In Nordic countries 30-day mortality rate is half that estimated with EuroSCORE II in high-risk adult patients given aprotinin and undergoing mainly complex cardiac procedures

Objectives. To describe current on- (isolated coronary arterty bypass grafting, iCABG) and off-label (non-iCABG) use of aprotinin and associated safety endpoints in adult patients undergoing high-risk cardiac surgery in Nordic countries. Design. Data come from 10 cardiac surgery centres in Finland, Norway and Sweden participating in the European Nordic aprotinin patient registry (NAPaR). Results. 486 patients were given aprotinin between 2016 and 2020. 59 patients (12.1%) underwent iCABG and 427 (87.9%) non-iCABG, including surgery for aortic dissection (16.7%) and endocarditis (36.0%). 89.9% were administered a full aprotinin dosage and 37.0% were re-sternotomies. Dual antiplatelet treatment affected 72.9% of iCABG and 7.0% of non-iCABG patients. 0.6% of patients had anaphylactic reactions associated with aprotinin. 6.4% (95 CI% 4.2%-8.6%) of patients were reoperated for bleeding. Rate of postoperative thromboembolic events, day 1 rise in creatinine >44μmol/L and new dialysis for any reason was 4.7% (95%CI 2.8%-6.6%), 16.7% (95%CI 13.4%-20.0%) and 14.0% (95%CI 10.9%-17.1%), respectively. In-hospital mortality and 30-day mortality was 4.9% (95%CI 2.8%-6.9%) and 6.3% (95%CI 3.7%-7.8%) in all patients versus mean EuroSCORE II 11.4% (95%CI 8.4%-14.0%, p < .01). 30-day mortality in patients undergoing surgery for aortic dissection and endocarditis was 6.2% (95%CI 0.9%-11.4%) and 6.3% (95%CI 2.7%-9.9%) versus mean EuroSCORE II 13.2% (95%CI 6.1%-21.0%, p = .11) and 14.5% (95%CI 12.1%-16.8%, p = .01), respectively. Conclusions. NAPaR data from Nordic countries suggest a favourable safety profile of aprotinin in adult cardiac surgery.

Use and safety of aprotinin in routine clinical practice: A European postauthorisation safety study conducted in patients undergoing cardiac surgery

BACKGROUND

Aprotinin has been used to reduce blood loss and blood product transfusions in patients at high risk of major blood loss during cardiac surgery. Approval by the European Medicines Agency (EMA) for its current indication is limited to patients at high risk of major blood loss undergoing isolated coronary artery bypass graft surgery (iCABG).

OBJECTIVE

To report current real-world data on the use and certain endpoints related to the safety of aprotinin in adult patients.

DESIGN

The Nordic aprotinin patient registry (NAPaR) received data from 83 European centres in a noninterventional, postauthorisation safety study (PASS) performed at the request of the EMA.

SETTING

Cardiac surgical centres committed to enrolling patients in the NAPaR.

PATIENTS

Patients receiving aprotinin agreeing to participate.

INTERVENTION

The decision to administer aprotinin was made by the treating physicians.

MAIN OUTCOME MEASURES

Aprotinin safety endpoints were in-hospital death, thrombo-embolic events (TEEs), specifically stroke, renal impairment, re-exploration for bleeding/tamponade.

RESULTS

From 2016 to 2020, 5309 patients (male 71.5%; >75 years 18.9%) were treated with aprotinin; 1363 (25.7%) underwent iCABG and 3946 (74.3%) another procedure, including a surgical treatment for aortic dissection ( n  = 660, 16.7%); 54.5% of patients received the full-dose regimen. In-hospital mortality in iCABG patients was 1.3% (95% CI, 0.66 to 1.84%) vs. 8.3% (7.21 to 8.91%) in non-iCABG patients; incidence of TEEs and postoperative rise in creatinine level greater than 44 μmol l -1 2.3% (1.48 to 3.07%) and 2.7% (1.79 to 3.49%) vs. 7.2% (6.20 to 7.79%) and 15.5% (13.84 to 16.06%); patients undergoing re-exploration for bleeding 1.4% (0.71 to 1.93%) vs. 3.0% (2.39 to 3.44%). Twelve cases of hypersensitivity/anaphylactic reaction (0.2%) were reported as Adverse Drug Reactions.

CONCLUSION

The data in the NApaR indicated that in this patient population, at high risk of death or blood loss undergoing cardiac surgery, including complex cardiac surgeries other than iCABG, the incidence of adverse events is in line with data from current literature, where aprotinin was not used.

TRIAL REGISTRATION

EU PAS register number: EUPAS11384.

