. "According to the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) we defined comorbidities and postoperative complications including hypertension (ICD-9-CM 401???405), chronic obstructive pulmonary disease (ICD-9-CM 490???496), diabetes mellitus (ICD-9-CM 250), stroke (ICD-9-CM 430???438), acute myocardial infarction (ICD-9-CM 410), congestive heart failure" . . .