Femoral arterial cannulation for surgical repair of stanford type A aortic dissection.

BACKGROUND: The benefits and harms associated with femoral artery cannulation over other sites of arterial cannulation for surgical repair of acute Stanford type A aortic dissection (TAAD) are not conclusively established. METHODS: We evaluated the outcomes after surgery for TAAD using femoral artery cannulation, supra-aortic arterial cannulation (i.e., innominate/subclavian/axillary artery cannulation), and direct aortic cannulation. RESULTS: 3751 (96.1%) patients were eligible for this analysis. In-hospital mortality using supra-aortic arterial cannulation was comparable to femoral artery cannulation (17.8% vs. 18.4%; adjusted OR 0.846, 95% CI 0.799-1.202). This finding was confirmed in 1028 propensity score-matched pairs of patients with supra-aortic arterial cannulation or femoral artery cannulation (17.5% vs. 17.0%, p = 0.770). In-hospital mortality after direct aortic cannulation was lower compared to femoral artery cannulation (14.0% vs. 18.4%, adjusted OR 0.703, 95% CI 0.529-0.934). Among 583 propensity score-matched pairs of patients, direct aortic cannulation was associated with lower rates of in-hospital mortality (13.4% vs. 19.6%, p = 0.004) compared to femoral artery cannulation. Switching of the primary site of arterial cannulation was associated with increased rate of in-hospital mortality (36.5% vs. 17.0%; adjusted OR 2.730, 95% CI 1.564-4.765). Ten-year mortality was similar in the study cohorts. CONCLUSIONS: In this study, the outcomes of surgery for TAAD using femoral arterial cannulation were comparable to those using supra-aortic arterial cannulation. However, femoral arterial cannulation was associated with higher in-hospital mortality than direct aortic cannulation. TRIAL REGISTRATION: ClinicalTrials.gov registration code: NCT04831073.

Classification of the Urgency of the Procedure and Outcome of Acute Type A Aortic Dissection.

Surgery for type A aortic dissection (TAAD) is associated with a high risk of early mortality. The prognostic impact of a new classification of the urgency of the procedure was evaluated in this multicenter cohort study. Data on consecutive patients who underwent surgery for acute TAAD were retrospectively collected in the multicenter, retrospective European Registry of TAAD (ERTAAD). The rates of in-hospital mortality of 3,902 consecutive patients increased along with the ERTAAD procedure urgency grades: urgent procedure 10.0%, emergency procedure grade 1 13.3%, emergency procedure grade 2 22.1%, salvage procedure grade 1 45.6%, and salvage procedure grade 2 57.1% (p <0.0001). Preoperative arterial lactate correlated with the urgency grades. Inclusion of the ERTAAD procedure urgency classification significantly improved the area under the receiver operating characteristics curves of the regression model and the integrated discrimination indexes and the net reclassification indexes. The risk of postoperative stroke/global brain ischemia, mesenteric ischemia, lower limb ischemia, dialysis, and acute heart failure increased along with the urgency grades. In conclusion, the urgency of surgical repair of acute TAAD, which seems to have a significant impact on the risk of in-hospital mortality, may be useful to improve the stratification of the operative risk of these critically ill patients. This study showed that salvage surgery for TAAD is justified because half of the patients may survive to discharge.

Preoperative arterial lactate and outcome after surgery for type A aortic dissection: The ERTAAD multicenter study.

Background: Acute type A aortic dissection (TAAD) is associated with significant mortality and morbidity. In this study we evaluated the prognostic significance of preoperative arterial lactate concentration on the outcome after surgery for TAAD. Methods: The ERTAAD registry included consecutive patients who underwent surgery for acute type A aortic dissection (TAAD) at 18 European centers of cardiac surgery. Results: Data on arterial lactate concentration immediately before surgery were available in 2798 (71.7 %) patients. Preoperative concentration of arterial lactate was an independent predictor of in-hospital mortality (mean, 3.5 ± 3.2 vs 2.1 ± 1.8 mmol/L, adjusted OR 1.181, 95%CI 1.129-1.235). The best cutoff value preoperative arterial lactate concentration was 1.8 mmol/L (in-hospital mortality, 12.0 %, vs. 26.6 %, p < 0.0001). The rates of in-hospital mortality increased along increasing quintiles of arterial lactate and it was 12.1 % in the lowest quintile and 33.6 % in the highest quintile (p < 0.0001). The difference between multivariable models with and without preoperative arterial lactate was statistically significant (p = 0.0002). The NRI was 0.296 (95%CI 0.200-0.391) (p < 0.0001) with -17 % of events correctly reclassified (p = 0.0002) and 46 % of non-events correctly reclassified (p < 0.0001). The IDI was 0.025 (95%CI 0.016-0.034) (p < 0.0001). Six studies from a systematic review plus the present one provided data for a pooled analysis which showed that the mean difference of preoperative arterial lactate between 30-day/in-hospital deaths and survivors was 1.85 mmol/L (95%CI 1.22-2.47, p < 0.0001, I2 64 %). Conclusions: Hyperlactatemia significantly increased the risk of mortality after surgery for acute TAAD and should be considered in the clinical assessment of these critically ill patients.

