Frans G. Waanders

Mini extracorporeal circuit for coronary artery bypass grafting: initial clinical and biochemical results: a comparison with conventional and off-pump coronary artery bypass grafts concerning global oxidative stress and alveolar function.

Background: The new concept of mini-extracorporeal circulation (MECC) for coronary artery bypass grafts (MCABG) consists of minimal priming volume, a heparin-coated closed circuit, a centrifugal pump, active drainage, blood cardioplegia and a cell-saving device. The potential organ protective effect of this technique during CABG is unknown. Initial clinical outcomes, oxidative stress, alveolar shunting and need for blood transfusion were investigated for MCABG patients. Subsets of these data were compared to outcomes of matched groups of patients operated conventionally (CCABG) and off-pump (OPCAB). Methods: Data of 184 patients were gathered and analysed from a prospective observational database system. This database consists of the initial experience with the first 114 MCABG operations. Of these, the clinical outcome was investigated. In a subset of 60 MCABGs, need for transfusion was monitored and compared to 60 CCABGs. Serum concentrations of malondialdehyde (MDA), allantoin/urate ratios, shunt fractions and lung epithelium-specific proteins (CC16) were measured as biomarkers of damage during MCABG, CCABG and OPCAB (n-30). Results: Patient groups were similar concerning age, risk and number of distal anastomoses. Clinical outcomes are shown for MCABGs only. During MCABG, need for trans-fusion was significantly reduced compared to CCABG (pB/0.001). Serum concentrations of MDA and allantoin/urate ratios showed significantly reduced oxidative stress during MCABG compared to CCABG. During MCABG, F-shunts were reduced shortly after surgery. Increased concentrations of pneumoprotein CC16 were measured during CCABG compared to MCABG (data submitted). Conclusion: Short-term clinical outcomes of MCABG patients are satisfactory. Compared to CCABG the need for transfusion is significantly reduced when a MECC is used. Oxidative stress parameters show a tendency towards improved global organ protection compared to CCABG. F-shunt fractions and CC16 concentrations suggest reduced alveolar damage during MCABG. In a prospective study, the protective effect of mini-CABG has to be confirmed.

Mini extracorporeal circuit for coronary artery bypass grafting: initial clinical and biochemical results

Background: The new concept of mini-extracorporeal circulation (MECC) for coronary artery bypass grafts (MCABG) consists of minimal priming volume, a heparin-coated closed circuit, a centrifugal pump, active drainage, blood cardioplegia and a cell-saving device. The potential organ protective effect of this technique during CABG is unknown. Initial clinical outcomes, oxidative stress, alveolar shunting and need for blood transfusion were investigated for MCABG patients. Subsets of these data were compared to outcomes of matched groups of patients operated conventionally (CCABG) and off-pump (OPCAB). Methods: Data of 184 patients were gathered and analysed from a prospective observational database system. This database consists of the initial experience with the first 114 MCABG operations. Of these, the clinical outcome was investigated. In a subset of 60 MCABGs, need for transfusion was monitored and compared to 60 CCABGs. Serum concentrations of malondialdehyde (MDA), allantoin/urate ratios, shunt fractions and lung epithelium-specific proteins (CC16) were measured as biomarkers of damage during MCABG, CCABG and OPCAB (n-30). Results: Patient groups were similar concerning age, risk and number of distal anastomoses. Clinical outcomes are shown for MCABGs only. During MCABG, need for trans-fusion was significantly reduced compared to CCABG (pB/0.001). Serum concentrations of MDA and allantoin/urate ratios showed significantly reduced oxidative stress during MCABG compared to CCABG. During MCABG, F-shunts were reduced shortly after surgery. Increased concentrations of pneumoprotein CC16 were measured during CCABG compared to MCABG (data submitted). Conclusion: Short-term clinical outcomes of MCABG patients are satisfactory. Compared to CCABG the need for transfusion is significantly reduced when a MECC is used. Oxidative stress parameters show a tendency towards improved global organ protection compared to CCABG. F-shunt fractions and CC16 concentrations suggest reduced alveolar damage during MCABG. In a prospective study, the protective effect of mini-CABG has to be confirmed.

