M. Scherer

Extracorporeal membrane oxygenation as perioperative right ventricular support in patients with biventricular failure undergoing left ventricular assist device implantation

OBJECTIVE Left-ventricular assist device (LVAD) implantation complicated by early right ventricle (RV) failure has a poor prognosis. This study details our centers experience with veno-arterial extracorporeal membrane oxygenation (ECMO) as perioperative RV support in patients with preoperative biventricular failure undergoing LVAD implantation. METHODS Ten patients, who underwent LVAD implantation, were retrospectively analyzed. Six patients were already supported with ECMO before LVAD implantation. In four patients, the ECMO was implanted before weaning from cardiopulmonary bypass. RESULTS All patients showed reduced RV function with elevated right-ventricular end-diastolic diameter (RVEDD) (38 ± 4 mm) and RV systolic pressure (48 ± 14 mmHg). The mean pulmonary artery pressure (PAP) was 36 ± 9 mmHg. Nine patients showed dilatation of the tricuspid annulus (≥ 35 mm) with moderate tricuspid valve insufficiency and received tricuspid valve annuloplasty. After removal of the ECMO, none of the patients developed RV failure. ECMO was removed 4±1 days after LVAD implantation. Four patients expired while on LVAD support due to not-device-related sepsis (two patients), mesenteric ischemia (one patient), and gastrointestinal bleeding (one patient), respectively. Overall survival was 60%. CONCLUSION ECMO provided a satisfactory perioperative right-heart support in patients with preoperative biventricular failure undergoing LVAD implantations, who otherwise were better candidates for biventricular assist device. ECMO allowed time for the already compromised right ventricle to get attuned to the increasing preload, and avoids distension and RV failure.

The use of extracorporeal membrane oxygenation in patients with therapy refractory cardiogenic shock as a bridge to implantable left ventricular assist device and perioperative right heart support

Implantation of left ventricular assist device (LVAD) as a bridge to recovery or transplantation is a widely accepted treatment modality. Preexisting organ dysfunction is thought to unfavorably affect patient survival after implantation of a ventricular assist device (VAD). We present our experience using extracorporeal membrane oxygenation (ECMO) in patients with cardiogenic shock to stabilized organ function prior to LVAD implantation. Between September 2006 and March 2008, five patients in cardiogenic shock with preexisting organ dysfunction (impaired liver and kidney function) were supported with ECMO before LVAD implantation. ECMO-LVAD interval was 8 ± 4 days. All patients were transferred to a LVAD. At the LVAD implantation time, glutamic-oxaloacetic transaminase (GOT) decreased from 206.25 ± 106.93 Ul −1 to 70.6 ± 32.9 U l−1, glutamic-pyruvic transaminase (GPT) decreased from 333.5 ± 207.3 U l−1 to 77.8 ± 39.7 U l−1, and creatinine decreased from 2.2 ± 0.9 mg dl−1 to 1.2 ± 0.2 mg dl−1. One patient died while on LVAD support due to not device related sepsis. One patient received successful heart transplantation. Overall survival was 80%. In all patients, we removed the ECMO 3 days after LVAD implantation. After removal of the ECMO there was no right heart failure. ECMO support can immediately stabilize circulation and provide organ perfusion in patients with cardiogenic shock. After improvement of organ function, LVAD implantation can be performed successfully in this patient collective. To avoid right ventricular failure, the ECMO should not be removed at the time of LVAD implantation, and used as a right ventricular support for the immediate postoperative period.

Contributory Role of Fluorine 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnosis and Clinical Management of Infections in Patients Supported With a Continuous-Flow Left Ventricular Assist Device

