Postoperative vasoplegia in lung transplantation: incidence and relation to outcome in a single-centre retrospective study.

BACKGROUND: The incidence and clinical importance of vasoplegia after lung transplantation remains poorly studied. We describe the incidence of vasoplegia and its association with complications after lung transplantation. METHODS: Perioperative data of 279 lung transplant recipients operated on from 2015 to 2020 in a UK hospital were analysed retrospectively. RESULTS: Vasoplegia occurred in 41.6% of patients after lung transplantation (mild, 31.0%; moderate, 55.2%; severe, 13.8%). Compared with non-vasoplegic patients, vasoplegic patients had a higher incidence of any acute kidney injury, defined by Kidney Disease Improving Global Outcomes (KDIGO) criteria (78.5% vs 65%, P=0.015), renal replacement therapy (47.4% vs 24.5%, P<0.001), and delayed chest closure (18.4% vs 9.2%, P=0.025); were ventilated longer (70 [32-368] vs 34 [19-105] h, P<0.001); and stayed longer in the ICU (12.9 [5-30] vs 6.8 [3-20] days, P<0.001). Mortality at 30 days and 1 yr was higher in patients with vasoplegia (11.2% vs 5.5% and 20.7% vs 11.7%, P=0.039, respectively). Severe vasoplegia represented a predictor of longer-term mortality (hazard ratio=1.65, P=0.008). Underlying infectious disease, increased BMI, higher preoperative pulmonary artery systolic pressure and bilirubin levels, lower glomerular filtration rate, and increased fresh frozen plasma transfusion were predictors of vasoplegia severity. Neutrophilia, leucocytosis, and increased C-reactive protein were associated with vasoplegia, but release of the neutrophil activation markers myeloperoxidase and heparin-binding protein was similar between groups. CONCLUSIONS: Influenced by preoperative status as well as procedural factors and inflammatory response, vasoplegia is a common and critical condition after lung transplantation with worse short-term outcomes and long-term survival.

Outcomes of heart transplantation in patients bridged with Impella 5.0: Comparison with native chest transplanted patients without preoperative mechanical circulatory support.

The Impella (Abiomed, Danvers, MA, USA) has become an important adjunct treatment modality in bridging patients with end-stage heart failure to recovery or orthotopic heart transplantation (HTx). We compared the outcome of patients directly bridged to HTx with the Impella 5.0 versus patients without mechanical circulatory support (MCS). Patients with no previous sternotomy or MCS, who were transplanted between September 2014 and March 2019 were included in this retrospective analysis. Impella 5.0 was implanted using surgical access and transesophageal echocardiography guidance. Forty-two out of 155 transplanted patients fulfilled the insertion criteria. Eight (19%) were bridged with Impella 5.0 to HTx. Recipient and donor baseline characteristics were comparable in both groups. There were no significant differences in survival between the groups at 30-day (94% no MCS vs. 87.5% Impella group, P = .47) or 6 months (94% vs. 87.5%, P = .51). Patients on Impella 5.0 showed a significant recovery of hemodynamic parameters and end-organ function. Average duration of support to HTx was 16 ± 17 days. Impella 5.0, when used in suitable patients in a timely fashion can be a good strategy for bridging patients to HTx. The axillary approach allows for early extubation and mobilization. Outcomes of patients bridged to HTx with Impella 5.0 in acute cardiogenic shock are comparable to those of patients with no MCS.

