Reviewing the AHA prophylaxis guidelines on infective endocarditis prevention in a teaching hospital from 2007-2015
Author(s):
Hoi Yee Annie Lo; Anahita Mostaghim; Nancy Khardori
Background:
Pre-procedure infective endocarditis (IE) prophylaxis guidelines were narrowed in 2007 by the American Heart Association (AHA). Studies on the effects of the revised guidelines on Viridans group Streptococci (VGS) IE are conflicting. This retrospective review of IE at a tertiary-care teaching hospital aims to determine the association of specific procedures and risk classes with the causative organisms of IE.
Hypothesis:
The revised AHA guidelines adequately cover high risk patients for IE prophylaxis.
Methods:
Admissions from 2007-2015 were identified with IE-related ICD-9 codes. Cases that met Modified Duke Criteria for IE and also underwent a procedure in the prior 6 months were analyzed. Cases were divided into three groups: patients meeting AHA defined cardiac risk factors (history of IE, prosthetic cardiac valves, congenital cyanotic heart disease, and cardiac transplants with valvulopathy) for IE prophylaxis (Group A), patients with other valvular/structural cardiac diseases not meeting AHA characteristics (Group B), and those without either (Group C). Three types of procedures were studied in each group, including dental/respiratory (recommended for prophylaxis), invasive gastrointestinal/
Results:
363 admissions met criteria for definite endocarditis and 133 had a procedure in the prior 6 months. Group A had 49 cases, Group B had 39, and Group C had 45 cases. For the dental/respiratory procedures, Group B was more likely to have VGS IE than Group A (OR=40, P=0.016) but same as Group C (OR=2, P=0.624). For GI/GU procedures, all groups were equally likely to have IE caused by gut pathogens. IE caused by staphylococci species did not differ among the groups. Group C was more likely to develop methicillin resistant (MR) staphylococcal IE than group A (OR=4, P=0.041). The overall 30 day mortality was highest in group A, followed by group B and C. However, for patients in group A and B, mortality was higher for those who underwent a procedure in the preceding 6 months.
Conclusions:
Patients in group A who underwent any procedure had the highest mortality related to IE. All patients in group B that underwent a dental/respiratory procedure developed VGS IE. This data indicates that antibiotic prophylaxis before a dental/respiratory procedure should be extended to include this group of patients. All patients who underwent a vascular surgery had higher percentages of staphylococcal IE than those who underwent other procedures, with group C having a predilection to developing MR staphylococcal IE.