Delayed detection programming significantly reduces inappropriate ICD therapies in patients with left-ventricular assist devices

Funding Acknowledgements

Type of funding sources: None.

Background

Implantation of a left ventricular assist device (LVAD) is an established therapy for end-stage heart failure, either as bridge to transplantation or as destination therapy. Virtually all LVAD patients carry an implantable cardioverter-defibrillator (ICD) for primary or secondary prevention. The risk of ventricular tachyarrhythmias is significant in LVAD patients, but so is the burden of supraventricular tachycardia and the ensuing risk of inappropriate ICD therapies. The present retrospective study sought to quantify the impact of standard ICD programming vs. a ICD programming with long detection delays on the occurrence of inappropriate ICD therapies.

Methods and results

We retrospectively identified 337 consecutive patients (292 male, mean age 54.2 ± 12.3 years) who received a continuous-flow LVAD at our institution. Median follow-up duration was 2.3 (IQR 1.3, 3.7) years. Heart failure etiology was ischemic cardiomyopathy in 155 patients (46.0 %) and non-ischemic dilated cardiomyopathy in 150 (44.5 %). Other etiologies accounted for 32 patients (9.4 %). ICDs implanted at the time of LVAD implantation were single chamber devices in 176 patients (52.2 %), dual chamber devices in 45 patients (13.4 %), and CRT-D in 116 patients (34.4 %)

A total of 2228 ICD-treated arrhythmia episodes occurred in 153 patients. 2066 (92.6 %) episodes were appropriate interventions for ventricular arrhythmias. 162 (7.3 %) treatments were inappropriate due to supraventricular tachyarrhythmias (n=115; 71.4 %), sinus tachycardia (n=15; 9.3 %) or oversensing (n=21; 12.9%). We retrospectively compared a standard programming (number of intervals for detection [NID] in the slowest therapy zone ≤ 40) and a long delay programming (NID > 40) and investigated the time to the first inappropriate therapy.

A total of 285 patients were programmed to NID ≤ 40 at the first ICD interrogation after LVAD implant, 47 were programmed to NID > 40. Therapies were inactive in the remaining 5 patients. Median NID was 30 (IQR 23, 35) in the standard programming group and 60 (IQR 50, 76) in the long delay group, with similar rates for detection (median cycle lengths 340 [IQR 330, 350] ms and 330 [IQR 322, 340] ms for standard and long delay, respectively). Long delay programming was associated with significantly higher freedom from inappropriate therapies during follow-up (Hazard ratio 0.14, p [log rank] 0.027). No significant difference was observed between groups with regard to time to first appropriate therapy.

Conclusion

A number of intervals for detection greater than 40 in the slowest therapy zone was associated with a significantly increased freedom from inappropriate therapies in this large retrospective single-center cohort of LVAD patients with an ICD and should be considered as the default ICD programming strategy in this population.

Wearable Cardioverter-Defibrillators following Cardiac Surgery-A Single-Center Experience

BACKGROUND

A wearable cardioverter-defibrillator (WCD) can terminate ventricular fibrillation and ventricular tachycardias via electrical shock and thus give transient protection from sudden cardiac death. We investigated its role after cardiac surgery.

METHODS

We retrospectively analyzed all patients who were discharged with a WCD from cardiac surgery department. The WCD was prescribed for patients with a left ventricular ejection fraction (LVEF) of ≤35% or an explanted implantable cardioverter-defibrillator (ICD).

RESULTS

A total of 100 patients were included in this study, the majority (n = 59) had received coronary artery bypass graft surgery. The median wearing time of a WCD patient was 23.5 hours per day. LVEF was 28.9 ± 8% after surgery and improved in the follow-up to 36.7 ± 11% (p < 0.001). Three patients were successfully defibrillated. Ten patients experienced ventricular tachycardias. No inappropriate shocks were given. An ICD was implanted in 25 patients after the WCD wearing period.

CONCLUSION

Ventricular arrhythmias occurred in 13% of the investigated patients. LVEF improved significantly after 3 months, and thus a permanent ICD implantation was avoided in several cases. Sternotomy did not impair wearing time of the WCD. A WCD can effectively protect patients against ventricular tachyarrhythmias after cardiac surgery.

