The porcine valve type predicts obstructive thrombosis beyond the first three postoperative months in bioprostheses in the aortic position

Int J Cardiol. 2015 Nov 15;199:90-5. doi: 10.1016/j.ijcard.2015.07.022. Epub 2015 Jul 12.

Abstract

Background: Obstructive thrombosis of bioprosthetic valves is considered rare but may have dramatic consequences for the individual patient including repeat valve replacement, thrombolysis, or long-term anticoagulation. Whether the risk of obstructive thrombosis is dependent on the type of bioprosthesis (porcine versus bovine pericardial) is uncertain.

Methods and results: Between 2007 and 2012 a total of 1751 patients received a single stented bioprosthesis in the aortic valve position, 749 (43%) were porcine and 1002 (57%) bovine. During a mean follow-up of 3.4±1.9years, obstructive thrombosis (identified by an increase in mean pressure gradient≥20mm Hg or a decrease in velocity ratio≥0.05 and confirmed by either ECG-gated computer tomography, a return to baseline of stenosis parameters under treatment with a vitamin K antagonist, or histology in case of reoperation) was diagnosed in 17 patients with a porcine (2.3%) and none with a bovine valve (p<0.001). The cumulative probability of developing an obstructive thrombosis was significantly higher in patients with a porcine valve (p<0.001 log-rank test). Adjusting for differences in baseline variables and stratification by the estimated propensity score showed that strata with a high probability of receiving a bovine valve had the highest number of obstructive thrombosis in porcine valves. These findings were further confirmed in a Poisson model and a competing risk model including all-cause mortality. Treatment of obstructive thrombosis with a vitamin K antagonist was safe and effective in 15/17 patients.

Conclusion: The porcine valve type is an independent predictor of obstructive thrombosis in bioprostheses in the aortic position.

Keywords: Bioprosthesis; Obstructive thrombosis; Valvular heart disease.

MeSH terms

  • Aged
  • Animals
  • Aortic Valve / surgery*
  • Bioprosthesis / adverse effects*
  • Cattle
  • Echocardiography
  • Female
  • Follow-Up Studies
  • Germany / epidemiology
  • Heart Diseases / diagnosis
  • Heart Diseases / etiology*
  • Heart Valve Diseases / surgery
  • Heart Valve Prosthesis / adverse effects*
  • Humans
  • Male
  • Postoperative Complications / diagnosis
  • Postoperative Complications / epidemiology
  • Postoperative Complications / etiology*
  • Postoperative Period
  • Prognosis
  • Prosthesis Design
  • Retrospective Studies
  • Survival Rate / trends
  • Swine
  • Thrombosis / diagnosis*
  • Thrombosis / epidemiology
  • Thrombosis / etiology*
  • Time Factors