Use of oxygenator with short-term ventricular assist devices.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) serves as a conventional short-term mechanical circulatory assist to support heart and lung functions. The short-term ventricular assist devices (ST-VAD) can, on the contrary, offer only circulatory support. A combination of VAD and oxygenator (Oxy-VAD) could help overcome this potential disadvantage. This is a retrospective case note study of patients supported on ST-VAD which required adding an oxygenator for extra respiratory support. The oxygenator was introduced in the ST-VAD circuit, either on the left or the right side. Twenty-two patients with the etiology of refractory cardiogenic shock in decompensation were supported on Oxy-VAD between years 2009 and 2019 at tertiary care . All patients were classified into class-I INTERMACS with a mean SOFA Score of 14 ± 2.58. 86.4% of patients were already on mechanical support pre-ST-VAD implant, 80% on VA-ECMO. The BiVAD implant accounted for 63.6%, followed by LVAD and RVAD with 27.3% and 9.1%. Mean duration of the ST-VAD was 8.5 days. The oxygenator was introduced in 14 RVAD and 8 LVAD circuits. The oxygenator was successfully weaned in 54.5% while ST-VAD was explanted in 31.8%. Discharge to home survival was 22.7%. Oxy-VAD proves a viable, and probably, a better option to VA-ECMO in acute cardiorespiratory decompensation. It offers organ-specific tailor-made support to the right and/or left heart and/or lungs. While on Oxy-VAD support, each organ performance can be assessed independently, and the assistance of the specifically improved organ can be weaned off without discontinuing the support for the rest.

Severe aortic valve regurgitation requiring mechanical aortic valve replacement following Impella device implantation.

INTRODUCTION: We describe a patient who developed severe aortic regurgitation following Impella left ventricular assist device implantation requiring aortic valve replacement. CASE REPORT: A previously healthy 34-year-old female presented with chest pain and flu-like symptoms. Electrocardiogram showed widespread ST elevation and serum troponin was raised, consistent with myocarditis. Coronary angiography was normal but the right coronary artery dissected. Subsequent cardiogenic shock required veno-arterial extracorporeal membrane oxygenation and Impella implantation. Myocardial function recovered, but upon removal of the Impella, severe aortic regurgitation was present and she underwent aortic valve replacement, making a full recovery. DISCUSSION: Aortic regurgitation is a rare complication of Impella implantation, and to our knowledge, this is the first reported case successfully treated with aortic valve replacement. Veno-arterial extracorporeal membrane oxygenation and Impella used in tandem are relatively novel, and may add synergistic benefit to strategies for acute cardiogenic shock. CONCLUSION: Echocardiography must include frequent assessment of both valvular and myocardial function after Impella removal.

Utilization of extracorporeal membrane oxygenation in DCD and DBD lung transplants: a 2-year single-center experience.

Donation after circulatory death (DCD) has the potential to expand the lung donor pool. We aimed to assess whether DCD affected the need for perioperative extracorporeal membrane oxygenation (ECMO) and perioperative outcomes in lung transplantation (LTx) as compared to donation after brain death (DBD). All consecutive LTxs performed between April 2017 and March 2019 at our tertiary center were analyzed. Donor and recipient preoperative characteristics, utilization of ECMO, and perioperative clinical outcomes were compared between DCD and DBD LTx. Multivariate models (frequentist and Bayes) were fitted to evaluate an independent effect of DCD on the intra- and postoperative need for ECMO. Out of 105 enrolled patients, 25 (23.8%) were DCD LTx. Donors' and preoperative recipients' characteristics were comparable between the groups. Intraoperatively, mechanical circulatory support (MCS) was more common in DCD LTx (56.0% vs. 36.2%), but the adjusted difference was minor (RR = 1.16, 95% CI 0.64-2.12; P = 0.613). MCS duration, and first and second lung ischemia time were longer in the DCD group. Postoperatively, DCD recipients more commonly required ECMO (32.0% vs. 7.5%) and the difference remained considerable after adjustment for the pre- and intraoperative covariates: RR = 4.11 (95% CI 0.95-17.7), P = 0.058, Bayes RR = 4.15 (95% CrI 1.28-13.0). Sensitivity analyses (two DCD-DBD matching procedures) supported a higher risk of postoperative ECMO need in DCD patients. Incidence of delayed chest closure, postoperative chest drainage, and renal replacement therapy was higher in the DCD group. Early postoperative outcomes after DCD LTx appeared generally comparable to those after DBD LTx. DCD was associated with a higher need for postoperative ECMO which could influence clinical outcomes. However, as the DCD group had a significantly higher use of EVLP with more common ECMO preoperatively, this might have contributed to worse outcomes in the DCD group.

