From the Journals

Bilateral ACP shown similar to unilateral in arch replacement study

 

Key clinical point: Clinical outcomes were comparable between groups who underwent unilateral or bilateral antegrade cerebral perfusion in total arch replacement for type A aortic dissection.

Major finding: Overall 30-day mortality was 11.6% in the bilateral ACP group vs. 20.7% for unilateral ACP (P =.075).

Data source: Population of 203 patients who had aortic arch replacement surgery for type A aortic dissection between September 2006 and August 2014.

Disclosures: Dr. Tong and coauthors reported having no relevant financial disclosures.

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Still waiting for an answer

The study by Dr. Tong and coauthors adds to the discussion between the “bilateralists” and “unilateralists,” as Jean Bachet, MD, called the two prevailing camps on cerebral perfusion strategies in his invited commentary (J Thorac Cardiovasc Surg. 2017;154:765-6). And while most clinical reports find outcomes similar between the two approaches, the evidence favors the bilateral approach for total arch replacement.

Citing how the study implied mortality and neurologic morbidity rates almost half those for unilateral perfusion, but not reaching statistical significance, Dr. Bachet said, “The statisticians would say that this is only a trend and no proof, but some trends might be indicative, and significance might only be a matter of number in each arm of the comparison.”

Dr. Bachet raised a question about the unilateral approach – that once the arch is opened it takes a minute or so to insert the small balloon canula into the origin of the left carotid artery or divided vessel and start bilateral perfusion. “A major question arises,” said Dr. Bachet: “Why should we expose our patients to any undue risk just to avoid a simple maneuver, to spare a little time, or for any other fancy and questionable reason?”

Cardiologists have raised that question for more than 20 years. Said Dr. Bachet, “We still wait for the answer.”

Dr. Bachet is a cardiac surgeon in Surgenes, France. He reported having no financial relationships to disclose.


 

FROM THE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY

What may be the largest study comparing unilateral and bilateral antegrade cerebral perfusion during total arch replacement for type A aortic dissection has reported that outcomes between the two approaches are comparable, although the bilateral approach showed some advantages during the operation itself, investigators from China reported in the Journal of Thoracic and Cardiovascular Surgery (2017;154:767-75).

The effectiveness of bilateral antegrade cerebral perfusion (b-ACP) vs. unilateral antegrade cerebral perfusion (u-ACP) has been the focus of extensive debate, lead study author Guang Tong, MD, of the Guangzhou (China) General Hospital, and coauthors said. They compared outcomes in six different metrics, ranging from cardiopulmonary bypass time to length of stay (LOS) in the ICU and hospital, in 203 patients with type A aortic dissection who had total aortic arch replacement with hypothermic circulatory arrest over an 8-year period ending in August 2014; 121 had b-ACP and 82 had u-ACP. “The issue of u-ACP vs. b-ACP has been examined in aortic arch surgery, but few reports have focused on type A aortic dissection,” Dr. Tong and coauthors wrote.

They acknowledged that some surgeons are reluctant to use b-ACP because of its complexity, but their study found no increase in cross-clamp time, cardiopulmonary bypass time, or surgery time in the b-ACP group. They cited another reason surgeons give for avoiding b-ACP: the risk of embolic injury caused by canulating the left common carotid artery in an atheromatous aorta. “In the present study, this risk was avoided by attaching the left common carotid artery to the four-branched prosthetic graft for left hemisphere perfusion,” Dr. Tong and coauthors wrote.

Key outcomes that the researchers found not statistically significant were:

  • Overall 30-day mortality (11.6% for b-ACP vs. 20.7% for u-ACP; P = .075).
  • Prevalence of postoperative permanent neurologic dysfunction (8.4% vs. 16.9%; P = .091).
  • Average ICU LOS (16 ± 17.75 days vs. 17 ± 11.5 days, P =.454).
  • Average hospital LOS (26.5 ± 20.6 days vs. 24.8 ± 10.3 days, P = .434).

Dr. Tong and coauthors used an aggressive approach, as advocated by Dhaval Trivedi, MD, and colleagues (Ann Thorac Surg. 2016;101:896-903), and had a total arch replacement rate of 57.8%. This rate is higher than most published series in the west but comparable to other studies from China, perhaps because of the relatively young age of this study cohort – an average age of 51 years – compared to data sets other studies have used. Dr. Tong and coauthors used a b-ACP strategy that established both cerebral perfusion routes before circulatory arrest.

Rates of the following complications were also not significantly different across the study population: paraplegia (2.8% for b-ACP vs. 3.1% for u-ACP), temporary neurologic dysfunction (4.7% vs. 9.2%), permanent neurologic dysfunction (8.4% vs. 16.9%), renal failure (18% vs. 23.1%), reoperation for bleeding (2.8% vs. 4.6%), and mediastinal infection (3.7% vs. 6.2%).

While b-ACP patients did not have a statistically significant lower incidence of TND, Dr. Tong and coauthors noted the shorter time on ventilation and significantly lower tracheostomy rates for the b-ACP patients, 3.7% vs. 16.9% for the u-ACP group (P = .003). “In our institute, protocols to wean patients from ventilation were normally initiated as soon as consciousness was regained,” Dr. Tong and coauthors wrote.

Among the study limits Dr. Tong and coauthors acknowledged were its retrospective, nonrandomized, single-center nature, and the fact that the surgeries were performed over an 8-year period representing different eras.

The investigators reported having no relevant financial disclosures.