Is Extended Arch Replacement for Acute Type A Aortic Dissection an Additional Risk Factor for Mortality

BACKGROUND We report our experience with surgery for acute type A aortic dissection with involvement of the aortic arch. METHODS From January 1986 to December 2001, 277 patients underwent surgery for acute type A aortic dissection. In 70 patients (25.3%), surgery was extended into the aortic arch: hemiarch and total arch replacement in 53 (75.7%) and 17 (24.3%) patients, respectively. Deep hypothermic circulatory arrest was used in 19 patients, antegrade selective cerebral perfusion in 38, and combined deep hypothermic circulatory arrest with antegrade selective cerebral perfusion in 13. RESULTS Operative mortality was 18.6% (13/70) after extended replacement into the arch versus 21.7% (45/207) after surgery limited to the ascending aorta (p = 0.62). Multivariate analysis did not reveal significant risk factors for operative mortality. Postoperatively, 5 patients (8.1%) had a new postoperative cerebral vascular accident (CVA). Multivariate analysis showed an earlier date of operation as the only independent determinant for a new postoperative CVA (p = 0.0162, RR = 0.80/year, 95% CI = 0.67 to 0.96). None of the patients, operated on with antegrade selective cerebral perfusion, had a new cerebral deficit. Comparing the different methods of cerebral protection, multivariate risk analysis revealed antegrade selective cerebral perfusion as a significant protective factor against new postoperative CVA (p = 0.0110, OR = 0.12, 95% CI = 0.02 to 0.61). Survival at 5 and 10 years was 66.6.5% and 40.0%, respectively, after replacement of the aortic arch versus 68.7% and 57.7%, respectively, after replacement of the ascending aorta (p = 0.96). Freedom from aortic arch reoperation was 96.3% at 5 and 77.0% at 10 years versus 86.6% and 75.1% in both groups, respectively (p = 0.21). CONCLUSIONS Extended replacement into the aortic arch during surgery for acute type A dissection does not influence early and late results. The best cerebral protection seems to be obtained with antegrade selective cerebral perfusion.

Bilateral antegrade selective cerebral perfusion during surgery on the proximal thoracic aorta

OBJECTIVE To assess risk factors for hospital death and neurologic outcome after surgery on the proximal thoracic aorta using moderate hypothermic circulatory arrest and bilateral antegrade selective cerebral perfusion. METHODS From October 1995 through June 1999, 163 patients with a mean age of 63+/-11 years underwent surgery using bilateral antegrade selective cerebral perfusion. Degenerative aneurysms (55%) and acute type A dissection (28%) were the predominant indications for operation. Forty-six (28%) operations were considered as emergency procedure. Twenty-four (15%) procedures were reoperations. RESULTS Mean ASCP time was 48+/-20 min. Hospital mortality was 8.6% (n=14; 70% confidence limit (CL): 6.4-10.8%). Univariate risk factors for hospital mortality were acute type A dissection (P=0.003), central neurologic damage <24 h before the operation (P=0.000), preoperative hemodynamic instability (P=0.034), and rethoracotomy for any cause (P=0.036). Logistic regression analysis identified central neurologic damage <24 h (P=0.006, odds ratio 14) as an independent risk factor. Temporary neurologic damage occurred in 3.8% (n=6; 70% CL: 2.3-5.3%) of patients. Logistic regression analysis indicated preoperative hemodynamic instability (P=0.003, odds ratio 13) as an independent risk factor. Perioperative permanent central neurologic damage was reported in another 3.8% (n=6; 70% CL: 2.3-5.3%) patients. Acute type A dissection (P=0.018, odds ratio 8) and the non-use of a midline sternotomy (P=0.049, odds ratio 8) were retained as independent risk factors. CONCLUSION Hospital mortality and perioperative neurologic complications are not significantly influenced by the duration of antegrade selective cerebral perfusion. Overall complication rate is low.

Myocardial oxidative stress, and cell injury comparing three different techniques for coronary artery bypass grafting

