Prognostic Utility of Pulmonary Arterial Elastance in Patients With ST-Segment Elevation Myocardial Infarction Classified as Killip Classes 3-4.

Background: Invasive hemodynamic assessment is critical in patients with ST-segment elevation myocardial infarction (STEMI) classified as Killip classes 3-4. However, the prognostic utility of pulmonary arterial elastance (PaE) remains unclear. Methods and Results: We retrospectively analyzed 145 consecutive patients with STEMI classified as Killip classes 3-4 undergoing primary percutaneous coronary intervention, all with complete pulmonary artery catheter data. PaE was calculated as systolic pulmonary artery pressure divided by stroke volume. In total, 27 patients died in hospital (18.6%), and 118 patients (81.4%) survived to discharge. Non-survivors were older, more often women, and had lower estimated glomerular filtration rate and left ventricular ejection fraction than survivors. PaE was significantly higher in non-survivors than in survivors (1.40 vs. 0.81 mmHg/mL, P<0.001). After adjusting for confounders, PaE was independently associated with in-hospital death (P<0.05). In the receiver operating characteristic curve analyses, PaE showed superior discriminative ability (area under the curve [AUC], 0.729) than pulmonary vascular resistance (AUC, 0.648) and pulmonary arterial pulsatility index (PAPI; AUC, 0.501; both, P<0.05) but was comparable to cardiac power output (AUC, 0.705; P=0.351). Furthermore, the in-hospital mortality rate increased with increasing PaE, consistently across PAPI strata. Conclusions: PaE independently predicts in-hospital death of patients with STEMI classified as Killip classes 3-4. Its robust performance across subgroups and ease of calculation support its use in early risk stratification.