You have to be able to sign in to Medscape to read this so I am copying and pasting this article. These are the guidelines our caregivers are being taught. I hope it will be of help to someone here.
Thoracoaortic Aneurysms and Dissections: Guidance for the Primary Care Clinician CE
Marilyn W. Edmunds, PhD, NP
Disclosures
Thoracoaortic Aneurysms and Dissections
Aortic aneurysms are regarded ominously by clinicians. New technologies and new materials are now used successfully in endovascular repair and have given new hope to patients with these problems. Erin L. Davis, CRNP, from the Hospital of the University of Pennsylvania Aortic Surgery Program, discussed some of the current surgical procedures they are offering. This is an aortic referral center, and they see over 300 cases a year with aortic disease.[1]
As with many problems, if the clinician doesn't understand the anatomy of the problem, the proper diagnosis cannot be made. As primary care providers often make the initial findings of aneurysm, it is essential that they are precise about the location of the aneurysm in making a surgical referral. Problems of the aorta are classified into the 4 structural parts of the aorta:
Aortic root -- the first 2-3 inches of the aorta above the aortic valve; anterior mediastinum; right and left coronary arteries emerge from the aortic root
Aortic arch -- large branch vessels originate here (innominate, left common carotid, and left subclavian arteries)
Descending aorta -- begins distal to the left subclavian artery extending to the diaphragmatic; posterior mediastinum
Abdominal aorta -- diaphragmatic hiatus to distal bifurcation.[2]
The 2 major problems in the aorta result from either aneurysms or dissections -- 2 very different processes. Aortic aneurysms are present when there is a place in the aorta where the aortic diameter is greater than 5.0 cm or twice the expected normal diameter. (The normal thoracic aortic diameter is 2.5 to 3.7 cm). The aneurysms are classified as either saccular or fusiform and further classified by location and extent of aortic involvement (root, arch, descending, or thoracoabdominal). A saccular aneurysm involves an outpouching of the circumference of the aortic wall. The fusiform aneurysm involves dilation of the whole blood vessel wall for the localized extent of the dilation. These conditions often result from connective tissue disease, inflammatory disease, hypertension, bicuspid aortic valve syndrome, smoking, atherosclerosis, or infectious disease.
Aortic dissection is defined as an intimal tear that allows blood to enter the media, which causes a split (dissection), creating a new channel called the false lumen. This tear can result in malperfusion and loss of aortic valve support. Aortic dissections are classified based on anatomic location. In addition, a Type A aortic dissection is an acute or chronic intimal tear in the aorta that originates in the ascending aorta and can extend into the descending aorta. Patients say that they feel a tear and experience very severe chest pain. They may have associated myocardial ischemia, infarction, or tamponade. Initial dissection may extend even lower.
In contrast, a Type B aortic dissection is an acute or chronic intimal tear in the aorta that originates in the descending aorta and can extend into the iliac arteries. These individuals may present with back or chest pain, abdominal pain (less common), and peripheral ischemia. If uncomplicated, patients may be treated with medical management. In an uncomplicated Type B dissection, the mortality is lower with medical management than with surgical intervention.[3]
Thoracic aortic aneurysms were linked to a 60% to 75% mortality rate 25 years ago. More than 50% of patients died from aortic rupture. Thoracoaortic surgery programs throughout the nation have improved these numbers. Research has now suggested that the risk of rupture may be calculated and the candidates for surgery more clearly determined based on the size of the aneurysm. The current findings[4-6] suggest that:
Median size at rupture for ascending aortic aneurysm was 6.0 cm;
Median size at rupture for a thoracic aortic arch aneurysm (TAAA) was 7.2 cm;
If one waits for the aneurysm to reach 6.0 or 7.0 cm, nearly half of patients will be lost; and
Sizes of 5.5 cm (ascending) or 6.5 cm TAAA mandates surgery.
An aortic aneurysm may rupture without dissection. When dissection takes place, it is classified into 2 types: Stanford Type A is a surgical emergency. Type A aortic dissection carries a surgical mortality of approximately 25%. The mortality of medical management of Type A dissection reaches nearly 60%.[7] Causes of death include heart failure from acute aortic insufficiency, aortic rupture, malperfusion of arch vessels leading to stroke, and nonperfusion of coronary arteries leading to myocardial infarction. Stanford Type B that is uncomplicated has a 30-day mortality rate of 3%. Complicated dissection carries a 20% mortality in the first 2 days following presentation. Thus, the treatment strategy to either do surgery or monitor patients who present with aortic disease is determined by the risk:benefit analysis for that particular problem.[5,7]
The risk of either rupture or dissection is increased in the presence of certain risk factors: Marfan/annuloaortic ectasia, dissected aorta (residual Type B dissection), rate of growth of aneurysm, presence of mural thrombus, smoking, and uncontrolled hypertension.
