Cardiovascular complications and management after adult cardiac surgery

Abstract

Over the last several decades, the risk profile and severity index of patients undergoing cardiac surgery have increased as cardiac surgery has become more sophisticated. Cardiac surgical patients in the twenty-first century are older, have greater disease burden, and possess diminished physiologic reserve, including decreased ventricular function. Many of these patients have already undergone prior cardiac interventions and need additional, more complex surgical procedures. Consequently, these patients are at risk for developing major postoperative complications. Recognition and management of these complications are paramount to the cardiac anesthesiologist and intensivist. Preoperatively, cardiac centers worldwide are developing risk calculators to stratify cardiac surgery patients. Large databases (i.e., Society of Thoracic Surgeons) and the use of risk tools (i.e., EuroSCORE, STS score) have focused on predicting complications post-cardiac surgery. The EuroSCORE model (standard and logistic) has been used to predict in-hospital mortality, 3-month mortality, prolonged length of stay (≫12 days), and major postoperative complications (intraoperative stroke, stroke over 24 h, postoperative myocardial infarction, deep sternal wound infection, re-exploration for bleeding, sepsis and/or endocarditis, gastrointestinal complications, postoperative renal failure, and respiratory failure). Recognition of complications postoperatively is done through continuous invasive and noninvasive monitoring. This is accomplished via continuous electrocardiogram (ECG), arterial blood pressure measurement via arterial catheter, frequent arterial blood gas sampling, central venous pressure (CVP) measurement via central venous catheter, pulse oximetry, and evaluation of chest tube drainage. Additionally, the use of a pulmonary artery (PA) catheter and mixed venous oxygen saturation may be indicated. Chest X-rays are used to assess pleural effusions; transthoracic and transesophageal echocardiography can diagnose cardiac tamponade, illuminate postoperative structural abnormalities, and assess right and left ventricular function postoperatively. The main insult usually sustained by the patient requiring cardiac surgery is related to inadequate myocardial contraction accompanied by low cardiac output with potentially compromised central and peripheral systemic indices. Poor diastolic function is linked to the inability to wean from cardiopulmonary bypass. Patients who cannot be weaned from CPB may require alternative means of extracorporeal support after separation from CPB. Innovative techniques for circulatory support devices have been developed, and newer more advanced and portable devices continue to enter the mainstay of modern- day cardiac practice. Initially, intra-aortic balloon pumps (IABPs) and centrifugal pumps were developed, whereas now rapidly evolving technical changes have led to new and improved pneumatic and electrically driven internal assist devices that are smaller and provide a less invasive means of insertion. These devices are being increasingly utilized in an effort to provide supportive assistance to one or both ventricle with increased safety and durability. Additionally, for patients who sustain permanent myocardial damage during cardiac surgery or with end-stage heart disease, multiple devices for extracorporeal support may be utilized as bridges to transplantation or as destination therapy. Despite the utmost diligence and care in managing the patient undergoing cardiac surgery, multiple complications may ensue in the immediate postoperative period. This chapter will discuss the major complications that can arise and various treatment measures that may be employed by the cardiac anesthesiologist, cardiac surgeon, and critical care intensivist.