Hypercoagulation Detected by Rotational Thromboelastometry Predicts Mortality in COVID-19: A Risk Model Based on a Prospective Observational Study

Background  Severe disease due to the novel coronavirus disease 2019 (COVID-19) has been shown to be associated with hypercoagulation. The aim of this study was to assess the Rotational Thromboelastometry (ROTEM) as a marker of coagulopathy in hospitalized COVID-19 patients. Methods  This was a prospective, observational study where patients hospitalized due to a COVID-19 infection were eligible for inclusion. Conventional coagulation tests and ROTEM were taken after hospital admission, and patients were followed for 30 days. A prediction model, including variables ROTEM EXTEM-MCF (Maximum Clot Firmness) which in previous data has been suggested a suitable marker of hypercoagulation, age, and respiratory frequency, was developed using logistic regression to evaluate the probability of death. Results  Out of the 141 patients included, 18 (13%) died within 30 days. In the final prediction model, the risk of death within 30 days for a patient hospitalized due to COVID-19 was increased with increased EXTEM-MCF, age, and respiratory frequency. Longitudinal ROTEM data in the severely ill subpopulation showed enhanced hypercoagulation. In an in vitro analysis, no heparin effect on EXTEM-coagulation time (CT) was observed, supporting a severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) effect on prolonged initiation of coagulation. Conclusion  Here, we show that hypercoagulation measured with ROTEM predicts 30-day mortality in COVID-19. Longitudinal ROTEM data strengthen the hypothesis of hypercoagulation as a driver of severe disease in COVID-19. Thus, ROTEM may be a useful tool to assess disease severity in COVID-19 and could potentially guide anticoagulation therapy.

Elimination of CO2 insufflation-induced hypercapnia in open heart surgery using an additional venous reservoir

 

OBJECTIVES

Carbon dioxide (CO2) gas insufflation is used for continuous de-airing during open heart surgery. The aim was to evaluate if an additional separate venous reservoir eliminates CO2 insufflation-induced hypercapnia and keeps sweep gas flow of the oxygenator constant.

METHODS

A separate reservoir was used during cardiopulmonary bypass in addition to a standard venous reservoir. The additional reservoir received drained blood and CO2 gas continuously via a suction drain (1 l/min) and handheld suction devices from the surgical wound. CO2 gas was insufflated via a gas diffuser in the open wound at 10 l/min. In a cross-over design for each patient, gas and blood were either continuously drained from the additional to the standard venous reservoir or not. CO2 pressure in arterial blood (PaCO2) was measured after adjustment of sweep gas flow as necessary and after steady state of PaCO2 was observed. Mean values for each setup (median 4 times) for each patient were analysed with Wilcoxon rank-sum test.

RESULTS

Ten adult patients undergoing open aortic valve replacement were included. Median PaCO2 did not differ between setups (5.41; 5.29-5.57, interquartile range vs 5.41; 5.24-5.58, P = 0.92), whereas sweep gas flow (l/min) was lower (2.58; 2.50-3.16 vs 4.42; 4.0-5.40, P = 0.002) when CO2 gas was not drained from the additional to the standard reservoir.

CONCLUSIONS

An additional venous reservoir for the evacuation of blood from the open surgical wound eliminates CO2 insufflation-induced hypercapnia in open heart surgery keeping PaCO2 and sweep gas flow constant. This prevents possible CO2-induced hyperperfusion of the brain and decreases the risk of cerebral particulate embolization during CO2 insufflation for de-airing in open heart surgery.

CLINICAL TRIAL REGISTRATION

NCT04202575.

IRB APPROVAL DAT AND NUMBER

2018-07-13 and 2018/1091-31.

Rotational thromboelastometry results are associated with care level in COVID-19

High prevalence of thrombotic events in severely ill COVID-19 patients have been reported. Pulmonary embolism as well as microembolization of vital organs may in these individuals be direct causes of death. The identification of patients at high risk of developing thrombosis may lead to targeted, more effective prophylactic treatment. The primary aim of this study was to test whether rotational thromboelastometry (ROTEM) at admission indicates hypercoagulopathy and predicts the disease severity, assessed as care level, in COVID-19 patients. The study was designed as a prospective, observational study where COVID-19 patients over 18 years admitted to hospital were eligible for inclusion. Patients were divided into two groups depending on care level: (1) regular wards or (2) wards with specialized ventilation support. Conventional coagulation tests, blood type and ROTEM were taken at admission. 60 patients were included; age 61 (median), 67% men, many with comorbidities (e.g. hypertension, diabetes). The ROTEM variables Maximum Clot Firmness (EXTEM-/FIBTEM-MCF) were higher in COVID-19 patients compared with in healthy controls (p < 0.001) and higher in severely ill patients compared with in patients at regular wards (p < 0.05). Our results suggest that hypercoagulopathy is present early in patients with mild to moderate disease, and more pronounced in severe COVID-19 pneumonia. Non-O blood types were not overrepresented in COVID-19 positive patients. ROTEM variables showed hypercoagulopathy at admission and this pattern was more pronounced in patients with increased disease severity. If this feature is to be used to predict the risk of thromboembolic complications further studies are warranted.

The MOVEMENT Trial

Background

Morphine administration is a strong predictor of delayed onset of action of orally administered ticagrelor in patients with ST‐segment–elevation myocardial infarction, likely because of impaired gastrointestinal motility. The aim of this study was to evaluate whether the peripheral opioid antagonist methylnaltrexone could improve pharmacodynamics and pharmacokinetics of orally administered ticagrelor in patients with ST‐segment–elevation myocardial infarction receiving morphine.

