Stefaan Bouchez

Acute and critically ill peripartum cardiomyopathy and 'bridge to' therapeutic options: a single center experience with intra-aortic balloon pump, extra corporeal membrane oxygenation and continuous-flow left ventricular assist devices

IntroductionPeripartum cardiomyopathy (PPCM) patients refractory to medical therapy and intra-aortic balloon pump (IABP) counterpulsation or in whom weaning from these therapies is impossible, are candidates for a left ventricular assist device (LVAD) as a bridge to recovery or transplant. Continuous-flow LVADs are smaller, have a better long-term durability and are associated with better outcomes. Extra corporeal membrane oxygenation (ECMO) can be used as a temporary support in patients with refractory cardiogenic shock. The aim of this study was to evaluate the efficacy and safety of mechanical support in acute and critically ill PPCM patients.MethodsThis was a retrospective search of the patient database of the Ghent University hospital (2000 to 2010).ResultsSix PPCM-patients were treated with mechanical support. Three patients presented in the postpartum period and three patients at the end of pregnancy. All were treated with IABP, the duration of IABP support ranged from 1 to 13 days. An ECMO was inserted in one patient who presented with cardiogenic shock, multiple organ dysfunction syndrome and a stillborn baby. Two patients showed partial recovery and could be weaned off the IABP. Four patients were implanted with a continuous-flow LVAD (HeartMate II®, Thoratec Inc.), including the ECMO-patient. Three LVAD patients were successfully transplanted 78, 126 and 360 days after LVAD implant; one patient is still on the transplant waiting list. We observed one peripheral thrombotic complication due to IABP and five early bleeding complications in three LVAD patients. One patient died suddenly two years after transplantation.ConclusionsIn PPCM with refractory heart failure IABP was safe and efficient as a bridge to recovery or as a bridge to LVAD. ECMO provided temporary support as a bridge to LVAD, while the newer continuous-flow LVADs offered a safe bridge to transplant.

Elastic Image Registration Versus Speckle Tracking for 2-D Myocardial Motion Estimation: A Direct Comparison In Vivo

Despite the availability of multiple solutions for assessing myocardial strain by ultrasound, little is currently known about the relative performance of the different methods. In this study, we sought to contrast two strain estimation techniques directly (speckle tracking and elastic registration) in an in vivo setting by comparing both to a gold standard reference measurement. In five open-chest sheep instrumented with ultrasonic microcrystals, 2-D images were acquired with a GE Vivid7 ultrasound system. Radial (ε_RR), longitudinal (ε_LL), and circumferential strain (ε_CC) were estimated during four inotropic stages: at rest, during esmolol and dobutamine infusion, and during acute ischemia. The correlation of the end-systolic strain values of a well-validated speckle tracking approach and an elastic registration method against sonomicrometry were comparable for ε_LL (<i>r</i>=0.70 versus <i>r</i>=0.61 , respectively; <i>p</i>=0.32) and ε_CC (<i>r</i>=0.73 versus <i>r</i>=0.80 respectively; <i>p</i>=0.31). However, the elastic registration method performed considerably better for ε_RR (<i>r</i>=0.64 versus <i>r</i>=0.85 respectively; <i>p</i>=0.09). Moreover, the bias and limits of agreement with respect to the reference strain estimates were statistically significantly smaller in this direction (<i>p</i> <; 0.001). This could be related to regularization which is imposed during the motion estimation process as opposed to an a posteriori regularization step in the speckle tracking method. Whether one method outperforms the other in detecting dysfunctional regions remains the topic of future research.

The effect of retrograde autologous priming volume on haemodilution and transfusion requirements during cardiac surgery

OBJECTIVES Many cardiac procedures using cardiopulmonary bypass (CPB) still require intraoperative transfusion. Retrograde autologous priming (RAP) has been introduced to decrease haemodilution and the blood transfusion rate. This study is designed to determine the influence or RAP on intraoperative haematocrit, transfusion and its clinical consequences. METHODS The RAP effect was retrospectively studied in 753 patients during contemporary cardiac surgery, targeting a haematocrit of 25%. Multivariate linear regression analysis was performed to identify the independent factors influencing intraoperative haematocrit, transfusion rate and transfusion quantity. RESULTS RAP was used in 498 patients and compared with 255 controls. RAP decreased the haemodilution level (nadir haematocrit 26.8 standard deviation [SD] 4.0% in RAP vs 25.8 SD 3.6% in controls; P = 0.001) and transfusion frequency (26.1 vs 33.3%, P = 0.04), despite smaller patients (body surface area [BSA] 1.86 SD 0.20 m(2) vs 1.91 SD 0.21 m(2) in RAP vs controls; P = 0.002) with lower preoperative haematocrit (38.9 SD 4.4% vs 40.5 SD 4.6%; P < 0.001). Optimal RAP volume was overall 475 ml (ROC area 0.55; 95% confidence interval [CI] 0.50-0.60; P = 0.04) and 375 ml in patients with BSA <1.7 m(2) (ROC area 0.63; 95% CI 0.54-0.73; P = 0.008) to decrease the transfusion incidence. Multivariate analysis revealed RAP volume as a significant determinant of nadir haematocrit (β = 0.003, 95% CI 0.002-0.004, P < 0.001) and transfusion rate (odds ratio (OR) = 0.997, 95% CI 0.996-0.999, P < 0.001), independent of BSA, gender and preoperative haematocrit. CONCLUSIONS Retrograde autologous priming is an effective adjunct to decrease the blood transfusion rate, coping with the CPB-related haemodilution and its adverse clinical effects. A RAP volume individualized to each patient offers most benefit as part of a multidisciplinary blood conservation approach.

