Advertisement

Risk stratification vs routine intensive care stay in non ST segment elevation myocardial infarction (NSTEMI)

Published:April 13, 2020DOI:https://doi.org/10.1016/j.ejim.2020.04.011

      Keywords

      Non-ST-segment-elevation acute coronary syndromes (NSTE ACS) encompass a wide spectrum of clinical conditions characterised by acute ischemic symptoms, electrocardiographic signs of myocardial ischemia (which may or may not be evident), and elevation of the biochemical markers of myocardial injury: when troponin values are within normal range, the case will be defined as unstable angina, if this clinical entity has not been declared deceased after the introduction of high-sensitivity troponin measurements [
      • Braunwald E
      • Morrow DA
      Unstable Angina. Is It Time for a Requiem?.
      ]. All three components of the syndrome may allow immediate risk stratification almost invariably in the emergency room [
      • Braunwald E
      Unstable angina. A classification.
      ,
      • Savonitto S
      • Ardissino D
      • Granger CB
      • et al.
      Prognostic value of the admission electrocardiogram in acute coronary syndromes. Results from the GUSTO-IIb trial.
      ,
      • Savonitto S
      • Fusco R
      • Granger CB
      • et al.
      Immediate risk stratification of acute coronary syndromes in the emergency room. The prognostic value of clinical data, electrocardiography and biochemical markers.
      ,
      • Thygesen K
      • Alpert JS
      • Jaffe AS
      • et al.
      Executive Group on behalf of the Joint European Society of Cardiology (ESC)/American College of Cardiology (ACC)/American Heart Association (AHA)/World Heart Federation (WHF) Task Force for the Universal Definition of Myocardial Infarction. Fourth Universal Definition of Myocardial Infarction (2018).
      ]. From a clinical standpoint, this simple clinical approach, and existing Guidelines [
      • Amsterdam EA
      • Wenger NK
      • Brindis RG
      • et al.
      2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.
      ,
      • Roffi M
      • Patrono C
      • Collet JP
      • et al.
      2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation: Task Force for the Management of Acute Coronary Syndromes in Patients Presenting without Persistent ST-Segment Elevation of the European Society of Cardiology (ESC).
      ], should assist the attending physician in allocating each individual patient to the most appropriate pattern of care, including the opportunity and timing of invasive treatment and the admission to intensive care units (ICU) vs ward. Other readily available clinical and laboratory data, such as age, comorbidities, blood hemoglobin and serum creatinine allow immediate stratification of the iathrogenic risk of drug and interventional therapies [
      • Savonitto S
      • Morici N
      • De Servi S
      Treatment of acute coronary syndromes in the elderly and in patients with comorbidities.
      ]. A few mortality risk prediction scores have been derived from clinical trials and registries: among these, the ESC Guidelines recommend the GRACE score [
      • de Araujo Goncalves P
      • Ferreira J
      • Aguiar C
      • Seabra-Gomes R
      TIMI, PURSUIT, and GRACE risk scores: sustained prognostic value and interaction with revascularization in NSTE-ACS.
      ], also available as an online risk calculator (http://www.gracescore.org/WebSite/default.aspx?ReturnUrl=%2f). These scores are mostly focused on the ischemic risk, while providing little assistance for a comprehensive estimation of risk vs benefit of the whole clinical process of patient care.
      In a recent issue of the European Journal of Internal Medicine, Patrìcia Guimarães and colleagues, from Samaritano Paulista Hospital, Sao Paulo, Brazil, reported on the characteristics and clinical outcomes of 1263 NSTEMI patients admitted to their hospital from 2014 to 2018 [
      • Guimarães PO
      • Sampaio MC
      • Malafaia FL
      • et al.
      Clinical outcomes and need for intensive care after non-ST-segment elevation myocardial infarction.
      ]. The mean patient age was 62 years. Almost 95% of the patients were admitted to the ICU, as per routine at their hospital. The authors retrospectively defined complications requiring ICU care as cardiac arrest, cardiogenic shock, stroke, re-infarction, heart block requiring pacemaker placement, respiratory failure, sepsis or death. By using the Acute Coronary Treatment and Intervention Outcomes Network (ACTION) ICU risk score (which, however, was developed from a Medicare database of patients aged ≥65 years) [
      • Fanaroff AC
      • Chen AY
      • Thomas LE
      • et al.
      Risk score to predict need for intensive care in initially hemodynamically stable adults with non-ST-segment-elevation myocardial infarction.
      ], they also aimed to retrospectively identify NSTEMI patients who might not have needed ICU admission. The ACTION ICU risk score uses 9 variables on admission to predict the likelihood that an initially stable patients with NSTEMI will develop a complication requiring ICU-level care [
      • Fanaroff AC
      • Chen AY
      • Thomas LE
      • et al.
      Risk score to predict need for intensive care in initially hemodynamically stable adults with non-ST-segment-elevation myocardial infarction.
