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Second in a Series: Low-Volume Cardiac Surgery Programs – Looking “Behind” the Numbers

John Meyer, FACHE


In our recent post, Low-Volume Cardiac Surgery Program “Excellence, we initiated a multi-part series discussion on the theme of cardiac program excellence.  In this article, we address the importance of understanding one’s cardiac program volumes and the difference in key types of procedures that comprise your cardiac surgery program’s procedure volume.

If information is vital to making informed decisions, then appropriate analysis of low-volume cardiac surgery programs must include informed analytics.  CFA recently received a call from a hospital administrator concerned that his cardiac surgery program was faltering and steadily declining in volume.  When we asked how many cardiac surgeries they performed, he replied, “Well, we budgeted for 48 this fiscal year.”  This was down from well over one hundred surgeries during the previous years.  By most any standard, 48 annual cardiac surgical procedures constitutes a low volume program.  Our next question to him was important.  We asked “48 what exactly?”  When we probed, he wasn’t sure what the answer was – 48 total cardiac surgeries, CABG procedures only, CABG/Valve cases, other thoracic, other major vascular, all cases performed by his hospital’s cardiothoracic (CT) surgeon, or what exactly[i]

Accurate Numbers Yield Informative Analyses

To analyze the situation and develop strategic options going-forward, hospitals will need to do a thorough analysis of their own internal volumes, local and regional market volumes and the trends within that market; generally reduced to market size and share, with trends over time – in other words, the “numbers.”  While this seems obvious, anything more than a cursory analysis requires “looking behind the numbers” to appropriately segment available data in a meaningful way.  Frequently, CFA is faced with a dearth of usable market-based data, or data that is inappropriately segmented, lumped or split, restricting the ability of the user to produce meaningful results[ii].  This is where our experience kicks in; producing meaningful analytics, often from challenging source materials, and using this data to developing consequential “root-cause” analyses and supportable volume projections.  In this blog, we will look behind the numbers for cardiac surgery.

Comparative databases, where available, are typically designed and developed by generalists with limited clinical cardiovascular knowledge.  CFA has actually served as a content expert in some database development, but still the nomenclature and documentation lags behind real-world usage and technological change.  A good case in point is cardiac surgery[iii].  To understand the cardiac surgery market and to reveal the issues that may exist behind the numbers, one must look carefully, filling in gaps in knowledge with experience and relying upon that experience to both identify the underlying issues and understand the implications that logically follow.

Let’s look at our cardiac surgery example.  At the MS-DRG level, “Cardiac Surgery” could consist of any of the following FY 2016 codes in logical groupings (note that we have excluded Major Thoracic and Major Vascular DRGs, which occasionally get lumped into this category by some facilities):

 MS-DRGs (Groupings)  Summary Description
 DRGs 216 – 221

Cardiac Valve & Other Major Cardiothoracic Procedures; with and without Cardiac Cath; with and without CC/MCC

 DRGs 228 – 230

Other Cardiothoracic Procedures; with and without CC/MCC

 DRGs 231 – 236

Coronary Bypass; with and without Cardiac Cath; with and without PTCA; and with and without CC.MCC

 DRGs 266 – 267

Endovascular Cardiac Valve Replacement with and without MCC

 DRGs 270 – 272

Other Major Cardiovascular Procedures; with and without CC/MCC

As one can see, there is more to “cardiac surgery” than CABG and valves!  To further this analysis, let’s look at a typical distribution of the three major categories of cardiac surgery cases (note that Endovascular Cardiac Valve Replacement is lumped with Valve Surgery in this analysis, and should be considered separately – see below), this time using the STS database for 2015 as an example.  Of course, local/regional distribution will vary, depending on factors such as demographics (the older the population, the higher the prevalence of valve surgery), surgical capability (some CT surgeons do not do enough valve surgery to retain competence; some hospitals virtually specialize in cardiac valve surgery work), mix of valve cases (aortic, mitral, repair versus replace), and so on.

  Society for Thoracic Surgery,
Adult Cardiac Surgery Database,
STS Period Ending 3/31/2015,
Executive Summary – % Volume by Cases



Valve Surgery


Other Major CV Surgery


Total Cardiac Surgery


Cardiac Surgery Is More than CABG

Admittedly, CABG surgery volumes serve as the bell weather for full-service cardiac programs.  While acknowledging that the majority of cardiac surgery attention and public reporting focuses on high volume, high profile CABG, and that many states that report CABG volumes do not even report valve surgery volumes (e.g., California, New York, Pennsylvania), any thorough analysis of surgical volume needs to consider the totality of cardiac surgical procedures both in the market and as the hospital’s share, and the relative ability of staff cardiothoracic surgeons to perform the full complement of procedures that may exist within a specific market area or referral base.  Note that the volumes of surgical procedures are inextricably linked between the hospital program and the cardiothoracic surgical staff.  If, for example, CABG surgery volumes have held steady, but valve surgery volumes have declined, there may be an issue relating to one or more of the following factors:

  • The increase in endovascular valve replacement procedures. Transcatheter aortic valve replacement (TAVR) is replacing open surgical procedures for medium- to high-risk individuals, but can best be done by qualified surgeons at high volume institutions that meet rigorous Medicare volume and quality requirements.
  • The overall clinical interest level, capability and/or quality outcomes of individual surgeons. Note that further differentiation can be made on specific types of valve procedures – aortic repair or replacement, mitral valve repair or replacement and/or combination valve/CABG procedures – and the capability and specialization of the surgical staff to deal with these.
  • The overall reputation and brand-awareness of the hospital’s program in its competitive marketplace.

Implications for Low-Volume Cardiac Surgery Programs

Under typical circumstances in many moderate sized and higher volume programs, CABG and cardiac valve surgery cases will account for approximately 80% of a hospital’s mix of cardiac surgical cases.  One must recognize that there are another 20% of surgeries that need to be considered.  While the relative “health” of a surgical program is often gauged primarily by CABG volumes, and sometimes CABG and valve surgery volumes combined, there are other cardiac-related surgical procedures performed by CT surgeons that go to make up the overall clinical and financial health of a surgical program[iv].  It is important to look “behind” the numbers, not just to understand the specific volumes by surgical type, but to ascertain the relative clinical strengths and weaknesses of both the hospital, opportunities for growth in non-CABG cardiac surgery and the surgeon(s) performing these procedures.  “Unbundling” cardiac surgery from overly broad clinical categories is required to best understand volume by category.  This can be challenging, as many databases inappropriately lump and split volumes, reducing their meaning and hiding the important implications revealed “behind the numbers.”

If you are interested in learning more about strategies to deal with low-volume surgical programs and/or programmatic assessment for cardiovascular services, please contact CFA at (949) 443-4005 or by e-mail at Also, please download our free low volume whitepaper offered below.

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[i] Of note is the fact that this particular hospital reports “Open-Heart Surgeries” to its State health department with no other breakdown except between total “adult” and “pediatric” admissions.

[ii] When requesting data, CFA issues a detailed request that specifies the need for data by individual MS-DRG within MDC-5 and related cardiovascular procedures in other MDCs, further grouped by twelve (12) logical subcategories (such as Heart Assist System Implant, Carotid Artery Procedures, and so on).

[iii] Another example is the not infrequent lumping of “Cardiac Cath and PCI” into one category by some databases, with similar challenges in separating and thus understanding these two disparate procedures. 

[iv] CFA recognizes that there are many ways to evaluate a surgical program beyond simple volumes (e.g. costs, ALOS, readmission rate, mortality and other clinical quality rates).  This blog addressed the issues surrounding understanding volumes only.

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