Stroke Risk in Cardiac Surgery: New Guidance for Averting a Dreaded Complication

The first comprehensive collection of preventive measures has been assembled for one of the most dreaded complications of cardiothoracic surgery — perioperative stroke. The guidance comes in the form of a new American Heart Association (AHA) scientific statement developed by a multidisciplinary panel of experts and published online in Circulation.

“The main message is that in perioperative care you want to avoid stroke and act on it quickly if it happens,” says Cleveland Clinic cardiothoracic surgeon Faisal Bakaeen, MD, who served on the writing group for the statement.

No silver bullet for a feared complication

Perioperative mortality can be as high as 20% in patients who develop stroke during cardiothoracic surgery. Morbidity from stroke is also greatly feared: In a recent survey, 81% of patients said freedom from stroke was more important than length of life, hospital readmission or freedom from life in a nursing home.

In response to these challenges, the AHA convened the expert panel to review the literature and provide recommendations for reducing perioperative stroke risk in adults undergoing cardiac and proximal thoracic aorta procedures; the guidance doesn’t apply to carotid or other vascular operations, the authors note.

The document emphasizes the multiple contributors to stroke risk in this setting and the need for multifaceted strategies to mitigate the risk and consequences of stroke. “The pathogenesis of perioperative stroke is multifactorial,” notes Dr. Bakaeen, “but having information on its mechanisms, diagnosis and treatment can help minimize the risk of stroke for an individual patient and improve the outcome if a stroke should occur.”

Scope of the statement

A key area addressed by the statement is identification of high-risk patients and methods of assessing risk. “The preoperative workup should include assessment of the aorta with CT, taking a history of cerebrovascular disease and doing a physical exam for possible neurologic symptoms,” says Dr. Bakaeen.

Discussion is then devoted to considerations in intraoperative management to prevent stroke, including (among others):

• The value of intraoperative neuromonitoring during aortic surgery
• Assessment of the ascending aorta with epiaortic ultrasound in high-risk cases to optimize cannula and clamp placement
• The no-touch, off-pump technique
• Use of various tools to minimize manipulation of a diseased aorta
• Intraoperative blood pressure management
• Left atrial appendage closure and ablation to reduce atrial fibrillation
• Blood transfusion strategies

A final section addresses diagnosis and treatment of perioperative stroke, including clinical and radiographic evaluation and strategies for medical, endovascular and surgical management.

The document concludes with a figure outlining 19 suggested actions for lowering stroke risk, from intraoperative measures to measures for early stroke diagnosis, treatment of perioperative stroke and prevention of postoperative stroke.

“With mortality outcomes for cardiac and cardio-aortic surgery continuing to improve, it is increasingly important that we expand focus from not only extending lives but to optimizing our patients’ quality of life,” observes Eric Roselli, MD, Chief of Adult Cardiac Surgery at Cleveland Clinic. “The authors of this statement provide practical recommendations based on literature review to minimize risk and improve rescue from intraoperative and perioperative stroke.”

Multidisciplinary expertise is essential

Despite best efforts, strokes occur. A new Cleveland Clinic review of perioperative stroke risk in coronary artery bypass grafting (CABG) notes that about 60% of intraoperative strokes in this setting result from thromboembolism and about 40% from cerebral hypoperfusion.

Because intraoperative strokes become apparent when patients awaken from anesthesia, it is critical that a multidisciplinary team be available for immediate action, if required. For this reason, the AHA statement’s writing panel comprised representatives of just such a team — neurologists, vascular neurologists, neurosurgeons and specialists in cardiac anesthesiology/critical care medicine — in addition to cardiac surgeons with a specific interest in outcomes, quality and stroke prevention.

“We emphasize collaboration with critical care and anesthesiology to aggressively monitor patients,” says Dr. Bakaeen. “Early extubation for neurological assessment for potential stroke may be required. We also want to detect hypertension or anemia and act quickly to correct it, if any neurological deficit is detected.”

Cleveland Clinic has an emergency response team that’s called to the bedside on suspicion of stroke to order tests and perform any necessary intervention. “If a large vessel is obstructed, mechanical thrombectomy may be undertaken since clot removal can reverse or mitigate the neurological deficit,” Dr. Bakaeen explains. “Systemic thrombolytic therapy is generally contraindicated in postoperative patients, due to increased risk of bleeding.”

The Cleveland Clinic experience

While the methods detailed in the AHA statement are not guidelines since many of the recommendations are based on sparse evidence or expert opinion, Dr. Bakaeen speaks from experience when he says they are effective.

“At Cleveland Clinic we have seen a dramatic reduction in stroke incidence after heart surgery — especially valve and aorta surgery — due to preoperative imaging of the aorta and aggressive patient management in the operating room,” he says.

“Widespread use of monitoring, corrective intraoperative strategies and selective use of adjuncts such as circulatory arrest, hypothermia and selective brain perfusion have helped us reduce stroke in aorta surgery,” Dr. Bakaeen continues. “We’ve also minimized pump time and ischemia, which has reduced stroke and damage to other organs from all cardiac procedures, including CABG and valve.”

He adds that optimal care requires a multidisciplinary approach: “The team strategy starts before surgery, is an active part of surgical planning and execution, and continues postoperatively in the ICU and stepdown unit.”

Further progress in store

Dr. Roselli notes that there’s good reason to expect progress against perioperative stroke to continue apace. “As imaging quality and data analysis improve with advances in computer technology, we will progress from making decisions based on average treatment effect towards individualized precision medicine,” he says. “This will allow us to understand which techniques are best tailored to each patient around the time of cardiac surgery to further reduce strokes from complicating these life-saving operations.”