The Evolution of the More ‘Patient-Friendly’ Minimally Invasive Cardiac Surgery
By Todd K. Rosengart, MD, FACS

November 29, 2016



We are experiencing a great revolution in minimizing the invasiveness of heart surgery. Over the past two decades, minimally invasive cardiac surgery (MICS) has become increasingly popular as the benefits of this approach have been proven and the techniques to perform MICS safely and successfully have evolved.

MICS comes in several different forms, including “off-pump” procedures that avoid the use of the heart-lung machine. However, differences in outcomes between on-pump and off-pump procedures are generally limited to coronary bypass surgery and have proven to be difficult to demonstrate, except in some high-risk populations.

MICS is sometimes defined as heart surgery that avoids the use of a full sternotomy—dividing the breastbone or “cracking the chest.” Approaches used in MICS include:

  • Partial or “mini-sternotomy” in which the surgeon cuts through the upper third of the breast bone
  • “Mini-thoracotomy,” in which the surgeon accesses the heart through small incisions between the ribs

These MICS operations are typically used for heart valve replacement and repair procedures and require use of the heart-lung machine. In contrast with off-pump and full-sternotomy procedures, they are distinguished by the improved outcomes associated with smaller, less-invasive incisions.

Research shows that the mini-sternotomy and mini-thoracotomy approaches not only result in short- and long-term safety and survival outcomes at least as good as the traditional sternotomy approach, but also yield significant benefits that include reduction in:

  • Blood loss
  • Time spent in the intensive care unit
  • Length of hospital stay
  • Hospital costs
  • Overall recovery time


Comparing outcomes data between mini-sternotomy and mini-thoracotomy approaches, together with other benefits including the smaller and less visible incision scars offered by the mini-thoracotomy, it is my opinion that the mini-thoracotomy approach yields superior benefits overall.

Despite the documented advantages of these MICS procedures, only about 20% of US surgeons use mini-sternotomy or mini-thoracotomy approaches in performing valve surgery. This slow adoption rate is likely related to the more challenging technical nature of these procedures, which often requires special training beyond that obtained in residency programs. However, improvements in surgical instrumentation and techniques, heart perfusion strategies, surgical imaging technologies, and even the newest “sutureless” heart valves have enhanced the safety and applicability of mini-sternotomy and mini-thoracotomy procedures, and will hopefully expand their use.

Robotic-assisted cardiac surgery is another type of minimally invasive heart surgery. In comparison to traditional MICS, robotic-assisted cardiac surgery requires the use of high-precision robotic instruments that allow the surgeon to perform procedures through incisions even smaller than those in a mini-sternotomy or mini-thoracotomy. Limited data regarding the benefits of robotic over other “mini” cardiac surgery approaches is available, but the difficult learning curve, longer operative time, and greater expense associated with this technically demanding procedure has restricted its availability to only the highest volume, most experienced centers. 

More widely available than robotic-assisted cardiac surgery is transcatheter aortic valve replacement (TAVR). The procedure was pioneered 10 years ago. During TAVR, diseased heart (aortic) valves are replaced with artificial tissue valves delivered without any surgical incisions at all, but instead through a catheter. Even while the long-term outcomes of TAVR are unknown and surgery remains the gold standard for heart valve surgery when the surgical risk is favorable, I believe it is essential that we offer MICS to our patients to minimize the invasiveness of heart valve surgery.

Demands for MICS procedures will continue to increase as patients, insurers, and providers learn more about of its clinical benefits and cost effectiveness. Patients interested in MICS should discuss the benefits and risks of minimally invasive and traditional approaches with a heart surgeon experienced in minimally invasive surgery.

Read more about minimally invasive surgery in Adult Heart Disease.

Read more blog articles.

The opinions expressed in this article are those of the author and do not necessarily reflect the views of The Society of Thoracic Surgeons.

The Society of Thoracic Surgeons

The STS mission is to advance cardiothoracic surgeons’ delivery of the highest quality patient care through collaboration, education, research, and advocacy.