Introduction
Heart valve surgery is used for the repairing or replacement of valves of the heart that are diseased. The patients receive general anesthesia in this type of surgery whereby the surgeon makes a large surgical incision in the breastbone. The incision is meant to enable the surgeon to reach the aorta and the heart (Kato Paragraph 2). The relevance of stroke to the procedure of open-chest valve surgery is that it is one of the risks associated with cardiac surgery. Other risks include death, failure of the kidneys, cardiac arrest, irregular beats of the heart, and post-pericardiotomy syndrome (Kato Paragraph 10). This essay, therefore, provides a literature review of the prevalence of stroke and the causative factors in open-chest valve surgery.
Background Information
Diseases of the heart valves are becoming a concern for public health because of the increase in life expectancy and the discovery of new modalities of treatment. Literature describing the experiences of patients following heart surgery are limited even though the procedure presents the patient with a lot of challenges (Berg et al. 1). As the heart valve illness progresses, the clients experience signs such as dyspnea, easily getting tired, and irregular rhythms of the heart. A heart valve surgery becomes inevitable when the illness cannot allow the individual to get involved in basic chores of activities of daily living.
The replacement of the valves of the heart through open surgery was until recently the only treatment that proved efficacy as explained by Berg et al. (1). The procedure, however, results in more complications in the patients who are elderly as opposed to the younger clients making it not always suitable for the elderly patients. With such, alternative options such as the Transcatheter Aortic Valve Implantation have been developed for the management of the clients whose ages are advanced. Such new developments are meant to facilitate quicker recovery, success during surgery, and desired clinical results (Berg et al. 1). However, the post-surgical quality of life of the concerned patients is affected regardless of the surgical approach adapted to manage the patient’s heart condition.
The patients who are more fragile also bear the risk of acquiring depression, post-traumatic stress disorder, as well as anxiety. On the other hand, the invention of valve surgery that is minimally invasive is viewed as a solution for the adverse effects associated with invasive surgical procedures. For example, Lucà et al. (1) explained that minimally invasive mitral valve surgery has proven efficacy as an option for the conventional open heart surgery. The approach is said to result in low morbidity after surgery and prevents short-term mortality. Consequently, most medical practitioners are increasingly implementing minimally invasive techniques for the routine management of valve conditions. Reports suggest that both the long and short term results are good (Lucà et al. 2).
Of primary concern to medical practitioners is the occurrence of neurological events that include stroke after the surgical management of valve problems. As explained by Lucà et al. (6-7), the patients experienced episodes of confusion and low oxygen concentrations in the body after the clients underwent invasive corrective procedures. On the other hand, it was established that the adverse effects were lower even though there was no significant difference in the patients’ pattern of experience with stroke when less invasive approaches were employed. The literature reports that the benefits of minimally invasive techniques include decreased pain after the procedure, improve respiratory function, reduces surgical trauma, and significant satisfaction rates by the patients (Lucà et al. 9).
According to Costa et al. (para. 3) stroke is one of the leading causes of death, permanent damage to the neurological functions, and increased spending on health care in the United States of America. Additionally, 18% of deaths that result from causes related to cardiovascular pathophysiology comes about as a consequence of the development of a stroke that is also referred to as a cerebrovascular accident. When considering heart surgery, ischemic stroke is one of the most common complications that is most feared that follows most operation procedures. Ischemic stroke following cardiac surgery occurs in approximately 2% of all the patients that undergo cardiac surgeries in the United States of America.
Additionally, up to 6% of the patients that undergo Coronary Artery Bypass Surgery (CABG) may experience an ischemic stroke as a complication following the procedure. The risk, however, rises to an incidence of 12% in patients that undergo surgical therapy following severe carotid stenosis (Costa et al. para. 3). Additionally, the risks that have been identified to play a role in the development of stroke after heart surgery include age greater than 70 years, being female, and having hypertension. Other risk factors include diabetes mellitus, failure of the functions of the kidneys, smoking, and chronic obstructive pulmonary disease.
Also, diseases of the peripheral arteries, an ejection fraction of 40%, a positive history of ischemic stroke as well as transient ischemic attack, carotid stenosis, calcification of the aorta, and an extended cardiopulmonary bypass time are other risk factors (Costa et al. para. 3). In a study of 430 patients over the period from January 2007 to July 2010, Cao et al. (157) also identified different predisposing factor for the development of stroke after the procedure of Coronary Artery Bypass Grafting. The study by Cao et al. indicated that 7.4% of the total number of study subjects experienced a stroke after getting operated on. The study established the existence of risk factors such as pre-surgical left ventricular ejection fractions less than 50%, on-pump surgery, low blood pressure, and atrial fibrillation occurring after surgery.
