Pump delay or failure to restart

Medtronic issued notifications titled “urgent medical device communication” in December 2020, May 2021, December 2021, October 2022, August 2023, and April 2024 to advise that an identified subpopulation (defined as subgroups 1, 2, and 3) of HVAD™ systems may experience a delay or failure to restart at a higher rate than the overall population of HVAD™ systems. Pumps that are outside of the subpopulation are referred to as the general population.

A pump delay or failure to restart is linked to an interaction between the impeller and the top housing. Changes in the impeller or housing curvature may cause contact between the impeller and housing in a way that may make it more difficult for a pump to restart due to increased friction. It is important to note that this issue does not cause a running HVAD™ pump to stop; rather, the pump may fail to restart after a pump stop event, such as a controller exchange.

Table 1 below presents the cumulative probabilities of experiencing a pump stop resulting in either a delay or failure to restart, or a delay or failure to restart leading to a device exchange, decommission, or death by three (3) years. Tables 2 and 3 summarize pump populations, observed events of delay or failure to restart, and adverse events in subgroups 1, 2, and 3. Tables 1, 2, and 3 reflect updated failure or delay to restart data as of November 2024; however, patients on support data was last collected in August 2024.

Table 1: Cumulative probabilities for each subgroup and the general population by 3 years

Group Patient on support globally Cumulative probability of experiencing a pump stop resulting in delay or failure to restart (by 3 years) Cumulative probability of experiencing a device exchange, decommission, or death due to a delay or failure to restart (by 3 years)
Subgroup 1  22 2.7% 1.4%
Subgroup 2 11 31.0% 27.0%
Subgroup 3
 -190 5.0% 3.5%
General population exluding subgroups -1,376 0.5% 0.2%

 

Table 2: Cumulative event data by pump population

Group # of Pumps Distributed Cumulative Event Total Related Death Events
Subgroup 1  316 13 4
Subgroup 2 174 47 14
Subgroup 3
 1,026 49 16
General population 21,511 173 38
Totals 23,027 282 67

 

Table 3: Total number of events categorized for Subgroups 1, 2 and 3

Category # of Events
Death 34
Reoperation with VAD exchange 21
VAD Thrombus 1
Intraoperative Pump Exchange 7
Cardiac Arrest 1
Hospitalization 16
Worsening Heart Failure 1
Neurological 2
Hypoperfusion 1
Asymptomatic VAD stop event 25
Total # of Events 109

 

Pump weld

In April 2022 and July 2022, Medtronic issued notifications titled “Urgent Medical Device Correction” about a pump weld non-conformance with the HVAD™ System. The pump weld non-conformance causes the impeller to rotate non-concentrically and contact the center post of the pump, consistent with corrosion of the center post magnet. Patients with affected devices may present with signs and symptoms that resemble pump thrombus.

The table below provides a summary of the seven confirmed complaints provided to Medtronic as of November 2024. In all seven instances, suspected thrombus, high watt alarms, and grinding noises were consistently reported.

Complaint ID Manufacturing Date Implant Duration Reported Signs and Symptoms
1 Dec 2017 25 months
  • Suspected thrombus
  • High watt alarms
  • Grinding sounds
  • Vibration
  • Reported patient symptoms: fatigue, light-headedness and dizziness, shortness of breath
2 Jan 2018 28 Months
  • Suspected thrombus
  • Grinding sounds
  • High watt alarms
  • Elevated LDH level
  • Reported patient symptoms: dark urine
3 Jan 2018 72 Months
  • Low flow alarms
  • High watt alarms
  • Grinding noises
  • Patient did not have any abnormal symptoms or complications
4 April 2018 37 Months
  • Suspected thrombus
  • Grinding sounds
  • High watt alarms
  • Vibration
  • Patient symptoms not reported
5 May 2018 26 Months
  • Suspected thrombus
  • Grinding sounds
  • High watt alarms
  • Elevated LDH level
  • Patient symptoms not reported
6 May 2018 Not Reported
  • Suspected thrombus
  • Grinding sounds
  • High watt alarms
  • Patient symptoms not reported
7 April 2019 30 Months
  • Suspected thrombus
  • Grinding sounds
  • High watt alarms
  • Low flow alarms
  • Elevated LDH level
  • Patient symptoms not reported