Acute Aortic Disease.. - Index of

Acute Aortic Dissection 239
concern about involvement of the brachiocephalic trunk, or significantly higher
blood pressure measurements from the left arm, then a left radial arterial line
should be placed (37). Because hemodynamic deterioration may occur abruptly,
an intravenous access different from that used for drug infusions should be
readily available. Antithrombotic medications (e.g., heparin and fibrinolytics),
commonly used in other chest pain syndromes, should be withheld until the
diagnosis of dissection is ruled out, as their administration may have catastrophic
consequences. Pain contributes to a hyperadrenergic state with worsening of
tachycardia and hypertension, and should be eliminated promptly by the intravenous
administration of morphine sulfate, a drug with additional blood pressure
lowering effects.
Medical management largely varies depending on the patient’s hemodynamic
status (Fig. 6). A normotensive or hypotensive patient requires close
evaluation for heart failure (due to concomitant aortic insufficiency or myocardial
ischemia), blood loss, and pericardial tamponade, prior to the administration of
volume. Hypotension or shock constitute signs of ominous prognosis (74) and
should usually be treated with volume resuscitation. A patient with significant
hemodynamic instability may require intubation and mechanical ventilation. In the
case of tamponade, pericardiocentesis appears to be contraindicated, based on a
small series in which three of four patients completing the procedure successfully
subsequently developed electromechanical dissociation and death within 40 minutes
(75). This may be due to acute rebound of arterial pressure or increase in the
pressure gradient between the false lumen and the intrapericardial space, favoring
new bleeding, after correction of the tamponade. Immediate bedside sternotomy for
surgical access to the ascending aorta has been suggested in some cases of tamponade,
but remains controversial (65). Cornerstones in the medical management of
hypertensive and most normotensive patients with suspected acute aortic dissection
are anti-impulse therapy and blood pressure control, with a target systolic blood
pressure of 100–120 mmHg or mean arterial pressure of 60–75 mmHg (37,46).
Pharmacological Therapy
Short-acting intravenous agents are preferred to facilitate titration to blood
pressure goals, both in the intensive care unit and the operating room. In patients
who are normotensive and clinically stable (at presentation or after intravenous
therapy) and who are not undergoing intervention, oral drugs can be started as a
preliminary step before discharge. Table 1 summarizes pharmacologic properties
of intravenous drugs commonly used in the management of acute aortic dissection
and Table 2 is a summary of advantages and disadvantages of the different drugs.
Beta Blockers
The initial agent of choice in most cases should be an intravenous beta blocker.
Beta blockers have the dual advantage of decreasing dp/dt max as well as lowering
blood pressure. They are contraindicated in patients with significant bradycardia