Valvular Surgery: Minimally Invasive vs Conventional Sternotomy

Comparison of Outcomes for Minimally Invasive and Conventional Cardiac Valvular Surgery: A Prospective Cohort Study

The conventional approach to heart valve operations is through a sternotomy. This involves a vertical incision in the sternum (breastbone) to gain access to the heart and its related structures. Post-operative recovery after sternotomy can take anywhere from 6 weeks to 3 months due to the time required for the sternum to fully heal.

Minimally invasive valve surgery is a less invasive alternative to conventional open-heart surgery. At the Foothills Medical Centre, surgeons perform minimally invasive valve surgery through a technique called right mini-thoracotomy. This involves a small incision on the right upper chest and leaves the sternum fully intact. It is unclear whether minimally invasive valve surgery provides better clinical outcomes and quality of life compared to conventional open heart surgery.

The purpose of this research study is to compare the clinical outcomes of minimally invasive valve surgery via right mini-thoracotomy to conventional surgery via open-heart surgery. The results of this study will inform surgeons of the benefits and disadvantages of minimally invasive surgery compared to the current standards. This will help in developing better treatment strategies for patients requiring valve therapy.

BACKGROUND & RATIONALE: The conventional approach to heart valve operations is open-heart surgery. This involves a vertical incision along the sternum (breastbone) and splitting it in half to gain access to the heart and its related structures. Open-heart surgery provides maximal exposure of the heart to the surgeon and results in good clinical outcome. However, post-operative recovery after open-heart surgery can take anywhere from 6 weeks to 3 months due to the time required for the sternum to fully heal. During this time patients can experience considerable pain and reduced mobility which have a significant negative impact on quality of life and productivity. Patients are also prone to major sternal complications such as wound opening and sternal infection, all of which may compromise respiratory function and overall recovery.

Minimally invasive valve surgery is a less invasive alternative to open-heart surgery. At the Foothills Medical Centre, surgeons perform minimally invasive valve surgery through a technique called right mini-thoracotomy. This involves a small incision on the right upper chest and leaves the sternum fully intact. This approach has been increasingly favoured and adopted by patients and physicians due to the benefits of avoiding sternal complications associated with open-heart surgery as well as cosmetic benefits. Despite these benefits, it is still unclear whether minimally invasive valve surgery provides better clinical outcomes and quality of life compared to conventional open-heart surgery.

RESEARCH QUESTION & OBJECTIVES: The aim of this observational research study is to assess the post-operative functional recovery and clinical outcomes of minimally invasive valve surgery via right mini-thoracotomy and conventional surgery via full median sternotomy. The objectives of this study are:

1. To assess post-operative functional recovery in minimally invasive and conventional valve surgery patients by assessing recovery of respiratory function, pain, physical function, and quality of life back to baseline.
2. To assess post-operative complications in minimally invasive and conventional valve surgery patients by assessing the incidence of early mortality, stroke, post-operative atrial fibrillation, permanent pacemaker implantation, paravalvular leak, pulmonary complication, wound infection, acute kidney injury, and reoperation.
3. To assess post-operative valve function in minimally invasive and conventional valve surgery patients by assessing valve gradients and degree of leakage.
4. To assess perioperative support for minimally invasive and conventional valve surgery patients by assessing ventilation time, cardiopulmonary bypass time, cross-clamp time, amount of blood transfusion, analgesic requirements, and length of ICU and hospital stay.

METHODS: The proposed clinical study is a single-center, prospective cohort study. All participants will undergo data collection procedures over a 12-month follow-up period. Specifically, data regarding demographics, medical history, and medications will be collected, and spirometry testing with a hand-held spirometer will be performed at baseline. Patients will be evaluated in hospital on post-op Day 3 and at discharge for pain, analgesic/antibiotic use, wound healing, any clinical events, quality of life (EQ-5D), and spirometry. Subsequently, patients will return to hospital for follow-up visits post operatively for physical examination, interview, additional quality of life questionnaires (EQ-5D, KCCQ-23, Health Assessment Questionnaire), and spirometry testing at 2 weeks, 6 weeks, and 3 months after surgery, with a final phone interview at 12 months.

Inclusion Criteria:

• Aged ≥ 18 years of age
• Undergoing non-emergent isolated aortic valve or mitral valve surgery
• Full median sternotomy approach or minimally invasive approach via right anterior/anterolateral mini-thoracotomy
• English speaking
• Geographically accessible; able and willing to attend follow-up visits
• Written informed consent

Exclusion Criteria:

• Recent CPR
• Previous cardiac surgery
• Emergency surgery (operative intervention within 24 hours of assessment)
• Previous permanent pacemaker implantation
• Poor respiratory function - two or more measurements of FVC, FEV1, or PEF <80% of predicted value based on age, gender, and height at baseline
• History of a bleeding disorder
• Excessively poor baseline health-related quality of life or physical functioning that would preclude a reasonable expected post-operative recovery to baseline
• Active significant systemic infection, (e.g. endocarditis, sepsis) a history of recurrent systemic infections; or have taken an antibiotic within 2 weeks prior to surgery
• Cognitive impairment (e.g., confusion, dementia, Alzheimer's disease, current substance abuse) that would preclude completion of survey questions or following instructions to complete pulmonary function testing
• History of malignancy within the past year (except for squamous or basal cell carcinoma of the skin that has been treated, with no evidence of recurrence)
• Recent history of significant drug or alcohol abuse
• Participation in another study that would affect the ability to obtain adequate follow-up