Acute and chronic effects of dysfunction of right ventricular outflow tract components on right ventricular performance in a porcine model: implications for primary repair of tetralogy of fallot

OBJECTIVES This study investigates the contribution of infundibular versus pulmonary valve (PV) dysfunction on right ventricular (RV) function in a porcine model. BACKGROUND Clinical outcome after repair of tetralogy of Fallot is determined by the adaptation of the right ventricle to the physiological sequelae of the right ventricular outflow tract (RVOT) reconstruction. Recent surgical techniques are pursuing a PV-versus infundibulum-sparing approach. METHODS In a porcine model, 3 types of RVOT dysfunction were created and compared with sham-operated controls: infundibular dysfunction (INF), PV insufficiency (PI), and combined infundibular-PV dysfunction (TAP). Both acute and chronic effects on RV function were studied by using conductance technology and magnetic resonance imaging. RESULTS In animals with PI, pulmonary regurgitant fraction progressed more in the presence of concomitant INF (54% in TAP versus 14% in PI; p = 0.03). Subsequently, RV end-systolic and end-diastolic volume increased more in both groups, resulting in decreased ejection fraction after 3 months. Preload-independent systolic indices showed acute impairment of RV contractility in all treatment groups but most in animals with infundibular scarring (INF and TAP). Further chronic deterioration was observed in animals of the TAP group. RV compliance improved proportionally most in the PI and TAP groups in relation to the extent of RV dilation. CONCLUSIONS Surgical RVOT dysfunction, whether it includes the infundibulum and/or the PV, has an immediate effect on RV performance. Although impaired RV contractility is due to intrinsic myocardial damage by infundibular distortion, it is chronically furthered by PI-related RV dilation. These findings support the adoption of a RVOT-sparing strategy to treat tetralogy of Fallot.

Effect of remote ischemic conditioning on atrial fibrillation and outcome after coronary artery bypass grafting (RICO-trial)

BackgroundPre- and postconditioning describe mechanisms whereby short ischemic periods protect an organ against a longer period of ischemia. Interestingly, short ischemic periods of a limb, in itself harmless, may increase the ischemia tolerance of remote organs, e.g. the heart (remote conditioning, RC). Although several studies have shown reduced biomarker release by RC, a reduction of complications and improvement of patient outcome still has to be demonstrated. Atrial fibrillation (AF) is one of the most common complications after coronary artery bypass graft surgery (CABG), affecting 27-46% of patients. It is associated with increased mortality, adverse cardiovascular events, and prolonged in-hospital stay. We hypothesize that remote ischemic pre- and/or post-conditioning reduce the incidence of AF following CABG, and improve patient outcome.Methods/designThis study is a randomized, controlled, patient and investigator blinded multicenter trial. Elective CABG patients are randomized to one of the following four groups: 1) control, 2) remote ischemic preconditioning, 3) remote ischemic postconditioning, or 4) remote ischemic pre- and postconditioning. Remote conditioning is applied at the arm by 3 cycles of 5 minutes of ischemia and reperfusion. Primary endpoint is the incidence AF in the first 72 hours after surgery, detected using a Holter-monitor. Secondary endpoints include length-of-stay on the intensive care unit and in-hospital, and the occurrence of major adverse cardiovascular events at 30 days, 3 months and 1 year.Based on an expected incidence in the control group of 27%, 195 patients per group are needed to detect with 80% power a reduction by 45% following either pre- or postconditioning, while allowing for a 10% dropout and at an alpha of 0.05. With the combined intervention expected to be stronger, we need 75 patients in this group to detect a reduction in incidence of AF of 60%.DiscussionThe RICO-trial (the effect of Remote Ischemic Conditioning on atrial fibrillation and Outcome) is a randomized controlled multicenter trial, designed to investigate whether remote ischemic pre- and/or post-conditioning of the arm reduce the incidence of AF following CABG surgery.Trial registrationClinicalTrials.gov under NCT01107184.

