A panel study in congestive heart failure to estimate the short-term effects from personal factors and environmental conditions on oxygen saturation and pulse rate.

OBJECTIVES: Recent studies suggest that persons with congestive heart failure (CHF) may be at higher risk for short-term effects of air pollution. This daily diary panel study in Montreal, Quebec, was carried out to determine whether oxygen saturation and pulse rate were associated with selected personal factors, weather conditions and air pollution. METHODS: Thirty-one subjects with CHF participated in this study in 2002 and 2003. Over a 2-month period, the investigators measured their oxygen saturation, pulse rate, weight and temperature each morning and recorded these and other data in a daily diary. Air pollution and weather conditions were obtained from fixed-site monitoring stations. The study made use of mixed regression models, adjusting for within-subject serial correlation and temporal trends, to determine the association between oxygen saturation and pulse rate and personal and environmental variables. Depending on the model, we accounted for the effects of a variety of personal variables (eg, body temperature, salt consumption) as well as nitrogen dioxide (NO2), ozone, maximum temperature and change in barometric pressure at 8:00 from the previous day. RESULTS: In multivariable analyses, the study found that oxygen saturation was reduced when subjects reported that they were ill, consumed salt, or drank liquids on the previous day and had higher body temperatures on the concurrent day (only the latter was statistically significant). Relative humidity and decreased atmospheric pressure from the previous day were associated with oxygen saturation. In univariate analyses, there was negative associations with concentrations of fine particulates, ozone, and sulphur dioxide (SO2), but only SO2 was significant after adjustment for the effects of weather. For pulse rate, no associations were found for the personal variables and in univariate analyses the study found positive associations with NO(2), fine particulates (aerodynamic diameter of 2.5 microm or under, PM(2.5)), SO2, and maximum temperature, although only the latter two were significant after adjustment for environmental effects. CONCLUSIONS: The findings from the present investigation suggest that personal and environmental conditions affect intermediate physiological parameters that may affect the health of CHF patients.

Treating the right patient at the right time: access to heart failure care.

Heart failure affects over 500,000 Canadians, and 50,000 new patients are diagnosed each year. The mortality remains staggering, with a five-year age-adjusted rate of 45%. Disease management programs for heart failure patients have been associated with improved outcomes, the use of evidence-based therapies, improved quality of care, and reduced costs, mortality and hospitalizations. Currently, national benchmarks and targets for access to care for cardiovascular procedures or office consultations do not exist. The present paper summarizes the currently available data, particularly focusing on the risk of adverse events as a function of waiting time, as well as on the identification of gaps in existing data on heart failure. Using best evidence and expert consensus, the present article also focuses on timely access to care for acute and chronic heart failure, including timely access to heart failure disease management programs and physician care (heart failure specialists, cardiologists, internists and general practitioners).

Treating the right patient at the right time: access to care in non-ST segment elevation acute coronary syndromes.

In 2004, the Canadian Cardiovascular Society formed an Access to Care Working Group with a mandate to use the best science and information available to establish reasonable triage categories and safe wait times for common cardiovascular services and procedures through a series of commentaries. The present commentary discusses the rationale for access benchmarks for urgent cardiac catheterization and revascularization, including hospital transfer in the setting of non-ST elevation acute coronary syndromes. The literature on standards of care, wait times, wait list management and clinical trials was reviewed. A survey of all cardiac catheterization directors in Canada was performed to develop an inventory of current practices in identifying and triaging patients. The Working Group recommended the following medically acceptable wait times for access to diagnostic catheterization and revascularization in patients presenting with acute coronary syndromes: for diagnostic catheterization and percutaneous coronary intervention, the target should be 24 h to 48 h for high-risk, three to five days for intermediate-risk and five to seven days for low-risk patients; for coronary artery bypass graft surgery, the target should be three to five days for high-risk, two to three weeks for intermediate-risk and six weeks for low-risk patients. All stakeholders must affirm the appropriateness of these standards and work continuously to achieve them. However, some questions remain around what are the best clinical risk markers to delineate the triage categories and the utility of clinical risk scores to assist clinicians in triaging patients for invasive therapies.

General commentary on access to cardiovascular care in Canada: universal access, but when? Treating the right patient at the right time.

In 2004, the Canadian Cardiovascular Society formed an Access to Care Working Group with a mandate to use the best science and information available to establish reasonable triage categories and safe wait times for common cardiovascular services and procedures through a series of commentaries. The present commentary is the first in the series and lays out issues regarding timely access to care that are common to all cardiovascular services and procedures. The commentary briefly describes the 'right' to timely access, wait lists as a health care system management tool, and the role of the physician as patient advocate and gatekeeper. It also provides advice to funders, administrators and providers who must monitor and manage wait times to improve access to cardiovascular care in Canada and restore the confidence of Canadians in their publicly funded health care system.

