New Pious Thoughts on Vascular Graft Infection

Jean Baptiste Morgagni, the father of pathology in 1761,1 provided in his seminal text, the encounter of a man with a likely syphilitic aneurysm “to think piously of his departure from this mortal life, which was very near at hand, and inevitable.” Further noting the presence of the patients mind, within seconds, the man would take his bedside basin and use it to capture his blood, as it rushed from his chest and soon after expired. While perhaps less dramatic in modernity, vascular graft infections, mycotic aneurysms, and endovascular infections remain an insidious source of patient morbidity and mortality. Infections of vascular grafts are associated with significant mortality and morbidity risk and cost an estimated $640 million annually in the United States.2 Indeed, as refinements in surgical and endovascular techniques have reduced risk, increasing the number of patients with significant co-morbid conditions, such as diabetes mellitus, that increase risk for infection. The accompanying AHA Scientific Statement3 includes a truly multidisciplinary working group of infectious disease specialists, surgeons, and interventionalists to address useful strategies for practitioners to tackle such difficult and serious medical entities. The Statement is divided into three domains, which have overlap with bacteriology, but remain distinct in presentation and management. Accordingly, it is useful to consider them separately.

Vascular Graft Infection

The authors provide a fundamental and clinically useful consideration of the location of the graft as central to the medical decision-making – is the graft extracavitary or intra-abdominal? Their staging system provided by Samson Classification is useful to consider options for treatment, but unfortunately has not been routinely applied in the medical literature. If this work motivates other to further adoption of the Samson system for reporting and analysis that would greatly serve our patients. Among the most complicated graft infections are those with intra-abdominal locations, and the authors derive a useful analysis of the state of the art, noting there remains no consensus on the procedure of choice.

Mycotic Aneurysms

Mycotic aneurysms are examined with the useful consideration that many may be underreported because patients can be asymptomatic. This commentator would further consider, even in septic patients, such mycotic aneurysms can escape diagnosis, thus further underestimating their true incidence. This section is further divided into the territories of intracranial, intracavitary (thorax and abdomen), and peripheral arteries. Herein, the necessary question of suitability of endovascular repair of these mycotic aneurysms is keenly considered. As the surgical expertise to reconstruct, bypass, or excise mycotic aneurysms requires significant expertise and hospital infrastructure to rescue the many complications that may ensue, the authors propose that endovascular therapy may be a useful bridge to later definitive therapy.

Endovascular Infections

The authors introduce the data regarding primary and secondary prophylaxis of vascular grafts and endovascular devices. Certainly, given the complexity of the infection problem in the vascular space, well appreciated by reading this Statement, “an ounce of infection is worth a pound of cure.” Given the frequency of stents and grafts placed daily, the common argument (and perhaps applicable standard) is to forego administration of antibiotics in the setting of bare metal stents. For stent-grafts, grafts, and prosthetics, I agree with the authors that antibiotics may be considered.

Summary

This AHA Scientific Statement, “Vascular Infections: Diagnosis, Medical and Surgical Management, Management of Complications, and Prevention” will be a useful reference for the modern physician who increasingly has to manage an aging, more medically complex, and often cumbersome outpatient evaluation in consideration of these diagnoses. From the historical perspective of Morgagni and Osler, both asserting how such infections humble the bedside physician, we will certainly cross paths with these infectious complications, but provided with the detail of this Statement, we will remain humble----but with a PLAN.