Guidewire coating debris found in nearly half of thrombus samples

Foreign material found in emboli and histological samples of cardiac tissue may be a sign that hydrophilic guidewire coating detaches more frequently than previously reported. The study published in the February issue of Circulation: Cardiovascular Interventions suggested that embolized guidewire coating may put patients at greater risk for complications.

Researchers from the Academic Medical Center in Amsterdam reviewed thrombus material collected between 2005 and 2009 and postmortem myocardial samples from 2009 through 2013. The 205 thrombus samples and 40 myocardial samples from patients with histories of PCIs were examined for foreign material. To compare the histological findings, they also took scrapings from the centers' most frequently used guidewire.

Maik J. Grundeken, MD, and colleagues noted the most frequently used guidewire in PCIs performed at the center was the Hi-torque (HT) Balance Middleweight Universal (Abbott Vascular), in about 70 percent of cases, followed by the HT Floppy (Abbott Vascular) in 7.8 percent, the HT Whisper (Abbott Vascular) in 3.4 percent, the HT Extra S’port (Abbott Vascular) in 1.5 percent and the Crosswire (Terumo) in 0.5 percent.

They found foreign material in 45 percent of the thrombus sections evaluated and in 10 percent of histology samples.

The guidewire used in 71 percent of the procedures where foreign material was found was the HT Whisper. The HT Balance Middle Weight Universal was used in 46 of those procedures with foreign material in the thrombus and in two of the histology samples where the guidewire used was known. The second most frequently used guidewire, HT Floppy, had the lowest number of cases where observed foreign matter was found (19 percent).  

Foreign material was also found in 47 percent of sections where the guidewire used was unable to be identified from records. No guidewire was identified in the PCIs for two of the other autopsies where foreign material was found; however, in the case of one patient, nine PCIs had been performed previously, the last of which had been 10 years prior to his death.

When they compared guidewire types, they found that those most likely to shed hydrophilic coating were either completely or partially polymer covered. Grundeken et al wrote that their findings suggested “the hydrophilic coating may adhere better if it is attached to the metal of the guidewire directly” as in the case of the HT Floppy, instead of adhered to a polymer cover, as is the case with the HT Whisper or HT Balance Middle Weight Universal.

Because patient risks from hydrophilic material aren’t clear, they suggested large clinical trials and registries with standardized data capture on wire types and foreign material findings. This could allow for better understanding of whether or not hydrophilic material places patients at greater risk for complications such as stent thrombosis or if, as was the case in one patient, foreign material may remain for years in the myocardium without much consequence.