Multimodality imaging in the diagnosis and management of prosthetic valve endocarditis: A contemporary narrative review

Abstract

Infective endocarditis is one of the leading life-threatening infections around the world. With the exponential growth in the field of transcatheter interventions and advances in specialized surgical techniques, the number of prosthetic valves and cardiac implantable devices has significantly increased. This has led to a steep rise in the number of cases of prosthetic valve endocarditis (PVE) comprising up to 30% of all cases. Clinical guidelines rely on the use of the modified Duke criteria; however, the diagnostic sensitivity of the modified Duke criteria is reduced in the context of PVE. This is in part attributed to prosthesis related artifact which greatly affects the ability of echocardiography to detect early infective changes related to PVE in certain cases. There has been increasing recognition of the roles of complementary imaging modalities and updates in international society recommendations. Prompt diagnosis and treatment can prevent the devastating consequences of this condition. Imaging modalities such as cardiac computed tomography and ¹⁸-fluorodeoxyglucose positron emission tomography/computed tomography are diagnostic tools that provide a complementary role to echocardiography in aiding diagnosis, pre-operative planning, and treatment decision-making process in these challenging cases. Understanding the strengths and limitations of these adjuvant imaging modalities is crucial for the implementation of appropriate imaging modalities in clinical practice.

Keywords: 18-fluorodeoxyglucose photon emission tomography/computed tomography; Cardiac computed tomography; Multimodality cardiac imaging; Prosthetic valve endocarditis; echocardiography.

Figure 1

Prosthetic valve endocarditis complicating prior bioprosthetic tricuspid valve replacement secondary to intravenous drug abuse relapse. Thirty-two year-old male with a history of intravenous drug abuse status post bioprosthetic tricuspid valve replacement presenting with methicillin-sensitive Staphylococcus Aureus prosthetic valve endocarditis due to relapsed drug abuse. Images from Panel A and B demonstrate a tricuspid valve prosthesis at mid esophageal 4 chamber right ventricular focused (A) and modified bicaval views (B) with severe thickening and attached vegetations on both sides of the valve. RA: Right atrium; RV: Right ventricle.

Figure 2

Prevalence of causative organisms according to timing and technique of valve intervention. The prevalence of causative organisms of prosthetic valve endocaridits in surgical left-sided valve replacement among 579 patients pooled from 5 studies[2,32-34,79] and transcatheter aortic valve replacement among 275 patients from 2 studies[35,36], categorized according to time since the index procedure. PVE: Prosthetic valve endocarditis; SVR: Surgical valve replacement; TAVR: transcatheter aortic valve replacement.

Figure 3

Para-valvular fistula in a patient with complicated endocarditis involving prior stentless aortic valve. Eighty-two year-old male with a history of coronary artery bypass grafts and stentless aortic valve replacement presenting with Streptococcus Gallolyticus prosthetic valve endocarditis complicated by aortic root abscess and fistulous tract treated with homograft aortic root replacement (25 mm Cryo-Life aortic allograft root), bovine pericardial closure of aortic root to right atrium fistula, right atrium reconstruction with bovine patch and bypass revision. A and B: TEE interrogating the aortic valve replacement with color compare demonstrated thickening of the leaflets and abnormal color flow into the right atrium; C and D: Additional imaging from deep transgastric views with color compare in the left ventricular outflow tract demonstrated a complex fistulous tract (Gerbode-type defect) communicating the left ventricular outflow track, right atrium and aortic root. RA: Right atrium; RV: Right ventricle; LVOT: Left ventricular outflow tract.

Figure 4

Transesophageal echocardiogram in a patient with mitral valve replacement endocarditis with 3D-reconstruction. Sixty-six year-old male with a history of coronary artery bypass graft and mitral valve replacement three years before presenting with Enterococcus Faecalis endocarditis. Transesophageal echocardiogram demonstrated severe structural degeneration of the mitral valve replacement with attached vegetation (A: Arrow). Color Doppler analysis demonstrated a large jet arising from the leaflet body consistent with prosthetic leaflet perforation confirmed by 3D-reconstruction (B-D).

Figure 5

Cardiac computed tomography in a patient with tricuspid valve replacement endocarditis with peri-valvular extension. Thirty-two year-old male with a history of intravenous drug abuse status post bioprosthetic tricuspid valve replacement presenting with methicillin-sensitive Staphylococcus Aureus due to relapsed drug abuse. Cardiac computed tomography demonstrated thickening of the valve leaflets (A: Arrow) and a 2.7 cm × 1.9 cm × 1.4 cm lobulated pocket of free-flowing blood/contrast interposed between the tricuspid annulus and the aortic annulus consistent with abscess/fistula (B: Arrow). Prominent pulmonary septic embolism was also detected (C: Arrow).

Figure 6

Transesophageal echocardiogram and cardiac computed tomography in a patient with metallic aortic valve replacement endocarditis, complicated by aortic dissection. Sixty-two year-old male with a history of type A aortic dissection status post repair with #27 CarboMedics valve conduit with reimplantation of the coronary arteries, #28 mm Hemashield bridge graft to the distal ascending aorta, presenting with PVE and extension of dissection from the distal ascending aorta to the femoral arteries. His transesophageal echocardiogram demonstrated the presence of a metallic AVR with pathological thickening of the aorto-mitral curtain and aortic root posteriorly (A and B: Star). Cardiac computed tomography axial view of the metallic aortic valve demonstrated widely open occluders and further inspection of the aorta at the level of the arch demonstrated the aortic dissection extending into the descending thoracic aorta (C and D: Arrow). RA: Right atrium; RV: Right ventricle; LA: Left atrium.

Figure 7

18-fluorodeoxyglucose photon emission tomography/computed tomography in a patient with prosthetic aortic valve endocarditis complicated by septic emboli. For details of clinical presentation, refer to Figure 6. Noted increased ¹⁸F-FDG-uptake along the aortic root graft (A-C: Blue arrow) and distant septic foci at the level of L3-L4 with extension of abnormal hypermetabolism into the left psoas muscle consistent with L3-L4 discitis and left psoas muscle abscess (A and D: Orange arrow).