Further, unstable angina, cardiac infarction, a left ventricular ejection fractions less than 50%, and low blood pressure was established as risk factors that were independent for the occurrence of a stroke following heart surgery. Further, apart from coronary artery bypass grafting acting as a significant causative risk factor, it was found to account for higher hospital deaths, longer stays in hospital, and increased spending regarding support for rehabilitation and hospital management (Cao et al. 157).
The Prevalence of Stroke in Open Chest Valve Surgery
Stroke continues to represent what can get termed as the “Achilles heel” of cardiac surgery. Neurologic events that are peri-procedural in nature remain prevalent, and stroke are reported in 2% to 5% of the patients that undergo cardiac surgical procedures. In octogenarian clients, the prevalence increases to at least 12.8% (Messe et al. 2254). Because patients suffering from cardiac illnesses fear stroke as well as other adverse complications of the neurologic system, they hesitate to undergo successful procedures that could save their lives. Such hesitations ultimately add to the statistics of deaths due to unattended heart problems. The advent of the aortic valves that are sutureless is termed as one way of making the procedure of minimally invasive aortic valve replacement easier and quicker.
The ease is achieved through the use of procedures that are less invasive and therefore reducing the risk of stroke (Casselman Part IV). According to the study conducted by Whitlock et al. (906) in Canada, the strongest factors associated with the development of stroke after surgery were advanced age (more than 65 years), a positive history of heart attack or transient ischemic attack, and peripheral vascular disease. Additionally, the study established that a combination of valve surgery and coronary bypass grafting predisposed the patient to stroke more than valve surgery subjected the patients to acquiring stroke. Of the 108,711 study subjects used as respondents for the study by Whitlock et al. (908), 1. 8% of the subjects reported that they experience a stroke before being operated on while 3.6% of the study subjects were found to have had a heart attack within the following two years after undergoing heart surgery.
It further got established that patients who underwent cardiac surgery were the ones with the most predisposition for getting a stroke within the early days of receiving cardiac surgery (Whitlock et al. 909). Such patients also had a continued chance of experiencing stroke over the following two years of surgery. Additionally, the study determined that new-onset postoperative atrial fibrillation served as a predictor for the acquisition of early stroke by such clients. According to Carnicelli (Paragraph 9), the replacement of a valve with a bioprosthetic device resulted in thromboembolic strokes that ranged from 0.2% to 3.3% every year in the United States of America, with the risk being higher in valves in the mitral position when comparisons were made with the valve in the aortic position.
Carnicelli (para. 10) further reported that the rates of strokes were even lower for patients that underwent valve replacement but experienced a normal sinus rhythm ranging from 0.2% to 0.7% every year. Messe et al. (2255) on the other hand stated that some reasons exist to lead to the belief that the risk of a stroke resulting from aortic valve replacement is higher than what is reported in the literature. Additionally, the research by Messe et al. (2257) that was conducted between April 2008 and September 2012 recruited 721 study subjects. Among these study subjects, it was established that clinical strokes post-surgery occurred in 17% that represented 34 of the patients. 2% of the recruited study subjects were determined to experience transient ischemic attacks, while complications from stroke resulted in the death of 5% of the patients. The study also proved that the least common form of clinical stroke was ischemic and occurred in only two of the study subjects who were later found to have intracerebral hemorrhage after neuroimaging tests were conducted.
Also, the risk of a patient suffering from a stroke after Aortic Valve Replacement in the general population was determined to be approximately 1.5% according to the findings by Daneault et al. (2143-2150). The risk of developing the stroke was also established to increase by approximately between 2% and 4a% in individuals who are older and of higher risk. Furthermore, patients treated with Transcatheter Aortic Valve Replacement experienced various forms of strokes in the range of 1.5% to 6%. In the only randomized trial comparing surgical Aortic Valve Replacement and Transcatheter Aortic Valve Replacement by Daneault et al. it was found out that a higher risk of acquiring stroke after thirty days of heart surgery existed in the general population of patients that went through the surgical procedures.
The strokes ranged from minor and major strokes to transient ischemic attacks. Neragi-Miandoab and Michler (4) stated one of the most troublesome complications is stroke following a Trans-catheter Aortic Valve Implantation (TAVI). Stroke frequently occurs during the procedure or a short while after with the frequency increasing as a result of repeated attempts to conduct an implantation of a valve prosthesis. Neragi-Miandoab and Michler (5) also explained that the Transcatheter aortic valve results in pronounced emboli in the cerebrum which also determines how severe the stroke might get following the surgical procedure. In addition to the other risk factors mentioned before, Neragi-Miandoab and Michler (6-7) a body mass index of more than 20kg/m2, a positive history of stroke and atrial fibrillation heightened the chances of a stroke occurring after a patient underwent open heart valve surgery.
