Clinical Outcomes After Surgical Revascularization Using No-Touch Versus Conventional Saphenous Vein Grafts: Mid-Term Follow-Up of Propensity Score Matched Cohorts.

Previous studies have demonstrated superior patency of no-touch as compared to conventional saphenous vein grafts in coronary artery bypass grafting. We aimed to compare mid-term clinical outcomes of both techniques in a large cohort of routine patients. We identified all patients undergoing nonemergent primary coronary artery bypass grafting with either no-touch or conventional saphenous vein grafts at our institution between 2000 and 2020. Propensity score matching was used to create adjusted cohorts based on 5288 eligible patients. The primary outcome was the combined endpoint of all-cause mortality and repeat revascularization. Secondary outcomes were individual rates of all-cause mortality and repeat revascularization, surgical complications, and short-term mortality. Propensity score matching resulted in cohorts of no-touch (n = 923) and conventional (n = 923) saphenous vein grafted patients with comparable baseline characteristics. Mean follow-up time was significantly shorter for the no-touch compared to the conventional cohort (4.9 ± 2.3 vs 8.3 ± 2.6 years, P < 0.001). Up to 7-year follow-up, neither the rate of the primary composite endpoint nor death differed significantly between the cohorts. The rate of repeat revascularization was significantly higher in patients in the no-touch cohort (12.9% vs 9.3% at 7-year follow-up, P = 0.022. Post-hoc analysis of percutaneous coronary intervention during follow-up revealed comparable rates of saphenous vein graft failure (no-touch 42/923 (4.6%) vs conventional 32/923 (3.5%), P = 0.286). In this large propensity score matched registry study, coronary artery bypass with no-touch compared to conventional saphenous vein grafting did neither enhance mid-term survival nor reduce the rate of repeat revascularization.

Technical eligibility for endovascular treatment of the aortic arch after open type A aortic dissection repair.

OBJECTIVE: The objective was to report on the technical eligibility of patients previously treated for Stanford type A aorta dissection for endovascular aortic arch repair based on contemporary anatomic criteria for an arch inner-branched stent graft. METHODS: All patients treated for type A aorta dissection from 2004 to 2015 at a single aortic center were identified. Extent of repair and use of circulatory arrest were reported. Survival and reoperation were assessed using Kaplan-Meier and competing risk models. Anatomic assessment was performed using 3-dimensional computed tomography imaging software. Primary outcome was survival of 1 year or more and fulfillment of the arch inner-branched stent graft anatomic criteria. RESULTS: A total of 198 patients were included (158 DeBakey I, 32 DeBakey II, and 8 intramural hematoma). Mortality was 30 days (16.2%), 1 year (16.3%), and 10 years (45.0%). A total of 129 patients had imaging beyond 1 year (mean, 47.8 months), and 89 patients (69.0%) were eligible for arch inner-branched stent grafting. During follow-up, 19 patients (14.7%) met the threshold criteria for aortic arch treatment, of whom 14 (73.7%) would be considered eligible for arch inner-branched stent graft. Patients who underwent type A aorta dissection repair with circulatory arrest and no distal clamp were more often eligible for endovascular repair (88.8%) than those operated with a distal clamp (72.5%; P = .021). Among patients who did not meet the arch inner-branched stent graft anatomic criteria, the primary reasons were mechanical valve (40%) and insufficient proximal seal (30%). CONCLUSIONS: More than two-thirds of patients post-type A aorta dissection repair are technically eligible for endovascular arch inner-branched stent graft repair. The development of devices that can accommodate a mechanical aortic valve and a greater awareness of sufficient graft length would significantly increase availability.

Mechanical Reperfusion Following Prolonged Global Cerebral Ischemia Attenuates Brain Injury.

