Tobias Wengenmayer

Vector Selection of a Quadripolar Left Ventricular Pacing Lead Affects Acute Hemodynamic Response to Cardiac Resynchronization Therapy: A Randomized Cross-Over Trial

Background A suboptimal left ventricular (LV) pacing site may account for non-responsiveness of patients to cardiac resynchronization therapy (CRT). The vector selection of a novel quadripolar LV pacing lead, which was mainly developed to overcome technical issues with stimulation thresholds and phrenic nerve capture, may affect hemodynamic response, and was therefore assessed in this study. (German Clinical Trials Register DRKS00000573). Methods and Results Hemodynamic effects of a total of 145 LVPCs (9.1 per patient) of CRT devices with a quadripolar LV lead (Quartet™, St. Jude Medical) were assessed in 16/20 consecutive patients by invasive measurement of LV+dP/dtmax at an invasively optimized AV-interval in random order. Optimal (worst) LVPCs per patient were identified as those with maximal (minimal) %change in LV+dP/dtmax (%ΔLV+dP/dtmax) as compared to a preceding baseline. LV+dP/dtmax significantly increased in all 145 LVPCs (p<0.0001 compared to baseline) with significant intraindividual differences between LVPCs (p<0.0001). Overall, CRT acutely augmented %ΔLV+dP/dtmax by 31.3% (95% CI 24%–39%) in the optimal, by 21.3% (95% CI: 15%–27%) in the worst and by 28.2% (95% CI: 21%–36%) in a default distal LVPC. This resulted in an absolute additional acute increase in %ΔLV+dP/dtmax of 10.0% (95% CI: 7%–13%) of the optimal when compared to the worst (p<0.0001), and of 3.1% (95% CI: 1%–5%) of the optimal when compared to the default distal LVPC (p<0.001). Optimal LVPCs were not programmable with a standard bipolar lead in 44% (7/16) of patients. Conclusion The pacing configuration of a quadripolar LV lead determinates acute hemodynamic response. Pacing in the individually optimized configuration gives rise to an additional absolute 10% increase in %ΔLV+dP/dtmax when comparing optimal and worst vectors.

Cold ischaemic time and time after transplantation alter segmental myocardial velocities after heart transplantation

OBJECTIVES The aim of this study was to investigate changes in segmental, three-directional left ventricular (LV) velocities in patients after heart transplantation (Tx). METHODS Magnetic resonance tissue phase mapping was used to assess myocardial velocities in patients after Tx (n = 27) with normal LV ejection fraction (63 ± 5%) and those without signs of rejection. Regional wall motion and dyssynchrony were analysed in relation to cold ischaemic time (150 ± 57 min, median = 154 min), age of the donor heart (35 ± 13 years, median = 29 years), time after transplantation (32 ± 26 months, median = 31 months) and global LV morphology and function. RESULTS Segmental myocardial velocities were significantly altered in patients with cold ischaemic times >155 min resulting in an increase in peak systolic radial velocities (2 of 16 segments, P = 0.03-0.04) and reduced segmental diastolic long-axis velocities (5 of 16 segments, P = 0.01-0.04). Time after transplantation (n = 8 patients <12 months after Tx vs n = 19 >12 months) had a significant influence on systolic radial velocities (increased in 2 of 16 segments, P = 0.01-0.04) and diastolic long-axis velocities (reduced in 5 of 16 segments, P = 0.02-0.04). Correlation analysis and multiple regression revealed significant relationships of cold ischaemic time (R = -0.384, P = 0.048), the donor hearts age (β= 0.9, P = 0.01) and time from transplantation (β= -0.36, P = 0.03) with long-axis diastolic dyssynchrony. CONCLUSIONS Time after transplantation and cold ischaemic time strongly affect segmental systolic and diastolic motion in patients after Tx. The understanding of alterations in regional LV motion in the transplanted heart under stable conditions is essential in order to utilize this methodology in the future as a potentially non-invasive means of diagnosing transplant rejection.

