Assessment of Cerebral Blood Flow With Transcranial Doppler in Right Brachial Artery Perfusion Patients

Hypothermic Circulatory Arrest in Adult Aortic Arch Surgery: A Review of Hypothermic Circulatory Arrest and its Anesthetic Implications

Diseases affecting the aortic arch often require surgical intervention. Hypothermic circulatory arrest (HCA) enables a safe approach during open aortic arch surgeries. Additionally, HCA provides neuroprotection by reducing cerebral metabolism and oxygen requirements. However, HCA comes with significant risks (eg, neurologic dysfunction, stroke, and coagulopathy), and the cardiac anesthesiologist must completely understand the surgical techniques, possible complications, and management strategies.

Neuroprotective Strategies in Repair and Replacement of the Aortic Arch

Aortic arch surgery is a technical challenge, and cerebral protection during distal anastomosis is a continued topic of controversy and discussion. The physiologic effects of hypothermic arrest and adjunctive cerebral perfusion have yet to be fully defined, and the optimal strategies are still undetermined. This review highlights the historical context, physiological rationale, and clinical efficacy of various neuroprotective strategies during arch operations.

The neurologic protection of unilateral versus bilateral antegrade cerebral perfusion in aortic arch surgery with deep hypothermic circulatory arrest: A study of 77 cases

BACKGROUD

Unilateral and bilateral antegrade cerebral perfusions (ACP) are recognized methods of cerebral protection in aortic arch surgery. However, the adequacy of cerebral protection in aortic arch surgery with deep hypothermic circulatory arrest is controversial. In this study, we compared unilateral and bilateral ACP of cerebral protection in aortic arch surgery by assessing the patient's intraoperative and postoperative brain function.

METHODS

A total of 77 patients undergoing aortic arch surgery were included in this study. Unilateral ACP was performed using a cannula in the innominate artery (n = 40), whereas bilateral ACP was conducted using an additional cannula in the left carotid artery (n = 37). Levels of S-100β and neuron specific enolase (NSE) were assayed at the beginning of cardiopulmonary bypass (T1), the beginning of circulatory arrest (T2), and post ACP at T = 25 min (T3), the end of ACP (T4), the end of cardiopulmonary bypass (T5), and at T = 1 h (T6), T = 6 h (T7), and T = 24 h (T8). Transcranial Doppler ultrasonography was used both preoperatively and intraoperatively to detect the blood flow of bilateral middle cerebral artery (MCA), and neurologic deficit incidence and mortality rates were obtained.

RESULTS

At time points T1, T2, and T3, plasma levels of S-100β and NSE were not statistically different between groups. However, S-100β and NSE levels for each time point ranging from T = T4 to T = T8 did show statistically significant differences between groups. Patients who with one side of the middle cerebral artery stenosis, used bilateral antegrade cerebral perfusions method, intraoperative Transcranial Doppler ultrasonography examination showed narrow side blood flow weaker than the normal side during the deep hypothermic circulatory arrest (DHCA), however no significant differences could be observed between the two sides (P > 0.05). The incidence of neurological dysfunction was higher in the unilateral ACP group compared to the bilateral ACP group (25% vs. 8.11%, respectively, P = 0.028). Moreover, no marked differences were observed in mortality (2.5% vs. 5.41%, respectively, P = 1.000).

CONCLUSIONS

When the duration of DHCA was 25 min or less, no significant differences were observed between unilateral and bilateral ACP. However, when DHCA exceeded 25 min, bilateral ACP was more effective compared to unilateral ACP. Due to the high variations in circle of Willis as well as increased safety, simplicity, and efficiency, the bilateral ACP approach is preferred over the unilateral technique.

Serial monitoring of CO2 reactivity following sport concussion using hypocapnia and hypercapnia

PRIMARY OBJECTIVE

This study examined the effects of mild traumatic brain injury (mTBI) on cerebrovascular reactivity (CVR).

RESEARCH DESIGN

A repeated measures design was used to examine serial changes in CVR.

METHODS AND PROCEDURES

Twenty subjects who recently suffered a mTBI were subjected to a respiratory challenge consisting of repeated 20 s breath-holds (BH) and hyperventilations (HV). Testing occurred on days 2 (D2), 4 (D4) and 8 (D8) post-injury as well as a baseline (BASE) assessment (after return-to-play). Transcranial Doppler was used to assess mean cerebral blood velocity (vMCA) and expired gas analysis provided end-tidal carbon dioxide (PETCO2) levels.

RESULTS

There was no significant difference in resting vMCA across all testing days for mTBI. No significant differences in PETCO2 were found throughout the testing protocol. A significant effect (p < 0.001) of testing day on vMCA was found during BH and HV challenges for mTBI. Post-hoc analysis revealed significant differences (p < 0.05) in vMCA between D2 and the other testing days.