Many aortic aneurysms are diagnosed incidental to other conditions. However, once it is detected, its presence requires a careful evaluation. History should include past medical history, past surgical history, history of trauma, and family history. Chest or back pain in the left scapular area, shortness of breath, fatigue, and symptoms of dysphagia or hoarseness are important to note in the review of systems. A complete physical examination may reveal a pulsatile abdominal mass, aortic stenosis or aortic insufficiency murmurs, or even signs of a cerebrovascular accident (CVA). A computed tomography (CT) scan of the chest or chest/abdomen with contrast is the "gold standard" radiographic examination. Magnetic resonance angiography may be used in patients who cannot have contrast CT scan. Echocardiography (ECHO) may be helpful in evaluating the root or the specific site of ascending aneurysms.
Surgical repair of an aortic aneurysm involves resection of the aneurysmal portion of the aorta and replacing that portion with Dacron tube graft. When the aortic root is involved and the valve must be replaced as well, there are additional conduits available to the surgeon. Patients may chose between mechanical or biological prostheses, just as they can with a straightforward valve replacement. These conduits include pig root, pericardial composite (bovine pericardial valve attached to Dacron graft by the surgeon), and mechanical composite graft (mechanical valve attached to Dacron tube graft). Patients who require valve replacement must choose the valve conduit prior to surgery. The mechanical prosthesis requires warfarin and should, in theory, last the patient a lifetime. Biological prostheses spare the need for lifelong anticoagulation but will require replacement in 15-25 years. Less commonly used is homografting, the transplantation of an organ or tissue from one individual to another.[7]
Surgical Procedures for Aneurysms
The different anatomic location of aneurysms dictates different surgical procedures.[2]
Aortic Root and Ascending Aortic Aneurysms
These may involve the root, ascending, and proximal arch.
Aortic valve involvement may be present.
Consider bicuspid aortic valve.
Patients require aggressive blood pressure control (goal systolic blood pressure [SBP] less than 130 mm Hg).
Patients should be restricted from lifting things weighing more than 30-50 lb.
Aortic surveillance with serial imaging is required: CT scan with contrast of chest or chest/abdomen or magnetic resonance imaging (MRI) if patient's clinical history dictates every 6 months. They may also require an ECHO. If the aneurysm increases by 0.5 cm per year, they probably will need surgery.
Surgical intervention is dictated by the anatomic location of the aneurysm or the extent of dilatation, the absolute diameter, the growth rate of the diameter, aortic valve function, left ventricular (LV) diameters and LV function in aortic valve disease, and a calculated risk:benefit ratio to determine which is higher, the risk of rupture/dissection or the natural history.
Surgical triggers would be a 4.5-cm maximal diameter with Marfan syndrome or positive family history of rupture/dissection; 5.0-cm maximal diameter with moderate or worse arteriovenous disease; 5.5-cm maximal diameter regardless of other conditions; acute or chronic dissection (more than 2 weeks); positive growth rate of 0.5 cm/year.
Aortic Arch Aneurysms
These generally present as saccular aneurysms.
It is more difficult to predict rupture patterns with this presentation.
Given the surgical risk, providers may allow the patient to reach a larger diameter prior to intervention.
The medical management for these individuals includes:
Assessing for neurologic status;
Assessing for hoarseness and dysphagia;
Blood pressure control;
Lifting restrictions; and
Serial imaging.
Candidates selected for surgery undergo an open procedure.
Standard surgery would include a sternotomy with 4-branch graft and complex perfusion strategies for neurocerebral protection.
A hybrid procedure, which is not yet approved, is growing in popularity as an alternative. This requires sternotomy with bypass from ascending aorta to arch vessels and endovascular exclusion of aortic arch.
Surgical complications include neurologic changes, CVA, paralyzed vocal cord, and dysphagia.