Previous experiments demonstrated improved outcome following prolonged cerebral ischemia given controlled brain reperfusion using extracorporeal circulation. The current study further investigates this. Young adult pigs were exposed to 30 min of global normothermic cerebral ischemia, achieved through intrathoracic clamping of cerebral arteries, followed by 20 min of isolated mechanical brain reperfusion. Leukocyte-filtered blood was delivered by a roller-pump at fixed pressure and flow. One experimental group additionally had a custom-made buffer solution delivered at 1:8 ratio with the blood. Hemodynamics including intracranial pressure were monitored. Blood gases were from peripheral arteries and the sagittal sinus, and intraparenchymal brain microdialysis was performed. The brains were examined by a neuropathologist. The group with the added buffer showed lower intracranial pressure as well as decreased intraparenchymal glycerol and less signs of excitotoxicity and ischemia, although histology revealed similar degrees of injury. A customized mechanical reperfusion improves multiple parameters after prolonged normothermic global cerebral ischemia. Graphical Abstract The current study investigates if it possible to improve neurological outcomes following prolonged global brain ischemia. The results indicate that a customized mechanical reperfusion protocol can attenuate neurological injury.

No-touch saphenous vein grafts in coronary artery surgery (SWEDEGRAFT): Rationale and design of a multicenter, prospective, registry-based randomized clinical trial.

The SWEDEGRAFT study (ClinicalTrials.gov Identifier: NCT03501303) tests the hypothesis that saphenous vein grafts (SVGs) harvested with the "no-touch" technique improves patency of coronary artery bypass grafts compared with the conventional open skeletonized technique. This article describes the rationale and design of the randomized trial and baseline characteristics of the population enrolled during the first 9 months of enrollment. The SWEDEGRAFT study is a prospective, binational multicenter, open-label, registry-based trial in patients undergoing first isolated nonemergent coronary artery bypass grafting (CABG), randomized 1:1 to no-touch or conventional open skeletonized vein harvesting technique, with a planned enrollment of 900 patients. The primary end point is the proportion of patients with graft failure defined as SVGs occluded or stenosed >50% on coronary computed tomography angiography at 2 years after CABG, earlier clinically driven coronary angiography demonstrating an occluded or stenosed >50% vein graft, or death within 2 years. High-quality health registries and coronary computed tomography angiography are used to assess the primary end point. The secondary end points include wound healing in the vein graft sites and the composite outcome of major adverse cardiac events during the first 2 years based on registry data. Demographics of the first 200 patients enrolled in the trial and other CABG patients operated in Sweden during the same time period are comparable when the exclusion criteria are taken into consideration. RCT# NCT03501303.

Long-term survival and frequency of reinterventions after proximal aortic surgery: a retrospective study†.

OBJECTIVES: We sought to analyse perioperative outcome, long-term mortality, frequency and causes of reintervention, and survival benefit in a contemporary cohort of patients undergoing proximal thoracic aortic surgery. METHODS: Participants comprised all patients undergoing open surgery for proximal thoracic aortic aneurysm (TAA) (n = 319) and thoracic aortic dissection type A (TAD) (n = 229) during 2005-2014 at the Department of Thoracic Surgery, Uppsala University Hospital. Long-term survival was compared to age- and sex-matched controls. Perioperative mortality and morbidity, event-free survival and causes of reoperation were also analysed. RESULTS: Long-term mortality was normalized in patients with TAA, and a survival benefit was seen as early as 20 months when corrected for time lost due to perioperative mortality. Long-term survivors undergoing surgery for TAD, on the other hand, had a 10-year mortality of 130% [95% confidence interval (95% CI) 120-140%] compared to age- and sex-matched controls. Moreover, their event-free survival was half that of patients with TAA (hazard ratio 2.3; 95% CI 1.7-3.2). Reintervention (i.e. reoperation or thoracic endovascular aortic repair) was also twice as common in the TAD patients (odds ratio 2.0; 95% CI 1.1-3.5). The dominant causes for reoperation among TAD patients were aortic insufficiency, aortic arch aneurysm and infection. CONCLUSIONS: Surgery for TAA is relatively safe, normalizes long-term mortality and confers an early survival benefit. However, TAD surgery carries a high risk of perioperative mortality and morbidity, as well as increased long-term mortality and risk of reintervention.