The influence of less invasive ventricular assist device implantation on renal function

BACKGROUND

End-stage heart failure is associated with severe after-effects such as heart valve insufficiency, cardiac arrhythmias or end-organ dysfunctions. Renal failure or 'cardiorenal syndrome' is a critical end-organ disorder associated with advanced heart failure, which occurs due to low-output failure. Drug therapy or surgical interventions involving left ventricular assist device (LVAD) implantation may impede the progress of heart insufficiency and its after-effects including renal failure. In this study, we investigated the impact of a minimally invasive ventricular assist device implantation through upper hemisternotomy combined with anterolateral thoracotomy on renal function, in patients with perioperative renal failure.

METHODS

We analyzed data obtained from 103 patients (80 males, 23 females; mean age 53.8±11.7) who underwent LVAD implantation at our clinic within a 15-year interval (2001-2016) and were dialyzed due to renal dysfunction. 90 patients were operated with the conventional LVAD implantation technique (standard approach surgery, SAS) and 13 underwent less invasive approach implantation (less invasive surgery, LIS).

RESULTS

For all patients, data analysis showed significant increase of glomerular filtration rate (GFR) (44.2±56.48 mL/min; 95% CI: 33.81-55.28; P<0.001) along with a significant decrease in the levels of creatinine (-1.08±1.83 mg/dL; 95% CI: 0.75-1.46; P<0.001) and urea (-4.62±13.66 mmol/L; 95% CI: 1.95-7.29; P<0.001). There was a considerable difference in change of renal parameters in patients treated with LIS in comparison to patients who underwent SAS, which was however not statistically significant (GFR: P=0.494; creatinine: P=0.543; urea P=0.918).

CONCLUSIONS

LVAD implantation improves kidney function in patients with renal dysfunction. A considerable difference in the change of renal parameters was detected in patients with LIS as compared to SAS, which was not significant possibly due to the limited size of the patient cohort (n=13).

A new tool for an explantation strategy of HeartMate 3™ left ventricular assist device

Although rare, recovery of cardiac function after mechanical support of the left ventricle is the most desirable therapeutic goal in the treatment of end-stage heart failure.Herein, we present a novel implantable device for explantation of the HeartMate 3™ left ventricular assist device (LVAD) in patients, following cardiac recovery, avoiding (re-) sternotomy.This article demonstrates the feasibility of applying this novel device, which fits into the sewing ring of the LVAD.This custom-made mechanical plug offers a promising alternative to standard device-explantation procedures.

Left ventricular assist device exchange for the treatment of HeartMate II pump thrombosis

Background

Pump thrombosis is the most severe and acute complication of left ventricular assist device (LVAD) therapy and treatment remains challenging. Whilst lysis therapy is often not successful, the exchange of the occluded LVAD is currently the most applied therapeutic treatment for this event. With this study we examine the effects of minimal-invasive LVAD exchange on the rate re-thrombosis and outcomes as well as adverse events in the study group.

Methods

Between February 2004 and December 2015 more than 600 LVADs were implanted at our institution. We retrospectively studied a patient cohort of 41 patients who underwent LVAD exchange because of pump thrombosis at a single institution. Outcomes, rates of re-thrombosis and adverse events were analyzed.

Results

Between February 2004 and December 2015, 87 exchanges of LVADs were performed at a single center. In 41 cases pump thrombosis was the reason for LVAD exchange. A total of 28 patient years (10,276 days) were analyzed. Average ICU stay was 15.8±20.4 days and average in-hospital stay 38.1±37.3 days after LVAD exchange. After thirty days the survival rate was 80.5%, 75.6% after 6 months and 70.7% one year after LVAD exchange. Out of the study cohort, three patients have successfully undergone heart transplantation. Twelve patients suffered a stroke postoperatively (29%). Twelve patients needed postoperative dialysis (29%). No technical complications of the VAD were recorded in the study group. Two patients underwent successful LVAD explantation due to myocardial recovery. One year after LVAD exchange, 14 patients underwent re-exchange due to pump thrombosis (34%). Eight patients suffered from a LVAD related infection out of which two patients were treated by pump exchange. A total of 12 patients died during the complete one year follow up of this study (29%). Four patients died in the second, two in the third and one in the fourth year after LVAD exchange. The remaining 17 patients are still ongoing on the device.Conclusions: It is generally feasible to treat pump thrombosis via LVAD exchange. Yet, the exchange procedure is not without risk and the risk of re-thrombosis (34%), stroke (29%), postoperative dialysis (29%) and perioperative complications remains high.