Methods and Results

The MOVEMENT (Methylnaltrexone to Improve Platelet Inhibition of Ticagrelor in Morphine‐Treated Patients With ST‐Segment Elevation Myocardial Infarction) trial was a multicenter, prospective, randomized, controlled trial in patients with ST‐segment–elevation myocardial infarction treated with morphine and ticagrelor. Upon arrival to the catheterization laboratory, patients were randomized to a blinded intravenous injection of either methylnaltrexone (8 or 12 mg according to weight) or 0.9% sodium chloride. The proportion of patients with high on‐treatment platelet reactivity and plasma concentrations of ticagrelor and AR‐C124910XX were assessed at baseline (arrival in the catheterization laboratory) and 1 and 2 hours later. A total of 82 patients received either methylnaltrexone (n=43) or placebo (n=39). Median (interquartile range) time from ticagrelor administration to randomization was 41 (31–50) versus 45.5 (37–60) minutes (P=0.16). Intravenous methylnaltrexone administration did not significantly affect prevalence of high on‐treatment platelet reactivity at 2 hours after inclusion, the primary end point, when compared with placebo (54% versus 51%, P=0.84). Plasma concentrations of ticagrelor and its active metabolite, the prespecified secondary end points, did not differ significantly between the groups over time. There was no significant difference in patient self‐estimated pain between the groups.

Conclusions

Methylnaltrexone did not significantly improve platelet reactivity or plasma concentrations of orally administered ticagrelor in patients with ST‐segment–elevation myocardial infarction receiving morphine.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02942550.

Carbon dioxide de-airing in minimal invasive cardiac surgery, a new effective device

BACKGROUND

Arterial air embolism during open heart surgery may cause postoperative complications including cerebral injury, myocardial dysfunction, and dysrhythmias. Despite standard de-airing techniques during surgery large amounts of arterial air emboli may still occur, especially during weaning from cardiopulmonary bypass. To prevent this insufflation of carbon dioxide in the wound cavity has been used since the 1950s. The aim of this study was to assess a new mini-diffuser for efficient carbon dioxide de-airing of a minimal invasive cardiothoracic wound cavity model. Up until now no device has been evaluated for this purpose.

METHODS

A new insufflation device, a mini-diffuser, was tested. A thin plastic tube was used as control. The end of the mini-diffuser or the control, respectively, was positioned in a minimal invasive thoracic wound model. Remaining air content was measured during steady state and during intermittent suction with a rough suction device at different carbon dioxide flow rates. Measurements were also carried out in the open surgical wound during minimal invasive aortic surgery in six patients.

RESULTS

The air content was below 1% 4 cm below the surface of the open wound model during continuous carbon dioxide inflow of 2-10 L/min with the mini diffuser. In comparison, carbon dioxide insufflation via the open-ended tube resulted in a mean air content between 10 and 75%. The mean air content of the wound model remained below 1% at a carbon dioxide flow rate of 3-5 L/min during intermittent application of a suction device with a suction rate of 15 L/min. In 6 patients undergoing minimal invasive aortic valve replacement air content in the open surgical wound remained below 1% at a continuous carbon dioxide flow rate of 5 and 8 L/min via the mini-diffuser, respectively.

CONCLUSIONS

The mini diffuser was effective for carbon dioxide de-airing, i.e. < 1% remaining air, of a minimal invasive cardiothoracic wound cavity model with and without intermittent rough suction as well as in patients undergoing minimal invasive aortic valve surgery.

Calculation Algorithm Reduces Protamine Doses Without Increasing Blood Loss or the Transfusion Rate in Cardiac Surgery: Results of a Randomized Controlled Trial

OBJECTIVES

The aim of the study was to investigate whether the HeProCalc algorithm affects heparin and protamine dosage, postoperative blood loss, and transfusion rate.

DESIGN

Randomized controlled trial.

SETTING

University hospital.

PARTICIPANTS

The study comprised 210 cardiac surgery patients undergoing cardiac surgery with cardiopulmonary bypass. Twenty patients were excluded because of re-exploration for localized surgical bleeding (n = 9), violation of protocol (n = 2), aprotinin use (n = 3 and nadir body temperature <32°C (n = 6).

INTERVENTIONS

Study participants were randomly assigned to either traditional heparin and protamine dosage based on body weight only (control group) or dosage based on the HeProCalc algorithm (intervention group).

MEASUREMENTS AND MAIN RESULTS

The initial median heparin dose was 32,500 IU (interquartile range [IQR] 30,000-35,000) in the intervention group compared with 35,000 IU (IQR 30,000-37,500) (p = 0.025) in the control group. The total heparin dose in the intervention group was 40,000 IU (IQR 32,500-47,500) compared with 42,500 IU (IQR 35,000-50,000) in the control group (p = 0.685). The total protamine dose was 210 mg (IQR 190-240) in the intervention group compared with 350 mg (IQR 300-380) (p < 0.001) in the control group. The ratio of total protamine to initial dose of heparin in the intervention group was 0.62 compared with 1.0 (p < 0.001). The amount of chest tube bleeding after 12 postoperative hours was 320 mL (IQR 250-460) in the intervention group compared with 350 mL (IQR 250-450) (p = 0.754) in the control group. Neither the transfusion rate nor postoperative blood loss differed significantly between the 2 groups.