Long-term clinical outcomes after coronary artery bypass grafting with pedicled saphenous vein grafts.

BACKGROUND: Coronary artery bypass grafting (CABG) using saphenous vein grafts (SVG) is vitiated by poor long-term patency of the vein grafts. Pedicled SVG harvested with the "no-touch" (NT) technique have demonstrated improved patency and could confer better outcomes. We aim to compare long-term results after CABG where NT or conventional technique was used for vein graft harvesting in a hypothesis-generating registry-based study. METHODS: Two propensity score matched cohorts (1349 patients) undergoing CABG with veins harvested with NT (NTT) or conventional (CT) technique in Sweden over the period 2005-2015 were used to compare long-term outcomes. Mortality, postoperative incidence of coronary angiography and need for reintervention was recorded and multivariable hazard ratios adjusted for risk factors were calculated. RESULTS: The mean follow-up time (SD) was 6.8 (3.3) years for NTT and 6.6 (3.2) years for CT. The adjusted hazard ratios for death, first angiography and need for reintervention for NTT patients were (95% CI) 0.97 (0.80-1.19), 0.76 (0.63-0.93), 0.91 (0.78-1.05), and 0.91 (0.71-1.17), respectively. Failed grafts were found in 43.2% of NTT patients and 53.6% of CT patients at angiography. CONCLUSIONS: In this study NT grafting was associated with a lower risk for repeat angiography, however no difference could be observed for mortality and need for reintervention. The earlier reported improvements in patency of NT veins could possibly be reflected in an improved clinical outcome during the first 10 years after surgery.

Protein Profiling in Serum and Cerebrospinal Fluid Following Complex Surgery on the Thoracic Aorta Identifies Biological Markers of Neurologic Injury.

Surgery on the arch or descending aorta is associated with significant risk of neurological complications. As a consequence of intubation and sedation, early neurologic injury may remain unnoticed. Biomarkers to aid in the initial diagnostics could prove of great value as immediate intervention is critical. Twenty-three patients operated in the thoracic aorta with significant risk of perioperative neurological injury were included. Cerebrospinal fluid (CSF) and serum were obtained preoperatively and in the first and second postoperative days and assessed with a panel of 92 neurological-related proteins. Three patients suffered spinal cord injury (SCI), eight delirium, and nine hallucinations. There were markers in both serum and CSF that differed between the affected and non-affected patients (SCI; IL6, GFAP, CSPG4, delirium; TR4, EZH2, hallucinations; NF1). The study identifies markers in serum and CSF that reflect the occurrence of neurologic insults following aortic surgery, which may aid in the care of these patients.

Quality of life is not improved after mitral valve surgery combined with epicardial left atrial cryoablation as compared with mitral valve surgery alone: a substudy of the double blind randomized SWEDish Multicentre Atrial Fibrillation study (SWEDMAF).

Aims: Concomitant surgical ablation of atrial fibrillation (AF) in patients undergoing mitral valve surgery (MVS) has almost become routine despite lack of convincing information about improved quality-of-life (QOL) and clinical benefit. Quality-of-life was therefore assessed after MVS with or without epicardial left atrial cryoablation. Methods and results: Sixty-five patients with permanent AF randomized to MVS with or without left atrial cryoablation, in the double-blinded multicentre SWEDMAF trial, replied to the Short Form 36 QOL survey at 6 and 12 months follow-up. The QOL scores at 12 month follow-up did not differ significantly between patients undergoing MVS combined with cryoablation vs. those undergoing MVS alone regarding Physical Component Summary mean 42.8 (95% confidence interval 38.3-47.3) vs. mean 44.0 (40.1-47.7), P = 0.700 or Mental Component Summary mean 53.1 (49.7-56.4) vs. mean 48.4 (44.6-52.2), P = 0.075. All patients, irrespective of allocated procedure, reached the same QOL after surgery as an age-matched Swedish general population. The Physical Component Summary in patients with sinus rhythm did also not differ from those in AF at 12 months; mean 45.4 (42.0-48.7) vs. mean 40.5 (35.5-45.6), P = 0.096) nor was there a difference in Mental Component Summary; mean 51.0 (48.0-54.1) vs. mean 49.6 (44.6-54.5), P = 0.581). Conclusion: Left atrial cryoablation added to MVS does not improve health-related QOL in patients with permanent AF, a finding that raises concerns regarding recommendations made for this combined procedure.

