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.

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.

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.

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.

Oxygenator in short-term LVAD circuit: a rescue in post-LVAD pulmonary complications.

Pulmonary complications after left ventricular assist device (LVAD) implantation, though infrequent, can be potentially catastrophic. A 62-year-old female with cardiogenic shock, supported on short-term LVAD, developed pulmonary oedema. An oxygenator was introduced into the LVAD circuit, which improved the gas exchange and, eventually, after weaning off the oxygenator, the patient received long-term LVAD. The introduction of an oxygenator into the short-term LAVD circuit is a lifesaving manoeuvre in such a situation. It offers freedom of introducing and removing the oxygenator into the LVAD circuit without opening the chest and competing for LVAD flow.

Ex vivo heart perfusion after cardiocirculatory death; a porcine model.

BACKGROUND: Donation after cardiocirculatory death (DCD) has lead to an increase in organ availability. However, because of medical, logistic, and ethical issues, the use of hearts from DCD donors for transplantation is not generally considered to be feasible. In this study, we investigated the feasibility of ex vivo resuscitation and assessment of the porcine heart after circulatory death using the organ care system (OCS). METHODS: Cardiocirculatory death was induced in five pigs by cessation of mechanical ventilation. No heparin was administered. The agonal time (AT) was calculated as the time between a reduction of blood pressure <50 mm Hg or a fall in saturation beneath 70% and the cessation of electrical activity. After a further 15 min of warm ischemia, hearts were procured and implanted into the OCS, mimicking the actual clinical scenario for other organs. Thus, procured grafts were assessed ex vivo over a period of 4 h. RESULTS: Four hearts were successfully resuscitated on the system (AT 8, 15, 20, and 34 min) Three grafts had excellent visual contractility and lactate trends and were considered to be transplantable. One graft (AT 34 min) had an increased lactate and abnormal contractility being unsuitable for transplantation. One heart with 48-min AT could not be resuscitated. CONCLUSIONS: Our data show that hearts from nonheparinized DCD porcine donors can be successfully resuscitated using the OCS in a scenario, which closely simulates clinical conditions.

Lung transplantation in chronic obstructive pulmonary disease: long-term survival, freedom from bronchiolitis obliterans syndrome, and factors influencing outcome.

OBJECTIVES: Lung transplantation (LTx) remains the definitive treatment for end-stage lung failure, whereas chronic obstructive pulmonary disease (COPD) represents one of the main diagnoses leading to the indication for a transplant. We sought to assess long-term outcomes after LTx in patients diagnosed with COPD and analyze factors influencing outcome in this frequent patient cohort. METHODS: Between January 2007 and November 2013, a total of 88 LTx were performed in patients with COPD in our institution. Patients with emphysema associated with alpha1-antitrypsin deficiency were excluded from this observation. The study design was a retrospective review of the prospectively collected data. A large number of pre-, intra-, and postoperative variables were analyzed including long-term survival and freedom from bronchiolitis obliterans syndrome (BOS). Furthermore, impact of different variables on survival was analyzed. RESULTS: Preoperative donor data indicated a large proportion of marginal donors. While the overall cumulative survival after six yr was 57.4%, the results in terms of BOS-free survival in long-term follow-up were 39.7% after six yr. Patients with COPD were also associated with a low incidence (2.3%) of the need for postoperative extracorporeal life support (ECLS). CONCLUSIONS: Long-term results after LTx in patients with COPD are acceptable with excellent survival, freedom from BOS, and low use of ECLS postoperatively despite permanently increasing proportion of marginal organs used.

Minimally invasive access for central extracorporeal life support: how we do it.

Central extracorporeal life support (ECLS) is an effective treatment method of cardiogenic shock patients with or without lung failure. However, complications like infection and bleeding are common. The classical implantation approach requires full sternotomy, mobilization of the heart, with the well-known risks of bleeding and mediastinal infections. We present our minimally invasive technique for central ECLS through a nonsternotomy incision. Minimized right-sided thoracotomy is performed. Flexible arterial and venous cannulas are tunneled toward the right thoracotomy incision through the eighth intercostal space. A sewing ring is secured to the right atrium and a tube graft is anastomosed to the ascending aorta. Following full-dose heparinization, the arterial cannula is inserted with the tip into the vascular graft of the ascending aorta and the venous cannula via the ring into the right atrium. After meticulous deairing, the central ECLS is set at full flow.

Gender differences in continuous-flow left ventricular assist device therapy as a bridge to transplantation: a risk-adjusted comparison using a propensity score-matching analysis.