Remote ischemic preconditioning and hypoxia-induced biomarkers in acute myocardial infarction: study on a porcine model.

Objectives. Remote ischemic preconditioning (RIPC) mitigates acute myocardial infarction (AMI). We hypothesized that RIPC reduces the size and severity of AMI and explored molecular mechanisms behind this phenomenon. Design. In two series of experiments, piglets underwent 60 min of the circumflex coronary artery occlusion, resulting in AMI. Piglets were randomly assigned into the RIPC groups (n = 7 + 7) and the control groups (n = 7 + 7). The RIPC groups underwent four 5-min hind limb ischemia-reperfusion cycles before AMI. In series I, the protective efficacy of RIPC was investigated by using biomarkers and echocardiography with a follow-up of 24 h. In series II, the heart of each piglet was harvested for TTC-staining to measure infarct size. Muscle biopsies were collected from the hind limb to explore molecular mechanisms of RIPC using qPCR and Western blot analysis. Results. The levels of CK-MBm (p = 0.032) and TnI (p = 0.007) were lower in the RIPC group. Left ventricular ejection fraction in the RIPC group was greater at the end of the follow-up. The myocardial infarct size in the RIPC group was smaller (p = 0.033). Western blot indicated HIF1α stabilization in the skeletal muscle of the RIPC group. PCR analyses showed upregulation of the HIF target mRNAs for glucose transporter (GLUT1), glucose transporter 4 (GLUT4), phosphofructokinase 1 (PFK1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), enolase 1 (ENO1), lactate dehydrogenase (LDHA) and endothelial nitric oxidate synthase (eNOS). Conclusions. Biochemical, physiologic, and histologic evidence confirms that RIPC decreases the size of AMI. The HIF pathway is likely involved in the mechanism of the RIPC.

Direct Aortic Versus Supra-Aortic Arterial Cannulation During Surgery for Acute Type A Aortic Dissection.

AIMS: In this study we evaluated the impact of direct aortic cannulation versus innominate/subclavian/axillary artery cannulation on the outcome after surgery for type A aortic dissection. METHODS: The outcomes of patients included in a multicenter European registry (ERTAAD) who underwent surgery for acute type A aortic dissection with direct aortic cannulation versus those with innominate/subclavian/axillary artery cannulation, i.e. supra-aortic arterial cannulation, were compared using propensity score matched analysis. RESULTS: Out of 3902 consecutive patients included in the registry, 2478 (63.5%) patients were eligible for this analysis. Direct aortic cannulation was performed in 627 (25.3%) patients, while supra-aortic arterial cannulation in 1851 (74.7%) patients. Propensity score matching yielded 614 pairs of patients. Among them, patients who underwent surgery for TAAD with direct aortic cannulation had significantly decreased in-hospital mortality (12.7% vs. 18.1%, p = 0.009) compared to those who had supra-aortic arterial cannulation. Furthermore, direct aortic cannulation was associated with decreased postoperative rates of paraparesis/paraplegia (2.0 vs. 6.0%, p < 0.0001), mesenteric ischemia (1.8 vs. 5.1%, p = 0.002), sepsis (7.0 vs. 14.2%, p < 0.0001), heart failure (11.2 vs. 15.2%, p = 0.043), and major lower limb amputation (0 vs. 1.0%, p = 0.031). Direct aortic cannulation showed a trend toward decreased risk of postoperative dialysis (10.1 vs. 13.7%, p = 0.051). CONCLUSIONS: This multicenter cohort study showed that direct aortic cannulation compared to supra-aortic arterial cannulation is associated with a significant reduction of the risk of in-hospital mortality after surgery for acute type A aortic dissection. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04831073.

Impact of high-risk features on outcome of acute type B aortic dissection.

