Peter Svenarud

Effect of CO2 insufflation on the number and behavior of air microemboli in open-heart surgery: A randomized clinical trial

Background—The risks that the presence of air microemboli implies in open-heart surgery have recently been emphasized by reports that their number is correlated with the degree of postoperative neuropsychological disorder. Therefore, we studied the effect of CO2 insufflation into the cardiothoracic wound on the incidence and behavior of microemboli in the heart and ascending aorta. Methods and Results—Twenty patients undergoing single-valve surgery were randomly divided into 2 groups. Ten patients were insufflated with CO2 via a gas diffuser, and 10 were not. Microemboli were ascertained by intraoperative transesophageal echocardiography (TEE) and recorded on videotape from the moment that the aortic cross-clamp was released until 20 minutes after end of cardiopulmonary bypass (CPB). The surgeon performed standard de-airing maneuvers without being aware of TEE findings. Postoperatively, a blinded assessor determined the maximal number of gas emboli during each consecutive minute in the left atrium, left ventricle, and ascending aorta. The 2 groups did not differ in the usual clinical parameters. The median number of microemboli registered during the whole study period was 161 in the CO2 group versus 723 in the control group (P <0.001). Corresponding numbers for the left atrium were 69 versus 340 (P <0.001), left ventricle 68 versus 254 (P <0.001), and ascending aorta 56 versus 185 (P <0.001). In the CO2 group, the median number of detectable microemboli after CPB fell to zero 7 minutes after CPB versus 19 minutes in the control group (P <0.001). Conclusions—Insufflation of CO2 into the thoracic wound markedly decreases the incidence of microemboli.

Arginase Inhibition Improves Endothelial Function in Patients With Coronary Artery Disease and Type 2 Diabetes Mellitus

Background— Endothelial dysfunction plays an important role in the early development of atherosclerosis and vascular complications in type 2 diabetes mellitus. Increased expression and activity of arginase, metabolizing the nitric oxide substrate L-arginine, may result in reduced production of nitric oxide and thereby endothelial dysfunction. We hypothesized that inhibition of arginase activity improves endothelial function in patients with coronary artery disease (CAD) and type 2 diabetes mellitus. Methods and Results— Three groups of subjects were included: 16 patients with CAD, 16 patients with CAD and type 2 diabetes mellitus (CAD+Diabetes), and 16 age-matched healthy control subjects. Forearm endothelium-dependent and endothelium-independent vasodilatation were assessed with venous occlusion plethysmography before and during intra-arterial infusion of the arginase inhibitor N&ohgr;-hydroxy-nor-L-arginine (nor-NOHA; 0.1 mg/min). Nor-NOHA was also coinfused with the nitric oxide synthase inhibitor (NG-monomethyl L-arginine). The expression of arginase was determined in the internal mammary artery of patients undergoing bypass surgery. Nor-NOHA markedly increased endothelium-dependent vasodilatation (up to 2-fold) in patients with CAD+Diabetes and CAD (P<0.001) but not in the control group. NG-monomethyl L-arginine completely inhibited the increase in endothelium-dependent vasodilatation induced by nor-NOHA. Endothelium-independent vasodilatation was slightly improved by nor-NOHA in the CAD+Diabetes group. Arginase I was expressed in vascular smooth muscle cells and endothelial cells, and arginase II was expressed in endothelial cells of patients with and without diabetes mellitus. Conclusions— Arginase inhibition markedly improves endothelial function in patients with CAD and type 2 diabetes mellitus suggesting that increased arginase activity is a key factor in the development of endothelial dysfunction.