Descending Aorta or Thoracoabdominal Aortic Aneurysms
These aneurysms require aggressive blood pressure control to keep SBP below 130 mm Hg, lifting restrictions, and aortic surveillance with serial imaging (CT scan with contrast of chest or chest/abdomen or MRI if patient's clinical history dictates), and ECHO
Evaluation would require pulmonary function tests, pulse volume recordings, carotid ultrasound, ECHO, and a cardiac stress test.
Surgical intervention would be dictated by anatomic location of aneurysm or dilation, absolute diameter, growth rate, aortic valve function, LV diameters and LV function in aortic valve disease, and based on risk/benefit ratio.
Indications for surgery for descending thoracic and thoracoabdominal aneurysms include the presence of Marfan syndrome with more than 5.5-cm aneurysm; any aneurysm more than 6.5 cm; increase in growth rate when aneurysm is more than 6.0 cm; and rupture or false aneurysm.
The surgical intervention has been an open repair with a left thoracectomy or thoracoabdominal incision in which the aneurysm is replaced by Dacron tube graft, use of cardiopulmonary bypass , with a lengthy (and painful) recovery.
A relatively new surgical intervention involves endovascular repair with a stent graft repair via femoral artery or retroperitoneal incision. This procedure may be used in descending thoracic aneurysms but is not indicated in TAAA. It requires having an appropriate "landing zone" -- enough space to be able to install the graft. This allows the graft to seal with radial force. This procedure is approved in aortic aneurysm; in aortic dissection, it is off label but is beginning to be seen.
There is a potential for some serious complications for descending/TAAA repair as the aorta contributes to spinal cord perfusion through intercostal arteries. Thus, paralysis (transient or permanent) may be seen. Stroke, dysphagia, vocal cord paralysis, and pulmonary failure are other potential problems.
In the postoperative patient, clinicians must worry about low blood pressure, not high blood pressure. Blood pressure must be high enough to provide good spinal cord perfusion. Serial neurologic monitoring should track the patient's ability to lift their legs.
Aneurysms are a good example of a condition that warrants excellent communication between primary care provider and specialty surgeon. When patients with aneurysms or dissections are being monitored in the community, the primary care clinician must understand the changes in patient condition that would prompt re-evaluation and surgery. The patient must also understand that while they may be cared for in the community for many of their health problems, they should probably be a patient of the thoracic aortic surgery staff for the rest of their lives. Both groups should work together and communicate clearly to each other and their patients.
Thoracoaortic Aneurysms and Dissections: Guidance for the Primary Care Clinician CE
Marilyn W. Edmunds, PhD, NP
Disclosures
Thoracoaortic Aneurysms and Dissections
Aortic aneurysms are regarded ominously by clinicians. New technologies and new materials are now used successfully in endovascular repair and have given new hope to patients with these problems. Erin L. Davis, CRNP, from the Hospital of the University of Pennsylvania Aortic Surgery Program, discussed some of the current surgical procedures they are offering. This is an aortic referral center, and they see over 300 cases a year with aortic disease.[1]
As with many problems, if the clinician doesn't understand the anatomy of the problem, the proper diagnosis cannot be made. As primary care providers often make the initial findings of aneurysm, it is essential that they are precise about the location of the aneurysm in making a surgical referral. Problems of the aorta are classified into the 4 structural parts of the aorta:
Aortic root -- the first 2-3 inches of the aorta above the aortic valve; anterior mediastinum; right and left coronary arteries emerge from the aortic root
Aortic arch -- large branch vessels originate here (innominate, left common carotid, and left subclavian arteries)
Descending aorta -- begins distal to the left subclavian artery extending to the diaphragmatic; posterior mediastinum
Abdominal aorta -- diaphragmatic hiatus to distal bifurcation.[2]
The 2 major problems in the aorta result from either aneurysms or dissections -- 2 very different processes. Aortic aneurysms are present when there is a place in the aorta where the aortic diameter is greater than 5.0 cm or twice the expected normal diameter. (The normal thoracic aortic diameter is 2.5 to 3.7 cm). The aneurysms are classified as either saccular or fusiform and further classified by location and extent of aortic involvement (root, arch, descending, or thoracoabdominal). A saccular aneurysm involves an outpouching of the circumference of the aortic wall. The fusiform aneurysm involves dilation of the whole blood vessel wall for the localized extent of the dilation. These conditions often result from connective tissue disease, inflammatory disease, hypertension, bicuspid aortic valve syndrome, smoking, atherosclerosis, or infectious disease.