Background: Acute type B aortic dissection (TBAD) is a severe condition associated with significant morbidity and mortality. The optimal classification and treatment strategy of TBAD remain controversial and inconsistent. Methods: This analysis includes patients treated for acute TBAD at the Helsinki University Hospital, Finland between 2007 and 2019. The endpoints were early and late mortality, intervention of the aorta, and a composite of death and aortic intervention in uncomplicated patients and high-risk patients. Results: This study included 162 consecutive TBAD patients (27.8% females), 114 in the high-risk group and 48 in the uncomplicated group, with a mean age of 67.6 ± 13.9 years. Intramural hematoma was reported in 63 cases (38.9%). The mean follow-up was 5.1 ± 3.9 years. In-hospital/30-day mortality (n = 4; 3.5%) occurred solely in the high-risk group (P = .32). Additionally, TBAD-related adverse events (n = 23; 20.2%) were observed only in the high-risk group (P < .001). The cumulative incidences of the composite TBAD outcome with non-TBAD-related death as a competing risk were 6.6% (95% CI, 1.7%-16.5%) in the uncomplicated group and 29.5% (95% CI, 21.1%-38.3%) in the high-risk group at 5 years and 6.6% (95% CI, 1.7%-16.5%) and 33.0% (95% CI, 23.7%-42.6%) at 10 years (P = .001, Gray test). Extracardiac arteriopathy (subdistribution hazard ratio [SHR], 2.61; 95% CI, 1.08-6.27) and coronary artery disease (SHR, 2.24; 95% CI, 1.07-4.71) were risk factors for adverse aortic-related events in univariable competing-risk regression analysis. Conclusions: Recognition of risk factors underlying adverse events related to TBAD is essential because the disease progression impacts both early and late outcomes. Early aortic repair in high-risk TBAD may reduce long-term morbidity and mortality.

Interinstitutional analysis of the outcome after surgery for type A aortic dissection.

PURPOSE: To evaluate the impact of individual institutions on the outcome after surgery for Stanford type A aortic dissection (TAAD). METHODS: This is an observational, multicenter, retrospective cohort study including 3902 patients who underwent surgery for TAAD at 18 university and non-university hospitals. RESULTS: Logistic regression showed that four hospitals had increased risk of in-hospital mortality, while two hospitals were associated with decreased risk of in-hospital mortality. Risk-adjusted in-hospital mortality rates were lower in four hospitals and higher in other four hospitals compared to the overall in-hospital mortality rate (17.7%). Participating hospitals were classified as overperforming or underperforming if their risk-adjusted in-hospital mortality rate was lower or higher than the in-hospital mortality rate of the overall series, respectively. Propensity score matching yielded 1729 pairs of patients operated at over- or underperforming hospitals. Overperforming hospitals had a significantly lower in-hospital mortality (12.8% vs. 22.2%, p < 0.0001) along with decreased rate of stroke and/or global brain ischemia (16.5% vs. 19.9%, p = 0.009) compared to underperforming hospitals. Aggregate data meta-regression of the results of participating hospitals showed that hospital volume was inversely associated with in-hospital mortality (p = 0.043). Hospitals with an annual volume of less than 15 cases had an increased risk of in-hospital mortality (adjusted OR, 1.345, 95% CI 1.126-1.607). CONCLUSION: The present findings indicate that there are significant differences between hospitals in terms of early outcome after surgery for TAAD. Low hospital volume may be a determinant of poor outcome of TAAD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04831073.

Baseline risk factors of in-hospital mortality after surgery for acute type A aortic dissection: an ERTAAD study.