The purpose of this study was to evaluate gender differences regarding outcome after continuous-flow left ventricular assist device (cfLVAD) implantation. The study was a retrospective review of prospectively collected data. Included were 24 consecutive female cfLVAD recipients and 24 male recipients (62.5% HeartMate II, 37.5% HeartWare) who received their devices between July 2007 and May 2013. Subjects were matched using propensity score analysis based on age, diagnosis, body surface area, preoperative mechanical circulatory support, heart failure severity score (INTERMACS class), and comorbidities. Female patients were significantly sicker before operation. After propensity score matching, there were no statistically significant differences in demographics or clinical baseline characteristics between male and female LVAD recipients. Also, there was a trend towards a longer postoperative intensive care unit stay in the female group (median 9 days [interquartile range 5-17] versus 15 days [interquartile range 8-33]; P < 0.061) and higher postoperative bilirubin values (median 14 mmol/L [interquartile range 10-17] versus 21 mmol/L [interquartile range 13-30]). However, there were no significant differences between the two groups in terms of outcome (P < 0.569). The overall survival was comparable between the two groups (log rank P < 0.389). Half (50%) of female patients required inotropic support for more than 7 days compared with 21.7% in the male group (P < 0.048). Half (50%) of female recipients required short-term postoperative right ventricular assist device implantation compared with 16.7% in the male group (P < 0.014). In conclusion, cfLVAD implantation as a bridge to transplantation is associated with longer duration of inotropic support and higher requirement for postoperative mechanical right ventricular support in women with similar survival rates. Further studies are required to identify additional demographic and clinical factors that modulate outcomes and will enhance the ability to risk-stratify cfLVAD recipients.

Continuous-flow left ventricular assist device therapy in patients with preoperative hepatic failure: are we pushing the limits too far?

The purpose of this study was to evaluate the effects and outcome of continuous-flow left ventricular assist device (cf-LVAD) therapy in patients with preoperative acute hepatic failure. The study design was a retrospective review of prospectively collected data. Included were 42 patients who underwent cf-LVAD implantation (64.3% HeartMate II, 35.7% HeartWare) between July 2007 and May 2013 with preoperative hepatic failure defined as elevation of greater than or equal to two liver function parameters above twice the upper normal range. Mean patient age was 35 ± 12.5 years, comprising 23.8% females. Dilated cardiomyopathy was present in 92.9% of patients (left ventricular ejection fraction 17.3 ± 5.9%). Mean support duration was 511 ± 512 days (range: 2-1996 days). Mean preoperative laboratory parameters for blood urea nitrogen, serum creatinine, total bilirubin, and alanine aminotransferase were 9.5 ± 5.4 mg/dL, 110.3 ± 42.8 µmol/L, 51.7 ± 38.3 mmol/L, and 242.1 ± 268.6 U/L, respectively. All parameters decreased significantly 1 month postoperatively. The mean preoperative modified Model for Endstage Liver Disease excluding international normalized ratio score was 16.03 ± 5.57, which improved significantly after cf-LVAD implantation to 10.62 ± 5.66 (P < 0.001) at 7 days and 5.83 ± 4.98 (P < 0.001) at 30 days postoperatively. One-year and 5-year survival was 75.9 and 48.1%, respectively. 21.4% of the patients underwent LVAD explantation for myocardial recovery, 16.7% were successfully transplanted, and 7.1% underwent LVAD exchange for device failure over the follow-up period. Patients with preexisting acute hepatic failure are reasonable candidates for cf-LVAD implantation, with excellent rates of recovery and survival, suggesting that cf-LVAD therapy should not be denied to patients merely on grounds of "preoperative elevated liver enzymes/hepatopathy."

First experience with the Synergy Micro-Pump in patients in INTERMACS class 1-2 as a bridge to transplantation: pushing the limits?