Application of cryoenergy to improve septal exposure during transaortic septal myectomy in hypertrophic obstructive cardiomyopathy.

For the past few decades, the transaortic septal myectomy (Morrow's procedure) has been the gold standard for treating severe left ventricular outflow tract obstruction in hypertrophic obstructive cardiomyopathy (HOCM) patients. 30-day mortality has been reported at less than 1% in dedicated centers. However, in a subgroup of patients, the interventricular septal obstruction is localized very distally, below the aortic valve plane, and the transaortic approach can be very challenging. A subset of these patients can present with residual obstruction after surgery, due to inadequate length of septal excision, leading to reoperation. The aim of this work is to illustrate an original application of cryoenergy to improve the transaortic exposure of the interventricular septum and thus enable surgeons to perform very distal myectomies in HOCM patients.

Blood Flow Quantitation by Positron Emission Tomography During Selective Antegrade Cerebral Perfusion.

BACKGROUND: Perfusion strategies during aortic surgery usually comprise hypothermic circulatory arrest (HCA), often combined with selective antegrade cerebral perfusion (SACP) or retrograde cerebral perfusion. Cerebral blood flow (CBF) is a fundamental parameter for which the optimal level has not been clearly defined. We sought to determine the CBF at a pump flow level of 6 mL/kg/min, previously shown likely to provide adequate SACP at 20°C in pigs. METHODS: Repeated positron emission tomography (PET) scans were used to quantify the CBF and glucose metabolism throughout HCA and SACP including cooling and rewarming. Eight pigs on cardiopulmonary bypass were assigned to either HCA alone (n = 4) or HCA+SACP (n = 4). The CBF was measured by repeated [15O]water PET scans from baseline to rewarming. The cerebral glucose metabolism was examined by [18F]fluorodeoxyglucose PET scans after rewarming to 37°C. RESULTS: Cooling to 20°C decreased the cortical CBF from 0.31 ± 0.06 at baseline to 0.10 ± 0.02 mL/cm3/min (p = 0.008). The CBF was maintained stable by SACP of 6 mL/kg/min during 45 minutes. After rewarming to 37°C, the mean CBF increased to 0.24 ± 0.07 mL/cm3/min, without significant differences between the groups at any time-point exclusive of the HCA period. The net cortical uptake (Ki) of [18F]fluorodeoxyglucose after rewarming showed no significant difference between the groups. CONCLUSIONS: Cooling autoregulated the CBF to 0.10 mL/cm3/min, and 45 minutes of SACP at 6 mL/kg/min maintained the CBF in the present model. Cerebral glucose metabolism after rewarming was similar in the study groups.

Mechanical reperfusion with leucocyte-filtered blood does not prevent injury following global cerebral ischaemia.

