Gender differences in clinical outcome after coronary stenting

OBJECTIVE: The purpose of this study was to determine the effect of gender differences in the clinical outcome of women and men submitted to coronary stenting at our institution. BACKGROUND: Studies regarding gender differences in outcome after invasive coronary interventions have revealed conflicting data regarding risk for complications. Some studies have pointed to female gender as a predictor of mortality and complications after those procedures. To our knowledge no such evaluation has been performed in our country. METHODS: We reviewed the medical records, cardiac catheterization and procedural data of 205 men and 122 women referred to our section that underwent coronary stenting at the Cardiovascular Center of Puerto Rico and the Caribbean from July 1, 1998 to March 30, 1999. The clinical and procedural characteristics and the immediate procedure-related complications were analyzed. Clinical events during the six-month period after the procedure were evaluated in patients that returned for follow-up to the section. Student's t-test or Mann-Whitney-Wilcoxon, when appropriate, was used to compare continuous data. The chi-square test or Fisher's exact test, was employed to compare categorical data. RESULTS: The initial procedural success and the frequency of early complications were comparable to those informed in the medical literature and not statistically significant between genders. The only statistically significant gender differences in outcome occurred in men who had higher re-hospitalization and re-intervention rates in the six-month period after the procedure. A lower mean ejection fraction and higher previous history of myocardial infarction and cigarette smoking in this group could have been related to the higher complication rate. CONCLUSION: Although the sample examined is small, its findings point to the need of a larger prospective study to further explore the possibility that the previously reported differences in outcome in men and women submitted to interventional procedures would have a stronger relation to clinical factors than to the direct effect of gender.

Surgical versus interventional procedures in patients with multivessel coronary artery disease

OBJECTIVE: This study examined the clinical characteristics, risk factors, indications and post-intervention complications of patients with multivessel coronary artery disease (CAD) submitted to either percutaneous transluminal coronary angioplasty (PTCA) and/or stent placement versus isolated coronary artery bypass grafting (CABG). BACKGROUND: Several studies have examined the relative safety and outcome of patients submitted to those interventional procedures compared to CABG. Limited information is available regarding that subject in Puerto Rico. METHODS: We performed a retrospective analysis of the clinical, angiographic, operative, interventional, post-operative and post-interventional data of patients submitted to those procedures in our institution from January 1998 to August 1998. There were 53 patients in the interventional group and 206 patients in the CAGB group. Comparison of quantitative variables by procedure was based on Student t test or Mann-Whitney-Wilcoxon test; categorical variables were compared using Pearson's chi-square or Fisher's exact test. RESULTS: There were no significant differences in age, body surface area, or cardiac risk factors. The most common pre-existing cardiovascular diagnosis was unstable angina. Three-vessel disease was the most common angiographic finding among CABG patients (61.7 percent). Two-vessel disease without left anterior descending coronary artery obstruction was significantly more common in the PTCA/Stent patients (58.5 percent). The vast majority (97.6 percent) of patients in the PTCA/Stent group and 52.4 percent of the CABG group had two-vessel intervention. A significantly higher frequency of complications occurred in the CABG group. However, the incidence of major complications, in both groups was not statistically different. Atrial arrhythmias were significantly more frequent in the CABG group. CONCLUSION: A larger prospective study should be conducted in order to corroborate these preliminary findings and seek effective solution to any identifiable problem.

Perioperative outcomes in octogenarians undergoing cardiac surgery in Puerto Rico

With the advances in surgical techniques and the advent of an aging population, the application of cardiac surgeries has broadened to include those patients over the age of 80. In order to characterize the in-hospital morbidity and mortality of elderly patients undergoing cardiac surgery at our cardiovascular center, a retrospective review of all medical records of consecutive octogenarian patients was made. Between January 1998 and April 1999, 76 patients (mean age (SD), 82.5 (2.6)) underwent cardiac surgery, of which, 61.8 percent were males. Surgical procedures consisted of isolated coronary artery bypass grafting (CABG)in 64 patients, isolated aortic valve replacement (AVR) in 4 patients, combined CABG and left carotid endarterectomy in 4 patients, combined CABG and AVR in 2 patients, combined CABG and aortic aneurysm repair in 1 patient and combined AVR and aortic dissection repair in 1 patient. Surgery was elective in 51.3 percent of patients and seventy-one percent (54) experienced at least one postoperative complication. The most common complication was atrial arrhythmia (28) followed by low cardiac output (23) and pneumonia (16). Hospital mortality occurred in 11 (14.7 percent) patients, an estimate in agreement with previous published studies on octogenarians. Since the number of patients studied was small, these results require confirmation by other cardiovascular centers in the island. Further research to determine independent predictors of postoperative morbidity and mortality, to assess survival and quality of life after cardiac surgery and to evaluate cost-effectiveness considering new trends in managed health care is warranted.

Métodos alternos de anális estadístico en epidemiología: frequentista, verosimilitud y bayesiano / Alternative methods of statistical analysis in epidemiology: frequency, likelihood, and Bayesian

Una de las críticas a la pruebas de significancia, basadas en los intervalos de confianza y en el valor de p (p-value), es su interpretación utilizando el concepto de repeticiones. Este tipo de interpretación se conoce como la interpretación frecuentista (frequentist interpretation), la cual indica una repetición de las muestras de estudio bajo condiciones similares, condición difícil de aplicar en estudios epidemiológicos observacionales. Por lo tanto, se han desarrollado otras alternativas que puedan contestar esta interrogante. Una de estas alternativas es el cálculo de los intervalos de verosimilitud (likelihood intervals); otra se obtiene mediante el cálculo de intervalos bayesianos (Bayesian intervals). En este documento presentamos una breve descripción de estos métodos y su aplicaciones en estudios epidemiológicos. Se espera que con el desarrollo de nuevos programas de computación, las aplicaciones de estos métodos irán en aumento, por lo que los investigadores de la salud tendrán otras alternativas de análisis y evaluación de datos estadísticos.

