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Micra Transcatheter Pacing Study

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ClinicalTrials.gov Identifier: NCT02004873
Recruitment Status : Completed
First Posted : December 9, 2013
Results First Posted : January 5, 2017
Last Update Posted : January 17, 2018
Sponsor:
Information provided by (Responsible Party):
Medtronic Cardiac Rhythm and Heart Failure

Study Type Interventional
Study Design Allocation: N/A;   Intervention Model: Single Group Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Condition Class I or II Indication for Implantation of a Single Chamber Ventricular Pacemaker According to ACC/AHA/HRS 2001 Guidelines and Any National Guidelines
Intervention Device: Micra Pacemaker Implant
Enrollment 744
Recruitment Details The study enrolled 744 subjects at 56 centers in 19 countries worldwide between December 2013 and May 2015.
Pre-assignment Details Of the 744 subjects enrolled, 19 exited from the study without attempting Micra implant (7 did not meet inclusion / exclusion criteria, 12 due to other miscellaneous reasons), 6 attempted Micra implant but were unsuccessful, and the remaining 719 subjects were successfully implanted with a Micra device.
Arm/Group Title Micra Pacemaker Implant
Hide Arm/Group Description All subjects who attempted Micra implant procedure
Period Title: Overall Study
Started 725 [1]
Micra Implant Success 719
Completed 301 [2]
Not Completed 424
Reason Not Completed
Implant unsuccessful             6
Awaiting 6-month visit             390
Missed 6-month visit             4
Death             23
Withdrawal by Subject             1
[1]
Micra Implant Attempt
[2]
6-Month Follow-up
Arm/Group Title Micra Study Enrollments
Hide Arm/Group Description All subjects enrolled in the Micra study
Overall Number of Baseline Participants 744
Hide Baseline Analysis Population Description
All subjects enrolled in the study
Age, Continuous  
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 744 participants
75.7  (11.0)
Sex/Gender, Customized  
Measure Type: Number
Unit of measure:  Participants
Number Analyzed 744 participants
Female 309
Male 434
Missing 1
Region of Enrollment  
Measure Type: Number
Unit of measure:  Participants
Number Analyzed 744 participants
Hungary 56
United States 297
Japan 38
United Kingdom 30
Malaysia 21
Spain 54
India 19
Greece 5
Canada 15
Austria 50
Czech Republic 43
Netherlands 37
China 7
Denmark 3
Italy 17
South Africa 3
Serbia 7
France 38
Australia 4
1.Primary Outcome
Title Major Complications
Hide Description Micra system and/or procedure related major complication free rate at 6-months post-implant.
Time Frame Implant to 6 Months Post Implant
Hide Outcome Measure Data
Hide Analysis Population Description
All subjects who attempted Micra implant procedure
Arm/Group Title Micra Pacemaker Implant
Hide Arm/Group Description:
All subjects who attempted Micra implant procedure
Overall Number of Participants Analyzed 725
Measure Type: Number
Number (98.66% Confidence Interval)
Unit of Measure: Kaplan-Meier survival probability (%)
96.0
(93.3 to 97.6)
Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Micra Pacemaker Implant
Comments

Null hypothesis: Major complication free rate at 6 months post-implant is less than or equal to 83%.

Alternative hypothesis: Major complication free rate at 6 months post-implant is greater than 83%.

Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments The threshold for statistical significance was 0.0067, determined by the pre-specified alpha spending function for the interim analysis.
Method z-test, 1-sided
Comments [Not Specified]
Method of Estimation Estimation Parameter Kaplan-Meier survival probability (%)
Estimated Value 96.0
Confidence Interval (2-Sided) 98.66%
93.3 to 97.6
Estimation Comments

The major complication free rate (i.e. survival probability) was estimated using the Kaplan-Meier method.

The coverage level for the confidence interval was 98.66%, determined by the pre-specified alpha spending function for the interim analysis.