Objectives: Prolonged global cerebral ischaemia leads to irreversible injury, often with lethal outcome. Brain injuries are partly caused by the uncontrolled reperfusion that occurs once the circulation is re-established. Recent animal experiments suggest that controlled reperfusion following lengthy ischaemia might prevent severe brain injury. This study aimed at further exploring cerebral alterations and outcome following prolonged global cerebral ischaemia and mechanically manipulated reperfusion. Methods: Three groups of pigs were included; one sham operated ( n = 3) and two that underwent 30-min global cerebral ischaemia. All vessels that supply the brain were isolated intrathoracically, after which they were occluded for 30 min in the ischaemic groups. In one of the ischaemic groups uncontrolled reperfusion was applied (URep, n = 6), i.e. normal circulation was restored 30 min after arrested cerebral circulation. The second ischaemic group received mechanical reperfusion (MRep, n = 6) with leucocyte-filtered blood at constant flow and pressure for 20 min using extracorporeal circulation following the 30-min ischaemia, after which normal blood flow resumed. All animals were monitored for 3 h after start of uncontrolled reperfusion. Haemodynamic parameters, arterial and sagittal sinus blood gases, cerebral oxygen extraction rates and intraparenchymal biomarkers using microdialysis were measured. Brain histology was performed post-mortem. Results: Global brain ischaemia led to the same extent of severe morphological changes at the level of light microscopy in the two ischaemic experimental groups, regardless of reperfusion protocol. Furthermore, no significant differences were found between the URep and MRep groups regarding cerebral blood gases or microdialysis biomarkers. Conclusions: Mechanical reperfusion following the current protocol does not modify brain alterations caused by 30 min of arrested cerebral circulation.

Trace Element Changes in Thoracic Aortic Dissection.

Thoracic aortic dissection is a life-threatening condition with an incompletely understood pathogenesis. Trace elements are essential for the functioning of different processes in the body, including the immune system and associated responses to infection/inflammation. Because inflammation may be part of the pathogenesis of thoracic aortic dissection, we investigated whether trace element changes associated with inflammation occur in serum and tissue samples during the disease. The study included 21 patients undergoing surgery for thoracic aortic dissection, 10 forensic autopsy specimens for tissue controls and 23 healthy blood donors for serum controls. Levels of magnesium (Mg), calcium (Ca), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd) and mercury (Hg) were measured in the aortic tissue and serum by inductively coupled plasma-mass spectrometry (ICP-MS). In the serum, Ca, V, Cu and Zn decreased, whereas Fe increased. In the tissue, Cu and Zn decreased and Fe tended to increase. The Cu/Zn ratio in the serum, a marker of infection/inflammation, did not change in the patients. Concerning trace element changes in the serum and tissue, our data do not support the hypothesis that inflammation is involved in the pathogenesis of thoracic aortic dissection.

Influence of blood/tissue differences in contrast agent relaxivity on tracer-based MR perfusion measurements.

PURPOSE: Perfusion assessment by monitoring the transport of a tracer bolus depends critically on conversion of signal intensity into tracer concentration. Two main assumptions are generally applied for this conversion; (1) contrast agent relaxivity is identical in blood and tissue, (2) change in signal intensity depends only on the primary relaxation effect. The purpose of the study was to assess the validity and influence of these assumptions. MATERIALS AND METHODS: Blood and cerebral tissue relaxivities r1, r2, and r2* for gadodiamide were measured in four pigs at 1.5 T. Gadolinium concentration was determined by inductively coupled plasma atomic emission spectroscopy. Influence of the relaxivities, secondary relaxation effects and choice of singular value decomposition (SVD) regularization threshold was studied by simulations. RESULTS: In vivo relaxivities relative to blood concentration [in s(-1) mM(-1) for blood, gray matter (GM), white matter (WM)] were for r1 (2.614 ± 1.061, 0.010 ± 0.001, 0.004 ± 0.002), r2 (5.088 ± 0.952, 0.091 ± 0.008, 0.059 ± 0.014), and r2* (13.292 ± 3.928, 1.696 ± 0.157, 0.910 ± 0.139). Although substantial, by a nonparametric test for paired samples, the differences were not statistically significant. The GM to WM blood volume ratio was estimated to 2.6 ± 0.9 by r1, 1.6 ± 0.3 by r2, and 1.9 ± 0.2 by r2*. Secondary relaxation was found to reduce the tissue blood flow, as did the SVD regularization threshold. CONCLUSION: Contrast agent relaxivity is not identical in blood and tissue leading to substantial errors. Further errors are introduced by secondary relaxation effects and the SVD regularization.