Variations in the survival probabilities of the PVC-protected red mangrove propagules: testing the encased replanting technique

The EcoEléctrica Mangrove Planting Project, a five-year voluntary effort, has the purpose of testing a recently developed mangrove planting technique at the EcoEléctrica site in Peñuelas, Puerto Rico. The goal of the project is to provide empirical validation to promote or improve the technique to be used in recovering mangrove ecosystems in Puerto Rico and United States. The research presented herein analyzed the information collected on the first two years of the project. The proportions of remaining casings and seeds per study zone were compared using the chi-square distribution. Zone 1 had the least pipes lost while Zone 4 had the most (p < 0.05). Forty-three percent of the seeds in Zone 1 remained in the casing, while 26 percent remained in Zone 2 (p = 0.03). Median growth rates of seeds per study zone showed that Zone 1 had the highest median growth rates. Survival analysis described the survival experience of the seeds, and differences in survival probabilities were compared with the log-rank test. Zone 1 seeds had a better survival experience compared to Zones 2, 3 and 4 (p < 0.0001). Survival probabilities for being free of spots were over 60 percent during the whole study period. No significant differences were observed in the survival experience with the use-or-no use of casing extensions (p = 0.40), and the use-or-no use of nursed seeds (p = 0.26). Differences in survival probabilities might be attributed to variations in wave energy, depth or substrate conditions. This hypothesis will be evaluated in the second phase of the study.

Aspectos metodológicos de bioestadística y epidemiología en un ensayo clínico / Methodological aspects of biostatistics and epidemiology in a clinical trial

Various methodological issues in biostatistics and epidemiology which are relevant for the development of a clinical trial are discussed. A brief set of definitions regarding clinical trials and methods for the assignment of treatments is presented. In addition, methods to reduce the possibility of bias that may be introduced into a clinical trial are summarized. The different elements that must be included in the informed consent form are defined. General considerations for data analysis and for sample size required to obtain an adequate statistical power are illustrated. Finally, critical questions that can be used for the review of the literature on clinical trials are suggested

Early postoperative complications after coronary artery bypass grafting at the Cardiovascular Center of Puerto Rico and the Caribbean

OBJECTIVES: This study describes the preoperative cardiovascular characteristics, intraoperative data, in-hospital complications and factors associated to procedural-related complications in patients undergoing coronary artery bypass grafting (CABG). BACKGROUND: There is a growing body of evidence of CABG safety and efficacy; however, limited data is available regarding the value of this surgical procedure in the Puerto Rican population. METHODS: We retrospectively reviewed the medical records of 200 consecutive patients submitted to CABG at the Cardiovascular Center of Puerto Rico and the Caribbean over a three-month period in 1997. Bivariate and multivariate analyses were performed to determine factors associated with the occurrence of complications. RESULTS: The most frequent cardiac risk factor was hypertension (77 per cent); stable angina (60.5 per cent) was the predominant cardiac clinical diagnosis. Three vessel disease with proximal left anterior descending coronary artery stenosis (42.1 per cent) was the most common anatomical lesion. The rate of major complications such as death (3 per cent), perioperative myocardial infarction (2 per cent), reoperation to control bleeding (1.5 per cent), pulmonary embolism (1 per cent), and stroke (1 per cent) was low and similar to the rate reported elsewhere. Multivariate analysis showed that non-use of LIMA graft, extended hospital stay, prolonged cardiopulmonary bypass time, and left ventricular dysfunction were significantly associated with the occurrence of complications (p < 0.05); on the other hand, there was a trend for older age to be associated with the occurrence of complications (p = 0.057). CONCLUSIONS: CABG is being performed with an acceptably low complication rate in this institution.

Association between dietary fat and breast cancer in Puerto Rican postmenopausal women attending a breast cancer clinic

OBJECTIVE: A pilot case-control study was conducted to examine the possible association between dietary fat intake and the development of postmenopausal breast cancer. BACKGROUND: Studies regarding the association between dietary fat intake and the development of breast cancer among postmenopausal women are lacking in Puerto Rico. METHODS: Eighteen cases and eighteen controls were interviewed to obtain sociodemographic information, medical history and dietary fat intake. A semiquantitative food frequency questionnaire containing 67 food items was used to collect the dietary information. RESULTS: Unadjusted odds ratios (OR) and their 95 per cent confidence intervals (CI) showed a non-significant positive association for total fat intake and the development of postmenopausal breast cancer (OR = 1.57; 95 per cent CI: 0.42-5.90, p = 0.25). The same non significant positive association was found for saturated fat intake (OR = 1.57; 95 per cent CI: 0.42-5.90, p = 0.25). Polyunsaturated fat (OR = 1.25; 95 per cent CI: 0.34-4.64, p = 0.37) and monounsaturated fat (OR = 1.25; 95 per cent CI: 0.34-4.64, p = 0.37) were also positively associated with postmenopausal breast cancer, although the associations were not statistically significant. CONCLUSIONS: These results are consistent with other case-control studies that have shown non-significant positive associations between total fat and the different components of dietary fat and postmenopausal breast cancer.

Dietary fat and breast cancer: a brief update on current knowledge

Descriptive epidemiologic data suggest a relationship between consumption of high fat diets and breast cancer; although these data can be potentially confounded by other causative exposures. Results of published case-control and cohort studies are inconclusive. Nevertheless, dietary fat significantly affects mammary tumorigenesis in mice and rats in laboratory experiments. We will review current epidemiologic and animal studies, explain the possible mechanisms of how dietary fat may affect breast cancer, and provide preliminary dietary recommendations.