BACKGROUND The current study sought to demonstrate the advantages offered by fluorine 18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) in patients supported with continuous-flow left ventricular assist devices (CF-LVADs) in detecting infection and the consequent effect on clinical decisions. METHODS Between April 2009 and September 2013, 40 PET examinations were performed in 31 patients (78.1% men; mean age, 51.0 ± 14.9 years) supported with a CF-LVAD. In group A (19 examinations in 14 patients), PET/CT was performed to detect infectious focus in patients without external signs of driveline involvement but with at least two of the following infection signs: recurrent fever, positive blood culture, or elevated infectious indicators. In group B (21 examinations in 17 patients), PET/CT aimed to assess the internal extension of infection in patients with external signs of driveline infection. RESULTS In 50% of the cases of the patients in group A, abnormal (18)F-FDG uptake (9 patients) was related to VAD components. Matching the results with the final diagnosis, we reported 9 true-positive, 8 true-negative, no false-negative, and 2 false-positive findings. New information unrelated to VAD was found in 9 patients (50%): pneumonia in 3, colon diverticulitis in 3, sternal dehiscence in 1, paravertebral abscess in 1, and erysipelas in 1. In group B, superficial abnormal (18)F-FDG uptake was found at the piercing site of the driveline in 2 patients, deeper extension of infection along the driveline in 10, initial involvement of the pump housing in 2, and full involvement of the device in 4. These findings contributed to changing the clinical management in 84.2% of group A patients and in 85.7% of group B patients: 16 patients were scheduled for urgent transplantation, 2 underwent surgical revision of the driveline, 7 required prolonged antibiotic therapy, and 3 underwent colonoscopy. CONCLUSIONS This single-center experience highlights the diagnostic value of PET/CT in detecting the localization and internal extension of infection to internal VAD components. Moreover, this information notably influences the therapeutic management.

Extension of generator longevity by use of high impedance ventricular leads.

SCHERER, M., et al.: Extension of Generator Longevity by Use of High Impedance Ventricular Leads. The resistance of a pacing lead negatively correlates to current consumption. A prospective, randomized trial was conducted to evaluate the effect of a high impedance ventricular lead (CapSure Z) on generator longevity compared to a conventional lead (CapSure SP) eighty‐nine patients were included in the study (51 male, 37 female, age 70.0 ± 10.3 years). Forty‐six patients received a CapSure SP lead (5024 bipolar), and 43 patients received a CapSure Z lead (5034 bipolar) in a randomized fashion. Follow‐up data collected at 5 days, 3, 6, and 12 months postimplant included: lead impedance, pacing and sensing thresholds, impulse energy, and estimated time to replacement. All parameters were collected via pacemaker telemetry; the time to replacement was calculated automatically by a programmed algorithm of the pacemaker. There was no difference in the performance of the atrial lead when a dual chamber device was indicated. The CapSure Z leads displayed statistically significant higher impedance values than the CapSure SP lead in all follow‐up periods. There was no significant difference in lead related complications. No significant differences were observed between pacing and sensing thresholds in both groups. The CapSure Z leads provided a significant reduction in current drain, resulting in a reduction of mean energy consumption at the 12‐month follow‐up from 10.4 ± 5.0 μJ in the CapSure SP group to 6.6 ± 1.4 μJ in the CapSure Z group (median from 9.9 μJ to 6.9 μJ, respectively), providing an estimated increase in mean longevity of more than 1 year from 81.1 ± 23.5 months in the CapSure SP group to 94.5 ± 13.4 months in the CapSure Z group (median: 76.5 months to 95.0 months, respectively). The use of a high resistance lead for ventricular pacing appears to result in a clinically relevant extension of generator longevity.

C1-esterase inhibitor reduces reperfusion injury after lung transplantation

BACKGROUND Activation of the complement system and polymorphonuclear neutrophilic leukocytes plays a major role in mediating reperfusion injury after lung transplantation. We hypothesized that early interference with complement activation would reduce lung reperfusion injury after transplantation. METHODS Unilateral left lung autotransplantation was performed in 6 sheep. After hilar stripping the left lung was flushed with Euro-Collins solution and preserved for 2 hours in situ at 15 degrees C. After reperfusion the right main bronchus and pulmonary artery were occluded, leaving the animal dependent on the reperfused lung (reperfused group). C1-esterase inhibitor group animals (n = 6) received 200 U/kg body weight of C1-esterase inhibitor as a short infusion, half 10 minutes before, the other half 10 minutes after reperfusion. Controls (n = 6) underwent hilar preparation only. Pulmonary function was assessed by alveolar-arterial oxygen difference and pulmonary vascular resistance. The release of beta-N-acetylglucosaminidase served as indicator of polymorphonuclear neutrophilic leukocyte activation. Extravascular lung water was an indicator for pulmonary edema formation. Biopsy specimens were taken from all groups 3 hours after reperfusion for light and electron microscopy. RESULTS In the reperfused group, alveolar-arterial oxygen difference and pulmonary vascular resistance were significantly elevated after reperfusion. All animals developed frank alveolar edema. The biochemical marker beta-N-acetylglucosaminidase showed significant leukocyte activation. In the C1-esterase inhibitor group, alveolar-arterial oxygen difference, pulmonary vascular resistance, and the level of polymorphonuclear neutrophilic leukocyte activation were significantly lower. CONCLUSIONS Treatment with C1-esterase inhibitor reduces reperfusion injury and improves pulmonary function in this experimental model.

