Acute Aortic Disease.. - Index of

Acute Aortic Dissection 249
DISSCUSSION AND COMMENTARY
Questions for the Authors
Should aggressive vasodilator treatment be initiated as the first line of therapy in
hypertensive patients with acute aortic dissection?
No, as discussed in the text, vasodilator therapy should only be initiated after
aggressive intravenous beta blockade has been completed, to prevent rebound
tachycardia and increases in dp/dtmax.
Should a patient with normal blood pressure and heart rate still receive medical
therapy?
Yes, because, at least in experimental models, there is a threshold of dp/dtmax below
which dissection does not progress, so one of the goals of therapy should be to
reduce cardiac impulse even in normotensive, nontachycardic patients. In addition,
adequate beta blockade may help prevent normal daily variations in heart rate and
blood pressure that may be unnoticed but still potentially harmful.
Should complications of acute aortic dissection be managed for other critically ill
cardiac patients?
No. In the event of tamponade, pericardiocentesis appears to be contraindicated,
based on a small series (75). This study found that most aortic dissection patients
with tamponade successfully undergoing pericardiocentesis subsequently died in
less than an hour, presumably due to acute rebound of arterial pressure or increase
in the pressure gradient between the false lumen and the pericardial space.
In a patient with acute dissection and tamponade, should “partial” pericardiocentesis
be attempted?
This is a controversial issue. As discussed in the text, pericardiocentesis has been
associated with sudden hemodynamic deterioration and death, probably because
of recurrent intra-pericardial bleeding. However, if the tamponade is so severe as to
cause organ hypoperfusion, a reasonable compromise may be to attempt drainage of
the minimum amount of fluid necessary to increase blood pressure to a tolerable
level, without excessively decompressing the intrapericardial cavity (75). It is important
to acknowledge that the possibility of hemodynamic collapse still remains.
Should a Swan–Ganz catheter be placed?
Monitoring left ventricular filling pressures may be useful to guide therapy,
particularly in patients developing congestive heart failure (e.g., in the setting of
acute aortic regurgitation) or in whom large amounts of fluid are administered.
Although evidence in the particular context of aortic dissection is lacking, we
may extrapolate from recent randomized trials in heart failure or the intensive
care unit that systematic use of Swan–Ganz catheters is neither useful nor detrimental
(95,96). Placement of a pulmonary catheter should not be allowed to
delay implementation of urgent medical therapy or prompt imaging or other
vital testing.