Early and intermediate outcome after aortic valve replacement with a sutureless bioprosthesis: Results of a multicenter study

OBJECTIVE The aim of this study was to evaluate the outcome of aortic valve replacement with the sutureless Perceval S aortic valve bioprosthesis (Sorin Biomedica Cardio Srl, Saluggia, Italy). METHODS This is a retrospective analysis of 314 patients (mean age, 77.9 ± 5.0 years, mean European System for Cardiac Operative Risk Evaluation II, 9.0% ± 7.6%) who underwent aortic valve replacement with the Perceval S valve with (94 patients) or without (220 patients) concomitant coronary artery bypass surgery at 5 European centers. RESULTS The Perceval S valve was successfully implanted in all but 1 patient (99.7%). The mean aortic crossclamping time was 43 ± 20 minutes (isolated procedure, 39 ± 15 minutes; concomitant coronary surgery, 52 ± 26 minutes). Severe paravalvular leak occurred in 2 patients (0.6%). In-hospital mortality was 3.2% (1.4% after isolated procedure and 7.4% after concomitant coronary surgery). In-hospital mortality was 2.8% and 4.0% among patients with a European System for Cardiac Operative Risk Evaluation II less than 10% and 10% or greater, respectively (P = .558). Octogenarians had slightly higher in-hospital mortality (5.2% vs 2.0%, P = .125; after isolated procedure: 2.7% vs 0.7%, P = .223; after concomitant coronary surgery: 9.5% vs 5.8%, P = .491) compared with younger patients. Full sternotomy did not increase the in-hospital mortality risk compared with ministernotomy or minithoracotomy access (1.3% vs 1.4%, when adjusted for baseline covariates: P = .921; odds ratio, 0.886; 95% confidence interval, 0.064-12.346). One-year survival was 90.5%. Freedom from valve-related mortality, stroke, endocarditis, and reoperation was 99.0%, 98.1%, 99.2%, and 98.3%, respectively. CONCLUSIONS The sutureless Perceval S valve is associated with excellent early survival in high-risk patients, particularly among those undergoing an isolated procedure. Further studies are needed to prove the durability of this bioprosthesis.

European Multicenter Study on Coronary Artery Bypass Grafting (E-CABG registry): Study Protocol for a Prospective Clinical Registry and Proposal of Classification of Postoperative Complications

BackgroundClinical evidence in coronary surgery is usually derived from retrospective, single institutional series. This may introduce significant biases in the analysis of critical issues in the treatment of these patients. In order to avoid such methodological limitations, we planned a European multicenter, prospective study on coronary artery bypass grafting, the E-CABG registry.DesignThe E-CABG registry is a multicenter study and its data are prospectively collected from 13 centers of cardiac surgery in university and community hospitals located in six European countries (England, Italy, Finland, France, Germany, Sweden). Data on major and minor immediate postoperative adverse events will be collected. Data on late all-cause mortality, stroke, myocardial infarction and repeat revascularization will be collected during a 10-year follow-up period. These investigators provided a score from 0 to 10 for any major postoperative adverse events and their rounded medians were used to stratify the severity of these complications in four grades. The sum of these scores for each complication/intervention occurring after coronary artery bypass grafting will be used as an additive score for further stratification of the prognostic importance of these events.DiscussionThe E-CABG registry is expected to provide valuable data for identification of risk factors and treatment strategies associated with suboptimal outcome. These information may improve the safety and durability of coronary artery bypass grafting. The proposed classification of postoperative complications may become a valuable research tool to stratify the impact of such complications on the outcome of these patients and evaluate the burden of resources needed for their treatment.Clinical Trials numberNCT02319083

Cerebral Microembolism During Coronary Angiography A Randomized Comparison Between Femoral and Radial Arterial Access

Background and Purpose— Microemboli observed during coronary angiography can cause silent ischemic cerebral lesions. The aim of this study was to investigate if the number of particulate cerebral microemboli during coronary angiography is influenced by access site used. Methods— Fifty-one patients with stable angina pectoris referred for coronary angiography were randomized to right radial or right femoral arterial access. The number of particulate microemboli passing the middle cerebral arteries was continuously registered with transcranial Doppler. Results— The median (minimum–maximum range) numbers of particulate emboli were significantly higher with radial 10 (1–120) than with femoral 6 (1–19) access. More particulate microemboli passed the right middle cerebral artery with the radial access. Conclusions— This study indicates that the radial access used for coronary angiography generates more particulate cerebral microemboli than the femoral access and thus may influence the occurrence of silent cerebral injuries.