Aortic dissection is defined as an intimal tear that allows blood to enter the media, which causes a split (dissection), creating a new channel called the false lumen. This tear can result in malperfusion and loss of aortic valve support. Aortic dissections are classified based on anatomic location. In addition, a Type A aortic dissection is an acute or chronic intimal tear in the aorta that originates in the ascending aorta and can extend into the descending aorta. Patients say that they feel a tear and experience very severe chest pain. They may have associated myocardial ischemia, infarction, or tamponade. Initial dissection may extend even lower.
In contrast, a Type B aortic dissection is an acute or chronic intimal tear in the aorta that originates in the descending aorta and can extend into the iliac arteries. These individuals may present with back or chest pain, abdominal pain (less common), and peripheral ischemia. If uncomplicated, patients may be treated with medical management. In an uncomplicated Type B dissection, the mortality is lower with medical management than with surgical intervention.[3]
Thoracic aortic aneurysms were linked to a 60% to 75% mortality rate 25 years ago. More than 50% of patients died from aortic rupture. Thoracoaortic surgery programs throughout the nation have improved these numbers. Research has now suggested that the risk of rupture may be calculated and the candidates for surgery more clearly determined based on the size of the aneurysm. The current findings[4-6] suggest that:
Median size at rupture for ascending aortic aneurysm was 6.0 cm;
Median size at rupture for a thoracic aortic arch aneurysm (TAAA) was 7.2 cm;
If one waits for the aneurysm to reach 6.0 or 7.0 cm, nearly half of patients will be lost; and
Sizes of 5.5 cm (ascending) or 6.5 cm TAAA mandates surgery.
An aortic aneurysm may rupture without dissection. When dissection takes place, it is classified into 2 types: Stanford Type A is a surgical emergency. Type A aortic dissection carries a surgical mortality of approximately 25%. The mortality of medical management of Type A dissection reaches nearly 60%.[7] Causes of death include heart failure from acute aortic insufficiency, aortic rupture, malperfusion of arch vessels leading to stroke, and nonperfusion of coronary arteries leading to myocardial infarction. Stanford Type B that is uncomplicated has a 30-day mortality rate of 3%. Complicated dissection carries a 20% mortality in the first 2 days following presentation. Thus, the treatment strategy to either do surgery or monitor patients who present with aortic disease is determined by the risk:benefit analysis for that particular problem.[5,7]
The risk of either rupture or dissection is increased in the presence of certain risk factors: Marfan/annuloaortic ectasia, dissected aorta (residual Type B dissection), rate of growth of aneurysm, presence of mural thrombus, smoking, and uncontrolled hypertension.
Many aortic aneurysms are diagnosed incidental to other conditions. However, once it is detected, its presence requires a careful evaluation. History should include past medical history, past surgical history, history of trauma, and family history. Chest or back pain in the left scapular area, shortness of breath, fatigue, and symptoms of dysphagia or hoarseness are important to note in the review of systems. A complete physical examination may reveal a pulsatile abdominal mass, aortic stenosis or aortic insufficiency murmurs, or even signs of a cerebrovascular accident (CVA). A computed tomography (CT) scan of the chest or chest/abdomen with contrast is the "gold standard" radiographic examination. Magnetic resonance angiography may be used in patients who cannot have contrast CT scan. Echocardiography (ECHO) may be helpful in evaluating the root or the specific site of ascending aneurysms.
Surgical repair of an aortic aneurysm involves resection of the aneurysmal portion of the aorta and replacing that portion with Dacron tube graft. When the aortic root is involved and the valve must be replaced as well, there are additional conduits available to the surgeon. Patients may chose between mechanical or biological prostheses, just as they can with a straightforward valve replacement. These conduits include pig root, pericardial composite (bovine pericardial valve attached to Dacron graft by the surgeon), and mechanical composite graft (mechanical valve attached to Dacron tube graft). Patients who require valve replacement must choose the valve conduit prior to surgery. The mechanical prosthesis requires warfarin and should, in theory, last the patient a lifetime. Biological prostheses spare the need for lifelong anticoagulation but will require replacement in 15-25 years. Less commonly used is homografting, the transplantation of an organ or tissue from one individual to another.[7]
Surgical Procedures for Aneurysms
The different anatomic location of aneurysms dictates different surgical procedures.[2]
Aortic Root and Ascending Aortic Aneurysms
These may involve the root, ascending, and proximal arch.
Aortic valve involvement may be present.
