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Echocardiography

2015-04-01 01:18 毕业

Anesthetic considerations of descending thoracic aortic aneurysm repair
Yong G Peng, M.D., Ph.D.
Director of Cardiothoracic Anesthesia Fellowship Program
Director of Intraoperative Transesophageal Echocardiography (TEE)
Department of Anesthesiology, University of Florida, Gainesville, Florida
The prevalence of thoracic aortic aneurysms appears to have increased in recent years.
This may be due to either an increase in the elderly patient population or an improvement
in diagnostic modalities. Thoracic aortic aneurysms are now estimated to affect 10 of
every 100,000 elderly adults, one third of which involve the descending portion of the
thoracic aorta (1-4). Despite recent improvements in surgical and organ preservation
techniques, surgical repair of the descending thoracic aortic aneurysms (DTAAs) as well
as thoracoabdominal aortic aneurysms (TAAAs) are still highly invasive procedures with
a substantial rate of mortality and permanent neurological injury including paraplegia.
Some studies have suggested that there is a 30% risk of rupture in 5 years when a TAAA
is >6cm. Given the significant rupture rates and high mortality with rupture, the repair of
DTAAs or TAAAs seems warranted in acceptable risk patients (Figure 1). For the
patients who have a degenerative or chronic aneurysm, elective repair of the descending
thoracic aortic pathologies is advisable if the aneurysms exceeds 5 to 6 cm in diameter or
if symptoms are present, especially for the patient who has type B (DeBakey type III)
aortic dissections or Marfan's syndrome (1-3).
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Open surgical repair of DTAAs is still considered to be the "conventional" standard
reference treatment despite availability of alternative options like endoluminal stent
therapy (4-7). This operation presents the surgeons and anesthesiologists with a
multitude of technical and cognitive challenges throughout the intraoperative period. It

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also bears significant perioperative morbidity and mortality. In a large series analysis,
mortality rates of 5.-8.8 % and paraplegia rates of 2.7-14.3% were reported (5). The
highly invasive nature of the open surgical procedure and prolonged recovery period
make an endovascular repair a highly attractive alternative approach for DTAA (4,5,7).
In 1991, Parodi and colleagues reported the first successful abdominal aortic aneurysm
repair with an endoluminal stent and subsequent thoracic aortic repair, which opened a
new era for minimally invasive approaches for aortic pathologies (4,7) (Table 1).
Endovascular therapy has provided alternative treatment options for high risk patients
who were previously denied for open surgical repair due to comorbidity illnesses.
Although the endovascular approach offers a lower perceived morbidity and "speedy"
recovery for the repair of DTAA, it has its own potential problems and deals with the
refinement process (4,5,7). There are several major complications that are associated
with endovascular therapy including a relatively high rate of endoleaks requiring re-
intervention, paraplegia, stroke, stent migration and fracture, iatrogenic aortic injury, and
a high incidence of peripheral vascular complication (4). Despite the theoretical
advantage of endovascular thoracic stent therapy, there is no data that support a survival
rate advantage in endoluminal stent repairs versus open surgical repair for DTAA (4,5).
There are a variety of other factors that preclude the use of endovascular procedures as an
option for DTAAs or TAAAs repair. These include severe aortic atheromatous disease,
hemodynamically unstable ruptured aneurysm, tortuous aorta, compound aortic angles,
aneurysms extended into or in close proximity to aortic arch vessels and lack of a
"landing zone" for the stent (2,4). The focuses of this presentation will be on open
surgical repair of DTAAs, because there is an extensive involvement by the （科教范文网http://fw.ΝsΕΑc.com编辑）
anesthesiologist during the intraoperative period of open surgical repair of DTAA relative
to the endovascular approach. The current literature on anesthetic consideration for
surgical repair of DTAA and also some of our experiences in reducing complications of
DTAA repair at the University of Florida will be shared
Figure 1 Schematic classification of descending thoracic aortic aneurysm. Cited from (6)
Postoperative outcomes with open surgical repair and endovascular stent therapy
Procedure Paraplegia Stroke Post-
operative
MI
Renal
failure
Respiratory
failure
Length of
hospital
stay (days)
2 year
overall
survival
Open surgical
repair
14% 4% 1% 13% 20% 14.4 + 12.8 76%
Endoluminal
stent therapy
3% 4% 0% 1% 4% 7.4 + 17.7 78%
P value 0.003 1.00 0.4 0.01 <0.001 <0.001 0.48
Summarized information in the table cited from a multicenter comparative trial (4)
References:
1) Kouchoukos NT and Dougenis D: Surgery of the thoracic aorta N Engl J Med 1997;
336(26):1876-88.
2) Shine TSJ and Murray MJ: Intraoperative management of aortic aneurysm surgery.
Anesthesiol Clin N Am 2004; 22:289-305
3) Black JH and Cambria RP: Current results of open surgical repair of descending
thoracic aortic aneurysms. J Vasc Surg 2006; 43(suppl):6A-11A
4) Bavaria JE, Appoo JJ, Makaroun MS, Verter J, Yu ZF, and Mitchell RS:
Endovascular stent grafting versus open surgical repair of descending thoracic aortic
aneurysms in low-risk patients: A multicenter comparative trial. J Thorac Cardiovasc
Surg 2007; 133:369-377
5) Glade GJ, Vahl AC, Wisselink W, Linsen MAM, and Balm R: Mid-term survival and
costs of treatment of patients with descending thoracic aortic aneurysms; endovascular vs.
open repair: a case-control study. Eur J Vasc Endovasc Surg 2005; 29:28-34
6) Huynh TTT, Statius van Eps RG, Miller CC, Villa MA, Estrera AL, Azizzadeh A ,
Porat EE, Goodrick JS, and Safi HJ: Glomerular filtration rate is superior to serum

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creatinine for prediction of mortality after thoracoabdominal aortic surgery. 2005; J Vasc
Surg 42:206-212
7) Patel HJ, Williams DM, Upchurch GR, Shillingford MS, Dasika NL, Proctor MC and
Deeb GM: Long-term results from a 12-year experience with endovascular therapy for
thoracic aortic disease. 2006; Ann Thorac Surg 82:2147-2153