Author + information
- Anno Diegeler, MD, PhD∗ ()
- Department Cardiovascular Surgery, Herz-und Gefässklinik Bad Neustadt, Bad Neustadt a. d. Saale, Germany
- ↵∗Reprint requests and correspondence:
Prof. Anno Diegeler, Herz-und Gefässklinik Bad Neustadt, Department Cardiovascular Surgery, Salzburger Leite 1, 97616 Bad Neustadt a. d. Saale, Germany.
- coronary artery bypass
- coronary vessels
- drug-eluting stents
- follow-up studies
- percutaneous coronary intervention
As early as 1997, Michael Mack’s essay discussed the outlook for the possibility of hybrid revascularization with the emergence of minimally invasive coronary surgery combining the off-pump and minimally invasive direct coronary artery bypass (MIDCAB) techniques with percutaneous coronary intervention (PCI) to a non-left anterior descending (LAD) artery target (1). Since that time, coronary surgery and PCI technology have evolved even more. Off-pump coronary artery bypass surgery and MIDCAB surgery have been established in clinical practice and, with the development of drug-eluting stents, a new era of PCI was born. Despite significantly improved short- and long-term results, the perfect revascularization for each individual patient has not yet been discovered. Surgery is still invasive. There are risks of stroke and bypass occlusions, stent-site restenosis, and acute stent thrombosis, and myocardial infarction has not yet been banished. The data from the SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) trial illustrate the importance of anatomy and morphology in coronary artery disease (2). Conceivably, the good results of both therapeutic approaches could be combined. So, why not use a hybrid therapy more frequently?
What are the Key Pro Arguments?
LAD is the most important coronary artery with the largest coverage area. The mammary artery is the most sustainable revascularization conduit recognized. In randomized trials, PCI, even with the newest generation stents, is, at best, noninferior to coronary artery bypass grafting using arterial conduits, and this is true in all patients, including those with complex coronary morphologies. The successes of coronary bypass revascularization to non-LAD target vessels have not proved superior in any circumstances.
So what is the catch? Why is hybrid coronary revascularization (HCR) not performed more often, and why are the data in published reports so sparse?
The MIDCAB operation is both the backbone and the Achilles’ heel of HCR. The MIDCAB technique is well established and demonstrates very good long-term results (3), but its use is not widespread. Only a few centers have a sufficient volume of MIDCAB patients and procedures; thus, there are only a few specialists who have mastered this operation at the highest level. Many more surgeons are gifted than have been really trained by practice, but only the latter can guarantee excellent results.
PCI is relatively less challenging, but is also not always predictable. Consequently, one might add to the risk of a surgical procedure with its possible “external” complications, such as bleeding, wound healing, arrhythmias, pericardial effusion, thoracic hernia, intercostal pain syndrome, another “internal” coronary risk (i.e., in-stent stenosis, coronary occlusion, and acute myocardial infarction). With stochastic processes, the individual risks of 2 timely, separate procedures do not add up, but collectively contribute to the overall risk.
Consequently, it is not surprising that more than 18 years after Michael Mack predicted its promising prognosis, the spark of HCR has still not been ignited.
But there is no doubt that suitable cases for HCR do exist. Puskas et al. (4) deserve credit for trying to address this issue again, systematically, in this issue of the Journal. In their observational study, they show that HCR of multivessel revascularization is not inferior to multivessel PCI, and that better long-term sustainability could be achieved over time. Does this have to be proved by a randomized trial, or could we put together predictable outcomes, like a puzzle?
The best inclusion criteria for an elective HCR is a complex LAD stenosis (type C morphology) combined with an isolated, short-distance stenosis of a non-LAD segment. The complex type C morphology of the LAD stenosis had a restenosis rate that came close to a treatment failure when using a bare-metal stent (5). Meanwhile, the drug-eluting stents show better outcomes, but the results are far from perfect. This is particularly true in patients with diabetes (6). In addition, patients who are scheduled for HCR should not be at high risk for any surgery, similar to what Puskas et al. (4) describe in their observational trial.
Those ideal conditions for HCR are probably not as frequent. The variability of the anatomy and morphology, and the constitution of the patient, which must be suitable for the MIDCAB procedure, intersects with the expertise of the surgeon. Taken together, this makes it difficult to set up a homogenous HCR treatment group. A further question arises when considering the control group. Should not 2 or even 3 be considered? A “multiple PCI group,” a “complete surgical group,” or (even better) a “surgical off-pump group.” In 2011, Halkos et al. (7) published trial data that compared HCR with off-pump coronary artery bypass surgery and found similar results for major adverse cardiovascular and cerebrovascular events in both groups, apart from repeat revascularization, which was significantly higher in the HCR group (7). Consequently, it can be expected that for the majority of patients with complex 3-vessel CAD, any complete surgical revascularization will lead to better and more sustainable results than PCI and HCR.
On the other side of the scale, it is expected that PCI is noninferior to surgical revascularization if the LAD lesion is not too complex and a SYNTAX score of 32 has not been reached.
The role of HCR is more on the individual patient’s side; thus, the selection of an ideal candidate is part of the decision-making between the cardiologist and the cardiac surgeon within the heart team. The necessary evidence for making this decision lies more in the institutional experience and results than in a randomized trial.
The patient's expectation should have secondary importance, with the long-term results having priority. It is always appealing to look for less-invasive treatment strategies. In cardiac diseases, we increasingly tend to offer shortsighted treatment, and only a few people ask what will come further down the road. In cancer treatment, no patient would ask about the length of hospital stay, but rather, “Will I still be alive in 5 years.”
Considering this “the best of both worlds” may be an appealing and successful offer for a number of individual patients. But for the majority, complete surgical revascularization might be the treatment of choice. The majority of patients could be randomized and compared to other majorities. It is hard to do the same with highly selected subjects.
And one more thing: if we always favor a randomized trial, we should keep in mind that noninferior does not mean better.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Diegler has reported that he has no relationships relevant to the contents of this paper to disclose. Friedrich-Wilhelm Mohr, MD, PhD, served as Guest Editor for this paper.
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