Acute hydrophilic-polymer nephropathy and acute renal failure

Fragments of hydrophilic polymer coating as an embolic material - rare complication and potential cause of death

The most common complications of percutaneous coronary interventions and other endovascular procedures include minor hemorrhage, hematoma, or infection at the insertion site [1]. Much more serious ones include damage to the vessel wall, dissection, shock from contrast administration, acute kidney injury, myocardial infarction [2] and ischemic stroke [3]. Ischemic complications can be caused by an embolic incident due to a thrombus formation or detachment of atherosclerotic plaque fragments [3]. A rarely diagnosed complication is ischemia caused by microembolisms from the material covering the equipment inserted into the vessel - hydrophilic polymer coating (HPC)[4]. We present an interesting case of HPC revealed in coronary vessels within myocardial preparations taken in forensic post-mortem examination conducted at the Department of Forensic Medicine in Bydgoszcz (L.dz. 676/19). This article raises the issue of clinical implications and forensic aspects.

Hydrophilic Polymer Embolism: Implications for Manufacturing, Regulation, and Postmarket Surveillance of Coated Intravascular Medical Devices

ABSTRACT

Hydrophilic polymers are ubiquitously applied as surface coatings on catheters and intravascular medical technologies. Recent clinical literature has heightened awareness on the complication of hydrophilic polymer embolism, the phenomenon wherein polymer coating layers separate from catheter and device surfaces, and may be affiliated with a range of unanticipated adverse reactions. Significant system barriers have limited and delayed reporting on this iatrogenic complication, the full effects of which remain underrecognized by healthcare providers and manufacturers of various branded devices. In 2015, the United States Food and Drug Administration acknowledged rising clinical concerns and stated that the agency would work with stakeholders to further evaluate gaps that exist in current national and international device standards for coated intravascular medical technologies. The present article reviews current knowledge on this complication as well as factors that played a role in delaying detection and dissemination of information and new knowledge once hazards and clinical risks were identified. Furthermore, organ-specific effects and adverse reaction patterns are summarized, along with implications for device manufacturing, safety assurance, and regulation. Qualitative and quantitative particulate testing are needed to optimize coated intravascular device technologies. Moreover, general enhanced processes for medical device surveillance are required for timely adverse event management and to ensure patient safety.

Ischemic Toe Ulceration Due to Foreign Body Embolus From Hydrophilic Polymer-Coated Intravascular Device

Hydrophilic polymer coatings are now widely applied to catheters and other intravascular devices used in neurovascular, cardiovascular, and peripheral vascular procedures. Emboli consisting of these materials have been previously identified in biopsies and autopsies following pulmonary infarction, stroke, gangrene, or death. We report a case involving a nonhealing foot ulcer that appeared following cardiac catheterization, stenting, and automatic implanted cardiac defibrillator (AICD) implantation in a patient without other evidence of significant peripheral artery disease. An 85-year-old woman with chronic atrial fibrillation, aortic valve stenosis, and coronary artery disease underwent coronary stenting and AICD implantation for ventricular tachycardia and syncope. She developed a toe ulcer shortly thereafter, which did not respond to standard treatment. A histological examination following amputation of the toe found amorphous basophilic material in capillaries adjacent to the edge of the ulcer, which was similar to material associated with hydrophilic polymer coatings. Ischemia and infarcts following endovascular procedures should not be presumed to result from thrombus or vascular disease, even if intravascular devices appear intact or properly placed after the procedure. To help establish the incidence of ischemia caused by hydrophilic polymer device coatings, if excision of ischemic or infarcted tissue after endovascular procedures using coated devices becomes necessary, the tissue should be evaluated microscopically. Surgeons should also consider the tolerance of distal organs to infarct or ischemia when selecting coated intravascular devices.

