Echocardiographic Killip Classification

Background: The Killip classification is a well-recognized clinical assessment tool for heart failure in patients presenting with acute coronary syndromes. We hypothesized that an echocardiographic correlate of this classification, using diastolic grade and stroke volume index (SVI) as indicators of pulmonary congestion and systemic perfusion respectively, could be a useful risk stratification tool among all patients.

Methods: We included all consecutive patients in sinus rhythm evaluated by our research echo technicians and reviewed by a single senior cardiologist in Tel-Aviv Medical Center between 01/2013 to 12/2015. Echocardiographic killip (eKillip) class was defined according to diastolic grade and SVI, with levels above 35ml/m² considered normal. Patients with a normal filling pressure (normal diastolic function or impaired relaxation) and normal SVI were defined as eKillip class-1. Patients with pseudo-normal or restrictive diastolic patterns and a normal SVI were ascribed to eKillip class-2 or 3, respectively. Those with pseudo-normal or restrictive diastolic patterns and a sub-normal SVI were defined as eKillip class-4.

Results: The study population comprised 571 patients, mean age was 65±18 and 303(53%) were males. Three hundred and eighty-nine (68%) patients were at eKillip class-1, and 113 (20%), 26(5%) and 43(8%) were ascribed to eKillip classes 2, 3 and 4 respectively. In a univariate logistic regression model, e-Killip class was highly associated with all-cause mortality (p<0.001). In a multivariate binary logistic regression model adjusted to age, gender, renal function, multiple cardio-vascular co-morbidities and malignancy, increasing eKillip class remained associated with all-cause mortality (p=0.02). Compared to patients with eKillip class-1, those at classes 2-4 had 68%, 281% and 385% higher mortality rates, respectively (95% CI 0.80-3.50, 1.00-7.88 and 1.58-9.37, with p=0.17, 0.05 and <0.01, respectively).

Conclusion: Echocardiographic Killip class defined by combination of diastolic grade and SVI among all patients undergoing echocardiography in a tertiary hospital, was significantly associated with all-cause mortality.