2.Primary Outcome
Title Pacing Capture Threshold
Hide Description Subjects that have an adequate pacing capture threshold (PCT) at the 6-month post-implant visit, which is defined as PCT <=2 volts at 0.24 ms pulse width and the increase in PCT from implant to 6 months <=1.5 volts. The pacing capture threshold is the minimal electrical stimulus required to produce consistent cardiac depolarization. It is the minimum amount of energy that is required for a pacemaker to pace the heart.
Time Frame 6 Months Post Implant
Hide Outcome Measure Data
Hide Analysis Population Description
Subjects implanted with Micra who had paired implant and 6-month auto decrement PCT values (at 0.24 ms), or who had a system modification or alternative device implant prior to 6 months due to elevated threshold.
Arm/Group Title Micra Subjects With Implant and 6-month PCT Data
Hide Arm/Group Description:
Subjects implanted with Micra who had paired implant and 6-month auto decrement PCT values (0.24 ms), or who had a system modification or alternative device implant prior to 6 months due to elevated threshold.
Overall Number of Participants Analyzed 297
Measure Type: Number
Unit of Measure: participants
292
Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Micra Subjects With Implant and 6-month PCT Data
Comments

Null hypothesis: Percentage of subjects with an adequate pacing capture threshold at 6-months post-implant is less than or equal to 80%.

Alternative hypothesis: Percentage of subjects with an adequate pacing capture threshold at 6-months post-implant is greater than 80%.

Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments The threshold for statistical significance was 0.0067, determined by the pre-specified alpha spending function for the interim analysis.
Method Exact Binomial test
Comments [Not Specified]
Method of Estimation Estimation Parameter Percentage of subjects (%)
Estimated Value 98.3
Confidence Interval (2-Sided) 98.66%
95.4 to 99.6
Estimation Comments The coverage level for confidence interval was 98.66%, determined by the pre-specified alpha spending function for the interim analysis.
3.Secondary Outcome
Title Ventricular Capture Management Threshold
Hide Description Subjects that have a ventricular capture management threshold (VCMT) that is within 0.5 Volts of the manual (auto decrement) PCT (at 0.24 ms pulse width) at the 6-month post-implant visit. The VCMT is an automatically measured pacing capture threshold that is measured by the Micra device's pacing algorithm. In contrast, the manual (auto decrement) pacing capture threshold is measured by the clinician during a study visit.
Time Frame 6 Months Post Implant
Hide Outcome Measure Data
Hide Analysis Population Description
Subjects implanted with Micra who had paired ventricular capture management PCT and auto decrement PCT data available at the 6-month visit.
Arm/Group Title Micra Subjects With 6-month PCT Data
Hide Arm/Group Description:
Subjects implanted with Micra who had paired ventricular capture management PCT and auto decrement PCT data available at the 6-month visit.
Overall Number of Participants Analyzed 280
Measure Type: Number
Unit of Measure: participants
279
Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Micra Subjects With 6-month PCT Data
Comments

Null hypothesis: Percentage of subjects with VCMT within 0.5 Volts of auto decrement PCT at 6 months post-implant is less than or equal to 85%.

Alternative hypothesis: Percentage of subjects with VCMT within 0.5 Volts of auto decrement PCT at 6 months post-implant is greater than 85%.

Type of Statistical Test Superiority or Other
Comments [Not Specified]
Statistical Test of Hypothesis P-Value <0.0001
Comments Holm adjustment for multiple comparisons for secondary objectives was used. The threshold for statistical significance was 0.0067, determined by the pre-specified alpha spending function for the interim analysis.
Method Exact Binomial test
Comments [Not Specified]
Method of Estimation Estimation Parameter Percentage of subjects (%)
Estimated Value 99.6
Confidence Interval (2-Sided) 98.66%
97.5 to 100.0
Estimation Comments The coverage level for confidence interval was 98.66%, determined by the pre-specified alpha spending function for the interim analysis.
4.Secondary Outcome
Title Rate Response Operation of Micra
Hide Description Assessment of whether the Micra sensor-indicated rate derived from the input of the accelerometer during the Minnesota Pacemaker Response Exercise Protocol (M-PREP) treadmill test conducted at the 3-month and 6-month follow-up visits was proportional to the workload. The sensor-indicated rate (in min^-1) and workload (in METS) were normalized for each subject relative to their minimum and maximum possible values so the normalized values have a minimum possible value of zero and a maximum possible value of 1. These normalized values were used in a random effect linear regression model to assess the relationship between the sensor-indicated rate and workload via estimation of the Kay-Wilkoff slope parameter. The tests at 3-month and 6-month visits were combined in one analysis.
Time Frame 3 Months and 6 Months Post Implant (combined analysis)
Hide Outcome Measure Data
Hide Analysis Population Description
Subjects implanted with Micra who had usable M-PREP test(s) at 3-month and/or 6-month visits.
Arm/Group Title Micra Subjects With Usable M-PREP Data
Hide Arm/Group Description:
Subjects implanted with Micra who had usable M-PREP test(s) at 3-month and/or 6-month visits.
Overall Number of Participants Analyzed 20
Overall Number of Units Analyzed
Type of Units Analyzed: M-PREP tests
30
Mean (90% Confidence Interval)
Unit of Measure: regression slope parameter
0.864
(0.768 to 0.961)
Hide Statistical Analysis 1
Statistical Analysis Overview Comparison Group Selection Micra Subjects With Usable M-PREP Data
Comments Null hypothesis: Kay-Wilkoff slope parameter is < 0.65 or > 1.35 Alternative hypothesis: Kay-Wilkoff slope parameter is between 0.65 and 1.35
Type of Statistical Test Non-Inferiority or Equivalence
Comments The equivalence margin is 0.35. The Micra sensor indicated rate is considered proportional to the workload if the 90% CI for the Kay-Wilkoff slope parameter falls into [0.65, 1.35].
Statistical Test of Hypothesis P-Value <0.001
Comments Holm adjustment for multiple comparisons for secondary objectives was used. Two One-sided Test (TOST) procedure was used at the 0.05 significance level.
Method t-test, 1 sided
Comments Two One-sided Test (TOST)
Method of Estimation Estimation Parameter Slope
Estimated Value 0.864
Confidence Interval (2-Sided) 90%
0.768 to 0.961
Estimation Comments A random effect linear regression model was used to assess if the Micra sensor-indicated rate was proportional to the workload using the Kay-Wilkoff model. The Kay-Wilkoff slope parameter was estimated along with its 90% CI.
Time Frame From implant attempt to last subject follow-up, ranging from 0 to 14.5 months
Adverse Event Reporting Description [Not Specified]
 
