Mural vegetations at the site of endocardial trauma in infective endocarditis complicating idiopathic hypertrophic subaortic stenosis

Clinical, Radiographic, and Microbiologic Features of Infective Endocarditis in Patients With Hypertrophic Cardiomyopathy

Infective endocarditis (IE) is an infection of the inner lining of the heart with high morbidity and mortality despite medical and surgical advancements in recent decades. Hypertrophic cardiomyopathy (HC) is one of several medical conditions that have been linked to an increased risk of IE, but there is a paucity of data on this association. We therefore sought to define the clinical phenotype of IE in patients with HC at a single tertiary care center. A retrospective cohort of 30 adult patients with HC diagnosed with IE between January 1, 2006 and December 31, 2016 at Mayo Clinic Rochester were identified. Similar rates of aortic (n = 14) and mitral (n = 16) valve involvement by IE were noted (47% vs 53%). This finding persisted even in patients with left-ventricular outflow tract obstruction and systolic anterior motion of the mitral valve. Symptomatic embolic complications occurred in 10 cases (33%). Surgical intervention was performed in 11 cases (37%). One-year mortality was remarkably low at 7%. In conclusion, in the largest single-center cohort of IE complicating HC, there were similar rates of both mitral and aortic valve involvement regardless of the presence of left ventricular outflow tract obstruction, which is contrary to a long-standing tenet regarding the association of HC and IE. Moreover, no "high risk" IE subset was identified based on HC-related parameters.

Large Mural Vegetation Attached to the Left Ventricular Outflow Tract: A Case Report

We describe an unusual case of staphylococcal endocarditis with vegetation attached to the left ventricular outflow endocardium in a patient with chronic severe aortic regurgitation that was diagnosed by transthoracic echocardiography. There was no involvement of aortic valve endocardium confirmed by transthoracic echocardiography, transesophageal echocardiography, and macroscopically in the operation. This report confirms that chronic endocardial trauma may provide a fertile nidus for the development of bacterial vegetation.

Infective endocarditis in hypertrophic cardiomyopathy: prevalence, incidence, and indications for antibiotic prophylaxis

BACKGROUND

The literature on infective endocarditis in hypertrophic cardiomyopathy (HCM) is virtually confined to case reports. Consequently, the risk of endocarditis in HCM remains undefined.

METHODS AND RESULTS

We assessed the occurrence of endocarditis in 810 HCM patients evaluated between 1970 and 1997. Endocarditis was diagnosed in 10 patients, 2 of whom were excluded from analysis of prevalence and incidence because they were referred for acute endocarditis. At first evaluation, echocardiographic features consistent with prior endocarditis were identified in 3 of 808 patients, a prevalence of 3.7 per 1000 patients (95% CI, 0.8 to 11). Of 681 patients who were followed, 5 developed endocarditis, an incidence of 1.4 per 1000 person-years (95% CI, 0.5 to 3.2); outflow obstruction was present in each of these 5 patients and was associated with the risk of endocarditis (P=0.006). In the 224 obstructive patients, incidence of endocarditis was 3.8 per 1000 person-years (95% CI, 1.6 to 8.9) and probability of endocarditis 4. 3% at 10 years. Left atrial size was also associated with the risk of endocarditis (P=0.007). In patients with both obstruction and atrial dilatation (>/=50 mm), incidence of endocarditis increased to 9.2 per 1000 person-years (95% CI, 2.5 to 23.5). Analysis of all 10 patients with endocarditis identified outflow obstruction in each and atrial dilatation in 7.

CONCLUSIONS

Endocarditis in HCM is virtually confined to patients with outflow obstruction and is more common in those with both obstruction and atrial dilatation. These results indicate that antibiotic prophylaxis is required only in patients with obstructive HCM.

Fatal mural endocarditis and cutaneous botryomycosis after heart transplantation

Fatal mural endocarditis and botryomycosis occurred concurrently in a 62-year-old women 4 months after orthotopic heart transplantation. Subsequent to mild mitral regurgitation, infection developed on a left atrial thrombus and was complicated by cerebral embolization. Simultaneously, skin nodules manifested on both forearms. Histologic examination revealed typical aspects of early evolving botryomycosis with massive infiltration of the dermis and hypodermis by necrotic granulomas framed by grains of Gram-positive coccoid forms. Bacteria were decorated by a nonspecific polyclonal antibody to Mycobacterium bovis.

Primary left ventricular mural endocarditis diagnosed by transesophageal echocardiography

Primary left ventricular mural abscess was detected by transesophageal echocardiography and was confirmed at necropsy in a 44-year-old woman with Staphylococcus aureus bacteremia and cerebrovascular embolism. In two occasions, transthoracic echocardiography failed to show the mural abscess in this patient. Because of the aggressive nature of primary mural endocarditis, early use of transesophageal echocardiography is recommended in patients with Staphylococcal bacteremia and suspected endocarditis even in the absence of valvular abnormalities detectable by the transthoracic approach.

Severe mitral or aortic valve regurgitation, or both, requiring valve replacement for infective endocarditis complicating hypertrophic cardiomyopathy

Certain clinical and morphologic findings are described in 11 patients with hypertrophic cardiomyopathy complicated by infective endocarditis that produced severe mitral or aortic valve regurgitation, or both, necessitating valve replacement. All 11 patients had changes in the operatively excised valve or valves characteristic of healed infective endocarditis. The infection involved only the mitral valve in seven patients, only the aortic valve in three patients and both valves in one patient. Study of the operatively excised mitral valves indicated that the healed vegetations were located most commonly on the left ventricular aspects of the anterior mitral leaflet, indicating that vegetation had formed at contact points of this leaflet with mural endocardium of the left ventricular outflow tract. In all 11 patients, the infective endocarditis either worsened preexisting valve regurgitation or initiated valve regurgitation and led to worsened signs and symptoms of cardiac dysfunction, necessitating valve replacement. Functional class improved in the nine patients who survived 7 to 101 months after valve replacement. Hypertrophic cardiomyopathy appears to be a factor predisposing to infective endocarditis. Patients with hypertrophic cardiomyopathy should receive prophylactic antibiotic therapy during procedures that predispose to infective endocarditis.

Infectious endocarditis in idiopathic hypertrophic subaortic stenosis: report of three cases and review of the literature

Three cases of infective endocarditis (IE) occurringg in patients with idiopathic hypertrophic subaortic stenosis (IHSS) are described. A review of the literature reveals the IE occurs in about 50 percent of the patients suffering from IHSS. It appears to complicate the natural history of the severe cases, at least as it appears from hemodynamic studies, being precipitated by the same factors and caused by the same infective organisms as in valvular heart disease. It has the same clinical picture and outcome, although the appearance of new murmurs was more common than in other types of heart disease complicated by IE, and indicated the same poor prognosis. The infection seems to involve both the aortic and the mitral valve, with equal frequency, and less commonly the ventricular outflow tract. The need for IE prophylaxis in cases of IHSS is stressed.