Carbon Dioxide Flush of an Integrated Minimized Perfusion Circuit Prior to Priming Prevents Spontaneous Air Release Into the Arterial Line During Clinical Use.

Recently, an oxygenator with an integrated centrifugal blood pump (IP) was designed to minimize priming volume and to reduce blood foreign surface contact even further. The use of this oxygenator with or without integrated arterial filter was compared with a conventional oxygenator and nonintegrated centrifugal pump. To compare the air removal characteristics 60 patients undergoing coronary artery bypass grafting were alternately assigned into one of three groups to be perfused with a minimized extracorporeal circuit either with the conventional oxygenator, the oxygenator with IP, or the oxygenator with IP plus integrated arterial filter (IAF). Air entering and leaving the three devices was measured accurately with a bubble counter during cardiopulmonary bypass. No significant differences between all groups were detected, considering air entering the devices. Our major finding was that in both integrated devices groups incidental spontaneous release of air into the arterial line in approximately 40% of the patients was observed. Here, detectable bolus air (>500 µm) was shown in the arterial line, whereas in the minimal extracorporeal circulation circuit (MECC) group this phenomenon was not present. We decided to conduct an amendment of the initial design with METC-approval. Ten patients were assigned to be perfused with an oxygenator with IP and IAF. Importantly, the integrated perfusion systems used in these patients were flushed with carbon dioxide (CO2 ) prior to priming of the systems. In the group with CO2 flush no spontaneous air release was observed in all cases and this was significantly different from the initial study with the group with the integrated device and IAF. This suggests that air spilling may be caused by residual air in the integrated device. In conclusion, integration of a blood pump may cause spontaneous release of large air bubbles (>500 µm) into the arterial line, despite the presence of an integrated arterial filter. CO2 flushing of an integrated cardiopulmonary bypass system prior to priming may prevent spontaneous air release and is strongly recommended to secure patient safety.

Diagnostic Accuracy of an Algorithm for Discriminating Presumed Solid and Gaseous Microembolic Signals During Transcranial Doppler Examinations.

OBJECTIVE: The aim of the work described here was to assess the diagnostic accuracy of a new algorithm (SGA-a) for time-domain analysis of transcranial Doppler audio signals to discriminate presumed solid and gaseous microembolic signals and artifacts (SGAs). METHODS: SGA-a was validated by human experts in an artifact cohort of 20 patients subjected to a 1-h transcranial Doppler exam before cardiac surgery (cohort 1). Emboli were validated in a cohort of 10 patients after aortic valve replacement in a 4-h monitoring period (cohort 2). The SGA misclassification rate was estimated by testing SGA-a on artifact-free test files of solid and gaseous emboli. RESULTS: In cohort 1 (n = 24,429), artifacts were classified with an accuracy of 94.5%. In cohort 2 (n = 12,328), the accuracy in discriminating solid/gaseous emboli from artifacts was 85.6%. The 95% limits of agreement for, respectively, the numbers of presumed solids and gaseous emboli, artifacts and microembolic signals of undetermined origin were [-10, 10], [-14, 7] and [-9, 16], and the intra-class correction coefficients were 0.99, 0.99 and 0.99, respectively. The rate of misclassification of solid test files was 2%, and the rate of misclassification of gaseous test files was 12%. CONCLUSION: SGA-a can detect presumed solid and gaseous microembolic signals and differentiate them from artifacts. SGA-a could be of value when both solid and gaseous emboli may jeopardize brain function such as seen during cardiac valve and/or aortic arch replacement procedures.

Safety and effectiveness of selective carotid angioplasty prior to cardiac surgery: a single-centre matched case-control study.

OBJECTIVES: Reducing the rate of postoperative stroke after cardiac surgery remains challenging, especially in patients with occlusive cerebrovascular disease. Angioplasty in all patients with high-grade carotid artery stenosis has not been shown to be effective in reducing the post-surgical stroke rate. In this study, we present the initial results of a different approach using selective carotid angioplasty only in patients with poor intracranial collaterals. METHODS: We conducted a single-centre study to assess the safety of this procedure. The postangioplasty complication rate of the study group was compared to that of patients who were scheduled for symptomatic carotid artery angioplasty. To determine the effectiveness of this procedure, the post-cardiac surgery complication rate of the study group was compared with that of the matched case controls. RESULTS: Twenty-two patients were treated with selective carotid angioplasty without developing persistent major neurological complications. All patients except 1 patient subsequently underwent surgery without developing persistent major neurological disabilities. Two patients died of cardiogenic shock within 30 days. CONCLUSIONS: Selective carotid angioplasty prior to cardiac surgery in patients with a presumed high risk of stroke was relatively safe and effective in this study group. Although this strategy does not prevent stroke in these high-risk patients, data suggest that this approach shifts the postoperative type of stroke from a severe haemodynamic stroke towards a minor embolic stroke with favourable neurological outcomes. Larger studies are needed to determine whether this strategy can effectively eliminate the occurrence of haemodynamic stroke after cardiac surgery.