CONCLUSIONS

These data suggest that, following mTBI: (1) CVR is not impaired at rest; (2) CVR is impaired in response to respiratory stress; and (3) the impairment may be resolved as early as 4 days post-injury.

Advantages of upper brachial artery cannulation in aortic surgery

BACKGROUND

The best method of cerebral protection during aortic arch surgery remains controversial. However, antegrade cerebral perfusion seems to be the most favorable because of better neurological outcomes. Although there have been many studies on antegrade cerebral perfusion via upper brachial cannulation, there is a lack of studies focusing particularly on local complications, with objective findings. The aim of this study was to investigate the local neurological and vascular complications following upper brachial cannulation.

METHODS AND RESULTS

This study included 44 patients who underwent procedures on the ascending aorta, aortic arch, or descending aorta with upper brachial artery cannulation for cardiopulmonary bypass at OSM Ortadogu Hospital and Cankaya Hospital between January 2009 and April 2012. The mean age of the 32 (72.7%) men and 12 (27.3%) women was 55.2 ± 12.3 years. Doppler analysis of the upper brachial artery was performed in 26 (59%) patients. Mean follow-up time for Doppler analysis was 5.7 ± 2 months. The mean antegrade cerebral perfusion time was 35 ± 16.1 min. The mean degree of hypothermia was 25.1 ± 2.0 . Hospital death occurred in 4 (9.1%) patients, and 2 (4.5%) suffered local neurologic complications. Electromyelography analysis was carried out in the 2 patients who suffered local neurologic symptoms.

CONCLUSIONS

Brachial artery cannulation is technically simple and less time consuming, thus suitable even for emergency cases. With an acceptable risk of local complications, we recommend routine use of upper brachial cannulation for antegrade cerebral perfusion.

Selective cerebral perfusion with 4-branch graft total aortic arch replacement: outcomes in 12 patients

Background

Aortic arch reconstruction is associated with high neurological morbidity. Our purpose is to describe our experience using a 4-branched graft and selective antegrade brain perfusion (SABP) for total aortic arch replacement (TAR).

Methods

We retrospectively reviewed the medical records of 12 patients who received TAR, with or without ascending aorta replacement, with a 4-branched graft for Stanford type A dissection (n = 9) or aortic arch aneurysm (n = 3). In all patients surgery was performed with deep hypothermic circulatory arrest (DHCA) with or without retrograde brain perfusion, and selective antegrade brain perfusion (SABP) via the subclavian artery or axillary artery.

Results

There were 8 males and 4 females with an average age of 63.14 years. Emergent operations were performed in 9 patients with acute type A aortic dissections. Of all 12 patients, 2 deaths occurred and 1 patient experienced lower extremity paraplegia resulting in an in-hospital mortality rate of 16.6% and a permanent neurological deficit rate of 8.3%.

Conclusions

The use of a 4-branched graft, hypothermic circulatory arrest, and SABP is a useful operative method for aortic arch replacement with acceptable morbidity and mortality.

Results with a selective revascularization strategy for left subclavian artery coverage during thoracic endovascular aortic repair

BACKGROUND

The need for routine left subclavian artery (LSCA) revascularization when this vessel is covered during thoracic endovascular aortic repair remains controversial. We report our results with a selective LSCA revascularization strategy during thoracic endovascular aortic repair.

METHODS

Between May 2002 and March 2010, 287 thoracic endovascular aortic repair procedures were performed at our institution. LSCA coverage occurred in 145 (51%), which form the basis of this report.

RESULTS

Left subclavian artery revascularization was performed in 32 patients (22%) through a left common carotid-LSCA bypass. Indications for selective LSCA revascularization included spinal cord protection in 10, patent pedicled left internal mammary artery graft in 9, left arm ischemia after LSCA coverage in 5, origin of the left vertebral artery from the arch in 4, dialysis access in the left arm in 2, and vertebrobasilar insufficiency in 2. There were no instances of dominant left vertebral artery. The revascularized and non-revascularized groups had similar rates of death (6.3% vs 1.8%; p=0.21), stroke (3.1% vs 3.5%; p>0.99), permanent paraplegia or paraparesis (3.1% vs 0%; p=0.22), and type II endoleak (4.3% vs 6.5%; p>0.99). There were no instances of ischemic stroke related to left posterior circulation hypoperfusion. Four complications of carotid-subclavian bypass occurred in 3 patients (9.4%).

CONCLUSIONS

Selective LSCA revascularization is safe and does not appear to increase the risk of neurologic events. Further, subclavian revascularization is not without complications, which should be considered with regards to a nonselective revascularization strategy.