CONCLUSION

Use of the HeProCalc algorithm reduced protamine dosage and the protamine/heparin ratio after cardiopulmonary bypass compared with conventional dosage based on weight without significant effect on postoperative blood loss or the transfusion rate.

Increased visceral tissue perfusion with heated, humidified carbon dioxide insufflation during open abdominal surgery in a rodent model

Tissue perfusion during surgery is important in reducing surgical site infections and promoting healing. This study aimed to determine if insufflation of the open abdomen with heated, humidified (HH) carbon dioxide (CO2) increased visceral tissue perfusion and core body temperature during open abdominal surgery in a rodent model. Using two different rodent models of open abdominal surgery, visceral perfusion and core temperature were measured. Visceral perfusion was investigated using a repeated measures crossover experiment with rodents receiving the same sequence of two alternating treatments: exposure to ambient air (no insufflation) and insufflation with HH CO2. Core body temperature was measured using an independent experimental design with three treatment groups: ambient air, HH CO2 and cold, dry (CD) CO2. Visceral perfusion was measured by laser speckle contrast analysis (LASCA) and core body temperature was measured with a rectal thermometer. Insufflation with HH CO2 into a rodent open abdominal cavity significantly increased visceral tissue perfusion (2.4 perfusion units (PU)/min (95% CI 1.23-3.58); p<0.0001) compared with ambient air, which significantly reduced visceral blood flow (-5.20 PU/min (95% CI -6.83- -3.58); p<0.0001). Insufflation of HH CO2 into the open abdominal cavity significantly increased core body temperature (+1.15 ± 0.14°C) compared with open cavities exposed to ambient air (-0.65 ± 0.52°C; p = 0.037), or cavities insufflated with CD CO2 (-0.73 ± 0.33°C; p = 0.006). Abdominal visceral temperatures also increased with HH CO2 insufflation compared with ambient air or CD CO2, as shown by infrared thermography. This study reports for the first time the use of LASCA to measure visceral perfusion in open abdominal surgery and shows that insufflation of open abdominal cavities with HH CO2 significantly increases visceral tissue perfusion and core body temperature.

Ticagrelor pharmacokinetics and pharmacodynamics in patients with NSTEMI after a 180-mg loading dose

The pharmacokinetics after a 180-mg loading dose (LD) of ticagrelor has not been thoroughly investigated in NSTEMI patients. We aimed to compare the ticagrelor uptake and on-treatment platelet reactivity between non-ST-segment elevation myocardial infarction (NSTEMI) patients and a control group of patients with stable coronary artery disease (SCAD) undergoing elective percutaneous coronary intervention. We performed an observational, prospective, single-center study including 40 NSTEMI patients and 20 SCAD controls. Key exclusion criteria included ongoing opioid treatment. Both groups received a 180-mg ticagrelor LD, and blood samples were taken pre-dose and 1, 2, 3, 4, 5, and 6 hours post-LD. Plasma concentrations of ticagrelor and its active metabolite AR-C124910XX were determined by validated methods. Platelet aggregation was tested using ADP-induced multiple electrode aggregometry. The primary endpoint was the time to maximal ticagrelor concentration (T_max). Clinical trial registration identifier number: NCT02292277. None of the pharmacokinetic variables differed significantly between the groups, including the T_max of ticagrelor (2.0h [1.0-3.0] versus 2.0h [2.0-3.0], p = 0.393) and the active metabolite AR-C124910XX (3.0 [2.0-4.0] versus 3.0 [2.5-4.0], p = 0.289). High on-treatment platelet reactivity (HPR) was defined as > 46 aggregation units and was at one hour seen in 15% of the NSTEMI patients versus 10% of the controls (p = 1.0). At two hours post the 180-mg ticagrelor LD, 3% of the NSTEMI patients had HPR compared with none of the controls (p = 1.0). In conclusion, the uptake of ticagrelor was not significantly slower in NSTEMI patients not receiving opioids compared with the SCAD controls, leading to adequate onset of platelet inhibition in both groups.

Does Coronary Angiography and Percutaneous Coronary Intervention Affect Cognitive Function?

Cerebral microemboli are frequently observed during coronary angiography (CA) and percutaneous coronary intervention (PCI), and their numbers have been related to the vascular access site used. Although cerebral microemboli can cause silent cerebral lesions, their clinical impact is debated. To study this, 93 patients referred for CA or PCI underwent serial cognitive testing using the Montreal Cognitive Assessment (MoCA) test to detect postprocedural cognitive impairment. Patients were randomized to radial or femoral access. In a subgroup of 35 patients, the number of cerebral microemboli was monitored with transcranial Doppler technique. We found the median precatheterization result of the MoCA test to be 27, and it did not change significantly 4 and 31 days, respectively, after the procedure. There was no significant correlation between the number of cerebral microemboli and the difference between preprocedural and postprocedural MoCA tests. The test results did not differ between vascular access sites. One-third of the patients had a precatheterization median MoCA test result <26 corresponding to mild cognitive impairment. In conclusion, using the MoCA test, we could not detect any cognitive impairment after CA or PCI, and no significant correlations were found between the results of the MoCA test and cerebral microemboli or vascular access site, respectively. In patients with suspected coronary heart disease, mild cognitive impairment was common.