Consider bicuspid aortic valve.
Patients require aggressive blood pressure control (goal systolic blood pressure [SBP] less than 130 mm Hg).
Patients should be restricted from lifting things weighing more than 30-50 lb.
Aortic surveillance with serial imaging is required: CT scan with contrast of chest or chest/abdomen or magnetic resonance imaging (MRI) if patient's clinical history dictates every 6 months. They may also require an ECHO. If the aneurysm increases by 0.5 cm per year, they probably will need surgery.
Surgical intervention is dictated by the anatomic location of the aneurysm or the extent of dilatation, the absolute diameter, the growth rate of the diameter, aortic valve function, left ventricular (LV) diameters and LV function in aortic valve disease, and a calculated risk:benefit ratio to determine which is higher, the risk of rupture/dissection or the natural history.
Surgical triggers would be a 4.5-cm maximal diameter with Marfan syndrome or positive family history of rupture/dissection; 5.0-cm maximal diameter with moderate or worse arteriovenous disease; 5.5-cm maximal diameter regardless of other conditions; acute or chronic dissection (more than 2 weeks); positive growth rate of 0.5 cm/year.
Aortic Arch Aneurysms
These generally present as saccular aneurysms.
It is more difficult to predict rupture patterns with this presentation.
Given the surgical risk, providers may allow the patient to reach a larger diameter prior to intervention.
The medical management for these individuals includes:
Assessing for neurologic status;
Assessing for hoarseness and dysphagia;
Blood pressure control;
Lifting restrictions; and
Serial imaging.
Candidates selected for surgery undergo an open procedure.
Standard surgery would include a sternotomy with 4-branch graft and complex perfusion strategies for neurocerebral protection.
A hybrid procedure, which is not yet approved, is growing in popularity as an alternative. This requires sternotomy with bypass from ascending aorta to arch vessels and endovascular exclusion of aortic arch.
Surgical complications include neurologic changes, CVA, paralyzed vocal cord, and dysphagia.
Descending Aorta or Thoracoabdominal Aortic Aneurysms
These aneurysms require aggressive blood pressure control to keep SBP below 130 mm Hg, lifting restrictions, and aortic surveillance with serial imaging (CT scan with contrast of chest or chest/abdomen or MRI if patient's clinical history dictates), and ECHO
Evaluation would require pulmonary function tests, pulse volume recordings, carotid ultrasound, ECHO, and a cardiac stress test.
Surgical intervention would be dictated by anatomic location of aneurysm or dilation, absolute diameter, growth rate, aortic valve function, LV diameters and LV function in aortic valve disease, and based on risk/benefit ratio.
Indications for surgery for descending thoracic and thoracoabdominal aneurysms include the presence of Marfan syndrome with more than 5.5-cm aneurysm; any aneurysm more than 6.5 cm; increase in growth rate when aneurysm is more than 6.0 cm; and rupture or false aneurysm.
The surgical intervention has been an open repair with a left thoracectomy or thoracoabdominal incision in which the aneurysm is replaced by Dacron tube graft, use of cardiopulmonary bypass , with a lengthy (and painful) recovery.
A relatively new surgical intervention involves endovascular repair with a stent graft repair via femoral artery or retroperitoneal incision. This procedure may be used in descending thoracic aneurysms but is not indicated in TAAA. It requires having an appropriate "landing zone" -- enough space to be able to install the graft. This allows the graft to seal with radial force. This procedure is approved in aortic aneurysm; in aortic dissection, it is off label but is beginning to be seen.
There is a potential for some serious complications for descending/TAAA repair as the aorta contributes to spinal cord perfusion through intercostal arteries. Thus, paralysis (transient or permanent) may be seen. Stroke, dysphagia, vocal cord paralysis, and pulmonary failure are other potential problems.
In the postoperative patient, clinicians must worry about low blood pressure, not high blood pressure. Blood pressure must be high enough to provide good spinal cord perfusion. Serial neurologic monitoring should track the patient's ability to lift their legs.
Aneurysms are a good example of a condition that warrants excellent communication between primary care provider and specialty surgeon. When patients with aneurysms or dissections are being monitored in the community, the primary care clinician must understand the changes in patient condition that would prompt re-evaluation and surgery. The patient must also understand that while they may be cared for in the community for many of their health problems, they should probably be a patient of the thoracic aortic surgery staff for the rest of their lives. Both groups should work together and communicate clearly to each other and their patients.