In relation to the above risks, the study by Boeken et al. (para. 3) in Canada found out that a total of 2.1% of the total number of patients that underwent any surgical procedures of the heart experienced a stroke. Out of all the patients that experienced a stroke, 2.9% had undergone a procedure to correct a valve problem while 1.9% had undergone a carotid artery bypass grafting.
The Causative Factors of Stroke in Open-Chest Valve Surgery
One of the causes of stroke post valve surgery is a calcified ascending aorta that results in difficulties in cardiac surgery. Recently, the proportion of high-risk individuals that include the elderly undergoing cardiac surgery has increased in number, representing a significant health problem Messe et al. (2258). The presence of severe calcification of the aorta predisposes the patient to the development of postoperative emboli that subsequently cause stroke and other serious neurological consequences. On the other hand, the literature reveals that preoperative dysfunction of the kidneys, dialysis, and stenosis of the aorta are responsible for the occurrence of severe aortic calcification.
Mostafa et al. (65) explained that atrial fibrillation that occurs in 5% to 40% of patients after undergoing the procedure of coronary artery bypass graft surgery also predisposes them to stroke. Additionally, the arterial fibrillation is responsible for post-surgical mortality and morbidity. Mostafa et al. (65) also reported that atrial fibrillation occurred during the early days following coronary artery bypass graft and in 37% to 50% after valve surgery. The role played by atrial fibrillation to result in stroke after valve surgery is that it worsens the hemodynamic status of the patient and heightens the chances of the formation of emboli that may ultimately cause a cerebrovascular accident. Studies by Mostafa e al. (65) also indicated that 2% of patients who have undergone coronary artery bypass graft surgery experience stroke as a complication, having suffered from atrial fibrillation earlier. Longer hospital stays and mortalities, poor life quality, and other adverse effects precede the development of atrial fibrillation. Mostafa et al. (66) also explained that some preoperative risk factors are responsible for the occurrence of stroke following open heart valve surgery. These factors include advanced age, being genetically predisposed, the female gender, as well as chronic renal illness.
A positive history of congestive cardiac failure, chronic obstructive pulmonary disease, diabetes mellitus, rheumatic heart disease, previous heart surgery and obesity also get implicated in the occurrence of post valve surgery. Furthermore, the absence or stoppage of medical treatment, severe proximal stenosis of the right coronary artery, diseases of the mitral valve, and an increase in the size of that left atrium also play a role in the development of cerebrovascular accident in a patient who has undergone open-chest valve surgery (67). Intraoperatively, the factors that may cause the development of stroke after a valve operation include prolonged mechanical ventilation, lack of enough oxygen supply to the atria, and low potassium and magnesium levels (68).
The Prevention of Stroke after Heart Surgery
According to Costa et al. (para. 6), various approaches have been applied to help in the reduction of stroke postoperatively. Such procedures include avoiding of high body weight, treating arrhythmias early, the prevention of manipulation and cannulation of the aorta, and maintaining sufficient supply of oxygen to the brain. Furthermore, the use of membrane oxygenators and arterial filters, avoiding hyperglycemia, the use of stents or carotid endarterectomy for the management of severe carotid stenosis have been found to be effective even though still debatable in the available literature as postulated by Costa et al. (para. 6). Abah and Large (155-157) explained that scanning for the identification of aortic atheroma is effective in the prevention of the development of a stroke after surgery.
Abah and Large stated that studies had demonstrated a reduction from 3.3% to 1.1% of post-operative strokes following the application of intra-operative epi-aortic scanning in the United Kingdom. Additionally, Abah and Large (155-157) explained that the guidelines developed by American Society of Echocardiography and the American Society of Anesthesiologists recommended the application of epi-aortic scanning in all individuals that possess characteristics suggestive of an increased risk for the development of stroke due to emboli. Such patients include those with advanced age, the female gender, vascular or cerebrovascular illnesses, and a blood pressure that is high. Also, some literature postulates that the adoption of minimally invasive cardiothoracic surgery has the prospect of preventing a stroke from occurring as a complication of surgery Whitlock et al. (909).
Patient experiences.