An Adjusted Calculation Model Allows for Reduced Protamine Doses without Increasing Blood Loss in Cardiac Surgery

Background Heparin dosage for anticoagulation during cardiopulmonary bypass (CPB) is commonly calculated based on the patient's body weight. The protamine-heparin ratio used for heparin reversal varies widely among institutions (0.7-1.3 mg protamine/100 IU heparin). Excess protamine may impair coagulation. With an empirically developed algorithm, the HeProCalc program, heparin, and protamine doses are calculated during the procedure. The primary aim was to investigate whether HeProCalc-based dosage of heparin could reduce protamine use compared with traditional dosages. The secondary aim was to investigate whether HeProCalc-based dosage of protamine affected postoperative bleeding. Patients and Methods We consecutively randomized 40 patients into two groups. In the control group, traditional heparin and protamine doses, based on body weight alone, were given. In the treatment group, the HeProCalc program was used, which calculated the initial heparin bolus dose from weight, height, and baseline activated clotting time and the protamine dose at termination of CPB. Results We analyzed the results from 37 patients, after exclusion of three patients. Equal doses of heparin were given in both groups, whereas significantly lower mean doses of protamine were given in the treatment group versus control group (211 ± 56 vs. 330 ± 61 mg, p < 0.001). Postoperative bleeding was less in the HeProCalc group (280 ± 229 mL) as compared with the control group (649 ± 279 mL). However, this difference was not found statistically significant (p = 0.074). Conclusion HeProCalc-based dosage of heparin and protamine allowed for reduced protamine use after CPB compared with when conventional calculations were used. Furthermore, HeProCalc-based regimen for heparin reversal suggested less postoperative bleeding, although the difference between the groups was not statistically significant.

Performance and user evaluation of a novel capacitance-based automatic urinometer compared with a manual standard urinometer after elective cardiac surgery

INTRODUCTION

In the intensive care setting, most physiologic parameters are monitored automatically. However, urine output (UO) is still monitored hourly by manually handled urinometers. In this study, we evaluated an automatic urinometer (AU) and compared it with a manual urinometer (MU).

METHODS

This prospective study was carried out in the intensive care unit of a cardiothoracic surgical clinic. In postoperative patients (n = 34) with indwelling urinary catheters and an expected stay of 24 hours or more, hourly UO samples were measured with an AU (Sippi, n = 220; Observe Medical, Gothenburg, Sweden) or an MU (UnoMeter™ 500, n = 188; Unomedical, Birkerød, Denmark) and thereafter validated by cylinder measurements. Malposition of the instrument at the time of reading excluded measurement. Data were analyzed with the Bland-Altman method. The performance of the MU was used as the minimum criterion of acceptance when the AU was evaluated. The loss of precision with the MU due to temporal deviation from fixed hourly measurements was recorded (n = 108). A questionnaire filled out by the ward staff (n = 28) was used to evaluate the ease of use of the AU compared with the MU.

RESULTS

Bland-Altman analysis showed a smaller mean bias for the AU (+1.9 ml) compared with the MU (+5.3 ml) (P <0.0001). There was no statistical difference in measurement precision between the two urinometers, as defined by their limits of agreement (±15.2 ml vs. ±16.6 ml, P = 0.11). The mean temporal variation with the MU was ±7.4 minutes (±12.4%), and the limits of agreement were ±23.9 minutes (±39.8%), compared with no temporal variation with the AU (P <0.0001). The ward staff considered the AU easy to learn to use and rated it higher than the MU (P <0.0001).

CONCLUSIONS

The AU was not inferior to the MU and was significantly better in terms of bias, temporal deviation and staff opinion, although the clinical relevance of these findings may be open to discussion.

Intra-operative tissue oxygen tension is increased by local insufflation of humidified-warm CO2 during open abdominal surgery in a rat model

INTRODUCTION

Maintenance of high tissue oxygenation (PtO2) is recommended during surgery because PtO2 is highly predictive of surgical site infection and colonic anastomotic leakage. However, surgical site perfusion is often sub-optimal, creating an obstructive hurdle for traditional, systemically applied therapies to maintain or increase surgical site PtO2. This research tested the hypothesis that insufflation of humidified-warm CO2 into the abdominal cavity would increase sub-peritoneal PtO2 during open abdominal surgery.

MATERIALS AND METHODS

15 Wistar rats underwent laparotomy under general anesthesia. Three sets of randomized cross-over experiments were conducted in which the abdominal cavity was subjected to alternating exposure to 1) humidified-warm CO2 & ambient air; 2) humidified-warm CO2 & dry-cold CO2; and 3) dry-cold CO2 & ambient air. Sub-peritoneal PtO2 and tissue temperature were measured with a polarographic oxygen probe.

