Minimally invasive thoracoscopically-guided right minithoracotomy versus conventional sternotomy for mitral valve repair

ISRCTN	ISRCTN13930454
DOI	https://doi.org/10.1186/ISRCTN13930454
Central Portfolio Management System (CPMS)	31443
Sponsor	South Tees Hospitals NHS Foundation Trust
Funder	Health Technology Assessment Programme

Submission date: 22/08/2016
Registration date: 12/09/2016
Last edited: 18/11/2025

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Circulatory System

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
Heart surgery to repair one of the valves in the heart (the mitral valve) is commonly performed in the NHS. Patients needing this operation sometimes suffer symptoms of shortness of breath (especially when exercising), tiredness, and swollen ankles, caused by the valve becoming leaky (mitral regurgitation). Some patients suffer very few symptoms. These patients are quite often of working age so time away from their place of work can be difficult for a number of reasons. Steps need to be taken to make sure that the operations offered within the NHS are best for patients. To repair the valve, the operation usually involves cutting the breastbone completely (from the collar bone to the bottom of the breastbone); this is called a sternotomy. An operation has been developed which means that the valve can be repaired using a much smaller cut on the side of the chest; this operation is called a mini-thoracotomy. It is not known which operation is better for patients and for the NHS because there is no good research to show what effects two different types of surgery to access the heart and repair the valve have on patients. This study will compare the two operations in four hundred adult patients to see how well they recover and return to normal activities.

Who can take part?
Adult patients with degenerative mitral valve disease requiring isolated mitral valve repair surgery.

What does the study involve?
Participants are randomly allocated to one of two groups. Those in group 1 are given a mini-thoracotomy. Those in group 2 are given a sternotomy. Patients are asked questions about their physical activities and quality of life before and at various times after the operation. Other important factors are also be checked to see how well patients recover, including how well their valve works up to twelve weeks and twelve months after surgery using a heart scan (called an echocardiogram). Patients are asked to wear a device that measures their activity for one week on seven occasions; the device looks like a wrist-watch and can be worn all day and all night. Any complications following a patient’s operation is recorded from their medical records. Costs of care for each operation is also calculated by looking at medical records to see how often patients are seen in hospital after their operation. Patients who take part attend hospital a few times in the first year, after this their progress is monitored by reviewing their medical notes. Patients are asked to confirm that they are happy that the researchers keep looking at their medical records, even after the trial is finished.

What are the possible benefits and risks to participants?
This research does not carry any additional risk compared to surgery performed as part of usual care.

Where is the study run from?
The study will include patients from NHS hospitals in England, including the South Tees Hospitals NHS Foundation Trust (lead centre and sponsor), King’s College Hospital NHS Foundation Trust, Basildon and Thurrock University Hospitals NHS Foundation Trust, Blackpool Teaching Hospitals NHS Foundation Trust. The study will run in collaboration with Durham Clinical Trials Unit, Durham University, UK.

When is the study starting and how long is it expected to run for?
January 2016 to May 2023

Who is funding the study?
National Institute of Health Research – Health Technology Assessment Programme (UK)

Who is the main contact?
Mr Enoch Akowuah
enoch.akowuah@nhs.net

Contact information

Dr Sonya Collins
Scientific

Newcastle Clinical Trials Unit
1-4 Claremont Terrace
Newcastle University
Newcastle upon Tyne
NE2 4AE
United Kingdom

Phone	+44 (0)191 2087252
Email	sonya.collins@newcastle.ac.uk

Mr Enoch Akowuah
Scientific

Consultant Cardiothoracic Surgeon
The James Cook University Hospital
South Tees Hospitals NHS Foundation Trust
Marton Road
Middlesbrough
TS4 3BW
United Kingdom

