Last Updated:  03/08/2009

The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author.  Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.

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CORONARY ARTERY DISEASE: CABG vs. STENTS?

The debate over the optimal treatment of coronary artery diseases continues, even among top heart disease experts.  Much of the clinical research thus far has suggested that coronary artery stents work about as well as the far more invasive coronary artery bypass grafting (CABG) surgery does, at least in the short term, but that the benefits of CABG surgery tend to last longer than coronary artery stents.  Of course, the risks associated with CABG surgery, especially in the early period after surgery, tend to be higher than for stent placement (although patients undergoing CABG surgery also tend to have more advanced coronary artery disease than patients who are typically selected for less invasive coronary artery stent placement procedures).

A new prospective, randomized clinical research trial, just published in the New England Journal of Medicine, further clarifies important differences in outcomes among patients undergoing coronary artery stent placement versus CABG surgery.  In this impressive interventional study, 1,800 patients with coronary artery disease involving either all 3 major coronary arteries or the dominant “left main” coronary artery were randomized to undergo either CABG surgery or coronary artery stent placement (also known as percutaneous coronary intervention, or PCI).  Historically, patients with these patterns of advanced coronary artery disease have been advised to undergo CABG surgery instead of PCI, due to the improved durability of CABG, over time, when compared to PCI.  However, given the minimally invasive nature of coronary artery stent placement, when compared to CABG surgery, both cardiologists and patients have a strong interest in learning whether or not more advanced cases of coronary artery disease can be effectively treat with PCI instead of CABG surgery.

Following CABG or PCI, the 1,800 patient volunteers were observed for an average period of one year, and the incidence of death (from any cause), heart attack, stroke, or the need for additional coronary artery disease interventions, was tracked in both patient groups.

The results of this study largely confirmed earlier clinical studies that have favored CABG surgery over PCI in patients with diseased left main coronary arteries, and in patients with 3-vessel coronary artery disease.  The incidence of major acute coronary artery events was significantly higher in the PCI group when compared to the CABG surgery group (18 percent in the PCI group versus 12 percent in the CABG surgery group).   Much of this observed difference in recurrent coronary artery events between the two patient groups appeared to derive from the two-fold increase in the need for repeat coronary artery interventions in the PCI patient group when compared to the CABG surgery patients.  Nearly 14 percent of the PCI patients required a repeat coronary artery intervention within 12 months of their initial PCI procedure, while only 6 percent of the CABG surgery patients required another coronary artery intervention within a year of their initial surgery.  At the same time, it is important to note that, at 12 months following initial coronary artery intervention, the death rate and the heart attack (myocardial infarction) rate was essentially equivalent between the two patient groups, and the stroke rate was actually higher in the CABG surgery group (2 percent in the CABG surgery group versus 0.6 percent in the PCI group). 

The authors of this study concluded that, after one year of follow-up, CABG surgery was superior to coronary artery stent placement (PCI), as the patients who underwent PCI were twice as likely to require subsequent coronary artery interventions when compared to the patients who had undergone CABG surgery.  However, in my view, the results of this study, as published are somewhat more equivocal, especially from a patient’s perspective.  Although the duration of follow-up in this study (one year) was very brief, this study revealed that the overall death rate was essentially equivalent with either intervention, and many patients in the PCI group were spared the need for major open-heart surgery (and its attendant higher risk of stroke).  Ultimately, it will require longer follow-up of this cohort of patients, in my view, to prove the claimed superiority of CABG surgery over PCI for 3-vessel or left main coronary artery disease.  Based upon previous research studies, one would anticipate that, over a period of 10 to 15 years, the patients who underwent CABG surgery in this study are likely to experience fewer adverse cardiovascular events than the patients who underwent PCI.  As other recent clinical studies have shown, though, the differences in important clinical outcomes during the first few years following either CABG surgery or PCI may be far less than what older studies have suggested, and this narrowing of differences in early outcomes may reflect recent advances in PCI.  For now, in my view, the debate regarding the inherent superiority of CABG over PCI for certain groups of patients with coronary artery disease has not yet been fully resolved by this important new study, and only long-term follow-up of this study’s patient volunteers is likely to definitively decide this ongoing debate.

 

SWIMMING LESSONS & DROWNING RISK IN CHILDREN

My wife, it can be revealed, never learned to swim, despite spending most of her life living in beach communities.  As a form of parental compensation for my wife’s lack of comfort in an aquatic environment, our two young children have been charged with learning to swim from a very early age.  Of course, this makes perfect sense to me as well, given that we continue to live near the beach.  However, due to the not very infrequent tragic stories of young children drowning in family pools, I have sometimes worried that increasing our young children’s comfort levels in the water could expose them to an increased risk of a pool-related accidents, due to overconfidence on their part.  I was, therefore, quite relieved to find a newly published research study on this very topic, which appears in the current volume of the Archives of Pediatric and Adolescent Medicine. 

In this retrospective case-control study, the authors reviewed cases of drowning deaths occurring in children and adolescents between the ages of 1 and 19 years in the states of Maryland, North Carolina, Florida, California, Texas, and New York.  The researchers then interviewed a sample of 88 families of children and teens, from these same states, who had died in drowning accidents.  A control group of 213 families who had not experienced the tragic loss of a child was also interviewed.  The results and conclusions of this innovative clinical study were rather striking (and personally reassuring to me).

Of the 61 families who lost a child between the ages of 1 and 4 years to drowning, only 3 percent had enrolled their lost child in swimming lessons, while 26 percent of the control group families with children in this same age range had enrolled their toddlers in formal swimming lessons.  Among the 27 families that had lost children between the ages of 5 and 19 years to drowning accidents, 27 percent had enrolled their deceased children in formal swimming lessons, compared with 53 percent of the same-aged children in the 79 control group families.  (While these results suggest that formal swimming instruction in children aged 5 years or older decreases the risk of accidental drowning, the results in this age group were not statistically significant, unlike the results observed for the younger children.)  At the same time, when the researchers looked at unstructured or otherwise informal swimming instruction as a risk factor for accidental drowning, they found absolutely no association between informal instruction and drowning rates in children and adolescents.

The results of this retrospective case-control study identified a whopping 88 percent reduction in the risk of accidental drowning among 1 to 4 year-old children who had undergone formal swimming instruction, when compared to same-age toddlers who had either never undergone formal instruction or who had undergone only informal, unstructured swimming instruction.  While the retrospective case-control methodology used for this study is not as powerful as would be observed in a prospective clinical research trial, this study’s findings do reassure me that there is most likely some significant benefit associated with formal swimming lessons in younger children.  Selection biases, as well as other potential sources of bias, are difficult to eliminate in these types of clinical studies, and so the absolute benefit of swimming lessons is likely to be less than the 88 percent level reported by this retrospective study.  However, when one is considering even potentially modest reductions in the risk of losing one’s child to accidental drowning, there is no such thing as a trivial level of risk reduction, in my view.  So, our young children will definitely be continuing with their swimming lessons at our friendly neighborhood YMCA.

Disclaimer:  As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity

 

Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and the Physician-in-Chief for Surgical Oncology at the Kaiser Permanente healthcare system in Orange County, California

  

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