In the News

New definition of MI, average lifespan of heart failure patients, and more.

New definition of MI released

A consensus document from several cardiology organizations recently provided new official definitions of myocardial infarction (MI).

The definition, which was the third one released since 2000, was developed by an expert task force from the European Society of Cardiology, American College of Cardiology Foundation, American Heart Association, Inc., and the World Heart Federation. It defined acute MI by the following criteria:

  • A change in cardiac biomarkers (preferably cardiac troponin) with at least one value above the 99th percentile upper reference limit, and one of the following: symptoms of ischemia; new significant ST-segment-T wave changes or left bundle-branch block (LBBB); pathological Q waves on an electrocardiogram (ECG); imaging evidence of new loss of viable myocardium or regional wall motion abnormality; and/or intracoronary thrombus identified by angiography or autopsy.
  • In cases where cardiac death occurs before biomarkers can be obtained or would have increased, MI is defined by ischemia symptoms and new ECG changes or new LBBB.

The new definition was developed to account for increasingly more sensitive biomarkers and imaging techniques, as well as new management techniques that result in less cardiac damage, the task force said. They noted that it's also important to characterize the type of MI.

Percutaneous coronary intervention-related MI is defined, in patients with normal baseline troponin, as elevation >5 × 99th percentile. If the baseline troponin value was elevated, it is defined as a rise of more than 20%. In addition, in all patients, one of the following should be present: ischemic symptoms, ischemic ECG changes, angiographic findings consistent with a procedural complication, or imaging evidence of new loss of viable myocardium or regional wall motion abnormality.

Coronary artery bypass grafting-related MI is defined, in patients with normal baseline troponin, as elevation >10 × 99th percentile. In addition, one of the following should be present: new pathological Q waves or new LBBB, angiographic evidence of new graft or new native coronary artery occlusion, or imaging evidence of new loss of viable myocardium or regional wall motion abnormality.

Prior myocardial infarction is defined by any one of the following:

  • pathological Q waves with or without symptoms, in the absence of non-ischemic causes,
  • imaging evidence of a region of lost viable myocardium that is thinned and fails to contract, in the absence of a non-ischemic cause, or
  • pathological findings of a prior MI.

The consensus document was published in the Oct. 20 European Heart Journal.

Average lifespan of heart failure patients at discharge is 5.5 years

The average lifespan of heart failure patients at hospital discharge is 5.5 years, but individual life expectancy greatly varies by age, gender and comorbidities, a study found.

Researchers examined data on 7,865 heart failure patients discharged from Ontario hospitals between 1999 and 2000 whose information had been collected as part of a provincial quality improvement initiative. They linked patients to administrative data and tracked them longitudinally until March 31, 2010. Researchers obtained detailed clinical information via medical charts; they used vital statistics to obtain death data. The mean age of the patients was 75.4 years and 50.2% were female. Results were published in the September Journal of General Internal Medicine.

The average lifespan, using the Kaplan-D.E.A.L.E. (Declining Exponential Approximation of Life Expectancy) method, was 5.5 years. There was a difference of 4.5 years between those with low and high 30-day mortality risk index scores. Gender and age also were big factors, with low-risk women younger than 50 living an average of 19.5 years after discharge, and high-risk octogenarian males living 2.9 years after discharge, on average. Patients with impaired left ventricular function had lifespans that were lower by 0.13 years versus those with preserved left ventricular function. Having three or more comorbidities reduced one's lifespan by a year compared to those with no comorbidities. Seventeen percent of patients died within six months, and 27% within one year, despite having predicted lifespans of more than one year.

The life expectancies of patients discharged from the hospital with heart failure vary widely across clinical risk data strata and comorbidity burden, and are comparable to many advanced stages of cancer, the authors wrote. As in previous studies, the predictions lacked precision for patients at or near the end of life, thus risk-assessment methods and/or criteria still need improvement, they said. “While the clinical applicability of such data necessitates further research, such data could have utility for clinical decision-making, system-planning and prioritization, particularly among those with limited life-expectancies,” they concluded.

