Evaluating clinical reason and rationale for not delivering reperfusion therapy in ST elevation myocardial infarction patients: Insights from a comprehensive cohort.

BACKGROUND: In ST elevation myocardial infarction (STEMI), reperfusion therapy is lifesaving but is not delivered in approximately one quarter of patients. To address this care gap, we reviewed all STEMI patients that did not receive reperfusion to identify patient characteristics, in-hospital outcomes and the clinical reason or rationale for withholding reperfusion therapy. METHODS: A prospective chart review identified a consecutive cohort of STEMI patients over one-year within a defined health care region with independent data abstraction. Subsequently a trained nurse completed retrospective chart review and categorized patients by rationale for failure to receive reperfusion. RESULTS: Of 745 STEMI patients, 181 (24.3%) did not receive reperfusion. Compared to those receiving reperfusion, they were older (67.5 vs. 58.0years, p=0.001) with more comorbidities and higher in-hospital mortality (15.5% vs. 3.5% p=<0.0001). After excluding 35 patients (unavailable data) there were 146 STEMI patients for qualitative determination. Patient delay greater than 12hours from symptom onset accounted for the majority of patients (56/146, 38.4%). In 19.9% (29/146), conservative medical management with documented rationale occurred. Following angiography, primary PCI was attempted but was unsuccessful or no culprit lesion identified in 19.2% (28/146). The diagnosis of STEMI was missed or no rationale for failure to deliver therapy identified in 8.2% (12/146). Death prior to planned reperfusion occurred in 8 (8/146, 5.5%). CONCLUSIONS: Legitimate rationale exists for the majority of STEMI patients not receiving reperfusion. Ultimately, only 1.6% (12/745) of consecutive STEMI patients failed to receive reperfusion without documented rationale or due to missed diagnosis.

Validity and utility of ICD-10 administrative health data for identifying ST- and non-ST-elevation myocardial infarction based on physician chart review.

BACKGROUND: Health care administrative databases are useful for assessing the population-level burden of disease and examining issues related to access, costs and quality of care. In these databases, the diagnoses and procedures are coded with the use of the World Health Organization International Classification of Diseases (ICD). We examined the validity of 2 ICD-10 coding definitions for categorizing patients with acute myocardial infarction (MI) as having ST-elevation MI (STEMI) or non-ST-elevation MI (non-STEMI). METHODS: Charts of patients with acute MI discharged between April and June 2007 from 3 hospitals in Edmonton, were reviewed to define the acute MI subtype (i.e., STEMI v. non-STEMI). The agreement between clinician chart review and STEMI/non-STEMI classification based on the standard (ICD-10 I21.x) and the supplementary electrocardiogram (ECG) codes (R94.3x) was determined. We assessed the effect of these alternative definitions on in-hospital mortality estimates by applying them to the data for all patients with acute MI admitted to hospital in the province from April 2007 to March 2010. RESULTS: Of the 297 patients, 49.2% were identified as having STEMI based on chart review, 44.4% using the standard definition, and 44.1% using the ECG definition. Both the standard and ECG definitions provided high agreement (92% for STEMI and 100% for non-STEMI) with the chart review classification. In the larger population-level cohort (n = 15 148), use of the standard definition or the ECG definition did not affect in-hospital mortality estimates for patients with STEMI and those with non-STEMI. INTERPRETATION: The standard definition appears equivalent to the definition using supplementary ECG codes to subcategorize patients with acute MI as having STEMI or non-STEMI. These findings may be relevant for the development of later versions of ICD codes.