clinical state, the mean pulmonary arterial pressure, and the indexed pulmonary vascular resistance; the latter two assessed at the beginning and at the end of the treatment period by cardiac catheterization. We also analysed the cost of the treatment. RESULTS: Oral treatment was well tolerated, and resulted in an improvement of the functional capacity in 9 of the 10 patients. Pulmonary arterial pressure decreased from 70 to 60 millimetres of mercury (p equal to 0.05), and indexed pulmonary vascular resistance decreased from 21.8 to 15.8 Wood units per square metre (p equal to 0.006). The mean cost per patient for 3 months on oral treatment with sildenafil was 120.99 American dollars. CONCLUSIONS: A low dose of 0.5 milligrams per kilogram per day of oral sildenafil, instead of 1 to 4 milligrams per kilogram per day, provided early clinical and haemodynamic improvements, and proved less expensive. Additional experience is now required to define more reliably the true long-term benefits of this therapy.

Administration, Oral↗

Radiofrequency catheter ablation of supraventricular tachycardia in children and adolescents : feasibility and cost-effectiveness in a low-income country.

The objective of this study is to provide results and costs of catheter ablation in children and adolescents in a low-income country. Reports from first-world countries have demonstrated the cost-effectiveness of radiofrequency catheter ablation (RFCA) compared to medical treatment of supraventricular tachycardia (SVT). The study included 28 patients younger than 18 years of age with SVT in a pediatric cardiology unit in Guatemala. All patients underwent RFCA. Clinical outcome and cost-effectiveness of RFCA compared to continued medical treatment were the end points. Twenty-four patients had successful ablation (85.7%). Mean age at RFCA was 11.42 +/- 3.49 years. Three patients underwent a second ablation, increasing the success rate to 96.4%. One remaining patient is awaiting a second procedure. At a mean follow-up of 13.69 +/- 7.16 months, all 27 patients who had a successful ablation remained in sinus rhythm. Mean cost per procedure was 4.9 times higher than that of medical treatment. However, the estimated cost of catheter ablation equal that of medical therapy after 5.1 years and is 3.4 times less after 20 years. Radiofrequency catheter ablation of SVT in children and adolescents is safe and cost-effective compared to medical therapy. Resources must be judiciously allocated, especially in low-income countries, to treat the largest number of pediatric patients.

Adolescent↗

Surgical versus percutaneous occlusion of ostium secundum atrial septal defects: results and cost-effective considerations in a low-income country.

OBJECTIVES: We compared the effectiveness and cost of percutaneous occlusion using an Amplatzer septal occluder (ASO) (AGA Medical Corp., Golden Valley, Minnesota) device compared with surgical closure of an ostium secundum atrial septal defect (ASD II) in Guatemala. BACKGROUND: The percutaneous occlusion of ASD II in first-world nations seems to offer better clinical results and lower cost compared with surgical closure. METHODS: We reviewed the clinical course of 111 patients referred to our institution for closure of isolated ASD II. Successful closure was assessed immediately after the procedures and at 12 months. Actual hospital costs were calculated for every patient who underwent either of the two procedures. RESULTS: Eighty-three patients with ASD II (75%) were selected for percutaneous occlusion with the ASO device, and the remaining 28 patients (25%) underwent surgical closure. In the device group, in 72 patients (86.7%) devices were successfully deployed. At immediate and 12-month follow-up, the complete closure rate was 87.5% (63 of 72 patients) and 97.2% (70 of 71 patients), respectively. In the surgical group, all patients had successful closure immediately after the procedure and at 12 months. Surgical closure offered a 27% cost savings in comparison with percutaneous occlusion (U.S. 3,329.50 dollars +/- 411.30 dollars and U.S. 4,521.03 dollars +/- 429.71 dollars; p < 0.001, respectively). Cost of the device (U.S. 2,930.00 dollars) proved to be the main cause for this difference. CONCLUSIONS: We confirmed the clinical advantages of percutaneous occlusion over surgical closure of ASD II. However, percutaneous occlusion costs were higher compared with surgical closure. In Guatemala, where health care resources are limited, ASD II closure with the ASO device did not prove to be cost-effective.