Morphologic outcome after endovascular treatment of complicated type B aortic dissection.

PURPOSE: To investigate the long-term morphologic changes of the aorta after thoracic endovascular aortic repair (TEVAR) for acute complicated type B aortic dissection and to analyze whether these changes differed between DeBakey class IIIa and IIIb dissections. MATERIALS AND METHODS: During the period 1999-2009, 58 patients with acute complicated type B aortic dissection were treated with TEVAR. Seven patients lacked follow-up data, leaving 51 patients-17 patients with DeBakey IIIa aortic dissection and 34 patients with DeBakey IIIa aortic dissection IIIb-for inclusion in the study. Computed tomography scans performed before and after TEVAR were evaluated. Maximum thoracic and abdominal aortic diameters and diameters of the true lumen and false lumen at the level of the maximum aortic diameter in the thorax and abdomen were analyzed as well as degree of thrombosis of the false lumen. RESULTS: There was an overall significant reduction of the thoracic aortic diameter, increased true lumen diameter, and reduced false lumen diameter (P < .05). Total thrombosis of the false lumen, with or without reintervention, was seen in 53% of all patients, in 41% primarily and in 12% after reintervention. The IIIa group had a higher degree of total false lumen thrombosis. All patients in the IIIb group had total thrombosis of the false lumen along the stent graft. CONCLUSIONS: Long-term follow-up showed favorable aortic remodeling after TEVAR for acute complicated type B aortic dissection. Total thrombosis of the false lumen occurred more often in patients with DeBakey IIIa aortic dissection compared with patients with DeBakey IIIb aortic dissection.

Experimental treatment of superior venous congestion during cardiopulmonary bypass.

OBJECTIVES: Superior venous outflow obstruction affects cerebral perfusion negatively by reducing cerebral perfusion pressure (CPP). We present a randomized study designed to compare two alternative strategies to preserve the CPP during superior vena cava (SVC) congestion and cardiopulmonary bypass (CPB). METHODS: Fourteen pigs on bi-caval CPB were subjected to 75% occlusion of the SVC flow. CPP was restored either by vasopressor treatment (VP, n = 7) or by partial relief (PR) of the congestion (n = 7). The cerebral effects of the interventions were studied for 60 min with intracranial pressure (ICP) monitoring, cerebral blood flow measurement, the near-infrared light spectroscopy tissue oxygen saturation index (StO2), arterial and venous blood gas analyses and serial measurements of the glial cell damage marker protein S100ß. RESULTS: Both strategies restored the CPP to baseline levels and no signs of severe ischaemia were observed. In the PR group, the venous and ICPs were normalized in response to the intervention, while in the VP group those parameters remained elevated throughout the experiment. The haemoglobin oxygen saturation in the sagittal sinus (SsagO2) was increased by both VP and PR, while significant improvement in the StO2 was observed only in the PR group. The S100ß concentrations were similar in the two groups. CONCLUSIONS: Experimental SVC obstruction during CPB may reduce the CPP, resulting in impaired cerebral perfusion. Both vasopressor treatment and improved venous drainage can, in the short term, individually restore the CPP during these circumstances.

Outcome of endovascular treatment of traumatic aortic transection.

