Public Reporting Glossary of Terms

The Society of Thoracic Surgeons, or STS, is a not-for-profit professional association representing cardiothoracic surgeons, researchers, and allied health care professionals dedicated to ensuring the best possible outcomes for surgeries of the heart, lungs, and esophagus, as well as other surgical procedures within the chest. 

The STS National Database is a clinical outcomes registry comprised of four components, each focusing on a different area of cardiothoracic surgery: Adult Cardiac Surgery, Congenital Heart Surgery, General Thoracic Surgery, and mechanical circulatory support (Intermacs).  

Public reporting is not available to Intermacs participants at this time.  

A coronary artery blockage is a narrowing of the arteries around the heart preventing oxygen-rich blood from reaching the heart muscle.

Coronary artery bypass graft surgery, or CABG (often pronounced “cabbage”), is the most commonly performed heart operation in the US. CABG is a surgical procedure that restores blood flow to the heart when one or more coronary arteries are blocked, or severely narrowed, due to coronary artery disease (CAD). The procedure is also known as coronary revascularization or heart bypass surgery.

In this procedure, the surgeon takes a patient’s healthy artery or vein, usually from the leg, arm, chest, or abdomen, and uses it to “bypass,” or go around, the diseased or blocked portion of the coronary artery. This creates a new path for blood flow to the heart.  

A breakdown of the STS CABG composite rating is online here.

Aortic valve replacement, or AVR, is a surgical procedure to replace a damaged or diseased aortic valve with a new artificial valve, either mechanical or biological, to restore normal blood flow from the heart to the body.

A breakdown of the STS AVR composite rating is online here.

Combined AVR and CABG, or AVR+CABG, is a surgical aortic valve replacement (AVR) combined with coronary artery bypass graft (CABG) surgery during the same trip to the operating room.

A breakdown of the STS AVR+CABG composite rating is online here.

Mitral valve replacement, or MVR, is a surgical procedure to remove a damaged mitral valve, which controls blood flow between the heart’s left atrium and left ventricle, and replace it with a new artificial valve, either mechanical or biological. This restores normal blood flow through the heart.

Mitral valve repair, or MVr, is a surgical procedure to fix a malfunctioning mitral valve, which controls blood flow between the heart’s left atrium and left ventricle, and improve heart function and reduce symptoms. A mitral valve repair procedure does not involve removing the patient’s native valve. During this procedure, the surgeon may:

• Reshape or reinforce valve leaflets to ensure proper closure
• Remove excess tissue or repair damage to the valve structure
• Use devices, such as bands or rings, to help improve valve function

In the STS National Database, MVRR combines all of a participant’s MVR and MVr procedures together for data analytic purposes only as MVRR. 

A breakdown of the STS MVRR composite rating is online here.

Combined MVRR and CABG, or MVRR+CABG, is a surgical mitral valve replacement OR a surgical mitral valve repair combined with coronary artery bypass graft surgery during the same trip to the operating room.

A breakdown of the STS MVRR+CABG composite rating is online here.

Operative mortality, or patient death, is defined as a death that occurs:

• During the hospital stay in which the procedure was performed, no matter how long the patient remains in the hospital after the operation;
• At another hospital because the patient is transferred but is never discharged; OR
• Within 30 days of the operation, if the patient is discharged home.

STAT Mortality Categories 1-5  

Congenital heart operations are grouped by the complexity of the procedure in what is known as STAT Categories. STAT Category 1 includes the least complex operations, which are associated with the lowest risk of mortality. STAT Category 5 includes the most complex operations, which are associated with the highest risk of mortality. Examples of surgeries include:

• STAT Category 1: Patch repair of Atrial Septal Defect (ASD) or Ventricular Septal Defect (VSD) pulmonic valve replacement
• STAT Category 2: Complete AV Canal (AVC) repair, Arterial Switch Operation (ASO)
• STAT Category 3: ASO + VSD repair, heart transplant, aortic arch augmentation
• STAT Category 4: Truncus arteriosus repair, TAPVC repair
• STAT Category 5: Norwood procedure, truncus arteriosus repair + Interrupted arch repair

A breakdown of STS CHSD operative and adjusted operative mortality is online here.

Resection for primary lung cancer is a surgical procedure to remove part, or all, of a patient’s lung as treatment for lung cancer. Resection surgeries are performed using minimally invasive or open techniques and surgery types include wedge resection, segmentectomy, lobectomy, and pneumonectomy.

A breakdown of the STS resection for primary lung cancer composite measure is online here.

Esophagectomy for esophageal cancer is a surgical procedure to remove part, or all, of a patient’s esophagus as treatment for esophageal cancer. Typically, this procedure includes reconstruction of the esophagus using part of the stomach.  

A breakdown of the STS esophagectomy for esophageal cancer composite measure is online here.

A participant’s case mix refers to the types of patients being treated, including their age, health conditions, how serious their heart, lung, or esophageal problems are, and other factors. By accounting for and controlling patient risk factors present before surgery, risk adjustment “levels the playing field” as best as possible. Specifically, some hospitals care for more ill patients, and those patients are at greater risk of dying due to their underlying conditions, not necessarily because of the care they receive.

Risk adjustment accounts for these risk factors and allows STS database participants to compare their performance to other groups, such as the overall STS cohort, other participants, or by region or state. Unadjusted event rates are not used for these comparisons because they may be affected by variation in patient case mix and disease severity across participants.  

Using risk adjustment provides a more accurate reflection of a participant’s performance relative to a reference cohort with similar patient characteristics. Direct comparisons between the risk-adjusted mortality rates of two individual participants are generally inadvisable unless their patient populations are relatively similar. 

The operative mortality rate is the percentage of patients undergoing heart surgery who died during the hospitalization in which the surgery was performed and those who died within 30 days of the surgery if they were discharged from the hospital.

The morbidity rate, also known as complication rate, is the percentage of patients undergoing heart surgery, who experienced at least one of the five most serious complications of cardiac surgery: reoperation, stroke, kidney failure, infection of the chest wound, or prolonged need to be supported by a breathing machine or ventilator. 

Perioperative refers to all three stages of surgery: preoperative (before surgery), intraoperative (during surgery), and postoperative (after surgery). 

A quality performance measure is a numeric calculation of health care quality that can be used to monitor, assess, and improve the quality of patient care.