Prognosis

• NICE note that people with non-ST segment elevation acute coronary syndrome (ACS) have a high incidence of recurrent myocardial ischaemia, a similar long-term outcome to those with ST elevation myocardial infarction (STEMI), and a worse outcome than for people with unstable angina (1)
  • in-hospital death and reinfarction affect 5-10% of patients with ACS
    • despite optimal treatment with anti-ischaemic and antithrombotic drugs, death and recurrent myocardial infarction occur in another 5-10% of patients in the month after an acute episode
  • factors associated with a poorer prognosis include (1)
    • increasing age
    • presence and severity of ECG changes of ischaemia
    • magnitude of rise in biomarkers of myocardial injury (e.g. serum troponin)
    • left ventricular dysfunction, cardiogenic shock
    • tachycardia, arrhythmias (ventricular, atrial fibrillation)
    • renal impairment
    • diabetes mellitus
    • anaemia
    • presence of other cardiovascular disease - cerebrovascular disease, peripheral vascular disease
      
      
• mortality associated with MI increases with age
  
  
• up to 50% of people who have an acute myocardial infarction die within 30 days of the event, and over half of these deaths occur before medical assistance arrives or the patient reaches hospital (2)
  • about one third of all deaths occur within the first hour, usually as the result of an acute fatal arrhythmia
    
    
• prognosis correlates with the degree of myocardial necrosis. Greater degrees of myocardial necrosis are associated with a worse prognosis. The degree of myocardial necrosis can be estimated by various factors - for example (3):
  • rise in serum troponin T
  • degree and extent of ECG changes
  • degree of left ventricular dysfunction on echocardiography
    
    
• CHD death rates are:
  • higher in men than women - CHD related death rates are three times as high as those in women.
  • lower in affluent areas - affluent areas in the UK have CHD death rates that are approximately half of those in deprived area
  • higher in people of South Asian origin (from India, Pakistan, Bangladesh and Sri Lanka)- people of South Asian origin are almost 50% higher than the general UK population
    
    
• prognosis also depends on the timing and nature of intervention; the prognosis is improved with successful early reperfusion, preserved left ventricular function
  • other interventions are associated with prognostic benefit including betablockers, aspirin, statins and ACE inhibitors
  • people who have had a STEMI or an NSTEMI benefit from treatment to reduce the risk of further MI or other manifestations of vascular disease. This is known as secondary prevention
    • since the late 1990s Myocardial Ischaemia National Audit Project (MINAP) has documented the reductions in mortality resulting from changes in acute treatment of MI and the application of secondary prevention measures
      • although 30-day mortality was almost 13% for STEMI in 2003/04, it fell to 8% in 2011/12, with similar falls for NSTEMI

A study investigating one-year mortality following diagnosis of acute coronary syndrome showed (4):

• mortality rate was 3.9% within one year of discharge
  • independent mortality predictors identified (in order of predictive strength):
    • age, lower ejection fraction, poorer EQ-5D quality of life, elevated serum creatinine, in-hospital cardiac complications, chronic obstructive pulmonary disease, elevated blood glucose, male gender, no PCI/CABG after NSTEMI, low haemoglobin, peripheral artery disease, on diuretics at discharge

A study investigating two-year mortality following diagnosis of acute coronary syndrome showed (5):

• mortality rate was 5.5% within two years of discharge
  • independent mortality predictors identified were:
    • age, low ejection fraction, no coronary revascularization/thrombolysis, elevated serum creatinine, poor EQ-5D score, low haemoglobin, previous cardiac or chronic obstructive pulmonary disease, elevated blood glucose, on diuretics or an aldosterone inhibitor at discharge, male sex, low educational level, in-hospital cardiac complications, low body mass index, ST-segment elevation myocardial infarction diagnosis, and Killip class

Data from a large Swedish registry including 108 315 post-MI patients with long-term follow-up revealed a cumulative rate of a cardiovascular composite endpoint (cardiovascular death, recurrent MI, and stroke) of 18.3% in the first year after MI, 9.0% in the subsequent year and 20.0% in the following 3 years (6)

Prognosis with in women without CV risk factors after STEMI

• an analysis of the SWEDEHEART registry showed that women without CV risk factors had the highest mortality risk after STEMI (7)

In-hospital mortality from STEMI is around 9% (8). The rate of sudden death in patients who have had a myocardial infarction is 4 to 6 times the rate in the general population. (9)

References:

1. NICE. Acute coronary syndromes. NICE guideline [NG185] Published: 18 November 2020.
2. NICE. Guidance on the use of drugs for early thrombolysis in the treatment of acute myocardial infarction. [TA52]. Reviewed 2012.
3. Setiadi BM, Lei H, Chang J. Troponin not just a simple cardiac marker: prognostic significance of cardiac troponin. Chin Med J (Engl). 2009 Feb 5;122(3):351-8.
4. Pocock S et al. Eur Heart J Acute Cardiovasc Care. 2015 Dec; 4(6):509-17. Epub 2014 Oct 9.
5. Pocock SJ et al. Predicting two-year mortality from discharge after acute coronary syndrome: An internationally-based risk score. Eur Heart J Acute Cardiovasc Care. 2019 Dec; 8(8):727-737. Epub 2017 Aug 4.
6. Jernberg T et al. Cardiovascular risk in post-myocardial infarction patients: nationwide real world data demonstrate the importance of a long-term perspective. Eur Heart J. 2015;36:1163-1170
7. Figtree GA, Vernon ST, Hadziosmanovic N et al.Mortality in STEMI patients without standard modifiable risk factors: a sex-disaggregated analysis of SWEDEHEART registry data Lancet. 2021 Mar 20;397(10279):1085-1094. doi: 10.1016/S0140-6736(21)00272-5.
8. Jollis JG, Granger CB, Zègre-Hemsey JK, et al. Treatment time and in-hospital mortality among patients with ST-segment elevation myocardial infarction, 2018-2021. JAMA. 2022 Nov 22;328(20):2033-40.
9. Zaman S, Kovoor P. Sudden cardiac death early after myocardial infarction: pathogenesis, risk stratification, and primary prevention. Circulation. 2014 Jun 10;129(23):2426-35.