      ]. As shown in the Figure 1, the score is dominated by signs of heart failure, with the sum of symptoms, high heart rate and low systolic blood pressure accounting for 66% of the predictive information of the multivariable model. On the other hand, elevated troponin and ischemic ECG changes, though predictive of complications, were much less informative. At Samaritano Paulista Hospital, 70 percent of the patients had an ACTION ICU score of ≤5, thus being at low risk, 92 percent underwent coronary angiography, and 57 percent revascularization. Complications were more common among older patients or those with higher levels of serum creatinine. The C-statistics for the ACTION risk score to predict complications in this patient sample was 0.55, that is much lower than the 0.72 of the original publication to which the same authors had been contributing with their patients.
      Figure 1
      Figure 1Independent predictors of in-hospital development of complications requiring ICU care (defined as cardiac arrest, shock, high-grade atrioventricular block, respiratory failure, stroke, or death). These variables are the components of the Acute Coronary Treatment and Intervention Outcomes Network (ACTION) ICU risk score
      [
      • Fanaroff AC
      • Chen AY
      • Thomas LE
      • et al.
      Risk score to predict need for intensive care in initially hemodynamically stable adults with non-ST-segment-elevation myocardial infarction.
      ]
      . Figures represent the percent predictive information accounted in the model by each variable, calculated as the proportion of the individual Χ2 compared to the sum of all X2. aAnalysed as continuous variable: heart rate per 5 bpm; systolic BP per 10 mmHg; serum creatinine per 1 mg/dL; troponin per 5 x ULN. bvs T-wave inversion or transient ST-segment elevation, or none.
      Both the original ACTION ICU score publication [
      • Fanaroff AC
      • Chen AY
      • Thomas LE
      • et al.
      Risk score to predict need for intensive care in initially hemodynamically stable adults with non-ST-segment-elevation myocardial infarction.
      ] and the Samaritano Paulista data provide insight on the current management of NSTEACS. Both of them confirm the wide spectrum of clinical complexity in NSTEACS, ranging from very low-risk to very high risk of in-hospital complications. The Samaritano Paulista data confirm that when a systematic invasive approach is used, “ischemic” variables (such as ST depression on the ECG and elevated troponin levels) are much less important than heart failure variables or markers of systemic impairment, such as serum creatinine levels. These latter variables should be properly considered as the current gatekeepers of ICU admission, where advanced ventilation and renal replacement therapies can be provided on time to prevent further deterioration. Multiorgan failure is not exceptional in NSTEMI complicated by cardiogenic shock and is associated with high mortality [
      • Vallabhajosyula S
      • Dunlay SM
      • Prasad A
      • et al.
      Acute Noncardiac Organ Failure in Acute Myocardial Infarction With Cardiogenic Shock.
      ], and the modern ICU should be equipped to support multiorgan failure, as indicated by specific Consensus Documents [
      • Bonnefoy-Cudraz E
      • Bueno H
      • Casella G
      • et al.
      Acute Cardiovascular Care Association Position Paper on Intensive Cardiovascular Care Units: An update on their definition, structure, organisation and function.
      ].
      The in-hospital and long-term outcome of NSTEACS has dramatically improved using a systematic invasive approach, even in elderly patients [
      • Morici N
      • Savonitto S
      • Ferri LA
      • et al.
      for the Elderly ACS 2 Investigators. Outcomes of elderly patients with ST-elevation or non-ST-elevation acute coronary syndrome undergoing percutaneous coronary intervention.
      ]. As commented on by Patrìcia Guimarães and colleagues in their paper, “depending on bed availability” NSTEMI patients are still being often admitted to the ICU, and this is mostly a “political” choice. However, besides the cost of this approach [
      • van Diepen S
      • Tran DT
      • Ezekowitz JA
      • et al.
      The high cost of critical care unit overutilization for patients with NSTE ACS.
      ], which may vary across different health care systems, restricting all NSTEMI patients in a ICU bed has a number of untoward effects, whereas a ward with telemetry and avoidance of costricted bedrest may be safer, allowing less anticoagulation and muscle deconditioning, issues that are not captured by most scores. Being aware of this risk-stratified patient management within the wide spectrum of ACS (including the uncomplicated STEMI cases managed by primary angioplasty), also allows prompt shift of “routine” medical practices to face real emergencies, as in response to the current COVID-19 outbreak in Lombardy – Italy, where in a matter of just a few days the whole regional emergency system had to be rearranged to increase the number of ICU beds dedicated to patients in need of mecanical ventilation [
      • Grasselli G
      • Pesenti A
      • Cecconi M
      Critical Care Utilization for the COVID-19 Outbreak in Lombardy, Italy: Early Experience and Forecast During an Emergency Response.
      ]. In these days, the network for time-dependent emergencies, such as STEMI and stroke was completely rearranged, placing most patients in subintensive beds, using the data provided by two decades of experience with risk stratification across the ACS spectrum.