Intermittent or continuous carbon dioxide insufflation for de-airing of the cardiothoracic wound cavity? An experimental study with a new gas-diffuser.

Insufflation of carbon dioxide into the chest wound is used in open-heart surgery to de-air the heart and great vessels. In a cardiothoracic wound model, we compared the degree of air displacement achieved by a new insufflation device, a gas-diffuser, with that of a thin open-ended tube during steady-state and with carbon dioxide flows of 2.5, 5, 7.5, and 10 L/min. We also studied air displacement at the start of and after discontinuation of carbon dioxide insufflation with the gas-diffuser and evaluated the influence of an open pleura. During steady state, the gas-diffuser produced efficient air displacement in the wound cavity model at carbon dioxide flows of ≥5 L/min (≤0.65% remaining air), whereas the open-ended tube was inefficient (≥82% remaining air) at all studied carbon dioxide flows (P < 0.001). An open pleural cavity prolonged the time needed to obtain a high degree of air displacement in the wound cavity (P = 0.001). Carbon dioxide insufflation of the cardiothoracic wound cavity should be initiated at a carbon dioxide flow of 10 L/min at least 1 min before the incision of the heart and great vessels and should be continued at a carbon dioxide flow of at least 5 L/min until surgical closure.

Aortic valve replacement through full sternotomy with a stented bioprosthesis versus minimally invasive sternotomy with a sutureless bioprosthesis

OBJECTIVES The aim of this study was to analyse early postoperative outcomes and 2-year survival after aortic valve replacement (AVR) through a ministernotomy with a sutureless bioprosthesis implantation compared with a full sternotomy with implantation of a stented bioprosthesis. METHODS Patients who underwent primary isolated non-emergent AVR at six European centres were included in the study. Of these, 182 (32%) underwent a ministernotomy with a sutureless bioprosthesis (ministernotomy sutureless group) and 383 (68%) a full sternotomy with a stented bioprosthesis (full sternotomy stented group). Propensity score matching was used to reduce selection bias. RESULTS In the overall cohort, 30-day mortality was 1.6 and 2.1%, and 2-year survival was 92 and 92% in the ministernotomy sutureless group and in the full sternotomy stented group, respectively. Propensity score matching resulted in 171 pairs with similar characteristics and operative risk. Aortic cross-clamp (40 vs 65 min, P < 0.001) and cardiopulmonary bypass time (69 vs 87 min, P < 0.001) were shorter in the ministernotomy sutureless group. Patients undergoing ministernotomy received less packed red blood cells but the risk for postoperative permanent pacemaker implantation was higher. There were no differences regarding 30-day mortality or 2-year survival between the two groups. CONCLUSIONS AVR through a ministernotomy with implantation of a sutureless bioprosthesis was associated with shorter aortic cross-clamp and cardiopulmonary bypass time and less transfusion of packed red blood cells, but a higher risk for postoperative permanent pacemaker implantation compared with a full sternotomy with a stented bioprosthesis.

Ministernotomy Versus Full Sternotomy Aortic Valve Replacement With a Sutureless Bioprosthesis: A Multicenter Study

BACKGROUND The aim of this study was to analyze early postoperative outcomes and 2-year survival after aortic valve replacement (AVR) with the sutureless Perceval bioprosthesis (Sorin Biomedica Cardio Srl, Salluggia, Italy) performed through ministernotomy compared with full sternotomy. METHODS This was a study of 267 consecutive patients who underwent isolated AVR with the sutureless Perceval bioprosthesis between 2007 and 2014 at 6 European centers. Of these, 189 (70.8%) were performed through ministernotomy and 78 through a full sternotomy. Propensity score matching was used to reduce selection bias. RESULTS In the overall cohort of ministernotomy and full sternotomy patients, in-hospital mortality was 1.1% and 2.6% and 2-year survival was 92% and 91%, respectively. Propensity score matching resulted in 56 pairs with similar characteristics and operative risk. Aortic cross-clamp (44 minutes in both groups, p = 0.931) and cardiopulmonary bypass time (69 vs 74 minutes, p = 0.363) did not differ between the groups. Apart from higher values in the ministernotomy group for postoperative peak gradients (28.1 vs 23.3 mm Hg, p = 0.026) and mean aortic valve gradients (15.2 vs 11.7 mm Hg, p = 0.011), early postoperative outcomes did not differ in the propensity-matched cohort. There were no differences in the in-hospital mortality rate or 2-year survival between the groups. CONCLUSIONS AVR with the sutureless Perceval bioprosthesis through a ministernotomy was a safe and reproducible procedure that was not associated with prolonged aortic cross-clamp or cardiopulmonary bypass time compared with a full sternotomy. Early postoperative outcomes and 2-year survival were comparable between patients undergoing ministernotomy and full sternotomy.