Background: Surgery for type A aortic dissection (TAAD) is associated with high risk of mortality. Current risk scoring methods have a limited predictive accuracy. Methods: Subjects were patients who underwent surgery for acute TAAD at 18 European centers of cardiac surgery from the European Registry of Type A Aortic Dissection (ERTAAD). Results: Out of 3,902 patients included in the ERTAAD, 2,477 fulfilled the inclusion criteria. In the validation dataset (2,229 patients), the rate of in-hospital mortality was 18.4%. The rate of composite outcome (in-hospital death, stroke/global ischemia, dialysis, and/or acute heart failure) was 41.2%, and 10-year mortality rate was 47.0%. Logistic regression identified the following patient-related variables associated with an increased risk of in-hospital mortality [area under the curve (AUC), 0.755, 95% confidence interval (CI), 0.729-0.780; Brier score 0.128]: age; estimated glomerular filtration rate; arterial lactate; iatrogenic dissection; left ventricular ejection fraction ≤50%; invasive mechanical ventilation; cardiopulmonary resuscitation immediately before surgery; and cerebral, mesenteric, and peripheral malperfusion. The estimated risk score was associated with an increased risk of composite outcome (AUC, 0.689, 95% CI, 0.667-0.711) and of late mortality [hazard ratio (HR), 1.035, 95% CI, 1.031-1.038; Harrell's C 0.702; Somer's D 0.403]. In the validation dataset (248 patients), the in-hospital mortality rate was 16.1%, the composite outcome rate was 41.5%, and the 10-year mortality rate was 49.1%. The estimated risk score was predictive of in-hospital mortality (AUC, 0.703, 95% CI, 0.613-0.793; Brier score 0.121; slope 0.905) and of composite outcome (AUC, 0.682, 95% CI, 0.614-0.749). The estimated risk score was predictive of late mortality (HR, 1.035, 95% CI, 1.031-1.038; Harrell's C 0.702; Somer's D 0.403), also when hospital deaths were excluded from the analysis (HR, 1.024, 95% CI, 1.018-1.031; Harrell's C 0.630; Somer's D 0.261). Conclusions: The present analysis identified several baseline clinical risk factors, along with preoperative estimated glomerular filtration rate and arterial lactate, which are predictive of in-hospital mortality and major postoperative adverse events after surgical repair of acute TAAD. These risk factors may be valuable components for risk adjustment in the evaluation of surgical and anesthesiological strategies aiming to improve the results of surgery for TAAD. Clinical Trial Registration: https://clinicaltrials.gov, identifier NCT04831073.

Outcome after Surgery for Iatrogenic Acute Type A Aortic Dissection.

(1) Background: Acute Stanford type A aortic dissection (TAAD) may complicate the outcome of cardiovascular procedures. Data on the outcome after surgery for iatrogenic acute TAAD is scarce. (2) Methods: The European Registry of Type A Aortic Dissection (ERTAAD) is a multicenter, retrospective study including patients who underwent surgery for acute TAAD at 18 hospitals from eight European countries. The primary outcomes were in-hospital mortality and 5-year mortality. Twenty-seven secondary outcomes were evaluated. (3) Results: Out of 3902 consecutive patients who underwent surgery for acute TAAD, 103 (2.6%) had iatrogenic TAAD. Cardiac surgery (37.8%) and percutaneous coronary intervention (36.9%) were the most frequent causes leading to iatrogenic TAAD, followed by diagnostic coronary angiography (13.6%), transcatheter aortic valve replacement (10.7%) and peripheral endovascular procedure (1.0%). In hospital mortality was 20.5% after cardiac surgery, 31.6% after percutaneous coronary intervention, 42.9% after diagnostic coronary angiography, 45.5% after transcatheter aortic valve replacement and nihil after peripheral endovascular procedure (p = 0.092), with similar 5-year mortality between different subgroups of iatrogenic TAAD (p = 0.710). Among 102 propensity score matched pairs, in-hospital mortality was significantly higher among patients with iatrogenic TAAD (30.4% vs. 15.7%, p = 0.013) compared to those with spontaneous TAAD. This finding was likely related to higher risk of postoperative heart failure (35.3% vs. 10.8%, p < 0.0001) among iatrogenic TAAD patients. Five-year mortality was comparable between patients with iatrogenic and spontaneous TAAD (46.2% vs. 39.4%, p = 0.163). (4) Conclusions: Iatrogenic origin of acute TAAD is quite uncommon but carries a significantly increased risk of in-hospital mortality compared to spontaneous TAAD.

13-year single-center experience with the treatment of acute type B aortic dissection.

Background. Acute type B aortic dissection (TBAD) is catastrophic event associated with significant mortality and lifelong morbidity. The optimal treatment strategy of TBAD is still controversial. Methods. This analysis includes patients treated for TBAD at the Helsinki University Hospital, Finland in 2007-2019. The endpoints were early and late mortality, and intervention of the aorta. Results. There were 205 consecutive TBAD patients, 59 complicated and 146 uncomplicated patients (mean age of 66 ± 14, females 27.8%). In-hospital and 30-day mortality rates were higher in complicated patients compared with uncomplicated patients with a statistically significant difference (p = 0.035 and p = 0.015, respectively). After a mean follow-up of 4.9 ± 3.8 years, 36 (25.0%) and 22 (37.9%) TBAD -related adverse events occurred in the uncomplicated and complicated groups, respectively (p = 0.066). Freedom from composite outcome was 83 ± 3% and 69 ± 6% at 1 year, 75 ± 4% and 63 ± 7% at 5 years, 70 ± 5% and 59 ± 7% at 10 years in the uncomplicated group and in the complicated group, respectively (p = 0.052). There were 25 (39.1%) TBAD-related deaths in the overall series and prior aortic aneurysm was the only risk factor for adverse aortic-related events in multivariate analysis (HR 3.46, 95% CI 1.72-6.96, p < 0.001). Conclusion. TBAD is associated with a significant risk of early and late adverse events. Such a risk tends to be lower among patients with uncomplicated dissection, still one fourth of them experience TBAD-related event. Recognition of risk factors in the uncomplicated group who may benefit from early aortic repair would be beneficial.

