As originally published in 1993: Brain protection via cerebral retrograde perfusion during aortic arch aneurysm repair. Updated in 2001

Deep hypothermic circulatory arrest

Effective cerebral protection remains the principle concern during aortic arch surgery. Hypothermic circulatory arrest (HCA) is entrenched as the primary neuroprotection mechanism since the 70s, as it slows injury-inducing pathways by limiting cerebral metabolism. However, increases in HCA duration has been associated with poorer neurological outcomes, necessitating the adjunctive use of antegrade (ACP) and retrograde cerebral perfusion (RCP). ACP has superseded RCP as the preferred perfusion strategy as it most closely mimic physiological perfusion, although there exists uncertainty regarding several technical details, such as unilateral versus bilateral perfusion, flow rate and temperature, perfusion site, undue trauma to head vessels, and risks of embolization. Nevertheless, we believe that the convenience, simplicity and effectiveness of straight DHCA justifies its use in the majority of elective and emergency cases. The following perspective offers a historical and clinical comparison of the DHCA with other techniques of cerebral protection.

Importance of blood pressure control after repair of acute type a aortic dissection: 25-year follow-up in 252 patients

The purpose of this study was to evaluate factors that impact outcome following repair of type A aortic dissection. Over 25 years (1984-2009), 252 patients underwent repair of acute type A dissection. Mean follow-up for reoperation or death was 6.9±5.9 years. Operative mortality was 16% (41 of 252). Multivariate analysis identified one risk factor for operative death: presentation malperfusion (P=.003). For operative survivors, 5-, 10-, and 20-year survival was 78%±3%, 59%±4%, and 24%±6%, respectively. Late death occurred earlier in patients with previous stroke (P=.02) and chronic renal insufficiency (P=.007). Risk factors for late reoperation included male sex (P=.006), Marfan syndrome (P<.001), elevated systolic blood pressure (SBP, P<.001), and absence of β-blocker therapy (P<.001). Kaplan-Meier analysis demonstrated at 10-year follow-up that patients who maintained SBP <120 mm Hg had improved freedom from reoperation (92±5%) compared with those with SBP 120 mm Hg to 140 mm Hg (74%±7%) or >140 mm Hg (49%±14%, P<.001). At 10-year follow-up, patients on β-blocker therapy experienced 86%±5% freedom from reoperation compared with only 57%±11% for those without (P<.001). Operative survival was decreased with preoperative malperfusion. Long-term survival was dependent on comorbidities but not operative approach. Reoperation was markedly increased in patients not on β-blocker therapy and decreased with improved SBP control. Strict control of hypertension with β-blocker therapy is warranted following repair of acute type A dissection.

Impact of Perfusion Strategy on Neurologic Recovery in Acute Type A Aortic Dissection

BACKGROUND

The optimal perfusion strategy during surgery of acute type A aortic dissection is controversial. The purpose of this study was to determine the impact of retrograde cerebral perfusion during hypothermic circulatory arrest on short-term and long-term outcome in this specific patient population.

METHODS

Between 1984 and 2005, 175 consecutive patients underwent repair of an acute type A dissection. Three different surgical approaches were used: aortic cross-clamping without hypothermic circulatory arrest in 50 (29%), hypothermic circulatory arrest alone in 69 (39%), and hypothermic circulatory arrest with supplemental retrograde cerebral perfusion in 56 (32%).

RESULTS

Operative mortality was 18% +/- 3% (+/- 70% confidence interval), and adverse outcomes (death or cerebrovascular accident) occurred in 21% +/- 3% of patients (p = 0.97 between groups). Multivariate analysis identified valve replacement (p = 0.04), preoperative flow complications (p = 0.03), and non-Marfan syndrome (p = 0.04) as predictors of operative mortality. Intraoperative dissection (p < 0.001) and history of cerebrovascular disease (p = 0.02) were predictors for permanent neurologic deficit, and retrograde cerebral perfusion was shown to have a protective effect on transient neurologic deficits (p = 0.008). Kaplan-Meier survival was 75% +/- 3% at 1 year (131 patients at risk), 63% +/- 4% at 5 years (87 patients at risk), and 49% +/- 4% at 10 years (48 patients at risk) and was independent of surgical approach (p = 0.37). Long-term survival was diminished with increased age (p < 0.001), earlier operative year (p < 0.001), and coronary artery disease (p = 0.02).

CONCLUSIONS

The current investigation suggests improved neurologic recovery with circulatory arrest and supplemental retrograde cerebral perfusion. Operative mortality and long-term survival were comparable among groups.

Perioperative stroke: evaluation, management, and possible preventive measures

Mechanisms of perioperative ischemic stroke include: hypotension, hypercoagulability, arrhythmias with embolism, or direct vascular insult. Mechanisms of perioperative hemorrhagic stroke include: use of antithrombotics, hypertension, or direct vascular insult.

Influence of retrograde cerebral perfusion during aortic arch procedures

BACKGROUND

Recent reports suggest dramatic improvement in outcome using retrograde cerebral perfusion (RCP) during operations on the arch; however, most investigators have compared contemporary results with historic controls. The purpose of this study was to determine the impact of RCP within the same patient population and time period.

METHODS

From 1996 to 2000, 72 consecutive patients underwent an aortic arch procedure using hypothermic circulatory arrest (HCA) (31 acute dissection or rupture, 41 chronic dissection or aneurysm). Supplemental RCP was used in 36 patients, whereas 36 patients had HCA alone. The groups were similar in age, emergent status, and cardiopulmonary bypass time (p > 0.08), but HCA time was higher with RCP (40 +/- 15 minutes versus 29 +/- 14 minutes; p < 0.001).

RESULTS

Operative mortality was 10% +/- 4% (+/- 70% confidence limit), and adverse outcomes (death or cerebrovascular accident) occurred in 14% +/- 4%, but there was no difference between HCA alone (8% +/- 5%, 14% +/- 6%) and HCA with RCP (11% +/- 5%, 14% +/- 6%) (p > 0.73). The incidence of transient neurologic dysfunction was also similar (HCA alone, 11% +/- 5%; HCA with RCP, 17% +/- 6%; p > 0.73). Multivariate risk factors for mortality included emergency operation and HCA time (p < 0.02). Risk factors for adverse outcome included emergency operation and atheromatous ascending aorta (p < 0.03). Risk factors for transient neurologic dysfunction included preexisting cerebrovascular disease and rewarming retrograde (femoral) rather than antegrade (through the graft) (p < 0.03).

CONCLUSIONS

Supplemental RCP during HCA did not decrease mortality or neurologic complications. Retrograde rewarming through the femoral artery after completion of the distal anastomosis increased transient neurologic dysfunction. Therefore, RCP remains optional, but reperfusion should be antegrade to improve neurologic recovery.