Dual Antiplatelet Therapy (DAPT) versus No Antiplatelet Therapy and Incidence of Major Bleeding in Patients on Venoarterial Extracorporeal Membrane Oxygenation.

Aims Bleeding is a frequent complication in patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO). An indication for dual antiplatelet therapy due to coronary stent implantation is present in a considerable number of these patients. The objective of this retrospective study was to evaluate if dual antiplatelet therapy (DAPT) significantly increases the high intrinsic bleeding risk in patients on VA-ECMO. Methods and Results A total of 93 patients were treated with VA-ECMO between October 2010 and October 2013. Average time on VA-ECMO was 58.9 ± 1.7 hours. Dual antiplatelet therapy was given to 51.6% of all patients. Any bleeding was recorded in 60.2% of all patients. There was no difference in bleeding incidence in patients on DAPT when compared to those without any antiplatelet therapy including any bleeding (66.7% vs. 57.1%, p = 0.35), BARC3 bleeding (43.8% vs. 33.3%, p = 0.31) or pulmonary bleeding (16.7% vs. 19.0%, p = 0.77). This holds true after adjustment for confounders. Rate of transfusion of red blood cells were similar in patients with or without DAPT (35.4% vs. 28.6%, p = 0.488). Conclusions Bleeding on VA-ECMO is frequent. This registry recorded no statistical difference in bleeding in patients on dual antiplatelet therapy when compared to no antiplatelet therapy. When indicated, DAPT should not be withheld from VA ECMO patients.

Short-term heart and lung support: extracorporeal membrane oxygenation and extracorporeal life support

In the last few years, progress in engineering has helped to develop minimized systems for extracorporeal membrane oxygenation and circulatory support. However, despite progress in engineering, the use of these systems still requires a trained team with special skills to be a beneficial and safe tool in the care of critically ill patients. The described indications and proceedings are based on the daily experience of the Freiburg group using these systems both on site in our own hospital and for transport purposes from primary care hospitals into our center of maximum care. The aim of this review is to share our hands-on experience in urgent/emergent implantations and therefore contribute to the knowledge within the growing community of users in this specialized field of extracorporeal support.

Fatal air embolism as complication of percutaneous dilatational tracheostomy on venovenous extracorporeal membrane oxygenation, two case reports

BackgroundTracheostomy is recommended in case of prolonged mechanical ventilation. Therefore, most patients with an indication for venovenous extracorporeal membrane oxygenation (ECMO) will also have an indication for tracheostomy.Case presentationWe report 2 cases of fatal air embolism into the ECMO system as complication of percutaneous dilatational tracheostomy. Both patients had an AVALON ELITE® bi-caval cannula implanted draining blood from the vena cava superior and inferior.ConclusionSince there is limited safety data on this specific group of patients, a routine early dilatational tracheostomy might be associated with a significant risk.

Severe mitral regurgitation requiring ECMO therapy treated by interventional valve reconstruction using the MitraClip

Surgical repair is considered the gold standard in severe mitral valve regurgitation. Multi‐organ failure because of acute mitral insufficiency, however, can be challenging to manage as it aggravates to an inoperable state. We report the case of a 59 year old woman who presented with pulmonary oedema because of high grade mitral regurgitation. A recompensation prior to surgery using medical therapy failed and the patient developed a progressive multi‐organ failure including pulmonary, circulatory, and renal failure within days. Symptomatically, our patient could be stabilized employing an extracorporeal membrane oxygenation and an intra‐aortic balloon pump. A surgical mitral valve repair was ruled out because of the multi‐organ failure. We performed an interventional valve reconstruction using the MitraClip™ device continuing the extracorporeal membrane oxygenation and the intra‐aortic balloon counterpulsation therapy during the procedure. After clipping, multi‐organ failure regressed and the extracorporeal membrane oxygenation could be explanted at day two after intervention.