Initial experience with Impella RP in a quaternary transplant center.

Right ventricular failure is one of the most common complications encountered after left ventricular assist device implantation and heart transplantation. It has been reported to have an incidence up to 30%. It increases morbidity and short-term mortality. Impella RP is a small pump that can provide up to 4L/min of flow. We analyzed all the patients with right ventricular failure that were treated with Impella RP in our institution. The Impella RP was implanted percutaneously in the catheterization laboratory guided by fluoroscopy. Overall, 7 patients required the implantation of an Impella RP due to right ventricular failure: 2 after long-term LVAD, 3 presented with acute right ventricular failure immediately after LVAD implantation, and 2 needed it after heart transplantation. Regarding complications, we report 2 patients with hemolysis. Hemodynamic parameters as well as end-organ perfusion and inotropic requirements improved after the insertion of the Impella. Overall, 30-day survival is 58%. Median time of support was 9 (5-19) days. RV failure is one of the most challenging complications after LVAD implantation and heart transplantation. The major challenge is the timing of implantation. The minimally invasive nature of the Impella RP facilitates de-escalation of treatment and paves the road to recovery. Impella RP proved useful in facilitating ECMO wean. Used in a prompt manner alongside the ease of implantation and the minimal rate of complications, Impella RP seems to be an appropriate device to tackle RV failure providing enough flow to allow for recovery or escalation decision-making.

Intravascular donor monocytes play a central role in lung transplant ischaemia-reperfusion injury.

RATIONALE: Primary graft dysfunction in lung transplant recipients derives from the initial, largely leukocyte-dependent, ischaemia-reperfusion injury. Intravascular lung-marginated monocytes have been shown to play key roles in experimental acute lung injury, but their contribution to lung ischaemia-reperfusion injury post transplantation is unknown. OBJECTIVE: To define the role of donor intravascular monocytes in lung transplant-related acute lung injury and primary graft dysfunction. METHODS: Isolated perfused C57BL/6 murine lungs were subjected to warm ischaemia (2 hours) and reperfusion (2 hours) under normoxic conditions. Monocyte retention, activation phenotype and the effects of their depletion by intravenous clodronate-liposome treatment on lung inflammation and injury were determined. In human donor lung transplant samples, the presence and activation phenotype of monocytic cells (low side scatter, 27E10+, CD14+, HLA-DR+, CCR2+) were evaluated by flow cytometry and compared with post-implantation lung function. RESULTS: In mouse lungs following ischaemia-reperfusion, substantial numbers of lung-marginated monocytes remained within the pulmonary microvasculature, with reduced L-selectin and increased CD86 expression indicating their activation. Monocyte depletion resulted in reductions in lung wet:dry ratios, bronchoalveolar lavage fluid protein, and perfusate levels of RAGE, MIP-2 and KC, while monocyte repletion resulted in a partial restoration of the injury. In human lungs, correlations were observed between pre-implantation donor monocyte numbers/their CD86 and TREM-1 expression and post-implantation lung dysfunction at 48 and 72 hours. CONCLUSIONS: These results indicate that lung-marginated intravascular monocytes are retained as a 'passenger' leukocyte population during lung transplantation, and play a key role in the development of transplant-associated ischaemia-reperfusion injury.

Minimally Invasive Left Ventricular Assist Device Implantation: A Comparative Study.

