INTRODUCTION:
Adhesions are fibrotic connections resulting from tissue trauma and
subsequent inflammation and ischemia during surgery. While adhesions are
germane to many forms of surgery, postoperative pericardial adhesions
(PPAs) are an important clinical problem in cardiac surgery. The
resulting obliteration of tissue planes puts vital structures at risk
for injury during re-operation and sternal re-entry, particularly the
aorta, right ventricle, and right atrium. At least 10% of cardiac
surgeries require re-operation.1 The incidence of
re-entry injuries in these procedures is relatively low at approximately
3%; however, they are associated with almost three times greater
mortality rates.2 PPAs hinder dissection and
visibility too, thereby increasing operative time, cardiopulmonary
bypass time, and blood loss. The increased morbidity, mortality, and
economic costs posed by PPAs during re-operation ultimately place the
patient at risk and pose an undue burden on the surgical team.
In an effort to improve outcomes, barriers have been developed to limit
adhesion formation. These adhesion barriers have now been used in
cardiac surgery for over four decades and can be divided into two
categories: nonresorbable and bioresorbable.3Nonresorbable barriers include both prosthetic and/or xenograft
materials while bioresorbable barriers include pharmacologic agents
and/or resorbable membranes.3, 4 Nonresorbable
barriers create indefinite physical separation between tissue planes and
provide a readily discernable area at re-operation. Nonresorbable
barriers were the first type of products developed to prevent PPAs.
However, bioresorbable barriers have recently been developed more and
have garnered interest among both patients and surgeons. Bioresorbable
barriers confer a potential relative benefit by not leaving a foreign
body in place for long periods of time and not requiring re-operation
for barrier removal. The only licensed adjuncts for PPA prevention at
this point in time are either nonresorbable or bioresorbable physical
barriers.5 Pharmacotherapy agents that act at the
molecular level have yet to be identified. Although numerous products
currently exist, a perfect solution to PPAs has yet to be identified.
Research efforts analyzing adhesion barriers have historically focused
on abdominal and gynecologic surgery.6, 7, 8, 9Limited data currently exists with respect to cardiac surgery. Recent
systematic review have assessed adhesion and particularly PPA formation
and prevention methods.3, 5 However, none have
compared the efficacy and safety of specific adhesion barriers for
preventing PPAs in the clinical setting. The study presented here
addresses this knowledge gap by providing the first major systematic
review of adhesion barriers in cardiac surgery.