Impact of the Haga Braincare Strategy on the burden of haemodynamic and embolic strokes related to cardiac surgery.

OBJECTIVES: This study prospectively evaluates the impact of the Haga Braincare Strategy (HBS) on the occurrence of haemodynamic and embolic stroke in a cohort of patients who underwent coronay artery bypass grafting (CABG), valve replacement of a combination of both types of surgery between 2012 and 2015 at the Haga Teaching Hospitals. METHODS: The HBS is a dual strategy based on a preoperative vascular work-up of the cerebral circulation by transcranial Doppler and a perioperative monitoring of the cerebral circulation by cerebral oximetry. Duplex of the carotid arteries and/or computed tomography angiography prior to surgery was performed in high-risk patients. Patients with severe carotid artery stenosis were scheduled for carotid angioplasty prior to surgery or waived from surgery. RESULTS: A total of 1065 patients were included. Poor cerebral haemodynamics were identified by transcranial Doppler in 2.1% of patients (n = 22). Based on the HBS, 3 patients were waived from surgery, 4 received preoperative carotid angioplasty followed by cardiac surgery and the remaining patients were operated while being monitored with bilateral cerebral oximetry sensors. In all, 2.2% of the study group experienced a stroke (n = 23), of which none were classified as haemodynamic. Most of the remaining presumed embolic strokes showed a minor to moderate stroke severity. CONCLUSIONS: In this single-centre prospective follow-up study, surveillance of cerebral perfusion by the HBS eliminated the occurrence of haemodynamic stroke while most of the residual strokes had a good to favourable prognosis.

Long-term results of reoperation for left atrioventricular valve regurgitation after correction of atrioventricular septal defects.

BACKGROUND: Long-term results of reoperation for left atrioventricular valve regurgitation (LAVVR) after previous correction of atrioventricular septal defect (AVSD) are scarce. We evaluated long-term outcome of reoperation for LAVVR and identified risk factors for reoperation. METHODS: Between December 1976 and July 2006, 45 of 312 patients with correction of different AVSDs underwent reoperation for LAVVR. The cohort of 267 patients who did not need reoperation for LAVVR allowed for the identification of risk factors for reoperation and evaluation of overall survival after primary AVSD repair in a competing risk scenario. Clinical data were obtained by retrospective review. RESULTS: The left atrioventricular valve (LAVV) was repaired in 31 patients (68.9%) and replaced in 14 (31.1%). There were 3 in-hospital deaths (6.7%) and 2 late deaths (4.4%). Estimated overall survival was 88.1% at 15 years after the reoperation, and estimated incidence of death after reoperation in the total patient cohort was 2% at 15 years after the primary AVSD repair. Overall survival was significantly higher after LAVV repair than after replacement (p=0.010). Ten patients with LAVV repair required a second reoperation for LAVVR. At follow-up, survivors were in New York Heart Association functional class I (n=36) or II (n=4). Independent risk factors for first reoperation for LAVVR were associated cardiovascular anomalies (p<0.001), LAVV dysplasia (p<0.001), and nonclosure of the cleft (p=0.027). CONCLUSIONS: After previous correction of AVSD, LAVVR can usually be corrected by valve repair. A very dysplastic valve may necessitate replacement. Overall survival is higher after repair than after replacement. In general, overall survival of patients reoperated on for LAVVR is favorable. The overall mortality rate after primary repair of AVSD is explained only for a small part by mortality after reoperation for LAVVR.

More than 30 years' experience with surgical correction of atrioventricular septal defects.

