Objective: Antegrade cerebral perfusion has proved to be a reliable method of brain protection during surgery of thoracic aneurysms. In addition, the drawbacks of deep hypothermia may be avoided. This study examines the outcome after surgery for acute type A aortic dissections (AAD) using moderate (30 °C) systemic hypothermia compared with conventional techniques of cerebral protection. Methods: Between January 1999 and August 2003, 74 patients underwent repair of acute type A aortic dissection. Moderate systemic hypothermia (30 °C) with selective antegrade cerebral perfusion through subclavian artery (group A) was used in 18 patients. Deep hypothermia (20 - 24 °C) was employed using either retrograde (18 patients, group B) or antegrade (38 patients, group C) cerebral perfusion. Tube graft replacement was performed in 55, valve-sparing procedure in 8, and composite graft replacement in 11 patients. Results: The 30-day mortality was 5.5 % in group A, 5.5 % in group B, and 15.8 % in group C (A vs. C and B vs. C; p < 0.01). New postoperative permanent neurologic deficit occurred in 5.5 % of patients in group A, 16.7 % in group B, and 13.2 % in group C. Mean chest tube drainage within the first 24 h in groups A, B and C was 703 ± 338, 1178 ± 820, and 1447 ± 802 ml, respectively (A vs. B and A vs. C; p < 0.01). Cardiopulmonary bypass, ICU, and hospital times were significantly shorter in group A. Conclusions: Selective antegrade cerebral perfusion with moderate systemic hypothermia appears to be a safe and sufficient tool for brain protection during AAD repair. In avoiding deep hypothermia, this technique may help to reduce cardiopulmonary bypass time and hypothermia-related side effects.

OBJECTIVE: Surgery for acute type A aortic dissection remains a surgical challenge because of prolonged operative times, bleeding complications, and a considerable risk of neurological morbidity and mortality. The following study investigates the clinical results after surgical treatment for acute type A aortic dissection using selective antegrade cerebral perfusion and moderate-to-mild systemic hypothermia (≥28 °C). METHODS: Between January 2000 and January 2015, 453 consecutive patients underwent surgical treatment for acute type A aortic dissection at two aortic referral centres in Germany. Patient mean age was 67 ± 13 years, 298 patients (66%) were male. Selective unilateral or bilateral cerebral perfusion under moderate-to-mild systemic hypothermia was used in all patients. Ascending aortic replacement, hemiarch replacement and total arch replacement was performed in 9 patients (2%), 342 patients (75%) and 102 patients (23%), respectively. Clinical data were prospectively entered into the institutional databases. Mean late follow-up was 6 ± 3 years and was 98% complete. RESULTS: Cardiopulmonary bypass time totalled 181 ± 68 min and the myocardial ischaemic time 107 ± 43 min. Mean duration of selective antegrade cerebral was 46 ± 23 min. Mean lowest core temperature amounted to 28.8 ± 0.6 °C. Unilateral cerebral perfusion was performed in 298 patients (66%) and bilateral in 155 patients (34%). Mean intensive care unit stay was 5 ± 7 days. We observed new postoperative permanent neurological deficits in 27 patients (6%) and transient neurological deficits in 31 patients (7%). Thirty-day mortality was 7% (n = 32). Overall survival rate at 5 years was 77 ± 6%. CONCLUSIONS: Our data suggest that selective antegrade cerebral perfusion in combination with moderate-to-mild systemic hypothermia (≥28 °C) can be safely and reproducibly applied to surgery for acute type A aortic dissection and offers sufficient neurological and visceral organ protection.

The purpose of the present study was to determine for the first time the qualitative and quantitative impact of varying degrees of interatrial shunting on right heart dynamics and systemic perfusion in subjects with chronic pulmonary hypertension (CPH). Eight dogs underwent 3 mo of progressive pulmonary artery banding, following which right atrial and ventricular end-systolic and end-diastolic pressure-volume relations were calculated using conductance catheters. An 8-mm shunt prosthesis was inserted between the superior vena cava and left atrium, yielding a controlled model of atrial septostomy. Data were obtained 1) preshunt or “CPH”; 2) “Low-Flow” shunt; and 3) “High-Flow” shunt (occluding superior vena cava forcing all flow through the shunt). With progressive shunting, right ventricular pressure fell from 72 ± 19 mmHg (CPH) to 54 ± 17 mmHg (Low-Flow) and 47 ± 17 mmHg (High-Flow) ( P < 0.001). Cardiac output increased from 1.5 ± 0.3 l/min at CPH to 1.8 ± 0.4 l/min at Low-Flow (286 ± 105 ml/min, 15% of cardiac output; P < 0.001), but returned to 1.6 ± 0.3 l/min at High-Flow (466 ± 172 ml/min, 29% of cardiac output; P = 0.008 vs. Low-Flow, P = 0.21 vs. CPH). There was a modest rise in systemic oxygen delivery from 252 ± 46 ml/min at CPH to 276 ± 50 ml/min at Low-Flow ( P = 0.07), but substantial fall to 222 ± 50 ml/min at High-Flow ( P = 0.005 vs. CPH, P < 0.001 vs. Low-Flow). With progressive shunting, bichamber contractility did not change ( P = 0.98), but the slope of the right atrial end-diastolic pressure volume relation decreased ( P < 0.04), consistent with improved compliance. This study demonstrated that Low-Flow interatrial shunting consistently improved right atrial mechanics and systemic perfusion in subjects with CPH, while High-Flow exceeded an “ideal shunt fraction”.

Objectives The optimal hypothermic level during circulatory arrest in aortic arch surgery remains controversial, particularly in frozen elephant trunk (FET) procedures. We describe herein our experience for total arch replacement with FET technique under moderate systemic hypothermic circulatory arrest (≥ 28°C) during selective antegrade cerebral perfusion. Methods Between January 2009 and January 2016, 38 consecutive patients underwent elective total arch replacement for various aortic arch pathologies with FET technique using the E-vita Open hybrid prosthesis (Jotec GmbH, Hechingen, Germany). Selective unilateral or bilateral cerebral perfusion under moderate systemic hypothermic circulatory arrest (28.7°C ± 0.5°C) was used in all patients. Minimally invasive total arch replacement with FET via partial upper sternotomy was performed in 15 patients (39%) and in the remaining 23 patients (61%) via full sternotomy. Mean late follow-up was 3 ± 2 years and was 98% complete. Clinical data were prospectively entered into our institutional database. Results Cardiopulmonary bypass time accounted for 198 ± 58 minutes and the myocardial ischemic time 109 ± 29 minutes. Selective antegrade cerebral perfusion time was 55 ± 6 minutes. Lower body circulatory arrest time was 39 ± 11 minutes. Unilateral cerebral perfusion was performed in 31 patients (82%), and bilateral in 7 patients (18%). Intensive care unit stay was 4 ± 3 days. Thirty-day mortality was 5% (n = 2). Late survival at 3 years was 87 ± 3%. Two patients (5%) required reexploration for bleeding. Patients were discharged after a hospital length of stay of 7 ± 2 days. Postoperative permanent neurologic complication occurred in two patients (5%). Three patients (8%) experienced a transient neurologic disorder. New transient renal replacement therapy was necessary in three patients (8%). No spinal cord injury was noted. Conclusions Our data suggest that moderate systemic hypothermic circulatory arrest (≥ 28°C) in combination with antegrade cerebral perfusion can safely be applied for total aortic arch replacement with FET and offers sufficient neurologic and visceral organ protection.