Long-term outcomes after ascending aortic replacement and aortic root replacement for type A aortic dissection.

OBJECTIVES: We investigated whether the selective use of supracoronary ascending aorta replacement achieves late outcomes comparable to those of aortic root replacement for acute Stanford type A aortic dissection (TAAD). METHODS: Patients who underwent surgery for acute type A aortic dissection from 2005 to 2018 at the Helsinki University Hospital, Finland, were included in this analysis. Late mortality was evaluated with the Kaplan-Meier method and proximal aortic reoperation, i.e. operation on the aortic root or aortic valve, with the competing risk method. RESULTS: Out of 309 patients, 216 underwent supracoronary ascending aortic replacement and 93 had aortic root replacement. At 10 years, mortality was 33.8% after aortic root replacement and 35.2% after ascending aortic replacement (P = 0.806, adjusted hazard ratio 1.25, 95% confidence interval, 0.77-2.02), and the cumulative incidence of proximal aortic reoperation was 6.0% in the aortic root replacement group and 6.2% in the ascending aortic replacement group (P = 0.65; adjusted subdistributional hazard ratio 0.53, 95% confidence interval 0.15-1.89). Among 71 propensity score matched pairs, 10-year survival was 34.4% after aortic root replacement and 36.2% after ascending aortic replacement surgery (P = 0.70). Cumulative incidence of proximal aortic reoperation was 7.0% after aortic root replacement and 13.0% after ascending aortic replacement surgery (P = 0.22). Among 102 patients with complete imaging data [mean follow-up, 4.7 (3.2) years], the estimated growth rate of the aortic root diameter was 0.22 mm/year, that of its area 7.19 mm2/year and that of its perimeter 0.43 mm/year. CONCLUSIONS: When stringent selection criteria were used to determine the extent of proximal aortic reconstruction, aortic root replacement and ascending aortic replacement for type A aortic dissection achieved comparable clinical outcomes.

Spinal cord injury during selective cerebral perfusion and segmental artery occlusion: an experimental study.

OBJECTIVES: Since selective cerebral perfusion (SCP) has been used in aortic arch surgical procedures, the core temperature during lower body circulatory arrest (LBCA) has been steadily rising. Simultaneously, the use of a frozen elephant trunk (FET) graft has been increasing. The safe period of LBCA in relation to spinal cord ischaemic tolerance in combination with segmental artery occlusion by the FET procedure has not been defined. METHODS: Sixteen pigs were assigned to undergo 65 (n = 10) or 90 min (n = 6) of SCP at 28°C with LBCA in combination with occlusion of the 8 uppermost segmental arteries in the thoracic (Th) aorta (15-20 cm FET, Th8-level). The follow-up period consisted of a 6-h intensive period and a 5-day observation period. Near-infrared spectroscopy of the collateral network was used to determine spinal cord oxygenation. The neurological status of the patients was evaluated daily, and the brain and the spinal cord were harvested for a histopathological analysis. RESULTS: Five out of 6 pigs after 90 min and 1 out of 10 pigs after 65 min of LBCA died within 48 h of multiorgan failure. Of the survivors in the 65-min group, 6 out of 9 had paraparesis/paraplegia; the remaining 3 reached normal function. The lone survivor after 90 min of LBCA was paraplegic. Nadir near-infrared spectroscopy of the collateral network values at Th8 and Th10 were 34 (±5) and 39 (±4), and they were reached within 35 min of SCP in both groups. CONCLUSIONS: An extended FET graft with LBCA and SCP durations >65 min at 28°C results in a poor outcome.

Priming protects the spinal cord in an experimental aortic occlusion model.