Left ventricular assist device (LVAD) is now a routine therapy for advanced heart failure. Minimally invasive approach via thoracotomy for LVAD implantation is getting popular due to its potential advantage over the conventional sternotomy approach in terms of reduced risk at re-operation due to sternal sparing. We compared the approaches (thoracotomy and sternotomy) to determine the superiority. Minimally invasive approach involved fitting of the LVAD inflow cannula into left ventricle apex via left anterior thoracotomy and anastomosis of outflow graft to ascending aorta via right anterior thoracotomy. In the sternotomy approach, both the procedures were performed via sternotomy. Outcomes in patients after LVAD implantation were compared depending on these approaches for the surgery. Two hundred and five continuous flow LVAD implantations performed between July 2006 and June 2015 at a single center were divided based on surgical approach, that is, sternotomy (n = 180) and thoracotomy (n = 25) groups. There was no significant difference between the groups in relation to patient demographics, preoperative hemodynamic parameters, laboratory markers, or risk factors. There was no significant difference between the groups in terms of postoperative hemodynamic parameters, laboratory markers, bleeding and requirement of blood products, intensive care unit, and hospital stay or complications of LVAD surgery. There were no significant differences in terms of long-term survival (Log-Rank P = 0.953), however, thoracotomy, compared to sternotomy approach, incurred significantly less requirement of temporary right ventricular assist (4 vs. 19.4%, P = 0.041). Minimally invasive bilateral thoracotomy approach for LVAD implantation in addition to benefits of sternal sparing avoids dilatation of right ventricle and reduces chances of right ventricular failure requiring temporary right ventricular assist.

The novel αB-crystallin (CRYAB) mutation p.D109G causes restrictive cardiomyopathy.

Restrictive cardiomyopathy (RCM) is a rare heart disease characterized by diastolic dysfunction and atrial enlargement. The genetic etiology of RCM is not completely known. We identified by a next-generation sequencing panel the novel CRYAB missense mutation c.326A>G, p.D109G in a small family with RCM in combination with skeletal myopathy with an early onset of the disease. CRYAB encodes αB-crystallin, a member of the small heat shock protein family, which is highly expressed in cardiac and skeletal muscle. In addition to in silico prediction analysis, our structural analysis of explanted myocardial tissue of a mutation carrier as well as in vitro cell transfection experiments revealed abnormal protein aggregation of mutant αB-crystallin and desmin, supporting the deleterious effect of this novel mutation. In conclusion, CRYAB appears to be a novel RCM gene, which might have relevance for the molecular diagnosis and the genetic counseling of further affected families in the future.

Central Extracorporeal Life Support With Left Ventricular Decompression to Berlin Heart Excor: A Reliable "Bridge to Bridge" Strategy in Crash and Burn Patients.

The aim of this study was to compare patients with severe biventricular heart failure who underwent Berlin Heart Excor implantation with (cardiogenic shock [CS] status) or without the need for preoperative extracorporeal life support (ECLS) as a bridge to long-term device. A total of 40 consecutive patients with severe biventricular heart failure underwent Berlin Heart Excor implantation with (CS status, n = 20, 50%) or without (control, n = 20, 50%) the need for preoperative ECLS as a bridge to long-term device from March 2007 to May 2015 at our institution. Demographics and preoperative baseline characteristics as well as early and long-term outcomes including mortality and complication rates were retrospectively compared between the two groups. There were no statistically significant differences in terms of demographics and most preoperative clinical characteristics. The mean age in the ECLS (CS group) and control group was 43.5 ± 19.4 and 41.3 ± 16.4 (P = 0.705), whereas 20 and 25% of patients were females (P = 1.000). However, patients from the ECLS group had preoperatively higher lactate (P = 0.037), aspartate aminotransferase (P < 0.001), and alanine aminotransferase (P < 0.001) levels, all of them significantly decreased after surgery (P  = 0.004, P = 0.017, and P = 0.001, respectively) and did not show any statistical differences to the corresponding values from the control group (P = 0.597, P = 0.491, and P = 0.339, respectively). Postoperatively, patients from the control and ECLS groups had statistically similar incidences of liver failure (30 vs. 35%, P = 0.736), renal failure (45 vs. 70%, P = 0.110), need for reopening (35 vs. 60%, P = 0.113), major cerebrovascular events (35 vs. 30%, P = 0.736), sepsis (10 vs. 25%, P = 0.407), wound infection (20 vs. 30%, P = 0.716), abdominal ischemia requiring surgery (28.6 vs. 36.8%, P = 0.719), and acute respiratory distress syndrome (25 vs. 35.3%, P = 1.000). The proportion of patients who were bridged to transplantation was statistically similar between the ECLS and the control groups (40 vs. 52.6%, P = 0.429). Furthermore, there were no statistically significant differences in terms of early (Breslow [generalized Wilcoxon] P = 0.907) and long-term (log-rank [Mantel-Cox] P = 0.787) overall cumulative survival accounting for 30-day survival of 75 versus 75%, 6-month survival of 60 versus 55%, 1-year survival of 54 versus 40%, and 7-year survial of 47 versus 40% in the control and ECLS groups, respectively. ECLS in critical CS as a bridge to implantation of the Berlin Heart Excor ventricular assist device is safe and is associated with improvement in end-organ function leading to similar excellent early and long-term survival and incidences of major complications as in patients without the need for preoperative ECLS support.