RESULTS

Upon insufflation of humidified-warm CO2, PtO2 increased by 29.8 mmHg (SD 13.3; p<0.001), or 96.6% (SD 51.9), and tissue temperature by 3.0°C (SD 1.7 p<0.001), in comparison with exposure to ambient air. Smaller, but significant, increases in PtO2 were seen in experiments 2 and 3. Tissue temperature decreased upon exposure to dry-cold CO2 compared with ambient air (-1.4°C, SD 0.5, p = 0.001).

CONCLUSIONS

In a rat model, insufflation of humidified-warm CO2 into the abdominal cavity during open abdominal surgery causes an immediate and potentially clinically significant increase in PtO2. The effect is an additive result of the delivery of CO2 and avoidance of evaporative cooling via the delivery of the CO2 gas humidified at body temperature.

Point-of-care testing of clopidogrel-mediated platelet inhibition and risk for cardiovascular events after coronary angiography with or without percutaneous coronary intervention

High-on-treatment platelet reactivity (HPR) during antiplatelet treatment with clopidogrel is associated with increased risk for adverse cardiovascular events after percutaneous coronary intervention (PCI). Recent studies have indicated that the point-of-care platelet function test Plateletworks can predict such events. The objectives were to investigate the incidence of HPR, to identify correlating variables, and to assess if platelet function testing could predict adverse cardiovascular events. Observational, prospective, single-center study of 491 patients on clopidogrel and aspirin who underwent coronary angiography with or without PCI between October 2006 and May 2011. Platelet reactivity was measured with adenosine diphosphate-induced single-platelet function testing (Plateletworks). A cutoff of 82.3% aggregation was established and used to define HPR. Patients were followed for 3 months, and the primary end-point was myocardial infarction. Secondary end-points included stent thrombosis, death, rehospitalization, and a composite of myocardial infarction, death, and stent thrombosis. One hundred and ninety-six of the 491 patients had HPR. This group had a higher BMI (P < 0.001), and had more often received their clopidogrel loading dose within 6-24 h before coronary angiography (P = 0.001). At 3 months follow-up, the event rates of myocardial infarction and rehospitalization, respectively, were higher in HPR patients [5.1 vs. 1.7%, odds ratio (OR) 3.12, 95% confidence interval (CI) 1.05-9.27, P = 0.03; and 23.0 vs. 14.2%, OR 1.80, CI 1.13-2.86, P = 0.01, respectively]. Testing with Plateletworks identified patients at increased risk of myocardial infarction and rehospitalization within 3 months after coronary angiography with or without PCI.

Wound Ventilation With Ultraclean Air for Prevention of Direct Airborne Contamination During Surgery

Background and Objective:

Despite the novelties in operating room ventilation, airborne bacteria remain an important source of surgical wound contamination. An ultraclean airflow from the ceiling downward may convey airborne particles from the surgical team into the wound, thus increasing the risk of infection. Therefore, similar ventilation from the wound upward should be considered. We investigated the effect of wound ventilation on the concentration of airborne particles in a wound model during simulated surgery.

Design:

Randomized experimental study simulating surgery with a wound cavity model.

Setting:

An operating room of a university hospital ventilated with ultraclean air directed downward.

Interventions:

Particles 5 um and larger were counted with and without a 5-cm deep cavity and with and with-out the insufflation of ultraclean air.

Results:

With the surgeon standing upright, no airborne particles could be detected in the wound model. In contrast, during simulated operations, the median number of particles per 0.1 cu ft reached 18 (25th and 75th percentiles, 12 and 22.25) in the model with a cavity and 15.5 (25th and 75th percentiles, 14 and 21.5) without. With a cavity, wound ventilation markedly reduced the median number of particles to 1 (range, 0 to 1.25;P< .001).

Conclusions:

To protect a surgical wound against direct airborne contamination, air should be directed away from the wound rather than toward it. This study provides supportive evidence to earlier studies that operating room ventilation with ultraclean air is imperfect during surgical activity and that wound ventilation may be a simple complement. Further clinical trials are needed.

Correlation between point-of-care platelet function testing and bleeding after coronary angiography according to two different definitions for bleeding

Platelet function testing could be useful when assessing the risk for bleeding during treatment with antiplatelet drugs. This has been indicated in several studies, including the Antiplatelet Therapy for Reduction of Myocardial Damage During Angioplasty-Bleeding (ARMYDA-BLEEDS) study, which demonstrated that testing with a point-of-care assay correlated with bleeding events after percutaneous coronary intervention. To standardize bleeding definitions, the Bleeding Academic Research Consortium (BARC) published a consensus report, which is in need of data-driven validation. Hence, the investigators conducted an observational, prospective, single-center study of 474 patients receiving clopidogrel and aspirin who underwent coronary angiography with or without percutaneous coronary intervention from October 2006 to May 2011. Platelet reactivity was measured with adenosine diphosphate-induced single-platelet function testing (Plateletworks) at the start of coronary angiography. The primary end point was the 30-day incidence of bleeding as defined by BARC and ARMYDA-BLEEDS. The aim of the present study was to investigate the relation between on-treatment platelet reactivity and the 30-day incidence of bleeding complications according to the BARC and ARMYDA-BLEEDS definitions. Patients in the first platelet aggregation quartile had a higher frequency of type 2 or higher BARC bleeding and ARMYDA-BLEEDS-defined bleeding <30 days after coronary angiography compared with the fourth quartile (16.9% vs 6.7%, p = 0.014, and 8.5% vs 1.7%, p = 0.016, respectively) and the third quartile (16.9% vs 7.7%, p = 0.031, and 8.5% vs 2.6%, p = 0.048, respectively). In conclusion, patients with low on-treatment platelet reactivity at the time of intervention had a significantly higher incidence of bleeding according to the BARC and ARMYDA-BLEEDS definitions <30 days after coronary angiography with or without percutaneous coronary intervention.

