Medication Summary
The goals of pharmacotherapy are to reduce morbidity and to prevent complications. Antihypertensive agents are used to reduce tension on the vessel wall in patients with abdominal aortic aneurysms (AAAs) who have elevated blood pressure (BP). Analgesics are also an important element of care.
Antihypertensives
Class Summary
Antihypertensives are used to reduce the rate of rise of the aortic pressure (dP/dt). For acute reduction of arterial pressure, the potent vasodilator sodium nitroprusside is very effective. To reduce dP/dt acutely, administer a beta blocker intravenously (IV) in incremental doses until a heart rate of 60-80 beats/min is attained. When beta blockers are contraindicated, as in second- or third-degree atrioventricular block, consider using calcium-channel blockers.
Esmolol (Brevibloc)
An ultrashort-acting beta1 blocker, esmolol is particularly useful in patients with elevated arterial pressure, especially if surgery is planned. It can be discontinued abruptly if necessary. This agent is normally used in conjunction with nitroprusside. It may be useful as a means of testing beta-blocker safety and tolerance in patients with a history of obstructive pulmonary disease who are at uncertain risk for bronchospasm from beta blockade. The elimination half-life of esmolol is 9 minutes.
Labetalol (Trandate)
Labetalol blocks alpha1-, beta1-, and beta2-adrenergic receptor sites, decreasing blood pressure.
Propranolol (Inderal LA, InnoPran XL)
A class II antiarrhythmic nonselective beta-adrenergic receptor blocker, propranolol has membrane-stabilizing activity and decreases the automaticity of contractions. It is not suitable for emergency treatment of hypertension; it should not be administered IV in hypertensive emergencies.
Metoprolol (Lopressor, Toprol-XL)
Metoprolol is a selective beta 1-adrenergic receptor blocker that decreases the automaticity of contractions. During IV administration, carefully monitor blood pressure, heart rate, and electrocardiograms. When considering conversion from IV to oral (PO) dosage forms, use the ratio of 2.5 mg PO to 1 mg IV.
Nitroprusside (Nitropress)
Nitroprusside causes peripheral vasodilation by acting directly on venous and arteriolar smooth muscle, thus reducing peripheral resistance. This agent is commonly used IV because of its rapid onset and short duration of action. It is easily titrated to the desired effect.
Because nitroprusside is light-sensitive, both bottle and tubing should be wrapped in aluminum foil. Before initiating nitroprusside therapy, administer a beta blocker to counteract the physiologic response of reflex tachycardia that occurs when nitroprusside is used alone. This physiologic response will increase the shear forces against the aortic wall, thus increasing dP/dt. The objective is to keep the heart rate between 60 and 80 beats/min.
Analgesics
Class Summary
Pain control is essential to quality patient care. It ensures patient comfort, promotes pulmonary toilet, and prevents exacerbation of tachycardia and hypertension.
Morphine sulfate (Astramorph, Infumorph, Duramorph)
Morphine is the drug of choice for narcotic analgesia because of its reliable and predictable effects, safety profile, and ease of reversibility with naloxone. Like fentanyl, morphine sulfate is easily titrated to the desired level of pain control. Morphine sulfate administered IV may be dosed in a number of ways. It is commonly titrated until the desired effect is obtained.
Fentanyl citrate
Fentanyl citrate is a synthetic opioid that has 75-200 times more potency of and a much shorter half-life than morphine sulfate. It has fewer hypotensive effects than morphine and is safer in patients with hyperactive airway disease because of minimal or no associated histamine release. By itself, fentanyl citrate causes little cardiovascular compromise, although the addition of benzodiazepines or other sedatives may result in decreased cardiac output and blood pressure.
Fentanyl citrate is highly lipophilic and protein-bound. Prolonged exposure to it leads to accumulation of the drug in fat and delays the weaning process. Consider continuous infusion because of the medication's short half-life.
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Radiograph shows calcification of abdominal aorta. Left wall is clearly depicted and appears aneurysmal; however, right wall overlies spine.
