Acute type A aortic dissection remains one of the most complex emergencies in cardiovascular surgery, and coronary ostial compromise represents a particularly challenging anatomic scenario, frequently associated with increased perioperative mortality. When the intimal disruption extends into the coronary origins, the likelihood of myocardial malperfusion rises substantially. Coronary ostial reconstruction (COR) continues to be the most frequently adopted strategy, yet it does not always guarantee durable restoration of antegrade coronary flow—especially in anatomically severe cases. This leads to a recurrent question in the operating room: should one attempt to preserve native anatomy through ostial repair alone, or is it preferable to add coronary artery bypass grafting (CABG) despite the long-term risk of competitive flow?

Although multiple series have described diverse ostial repair techniques, uncertainty persists regarding whether certain anatomic patterns may benefit from a more proactive strategy. This has created renewed interest in the concept of a protective bypass, not intended as conventional revascularization but rather as an additional safeguard to ensure reliable myocardial perfusion during the critical postoperative hours. The study under discussion seeks to clarify this issue within a contemporary surgical cohort.

Huang and colleagues from Fuwai Hospital (China) report a large observational retrospective analysis (2019–2023) including 617 patients with ATAAD and coronary involvement. Their objective was to compare surgical outcomes between two approaches: isolated COR versus COR supplemented with a protective CABG, evaluating severe adverse events (operative mortality, need for mechanical circulatory support, or stroke), as well as midterm survival and prognosis.

Patients were categorized according to the severity of ostial involvement using the Neri classification:
• COR group (n=507): isolated coronary ostial reconstruction
• COR + protective CABG group (n=110): saphenous vein graft deployed following ostial repair or closure, generally used in more severe patterns (complex Neri B and Neri C)

The protective CABG group presented markedly more complex coronary anatomy at baseline, with higher rates of coronary malperfusion (p < .001). Despite this, early outcomes favored the protective strategy: procedural myocardial injury was lower (2.73% vs 9.27%), and multivariable analysis showed a significantly reduced adjusted risk of severe adverse events (p = .028). These advantages, however, were accompanied by longer operative, cardiopulmonary bypass, and cross-clamp times.

In contrast, the COR group demonstrated a substantial number of technical failures, frequently requiring intraoperative or early postoperative rescue CABG—36 intraoperative conversions, 5 postoperative CABG procedures, and several rerepairs. These rescue situations were associated with markedly poorer prognosis, underscoring the vulnerability of ostial repair in complex anatomic settings.

Midterm follow-up (2 years) revealed comparable survival between the two strategies (approximately 94%). Nonetheless, graft patency was a limitation: 21.6% of protective CABG patients exhibited graft occlusion during follow-up, predominantly involving saphenous vein conduits. Despite this, graft failure did not translate into differences in survival, suggesting that the principal benefit of the protective bypass is concentrated in the acute perioperative period.

The authors conclude that adding a protective CABG following ostial repair represents a valid and potentially advantageous strategy for anatomically complex lesions. They propose that this approach enhances myocardial safety during the most vulnerable surgical window, offering an additional perfusion source without compromising midterm survival. As such, they advocate considering a more proactive stance when managing severe Neri B and Neri C lesions.

COMMENTARY:

Beyond the numerical results, the study by Huang et al. highlights a crucial issue in surgery for acute type A aortic dissection (ATAAD): the extreme vulnerability of the myocardium when the dissection extends to the coronary ostia. It reflects what we actually face in the operating room and the natural inclination of the surgeon to restore native anatomy whenever possible. However, coronary ostial reconstruction, even in very experienced hands, does not always provide the level of safety required. A repair may be technically correct and still fail to ensure stable myocardial perfusion during the critical postoperative hours because of well-known mechanisms such as tissue fragility, subintimal hematoma, or dynamic compression. These factors carry a non-negligible risk of prolonged ischemia and the need for rescue bypass, scenarios that we know are associated with a sharp increase in mortality.

The protective bypass offers two pragmatic advantages: it provides an additional route for cardioplegia delivery, and it acts as an “insurance policy” against persistent or progressive ostial compromise. In complex Neri B lesions or in Neri C patterns, the data strongly support at least considering this option. The downside is the cost in terms of long-term patency, as late graft occlusion is far from rare. This frequently occurs once edema resolves or the false lumen thromboses, native coronary perfusion is restored, and competitive flow develops. However, the fact that this does not seem to affect survival suggests that the true benefit is concentrated in the acute phase, when the patient’s life is most at risk. Conceptually, the authors argue that surgery for type A dissection should not be approached with the logic of elective coronary revascularization; in this context, we deliberately accept grafts that may not remain patent for many years. By prioritizing short-term solutions, a strategy that would be questionable in elective coronary disease becomes entirely reasonable in a condition as lethal as ATAAD.

This work also underscores the importance of meticulous anatomic assessment and elevates the Neri classification from a purely descriptive tool to a central element in surgical decision-making. At a time when many strategies tend to simplify techniques to save time and improve survival, this study suggests exactly the opposite for the coronary component: we should individualize more, not less. The Neri classification, designed as a practical system more than two decades ago, has not achieved widespread penetration in daily practice, yet it already proposed clear, pattern-based solutions for coronary involvement:

• Neri A: malperfusion should be corrected by sealing the primary entry tear toward the aortic root, provided that root replacement is not required.
• Neri B: an intermediate and more controversial pattern, in which dissection extending into the coronary artery can cause malperfusion or even avulsion. It is a dynamic entity that may change between preoperative imaging and intraoperative inspection. In complex scenarios—such as non-reimplantable ostia or malperfusion not corrected by sealing the entry tear at the root—additional CABG should be considered. This is precisely the setting in which the protective CABG becomes most relevant.
• Neri C: by definition, the entry tear lies at the aortic root, either at the level of the ostial intimal–medial avulsion or along the proximal coronary segment. In addition to persistent malperfusion, this configuration creates a re-entry into the root with a risk of dissection progression. In such cases, ostial closure (with or without aortic root replacement) combined with CABG is recommended.

The authors also force us to reconsider our basic priorities: to what extent should we aim to “do the least,” and when is it reasonable to “do a bit more” to gain safety? The protective CABG is the surgical answer to that question. Although no randomized trials exist (and are unlikely ever to be conducted), this cohort supports the surgeon’s clinical intuition: that moment when, in front of a reconstructed ostium that does not fully inspire confidence, leaving a graft in place may be the most reliable “insurance policy” we can offer the patient.

Finally, although the study does not explore conduit choice in depth, most grafts used were saphenous veins. In a life-threatening emergency where every minute counts, the simplicity and speed of a venous graft are easy to justify. Moreover, if we accept that the graft may serve as a temporary bridge while the native anatomy heals, “spending” the internal mammary artery may not be necessary, allowing us to preserve it for true obstructive coronary disease in the future.

In summary, the protective CABG strategy should not be interpreted as a technical failure, but as a mature tactical decision. Prioritizing immediate myocardial perfusion with a bypass, even at the cost of potential late occlusion, yields favorable short-term results and shields both the patient (and the surgeon) from catastrophic events related to the failure of a complex reconstruction.

REFERENCE:

Huang LC, Shao ZH, Sun YX, Gan LX, Qian XY, Yu CT, Guo HW. Protective Coronary Artery Bypass Grafting Improves Surgical Outcomes in Acute Type A Aortic Dissection With Coronary Ostial Involvement. Ann Thorac Surg. 2025 Sep;120(3):450-460. doi: 10.1016/j.athoracsur.2025.03.025. Epub 2025 Apr 3. PMID: 40187591.