Adenosine diphosphate-induced single-platelet count aggregation and bleeding in clopidogrel-treated patients undergoing coronary artery bypass grafting

OBJECTIVES

To investigate the association between adenosine diphosphate (ADP)-induced platelet aggregation measured by single-platelet count testing and postoperative blood loss in clopidogrel-treated patients with acute coronary syndromes undergoing coronary artery bypass grafting (CABG).

DESIGN

Prospective observational study.

SETTING

Clinical study in one cardiac surgery center.

PARTICIPANTS

Eighty-eight patients treated with clopidogrel (300-600 mg loading dose followed by 75 mg daily) within 7 days before CABG.

INTERVENTIONS

Platelet function was assessed preoperatively by single-platelet count ADP-induced platelet aggregation. Postoperative blood loss and transfusion requirements were recorded.

MEASUREMENTS AND MAIN RESULTS

There was no significant association between ADP-induced platelet aggregation and blood loss 12 hours postoperatively (estimate -7.51; 95% confidence interval [CI]: -16.9-1.9; p = 0.12). ADP-induced platelet aggregation was associated significantly with the number of platelet concentrates administered within 24 hours after surgery (incidence rate ratio [IRR] 0.95; 95% CI: 0.92-0.98; p<0.01), but not to the number of packed red blood cells (IRR 0.98; 95% CI: 0.95-1.01; p = 0.14).

CONCLUSIONS

Preoperative ADP-induced platelet aggregation measured by single-platelet count testing in clopidogrel-treated patients with acute coronary syndromes undergoing CABG was not associated with postoperative blood loss or packed red blood cells transfused, but was associated significantly with number of platelet concentrates administered during the initial 24 postoperative hours.

Guidewire withdrawal in ascending aorta increases cerebral microembolism during coronary angiography: a randomized comparison of two guidewire techniques

BACKGROUND

Microemboli are frequently detected entering the middle cerebral arteries during coronary angiography (CA). Recent studies have reported that cerebral microemboli, especially particulate cerebral microemboli, may cause silent ischemic cerebral lesions.

AIMS

To investigate whether the occurrence of particulate cerebral microemboli during diagnostic CA is influenced by which guidewire technique is used.

METHODS

Patients with stable angina pectoris or non-ST elevation acute coronary syndrome, referred for CA, were randomized to initial advancement of catheters with a leading guidewire over the aortic arch or to initial guidewire withdrawal in the descending aorta with advancement of catheters alone. After completed CA (part 1), new catheters and guidewires were advanced with guidewire technique contrary to the one first used (part 2). Patients were continuously monitored with transcranial Doppler (TCD), and cerebral microemboli were automatically counted and differentiated.

RESULTS

Statistical analysis was performed on 41 patients. The results in part 1 were confirmed in part 2. The median number (interquartile range) of particulate cerebral microemboli was significantly higher when catheters were advanced with, compared to without, a guidewire over the aortic arch; overall, 6 (IQR, 1-9) vs 1 (IQR, 0-3); P=.01.

CONCLUSIONS

Advancement of catheters with a leading guidewire over the aortic arch with subsequent flushing in the ascending aorta consistently generated more particulate cerebral microemboli, implying that the choice of guidewire technique has an impact on the risk for cerebral lesions during CA.

Myocardial recovery in peri-partum cardiomyopathy after continuous flow left ventricular assist device

Left ventricular assist devices (LVADs) offer effective therapy for severe heart failure (HF) as bridge to transplantation or destination therapy. Rarely, the sustained unloading provided by the LVAD has led to cardiac reverse remodelling and recovery, permitting explantation of the device. We describe the clinical course of a patient with severe peri-partum cardiomyopathy (PPCM) rescued with a continuous flow LVAD, who experienced recovery and explantation. We discuss assessment of and criteria for recovery.

Cerebral Microembolism During Coronary Angiography

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.

Aprotinin reduces the antiplatelet effect of clopidogrel

Aprotinin reduces bleeding and transfusion rates in patients undergoing coronary surgery while on clopidogrel. However, safety studies have indicated that aprotinin may have a possible adverse effect related to an increased incidence of thromboembolic events. We therefore studied the adenosinediphosphate (ADP) mediated platelet aggregation before and after administration of aprotinin in patients on clopidogrel. Fifteen clopidogrel-treated patients with acute coronary syndrome undergoing coronary surgery were studied. ADP-mediated platelet aggregation and platelet count ratio (%) were measured before and after a bolus dose [2 x 10(6) kallikrein inhibiting units (KIU)] of aprotinin. Aprotinin induced an increased aggregation in 11 of 15 patients (73%), and a decrease was registered in two patients (13%). The median (25th/75th percentile) ADP-mediated platelet aggregation before and after aprotinin was 84% (76/91) and 94% (86/97, P<0.01). Clopidogrel non-responders with >90% aggregation (n=4) had a median aggregation of 94.5% (91.5/97.5) vs. 82% (73/87, P<0.01) in the responders (n=11). The median increase in platelet aggregation after aprotinin was 8% (5/20) in the responders vs. 0% (-5.25/3, P<0.01) in the non-responders. Aprotinin increased ADP induced platelet aggregation from 84 to 94% in patients on clopidogrel, which corresponds to a median decrease in relative platelet inhibition of >50%.

