The Pathology of Cardiac Interventions

Dr Stephen Preston

Royal Bournemouth Hospital

Dr Patrick J Gallagher

University of Southampton

Problems for the Pathologist

• As the number of interventions increase all pathologists will perform autopsies on patients with stents

• Finding and dissecting stents can be difficult

• Two questions: is the stent patent? If not is it thrombus or fibrous tissue?

• What is the appearance of the myocardial infarct?

No endothelium

Late DES failure

23 DES cases, died >30 days post procedure

14 (61%) had stent thrombosis (one died of stroke)

7 (30%) had patent stent(s)

4 cardiac deaths

2 (9%) had stent restenosis (both died of AMI/SCD)

3 non-cardiac deaths

Joner M et al, J Am Coll Cardiol 2006;48:193-202

Pathological factors in stent thrombosis

• Delayed endothelial coverage– Necessary for thrombosis, rare in bare metal stents– Maximum mean DES coverage 60-70%– More common with ruptured plaques

• Pro-thrombotic material– Thrombus– Penetration of necrotic plaque core– Hypersensitivity/inflammation?

• Abnormal flow– Malapposition– Restenosis

Limitations to the coroner’s autopsy

• Coroner’s duty:– Who died, when, where and how

• Purpose of autopsy in non-suspicious cases:– Provide a medical cause of death

• Finance– 112 coroners, £71million total budget

• 50% on autopsy, mortuary, toxicology etc

• Human tissue act• Training of pathologists

Solutions

• Improved training for registrars in histopathology

• UK Cardiac Pathology Network

• Chief coroner?

• Medical examiners?

References

• Carlsson J et al. Is late stent thrombosis a real clinical issue? A single-center experience and review of the literature. Clin Res Cardiol 2007;96:86-93.

• Finn AV et al. Vascular responses to drug eluting stents: importance of delayed healing. Arterioscler Thromb Vasc Biol 2007;27:1500-10.

• Finn AV et al. Does underlying plaque morphology play a role in vessel healing after drug-eluting stent implantation? J Am Coll Cardiol Img 2008;1:485-8.

• Joner M et al. Pathology of drug eluting stents in humans. Delayed healing and late thrombotic risk. J Am Coll Cardiol 2006;48:193-202.

• Luescher TF et al. Drug-eluting stent and coronary thrombosis: biological mechanisms and clinical implications. Circulation 2007;115:1051-8.