Local Insufflation of Warm Humidified CO2 Increases Open Wound and Core Temperature During Open Colon Surgery: A Randomized Clinical Trial

BACKGROUND:The open surgical wound is exposed to cold and dry ambient air resulting in heat loss through radiation, evaporation, and convection. Also, general and neuraxial anesthesia decrease the patient’s core temperature. Despite routine preventive measures mild intraoperative hypothermia is still common and contributes to postoperative morbidity and mortality. We hypothesized that local insufflation of warm fully humidified CO2 would increase both the open surgical wound and core temperature. METHODS:Eighty-three patients undergoing open colon surgery were equally and parallelly randomized to either standard warming measures including forced-air warming, warm fluids, and insulation of limbs and head, or to additional local wound insufflation of warm (37°C) humidified (100% relative humidity) CO2 at a laminar flow (10 L/min) via a gas diffuser. Wound surface and core temperatures were followed with a heat-sensitive infrared camera and a tympanic thermometer. RESULTS:The mean wound area temperature during surgery was 31.3°C in the warm humidified CO2 group compared with 29.6°C in the control group (P < 0.001, 95% confidence interval [CI], 1.2°C to 2.3°C). Also, the mean wound edge temperature during surgery was 30.1°C compared with 28.5°C in the control group (P < 0.001, 95% CI, 0.2°C to 0.7°C). Mean core temperature before start of surgery was similar with 36.7°C ± 0.5°C in the warm humidified CO2 group versus 36.6°C ± 0.5°C in the control group (95% CI, 0.4 to −0.1°C). At end of surgery, the 2 groups differed significantly with 36.9 ± 0.5°C in the warm humidified CO2 group versus 36.3 ± 0.5°C in the control group (P < 0.001, 95% CI, 0.38°C to 0.82°C). Moreover, only 8 patients of 40 in the warm humidified CO2 group had a core temperature <36.5°C (20%, 95% CI, 7 to 33%), whereas in the control group this was the case in 24 of 39 (62%, 95% CI, 46% to 78%, P = 0.001) patients (difference of the percentages between the groups 42%, 95% CI, 22% to 61%, P < 0.001). With a cutoff at <36.0°C none of the patients in the warm humidified CO2 group compared with 7 patients (18%, 95% CI, 5% to 31%, P = 0.005) in the control group was hypothermic at end of surgery (difference of the percentages between the groups 18%, 95% CI, 6% to 30%, P = 0.005). The median (25th/75th percentile) operating time was 181.5 (147.5/288) minutes in the warm humidified CO2 group versus 217 (149/288) minutes in the control group (P = 0.312). Clinical variables did not show any significant differences between the groups. CONCLUSIONS:Insufflation of warm fully humidified CO2 in an open surgical wound cavity increases surgical wound and core temperatures and helps to maintain normothermia.

Extracorporeal membrane oxygenation as a rescue of intractable ventricular fibrillation and bridge to heart transplantation.

Extracorporeal membrane oxygenation (ECMO) systems have undergone rapid technological improvements and are now feasible options for medium‐term support of severe cardiac or pulmonary failure. Intractable ventricular arrhythmia is a rare but well‐established indication for heart transplantation. We report a case of persistent ventricular fibrillation (VF) that was rescued by insertion of peripheral veno‐arterial ECMO during cardiopulmonary resuscitation, which provided support for 30 h of continuous VF and subsequently permitted urgent heart transplantation.