Arm/Group Title Micra Pacemaker Implant
Hide Arm/Group Description All subjects who attempted Micra implant procedure
All-Cause Mortality
Micra Pacemaker Implant
Affected / at Risk (%)
Total   --/--    
Hide Serious Adverse Events
Micra Pacemaker Implant
Affected / at Risk (%) # Events
Total   226/725 (31.17%)    
Blood and lymphatic system disorders   
Anaemia * 1  4/725 (0.55%)  4
Heparin-induced thrombocytopenia * 1  1/725 (0.14%)  1
Leukocytosis * 1  1/725 (0.14%)  1
Normochromic normocytic anaemia * 1  1/725 (0.14%)  1
Splenic infarction * 1  1/725 (0.14%)  1
Thrombocytopenia * 1  1/725 (0.14%)  1
Cardiac disorders   
Acute myocardial infarction * 1  6/725 (0.83%)  6
Angina pectoris * 1  4/725 (0.55%)  4
Angina unstable * 1  2/725 (0.28%)  2
Aortic valve stenosis * 1  2/725 (0.28%)  2
Atrial fibrillation * 1  13/725 (1.79%)  13
Atrial flutter * 1  1/725 (0.14%)  1
Atrioventricular block complete * 1  5/725 (0.69%)  5
Bundle branch block right * 1  1/725 (0.14%)  1
Cardiac arrest * 1  1/725 (0.14%)  1
Cardiac failure * 1  52/725 (7.17%)  64
Cardiac perforation * 1  3/725 (0.41%)  3
Coronary artery disease * 1  5/725 (0.69%)  5
Coronary artery stenosis * 1  1/725 (0.14%)  1
Palpitations * 1  1/725 (0.14%)  1
Pericardial effusion * 1  11/725 (1.52%)  11
Pericarditis * 1  1/725 (0.14%)  1
Pulseless electrical activity * 1  1/725 (0.14%)  1
Supraventricular tachycardia * 1  1/725 (0.14%)  1
Tachycardia induced cardiomyopathy * 1  1/725 (0.14%)  1
Torsade de pointes * 1  1/725 (0.14%)  1
Ventricular fibrillation * 1  3/725 (0.41%)  3
Ventricular tachycardia * 1  3/725 (0.41%)  3
Congenital, familial and genetic disorders   
Ventricular septal defect * 1  1/725 (0.14%)  1
Ear and labyrinth disorders   
Vertigo * 1  2/725 (0.28%)  2
Endocrine disorders   
Hyperthyroidism * 1  1/725 (0.14%)  1
Eye disorders   
Cataract * 1  1/725 (0.14%)  1
Gastrointestinal disorders   
Abdominal pain upper * 1  1/725 (0.14%)  1
Diarrhoea * 1  2/725 (0.28%)  2
Diverticulum intestinal * 1  1/725 (0.14%)  1
Gastritis haemorrhagic * 1  1/725 (0.14%)  1
Gastrointestinal haemorrhage * 1  3/725 (0.41%)  3
Impaired gastric emptying * 1  1/725 (0.14%)  1
Inguinal hernia * 1  2/725 (0.28%)  2
Intestinal ischaemia * 1  1/725 (0.14%)  1
Intestinal obstruction * 1  1/725 (0.14%)  1
Rectal haemorrhage * 1  1/725 (0.14%)  1
Subileus * 1  1/725 (0.14%)  1
General disorders   
Asthenia * 1  1/725 (0.14%)  1
Chest pain * 1  1/725 (0.14%)  1
Coronary artery restenosis * 1  1/725 (0.14%)  1
Death * 1  1/725 (0.14%)  1
Device dislocation * 1  1/725 (0.14%)  1
Device pacing issue * 1  1/725 (0.14%)  1
Multi-organ failure * 1  2/725 (0.28%)  2
Non-cardiac chest pain * 1  8/725 (1.10%)  8
Pacemaker syndrome * 1  3/725 (0.41%)  3
Hepatobiliary disorders   
Cholecystitis * 1  1/725 (0.14%)  1
Cholelithiasis * 1  2/725 (0.28%)  2
Infections and infestations   
Arthritis bacterial * 1  1/725 (0.14%)  1
Bacteraemia * 1  2/725 (0.28%)  2
