Why Heart Surgery Hospital Rankings Don't Always Tell the Full Story
When you or someone you love is told they need heart surgery, one of the first instincts is to search for the "best" hospital. That usually leads to a ranked list from a magazine or website — and a false sense of certainty about what those rankings mean.
I say this not to dismiss rankings entirely, but to give you a more honest framework. After years of operating in cardiac surgery programs and reviewing cases from hospitals across the country through WhiteGloveMD's second opinion service, I have seen firsthand that the hospital at the top of a popular list is not always the right hospital for every patient or every operation.
The truth is more nuanced. Some hospitals excel at coronary bypass surgery but have limited experience with complex valve reconstruction. Some earn high marks on process metrics but have middling risk-adjusted mortality. And some outstanding programs never appear on consumer-facing lists at all because they did not pay for participation or meet arbitrary volume cutoffs for inclusion.
This article will walk you through the data sources and quality metrics that cardiac surgeons themselves use to evaluate programs — and show you how to apply them to your own decision.
Understanding STS Star Ratings: The Gold Standard for Cardiac Surgery Quality
The Society of Thoracic Surgeons (STS) maintains the most rigorous cardiac surgery outcomes database in the world. It captures detailed clinical data on more than 6 million surgical records and covers roughly 95% of all adult cardiac surgery programs in the United States.
From this data, the STS assigns star ratings — one, two, or three stars — to participating programs for specific procedure categories, including isolated coronary artery bypass grafting (CABG), isolated aortic valve replacement (AVR), and isolated mitral valve surgery. A three-star rating places a program in roughly the top 10-15% nationally for risk-adjusted outcomes in that category.
What Makes STS Star Ratings Different from Magazine Rankings
The critical difference is risk adjustment. STS star rating hospitals are evaluated not on raw mortality numbers, but on how their outcomes compare to what would be expected given the complexity and health status of the patients they treat. A hospital that operates on sicker, older patients with more comorbidities is held to a different statistical benchmark than one operating on lower-risk populations.
This matters enormously. A hospital with a raw mortality rate of 3% may actually be outperforming expectations if their typical patient has an STS predicted risk of mortality of 5%. Conversely, a hospital boasting a 1% mortality rate may be underperforming if their average patient risk is 0.5%.
Where to Find STS Star Ratings
You can look up participating programs at the STS public reporting website. Not every hospital participates in public reporting (participation is voluntary), and star ratings are only assigned when a program has sufficient case volume for statistically meaningful analysis. If a hospital you are considering does not have a publicly available STS star rating, that is worth asking about — but it does not automatically mean the program is low quality.
One important caveat: STS star ratings are procedure-specific. A hospital may earn three stars for CABG but only one star for valve surgery, or vice versa. Always check the rating for your specific operation, not just the hospital's general cardiac surgery reputation.
Beyond Star Ratings: Other Quality Metrics That Matter When Choosing the Best Cardiac Surgery Centers
STS star ratings are the single most reliable publicly available metric, but they do not capture everything. Here are additional data points worth investigating:
Surgical Volume
Decades of research consistently show a relationship between procedural volume and outcomes in cardiac surgery. A landmark study published in the Journal of the American Medical Association found that hospitals performing fewer than 100 CABG cases per year had significantly higher risk-adjusted mortality compared to higher-volume centers. The ACC/AHA guidelines reference volume-outcome relationships as a factor in referral decisions.
Volume is not a guarantee of quality — there are lower-volume programs with excellent outcomes and high-volume programs with mediocre ones. But as a general screening tool, it is useful. For complex operations like mitral valve repair, aortic root replacement, or reoperative surgery, volume becomes even more important because the technical demands are greater and the margin for error is thinner.
Mitral Valve Repair Rate
If you are facing mitral valve surgery for degenerative mitral regurgitation, one of the most telling quality indicators is the program's repair rate. Guidelines from the ACC/AHA recommend repair over replacement for degenerative disease whenever feasible, and reference centers achieve repair rates above 95% for this pathology. If a hospital or surgeon quotes you a repair rate below 80% for degenerative mitral disease, that is a signal to seek another opinion.
Complication Rates Beyond Mortality
Mortality is the most dramatic outcome, but it is not the only one that matters. Ask about rates of:
- Stroke — particularly relevant for valve surgery and aortic procedures
- Deep sternal wound infection — a serious complication that can prolong recovery by months
- Prolonged ventilation (greater than 24 hours) — a marker for how smoothly the postoperative course typically goes
- Renal failure requiring dialysis — especially important for patients with baseline kidney disease
- Reoperation for bleeding — reflects surgical technique and perioperative management
The STS database tracks all of these as part of its composite quality score, and many are publicly reported. A hospital with low mortality but high complication rates may be saving lives but leaving patients with significant morbidity — and that tradeoff should be visible to you.