Algorithms to guide ambulance clinicians in the management of emergencies in patients with implanted rotary left ventricular assist devices.

Advances in left ventricular assist device (LVAD) therapy have resulted in increasing numbers of adult LVAD recipients in the community. However, device failure, stroke, bleeding, LVAD thrombosis and systemic infection can be life-threatening emergencies. Currently, four LVAD systems are implanted in six UK transplant centres, each of which provides device-specific information to local emergency services. This has resulted in inconsistent availability and content of information with the risks of delayed or inappropriate decision-making. In order to improve patient safety, a consortium of UK healthcare professionals with expertise in LVADs developed universally applicable prehospital emergency algorithms. Guidance was framed as closely as possible on the standard ABCDE approach to the assessment of critically ill patients.

Veno-venous extracorporeal membrane oxygenation using an innovative dual-lumen cannula following implantation of a total artificial heart.

We report our first clinical use of the new Protek DuoTM cannula for peripheral veno-venous extra-corporeal life support (ECLS). A 53-year-old male patient underwent implantation of a total artificial heart (TAH) for biventricular failure. However, due to the development of post-operative respiratory dysfunction, the patient required ECLS for six days.

Escalation of extracorporeal life support as a bridge to lung transplantation in end-stage lung disease.

Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplant (LTx) is not uncommon, but it is not commonplace yet. We present a case of a 45-year-old man with cystic fibrosis with recent deterioration in lung function who was initially supported with veno-venous (VV) ECMO. However, he subsequently required conversion to veno-veno-arterial (VVA) ECMO. After 21 days of support, he underwent double lung transplantation, with an uneventful postoperative course. This case shows that, in patients with end-stage respiratory failure awaiting lung transplantation, extracorporeal life support may require escalation to improve gas exchange and address circulatory requirements.

Salvage myocardial revascularisation in spontaneous left main coronary artery dissection with cardiogenic shock - the role of mechanical circulatory support.

Spontaneous left main coronary artery dissection is a rare cause of acute coronary events or sudden cardiac death, constituting less than 1% of all epicardial coronary artery dissections. It is often fatal and is mostly recognized at post-mortem examination in young victims of sudden death. More than 70% of the reported cases occurred in women, particularly during pregnancy and the peripartum period and those on oral contraceptives. The clinical presentation is highly variable and prognosis varies widely, depending predominantly on the speed of diagnosis. Treatment options include medical therapy, revascularization with coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) and mechanical circulatory support in cases of cardiogenic shock. We report a case of spontaneous dissection of the left main stem coronary artery, with extension into the left coronary territory, which occurred in a 41-year-old lady, complicated by profound cardiogenic shock requiring recovery with extracorporeal mechanical circulatory support after salvage myocardial revascularization.

