Is a fully heparin-bonded cardiopulmonary bypass circuit superior to a standard cardiopulmonary bypass circuit?

Abstract

A best-evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Is a fully heparin bonded cardiopulmonary bypass circuit superior to a standard cardiopulmonary bypass circuit?' Altogether more than 792 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated (Table 1). The studies analysed show that perfusion with heparin-coated and heparin-polymer-coated bypass does not increase the risk of adverse effects but reduces blood loss, re-operation rates, ventilation time, length of intensive care unit (ICU) and hospital stay and is also associated with improved biocompatibility, as evidenced by platelet preservation, reduced leucocyte and complement activation, and proinflammatory cytokine production. The various coated circuits have comparable biocompatibility as evaluated by a range of inflammatory markers and clinical outcomes. Three studies documented a significant decrease in post-operative blood loss (P = 0.001-0.54) and a meta-analysis found that perfusion with a heparin-bonded circuit resulted in a reduction in blood transfusion requirements (20%), ventilation time (P < 0.01), length of time in the ICU (P < 0.01) and also hospital stay (P = 0.02). Two studies found reduced levels of polymorphonuclear elastase (P < 0.018-0.001) and two trials concluded that the use of heparin-coated circuits in combination with low-dose systemic heparin (activated clotting time >250) resulted in the greatest clinical benefit and improvement in inflammation. One study documented significant platelet preservation with the use of third-generation heparin-polymer-bonded circuits (P ≤ 0.05). We conclude that despite heparin-bonded and newer third-generation heparin-polymer-bonded cardiopulmonary bypass circuits having a greater cost per person, their improved clinical outcomes and biocompatibility in patients undergoing cardiac surgery make them a preferable option to standard non-heparin-bonded circuits.

Variability in Anticoagulation Management of Patients on Extracorporeal Membrane Oxygenation

“…Several studies have investigated the impact of these heparin-bonded circuits on the inflammatory response, platelet preservation, fibrinolysis, blood loss and amount of blood transfusion required, during ECMO and cardiopulmonary by-pass, with evidence suggesting reduced platelet activation, decreased leukocyte and complement activation and lower pro-inflammatory cytokine production, as well as decreased blood transfusion requirements. (27–30) It is not clear, though, how these findings translate for prolonged ECMO runs and in patients of different ages, co-morbidities and indications for ECMO. In this survey, the use of heparin-bonded circuits was reported by 61% of respondents, either as tip-to-tip or for certain components.…”

ECMO Biocompatibility: Surface Coatings, Anticoagulation, and Coagulation Monitoring

“…With respect to inflammation, most studies demonstrate reduced inflammatory response, particularly in the interleukins, alternative complement pathway and polymorphonuclear cells, compared to controls and other coating systems [12,[20][21][22][23][24][25]26]. Meta-analyses of the benefits of heparin coating have consistently found improvements in transfusion requirements, arrhythmias, ventilator times, and lengths of stay in the hospital or ICUs when using heparin-coated circuits for cardiopulmonary bypass [17,27,28,29]. One important aspect of many of these studies has been that many have focused on short-term impacts of heparin coatings.…”

Inflammatory response and extracorporeal circulation

“…[56]), were tested with respect to their inflammatory properties. Until now, only few strategies were able to significantly ameliorate the inflammatory response and to improve patients' outcome.…”

“…Several attempts have been made to improve the biocompatibility of circuit compounds by coating the circuit surfaces with heparin, poly-2-methoxyethylenacrylate, hyaluronan or phosphophorycholine [16]. A recent meta-analysis by Mahmood and colleagues provides evidence that heparin coating does not increase the number of adverse events, but it decreases blood transfusion requirements, re-operation rates, time of mechanical ventilation and length of stay (LOS) in the intensive care unit (ICU) and in hospital [56]. The authors justify the usage of coated CPB circuits with improved clinical outcome.…”