Start ART in all HIV-infected adults, expert panel says

All adults with HIV should be offered antiretroviral therapy (ART) regardless of CD4 cell count, according to the 2012 International Antiviral Society-USA panel recommendations.

Experts updated the previous 2010 guidelines based on observational cohort data finding all HIV-positive patients may benefit from ART and data from a randomized controlled trial showing that ART reduces the likelihood of spreading HIV. The findings appeared in the July 25 Journal of the American Medical Association.

There is no CD4 cell count threshold at which starting therapy is contraindicated, but the strength of the recommendation and the quality of the evidence supporting therapy increase as the CD4 cell count decreases and in patients who are pregnant, have hepatitis B or C, are older than 60 years, or have HIV-associated nephropathy. Ongoing monitoring of patients' CD4 cell count, HIV-1 RNA levels, ART adherence, HIV-drug resistance, and quality-of-care indicators is recommended.

Because any drug regimen is lifelong, therapy choices should account for patient convenience and tolerability. Recommended initial therapy is still a combination of two nucleoside/nucleotide reverse transcriptase inhibitors and a potent third agent (generally a nonnucleoside reverse transcriptase inhibitor, a ritonavir-boosted protease inhibitor, an integrase strand transfer inhibitor, or, rarely, an agent that blocks the CC chemokine receptor 5).

In the same issue of JAMA, researchers reported that HIV-infected and uninfected women with a normal Pap test and a negative test result for oncogenic human papillomavirus (HPV) DNA at study enrollment had a similar risk of cervical precancer and cancer after five years of follow-up. Additional observational studies or a randomized clinical trial may be necessary before clinical guideline committees consider whether to expand current recommendations regarding HPV co-testing to HIV-infected women, according to the study authors.

“More broadly, the current investigation highlights the potential for a new era of molecular testing, including HPV as well as other biomarkers, to improve cervical cancer screening in HIV-infected women,” the authors wrote.

Interaction between clopidogrel, PPIs clinically unimportant

The interaction between proton-pump inhibitors (PPIs) and clopidogrel is clinically unimportant, researchers found.

Researchers conducted an observational cohort study and self-controlled case series among 24,471 patients receiving clopidogrel and aspirin, using the United Kingdom General Practice Research Database with linked data from the Myocardial Ischaemia National Audit Project (MINAP) and the Office for National Statistics. Results were published online by BMJ on July 10.

Of the 24,471 patients prescribed clopidogrel and aspirin, 12,439 (50%) were also prescribed a proton-pump inhibitor at some time during the study. Death or myocardial infarction occurred in 1,419 patients (11%) receiving a proton-pump inhibitor compared with 1,341 patients (8%) who were not. Multivariate analysis showed the hazard ratio for the association between proton-pump inhibitor use and death or incident myocardial infarction was 1.37 (95% CI, 1.27 to 1.48). Comparable results were seen for secondary outcomes and with other 2C19 inhibitors and with non-2C19 inhibitors.

A self-controlled case series design to remove the effect of differences between patients showed no association between proton-pump inhibitor use and myocardial infarction, with a rate ratio of 0.75 (95% CI, 0.55 to 1.01). There was no association with myocardial infarction for other 2C19 inhibitors/non-inhibitors.

The association found in the cohort analysis is unlikely to be causal for several reasons, the authors wrote:

  • The effect is not specific to vascular events, as shown by the hazard ratio for non-vascular mortality of 1.61 (95% CI, 1.42 to 1.82).
  • People who are prescribed long-term drug treatment in addition to clopidogrel are inherently at higher risk of harmful outcomes, but not through a causal association with the treatments they receive.
  • Cohort results could be explained by confounding. Results from the self-controlled case series, which removed all fixed confounding, provided no evidence of an increased risk of incident myocardial infarction during periods when patients were exposed to any proton-pump inhibitors (incident rate ratio [IRR], 0.75; 95% CI, 0.55 to 1.01), ranitidine (IRR, 0.57; 95% CI, 0.31 to 1.06) or citalopram (IRR, 0.84; 95% CI, 0.49 to 1.45).