      Funding

      None

      Declaration of Competing Interest

      None

      References

        • Braunwald E
        • Morrow DA
        Unstable Angina. Is It Time for a Requiem?.
        Circulation. 2013; 127: 2452-2457
        • Braunwald E
        Unstable angina. A classification.
        Circulation. 1989; 80: 410-414
        • Savonitto S
        • Ardissino D
        • Granger CB
        • et al.
        Prognostic value of the admission electrocardiogram in acute coronary syndromes. Results from the GUSTO-IIb trial.
        JAMA. 1999; 281: 707-713
        • Savonitto S
        • Fusco R
        • Granger CB
        • et al.
        Immediate risk stratification of acute coronary syndromes in the emergency room. The prognostic value of clinical data, electrocardiography and biochemical markers.
        Ann Noninv Electrocardiol. 2001; 6: 64-77
        • Thygesen K
        • Alpert JS
        • Jaffe AS
        • et al.
        Executive Group on behalf of the Joint European Society of Cardiology (ESC)/American College of Cardiology (ACC)/American Heart Association (AHA)/World Heart Federation (WHF) Task Force for the Universal Definition of Myocardial Infarction. Fourth Universal Definition of Myocardial Infarction (2018).
        Circulation. 2018 Nov 13; 138: e618-e651
        • Amsterdam EA
        • Wenger NK
        • Brindis RG
        • et al.
        2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.
        Circulation. 2014; 130: 2354-2394
        • Roffi M
        • Patrono C
        • Collet JP
        • et al.
        2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation: Task Force for the Management of Acute Coronary Syndromes in Patients Presenting without Persistent ST-Segment Elevation of the European Society of Cardiology (ESC).
        Eur Heart J. 2016; 37: 267-315
        • Savonitto S
        • Morici N
        • De Servi S
        Treatment of acute coronary syndromes in the elderly and in patients with comorbidities.
        Rev Esp Cardiol. 2014; 67: 564-573
        • de Araujo Goncalves P
        • Ferreira J
        • Aguiar C
        • Seabra-Gomes R
        TIMI, PURSUIT, and GRACE risk scores: sustained prognostic value and interaction with revascularization in NSTE-ACS.
        Eur Heart J. 2005; 26: 865-872
        • Guimarães PO
        • Sampaio MC
        • Malafaia FL
        • et al.
        Clinical outcomes and need for intensive care after non-ST-segment elevation myocardial infarction.
        Eur J Intern Med. 2020; https://doi.org/10.1016/j.ejim.2020.02.008
        • Fanaroff AC
        • Chen AY
        • Thomas LE
        • et al.
        Risk score to predict need for intensive care in initially hemodynamically stable adults with non-ST-segment-elevation myocardial infarction.
        J Am Heart Assoc. 2018; 7e008894https://doi.org/10.1161/JAHA.118.008894
        • Vallabhajosyula S
        • Dunlay SM
        • Prasad A
        • et al.
        Acute Noncardiac Organ Failure in Acute Myocardial Infarction With Cardiogenic Shock.
        J Am Coll Cardiol. 2019; 73: 1781-1791
        • Bonnefoy-Cudraz E
        • Bueno H
        • Casella G
        • et al.
        Acute Cardiovascular Care Association Position Paper on Intensive Cardiovascular Care Units: An update on their definition, structure, organisation and function.
        Eur Heart J Acute Cardiovasc Care. 2018; 7: 80-95
        • Morici N
        • Savonitto S
        • Ferri LA
        • et al.
        for the Elderly ACS 2 Investigators. Outcomes of elderly patients with ST-elevation or non-ST-elevation acute coronary syndrome undergoing percutaneous coronary intervention.
        Am J Med. 2019; 132: 209-216
        • van Diepen S
        • Tran DT
        • Ezekowitz JA
        • et al.
        The high cost of critical care unit overutilization for patients with NSTE ACS.
        Am Heart J. 2018; 202: 84-88
        • Grasselli G
        • Pesenti A
        • Cecconi M
        Critical Care Utilization for the COVID-19 Outbreak in Lombardy, Italy: Early Experience and Forecast During an Emergency Response.
        JAMA. 2020; (Published online March 13)https://doi.org/10.1001/jama.2020.4031