(P038) RELATIONSHIP BETWEEN PARAMETERS DEFINING CARDIOGENIC SHOCK AND OUTCOME IN PATIENTS WITH ST-ELEVATION MYOCARDIAL INFARCTION

Background: Despite advances in care, cardiogenic shock (CS) remains the leading cause of death in patients with ST-elevation myocardial infarction (STEMI). One plausible reason we have failed in treating this high-risk cohort effectively may lie in our ability to objectively define CS and intervene timely. Per current guidelines, CS is defined as either (1) systolic blood pressure (SBP) ≤ 90mmHg, (2) cardiac-index (CI) < 1.8 L/min/m2 or < 2.2 L/min/m2 in presence of inotropic/vasopressor therapy or (3) lactate >2 mmol/L; these parameters are used interchangeably. We aim to examine the incidence of CS based upon each of these parameters in STEMI patients, before and after primary percutaneous coronary intervention (PPCI), and identify their relationship with adverse outcome.

METHODS AND RESULTS:

Methods: Consecutive STEMI patients confirmed by electrocardiogram and coronary angiography were prospectively recruited at their presentation to the cardiac catheterization lab. Continuous hemodynamic monitoring during PPCI was performed using a whole-body impedance-based non-invasive technology. SBP and lactate were measured pre- and post-PPCI. An adverse outcome was defined as hospital stay >4 days and/or death at 30 days.

204 patients (mean age 65.9; 60/204 (30%) female) were recruited. Pre-PPCI, the incidence of CS was highest based on lactate criteria (29%) when compared to CI (16%) and SBP (8.5%). The incidence of CS decreased post-PPCI based on lactate and CI but did not differ based on SBP criterion. 44 /204 (21.6%) patients had adverse outcomes [7 (3.43%) death at 30-day and 42 (20.6%) in-hospital stay >4 days]. As described in Figure 1, the patients who met adverse outcomes were noted to have higher lactate level and lower CI for a similar SBP in comparison to the ones who had an uneventful course. Despite an improving trend, a discordant relationship between the CS defining parameters existed even post-PPCI. Patients experiencing adverse outcomes were noted to have lower SBP, CI and higher lactate levels pre-PPCI however, post-PPCI, they were only noted to have lower CI and higher CI, but similar SBP (Table 1).

Conclusion: Our study describes: (1) poor congruity between the parameters defining cardiogenic shock, (2) low CI and high lactate at presentation and failure in their normalization are associated with adverse outcomes, and (3) confirms that SBP is a poor surrogate for CI in STEMI patients. Currently, we are working on building on the above findings by characterizing how various hemodynamic parameters are associated with other in-hospital, 30-day, and one-year outcomes in STEMI patients.