OBJECTIVE: The purpose of this study was to analyze our experience of thoracic endovascular aortic repair (TEVAR) in patients with traumatic aortic transection. METHODS: This was a single-center consecutive case series that was conducted at the Uppsala University Hospital, Tertiary Referral Center. There were a total of 17 consecutive patients undergoing TEVAR for traumatic thoracic aortic transection. All patients undergoing TEVAR for aortic transection were registered prospectively and their medical records were reviewed regarding technical details, mechanism of injury, and concomitant injuries. Long-term outcome was analyzed with respect to need for reintervention and survival. RESULTS: Between 2001 and 2010, 17 patients underwent TEVAR for traumatic aortic injury. Median age was 42 years (range, 18-77 years), and 15 of 17 patients (88%) were men. Fourteen patients had been involved in motor vehicle accidents, two had fallen from heights, and one fell off a bicycle on a slope. In all cases, the aortic injury was located in the proximity of the origin of the left subclavian artery. All patients had concomitant injuries. In all patients, a single stent graft was sufficient to exclude the injured part of the aorta. The median cover length was 120 mm (range, 100-200 mm). In-hospital mortality was 24% (4 of 17 patients). One patient died perioperatively and three postoperatively, two from brain injuries and one from multiorgan failure. After a median follow-up of 36 months (range, 10-98 months), three patients underwent reintervention (18%), each patient only once; one for a type I endoleak, and two for pseudocoarctation secondary to stent graft infolding. Two were treated endovascularly, and one had a stent graft explantation. CONCLUSIONS: Endovascular repair allows rapid and minimally invasive therapy in patients with traumatic aortic injury with good technical results. The outcome is highly dependent on the severity of other concurrent injuries.

Atrial function after left atrial epicardial cryoablation for atrial fibrillation in patients undergoing mitral valve surgery.

PURPOSE: To explore the effects on atrial and ventricular function of restoring sinus rhythm (SR) after epicardial cryoablation and closure of the left atrial appendage (LAA) in patients with mitral valve disease and atrial fibrillation (AF) undergoing surgery. METHODS: Sixty-five patients with permanent AF were randomized to mitral valve surgery combined with left atrial epicardial cryoablation and LAA closure (ABL group, n = 30) or to mitral valve surgery alone (control group, n = 35). Two-dimensional and Doppler echocardiography were performed before and 6 months after surgery. RESULTS: At 6 months, 73% of the patients in the ABL group and 46% of the controls were in SR. Patients in SR at 6 months had a reduction in their left ventricular diastolic diameter while the left ventricular ejection fraction was unchanged. In patients remaining in AF, the left ventricular ejection fraction was lower than at baseline. The left atrial diastolic volume was reduced after surgery, more in patients with SR than AF. In patients in SR, the peak velocity during the atrial contraction and the reservoir function were lower in the ABL group than in the control group. CONCLUSIONS: In patients in SR, signs of atrial dysfunction were observed in the ABL but not the control group. Atrial dysfunction may have existed before surgery, but the difference between the groups implies that the cryoablation procedure and/or closure of the LAA might have contributed.

Minimal safe arterial blood flow during selective antegrade cerebral perfusion at 20° centigrade.

BACKGROUND: Selective antegrade cerebral perfusion (SACP) enables surgery on the aortic arch, where cerebral ischemia may cause neurologic sequels. This study aims to identify the minimum arterial flow level to maintain adequate cerebral perfusion during SACP in deep hypothermia in the pig. METHODS: Two groups of pigs were subjected to SACP at 20(°)C α-stat. In group 1 (n = 6), flow was stepwise adjusted from 8-6-4-2-8 mL · kg(-1) · min(-1) and in group 2 (n = 5), flow was kept constant at 6 mL · kg(-1) · min(-1). Magnetic resonance imaging and spectroscopy were performed at each flow level together with hemodynamic monitoring and blood gas analysis. The biochemical marker of cerebral damage protein S100ß was measured in peripheral blood. RESULTS: Decreased mixed venous oxygen saturation and increased lactate in magnetic resonance spectroscopy was seen as a sign of anaerobic metabolism below 6 mL · kg(-1) · min(-1). No ischemic damage was seen on diffusion-weighted imaging, but the concentrations of S100ß were significantly elevated in group 1 compared with group 2 at the end of the experiment (p < 0.05). Perfusion-weighted imaging showed coherence between flow setting and cerebral perfusion, increase of blood volume across time, and regional differences in perfusion during SACP. CONCLUSIONS: The findings suggest an ischemic threshold close to 6 mL · kg(-1) · min(-1) in the present model. Regional differences in perfusion during SACP may be of pathogenic importance to focal cerebral ischemia.