Much is known about the prevalence, treatment, and prognosis of acute myocardial infarction (AMI) when it occurs in the community and is the presenting diagnosis. Few studies, however, have addressed the epidemiology of in-hospital AMIs. This study by Maynard and colleagues attempts to elucidate the basic epidemiologic characteristics, treatments, and outcomes of patients who suffer in-hospital AMIs.
This retrospective cohort consisted of 7,054 patients who had been discharged with a diagnosis of AMI from 127 Veterans Health Administration (VHA) medical centers between July and August 2003. Patients who had suffered a postoperative MI or were transferred in from another hospital were excluded. Data was obtained from both the electronic and paper medical records. Of the 7,054 patients in the study, 792 (11.2%) had experienced an AMI while hospitalized for other medical problems. These 792 patients were older by approximately 4.5 years and more frequently suffered from heart failure, diabetes, chronic renal insufficiency, COPD, cerebrovascular disease, dementia, and cancer. These patients were less likely, however, to have had a previous MI, to be current smokers, or to have undergone previous angioplasty. They were also less likely to have known lipid disorders or to be taking aspirin or lipid-lowering agents.
Regarding their presentations and management, the patients who suffered in-hospital AMIs had faster heart rates and lower blood pressures. They were also up to 75% less likely to report typical symptoms of cardiac ischemia, including chest pain/pressure, shoulder pain, nausea, and diaphoresis. They were less often seen by an attending cardiologist and had more contraindications to AMI therapy; thus, these patients underwent reperfusion therapy at much lower rates, both initially and at 30 days. Their troponin levels were more frequently elevated, but they were only half as likely to have ST segment elevations at the time of diagnosis. Hospitalizations were longer for the in-hospital group, and there were higher rates of in-hospital cardiogenic shock, cardiac arrest, and death (27.3% versus 8.6%). The 30-day mortality rate was also higher (33% versus 11.9%). Multivariate logistic regression revealed an adjusted odds ratio of 2.0 (95% confidence interval 1.7 to 2.4; p<0.001) for 30-day mortality in those who experienced an in-hospital AMI versus those who presented with an AMI.
Potential reasons for the increased severity of outcomes include, but are not limited to, their many chronic comorbidities, their other acute diagnoses, the failure of the medical team to recognize cardiac ischemia in a timely manner (i.e., higher initial troponins), the inability to treat MIs appropriately secondary to contraindications to acute intervention, and the lack of an attending cardiologist presiding over their medical care. Clearly, further studies are needed to elucidate the causes of death in the 33% of patients who died, because it is unclear whether the patients died of complications from their MIs or as a result of their multiple other medical problems. Knowledge of the extent to which these patients could be managed, both medically and via interventional procedures (and why these therapies were not pursued), would also be of value.
This study emphasizes the importance of recognizing atypical presentations of AMIs and exercising vigilance in pursuing the most aggressive therapy possible, as dictated by a patient’s ability to tolerate medical and procedural interventions.
Hyperglycemia in Heart Failure
By David H. Wesorick, MD
Barsheshet A, Garty M, Grossman E, et al. Admission blood glucose level and mortality among hospitalized nondiabetic patients with heart failure. Arch Intern Med. 2006 Aug 14-28;166(15):1613-1619.
The medical literature strongly suggests that inpatient hyperglycemia is associated with a variety of poor outcomes. Little is known, however, about the relationship between hyperglycemia and heart failure. These investigators examined the association of admission blood glucose and mortality in patients who were admitted to the hospital with acute heart failure.