Electromagnetic interaction between an axial left ventricular assist device and an implantable cardioverter defibrillator.

Harvesting the long saphenous vein by means of multiple small incisions and use of the mayo strippers is a well-recommended technique. We found that SVH was associated with less wound complications and wound pain, required shorter length of hospital stay, and did not add any cost to the procedure. It did not prolong the overall operative time nor compromise the vein quality both morphologically and functionally. We found that this maneuver facilitated vein dissection. It kept the vein very well hydrated and protected its integrity. It facilitated removal of the debris and clots generated after sliding the stripper. Further research is required to evaluate the potential benefits of this maneuver.

Heparin-Induced Thrombocytopenia During Extracorporeal Membrane Oxygenation

HEPARIN-INDUCED THROMBOCYTOPENIA (HIT) is an immune-mediated adverse effect of heparin therapy. Two clinical entities of HIT can be distinguished: HIT I and HIT II. HIT I is a harmless pharmacologic phenomenon associated with decreased platelet count within 24–48 h after initiation of heparinization. Unlike HIT II, it is not associated with thrombosis and does not necessitate discontinuation of heparin. In contrast, HIT II can cause both bleeding and thrombotic complications. It is the most important and most frequent drug-induced immunologic thrombocytopenia. Besides orthopedic and vascular surgery patients, patients after cardiac surgery are at highest risk of developing HIT II (1–5%). Its clinical importance is based on its strong association with venous and arterial thrombosis and thromboembolism (heparin-induced thrombocytopenia with associated thrombosis, HITT). HIT is caused by the development of an IgG antibody that recognizes multimolecular complexes of platelet factor 4 (PF4) and heparin. This so-called heparin-PF4-IgG complex leads to platelet activation and release of additional PF4 from alpha granules in platelets when bound to the platelet Fc receptor. Note that heparin forms a necessary part of the complex leading the further PF4 release. PF4 released in excess binds to heparin-like molecules on the surface of endothelial cells leading to immunemediated endothelial cell injury and heightening the risk for HITT and disseminated intravascular coagulation (DIC). The mainstay of therapy in HIT/HITT is the avoidance of further exposure to heparin in any form, avoidance of platelet transfusions and deferral of vitamin-K-antagonists until platelet recovery. Early use of alternative anticoagulants is inevitable when the indication for anticoagulation persists or in individuals with HITT. Extracorporeal membrane oxygenation (ECMO) remains a last line life-saving therapeutic option in patients suffering from

The influence of selective pulmonary perfusion on the inflammatory response and clinical outcome of patients with chronic obstructive pulmonary disease undergoing cardiopulmonary bypass

OBJECTIVES Patients undergoing cardiac surgery presenting with chronic obstructive pulmonary disease (COPD) have a higher 30-day mortality risk. In these patients, pulmonary dysfunction linked to an inflammatory response is frequent after cardiac operations using cardiopulmonary bypass (CPB), which causes pulmonary hypoperfusion. We hypothesize that selective pulmonary perfusion (sPP) of the lungs leads to a reduction of pulmonary inflammation and a better clinical outcome. METHODS Fifty-nine COPD patients (forced expiratory volume in 1 s/vital capacity <70%) undergoing cardiac surgery procedures (coronary artery bypass grafting 64%, valve 14%) were block-randomized to sPP (venous blood, temperature 2°C, 4 l) or standard CPB (28/28). The primary end-point of the study was to evaluate the effect of pulmonary perfusion on gas exchange by measuring alveolar-arterial oxygen gradient. The surrogate end-points were inflammatory response, intensive care unit (ICU) stay, time on respirator (TOR) and major adverse cardiac and cerebrovascular events. A cytokine assay for interleukin-1β, IL-6, IL-10, tumour necrosis factor-α (TNF-α) and polymorphonuclear elastase was performed with peripheral blood at different time-points [(t1) pre-CPB, (t2) end of CPB, (t3) 3 h, (t4) 24 h, (t5) 48 h postoperatively]. Repeated-measure analysis of variance and non-parametric statistics were used to assess the between-group and during time differences. RESULTS The two groups proved comparable for perioperative variables. Serum cytokines were not different in the two groups throughout the study (P > 0.05 at single time-points), but as a function of time, the markers of the inflammatory response increased after CBP (P < 0.05 pre-CPB to 24 h). Clinical end-points were statistically comparable in both groups, but with a trend towards a shorter TOR (72 ± 159 h/106 ± 193 h) and ICU stay (3.9 ± 7.2 days/5.5 ± 9.2 days) in the sPP group despite a slightly longer time on extracorporeal circulation (120 vs 158 min). CONCLUSIONS These results indicate a non-significant trend that repeated hypothermic lung perfusion with venous blood during CPB may have a protective effect on the lungs. A multicentre study design and larger cohort seem necessary to demonstrate the benefits of sPP more clearly.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography for improving diagnosis of infection in patients on CF-LVAD: longing for more ‘insights’