The Synergy Micro-pump is the smallest implantable left ventricular assist device (LVAD) and provides partial flow support up to 4.25 L/min. It was shown that early intervention with this device can provide substantial benefits to patients with severe heart failure not yet sick enough for a full-support LVAD. However, as it can be inserted via small incisions with no need for sternotomy or cardiopulmonary bypass, it might be beneficial for selected high-risk patients. The aim of this study was to evaluate the efficacy of the Synergy Micro-pump in patients in INTERMACS class 1-2. From February 2012 to August 2013, 13 patients with severe heart failure were supported with the Synergy Pocket Micro-pump. Patients were divided into two groups according to INTERMACS class: the high-risk group (INTERMACS class 1-2) and the low-risk group (INTERMACS class 3-4). There were seven patients in INTERMACS class 1-2 and six in INTERMACS class 3-4. Patient demographics, perioperative characteristics, and postoperative outcomes were compared. There were no statistically significant differences in patient demographics, and mean support time was 108 ± 114 days in the high-risk group and 238 ± 198 days in the low-risk group. Also, there were no significant differences in perioperative characteristics or in the rate of postoperative adverse events. The overall survival was comparable between the two groups (one late death in each group, log-rank P = 0.608). Two patients from the high-risk group were upgraded to a full-support LVAD (P = 0.462) after 65 ± 84.9 days of mean support. One patient from the high-risk group and two patients from the low-risk group were successfully transplanted (P = 0.559). The use of the Synergy Micro-pump in INTERMACS 1-2 patients is feasible and is associated with similar postoperative outcome as in patients in INTERMACS 3-4. Carefully selected patients with severe heart failure could benefit due to the small size of the pump; however, further studies and medium-term follow-up are required.

Extracorporeal Life Support in "Awake" Patients as a Bridge to Lung Transplant.

BACKGROUND: Traditionally, patients on extracorporeal membrane oxygenation (ECMO) are sedated and mechanically ventilated, which increases risk of complications related to immobility and mechanical ventilation. The purpose of this study was to assess the feasibility and highlight the benefits of a bridge to lung transplant (LTx) using "awake ECMO" support. METHODS: The peripheral venovenous or venoarterial ECMO was implanted at a bedside. A retrospective study of patients undergoing LTx between January 2007 and March 2013 was performed. Outcomes in patients supported on ECMO as a bridge to LTx and kept "awake" (Group 1) were compared with the rest of the LTx patients (Group 2). RESULTS: In this period, 249 LTx were performed and in them 7 patients were bridged to LTx using "awake ECMO" strategy. Two patients were awake at ECMO implantation and throughout the therapy, and two patients were on ventilator support at the time of ECMO implantation who were extubated later and maintained awake until LTx. The remaining three patients were awake for some time during the ECMO. There was no statistically significant difference in most donor characteristics and recipient baseline characteristics as well as post-LTx parameters between the two groups. One-year survival estimate was not different between the groups: Group 1, 85.7% vs. Group 2, 86.3% (log rank p = 0.99). CONCLUSION: In end-stage lung disease, the ECMO can be commenced in "awake" patients and patients can be awakened on ECMO. The "awake ECMO" strategy may avoid complications related to mechanical ventilation, sedation, and immobilization and provide comparable outcomes in the high-risk LTx patients.

Around and around the merry-go-round: multiple implantations of short- and long-term ventricular assist devices in a patient with severe heart failure.

Multiple implantations of left ventricular assist devices over a period of three years were performed in a 17-year-old gentleman with non-ischaemic dilated cardiomyopathy and congestive cardiac failure. The first device (HeartMate II) was implanted as a bridge to transplantation. However, after few months of support the patient showed signs of myocardial recovery and the device was successfully explanted. After 2 years of uneventful follow-up, the patient's condition deteriorated requiring further mechanical support. Due to the elevated risk associated with a redo full-support LVAD implantation, we decided to implant a partial support device (Synergy CircuLite). Because of recurrent pump thrombosis requiring device exchange, the final weeks to transplantation were bridged with CentriMag short-term LVAD. After successful cardiac transplantation the patient required further temporary extracorporeal membrane oxygenation support which was weaned off and explanted on the fourth postoperative day. After further uncomplicated postoperative recovery the patient was discharged and has been doing well for 1 year of follow-up.

Utilization of a novel rib spreader for minimally invasive lung transplantation.

Rack-and-pinion-type stainless steel rib spreader was innovated by Truffier in 1914, which was modified by Finochietto to have fenestrated blades and a hand-cranked lever to both separate the arms in a staged fashion and lock them in place at each stop. Its Burford-Finochietto variants with replaceable blades are ubiquitous in open thoracic surgery. Fehling Surgical Instrument, Inc (Acworth, GA) introduced a modified rib spreader-an assembly of movable and adjustable blades, a mobile bridge and spreader arms, which owing to its adaptation of thoracotomy incision provides an optimum exposure without injuring the ribs. The spreader is indispensible in lung transplantation surgery performed especially through minimally invasive (bilateral limited anterolateral thoracotomies with intact sternum) approach.