GORD symptoms in lung transplantation: how efficient is the reflux symptom index questionnaire compared to the esophageal impedance test?

OBJECTIVE: As Gastroesophageal reflux disease (GORD) affects long-term survival in lung transplant recipients, the aim of this observational prospective study was to analyze the efficacy of The Reflux Symptom Index Questionnaire (RSI) compared to the esophageal impedance test. METHODS: Both esophageal impedance studies and RSI questionnaire were routinely performed in all patients who had completed rehabilitation following lung transplantation from June 2013 till March 2014. RSI generates a score of between zero and forty-five, taking into account any symptoms within four wk of the questionnaire. Our analysis considered RSI score cut-offs of 10 and 13 indicating significance of reflux. RESULTS: Out of 84 patients, 50 (59.5%) had evidence of GORD detected by impedance studies, whereas only 33 (39.2%) and 22 (26.2%) had RSI >10 and 13, respectively. An elevated RSI was not found to be associated with positive impedance studies using a score of either 10 or 13 (p = 0.127 and p = 0.142, respectively); 32.1% (n = 27) and 40.5% (n = 34) were found to have negative RSI and positive impedance test using 10 or 13 as cut-off, respectively. CONCLUSION: RSI Score is an unreliable predictor of GORD among lung transplant recipients. The authors therefore recommend the routine use of impedance testing in post-transplant patients.

Effect of donor cardiac arrest and arrest duration on outcomes of lung transplantation.

BACKGROUND: Limited data are available about lung transplantation (LTx) from donors suffering cardiac arrest (CA) prior to actual donation. METHODS: A retrospective analysis of LTx performed between January 2007 and September 2012 was done with the focus on CA in donors. The recipients were grouped depending on the history of donor CA and CA duration (downtime) as: No cardiac arrest ("NoCA"), CA downtime less than 20 min ("CA < 20"), and CA downtime equal to or more than 20 min ("CA > 20"). Early and mid-term outcomes after LTx were compared among the three groups. RESULTS: A total of 237 LTx were performed during the study period. One hundred eighty-eight patients received organs from "NoCA" donors, 25 from "CA < 20" donors, and 24 patients from "CA > 20" donors. There was a trend toward better overall cumulative survival in both CA groups (log rank p = 0.076) whereas the survival in the "CA > 20" group was significantly better than in the "NoCA" group in the subgroup analysis (log rank p = 0.045). Freedom from bronchiolitis obliterans syndrome (BOS) also increased with increase in CA duration, although it did not reach statistical significance. CONCLUSIONS: Transplantation of lungs from donors with a history of CA is safe and feasible. Longer duration of cardiac arrest may improve the outcomes after the LTx in terms of survival and freedom from BOS.

The role of cardiopulmonary bypass in lung transplantation.