“Taken together, a plausible explanation for our results is that the increased risk of both vascular and non-vascular harmful outcomes seen in patients receiving proton pump inhibitors and other long term drugs could be caused by confounding between people,” the authors wrote. “Although accounting for such confounding can be difficult, the use of approaches such as the self-controlled case series, which is less prone to differences between people, can solve this problem. The lack of association seen between proton pump inhibitor use and myocardial infarction with this approach argues against a clinically relevant interaction between clopidogrel and proton pump inhibitors.”

An editorial expanded on the use of a self-controlled study to resolve residual confounding and offered clinical advice. “Because patients with cardiovascular disease are at an especially high risk for morbidity and mortality after an acute gastrointestinal haemorrhage, clinicians should strongly consider prescribing a PPI to all patients who use dual antiplatelet drugs, especially in the presence of additional risk factors for gastrointestinal complications, such as age over 60; concomitant use of non-steroidal anti-inflammatory drugs, other anticoagulants, or corticosteroids; and important medical comorbidities,” the editorial stated.

U.S. in-hospital death rates after cardiac arrest declined from 2001 to 2009

In-hospital mortality from cardiac arrest declined in the U.S. from 2001 to 2009, according to a recent study.

Researchers used data from the U.S. National Inpatient Sample to determine whether in-hospital mortality rates after cardiac arrest have improved in the past decade, which was marked by noteworthy advances in post-resuscitation care, including therapeutic hypothermia. The ICD-9 code 427.5 was used to determine which patients were hospitalized with cardiac arrest in the U.S. from 2001 to 2009. Patients were stratified by age, sex and race, and comorbid conditions were also assessed. In-hospital mortality was the study's main outcome measure. The results were published in the July 31 Circulation.

Overall, 1,190,860 patients had a hospitalization for cardiac arrest over the study period. The in-hospital mortality rate decreased each year, from 69.6% in 2001 to 57.8% in 2009. The researchers performed a multivariable analysis controlling for age, sex, race and comorbid conditions and found a strong independent correlation between hospitalization in an earlier year and in-hospital death. In addition, all subgroups of age, sex, race and comorbidity saw a decrease in the in-hospital mortality rate over time.

The authors noted that their study was limited by lack of data on the location of the cardiac arrests, the initial cardiac rhythm, and cardiopulmonary resuscitation, among other factors. They also stressed that their findings apply only to patients who survived cardiac arrest long enough to be hospitalized. However, they concluded that the data indicate a substantial, consistent decline in mortality among patients hospitalized for cardiac arrest over the study period. “Although we cannot definitively conclude which specific factor is responsible for the decline in mortality, our results suggest that advances in post-resuscitation care have positively impacted survival rates of patients hospitalized with cardiac arrest in the United States from 2001 to 2009,” the authors wrote.

Hospital-initiated transition interventions can improve stroke, MI outcomes

Transition-of-care interventions initiated in the hospital can help improve outcomes in adult patients with stroke and myocardial infarction (MI), according to a study.

Researchers performed a systematic review of studies published from January 2000 to March 2012 to examine whether transitional care interventions led to benefit or harms in patients who were hospitalized for acute stroke or MI. Observational studies or trials were included if they were in English, compared transitional and usual care in adults with the conditions of interest, and reported patient, caregiver, process or systems outcomes within one year of discharge from the hospital. Data were extracted on study design, population, quality, intervention, and patient- and system-level outcomes. The results were published in the Sept. 18 Annals of Internal Medicine.

The review included 62 articles involving 44 studies, 27 of acute stroke and 17 of MI. A total of four intervention categories were studied: hospital-initiated support (14 trials), patient and family education (7 trials), community-based support (20 trials) and chronic disease management (3 trials). Sixty-eight percent of the studies were judged to be of fair quality.

