Echocardiographic Killip Classification

Background: Although routine echocardiographic parameters such as ejection fraction are used to risk-stratify for death in patients referred for echocardiography, they have limited predictive value. The authors speculated that noninvasive hemodynamic echocardiographic data, assessing left ventricular filling pressure and output, stratified on the basis of the clinical Killip score, might have additive prognostic value on top of routine echocardiographic parameters. The authors created an echocardiographic correlate of this classification, using diastolic grade and stroke volume index (SVI) as indicators of pulmonary congestion and systemic perfusion, respectively, and evaluated the prognostic value of this correlate. Methods: A retrospective study of consecutive patients (hospitalized or not) referred for echocardiography for a range of cardiac diagnoses in a tertiary medical center. A total of 556 patients in sinus rhythm who were evaluated by two sonographers, and reviewed by a single cardiologist, were included. Normal filling pressure and normal SVI (>35 mL/m²) defined echocardiographic Killip (eKillip) class 1. Patients with pseudonormal or restrictive diastolic patterns and normal SVI were ascribed to eKillip class 2 or 3, respectively. A pseudonormal or restrictive diastolic pattern and a subnormal SVI defined eKillip class 4. Results: eKillip class 1 was present in 382 patients (68%); 115 (20%), 26 (5%), and 42 (7%) patients were in eKillip classes 2 to 4, respectively. Median follow-up time was 1,056 days (interquartile range, 729-1,390 days). A total of 105 deaths occurred. Univariate Cox regression analysis showed that eKillip class was associated with all-cause mortality; hazard ratios (HR) −2.73 (95% CI, 1.67-4.48), 3.19 (95% CI, 1.42-7.17), and 4.79 (95% CI, 2.58-8.89) for each eKillip class above 1 (P < .001). In a multivariate analysis adjusted for the Charlson comorbidity index, eKillip class remained independently associated with all-cause mortality (P = .04). Conclusions: eKillip class was associated with all-cause mortality among all patients undergoing echocardiography at a tertiary hospital.