OBJECTIVES: Paraplegia is a devastating complication in aortic aneurysm surgery. Modifying the spinal cord vasculature is a promising method in spinal cord protection. The aim of this study was to assess whether the spinal cord can be primed by occluding thoracic segmental arteries before simulated aneurysm repair in a porcine model. METHODS: Twelve piglets were randomly assigned to the priming group (6) and the control group (6). Eight uppermost thoracic segmental arteries were occluded at 5-minute intervals in the priming group before a 25-minute aortic crossclamp. In the control group, the aorta was crossclamped for 25 minutes. During the first 5 minutes, 8 segmental arteries were occluded. After the aortic crossclamping, piglets were observed under anesthesia for 5 hours and followed up 5 days postoperatively. Near-infrared spectroscopy, motor-evoked potentials, blood samples, neurology with the modified Tarlov score, and histopathology of the spinal cord were assessed. RESULTS: The median Tarlov score during the first postoperative day was higher in the priming group than in the control group (P = .001). At the end, 50% of the control animals had paraplegia compared with 0% of paraplegia in the priming group. The mean regional histopathologic score differed between the priming group and the control group (P = .02). The priming group had higher motor-evoked potentials during the operation at separate time points. The lactate levels were lower in the priming group compared with the control group (Pg = .001, Pg×t = .18). CONCLUSIONS: Acute priming protects the spinal cord from ischemic injury in an experimental aortic crossclamp model.

Cerebral Oximetry Monitoring in Patients Undergoing Surgery for Stanford Type A Aortic Dissection.

OBJECTIVES: The aim of this study was to evaluate the prognostic impact of cerebral regional oxygen saturation (crSO2) in patients undergoing surgery for Stanford type A aortic dissection (TAAD). DESIGN: Observational, retrospective, institutional study. SETTING: University hospital. PARTICIPANTS: A total of 152 patients who underwent surgery for TAAD from June 2009 to December 2018 at the authors' institution. INTERVENTIONS: Surgery for TAAD using continuous perioperative monitoring of crSO2 with near-infrared cerebral oximetry (INVOS, Medtronic, MN). MEASUREMENTS AND RESULTS: The rates of postoperative stroke/global brain ischemia were 22.4% and of hospital mortality 14.5%. Age, hemoglobin, and cardiogenic shock were independent predictors of nadir crSO2 from both frontal areas at arrival to the operating room. Repeated measures test showed that changes in crSO2 between the first measurement at operating room arrival, at the start of surgery, and at the end of surgery were not significant when measured on the right frontal area (p = 0.632), left frontal area (p = 0.608), as a nadir value from both frontal areas (p = 0.690), and as a difference between frontal areas (p = 0.826) in patients with and without major neurologic complications. Patients who had a nadir crSO2 <40% anytime during the perioperative period, had a numerically higher rate of major neurologic complications (27.3% v 20.4%, p = 0.354), but this difference did not reach statistical significance. The incidence of nadir of crSO2 value <40% at operating room arrival (5.9%, p = 1.000), at the start of surgery (5.3%, p = 0.685), and at the end of surgery (1.3%, p = 1.000) was rather low and not associated with these adverse events. CONCLUSIONS: Derangements in crSO2 detected by cerebral oximetry before and during surgery for TAAD did not predict postoperative stroke and/or global brain ischemia.

Late Outcome after Surgery for Type-A Aortic Dissection.

The aim of this study was to evaluate all-cause mortality and aortic reoperations after surgery for Stanford type A aortic dissection (TAAD). We evaluated the late outcome of patients who underwent surgery for acute TAAD from January 2005 to December 2017 at the Helsinki University Hospital, Finland. We studied 309 patients (DeBakey type I TAAD: 89.3%) who underwent repair of TAAD. Aortic root repair was performed in 94 patients (30.4%), hemiarch repair in 264 patients (85.4%) and partial/total aortic arch repair in 32 patients (10.4%). Hospital mortality was 13.6%. At 10 years, all-cause mortality was 34.9%, and the cumulative incidence of aortic reoperation or late aortic-related death was 15.6%, of any aortic reoperation 14.6%, reoperation on the aortic root 6.6%, on the aortic arch, descending thoracic and/or abdominal aorta 8.7%, on the descending thoracic and/or abdominal aorta 6.4%, and on the abdominal aorta 3.8%. At 10 years, cumulative incidence of reoperation on the distal aorta was higher in patients with a diameter of the descending thoracic aorta ≥35 mm at primary surgery (cumulative incidence in the overall series: 13.2% vs. 4.0%, SHR 3.993, 95%CI 1.316-12.120; DeBakey type I aortic dissection: 13.6% vs. 4.5%, SHR 3.610, 95%CI 1.193-10.913; patients with dissected descending thoracic aorta: 15.8% vs. 5.9%, SHR 3.211, 95%CI 1.067-9.664). In conclusion, surgical repair of TAAD limited to the aortic segments involved by the intimal tear was associated with favorable survival and a low rate of aortic reoperations. However, patients with enlarged descending thoracic aorta at primary surgery had higher risk of late reoperation. Half of the distal aortic reinterventions were performed on the abdominal aorta.