BACKGROUND: The risk-benefit for utilizing cardio-pulmonary bypass (CPB) in lung transplantation (LTx) remains debatable. This study compares outcomes after LTx utilizing different CPB strategies - elective CPB vs. off-pump vs. off-pump with unplanned conversion to CPB. METHODS: A total of 302 LTx performed over seven yr were divided into three groups: "off-pump" group (n = 86), "elective on-pump" group (n = 162), and "conversion" group (n = 54). The preoperative donor and recipient demographics and baseline characteristics and the postoperative outcomes were analyzed; 1:1 propensity score matching was used to identify patients operated upon using elective CPB who had risk profiles similar to those operated upon off-pump (propensity-matching 1) as well as those emergently converted from off-pump to CPB (propensity-matching 2). RESULTS: Preoperative group demographic characteristics were comparable; however, the "off-pump" patient group was significantly older. The "conversion" group had a significantly greater number of patients with primary pulmonary hypertension, pulmonary fibrosis, preoperative mechanical ventilation, and preoperative extracorporeal life support (ECLS). Postoperatively, patients from the "conversion" group had significantly poorer PaO2 /FiO2 ratios upon arrival in intensive care unit (ICU) and at 24, 48, and 72 h postoperatively, and they required more prolonged ventilation, longer ICU admission, and they experienced an increased need for ECLS than the other groups. Overall, cumulative survival at one, two, and three yr was significantly worse in patients from the "conversion" group compared to the "off-pump" and "elective on-pump" groups - 61.9% vs. 94.4% vs. 86.9%, 54.4% vs. 90.6% vs. 79.5% and 39.8% vs. 78.1% vs. 74.3%, respectively (p < 0.001). The "off-pump" group had significantly better PaO2 /FiO2 ratios, and a significantly shorter duration of ventilation, ICU stay, and hospital length of stay when compared to the propensity-matched "elective on-pump" group. There were no statistically significant differences in postoperative outcomes and overall survival between the "converted" group and the propensity-matched "elective on-pump" group. CONCLUSIONS: Despite segregation of unplanned CPB conversion cases from elective on-pump cases, patients with comparable preoperative demographic/risk profiles demonstrated better early postoperative outcomes and, possibly, an improved early survival with an off-pump strategy. A considerable proportion of high-risk patients require intraoperative conversion from off-pump to CPB, and this seems associated with suboptimal outcomes; however, there is no significant benefit to employing an elective on-pump strategy over emergent conversion in the high-risk group.

Investigation of the Characteristics of HeartWare HVAD and Thoratec HeartMate II Under Steady and Pulsatile Flow Conditions.

The aim of this study was to elucidate the dynamic characteristics of the Thoratec HeartMate II (HMII) and the HeartWare HVAD (HVAD) left ventricular assist devices (LVADs) under clinically representative in vitro operating conditions. The performance of the two LVADs were compared in a normothermic, human blood-filled mock circulation model under conditions of steady (nonpulsatile) flow and under simulated physiologic conditions. These experiments were repeated using 5% dextrose in order to determine its suitability as a blood analog. Under steady flow conditions, for the HMII, approximately linear inverse LVAD differential pressure (H) versus flow (Q) relationships were observed with good correspondence between the results of blood and 5% dextrose under all conditions except at a pump speed of 9000 rpm. For the HVAD, the corresponding relationships were inverse curvilinear and with good correspondence between the blood-derived and 5% dextrose-derived relationships in the flow rate range of 2-6 L/min and at pump speeds up to 3000 rpm. Under pulsatile operating conditions, for each LVAD operating at a particular pump speed, an counterclockwise loop was inscribed in the HQ domain during a simulated cardiac cycle (HQ loop); this showed that there was a variable phase relationship between LVAD differential pressure and LVAD flow. For both the HMII and HVAD, increasing pump speed was associated with a right-hand and upward shift of the HQ loop and simulation of impairment of left ventricular function was associated with a decrease in loop area. During clinical use, not only does the pressure differential across the LVAD and its flow rate vary continuously, but their phase relationship is variable. This behavior is inadequately described by the widely accepted representation of a plot of pressure differential versus flow derived under steady conditions. We conclude that the dynamic HQ loop is a more meaningful representation of clinical operating conditions than the widely accepted steady flow HQ curve.

Hybrid ECMO for a patient in respiratory failure developing cardiac insufficiency.

A 45-year-old patient in lung failure treated with veno-venous extracorporeal membrane oxygenation (VV ECMO) developed subsequent right heart failure and required cardiac support.We present a method of upgrading a VV ECMO to a hybrid system for simultaneous support for respiratory and cardiac failure.

Use of PTFE patch for pericardial closure after minimal invasive LVAD implantation.

The left ventricular assist device (LVAD) is now a routine therapy for advanced heart failure. The thoracotomy approach for LVAD implantation, in which the left ventricle is approached through a pericardial rent, is becoming popular. We demonstrate closure of the pericardial rent with a polytetrafluoroethylene (PTFE) patch and its advantages.