The long term prognosis in patients following thrombolysis for acute myocardial infarction: a view from a community hospital.

Thrombolysis in patients with acute myocardial infarction has been established to improve hospital survival. Less information is available about the long term evolution of unselected patients seen in community hospitals. Consequently, consecutive patients treated with thrombolysis for acute myocardial infarction and surviving until hospital discharge (n = 129) were followed for an average of 22 months. Mortality, recurrent ischemic events, coronary angiography and re-vascularizations were recorded for all patients. Two-year total and cardiovascular survival rates of 95 and 98% respectively were obtained with a conservative approach to early re-vascularization (n = 17, 13%). A history of prior myocardial infarction and early recurrent myocardial ischemia were significant predictors of increased cardiac events, while thallium stress testing provided no incremental value. Angiography and re-vascularizations were more frequently performed in younger patients (under 65 years old), anterior vs. inferior infarction and those with early residual ischemia. Women received less aggressive investigation and therapy then men and this may represent a gender bias, unmeasured residual confounding or the play of chance in a small sample size. Further studies are needed to confirm or refute these findings.

Medical decision making in the choice of a thrombolytic agent for acute myocardial infarction. Quebec Acute Coronary Care Working Group.

Little is known about how physicians make decisions when the evidence is incomplete or controversial. While thrombolysis improves survival following acute myocardial infarction (AMI), conflicting evidence exists as to any specific agent's superiority, particularly if cost-effectiveness is considered. Using a Bayesian hierarchical model, the authors examined the patient, physician, and hospital characteristics that are related to the decision-making process concerning the choice of thrombolytic agent in a prospective registry of 1,165 AMI patients receiving thrombolysis. Tissue plasminogen activator (t-PA) was administered to 432 patients (31.8%) and streptokinase (SK) to the remainder. The presence of an anterior infarction, a previous myocardial infarction, low blood pressure, a cardiologist decision maker, younger age, and receiving treatment within six hours after the start of symptoms were independent predictors of receiving t-PA. The levels of importance that physicians accorded to these patient characteristics differed according to their practicing institutions. Generally, they followed evidence-based medicine and reasonably targeted high-risk patients to receive the more expensive t-PA. However, they also preferentially treated younger patients, where only a small absolute advantage appears to exist.

The epidemiology of acute myocardial infarction and ischemic heart disease in Canada: data from 1976 to 1991.

OBJECTIVE: To present national trends in mortality rates for myocardial infarction and cardiovascular disease. DESIGN: Observational study using mortality statistics and hospital separation data from Statistics Canada for the period 1976 to 1991. RESULTS: Despite ageing of the population, there has been a substantial decrease in the number of deaths attributed to ischemic heart disease, from 51,000 in 1976 to 44,000 in 1991, with most of the decrease due to fewer deaths from myocardial infarction. Although age-adjusted death rates remain higher for men, the observed mortality decline has been more pronounced in men than in women. Age-adjusted separation rates have also decreased, suggesting a decrease in the incidence of myocardial infarction, particularly in the 45 to 64 year age group. The duration of hospital stay has shortened dramatically. CONCLUSIONS: From 1976 to 1991, mortality rates for ischemic heart disease in Canada decreased sharply, suggesting that advancements observed in clinical trials are being translated to the population level. The decrease appears to be due to both preventive measures and improved hospital care, but further studies are necessary to define better the relative contribution of each factor. The extent of this progress over the past 15 years is similar to the American experience.

Epidemiology of congestive heart failure: Canadian data from 1970 to 1989.

OBJECTIVE: To assess mortality rates from congestive heart failure in Canada from 1970 to 1989. DESIGN: Observational, retrospective design using national population and mortality data. MAIN RESULTS: There is a definite age gradient for deaths from congestive heart failure which, combined with a general ageing of the Canadian population, has lead to an increase in the absolute number of deaths. However, Standardized Mortality Ratios, which account for shifting population distributions, have shown steadily decreasing values for both men and women since 1980. CONCLUSIONS: Recent improvements in cardiology care demonstrated in controlled clinical trials appear also to be present in epidemiological studies.

Public policy and coronary stenting: a different perspective.