Phone	+44 (0) 1642 850 850 ext 53922
Email	enoch.akowuah@nhs.net

Study information

Primary study design	Interventional
Study design	Randomized; Interventional; Design type: Treatment, Surgery
Secondary study design	Randomised controlled trial
Scientific title	Minimally invasive thoracoscopically-guided right minithoracotomy versus conventional sternotomy for mitral valve repair: a multicentre randomised controlled trial (UK Mini Mitral).
Study objectives	This randomised controlled trial will investigate whether the minimally invasive thoracoscopically-guided right minithoracotomy approach to mitral valve repair allows for an improved return of physical functioning and a return to usual activities when compared to conventional sternotomy at 12 weeks. Additionally, the study will compare the cost-effectiveness of the two surgical approaches at 52 weeks.
Ethics approval(s)	Gwasanaeth Moeseg Ymchwil Research Ethics Service, 28/06/2016, ref: 16/WA/0156
Health condition(s) or problem(s) studied	Degenerative mitral valve disease
Intervention	Patients are randomised to one of two groups. Those in group 1 receive mitral valve repair surgery by thoracosopically-guided right minithoracotomy (intervention group). Those in group 2 receive mitral valve repair surgery via a median sternotomy (control group). 1. Intervention group: Minimally invasive surgery is by thoracoscopically-guided right minithoracotomy. The patient is intubated with a single or double lumen endotracheal tube. Cardiopulmonary bypass is established by aortic or femoral artery cannulation and venous return is achieved from the venae cavae using a single bicaval cannula placed from the femoral vein or with an additional cannula in the superior venae cava. Transoesophageal echocardiography (TOE) confirms the optimum location of the venous and arterial cannulas. A 4-7 cm right antero-lateral mini-thoracotomy, is then used to enter the thorax through the third or fourth intercostal space. A soft tissue retractor with or without a small thoracic retractor is utilized to spread the ribs with minimal rib-spreading. The pericardium is opened 3-4 cm anterior and parallel to the phrenic nerve from the distal ascending aorta to the diaphragm. A video camera is inserted through a 5-10 mm port. Endoballoon occlusion or a transthoracic clamp achieves aortic occlusion. Cardiac arrest is achieved with single or repeated doses of cardioplegia. The mitral valve is approached through a paraseptal incision and a left atrial retractor is used to expose the mitral valve. Following the mitral valve procedure, the left atrium is closed, the heart de-aired and aortic occlusion removed. Cardiopulmonary bypass is then discontinued and the thoracotomy incision closed once haemostasis has been achieved. 2. Control group: Conventional mitral valve surgery will be performed via a median sternotomy, in which the sternum is divided completely (from the collarbone to the bottom of the breastbone). The operation includes cardiopulmonary bypass established by siting cannulas in the right atrium and inferior venae cava and ascending aorta. The heart is stopped with cardioplegia and the mitral valve is approached via the left atrium. The valve is repaired and assessed intra-operatively by water testing. If the repair is deemed satisfactory, the atrium is closed, de-airing manoeuvres are performed, and the aortic cross clamp is removed to allow reperfusion of the heart. Cardiopulmonary bypass is then discontinued and once haemostasis is performed the sternum is closed. Patients will be randomised in a 1:1 ratio, using a minimisation scheme that will account for baseline SF-36v2 physical functioning score and the presence or absence of Atrial Fibrillation. Patients will be followed-up for a period of 52 weeks on each treatment arm.
Intervention type	Other
Primary outcome measure(s)	The change in the SF-36v2 physical functioning scale at 12 weeks post-surgery. The SF-36v2 is a generic multi-dimensional and validated instrument consisting of eight multi-item components representing physical function, social function, role limitation attributable to physical problems, role limitation attributable to emotional problems, mental health, energy, pain, general health perception.
Key secondary outcome measure(s)	1. Level and variability in physical activity: measured using one week of accelerometer measurements at 7 time points (baseline, and 6, 12, 18, 24, 38 and 52 weeks following index surgery) 2. Quality of sleep: measured using one week of accelerometer measurements at 7 time points (baseline, and 6, 12, 18, 24, 38 and 52 weeks following index surgery) 3. Surgical outcomes (including duration of operation, cardiopulmonary bypass times, anaesthetic regime, protocol adherence), measured using data collected at the time of index surgery 4. Costs, including intervention-specific estimates, of the two operations, measured using data collected at the time of index surgery 5. Mitral valve related events determined using HES, NICOR, and medical record data, measured using adverse event data collected for 52 weeks within the trial, and through requests to HSCIC and NICOR for event data 6. Left ventricular volumes and function, mitral regurgitation, right heart function, and pulmonary artery pressure, measured by Echocardiograms at baseline, post-operatively and at 52 weeks following index surgery 7. Survival Measured throughout the trial and using ONS data 8. Physical functioning using SF-36v2, measured using the SF-36v2 questionnaire administered at 7 time points (baseline, and 6, 12, 18, 24, 38 and 52 weeks following index surgery) 9. Quality of life using SF-36v2 and EQ-5D-5L, measured using the SF-36v2 and EQ-5D-5L questionnaires administered at 7 time points (baseline, and 6, 12, 18, 24, 38 and 52 weeks following index surgery) 10. Adverse Events and Serious Adverse Events, measured throughout the trial using a combination of patient reported events and data provided by HSCIC and NICOR 11. Health care utilisation, measured using patient reported health care utilisation questionnaires at 6, 12, 18, 24, 38 and 52 weeks following index surgery 12. Wound pain, measured using an 11 point VAS scale at 3 days, 6 weeks and 12 weeks following index surgery 13. NYHA class, measured using the standard NYHA classifications at baseline, 6 and 12 weeks following index surgery 14. Length of hospital stay, measured from routinely collected hospital data following index surgery 15. Medication usage, measured using patient reported medication usage at baseline, and at 6, 12 and 52 weeks following index surgery. 16. Re-operation, measured using routinely collected hospital data following index surgery 17. Conversion (minimally-invasive arm only), measured using routinely collected hospital data following index surgery 18. Red blood cell and blood product transfusions, measured using routinely collected hospital data following index surgery 19. Time on ICU, HDU and ward, measured using routinely collected hospital data following index surgery 20. Discharge destination, measured using routinely collected hospital data following index surgery 21. Duration of ventilation, measured using routinely collected hospital data following index surgery 22. Blood loss following surgery, measured using routinely collected hospital data following index surgery
Completion date	31/05/2023