BACKGROUND: Outcome of surgical correction of atrioventricular septal defects (AVSD) still varies despite enhanced results. We reviewed our 30-year experience with AVSD repair and identified risk factors for mortality and reoperation. METHODS: Between 1975 and 2006, 312 patients underwent surgery for complete AVSD (n = 209; 67.0%), partial AVSD (n = 76; 24.4%), or intermediate AVSD (n = 27; 8.6%). Mean age was 2.4 ± 3.9 years; 142 patients (45.5%) were younger than 6 months. Follow-up was 99.0% complete. RESULTS: There were 26 in-hospital deaths (8.3%) and 6 late deaths (2.1% of 283). Estimated overall survival for the total study population was 91.3%, 90.6%, and 88.6% at 1, 5, and 15 years, respectively. In the multivariable logistic regression analysis, surgical era 1975 to 1995 (p < 0.001) and younger age (p = 0.004) were found to be independent risk factors for early mortality, whereas preoperative AV valve insufficiency showed a tendency toward statistical significance (p = 0.052). Of the hospital survivors, 43 patients required a late reoperation. Estimated freedom from late reoperation was 96.4%, 89.3%, and 81.8% at 1, 5, and 15 years, respectively. Multivariable Cox regression analysis showed associated cardiovascular anomalies (p < 0.001), left AV valve dysplasia (p < 0.001), and absence of cleft closure (p = 0.003) to be independent risk factors for late reoperation. CONCLUSIONS: AVSD repair can be accomplished with good long-term results. Early surgical era, associated cardiovascular anomalies, left AV valve dysplasia, and absence of cleft closure negatively influence survival and risk of reoperation.

Results of surgical repair of atrioventricular septal defect with double-orifice left atrioventricular valve.

OBJECTIVE: The outcome of surgical correction of atrioventricular septal defect with double-orifice left atrioventricular valve has improved in recent years but is still reported to be associated with high mortality and reoperation rates. Controversy exists about the management of the accessory orifice. We evaluated our results with correction of atrioventricular septal defect with double-orifice left atrioventricular valve. METHODS: Between 1975 and 2006, 21 patients underwent correction of atrioventricular septal defect with double-orifice left atrioventricular valve. Clinical data were obtained by means of retrospectively reviewing inpatient and outpatient medical records. To evaluate the influence of double-orifice left atrioventricular valve on mortality and the need for reoperation, a comparison was made with 291 consecutive patients who, during the same period, underwent correction of atrioventricular septal defect without double-orifice left atrioventricular valve. RESULTS: None of the 21 patients with double-orifice left atrioventricular valve had undergone a previous operation. The accessory orifice was managed with different techniques depending on the severity of the regurgitation. There was no in-hospital mortality, and there were 3 late deaths. Seven patients required 12 reoperations, 7 for left atrioventricular valve insufficiency. Double-orifice left atrioventricular valve had no influence on mortality but was a significant predictor for reoperation compared with repair of atrioventricular septal defect without double-orifice left atrioventricular valve. At the latest follow-up, all 18 survivors were in New York Heart Association functional class capital I, Ukrainian without medication. Only 1 patient showed residual mild left atrioventricular valve insufficiency. CONCLUSION: Atrioventricular septal defect with double-orifice left atrioventricular valve can be repaired with low mortality. However, double-orifice left atrioventricular valve is a predictor for reoperation. The accessory orifice is often competent and should then be left untouched. If regurgitation of the accessory orifice is present, this is best managed with suture or patch closure.

28 years' experience with transatrial-transpulmonary repair of atrioventricular septal defect with tetralogy of Fallot.

BACKGROUND: The outcome of surgical correction of atrioventricular septal defect and tetralogy of Fallot has improved in recent years but is still reported to be associated with high mortality. Controversy exists about the need of a right ventriculotomy or a right ventricular to pulmonary artery conduit. The purpose of this study was to evaluate our results of atrioventricular septal defect and tetralogy of Fallot repair by transatrial-transpulmonary approaches. METHODS: Between 1979 and 2007, 20 consecutive patients underwent correction of atrioventricular septal defect and tetralogy of Fallot. Five patients had undergone prior palliative shunts. In all patients, a transatrial-transpulmonary approach was used and repair was accomplished without a conduit. The two-patch technique was used to correct the atrioventricular septal defect. Clinical data were obtained by retrospective review of inpatient and outpatient clinical charts. RESULTS: There was no in-hospital mortality and one late, noncardiac death. Six patients required eight reoperations, six for left atrioventricular valve insufficiency (repair: n = 4; replacement: n = 2), one for residual ventricular septal defect, and one for pulmonary artery branch obstruction. Follow-up was complete for all patients (median, 17 years; range, 1.5 to 28 years). All 19 survivors were in good clinical condition at last control, without medication, and in New York Heart Association class I (n = 18) or II (n = 1). Transesophageal echocardiography revealed good right ventricular function, low right ventricular outflow tract gradients (mean, 9 +/- 7.4 mm Hg), and trace pulmonary valve insufficiency (n = 11). CONCLUSIONS: Atrioventricular septal defect and tetralogy of Fallot can be repaired with low mortality by the transatrial-transpulmonary approach without the use of a conduit.