OBJECTIVE Oxidative stress as a result of reperfusion injury is a known causative factor of cardiac muscle injury. In the peripheral blood as well in the coronary sinus, oxidative stress parameters and cardiac biomarkers were measured to investigate the different levels of oxidative stress during three different CABG techniques; MCABG (with minimal prime volume and warm blood cardioplegia) that was newly introduced in our hospital, versus OPCAB, versus our current standard, conventional CABG (CCABG, consisting of high volume prime and cold crystalloid cardioplegia). Concomitantly, cardiac biomarkers were measured to detect myocardial cell injury. METHODS Thirty patients scheduled for CABG with the intention to treat three-vessel disease were randomly assigned for CCABG, MCABG or OPCAB. Perioperatively, plasma levels of malondialdehyde (MDA) as a marker of oxidative stress, and the allantoin/uric acid ratio (A/U ratio) as a marker of antioxidant activity were measured in the ascending aorta (Aa), and in the coronary sinus (Cs), simultaneously. Additionally peripheral (Aa) blood levels of heart fatty acid binding protein (HFABP), troponin T, CPK and CKMB as markers of myocardial injury were obtained. RESULTS The MCABG group had significantly lower MDA levels in the Cs compared to the CCABG group, respectively, to the OPCAB group (p=0.04 and p=0.03). At all time points the A/U ratio in the CCABG group remained significantly higher in the Cs as well in the Aa samples compared to the MCABG and the OPCAB group (p<0.001, respectively, p<0.001, for both groups). HFABP and troponin T showed consistent curves compared to the CPK figure over time in all groups. CONCLUSION In this study coronary sinus blood levels of oxidative stress parameters were consistently higher compared to peripheral blood levels. The levels were lowest in the MCABG study group. In this group also the lowest levels cardiac biomarkers of myocardial injury were found.

Operative risk factors of type A aortic dissection: analysis of 252 consecutive patients

OBJECTIVE We examined operative risk factors for postoperative death after surgery for acute type A aortic dissection. METHODS Between 1974 and 1999, 252 patients, 163 men and 89 women (mean+/-SD age, 58+/-12 years) underwent surgery for acute type A aortic dissection. Fifty-eight (23.0%) were in cardiogenic shock at time of surgery. Most patients underwent ascending aorta replacement which was combined with aortic valve replacement by means of a composite graft in 30 (11.9%) patients and an isolated aortic valve replacement in 16 (6.3%) patients. RESULTS The overall operative mortality rate was 25.0% (n=63); 27.0% for patients operated upon with aortic cross-clamping, 23.7% after deep hypotherm circulatory arrest and 23.3% after antegrade selective cerebral perfusion (ASCP) (p=0.73). Multivariate analysis revealed iatrogenic dissection (p=0.0096, odds ratio=5.7), preoperative cardiopulmonary resuscitation (p=0.0095, odds ratio=5.5) and every quarter of an hour longer extracorporeal circulation (p=0.049, odds ratio=1.1) as independent risk factors for operative mortality. Aortic valve replacement or Bentall procedure (p=0.0185, odds ratio=0.3) were protective factors. There were 44 new postoperative strokes: 4.7% in the group operated upon with and 20.1% in the group without ASCP (p=0.01). CONCLUSION In order to avoid cardiogenic shock and preoperative cardiopulmonary resuscitation, patients with acute type A aortic dissection should be treated promptly. The choice to use an aortic valve prosthesis or Bentall procedure when applicable seems to benefit the postoperative early survival. The risk of new postoperative neurological events might be reduced by avoiding the appliance of an aortic cross-clamp and by using ASCP.

Combined coronary artery bypass grafting and aortic valve replacement with minimal extracorporeal closed circuit circulation versus standard cardiopulmonary bypass

Isolated aortic valve replacement (AVR) or coronary artery bypass grafting (CABG) using minimized extracorporeal circulation (MECC) has been shown to have less deleterious effects than standard cardiopulmonary bypass (CPB). In this prospective cohort study, we evaluated and compared clinical results of combined AVR with CABG using MECC. We prospectively collected preoperative, intraoperative, postoperative and follow-up data of 65 patients who underwent combined AVR with CABG using MECC and compared these with 135 patients undergoing combined AVR with CABG using standard CPB. No significant differences were seen in patients demographic characteristics or intraoperative data. Patients in the MECC group experienced a smaller preoperative haemoglobin drop (4.5±0.8 g/dl vs. 5.0±0.5 g/dl, P=0.002) resulting in higher haemoglobin at discharge (11.3±1.3 g/dl vs. 10.8±1.1 g/dl, P=0.03). They had decreased blood products requirements (P=0.004) compared to patients in the standard CPB group. No differences were noted in pulmonary complications, neurological events or mortality. We present for the first time data showing that combined AVR with CABG using MECC is feasible and provides better clinical results compared to standard CPB with regard to blood products requirements, without compromising operative morbidity or mortality.