Coronary stenting is an innovative technology, which, in nonexperimental trials, has improved patient outcomes following threatened or abrupt closure. Randomized trials have shown a decrease in the restenosis rate and an accompanying decrease in repeat angioplasty in very specific patient groups. Stenting is becoming widespread in a variety of clinical situations where few controlled clinical trials have been performed. Further research is required to ascertain fully the safety, efficacy and cost effectiveness of coronary stenting in routine practice before public policy can be formulated sensibly.

Risk stratification in patients with non Q wave myocardial infarction: a role for thallium exercise testing.

The ability of maximal exercise thallium testing to stratify patients after non Q wave myocardial infarction was prospectively examined in 20 patients. Patients were enrolled in the study if there was no evidence of residual ischemia nor congestive heart failure during initial hospitalization. The thallium exercise test showed four patients to be at high risk, three of whom had successful revascularization. The remaining 16 patients were considered to be at low risk. There were no re-admissions for unstable angina, no myocardial infarctions and no deaths in the follow-up period (average 15 months). Thus patients with no evidence of early ischemia, no signs of left ventricular failure and a negative maximum thallium exercise test are at low risk following non Q wave myocardial infarction.

Use of abciximab (c7E3 Fab, ReoPro) as an adjunct to balloon angioplasty.

OBJECTIVE: To estimate the magnitude of the clinical benefits that may result from use of abciximab at the time of angioplasty and the cost of achieving them. DATA SOURCES: Four published randomized control trials. DATA SYNTHESIS: Meta-analysis of outcomes at six months. RESULTS: Use of abciximab in comparable high risk populations, in the manner described in these trials, is estimated to have the following effects: It does nto influence mortality within the first six months. It reduces the rate of myocardial infarction (MI) by 3.3/100 treatments with a 95% CI of 1.6 to 5.2. It may reduce the need for revascularization (angioplasty or coronary artery bypass graft) by 2.1/100 treatments (95% CI -1.0 to 5.0). It does not cause any significant increase in major hemorrhagic events. There is no evidence that it influences restenosis rates. The net cost per MI prevented would be approximately $44,000, ranging from approximately $29,000 to $71,000 on sensitivity analysis. The net cost per adverse event prevented (MI plus revascularization procedure) would be approximately $27,000 (sensitivity analysis $16,000 to $57,000). Use of abciximab for all of the approximately 17,487 angioplasties carried out in Canada each year may prevent 395 myocardial infarcts and 186 revascularization procedures, at an overall cost of approximately $29 million and a cost effectiveness of approximately $50,000 per adverse event prevented. (This assumes the same proportional reduction in events as in these four studies, and that 35% of procedures are high risk). SIGNIFICANCE: Possible eventual prolongation of life due to fewer periprocedural MIs with abciximab use cannot be quantified. Thus, these estimates of cost effectiveness cannot be used to compare this intervention directly with others in terms of dollars per life year saved. The field is evolving rapidly and these conclusions may soon have to be modified. Increasing use of stents will probably slightly reduce, but not abolish, the health benefits of abciximab use. These estimates are based on only four trials. However, until more trials are completed they provide the best available evidence on which to base policy decisions.

Long-term prognosis of patients presenting to the emergency room with decompensated congestive heart failure.

OBJECTIVES: This observational study was done to describe the long term prognosis of patients presenting to an emergency room with decompensated heart failure and to determine the factors that influence their survival. DESIGN: The routine clinical and laboratory characteristics of consecutive patients presenting to an emergency room with decompensated heart failure were documented and the patients followed for an average of 44 months (range 41 to 47). SETTING: One teaching hospital and one community-based hospital in Montreal, Quebec. PATIENTS: A prospective cohort of 153 consecutive patients presenting to the emergency room with decompensated heart failure. OUTCOME MEASURES: Total mortality was the main outcome. Survival status was validated by the government health insurance board. RESULTS: Survival was poor, with 61% dying within the 47-month follow-up. Univariate analysis revealed the following variables to be associated with decreased survival; low sodium (P < 0.001), decreased renal function (P < 0.001), prior hospitalization for decompensated heart failure (P < 0.001), intraventricular conduction defect (P < 0.002), failure despite prior use of angiotensin-converting enzyme (ACE) inhibitors (P < 0.005) and increased cardiac dimensions as determined by increased left ventricular end systolic diameter (P < 0.04). The multivariate analysis using the Cox proportional hazards model showed a prior admission for heart failure (relative risk [RR] 1.9 [P = 0.005], 95% confidence interval [CI] 1.2 to 2.9), hyponatremia (RR 2.1 [P = 0.005], 95% CI 1.2 to 3.5), presence of an intraventricular conduction delay (RR 1.9 [P = 0.003], 95% CI 1.2 to 2.9), and the cumulative required dose of intravenous furosemide (RR 1.7 [P = 0.03], 95% CI 1.1 to 2.8) to be associated with increased mortality. Patients with hyponatremia despite the use of ACE inhibitors were at greatest risk (RR 11.5 [P < 0.001], 95% CI 5.3 to 24.9). CONCLUSIONS: This prospective observational study confirms that the long term prognosis of patients needing hospitalization for congestive heart failure remains poor. Readily available acute-phase clinical variables may assist in predicting prognosis.