The study conducted by Berg et al. (1) revealed that patients were most concerned about regaining physical strength and resuming normality after cardiac valve surgery. Themes such as altered social networks, relatives that were supportive, repeated visits to the hospitals, and rehabilitation emerged in the interviews conducted on the daily activities of post-surgical patients. Additionally, patients were concerned about the complications of surgical procedures such as stroke, bodily attention, feelings of sadness, and uncertainty with the process of recovery (1). Additionally, after getting released from the hospital, such patients needed guidance for proper interpretation of symptoms of their respective heart conditions as well as the recognition of surgical complications. Such experiences are common after any surgical approaches to the management of heart conditions.
Conclusion
Previously, heart surgeries were impossible but with the occurrence of significant advances in the surgical field, it is now possible to surgically correct cardiac pathology following surgical approaches. The invention of the cardiopulmonary bypass machines has made it possible for the performance of modern day cardiac surgery. However, even with the inventions, patients still continue to suffer from complications that are wide ranging. One of the major complications is stroke whose prevalence ranges from approximately 2% to 4.6%. Further, such strokes, delirium, and impairments in the cognitive functions of the patients following surgery are responsible for significant morbidity and mortality.
Unfortunately, the above remain common complications that may not get solved during the patients’ lifetime. Several risk factors are associated with the development of stroke after open-chest valve surgery. Such risk factors include advanced age, being female, and calcification of the aorta, preexisting atrial fibrillation, and a positive history of a cerebrovascular accident. Additionally, factors such as being obese, having diabetes mellitus, vascular pathology and the cessation of treatment with pharmacologic agents before surgery get implicated in the causation of such stroke. Preventive measures are available to control the occurrence of post-surgical cerebrovascular accidents. Such precautions include the early detection and treatment of arrhythmias, avoiding the manipulation and cannulation of the aorta, and avoiding hyperglycemia.
Works cited
Abah, Udo and Stephen, Large. "Stroke Prevention in Cardiac Surgery." Interactive Cardiovascular and Thoracic Surgery 15.1 (2012): 155-157. Print.
Berg, Selina Kikkenborg, et al. "Patient experiences of recovery after heart valve replacement: suffering weakness, struggling to resume normality." BMC Nursing 12.1 (2013): 1. Web. 31 May 2016.
Boeken, U et al. "Risk Factors for Stroke after Cardiac Surgery: The Role of Screening Carotid Ultrasonography". The Thoracic and Cardiovascular Surgeon 60.S 01 (2012): n. pag. Web. 31 May 2016.
Cao, Li et al. "Risk Factors for Recurrent Stroke after Coronary Artery Bypass Grafting". J Cardiothoracic Surgery 6.1 (2011): 157. Web. 31 May 2016.
Carnicelli, Anthony. "Anticoagulation for Valvular Heart Disease - American College of Cardiology." American College of Cardiology. N.P., 2015. Web. 31 May 2016.
Casselman, Filip. "Minimally Invasive Heart Valve Surgery." European Society of Cardiology 12.6 (2013): n. pag. Print.
Costa, Mário Augusto Cray da et al. "Risk Factors for Perioperative Ischemic Stroke in Cardiac Surgery". Revista Brasileira de Cirurgia Cardiovascular (2015): n. pag. Web. 31 May 2016.
Daneault, Benoit et al. "Stroke Associated With Surgical and Transcatheter Treatment of Aortic Stenosis". Journal of the American College of Cardiology 58.21 (2011): 2143-2150. Web. 31 May 2016.
Mostafa, Ashraf et al. “Atrial Fibrillation Post Cardiac Bypass Surgery.” Avicenna Journal of Medicine 2.3 (2012): 65–70. PMC. Web. 1 June 2016.
Kato, Norman S. "Heart Valve Surgery: MedlinePlus Medical Encyclopedia". Nlm.nih.gov. N.P., 2016. Web. 31 May 2016.
Lucà, Fabiana et al. "Minimally Invasive Mitral Valve Surgery: A Systematic Review". Minimally Invasive Surgery 2013 (2013): 1-10. Web. 31 May 2016.
Messe, S. R. et al. "Stroke after Aortic Valve Surgery: Results from a Prospective Cohort". Circulation 129.22 (2014): 2253-2261. Web. 31 May 2016.
Neragi-Miandoab, Siyamek and Robert E. Michler. "A Review of Most Relevant Complications of Transcatheter Aortic Valve Implantation." ISRN Cardiology 2013 (2013): 1-12. Web. 31 May 2016.
Whitlock, Richard et al. “Predictors of Early and Late Stroke Following Cardiac Surgery.” CMAJ : Canadian Medical Association Journal 186.12 (2014): 905–911. PMC. Web. 1 June 2016.