In vivo measurements of regional hemoglobin oxygen saturation values and limb-to-arm ratios of near-infrared spectroscopy for tissue oxygenation monitoring of lower extremities in healthy subjects.

Objective Near-infrared spectroscopy (NIRS) is a noninvasive technique that allows monitoring of regional hemoglobin oxygen saturation (rSO2) values and might have a role in the diagnosis of peripheral arterial disease. We assessed the reproducibility and inter-subject variability of rSO2 values and rSO2 limb-to-arm ratios (LARs) in lower extremities of healthy subjects. Methods The rSO2 values and rSO2 LARs were calculated in eight healthy subjects without peripheral arterial disease. The rSO2 values were measured at rest at six fixed spots at each lower limb and a reference spot at each upper arm. NIRS provided the rSO2 values without involvement of any other processing technique. After measurements were completed, rSO2 LARs were calculated by dividing the rSO2 value of a lower extremity spot by the rSO2 value of the arm. Measurements were performed twice on 1 day and repeated on 4 different days. Results Mean coefficients of variation of measurements of rSO2 values and rSO2 LARs at the same spot in the same subject were respectively less than 6% and 8% for every measurement spot over time. Coefficients of variation of measurements at the same spot between different subjects were less than 15% and 19% for every measurement spot respectively. Conclusion NIRS is an easily applicable, noninvasive tool for measurement of tissue oxygenation of lower extremities in healthy subjects. The reproducibility of rSO2 values and rSO2 LARs at the same measurement spot in the same subject is good.

Continuous Surveillance of Lower Limb Perfusion During Aortic Surgery With Near-Infrared Spectroscopy: A Pilot Study

Background: Near-infrared spectroscopy (NIRS) is a noninvasive technique that allows continuous monitoring of the regional hemoglobin oxygen saturation (rSO2) index. We evaluated its application to survey perioperative lower limb perfusion. Methods: A total of 10 patients (7 men, aged 71) were monitored during abdominal surgery for aortic aneurysms. The rSO2 index was measured at the M gastrocnemius (optode 1) and at the dorsum of the foot (optode 2). Results: Mean baseline rSO2 values for optodes 1 and 2 were 67 and 66, respectively. After clamping the aorta or iliacofemoral arteries, rSO2 dropped to 32 for optode 1 (P < .0001) and to 27 for optode 2 (P < .0001). After declamping, rSO2 increased to 74 for optode 1 (P = .0012 vs baseline) and also to 74 for optode 2 (P = .0018 vs baseline). Conclusion: Near-infrared spectroscopy is an easily applicable, noninvasive tool for continuous surveillance of lower extremity perfusion during aortic reconstruction.

J-shaped versus median sternotomy for aortic valve replacement with minimal extracorporeal circuit

Abstract Objectives. Minimal access Aortic Valve Replacement (AVR) has been demonstrated to have beneficial effects over median sternotomy. Minimal extracorporeal circulation (MECC) has been shown to have less deleterious effects than conventional cardiopulmonary bypass. We describe for the first time AVR via upper J-shaped partial sternotomy compared to median sternotomy using MECC. Methods. Prospectively collected pre-operative, intra-operative, post-operative and follow-up data from 104 consecutive patients who underwent minimal access AVR were compared to 72 consecutive patients undergoing median sternotomy using MECC during the same period (January 2007 to December 2009). Results. No significant differences were found in patients characteristics or intra-operative data with the exception of pre-existing pulmonary disease. The mean cardiopulmonary bypass (86 ± 18 min vs. 78 ± 15 min, p = 0.0079) and cross-clamp times (65 ± 13 min vs. 59 ± 12 min, p = 0.0013) were significantly shorter in the median sternotomy group. Mediastinal blood loss (397 ± 257 ml vs. 614 ± 339 ml, p < 0.0001) and ventilation time (8 ± 6.9 h vs. 11 ± 16.5 h, p = 0.0054) were significantly less in the minimal access group. No differences were seen in transfusion requirements, inotropic support, intensive care unit (ICU) stay, total hospital stay, post-operative haemoglobin drop, major events or mortality. Quality of life scores after discharge demonstrated less pain with a quicker recovery and return to daily activities in patients receiving J-shaped sternotomy. Conclusions. Minimal access AVR using MECC is feasible and provides excellent clinical results. Less pain and quicker recovery was experienced among patients in this group.