Bronchitis * 1  2/725 (0.28%)  2
Bronchopneumonia * 1  1/725 (0.14%)  1
Cellulitis * 1  3/725 (0.41%)  3
Clostridium difficile infection * 1  2/725 (0.28%)  2
Endocarditis * 1  2/725 (0.28%)  2
Epiglottitis * 1  1/725 (0.14%)  1
Gastritis viral * 1  1/725 (0.14%)  1
Gastroenteritis * 1  1/725 (0.14%)  1
Infected seroma * 1  1/725 (0.14%)  1
Influenza * 1  3/725 (0.41%)  3
Neutropenic sepsis * 1  1/725 (0.14%)  1
Osteomyelitis * 1  1/725 (0.14%)  1
Pneumonia * 1  19/725 (2.62%)  19
Pyelonephritis acute * 1  1/725 (0.14%)  1
Sepsis * 1  6/725 (0.83%)  6
Septic shock * 1  3/725 (0.41%)  4
Sinusitis * 1  1/725 (0.14%)  1
Staphylococcal bacteraemia * 1  1/725 (0.14%)  1
Urinary tract infection * 1  8/725 (1.10%)  8
Injury, poisoning and procedural complications   
Abdominal injury * 1  1/725 (0.14%)  1
Cardiac valve rupture * 1  1/725 (0.14%)  1
Dialysis related complication * 1  2/725 (0.28%)  2
Femoral neck fracture * 1  1/725 (0.14%)  1
Femur fracture * 1  1/725 (0.14%)  1
Incision site haemorrhage * 1  3/725 (0.41%)  3
Laceration * 1  2/725 (0.28%)  2
Medication error * 1  1/725 (0.14%)  1
Rib fracture * 1  1/725 (0.14%)  1
Spinal compression fracture * 1  1/725 (0.14%)  1
Subdural haematoma * 1  1/725 (0.14%)  1
Subdural haemorrhage * 1  2/725 (0.28%)  2
Tracheostomy malfunction * 1  1/725 (0.14%)  1
Upper limb fracture * 1  1/725 (0.14%)  1
Vascular pseudoaneurysm * 1  2/725 (0.28%)  2
Investigations   
International normalised ratio increased * 1  2/725 (0.28%)  2
Metabolism and nutrition disorders   
Dehydration * 1  2/725 (0.28%)  2
Fluid overload * 1  1/725 (0.14%)  1
Gout * 1  1/725 (0.14%)  1
Hyperglycaemia * 1  1/725 (0.14%)  1
Hypoglycaemia * 1  1/725 (0.14%)  1
Hyponatraemia * 1  1/725 (0.14%)  1
Metabolic acidosis * 1  1/725 (0.14%)  1
Musculoskeletal and connective tissue disorders   
Arthralgia * 1  1/725 (0.14%)  1
Axillary mass * 1  1/725 (0.14%)  1
Osteoarthritis * 1  2/725 (0.28%)  2
Neoplasms benign, malignant and unspecified (incl cysts and polyps)   
Adenocarcinoma of colon * 1  2/725 (0.28%)  2
Bladder cancer * 1  1/725 (0.14%)  1
Breast cancer metastatic * 1  1/725 (0.14%)  1
Ovarian cancer metastatic * 1  1/725 (0.14%)  1
Rectosigmoid cancer * 1  1/725 (0.14%)  1
Squamous cell carcinoma * 1  1/725 (0.14%)  1
Nervous system disorders   
Cerebrovascular accident * 1  2/725 (0.28%)  2
Cognitive disorder * 1  1/725 (0.14%)  1
Convulsion * 1  2/725 (0.28%)  2
Dementia * 1  1/725 (0.14%)  1
Dizziness * 1  1/725 (0.14%)  1
Epilepsy * 1  1/725 (0.14%)  1
Headache * 1  1/725 (0.14%)  1
Ischaemic stroke * 1  1/725 (0.14%)  1
Presyncope * 1  8/725 (1.10%)  8
Syncope * 1  7/725 (0.97%)  7
Transient ischaemic attack * 1  2/725 (0.28%)  2
Vertebrobasilar insufficiency * 1  1/725 (0.14%)  1
Vocal cord paralysis * 1  1/725 (0.14%)  1
Psychiatric disorders   
Mental status changes * 1  1/725 (0.14%)  1
Renal and urinary disorders   
Haematuria * 1  1/725 (0.14%)  1
Renal failure * 1  2/725 (0.28%)  2
