Acute MI as a Complication of GI Bleeding
Acute MI as a Complication of GI Bleeding
Abstract & Commentary
Synopsis: Acute MI is common among patients admitted to an ICU for acute GI hemorrhage, particularly among patients who are middle-aged or older and those with two or more risk factors for coronary artery disease.
Source: Emenike E, et al. Mayo Clin Proc 1999; 74:235-241.
Bhatti and colleagues at bridgeport hospital in Connecticut previously reported in a retrospective chart review that 14% of patients admitted to their ICU with acute gastrointestinal (GI) hemorrhage met criteria for the diagnosis of an acute myocardial infarction (MI) during the hospitalization (Bhatti N, et al. Chest 1998;114:1137-1142). To test the hypotheses generated from that retrospective study, Emenike and colleagues performed the present prospective observational study of all patients admitted to the ICU with a primary diagnosis of GI hemorrhage during a subsequent nine-month period. A 16-part data collection was carried out on all such patients to gain a more comprehensive picture of the severity and physiological effect of their GI bleed, to assess risk factors for coronary artery disease, and to seek evidence for MI. Electrocardiograms and serial cardiac enzyme results were interpreted by a cardiologist not otherwise involved in the study.
Seventy-eight patients ranging in age from 26 to 91 years (mean, 65 years; median, 67 years) were admitted to the ICU a total of 83 times during the study period. Their mean admission APACHE II scores were 15.7 ± 0.8, range 5-40. Sixteen admissions (19%) resulted in the death of the patient during the hospitalization; in five of these, GI bleeding was the direct cause of death. Eleven patients (13% of admissions) met criteria for an acute MI. Of these, only one complained of chest pain. An additional 10 patients had electrocardiographic evidence of myocardial ischemia but no enzymatic evidence of MI. Patients with MI were older (74.4 vs 61.7 years; P < 0.05), had higher APACHE II scores (21.6 vs 14.6; P < 0.05), and had more cardiac risk factors (2.3 vs 1.4; P < 0.05) than those without MI, and they also had longer stays in the ICU (8.6 vs 3.3 days; P < 0.05) and in the hospital (16.3 vs 9.1 days; P < 0.05). Having an MI in association with the GI hemorrhage was not an independent risk factor for in-hospital mortality (risk ratio, 1.5, 95% CI, 0.5-4.4). There were no differences between patients with and without MI with respect to lowest hematocrit, lowest blood pressure, or heart rate.
Comment by David J. Pierson, MD, FACP, FCCP
This study confirms the hypothesis that acute MI occurs commonly (13% of admissions) in patients with GI hemorrhage admitted to an ICU. In most instances, MI was clinically silent. Patients with MI had longer ICU and hospital stays than patients who did not develop an MI during hospitalization, although whether this might have been predictable independently of the MI on the basis of data available on admission such as age, APACHE II score, and cardiac risk factors is not known.
The main limitation of this study, acknowledged by Emenike et al, is the fact that only patients admitted to the ICU, who represented about 40% of all patients admitted with acute GI hemorrhage during the study period, were included. Thus, the generalizability of the findings depends on the criteria used by the physicians involved in deciding who could "go to the floor" and who should be watched in the ICU. Unfortunately, although realistically in terms of clinical practice in a community hospital, no fixed ICU admission criteria were used.
Another limitation is that all patients with GI bleeding had enzymatic and electrocardiographic evidence for acute MI specifically sought, but patients admitted during the same period with other diagnoses presumably did not. An MI incidence of 13% seems high, although whether it is higher than that in Emenike et al’s patients with other ICU admission diagnoses but with similar demographics and cardiac risk factors was not determined. The possible relevance of this question is emphasized by the fact that most patients with MI reported no symptoms suggestive of this diagnosis. Others have reported that only about 6% of critically ill patients in the ICU have otherwise unsuspected MIs (Guest TM, et al. JAMA 1995;273:1945-1949), so it seems reasonable to assume that acute GI bleeding, particularly in older patients with cardiac risks, predisposes to this condition.
Its limitations notwithstanding, this study should remind us that patients admitted to the ICU with an acute problem in one organ system often turn out to have unsuspected but clinically important problems in other organs as well. We are tuned in to nosocomial pneumonia, thromboembolism, and catheter-associated infections, but we should also be aware that potentially fatal cardiac events may occur as well, even in the absence of specific symptoms.
Patients admitted to the ICU with GI bleeding who also have acute MI:
a. complain of chest pain in most instances.
b. have increased ICU and hospital lengths of stay.
c. have a mortality rate in the hospital of 39%.
d. have significantly lower minimum hematocrits than those who do not develop MI.
e. All of the above
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