Remote Ischemic Preconditioning in Spinal Cord Protection: A Surviving Porcine Study.

Surgical repair of thoracic aorta can compromise blood flow of the spinal cord. To mitigate spinal cord ischemia (SCI) additional protection methods are needed. In experimental studies remote ischemic preconditioning (RIPC) has proven to be an effective method of protecting organs from ischemia. The aim of the study was to assess efficacy of RIPC in spinal cord protection in a chronic porcine model. Sixteen piglets were assigned into the RIPC group (8) and the control group (8). RIPC was performed using blood pressure cuff in a 5-minute ischemia followed by a 5-minute reperfusion repeating cycles 4 times. The left subclavian artery and all segmental arteries above diaphragm were ligated at 5-minute intervals to accomplish SCI. The follow-up comprised a 4-hour intensive monitoring and a 7-day recovery phase. Blood samples were obtained, motor-evoked potentials and near-infrared spectroscopy (NIRS) of longitudinal back muscles were measured. Paraplegia was assessed every day postoperatively. Histopathological analysis of the spinal cord was performed after 7 days. NIRS values 4 hours after SCI were higher in the RIPC group, 45.5 (44.5-47.0), than in the control group, 41.5 (40.5-44.0) (P = 0.042). Nadir value of NIRS was 43.4 (39.3-46.0) in the RIPC group and 38.9 (38.-40.0) in the control group (P = 0.014). On the first postoperative day the RIPC group reached modified Tarlov score of 3 (2-3) vs 2 (1-2) in the control group (P = 0.024). RIPC hastens the recovery from SCI during the first postoperative day.

Moderate hypothermia with remote ischaemic preconditioning improves cerebral protection compared to deep hypothermia: a study using a surviving porcine model.

OBJECTIVES: The optimal temperature management of hypothermic circulatory arrest is still controversial. Moderate hypothermia preserves cerebral autoregulation and shortens cardiopulmonary bypass (CPB) duration. However, moderate hypothermia alone has inferior organ protection to deep hypothermia, so adjuncts that increase the ischaemic tolerance are needed. Thus, we hypothesized that a combination of remote ischaemic preconditioning (RIPC) and moderate hypothermia would be superior to deep hypothermia alone. METHODS: Sixteen pigs were randomized to either RIPC or control groups (8 + 8). The RIPC group underwent 4 cycles of transient hind limb ischaemia. The RIPC group underwent cooling with CPB to 24°C, and the control group underwent cooling with CPB to 18°C, followed by a 30-min arrest period and subsequent rewarming to 36°C. Measurements of cerebral metabolism were made from sagittal sinus blood samples and common carotid artery blood flow. The permissible periods of hypothermic circulatory arrest were calculated based on these measurements. Neurological recovery was evaluated daily during a 7-day follow-up, and the brain was harvested for histopathological analysis. RESULTS: Six pigs in the RIPC group reached normal neurological function, but none in the control group reached normal neurological function (P = 0.007). The composite neurological score of all postoperative days was higher in the RIPC group than in the control group [55 (52-58) vs 45 (39-51), P = 0.026]. At 24°C, the estimated permissible periods of hypothermic circulatory arrest were 21 (17-25) min in the RIPC group and 11 (9-13) min in the control group (P = 0.007). CONCLUSIONS: RIPC combined with moderate hypothermia provides superior cerebral protection.

Direct Aortic Versus Peripheral Arterial Cannulation in Surgery for Type A Aortic Dissection.