Duration of extracorporeal membrane oxygenation is a poor predictor of hospital survival.

PURPOSE Venovenous extracorporeal membrane oxygenation (ECMO) is increasingly used in patients with respiratory failure. In patients without the option of lung transplantation, prognostication is challenging. We hypothesized that duration of ECMO therapy is inversely correlated with the chance of recovery and therefore hospital survival. MATERIALS AND METHODS A single-center retrospective register analysis was performed. All bridge-to-recovery venovenous ECMO patients without option for lung transplantation treated between October 2010 and September 2015 were included. FINDINGS A total of 175 patients (mean age, 51.61 ± 2.11 years) were detected. Medium time on ECMO was 9.26 ± 1.91 days. Time on ECMO was not significantly shorter in survivors compared to nonsurvivors (8.23 ± 2.04 and 10.15 ± 3.07, respectively; P = .327). Rate of hospital survival and time on ECMO did not correlate (P = .103). The predictive value of ECMO duration on hospital survival was 0.503 in a receiver operating characteristic analysis. CONCLUSIONS According to our registry data, duration of ECMO therapy by itself could not predict hospital survival. Prospective studies are needed to confirm this finding.

Four situations in which ECMO might have a chance.

Dear Editor, With great interest we read the article by Matthieu Schmidt and coworkers entitled “Ten situations in which ECMO is unlikely to be successful” pointing out contraindications for extracorporeal therapies [1]. As the number of applied extracorporeal membrane oxygenation (ECMO) systems is increasing steadily [2], a discussion about contraindications is much needed. Unfortunately, evidence from randomized controlled trials to support the discussion is low. Expert opinions like the ones presented by Schmidt et al. therefore provide necessary guidance. While we completely agree on most of the points presented, we would like to comment on others.

Unprotected Left Main Percutaneous Coronary Intervention in Acute Coronary Syndromes with Extracorporeal Life Support Backup

Background. Left main PCI is superior to coronary bypass surgery in selected patients. Registry data, however, suggest significant early adverse event rates associated with unprotected left main PCI. We aimed to evaluate safety of an extracorporeal life support (ECLS) as backup system during PCI. Methods. We report a registry study of 16 high-risk patients presenting with acute coronary syndromes undergoing unprotected left main PCI with an ECLS backup. Results. Seven patients (43.8%) presented with an acute myocardial infarction while 9 patients (56.3%) had unstable angina. Unprotected left main PCI could be successfully performed in all 16 patients. Mortality or thromboembolic event rates were zero within the index hospital stay. General anesthesia was necessary only in 5 patients (31.3%). Access site bleeding requiring transfusion was encountered in 4 patients (25.0%). Three patients (18.8%) developed access site complications requiring surgical intervention. All patients were ECLS-free after 96 hours. Conclusions. Unprotected left main PCI could be safely and effectively performed after ECLS implantation as backup in acute coronary syndromes in our patient collectively. Vascular access site complications however need to be considered when applying ECLS as backup system.

Recurrent pulseless electrical activity in a patient with coronary vasospasm and supravalvular aortic stenosis: a case report

BackgroundPulseless electrical activity cardiac arrest is associated with poor outcomes and the identification of potentially reversible reasons for cardiac arrest is fundamental.Case presentationWe describe the case of a 46-year-old male with the rare coincidental finding of supravalvular aortic stenosis and coronary vasospasm leading to recurrent pulseless electrical activity cardiac arrest. Extracorporeal life support was successfully applied for hemodynamic stabilization. Supravalvular aorticstenosis underwent surgical repair. The patient survived five time resuscitation and was discharged after full neurological recovery.ConclusionsCoronary vasospasm and supravalvular aortic stenosis are rare but potentially reversible causes of pulseless electrical activity cardiac arrest. Extracorporeal life support allows accurate diagnostic and possibly therapy even of uncommon reasons for cardiac arrest.