Novel antithrombotic agents and the risk of bleeding

Many coronary patients on antiplatelet (PLT) drugs require coronary artery bypass grafting surgery under conditions that may not allow sufficient time for or warrant discontinuation of anti-PLT treatment. Recent clinical data show that intraoperative aprotinin significantly reduces postoperative bleeding and transfusion requirements in this patient population. If surgical bleeding persists, the administration of Factor VIIa should be considered.

A policy to reduce stroke in patients with extensive atherosclerosis of the ascending aorta undergoing coronary surgery

Since 1995 we have routinely used epiaortic scanning in cardiac surgery and since 1998 we have employed off-pump surgery for coronary revascularization. In patients with extensive atherosclerosis in the ascending aorta we tried to assess whether or not conversion from a planned on-pump to off-pump coronary surgery affects the incidence of postoperative stroke. We studied 28 consecutive patients with extensive atherosclerosis in the ascending aorta undergoing coronary surgery. Extensive atherosclerosis, detected by epiaortic ultrasound, was defined as involvement of 6 or more out of 12 segments. Since 1998 we have converted 15 patients with extensive atherosclerosis in the ascending aorta from on-pump to off-pump. Thirteen patients with similar disease who underwent on-pump before the introduction of off-pump were used as controls. The incidence of stroke in the off-pump group was 0% as compared with 31% in the coronary artery bypass grafting group (P=0.03). Y-grafts were used more often in the off-pump (47%) than in the on-pump group (0%, P<0.01). The non-touch technique of the ascending aorta was also more frequently used in the off-pump group (73 versus 0%, P<0.001). Off-pump reduces the incidence of stroke in patients with aortic atherosclerosis when the disease occupies 50% or more of the ascending aorta.

The topography of aortic atherosclerosis enhances its precision as a predictor of stroke

BACKGROUND

Atherosclerosis of the thoracic aorta is an independent risk factor for stroke after cardiac surgery. No attention had so far been paid to its topography. The relationship between the topography of aortic atherosclerosis and stroke was studied in patients admitted for coronary surgery.

METHODS

The extent and location of atherosclerosis in the ascending aorta and arch was assessed intraoperatively with epiaortic ultrasound and transesophageal echocardiography in 611 consecutive patients. They were followed for 5.5 +/- 1.7 years (mean +/- SE), amounting to 3,358 patient-years.

RESULTS

The incidence of early postoperative (<30-day) stroke was 6.4% in patients with atherosclerosis of the ascending aorta and 1.5% in those without (p = 0.004). The five-year stroke-free survival rates (>30 days after the operation) for patients without aortic disease, with less than 50%, and with greater than 50% of the ascending aorta affected, were 95.3 +/- 0.9%, 91.8 +/- 2.1%, and 65.0 +/- 14.6%, respectively (p < 0.0001).

CONCLUSIONS

Atherosclerosis of the ascending aorta stands out as a predictor of late stroke. High risk is predominantly linked to atheromas in its distal part and lesser curvature.

Pre-operative mild cognitive dysfunction predicts risk for post-operative delirium after elective cardiac surgery

BACKGROUND AND AIMS

To identify pre-operative risk factors for delirium in patients undergoing elective cardiac surgery, using clearly defined diagnostic criteria for delirium, and a thorough clinical assessment.

METHODS

The incidence of post-operative delirium in 107 patients >or=60 years undergoing elective cardiac surgery was calculated. None of the patients included suffered from dementia. Pre-operative cognitive function in all patients was assessed using the Mini Mental State Examination (MMSE) and post-operative delirium was diagnosed using the Confusion Assessment Method (CAM). Post-operative clinical and cognitive assessments were carried out for all patients.

RESULTS

Twenty-five patients (23.4%) developed delirium post-operatively. Clinical parameters, including age, gender, co-morbidities, medications, and peri-operative parameters, were similar in patients with and without post-operative delirium. Patients with pre-operative subjective memory complaints and lower MMSE scores, undergoing valve operation or valve + coronary artery bypass grafting (CABG), exhibited an increased risk of developing post-operative delirium. Additionally, delirious patients had a significant decline in post-operative MMSE score compared with the non-delirious ones.

CONCLUSIONS

The main pre-operative risk factors for post-operative delirium after elective cardiac operations were subjective memory complaints, mild cognitive impairment, and type of cardiac surgery, such as valve procedures. This study suggests that cognitive evaluation should be included in pre-operative assessment.