BACKGROUND: It is controversial whether peripheral arterial cannulation may achieve better results than direct aortic cannulation during surgery for Stanford type A aortic dissection. METHODS: From January 2005 to December 2017, 309 consecutive patients underwent surgical repair for acute type A aortic dissection at Helsinki University Hospital, Finland. The early outcomes of patients who underwent surgery with direct aortic cannulation were compared with those of patients in whom peripheral arterial cannulation was used. RESULTS: Direct aortic cannulation was used in 80 patients and peripheral arterial cannulation in 229 patients. Patients who underwent surgery with direct aortic cannulation had hospital mortality (13.8% vs 13.5%, P = .962) and stroke/global brain ischemia (22.3% vs 25%, P = .617) similar to that of patients who had peripheral arterial cannulation. The other secondary outcomes were equally distributed between the unmatched study cohorts. Among 74 propensity score matched pairs, direct aortic cannulation had hospital mortality rates (12.2% vs 9.5%, P = .804) and stroke/global brain ischemia rates (21.6% vs 21.6%, P = 1.000) comparable to those for peripheral arterial cannulation. The composite outcome of hospital mortality/stroke/global brain ischemia (29.7% vs 27%, P = .855), multiple stroke (16.2% vs 17.6%, P = 1.000), renal replacement therapy (11.8% vs 13%, P = 1.000) and length of stay in the intensive care unit (mean, 4.9 ± 4.5 vs 4.8 ± 4.9 days, P = .943) were also equally distributed between these matched cohorts. CONCLUSIONS: In this institutional series, central arterial cannulation allowed a straightforward surgical repair of type A aortic dissection and achieved early outcomes similar to those of peripheral arterial cannulation.

Remote ischaemic preconditioning may prolong permissible period of hypothermic circulatory arrest in a porcine model.

Objectives. The hypothermic circulatory arrest (HCA) is still of paramount importance in aortic arch surgery, but the safe period of the arrest is limited. Remote ischaemic preconditioning (RIPC) prepares the cerebral tissue for ischaemic insult. Prolongation of the permissible period of HCA with RIPC may have a major impact on the outcome of aortic operations requiring cessation of blood flow by decreasing the rate of neurological deficits. Design. Twenty pigs were randomised into the RIPC group (n = 10) and the control group (n = 10). The RIPC group underwent four cycles of transient hind limb ischaemia. Both groups underwent cooling with cardiopulmonary bypass to 11 °C followed by a 45-minute HCA and re-warming to 36 °C. Cerebral blood flow was measured with a transit time ultrasonic flowmeter from the right common carotid artery, and the arteriovenous oxygen difference was calculated from sagittal sinus and arterial blood samples. Measurements were taken at several time points during cooling and warming. Temperature coefficient (Q10) was calculated to determine estimated permissible periods of HCA. Results. The Q10 was 2.27 (1.98-2.58) for the RIPC group and 1.87 (1.61-2.25) for the control group. The permissible period of HCA at 18 °C was 26 minutes (20-33) in the RIPC group and 17 minutes (13-25) in the control group (p = .063)(Data expressed in medians and interquartile ranges). Conclusions. RIPC tends to suppress cerebral metabolism during cooling with cardiopulmonary bypass and may prolong estimated permissible period of HCA.

Safety of direct true lumen cannulation after venous exsanguination: a study in a surviving porcine model†.

OBJECTIVES: Type A aortic dissection requires immediate surgery. Traditional cannulation methods such as the central aortic cannulation with the Seldinger technique and axillary cannulation are primary choices. Yet in the presence of tamponade or severe cardiogenic shock, these can be too time-consuming to complete. Direct true lumen cannulation after venous exsanguination not only avoids this issue but also leads to transient global ischaemia. We studied the safety of direct true lumen cannulation from the aspect of global ischaemia in a surviving porcine model. METHODS: Twelve pigs were randomized to either control or intervention groups (6 + 6). The intervention group underwent simulated direct true lumen cannulation by exsanguination and circulatory arrest for 5 min at 35°C before cardiopulmonary bypass (CPB). Both groups underwent CPB cooling to 25°C followed by a 25-min arrest period and subsequent warming to 36°C. Neuron-specific enolase levels were measured at 6 time-points from blood samples. Near-infrared spectroscopy was used to determine brain oxygenation. The neurological recovery was evaluated daily during a 7-day follow-up, and the brain was harvested for a histopathological analysis after euthanization. RESULTS: All pigs recovered their normal neurological behaviour. The neurobehavioural total score on postoperative day 2 reached borderline statistical significance, thus favouring the intervention group [(9 (8.75-9) vs 6.5 (5.5-9), P = 0.06]. Near-infrared spectroscopy values and neuron-specific enolase levels slightly favoured the control group during the cooling period, but the difference was not clinically significant. The histopathological analysis showed no difference between the groups. CONCLUSIONS: A 5-min period of normothermic global ischaemia before CPB does not impair the neurological outcome following hypothermic circulatory arrest in a surviving porcine model.