Teaching Hospital vs. Community Program
Large academic medical centers often attract the most complex cases and have the broadest range of surgical expertise. But community cardiac surgery programs can deliver outstanding outcomes for more common operations like isolated CABG, particularly when led by experienced, high-volume surgeons. The right choice depends on the complexity of your case. For straightforward operations, proximity and the individual surgeon's track record may matter more than the hospital's academic affiliation. For unusual or high-risk operations, the depth of an academic center's team — including specialized anesthesia, perfusion, and intensive care — becomes a significant advantage.
What Popular Heart Surgery Hospital Rankings Actually Measure — and What They Miss
Consumer-facing rankings from outlets like U.S. News & World Report, Healthgrades, and Leapfrog are well-intentioned, but their methodologies have important limitations that most patients never see.
U.S. News & World Report relies partly on reputation surveys sent to physicians, which inherently favor large, well-known institutions. Reputation is not irrelevant, but it can lag behind current performance by years. Their methodology also incorporates process-of-care measures and patient volume, which are imperfect proxies for surgical quality.
Healthgrades uses administrative billing data (Medicare claims) rather than clinical registry data. This means the risk adjustment is less precise than what the STS database provides, because billing codes capture diagnoses but miss critical clinical details like ejection fraction, coronary anatomy, or frailty — all of which dramatically influence surgical risk.
Leapfrog focuses heavily on patient safety measures that apply across all hospital departments, not specifically to cardiac surgery. A hospital may score well on Leapfrog for hand hygiene compliance and medication safety but have unremarkable cardiac surgical outcomes.
None of these rankings are useless, but none should be your sole decision-making tool. Think of them as one data point among many — and always cross-reference with STS-specific data when available.
A Practical Checklist for Evaluating Cardiac Surgery Programs
Based on the metrics above and my experience reviewing hundreds of cardiac surgery cases, here is what I recommend patients and families actually do:
- Look up the STS star rating for your specific procedure at any hospital you are considering. Three stars is excellent. Two stars is average. One star warrants careful scrutiny.
- Ask about annual volume — both for the hospital and for your specific surgeon. For CABG, look for programs doing at least 200 cases per year. For mitral valve repair, ask the surgeon directly how many they perform annually.
- Ask about the surgeon's individual outcomes. Some states (including New York and Pennsylvania) publicly report surgeon-level cardiac surgery mortality data. If this data is available, review it.
- Understand the team, not just the surgeon. Cardiac surgery outcomes depend on the entire perioperative team — the cardiac anesthesiologist, the perfusionist running the heart-lung machine, the ICU nursing staff, and the postoperative care protocols. Ask who will be managing your care after the operation.
- Get a risk estimate for your specific case. Our free cardiac surgery risk calculator can give you a baseline STS predicted risk of mortality, which you can then use to put any hospital's reported outcomes in context.
- Consider getting a second opinion before choosing a hospital. If you have been told you need surgery at one institution, an independent review of your imaging, catheterization data, and clinical records can confirm whether the proposed operation is appropriate — and whether the proposed approach is optimal. This is exactly what we do at WhiteGloveMD.
When Hospital Choice Matters Most — and When It Matters Less
Not every cardiac surgery decision requires traveling across the country to a top-ranked center. For a straightforward, first-time, isolated CABG in a patient with good ventricular function and no significant comorbidities, a well-regarded local program with solid STS data and an experienced surgeon is often the right choice. The benefits of proximity — easier follow-up, family support, reduced stress — are real and should not be dismissed.
But hospital choice becomes critically important in specific situations:
- Complex valve reconstruction, particularly mitral valve repair, where surgeon expertise directly determines whether you receive a repair or a replacement
- Reoperative ("redo") cardiac surgery, where the technical challenges and risks increase substantially
- Combined procedures (e.g., CABG plus valve surgery plus maze procedure for atrial fibrillation), where operative time and complexity escalate
- Aortic root and ascending aortic surgery, where the consequences of technical error can be catastrophic
- Patients with multiple comorbidities or high predicted surgical risk, where experienced teams are better equipped to manage the perioperative course
If your case falls into any of these categories, it is worth casting a wider net in your hospital search — and it is especially worth getting an independent opinion on the surgical plan itself.
The Most Important Variable Is Often Not the Hospital
I want to leave you with something that data consistently supports but that hospital marketing departments will never tell you: for many cardiac operations, the individual surgeon matters at least as much as the institution. A highly skilled, high-volume surgeon operating at a good (but not famous) hospital may deliver better outcomes than an average surgeon at a nationally ranked center. This is particularly true for technically demanding operations like mitral valve repair, where individual surgeon repair rates can range from below 50% to above 99% — within the same hospital.
This is one reason why a second opinion focused on your specific case, your specific imaging, and your specific surgical plan can be more valuable than any hospital ranking list. The question is not just "Is this a good hospital?" but "Is this the right operation, performed by the right surgeon, for my particular anatomy and clinical situation?"
If you are facing a cardiac surgery recommendation and want clarity on whether the proposed plan and setting are right for you, a WhiteGloveMD second opinion can help. Our reviews are conducted by a board-certified cardiac surgeon, incorporate your actual clinical data, and give you a clear, written assessment — including whether the hospital and approach being recommended align with current evidence and best practices. You do not have to navigate this decision alone.