Central Nervous System Protection in Cardiac Surgery

Neurological dysfunction and stroke following cardiac surgery and thoracic surgery requiring hypothermic circulatory arrest is a well-defined problem. The original studies in CABG patients identified risk factors, such as prior stroke and lower educational level. There is older evidence suggesting that higher perfusion pressures during cardiopulmonary bypass are helpful. Hyperthermia during rewarming on cardiopulmonary bypass and postoperative hyperthermia have been associated with adverse cognitive outcomes. Glucose management intraoperatively remains controversial, but most now advocate for moderate glucose control using insulin, if required. The subset of patients having thoracic aortic surgery requiring periods of aortic discontinuity are particularly problematic. A cerebral protection strategy should be determined, and this may include hypothermic circulatory arrest, selective cerebral perfusion, or retrograde cerebral perfusion. All of these techniques have been associated with good surgical outcomes, but there is little information on cognitive outcomes of thoracic aortic surgery.

Neurochemical markers during selective cerebral perfusion via the right brachial artery

Unilateral selective cerebral perfusion through right brachial artery is one of the cerebral protection methods for aortic arch repair. The purpose of this study is to determine whether cerebral perfusion through contra-lateral hemisphere is adequate or not. Seventeen consecutive patients underwent aortic arch repair using low flow antegrade selective cerebral perfusion (ASCP) through right brachial artery under moderate hypothermia. We measured S100beta and neuron-specific enolase (NSE) levels, venous O(2) saturation, lactate, and glucose from both left and right jugular vein blood samples before, during and following ASCP and cardiopulmonary bypass. There was no operative mortality or neurological complication in these patients. No significant differences were observed in S100beta and NSE levels, venous saturation, glucose and lactate between the blood samples which were gathered from both jugular veins, statistically. This technique, as far as biochemical markers are concerned, seems to provide adequate perfusion for both right and left cerebral hemispheres.

Unilateral brachial artery antegrade selective cerebral perfusion following carotid endarterectomy for carotid, coronary, and aortic aneurysmal surgery

In the presence of multiple concomitant occlusive and aneurysmal diseases, selection of the brain protection method is a primary concern. A case with a disease triad of stenotic lesions in internal carotid arteries, coronary artery atherosclerosis, and an ascending-arcus aorta aneurysm is presented. We simultaneously performed right carotid endarterectomy, coronary artery bypass grafting, and graft replacement of the ascending-arcus aorta. Brain protection was achieved with continuous right brachial artery antegrade selective cerebral perfusion under moderate hypothermia, following carotid endarterectomy. The operative technique is detailed and antegrade selective cerebral perfusion following the carotid endarterectomy for aneurysmal surgery is discussed.

Aortic Arch Replacement With a Trifurcated Graft

BACKGROUND

The purpose of this study was to review the results of aortic arch replacement using a trifurcated arch graft in conjunction with hypothermic circulatory arrest (HCA) and selective antegrade cerebral perfusion (SCP).

METHODS

One hundred fifty consecutive patients (91 male; mean age, 63 +/- 14 years; range, 20 to 87) had aortic arch replacement using a trifurcated arch graft and HCA/SCP from September 1999 to December 2005. The axillary artery was used for cannulation; a trifurcated graft was sewn to the arch vessels during a short interval of HCA; SCP was utilized through the trifurcation graft during the proximal and distal arch repair, and then the trifurcation graft was sewn to the arch graft. Fifty-five patients had chronic dissection; 48 had atherosclerotic and 29 had degenerative aneurysms; 74 had undergone previous cardiac surgery. Isolated arch reconstruction was undertaken in 38 patients: concomitant procedures included ascending aortic replacement in 74; ascending aorta and root replacement in 21; descending replacement in 4, and coronary artery bypass grafting in 36. An elephant trunk was used in 144, but distal to the left subclavian artery in only 87; in 34, it was distal to the left carotid, in 9, it was between the brachiocephalic and left carotid, and in 18, it was proximal to all arch branches. Mean HCA duration was 31.1 +/- 6.5 minutes; SCP lasted 66.6 +/- 21.0 minutes, at a mean temperature of 15.8 +/- 2.1 degrees C.

RESULTS

Adverse outcome occurred in 13 of 150 patients (8.7%): there were 7 hospital deaths and 6 permanent strokes. Temporary neurologic dysfunction was seen in only 7 patients, and renal failure was transient in 9 patients requiring dialysis.

CONCLUSIONS

The use of a trifurcated arch graft with HCA and SCP is a safe and versatile technique for repair of arch aneurysms.

Carotid artery cannulation in aortic surgery

OBJECTIVE

Carotid artery cannulation was initially established at our clinic for surgery of acute aortic dissection, and it became the standard approach for procedures in which circulatory arrest is necessary. The aim of the study was to evaluate this method's efficiency regarding postoperative outcomes after the first 100 procedures.