Cerebral Granulomatous Inflammation Secondary to Hydrophilic Polymer Embolization Following Thrombectomy

BACKGROUND Given the recent completion of multiple trials demonstrating the benefit of endovascular mechanical thrombectomy for select patients with proximal large artery occlusive ischemic strokes, there has been a large increase in the performance of these procedures. In the context of increased thrombectomy performance, there have also been increased reports of rare occurrences of granulomatous inflammatory response to the hydrophilic polymer which coat many of these interventional devices. CASE REPORT A 59-year-old female presented with a complete occlusion of her right proximal middle cerebral artery (MCA) and imaging showed a large area of penumbra. Cerebral angiogram and mechanical thrombectomy were successfully performed with reversal of clinical symptoms. Eight months following her stroke, she developed progressive recurrence of left-sided neurological deficits. After extensive workup culminating in tissue sampling, she was found to have developed granulomatous inflammation surrounding microscopic embolization of hydrophilic polymer, which is used to coat many interventional devices such as wires and catheters. The patient responded both clinically and radiographically to anti-inflammatory steroid therapy. CONCLUSIONS Recognizing the significant potential morbidity of a large vessel ischemic stroke and the expanded use of endovascular interventions aimed at staving off this disability, there are emerging and at times indolent complications from the use of hydrophilic polymer coated wires and catheters. This rare and potentially under-recognized complication should be considered in the differential for any patient with new neurological findings following cerebral intervention, especially given the consideration that this appears to a treatable complication.

Ultra-hydrophilic stent platforms promote early vascular healing and minimise late tissue response: a potential alternative to second-generation drug-eluting stents

AIMS

Simple surface modifications can enhance coronary stent performance. Ultra-hydrophilic surface (UHS) treatment of contemporary bare metal stents (BMS) was assessed in vivo to verify whether such stents can provide long-term efficacy comparable to second-generation drug-eluting stents (DES) while promoting healing comparably to BMS.

METHODS AND RESULTS

UHS-treated BMS, untreated BMS and corresponding DES were tested for three commercial platforms. A thirty-day and a 90-day porcine coronary model were used to characterise late tissue response. Three-day porcine coronary and seven-day rabbit iliac models were used for early healing assessment. In porcine coronary arteries, hydrophilic treatment reduced intimal hyperplasia relative to the BMS and corresponding DES platforms (1.5-fold to threefold reduction in 30-day angiographic and histological stenosis; p<0.04). Endothelialisation was similar on UHS-treated BMS and untreated BMS, both in swine and rabbit models, and lower on DES. Elevation in thrombotic indices was infrequent (never observed with UHS, rare with BMS, most often with DES), but, when present, correlated with reduced endothelialisation (p<0.01).

CONCLUSIONS

Ultra-hydrophilic surface treatment of contemporary stents conferred good healing while moderating neointimal and thrombotic responses. Such surfaces may offer safe alternatives to DES, particularly when rapid healing and short dual antiplatelet therapy (DAPT) are crucial.

Hydrophilic polymer vasculopathy with coinciding pseudoxanthoma elasticum-like changes in an amputated toe

For the past decades, hydrophilic polymer gel coating have been widely used on endovascular devices to decrease friction and to aid with binding and delivering of medications in drug-eluting stents. In the recent years, hydrophilic polymer emboli disease has been recognized as an iatrogenic adverse effect which has led to considerable morbidity and mortality of patients. This under-recognized embolic phenomenon now has reproducible pathognomonic histologic findings. Small- to medium-sized blood vessels are occluded with basophilic, amorphous, non-refractile, non-polarizable and whirled aggregates of foreign body material. Depending on the affected organ, the patients have variable symptomatology, from livedo racemosa, gangrene of extremities to cardiac arrhythmias, hemiparesis, stroke and death. Here, we present a unique case of hydrophilic polymer vasculopathy 6 years post-endovascular procedure with coinciding pseudoxanthoma elasticum-like changes. As the literature has seen increased reporting of individual cases and case series documenting the patients' diverse symptomatology; hydrophilic polymer vasculopathy should be entertained sooner in the patient's differential diagnosis.