Postrevascularization Management in the ICU
Hospitalists often are charged with caring for cardiac patients who have undergone a revascularization procedure and have not been cleared for discharge. These patients may experience cardiac-related symptoms or complications from surgery that need to be assessed, and hospitalists may benefit from deeper understanding of how to evaluate and manage these patients in the context of their presurgical history. Given the risk of cardiac disease progression following cardiac surgery, it is important to recognize when nuclear imaging is safe and appropriate after revascularization surgery.
Possible complications following myocardial revascularization include renal failure or dysfunction, sternal infection, neurological complications, or gastrointestinal complications (which are rare, <1%).1 Each of these possible postrevascularization complications have associated presurgical clinical predictors and surgical factors that might give some indication of what to expect in the postoperative period for patients undergoing revascularization, either coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI).
Depending on the definition and patient group, acute renal failure is observed in 1% to 5% of patients undergoing cardiac surgery.1 For patients undergoing CABG, preoperative risk factors for postoperative renal dysfunction are advanced age, a history of moderate to severe congestive heart failure (CHF), prior CABG, type 1 diabetes mellitus, and pre-existing renal disease.2 Regarding sternal infection after CABG, studies have consistently associated this complication with obesity and reoperation, while the association of postoperative complications with other risk factors, such as the use of both internal mammary arteries, duration and complexity of operation, and the presence of diabetes, have been reported inconsistently.2 Predictors of neurological complications (type 1 deficits associated with major, focal neurological deficits, stupor, and coma; type 2 deficits characterized by deterioration in intellectual function or memory) include age (>70) and a history of significant hypertension.2 Though rare, there is a risk of gastrointestinal complications, such as peptic ulcer disease, pancreatitis, cholecystitis, gut ischemia, ileus, and hepative dysfunction, following cardiac surgery.1 Lastly, it is important to note that studies have shown that there is no apparent benefit of revascularization over medical therapy in the absence of myocardial viability,3 which may be assessed preoperatively using noninvasive tests, such as single photon emission computed tomography (SPECT), positron emission tomography (PET), or cardiac magnetic resonance imaging (MRI).
PREOPERATIVE ASSESSMENT FOR ANESTHESIOLOGY
Specific patient factors and the type of surgery are of critical importance to the anesthesiology staff. Pre-anesthesia evaluation prior to cardiac surgery consists of the consideration of information from multiple sources that may include the patient’s medical records, interview, physical examination, and findings from medical tests and evaluations.4
The amount of time patients spend in the ICU after cardiac surgery is usually a short period of recovery prior to discharge. In a small percentage of cases, treatable complications could require additional time and resources on the part of the hospital and ICU.1 The main components of care in the ICU following cardiac surgery include monitoring, respiration and airway management, fluid and electrolyte management, management of hypo- and hypertension, and low cardiac output.1 Complications outlined in the above section on preoperative assessment must be remedied according to clinical judgment prior to discharge; understanding the possible postsurgical complications prior to surgery is imperative. Patients who survive cardiac surgery are still at risk for disease progression; therefore, medical care in the form of anti-platelet therapy, beta-blockers, ACE inhibitors, and statins might be appropriate.1
IMAGING AFTER REVASCULARIZATION
Some typical symptoms of new cardiac disease include angina (most common), dyspnea, or irregular heartbeat. Because a patient may have an asymptomatic worsening of cardiac disease following revascularization, nuclear imaging might prove to be a useful tool in assessing the extent of postsurgical disease progression.5 According to published guidelines, neither exercise testing nor radionuclide imaging is indicated in the two months after PCI without a specific indication; the major indication for imaging in patients after successful PCI is to evaluate symptoms suggesting new disease.5 In patients who have undergone CABG, atypical chest pain is common early in the postoperative period and is usually nonischemic in origin. Perfusion imaging might be helpful in assessing residual ischemia in the presence of an abnormal electrocardiogram (ECG) or symptoms suggesting ischemia.5
In the postoperative setting of cardiac surgery, the role of intensive care specialist is integral, but the team of clinicians working with the patient, including the hospitalist, might be involved as well. Most notably, hospitalists play an important role in patient recovery postsurgery, and discharging patients to the community or to an appropriate rehabilitation facility. Close collaborations between surgeons, anesthesiologists, and the intensive-care team have brought about advances in anesthetic techniques, cardiopulmonary bypass technology, and methods of myocardial protection.2 In this context, the broad point of view of the hospitalist with regard to the care of individual patients might allow for an evolution in hospital protocol for future cardiac surgery patients.
Matthew Landler, MD, from the Northwestern University Feinberg School of Medicine, is the consultant for The Heart and Hospital Medicine series. Dr. Landler is a consultant for Astellas Pharma US, Inc.