Adolescent↗

Pulmonary artery hypertension: is it really a contraindicating factor for early extubation in children after cardiac surgery?

BACKGROUND: One of the perceived major contraindications to early extubation after pediatric cardiac surgery is preoperative pulmonary arterial hypertension (PAH). The objective of this study is to present the results of early extubation (within 6 hours after open heart surgery) in children who had varying degrees of preoperative pulmonary arterial hypertension. METHODS: We reviewed the charts of 100 consecutive children who underwent subaortic ventricular septal defect closure and also had preoperative PAH. Outcomes measured included early extubation rate, clinical status of patients, and hospital costs. RESULTS: The median age at surgery was 2.5 years (range, 0.4 to 30). Sixty-five patients were extubated successfully in the operating room; 25 additional patients were extubated in the intensive care unit within 6 hours from surgery, increasing the early extubation rate from 65% to 90%. Postoperative complications were present in 12 patients; 10 of these patients required mechanical ventilation for more than 6 hours, and 1 of them died postoperatively in septic shock. Two patients required reintubation 25 and 26 hours, respectively, after initial extubation in the operating room, for causes unrelated to pulmonary hypertensive crises or ventilatory failure. The mean cost of procedures in patients who had successful early extubation was USD 3,786.50 +/- 302.45. Every additional day in the intensive care unit, in case of delayed extubation, increased the overall cost of the procedure by 10%. CONCLUSIONS: Pulmonary artery hypertension does not seems to be a contraindicating factor to early extubation in patients who underwent ventricular septal defect closure, and may be considered a feasible way to decrease postoperative intensive care unit stay and hospital costs.

Adolescent↗

The tobacco industry's worldwide ETS consultants project: European and Asian components.

BACKGROUND: The tobacco industry has formed regional environmental tobacco smoke (ETS) consultants programs in order to generate controversy on the issue of secondhand smoke (SHS) in Europe, Asia and Latin America. Only those countries in which the industry foresaw SHS restrictions were included. This paper describes the European and Asian components of the tobacco industry's worldwide ETS consultants program. METHODS: A systematic search was carried out of tobacco industry documents available on the Internet between October 2002 and February 2004. RESULTS: Beginning in 1987, Philip Morris assembled an international ETS consultants program in collaboration with other tobacco companies based on their market shares in different regions of the world. The law firm Covington & Burling contacted and hired consultants with a wide range of expertise, usually affiliated with an academic institution, in order to avoid direct contact with the industry. The objective of the program was to influence policy makers, media and the public by providing, through their consultants, 'accurate' (pro-industry) information concerning smoking regulations in public places and workplaces, indoor air quality and ventilation standards, and scientific claims regarding SHS. Consultants also conducted research related to SHS and organized and attended regional and international symposiums related to SHS without acknowledging industry funding. CONCLUSIONS: Despite evidence that the issue of smoke-free environments was close to emerging within the general public throughout the world in the late 1980s, the tobacco industry used its well-organized network of consultants to avoid SHS regulations in most of the world.

Asia↗

Cardiovascular effects of secondhand smoke: nearly as large as smoking.

BACKGROUND: Secondhand smoke increases the risk of coronary heart disease by approximately 30%. This effect is larger than one would expect on the basis of the risks associated with active smoking and the relative doses of tobacco smoke delivered to smokers and nonsmokers. METHODS AND RESULTS: We conducted a literature review of the research describing the mechanistic effects of secondhand smoke on the cardiovascular system, emphasizing research published since 1995, and compared the effects of secondhand smoke with the effects of active smoking. Evidence is rapidly accumulating that the cardiovascular system--platelet and endothelial function, arterial stiffness, atherosclerosis, oxidative stress, inflammation, heart rate variability, energy metabolism, and increased infarct size--is exquisitely sensitive to the toxins in secondhand smoke. The effects of even brief (minutes to hours) passive smoking are often nearly as large (averaging 80% to 90%) as chronic active smoking. CONCLUSIONS: The effects of secondhand smoke are substantial and rapid, explaining the relatively large risks that have been reported in epidemiological studies.