Aim Presence and consequent extent of infection in patients on continuous-flow left ventricular assist devices (CF-LVADs) can be challenging with the current diagnostic tools. The present study sought to demonstrate the diagnostic power of 18F-Fluorodeoxyglucose-Positron-Emission Tomography/Computed Tomography (18F-FDG PET/CT) in detecting infection in patients supported with CF-LVAD. Background The present study sought to demonstrate the diagnostic power of 18F-fluorodeoxyglucose-positron-emission tomography/computed tomography (18F-FDG PET/CT) in detecting infection in patients supported with CF-LVAD. Methods and results Between July 2009 and April 2016, 61 PET/CT examinations were performed in 47 patients (median age 64.13 years, IQR 18.77) supported with a CF-LVAD. PET/CT assessments were performed qualitatively and quantitatively at three different levels: at the piercing site of driveline (first level), along the intracorporeal course of driveline (second level), and around the device (third level). Final diagnosis of LVAD infection was prospectively performed and was based upon microbiological samples taken at hospital admission, during the surgical revision/transplantation and recurrence of symptoms on long-term follow-up. At last follow-up a total of 40 (65.57%) final diagnoses of LVAD-infection could be ascertained. Matching the final diagnosis with the PET/CT assessments the sensitivity, specificity, and positive and negative predictive value were 90.0, 71.4, 85.71, and 78.94%, respectively. Level sub-analyses of SUV max showed an optimal discriminator power for levels 1 and 2 (AUC of level 1-0.824, P < 0.001; AUC of level 2-0.849, P < 0.001, respectively). At the third level semi-quantitative analysis showed poor discriminator power (AUC 0.589, P = 0.33). Qualitative visual analysis instead indicated a trend toward significance (P = 0.07). Conclusions Quantitative 18F-FDG PET/CT is an optimal diagnostic tool in detecting superficial and deep driveline infections. However, diagnostic accuracy with regard to the diagnosis of pump housing infection is limited. Here, clinical and qualitative PET/CT analyses must be better considered.

Minimally Invasive Implantation of HeartWare Assist Device and Simultaneous Tricuspid Valve Reconstruction Through Partial Upper Sternotomy.

Left ventricular assist device (LVAD) implantation is a well-established therapy to support patients with end-stage heart failure. However, the operative procedure is associated with severe trauma. Third generation LVADs like the HeartWare assist device (HeartWare, Inc., Framingham, MA, USA) are characterized by enhanced technology despite smaller size. These devices offer new minimally invasive surgical options. Tricuspid regurgitation requiring valve repair is frequent in patients with the need for mechanical circulatory support as it is strongly associated with ischemic and nonischemic cardiomyopathy. We report on HeartWare LVAD implantation and simultaneous tricuspid valve reconstruction through minimally invasive access by partial upper sternotomy to the fifth left intercostal space. Four male patients (mean age 51.72 ± 11.95 years) suffering from chronic heart failure due to dilative (three patients) and ischemic (one patient) cardiomyopathy and also exhibiting concomitant tricuspid valve insufficiency due to annular dilation underwent VAD implantation and tricuspid valve annuloplasty. Extracorporeal circulation was established via the ascending aorta, superior vena cava, and right atrium. In all four cases the LVAD implantation and tricuspid valve repair via partial median sternotomy was successful. During the operative procedure, no conversion to full sternotomy was necessary. One patient needed postoperative re-exploration because of pericardial effusion. No postoperative focal neurologic injury was observed. New generation VADs are advantageous because of the possibility of minimally invasive implantation procedure which can therefore minimize surgical trauma. Concomitant tricuspid valve reconstruction can also be performed simultaneously through partial upper sternotomy. Nevertheless, minimally invasive LVAD implantation is a challenging operative technique.