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On radiography, lateral view clearly shows calcification of both walls of abdominal aortic aneurysm, allowing diagnosis to be made with certainty.
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CT demonstrates abdominal aortic aneurysm (AAA). Aneurysm was noted during workup for back pain, and CT was ordered after AAA was identified on radiography. No evidence of rupture is seen.
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Arteriography demonstrates infrarenal abdominal aortic aneurysm. This arteriogram was obtained in preparation for endovascular repair of aneurysm.
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Lateral arteriogram demonstrates infrarenal abdominal aortic aneurysm. Demonstration of superior mesenteric artery, inferior mesenteric artery, and celiac artery on lateral arteriogram is important for complete evaluation of extent of aneurysm.
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Arteriogram after successful endovascular repair of abdominal aortic aneurysm.
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Ultrasonogram from patient with abdominal aortic aneurysm (AAA). This aneurysm was best visualized on transverse or axial image. Patient underwent conventional AAA repair.
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MRI of 77-year-old man with leg pain believed to be secondary to degenerative disk disease. During evaluation, abdominal aortic aneurysm was discovered.
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Age is risk factor for development of aneurysm.
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Inflammation, thinning of media, and marked loss of elastin.
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Pulsatile abdominal mass.
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Aneurysm with retroperitoneal fibrosis and adhesion of duodenum.
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Aortic endoprosthesis (Cook aortic and aortobi-iliac endograft).
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Endoaneurysmorrhaphy
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Endovascular grafts.
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Atheroemboli from small abdominal aortic aneurysms produce livedo reticularis of feet (ie, blue toe syndrome).
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Enhanced spiral CT scans with multiplanar reconstruction and CT angiogram.
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Angiography is used to diagnose renal area. In this instance, endoleak represented continued pressurization of sac.
Tables
Lowest Risk |
Moderate Risk |
High Risk |
Age < 70 y |
Age 70-80 y |
Age 80 y |
Physically active |
Active |
Inactive, poor stamina |
No clinically overt cardiac disease |
Stable coronary disease; remote MI; LVEF >35% |
Significant coronary disease; recent MI; frequent angina; CHF; LVEF < 25% |
No significant comorbidities |
Mild COPD |
Limiting COPD; dyspnea at rest; O2 dependency; FEV1< 1 L/sec |
... |
Creatinine 2.0-3.0 mg/dL |
... |
Normal anatomy |
Adverse anatomy or AAA characteristics |
Creatinine >3 mg/dL |
No adverse AAA characteristics |
... |
Liver disease (↑PT; albumin < 2 g/dL) |
Anticipated operative mortality, 1-3% |
Anticipated operative mortality, 3-7% |
Anticipated operative mortality, at least 5-10%; each comorbid condition adds ~3-5% mortality risk |
AAA = abdominal aortic aneurysm; CHF = chronic heart failure; COPD = chronic obstructive pulmonary disease; FEV1 = forced expiratory volume in 1 second; LVEF = left ventricular ejection fraction; MI = myocardial infarction; PT = prothrombin time. |
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AAA Diameter (cm) |
Rupture Risk (%/y) |
< 4 |
0 |
4-5 |
0.5-5 |
5-6 |
3-15 |
6-7 |
10-20 |
7-8 |
20-40 |
>8 |
30-50 |
AAA = abdominal aortic aneurysm. |
|
Factor |
Low Risk |
Average Risk |
High Risk |
Diameter |
< 5 cm |
5-6 cm |
>6 cm |
Expansion |
< 0.3 cm/y |
0.3-0.6 cm/y |
>0.6 cm/y |
Smoking/COPD |
None, mild |
Moderate |
Severe/steroids |
Family history |
No relatives |
One relative |
Numerous relatives |
Hypertension |
Normal blood pressure |
Controlled |
Poorly controlled |
Shape |
Fusiform |
Saccular |
Very eccentric |
Wall stress |
Low (35 N/cm2 |
Medium (40 N/cm2 |
High (45 N/cm2) |
Sex |
... |
Male |
Female |
COPD = chronic obstructive pulmonary disease. |
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