Coronary stent infections are an infrequent and life-threatening complication of percutaneous coronary interventions. Mortality in cases of coronary stent infections has been reported as high as 40–60% [1]. With less than fifty reported cases worldwide, there is a need for more data on this topic. A possible diagnosis must be suspected in patients with coronary stent placement in the preceding four weeks or access site complications presenting with fever without apparent localization, leucocytosis, or bacteraemia. Demonstrating an infected coronary artery stent complex by autopsy or surgery gives a definitive diagnosis of coronary stent infection. Table 1 depicts the diagnostic criteria for coronary stent infection proposed by Dieter [2].

Fever is the most common presentation. Stent infections may also present as recurrent stent thrombosis, acute myocardial infarction, and pericardial effusion [3]. In most cases, it occurs as an early presentation with onset between two days and four weeks [1]. However, very late presentations as long as five years post-stenting have been reported [4]. Staphylococcus aureus is the most common organism in 80% of cases, followed by Pseudomonas aeruginosa [1]. Risk factors for stent infection are the re-use of hardware like catheters, failure to maintain aseptic precautions during the procedure, local site infections and procedural complications like hematoma/ pseudo-aneurysms, repeated use of the same regional site for procedures, and prolonged placement of arterial sheaths [5]. Stent infections are more common with drug-eluting stents compared to bare metal stents. DES prevents the proliferation of neo-intima, and the uncovered stent struts serve as a nidus for bacterial infection [6].

First-line imaging modalities for diagnosis are echocardiography and coronary angiography. Echocardiography may sometimes pick up coronary aneurysms or collections surrounding infected stents. In our patient, TEE showed suspicion of an echogenic structure in the left AV groove, strengthening suspicion of stent infection. The presence of pericardial effusion may also be an indicator of stent infection. Cardiac CT, MRI, PET, and WBC scans may also help diagnose stent infections. A PET scan will show increased metabolic activity at the infected site, localizing the site of infection.

Mycotic coronary aneurysms and pseudoaneurysms, abscess formation, pericardial empyema, and purulent pericarditis are all dreaded complications [7]. Elison et al., 2012, reported a case of stent infection leading to abscess formation, which culminated in the death of the patient due to myocardial perforation and cardiac tamponade [8]. Coronary stent infections associated with infective endocarditis have also been reported [9]. Soman et al., 2015, reported a series of five cases of coronary stent infection caused by rapidly growing mycobacteria (RGM), which lead to infective endocarditis. Four out of five patients died due to complications of infective endocarditis, and the reuse of balloon angioplasty catheters was thought to be the plausible cause behind this complication [10]. Formation of coronary-cameral fistula secondary to coronary stent infection has also been reported [11].

Antibiotic therapy is the mainstay of treatment. Early-onset infections, arbitrarily defined as those with onset within ten days of stent placement, were likely to respond to antibiotic therapy alone [8]. Empirical antibiotic therapy should cover Staphylococcus aureus and Pseudomonas; prolonged antibiotic therapy lasting at least four weeks is recommended. However, foreign body infections may remain resistant to antibiotics until the source of infection has been removed from the body. Late-onset infections (with onset more than ten days after stent placement) and local complications require adequate antibiotic therapy along with surgical infected stent retrieval and aneurysm repair, removal of purulent pericardial fluid, granulomatous tissue, and revascularisation of the affected coronary vessel by CABG.