The patient was diagnosed with aortic root abscess ruptured into the right atrium and hence aorto-right atrial fistula. Unfortunatley the patient developeed a picture of disseminated intra vascular coagulation with a dramatic drop in platelets and fibrinogen and had sudden death before any surgical intervention.
Discussion: In a large retrospective multi-centre study over 4681 episodes of infective endocarditis (IE), a total of 76 patients with aorto-cavitary fistula (1.6%) diagnosed by echocardiography or during surgery were identified. Fistulae were found in 1.8% of cases of native valve IE and in 3.5% of cases of prosthetic valve IE (PVE) from the general population and in 0.4% of drug abusers. PVE was present in 31 (41%) cases of aorto-cavitary fistula. Trans- thoracic and transoesophageal echocardiography detected the fistulous tracts in 53 and 97% of cases, respectively. Peri-annular abscesses were detected in 78% of cases; fistulae originated in similar rates from the three sinuses of Valsalva, and the four cardiac chambers were equally involved in the fistulous tracts. Fistula formation occurred only in aortic valve IE and was more frequent in prosthetic aortic than in native aortic valve endocarditis (5.8 vs. 3.6%, P < 0.04). All patients had aortic valve involvement and multi- valvular infection occurred in one-third of patients (30%). The majority of patients had peri-annular abscesses (78% of patients) with a median maximal diameter of 12 mm. Abscesses larger than 10 mm were detected in 42% of cases and an associated ventricular septal defect was present in 20% of cases. Patients with PVE had larger abscesses (58 vs. 31%, P< 0.03).
The site of origin of the fistulous tract was equally distributed between the three sinuses of Valsalva (37, 38, and 25% for right, left, and non-coronary sinuses, respectively). The four cardiac chambers were also equally involved in the fistulous tract.
Complete A-V block was present in 11 patients (14%).
Microbiology: Staphylococci were the most common microorganisms causing 35 (46%) episodes of ACF (coagulase-negative staphylococci in 19 patients, Staphylococcus aureus in 16 patients). Other commonly identified pathogens included streptococci (33%) and enterococci (5%) and no pathogen was identified in five patients (7%). There were three cases of fungal endocarditis and polymicrobial infection was documented in two cases (one case of S. aureus-Candida albicans and one case of Klebsiella pneumonia-Candida turulopsis). S. aureus was more frequent in NVE than in PVE (29 vs. 10%, respect- ively, P 1⁄4 0.05), whereas coagulase-negative staphylococci were more common in PVE than in NVE (48 vs. 9%, respectively, P 1⁄4 0.001).
Sixty-six patients (87%) underwent surgical treatment . The mean time interval from diagnosis of ACF to surgery was 4.5 days. In-hospital mortality among the 76 patients was 41%. Among the 66 surgical patients there were 28 deaths (42%). Causes of death in surgically treated patients were multi-organ failure (n 1⁄4 8), septic shock (n 1⁄4 7), cardiogenic shock (n 1⁄4 6), and post-operative haemorrhagic shock.
A total of 10 patients did not undergo surgical treatment. Three patients died before planned surgical intervention because of cardiogenic shock (one patient), uncontrolled infection (one patient), and sudden death in another patient. Conservative treatment was decided in seven patients because of excessive co-morbid surgical risk.
Conclusion: Aorto-cavitary fistulous tract formation is an uncommon but extremely serious complication of IE. In-hospital mortality was exceptionally high despite aggressive management with surgical intervention in the majority of patients. Prosthetic IE, urgent surgery, and the development of HF identify the subgroup of patients with IE and ACF that have significantly increased risk of in-hospital death.
Transesophageal Echocardiography was more effective than transthoracic Echocardiography in detecting this type of complication.
Reference: Anguera I, Miro JM, Vilacosta I et al. Aorto-cavitary fistulous tract formation in infective endocarditis: clinical and echocardiographic features of 76 cases and risk factors for mortality. Eur Heart J 2005;26:288–297