Renal failure acute * 1  4/725 (0.55%)  4
Renal failure chronic * 1  3/725 (0.41%)  3
Urinary retention * 1  3/725 (0.41%)  3
Reproductive system and breast disorders   
Prostatitis * 1  1/725 (0.14%)  1
Respiratory, thoracic and mediastinal disorders   
Acute respiratory failure * 1  2/725 (0.28%)  2
Chronic obstructive pulmonary disease * 1  3/725 (0.41%)  3
Dyspnoea * 1  3/725 (0.41%)  3
Interstitial lung disease * 1  1/725 (0.14%)  1
Pleural effusion * 1  3/725 (0.41%)  3
Pneumonia aspiration * 1  2/725 (0.28%)  2
Pulmonary embolism * 1  4/725 (0.55%)  4
Pulmonary oedema * 1  1/725 (0.14%)  1
Respiratory arrest * 1  1/725 (0.14%)  1
Respiratory distress * 1  1/725 (0.14%)  1
Respiratory failure * 1  1/725 (0.14%)  1
Skin and subcutaneous tissue disorders   
Dermatitis allergic * 1  1/725 (0.14%)  1
Skin ulcer * 1  1/725 (0.14%)  1
Surgical and medical procedures   
Incisional drainage * 1  2/725 (0.28%)  2
Vascular disorders   
Accelerated hypertension * 1  1/725 (0.14%)  1
Aortic aneurysm rupture * 1  1/725 (0.14%)  1
Arteriovenous fistula * 1  5/725 (0.69%)  5
Circulatory collapse * 1  1/725 (0.14%)  1
Deep vein thrombosis * 1  3/725 (0.41%)  3
Embolism * 1  1/725 (0.14%)  1
Haematoma * 1  1/725 (0.14%)  1
Hypertension * 1  4/725 (0.55%)  4
Hypertensive crisis * 1  1/725 (0.14%)  1
Hypotension * 1  6/725 (0.83%)  6
Ischaemia * 1  1/725 (0.14%)  1
Orthostatic hypotension * 1  1/725 (0.14%)  1
Temporal arteritis * 1  1/725 (0.14%)  1
*
Indicates events were collected by non-systematic assessment
1
Term from vocabulary, MedDRA 17.1
Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 5%
Micra Pacemaker Implant
Affected / at Risk (%) # Events
Total   0/725 (0.00%)    
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There IS an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Generally, contracts allow investigators to publish study results per the protocol and publication plan. Investigators and Participating Institutions will provide any publication of Study Data generated by PI and/or Participating Institution to Medtronic for review prior to submission to determine if confidential information ("CI") is included and to check for technical correctness. Medtronic may not censor/interfere with the publication beyond the extent necessary to protect CI.
Results Point of Contact
Layout table for Results Point of Contact information
Name/Title: Micra Clinical Team
Organization: Medtronic Cardiac Rhythm and Heart Failure
Phone: 800-328-2518
EMail: MedtronicCRMtrials@medtronic.com
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Layout table for additonal information
Responsible Party: Medtronic Cardiac Rhythm and Heart Failure
ClinicalTrials.gov Identifier: NCT02004873    
Other Study ID Numbers: Micra
First Submitted: December 3, 2013
First Posted: December 9, 2013
Results First Submitted: May 16, 2016
Results First Posted: January 5, 2017
Last Update Posted: January 17, 2018