All of the transitions were from a hospital or from inpatient rehab to patients' homes. Moderate-strength evidence indicated that hospital-initiated support reduced length of stay for acute stroke, and low-strength evidence indicated that it reduced mortality for MI. Evidence was insufficient to determine the benefits and harms of the other types of transitional care interventions.

The authors acknowledged that few of the included studies were of high quality, that the usual care group was not often well defined, and that only six of the studies were done in the United States, among other limitations. They called for more studies in this area, especially in U.S. settings.

“As the U.S. population ages and the number of patients who have MI or stroke increases, it is imperative to have transitional care interventions proven to be effective in improving functional outcomes, facilitating transfer of care from a hospital-based system to a community-based system, and preventing rehospitalization and adverse events,” the authors wrote.

Hospitalist preoperative clinic improved outcomes

A hospitalist-run preoperative clinic improved outcomes for the sickest patients and general perioperative processes, a study found.

Researchers at a Veterans Administration medical center conducted a pre/post retrospective review after the implementation of a new medical preoperative clinic staffed by hospitalists. Non-cardiac surgical patients had previously been evaluated only by anesthesia staff. Under the new system, patients were seen by a mid-level medical provider (overseen by a hospitalist) within 30 days before surgery and were evaluated by an anesthesiologist only on the day of surgery. Patients seen in the year before the hospitalist clinic was started were compared to those seen in the year after implementation, and those undergoing cardiothoracic surgery (who were never seen at the clinic) were used as internal controls. Results were published by the Journal of Hospital Medicine on Sept. 7.

The study found that patients who had an American Society of Anesthesiologists score of 3 or higher had a shorter length of stay under the new system (P<0.0001). The clinic was also associated with increases in use of beta-blockers (P<0.0001) and stress tests (P=0.012). There was also a trend toward fewer same-day, medically avoidable surgery cancellations (8.5% vs. 4.9%; P=0.065) and a small absolute reduction in mortality (1.27% vs. 0.36%; P=0.0158) after the hospitalists took over the clinic. The control group of cardiothoracic patients showed no change in length of stay and a smaller reduction in mortality during the same period.

Researchers concluded that a medical preoperative evaluation may benefit both complex patients and the hospital (through improvements in processes and outcomes), although they noted data were lacking for a complete cost-effectiveness analysis. The study couldn't identify what specific factors made the clinic effective, but possible contributors include perioperative medication adjustments and identification of high-risk patients for whom surgery should be deferred.

Other health care systems, particularly those with many complex patients who lack primary care access, could potentially benefit from this system or some other that adds medical expertise to preoperative evaluations, the authors said. Perhaps in some programs anesthesiologists could collaborate with hospitalists or general internists to evaluate patients, they suggested. In this case, the hospital hired a hospitalist to take over preoperative clinic supervision from an anesthesiologist, whose time was freed up for other clinical activity.

Hyponatremia linked to higher costs, longer stays, deaths

Hyponatremia predicts longer hospitalizations, higher costs and 30-day readmissions, and in the preoperative setting is linked to greater 30-day mortality, two studies have found.

In the first study, a retrospective analysis, researchers used the Premier Hospital Database to examine health care utilization and costs among hyponatremia patients. Eligible inpatients were discharged between Jan. 1, 2007 and March 31, 2010, were older than 18 years at admission, and had either a primary or secondary diagnosis of hyponatremia or hyposmolality. Researchers matched these patients to a non-hyponatremia cohort and used bivariate/multivariate statistics to evaluate the differences in costs, readmission and lengths of stay. Results were published online Sept. 7 by the Journal of Hospital Medicine.

Length of stay (LOS) was greater for the hyponatremia versus non-hyponatremia patients (8.8 ± 10.3 vs. 7.7 ± 8.5 days; P<0.001), as were hospitalization costs ($15,281 ± $24,054 vs. $13,439 ± $22,198; P<0.001), intensive care unit (ICU) admissions (23.1% vs. 22.1%; P<0.001), ICU length of stay (5.5 ± 7.9 vs. 4.9 ± 7.1 days; P<0.001), and ICU costs ($8,525 ± $13,342 vs. $7,597 ± $12,695; P<0.001). Patients in the hyponatremia cohort were also more likely to be readmitted to the hospital for any cause at 30 days (17.5% vs. 16.4%; P<0.001). Hyponatremia “represents a potential target for intervention to reduce healthcare expenditures for a large population of hospitalized hyponatremic patients,” the authors wrote.

