Shock Index More Sensitive Than Cardiogenic Shock in ST-Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

Abstract

a small cohort of patients. 9 Recently, Spyridopoulos et al showed that SI is an independent and stronger predictor of long-term mortality in older patients with STEMI. 10 In that study, however, an unusual definition of CS (SBP <100 mmHg with HR >100 beats/min) was used, which makes it difficult to compare the results with previous studies and to extrapolate it into daily practice. Furthermore, they did not assess the optimal cut-off for SI, but used a self-chosen cut-off, which was different from previous studies. 8, 9 The independent prognostic value of SI as compared with CS in STEMI treated with primary PCI, is therefore still unclear. The aim of this study was to evaluate the independent impact of SI on 1-year mortality in a large cohort of patients with STEMI (largest until now), treated by primary PCI, and to compare this with CS. MethodsData for this study were collected from the prospective cohort of patients with STEMI at the Isala Hart Centrum, Zwolle, The Netherlands, from January 2000 to December 2011. Patients were diagnosed with STEMI if they had C ardiogenic shock (CS) has previously been shown to be a strong and independent predictor of both short-term and long-term mortality in patients with ST-elevation myocardial infarction (STEMI). 1 Although the incidence of CS in patients with STEMI has declined in the past decades, the mortality due to CS remains high (approximately 50%) despite all advances in management, medication and technology. 2 Early identification of the pre-shock state might play an important role in improving the prognosis of CS in STEMI patients.Several studies in non-cardiac shock patients suggested that shock index (SI), the ratio of heart rate (HR) to systolic blood pressure (SBP), is a sensitive tool for early recognition of septic, hypovolemic or obstructive shock. 3-7 The combination of HR and SBP may be more powerful than either HR or SBP alone, because early stages of shock are also taken into account. Therefore, SI can be a good marker of pre-shock. The predictive importance of SI in patients with STEMI has been shown in a recent study, but that study investigated only short-term mortality, and only 12% of the patients were treated by primary percutaneous coronary intervention (PCI). Background: Cardiogenic shock (CS) is a strong predictor of mortality in patients with ST-elevation myocardial infarction (STEMI), but there is evidence that shock index (SI), taking into account both blood pressure and heart rate, is a more sensitive and powerful predictor. We investigated the independent impact of SI and CS on 30-day and 1-year mortality in patients with STEMI, treated by primary percutaneous coronary intervention (PCI).

The prognostic value of shock index for the outcomes of acute myocardial infarction patients

“…Three studies evaluated the influence of high SI on the prognosis in 14,759 STEMI patients. [ 7 , 9 , 11 ] Adverse outcomes (all-cause mortality or MACE) were significantly higher in the high SI group compared with the low SI group (pooled RR = 1.93, 95% CI: 1.10–3.39, P = .02; I 2 = 95%) (Fig. 3 ).…”

“…Of the 8 studies, 2 showed only in-hospital mortality, [ 6 , 13 ] 2 reported only short-term adverse outcomes, [ 7 , 9 ] 2 assessed only long-term MACE, [ 10 , 12 ] 1 evaluated both in-hospital and long-term mortality, [ 8 ] and 1 measured both short-term and long-term mortality. [ 11 ] Therefore, there were 3, 3, and 4 studies for the analyses of in-hospital mortality, short-term, and long-term adverse outcomes, respectively.…”

“…[ 18 ] SI, a sample algorithm, has been shown to be more sensitive than cardiogenic shock. [ 11 ] The sensitive value of SI may help detect the pre-shock AMI patients earlier to improve the prognosis.…”

“…Although more and more studies have revealed the prognostic value of elevated SI in the AMI patients, the quality of the studies vary widely. [ 6 , 7 , 10 , 11 , 13 ] Up to now, there has been no systematic review to evaluate the relationship between elevated SI and the in-hospital, short-term, and long-term adverse outcome, respectively. Therefore, we conducted a systematic review and meta-analysis of clinical trials to determine the effect of high SI on the prognosis of AMI patients.…”

Derivation and Validation of Shock Index as a parameter for Predicting Long-term Prognosis in Patients with Acute Coronary Syndrome

“…The association between SI and greater in-hospital mortality risk in patients with NSTEMI has also been confirmed 19 , and elevated SI also correlates with a poorer 5-year prognosis in patients with AMI undergoing PCI 20 . In most of these studies, SI values of<0.7 are considered normal 12 , 14 , 16 , 18 , 19 . We hypothesized that SI could predict long-term prognosis in ACS patients undergoing PCI and that it can identify those patients who are at high risk of adverse cardiac events.…”