This 2026 study examines one of the most practical questions in minimally invasive mitral valve repair: which single-dose cardioplegia solution offers better myocardial protection during surgery, Custodiol or Del Nido? The authors focused on patients undergoing minimally invasive mitral valve repair for Carpentier type II pathology, a highly standardized and relatively low-risk population that allowed a cleaner comparison between the two cardioplegia strategies. Their goal was not only to compare safety, but also to study biochemical evidence of myocardial injury after surgery, using postoperative creatine kinase and CK-MB trends as the primary endpoints.
The paper is a retrospective, single-center observational study from a high-volume specialized center. Among 2,490 patients who underwent minimally invasive mitral valve surgery between 2014 and 2025, the investigators excluded many cases that could confound biomarker interpretation, including valve replacements, redo cases, infective endocarditis, urgent surgery, multiple cardioplegia doses, and more complex combined procedures. After these exclusions, 960 patients remained, and 778 were ultimately included in a 1:1 propensity score-matched analysis, creating two balanced groups of 389 patients each. The flowchart on page 3 makes clear that the authors deliberately narrowed the cohort to create a more homogeneous comparison.
That careful narrowing is important, because it improves internal validity even though it limits generalizability. Matching accounted for demographics, clinical risk factors, and operative variables such as cross-clamp time, endoclamping, and repair complexity. As a result, the matched groups were similar in baseline risk, with a mean age of about 59 years and very low operative risk by EuroSCORE II. In effect, the study asked a focused question: in routine, elective, minimally invasive mitral valve repair under single-dose conditions, which solution appears to protect the heart better?
The answer favored Del Nido. The most striking findings came from postoperative enzyme trends. Del Nido was associated with significantly lower CK values across all measured postoperative windows from 0 to 48 hours. CK-MB was also lower with Del Nido in the early periods, especially during the first 24 hours, although by 24 to 48 hours the CK-MB difference was no longer statistically significant. The chart on page 6 visually reinforces this pattern, showing lower smoothed postoperative enzyme curves for Del Nido than for Custodiol. These biomarker results suggest less myocardial injury or at least a more favorable early reperfusion profile with Del Nido cardioplegia.
The clinical course also supported Del Nido in several meaningful perioperative measures. Patients receiving Del Nido had higher perioperative sodium levels, which fits the long-standing concern that the larger volume of Custodiol can contribute to dilutional hyponatremia. Del Nido also showed a much lower rate of ventricular arrhythmias requiring cardioversion after aortic declamping, and when cardioversion was needed, fewer shocks were required. The difference here was large and clinically intuitive: roughly 14% with Del Nido versus more than 40% with Custodiol. Del Nido patients also needed less inotropic support at 6 hours postoperatively. These are not trivial operating-room details. For surgeons and anesthesiology teams, a more electrically stable heart at reperfusion and less early pharmacologic support may translate into a smoother recovery phase, even if major hard outcomes do not change.
At the same time, the study did not show that Del Nido improved major postoperative outcomes such as ICU stay, ventilation time, hospital stay, stroke, perioperative myocardial infarction, acute kidney injury, rethoracotomy for bleeding, or 30-day mortality. In fact, 30-day mortality was 0% in both matched groups. That is reassuring, but it also reflects the highly selected low-risk cohort. The authors are careful not to overstate the results. They conclude that Del Nido appears superior in biomarker dynamics and reperfusion arrhythmia burden, while overall early clinical outcomes remained comparable.
From a practical cardiac surgery perspective, this is the real takeaway: both solutions worked well, but Del Nido may offer better myocardial protection for standard minimally invasive mitral repair cases. The discussion also highlights why this might be so. Del Nido is blood based, uses a smaller total volume, and may provide better electrolyte stability. Custodiol, while useful for prolonged single-dose arrest, carries disadvantages in this context, especially the risk of dilutional hyponatremia and more frequent reperfusion ventricular fibrillation. The paper also notes that Del Nido can be prepared in-house, which may improve cost efficiency.
Still, the limitations matter. This was not a randomized controlled trial. It was retrospective, single center, and subject to temporal bias because the institution transitioned from Custodiol to Del Nido over time. Even though the authors state that no major protocol changes occurred and most surgeons were beyond their learning curves, there is still a possibility that outcomes improved with experience or evolving perioperative care. In addition, the study used surrogate biomarkers rather than long-term clinical outcomes, excluded more complex cases, and does not settle the question of what to do when prolonged ischemic times or redosing are anticipated. The authors explicitly say that future randomized trials are needed, especially for higher-risk patients and longer clamp times.
Overall, this is a strong and clinically useful observational study for surgeons, perfusion teams, and perioperative cardiac care readers. It supports Del Nido as a preferred single-dose cardioplegia strategy for routine low-risk minimally invasive mitral valve repair, while stopping short of claiming superiority in all surgical scenarios. For SEO purposes, the article is especially relevant to readers searching for Del Nido cardioplegia, Custodiol comparison, minimally invasive mitral valve repair outcomes, myocardial protection in cardiac surgery, and propensity score-matched cardiac surgery studies.