METHODS

Between July 2002 and October 2005, 100 patients underwent aortic surgery using carotid artery cannulation by a side graft for arterial return with a mean flow rate of 4.6 +/- 0.5 L/min. There were 27 patients with acute and 2 with chronic type A aortic dissection. Sixteen patients had had prior cardiac surgery. During circulatory arrest, the arterial line was used for unilateral cerebral perfusion in moderate hypothermia (mean rectal temperature 28 degrees C +/- 1.6 degrees C) with a mean flow rate of 0.85 +/- 0.2 L/min.

RESULTS

Carotid artery cannulation offered adequate arterial return in all patients. In no case was a switch to another cannulation site necessary for arterial return. Furthermore, no complications related to the cannulation site were observed. One patient with acute dissection and 1 with chronic aneurysm died during the early postoperative course. Thus, 30-day mortality was 2.0% for the whole group and 3.7% for the dissection group. Two patients with severe calcification of the aortic valve had strokes. There were no strokes in the dissection group, although there were preoperative signs of cerebral malperfusion in 4 patients.

CONCLUSIONS

Carotid artery cannulation is a fast, safe, and efficient method of arterial cannulation even in very obese patients. In addition, it simplifies the procedure of unilateral cerebral perfusion through the arterial line during circulatory arrest, making it completely unnecessary to interrupt cerebral perfusion.

Whole-Body Perfusion under Moderate-Degree Hypothermia during Aortic Arch Repair

INTRODUCTION

There continue to be some controversies concerning aortic arch reconstruction, especially the cerebral protection methods. We report our operative and postoperative outcomes for cases of aortic arch replacement using whole-body perfusion during aortic reconstruction under 28 degrees C moderate hypothermia.

MATERIALS AND METHODS

A total of 12 patients were operated on between March 2003 and November 2005. Two of the patients were female. The mean age of the patients was 53.5 x 7.3 years (range, 42-65 years). We cannulated the right axillary artery for cerebral perfusion and the right femoral artery for body perfusion. Arch replacement was done under continuous antegrade cerebral perfusion through the right axillary artery and continuous body perfusion through the right femoral artery via intra-aortic occlusion of the proximal descending aorta with an intra-aortic occlusion catheter. Perioperative data and postoperative outcomes, blood urea nitrogen, serum creatinine, and alanin aminotransferase values were evaluated retrospectively in the patients.

RESULTS

There was only 1 hospital mortality. There were no neurologic complications. Postoperative levels of blood urea nitrogen and creatinin did not show significant difference but the alanin aminotransferase levels were significantly higher in the postoperative period, which was within the normal ranges of cardiopulmonary bypass effect.

DISCUSSION

Whole-body perfusion through the axillary and femoral arteries may provide more time for the surgeon and good cerebral and visceral protection, which are especially important for surgical teams in the learning curve.

Antegrade Cerebral Perfusion With a Simplified Technique: Unilateral Versus Bilateral Perfusion

BACKGROUND

Selective antegrade cerebral perfusion has been introduced as a strategy of cerebral protection in operations on the aortic arch with hypothermic circulatory arrest. Several techniques of unilateral and bilateral cerebral perfusion have been described with varying results.

METHODS

Patients underwent either unilateral cerebral perfusion with a cannula in the right subclavian artery or bilateral cerebral perfusion, with an additional cannula in the left carotid artery. A simplified Seldinger-type technique for subclavian artery cannulation was employed. Results were analyzed with multivariable logistic regression analysis and propensity score analysis to adjust for nonrandomized treatment assignment.

RESULTS

Of 65 patients, 17 (26%) had unilateral cerebral perfusion. Mortality was 11% (n = 7); 14% (n = 9) had a stroke. In multivariable analysis, unilateral cerebral perfusion was significantly associated with stroke (odds ratio 6.6 [1.2 to 36]). Age more than 70 years was associated with in-hospital death (odds ratio 12 [1.3 to 113]), and concomitant coronary artery bypass graft surgery was associated with adverse outcome (odds ratio 23 [1.8 to 299]). Balancing variables in a propensity score analysis, stroke remained significantly more common with unilateral brain perfusion (29% versus 0%, p = 0.045). Complications associated with subclavian artery cannulation were encountered in 1 patient (1.5%).

CONCLUSIONS

The described cannulation technique is safe and effective. Bilateral cerebral perfusion is easily achieved and is associated with decreased stroke risk, and should be the preferred brain protection strategy.

Methods of cerebral protection in surgery of the thoracic aorta

During the last decade, a considerable increase in the number of operations on the thoracic aorta has been observed. Although patient's outcomes have improved considerably, this surgery is still associated with significant morbidity and mortality due to neurological complications. Various methods have been proposed and widely used as means to protect the brain from ischemic damage. This review summarizes the principal methods of cerebral protection, describes the advantages and disadvantages of each method and their impact on patient outcomes, and discusses the different surgical techniques proposed to minimize the risk of cerebral injuries.