Role of myocardial hypertrophy on acute and chronic right ventricular performance in relation to chronic volume overload in a porcine model: relevance for the surgical management of tetralogy of Fallot.

OBJECTIVES The age for correction of tetralogy of Fallot has progressively declined to the postnatal period, often despite an increased rate of transannular patch repair. However, the long-term effect of premature exposure to chronic pulmonary insufficiency on the right ventricle remains unknown. On the basis of the relationship between the duration of pressure overload and age, the role of previous pressure load-related hypertrophy on right ventricular (RV) performance after chronic volume overload was investigated in a porcine model. METHODS RV hypertrophy (RVH), induced by pulmonary artery banding, was studied in pigs with (RVH plus pulmonary insufficiency [PI]) and without (RVH) subsequent PI. The effect of volume overload was compared between these 2 groups and pigs without RVH but with PI and controls (sham). Both acute and chronic effects on RV function were studied using conductance technology and validated using echocardiography. RESULTS After chronic volume overload, the end-systolic and end-diastolic volumes were smaller in the RVH+PI group than in the PI group, including a lower pulmonary regurgitation fraction (25% ± 5% vs 35% ± 5%; P = .002). RVH resulted in better preserved systolic function, confirmed by an increased preload recruitable stroke work slope (14.7 ± 1.8 vs 9.3 ± 1.3 Mw.s/mL; P = .025) and higher RV ejection fraction (51% ± 3% vs 45% ± 4%; P = .05). Myocardial stiffness was impaired in the RVH+PI group versus the PI group (β, 0.19 ± 0.03 vs 0.12 ± 0.02 mL(-1); P = .001), presenting restrictive physiology only in the condition associating RVH and PI. CONCLUSIONS The results of the present study have demonstrated that RVH attenuates the RV remodeling process related to chronic PI. It enables better preservation of contractility but at the cost of sustained diastolic impairment. These findings might help to determine the timing and strategy for repair of tetralogy of Fallot when RV outflow tract morphology indicates a definite need for transannular reconstruction.

A pathophysiological approach towards right ventricular function and failure.

The scope of this review is to provide a pathophysiological summary of perioperative right ventricular function and failure. In recent decades, the importance of right ventricular function in the perioperative period has been established. However, much of our current knowledge on the management of this clinical entity is based on extrapolation of results from left ventricular research, although biventricular physiology is known to be markedly different in many aspects. Here, on the basis of a thorough literature search, we review theoretical as well as practical aspects of perioperative right ventricular failure. After underlining the importance of this topic, we review basic right ventricular anatomy and physiology, with an emphasis on the role of ventricular interaction. Next, potential causes of perioperative right ventricular failure are discussed. The emphasis of this review is on the perioperative anaesthetic considerations, ranging from preoperative assessment through intraoperative monitoring to specific contemporary therapeutic options of perioperative right ventricular failure.

Sequential off-pump coronary artery bypass and liver transplantation.