In the second study, researchers assembled a cohort through the American College of Surgeons National Surgical Quality Improvement Program Participant Use Data Files to identify 964,263 adults undergoing major surgery between 2005 and 2010, then observed them for 30-day outcomes. They used multivariable logistic regression to estimate risks for death, wound infections, pneumonia and major coronary events within 30 days of surgery, and quantile regression to estimate differences in average length of stay. Results were published online Sept. 10 by Archives of Internal Medicine.

The 75,423 patients with preoperative hyponatremia (sodium level <135 mEq/L) had a higher risk of 30-day mortality than the 888,840 patients with normal baseline sodium levels of 135-144 mEq/L (5.2% vs. 1.3%; adjusted odds ratio [OR], 1.44). The finding was consistent in all subgroups, and particularly strong in patients undergoing non-emergency surgery (OR, 1.59; P<0.001 for interaction) and American Society of Anesthesiologists class 1 and 2 patients (OR, 1.93; P<0.001 for interaction). Hyponatremia was also associated with a greater risk of perioperative major coronary events (1.8% vs. 0.7%; OR, 1.21), wound infections (7.4% vs. 4.6%; OR, 1.24) and pneumonia (3.7% vs. 1.5%; OR, 1.17), and longer median lengths of stay by about one day.

The preoperative hyponatremia cohort had a 44% higher risk of 30-day perioperative mortality after adjustment for all other risk factors, and excess risk existed even for patients with mild hyponatremia, the study authors noted. They cautioned that further research is needed to determine whether correcting preoperative hyponatremia will mitigate risks. Large or rapid changes to sodium levels could be harmful, they noted. Underlying causes of hyponatremia should be determined in these patients, and preoperative hyponatremia “should be considered a prognostic marker for perioperative complications” and should alert physicians to a situation “necessitating closer surveillance in the perioperative period,” they wrote.

Interventions at hospital discharge help transitions to primary care

Certain interventions at hospital discharge appear to help improve handoffs to primary care, but more research is needed to determine how and why, a study indicates.

Researchers performed a systematic review of randomized, controlled trials published from January 1990 to March 2011 to examine interventions meant to improve the transition between hospital discharge and primary care. All trials involved transitions from the hospital to primary care or to home and were restricted to adult patients (except pregnant women) without a psychiatric diagnosis. Data were extracted on study objectives, setting and design, intervention, and outcomes, and studies were categorized by quality, sample size, intervention characteristics, outcome, direction of effects and statistical significance. Results were published in the Sept. 18 Annals of Internal Medicine.

A total of 36 studies were included in the review. Of these, 25 (69.4%) showed a statistically significant effect favoring the intervention and 34 (94.4%) involved multicomponent interventions. Medication reconciliation, electronic generation of discharge summaries, discharge planning, shared follow-up between hospital- and community-based clinicians, electronic discharge notifications, and Web-accessible discharge summaries for primary care clinicians were found to be effective. Effective interventions had statistically significant effects on reducing hospital use (e.g., rehospitalizations), improving care continuity (e.g., medication reconciliation) and improving patient status (e.g., quality of life) after discharge.

The authors were not able to perform a meta-analysis of the data because of the substantial heterogeneity in the interventions and study characteristics. In addition, most of the included studies had different goals and did not include thorough descriptions of each intervention component. Therefore, the authors concluded that although many interventions at hospital discharge appear to positively impact the transition to primary care, the available data do not allow them to draw firm conclusions about which interventions are most helpful.

Future research could target the development of a clearer description of the interventions, and attention to care providers' attitudes and training in developing effective handover interventions,” the authors wrote.