Eligibility

Participant type(s)	Patient
Age group	Mixed
Lower age limit	18 Years
Upper age limit	100 Years
Sex	All
Target sample size at registration	316
Total final enrolment	330
Key inclusion criteria	1. Adult (≥18 years old at consent) patients with degenerative mitral valve disease, requiring isolated MVr (patients requiring concomitant surgery for Atrial Fibrillation and/or Patent Foramen Ovale (PFO) closure will be included) 2. Written informed consent 3. Fit for cardiac surgery and cardiopulmonary bypass
Key exclusion criteria	1. Concomitant cardiac surgery other than AF ablation and PFO closure 2. Requiring mitral valve replacement 3. Acute infective endocarditis 4. Emergency or salvage surgery 5. Only conventional median sternotomy or only minimally invasive surgery indicated 6. Pregnant* 7. Currently participating in another interventional clinical trial 8. Four weeks or more as an inpatient prior to randomisation 9. Previous cardiac surgery *Female patients between the ages of 18 and 50 will receive a pregnancy test at baseline
Date of first enrolment	22/08/2016
Date of final enrolment	31/05/2021

Locations

Countries of recruitment

United Kingdom
England

Study participating centres

The James Cook University Hospital (Lead Centre)

Marton Road
Middlesbrough
TS4 3BW
England

King's College Hospital

Denmark Hill
Denmark Hill
SE5 9RS
England

Blackpool Victoria Hospital

Whinney Heys Road
Blackpool
FY3 8NR
England

Basildon University Hospital

Nethermayne
Basildon
SS16 5NL
England

NHS Lothian

Waverley Gate
2-4 Waterloo Place
Edinburgh
EH1 3EG
Scotland

Hammersmith Hospitals NHS Trust

Hammersmith Hospital
Du Cane Road
London
W12 0HS
England

Harefield Hospital NHS Trust

-
Harefield
UB9 6JH
England

University Hospitals Bristol and Weston NHS Foundation Trust

Trust Headquarters
Marlborough Street
Bristol
BS1 3NU
England

University Hospitals Plymouth NHS Trust

Derriford Hospital
Derriford Road
Derriford
Plymouth
PL6 8DH
England

Liverpool Heart and Chest Hospital NHS Foundation Trust

Thomas Drive
Liverpool
L14 3PE
England

Results and Publications

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not expected to be made available
IPD sharing plan

Study outputs

Output type	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	13/06/2023	15/06/2023	Yes	No
Results article	18/11/2025	18/11/2025	Yes	No
Protocol article	14/04/2021	16/04/2021	Yes	No
HRA research summary		28/06/2023	No	No
Statistical Analysis Plan		04/10/2024	No	No

Editorial Notes

18/11/2025: Publication reference added.
04/10/2024: Statistical analysis plan added.
15/06/2023: Publication reference added.
27/10/2022: The following changes were made to the trial record:
1. The recruitment end date was changed from 31/10/2020 to 31/05/2021.
2. The trial participating centres NHS Lothian, Hammersmith Hospitals NHS Trust, Harefield Hospital NHS Trust, University Hospitals Bristol and Weston NHS Foundation Trust, University Hospitals Plymouth NHS Trust, Liverpool Heart and Chest Hospital NHS Foundation Trust were added.
23/12/2021: The following changes were made to the trial record:
1. The overall end date was changed from 31/05/2021 to 31/05/2023.
2. The intention to publish date was changed from 31/12/2021 to 31/12/2023.
3. The plain English summary was updated to reflect these changes.
4. The total final enrolment was added.
16/04/2021: Publication reference added.
20/08/2020: The primary contact has been changed.
15/06/2020: The scientific contact details have been made publicly visible.
24/09/2019: The following changes have been made:
1. The recruitment end date has been changed from 31/01/2020 to 31/10/2020.
2. The target enrolment numberhas been changed from 400 to 316, with 158 in each arm.
29/04/2019: Contact details updated.
28/03/2019: The condition has been changed from "Specialty: Cardiovascular disease, Primary sub-specialty: Cardiac surgery; UKCRC code/ Disease: Cardiovascular/ Other forms of heart disease" to "Degenerative mitral valve disease" following a request from the NIHR.
13/09/2016: Internal review.