Cardiovascular Diseases↗

Association of the California tobacco control program with declines in lung cancer incidence.

OBJECTIVE: The California tobacco control program enacted in 1988 has been associated with declines in smoking and heart disease mortality. Since smoking also causes lung cancer, we investigated whether the program was associated with a decline in lung and other cancer incidence. METHODS: Age-adjusted incidence rates of lung and bladder cancer (which are caused by smoking) and prostate and brain cancer (which are not) in the San Francisco-Oakland (SFO) Surveillance Epidemiology End Results (SEER) registry and other eight SEER registries from 1975 to 1999 were fitted in multiple regression analyses accounting for the time lag between program implementation and its effects on cancer incidence. Cigarette consumption over time was also analyzed and related to lung cancer incidence. RESULTS: With a one year lag, the incidence of lung cancer in SFO, relative to eight other SEER registries, fell significantly below that predicted from the pre-1990 rates, by -0.981 (cases/100,000/year)/year (p = 0.001). With a three year lag, the incidence of bladder cancer fell by -0.234 (cases/100,000/year)/year (p = 0.066). No association of the program was observed on prostate or brain cancers in SFO. During the first decade, the Program was associated with about a 6% reduction in lung cancer incidence; state-wide that corresponds to about 11,000 cases avoided. CONCLUSION: A comprehensive tobacco control program is associated with a lower incidence of lung cancer.

Aged↗

The tobacco industry and secondhand smoke: lessons from Central and South America.

For more than 20 years the tobacco industry has considered secondhand smoke to be a threat to its viability. In this article, we describe why secondhand smoke is important to tobacco control and how the tobacco industry's "Latin Project" sought to prevent the creation of smoke-free workplaces and public places in Central and South America. Eliminating secondhand smoke exposure not only reduces the risk of cardiovascular and other diseases, but also creates an environment that substantially reduces smoking and cigarette consumption among smokers. The "Latin Project" was initiated in 1991 by Philip Morris and British American Tobacco and managed by the law firm Covington & Burling. The project assembled a network of well-placed physicians and scientists to divert the attention away from secondhand smoke toward other indoor air pollutants. As proven in Central and South America, the tobacco industry has manipulated the secondhand smoke issue in order to avoid the development of smoke-free environments. Sub-Saharan Africa, facing an epidemiologic transition similar to the one experienced by Central and South America, should be aware of tobacco industry tactics. Further delay in implementing smoke-free environments will only increase the burden of cardiovascular disease in both areas of the world.

Africa South of the Sahara↗

The p53 tumour suppressor gene and the tobacco industry: research, debate, and conflict of interest.

Mutations in the p53 tumour suppressor gene lead to uncontrolled cell division and are found in over 50% of all human tumours, including 60% of lung cancers. Research published in 1996 by Denissenko and colleagues demonstrated patterned in-vitro mutagenic effects on p53 of benzo[a]pyrene, a carcinogen present in tobacco smoke. We investigated the tobacco industry's response to p53 research linking smoking to cancer. We searched online tobacco document archives, including the Legacy Tobacco Documents Library and Tobacco Documents Online, and archives maintained by tobacco companies such as Philip Morris and R J Reynolds. Documents were also obtained from the British American Tobacco Company depository in Guildford, UK. Informal correspondence was carried out with scientists, lawyers, and tobacco control experts in the USA and Europe. We found that executives and scientists at the highest levels of the tobacco industry anticipated and carefully monitored p53 research. The tobacco industry's own scientists conducted research which appeared to cast doubt on the link between smoking and p53 mutations. Researchers and a journal editor with tobacco industry ties participated in the publication of this research in a peer-reviewed journal without clear disclosure of their tobacco industry links. Tobacco industry responses to research linking smoking to carcinogenic p53 mutations mirror prior industry efforts to challenge the science linking smoking and lung cancer. The extent of tobacco industry involvement in p53 research and the potential conflict of interest discussed here demonstrate the need for consistent standards for the disclosure and evaluation of such potential conflicts in biomedical research.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