The hospital course and short term prognosis of patients presenting to the emergency room with decompensated congestive heart failure.

OBJECTIVES: This observational study was done to describe the characteristics, hospital course and short term prognosis of patients presenting to an emergency room with decompensated heart failure and to determine the parameters influencing the length of their hospital stay. DESIGN: The routine clinical and laboratory characteristics of consecutive patients presenting to an emergency room with decompensated heart failure were documented and the patients followed for six months. SETTING: One teaching hospital and one community-based hospital in Montreal, Quebec. PATIENTS: A prospective cohort of 153 consecutive patients presenting to the emergency room with decompensated heart failure. Follow-up was by clinic visit and telephone survey at one, three and six months. Follow-up was 100%. MEASURES OF OUTCOME: Length of hospital stay, in-hospital mortality, readmissions and after hospital discharge deaths were measured. RESULTS: The average length of hospital stay was 6.2 days with a skewed distribution ranging from one to 56 days. A multivariate analysis showed that the length of hospital stay was associated with increasing left atrial size (P < 0.05), an ischemic etiology of the heart failure (P < 0.03) and a slow response to diuretic therapy (P < 0.001). This mathematical model accounted for only a small amount of hospital stay variability (R2 = 0.22). Six month mortality and morbidity of these patients was high, with 23% dying and 30% readmitted for heart failure, but was independent of the duration of the initial hospitalization. CONCLUSIONS: This prospective study confirms that the hospital course for congestive heart failure is shortening. The six month prognosis of patients presenting to an emergency room for decompensated heart failure is poor and appears independent of the length of hospital stay.

Drospirenone and non-fatal venous thromboembolism: is there a risk difference by dosage of ethinyl-estradiol?

BACKGROUND: Previous studies concluded that there was an increased risk of non-fatal venous thromboembolism (VTE) with drospirenone. It is unknown whether the risk is differential by ethinyl-estradiol dosage. OBJECTIVES: To assess the risk of VTE with drospirenone and to determine whether drospirenone and ethinyl-estradiol 20 µg (DRSP/EE20) has a lower VTE risk than drospirenone and ethinyl-estradiol 30 µg (DRSP/EE30). METHODS: Our cohort included women aged 18-46 years taking drospirenone or levonorgestrel (LNG)-containing combined oral contraceptives (COCs) in the IMS claims database between 2001 and 2009. VTE was defined using ICD-9-CM coding and anticoagulation. The hazard ratio (HR) from Cox proportional hazards models was used to assess the VTE relative risk (RR) with drospirenone compared with levonorgestrel, adjusted by a propensity score used to control for baseline co-morbidity and stratified by EE dosage and user-type (new/current). RESULTS: The study included 238 683 drospirenone and 193,495 levonorgestrel users. Among new and current users, a 1.90-fold (95% CI, 1.51-2.39) increased VTE relative risk was observed for drospirenone (18.0 VTE/10,000 women-years) vs. levonorgestrel (8.9 VTE/10,000 women-years). In analysis of new users, DRSP/EE20 had a 2.35-fold (95% CI, 1.44-3.82) VTE RR versus LNG/EE20. New users of DRSP/EE30 observed an increased RR versus LNG/EE30 among women starting to use COCs between 2001 and 2006 (2.51, 95% CI, 1.12-5.64) but not between 2007 and 2009 (0.76, 95% CI, 0.42-1.39), attributable to an increased incidence rate with LNG/EE30 from 2007 to 2009. In direct comparison, DRSP/EE20 had an elevated risk of VTE compared with DRSP/EE30 (RR, 1.55; 95% CI, 0.99-2.41). CONCLUSIONS: We observed a modestly elevated risk of VTE with drospirenone, compared with levonorgestrel. The larger VTE incidence rate observed in DRSP/EE20 than in DRSP/EE30 and the increasing VTE incidence rate with levonorgestrel between 2007 and 2009 were unexpected.