End-stage cirrhotic patients in need of liver transplantation (LTX) and coronary artery bypass grafting (CABG) are a challenging problem. Few reports have been published on combined CABG–LTX, all using cardiopulmonary bypass (CPB) [1–7]. We performed sequential coronary artery bypass using off-pump coronary artery bypass (OPCAB) technique and a LTX using a temporary porto-caval shunt. A 66-year-old man weighing 67 kg, with alcoholic liver-cirrhosis, hepatocellular carcinoma and advanced liver disease (child C) was presented for LTX. The patient suffered from portal hypertension, ascites, abdominal distension, severe fatigue, glucose intolerance and nicotine abuses. Laboratory data included prothrombin time 66% (70– 100%), activated partial thromboplastin time 21 s (27– 41 s), fibrinogen 277 mg/dl (156–400 mg/dl), creatinine 0.82 mg/dl (0.72–1.17 mg/dl), total protein 6.8 g/dl (6.2– 8.2 g/dl), albumin 2.6 mg/dl (3.4–4.8 mg/dl), total bilirubin 2.7 mg/dl (0.2–1.1 mg/dl), platelet count of 161 000/ll (140 000–362 000/ll), haematocrit 39% (40–52%). His history showed an acute myocardial infarction 4 years ago. A preoperative coronary angiography revealed a triple vessel disease with >95% stenosis. Transoesophageal echocardiography (TEE) showed a left ventricular ejection fraction of 47% and anteroseptal and inferior hypokinesis. We opted for a combined OPCAB–LTX after discussion in our multidisciplinary liver meeting. A month later a suitable liver graft was available. General anaesthesia was induced using fentanyl, diazepam and rocuronium and was maintained with sevoflurane, cis-atracurium and boluses of fentanyl. A SwanGanz catheter (Edwards Lifesciences, Irvine, CA, USA) was inserted to measure mixed-venous oxygen saturation. A TEE was placed to monitor cardiac function. The OPCAB procedure was started with a sternotomy. During OPCAB nitroglycerine infusion was administered. Heparin 1.5 mg/kg was given before clamping and was reversed with protamine at the end of the procedure. Two bypasses were performed: left internal mammarian artery to left anterior descending artery and a saphenous graft to the right coronary artery. Clamping time was 5.5 and 5 min respectively. The cardiac index improved from 2.7 to 3.6 l/min/m. The chest was closed after placing two chest drains and we proceeded the LTX with a classical Mercedes–Benz incision. Before total hepatectomy the portal inflow was disconnected by making an end-to-side porto-caval shunt. The implantation was made by lateral caval clamping and a cavo-caval (end-to-side) anastomosis. At the end of the portal anastomosis the graft was slowly reperfused. Standard arterial and biliary anastomosis was thereafter carried out. After reperfusion the cardiac function remained stable. The patient received adrenaline, noradrenaline and nitroglycerine during the dissection and reperfusion phase. Before reperfusion mannitol, CaCl2, furosemide, methylprednisolone and sodium bicarbonate were given. During the neo-hepatic phase noradrenaline and nitroglycerine were discontinued, adrenaline doses were reduced. Coagulation was monitored using the Sonoclot (Sienco Inc, Arvada, CO, USA) and standard coagulation tests and was corrected with 16 units of fresh frozen plasma, aprotinin and 8 units of platelets. Six units of packed cells were administered during the operation. Total operation time was 10.5 h. Cold and warm liver ischaemic times were 5.5 and 1 h respectively. Postoperatively the patient was transferred to the intensive care. The patient received corticosteroids and tacrolimus as immunosuppressant drugs. Liverand heart function remained good. The patient was extubated the next day and discharged to the ward after 5 days. Six months after the operation his liver and cardiac function remained good. There are several therapeutic options for patients with both coronary artery disease and child C liver cirrhosis demanding CABG and LTX. LTX could be performed first and CABG in a second time, but performing LTX in the presence of coronary artery disease increases the risk for myocardial ischaemia and infarction [5]. A second option is to perform CABG prior to LTX. The literature shows that the hospital morbidity and mortality of patients with mild or moderate liver cirrhosis

Three-dimensional myocardial strain estimation from volumetric ultrasound: Experimental validation in an animal model

Although real-time three-dimensional echocardiography has the potential to allow for more accurate assessment of global and regional ventricular dynamics compared to the more traditional two-dimensional ultrasound examinations, it still requires rigorous testing and validation against other accepted techniques should it breakthrough as a standard examination in routine clinical practice. Very few studies have looked at a validation of regional functional indices in an in-vivo context. The aim of the present study therefore was to validate a previously proposed 3D strain estimation-method based on elastic registration of subsequent volumes on a segmental level in an animal model. Volumetric images were acquired with a GE Vivid7 ultrasound system in five open-chest sheep instrumented with ultrasonic microcrystals. Radial (εRR), longitudinal (εLL) and circumferential strain (εCC) were estimated during four stages: at rest, during esmolol and dobutamine infusion, and during acute ischemia. Moderate correlations for εLL (r=0.63; p<;0.01) and εCC (r=0.60; p=0.01) were obtained, whereas no significant radial correlation was found. These findings are comparable to the performance of the current state-of-the-art commercial 3D speckle tracking methods.

Motion and deformation estimation of cardiac ultrasound sequences using an anatomical B-spline transformation model

We present a novel method for tracking myocardial motion in 2D ultrasound sequences based on non-rigid registration using an anatomical free-form deformation (AFFD) model where the basis functions are locally oriented along the radial and circumferential direction of the left ventricle (LV). This formulation allows us to model the LV motion more naturally compared to previously proposed FFDs defined on a regular Cartesian grid (CFFD). In this paper we compare the performance of the AFFD against the CFFD model in an in-vivo setting. Short-axis images were acquired in five open-chest sheep using sonomicrometry as ground-truth deformation estimates. We demonstrated that regional end-systolic strain values assessed with the AFFD model are comparable with CFFD, while also displaying a statistically lower drift at the end of the cardiac cycle and a better agreement with a manual end-systolic reference. Furthermore, tracking using AFFD was visually more appealing to clinical experts.