Killip class

The Killip classification is a system used in individuals with an acute myocardial infarction (heart attack), in order to risk stratify them. Individuals with a low Killip class are less likely to die within the first 30 days after their myocardial infarction than individuals with a high Killip class. [Killip T, Kimball JT. " [http://www.ncbi.nlm.nih.gov/pubmed/6059183?ordinalpos=4&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum Treatment of myocardial infarction in a coronary care unit: a two year experience of 250 patients.] " Am J Cardiol 1967; 20: 457-464 . ISSN 0002-9149]

The study

The study was a case series with unblinded, unobjective outcomes, not adjusted for confounding factors, nor validated in an independent set of patients. The setting was the coronary care unit of a university hospital in the USA.

250 patients were included in the study (aged 28 to 94; mean 64, 72% male) with a myocardial infarction. Patients with a cardiac arrest prior to admission were excluded.

Patients were ranked by Killip class in the following way:
*Killip class I includes individuals with no clinical signs of heart failure.
*Killip class II includes individuals with rales or crackles in the lungs, an S₃ gallop, and elevated jugular venous pressure.
*Killip class III describes individuals with frank acute pulmonary edema.
*Killip class IV describes individuals in cardiogenic shock or hypotension (measured as systolic blood pressure lower than 90 mmHg), and evidence of peripheral vasoconstriction (oliguria, cyanosis or sweating).

Conclusions

Within a 95% confidence interval the patient outcome was as follows:
*Killip class I: 81/250 patients; 32% (27 to 38%). Mortality rate was found to be at 6%.
*Killip class II: 96/250 patients; 38% (32 to 44%). Mortality rate was found to be at 17%.
*Killip class III: 26/250 patients; 10% (6.6 to 14%). Mortality rate was found to be at 38%.
*Killip class IV: 47/250 patients; 19% (14 to 24%). Mortality rate was found to be at 81%.

The Killip-Kimball classification has played a fundamental role in classic cardiology, having been used as a stratifying criteria for many other studies. Worsening Killip class has been found to be independently associated with increasing mortality in several studies.

Killip class 1 and no evidence of hypotension or bradycardia, in patients presenting with acute coronary syndrome, should be considered for immediate IV betablockade.

References