Tricuspid infective endocarditis: 56 cases.

Fifty six cases of tricuspid infective endocarditis (TIE) were seen over a period of 15 years. The patients were divided into three groups, on the basis of the site of entry: (a) Thirty one TIE after abortion (6 cases) or in association with drug addiction (25 cases) are characterized by the young age of the patients and the organism (29 staphylococci), the existence of repeated pulmonary emboli and the relatively favourable prognosis (3 deaths). (b) Twelve TIE due to an intravenous infusion catheter (9 cases) or a visceral site of entry: older patients, resistant organisms (3 gram negative bacilli, 8 staphylococci, 5 of which were methicillin-resistant) and with poor prognosis (8 deaths). (c) Thirteen TIE where the site of entry was unidentified, running a sub-acute course, 7 due to streptococci, and often associated with involvement of the left side of the heart, which was the dominant prognostic feature (6 deaths). Mortality was 30%. Of predominant importance in prognosis was the sensitivity of the organism: 6 deaths out of 9 TIE due to methicillin-resistant Staphylococcus aureus and 3 out of 31 TIE due to a sensitive staphylococcus (P less than 0.01). Seventeen underwent surgery. Tricuspidectomy (8 patients) should be reserved for cases of uncontrolled infection. Surgery is not justified by the persistence of pulmonary emboli.