Long-term Stroke Rate Higher With CABG vs Stenting

July 18, 2018

Five-year stroke rates were lower in patients with multivessel or left main coronary artery disease who underwent percutaneous coronary intervention (PCI) than in those who had coronary artery bypass grafting (CABG), new research shows.

The patient-data pooled analysis included 11,518 patients from 11 randomized trials. It showed significantly lower 30-day risk for stroke in the PCI group, with similar rates of stroke in the two groups between 31 days and 5 years, resulting in the 5-year rate remaining lower in the stented patients.

Results also showed that strokes occurring within 30 days after the procedures were strongly associated with increased long-term mortality, with a rate approaching 50% at 5 years.

The findings were published online July 16 in the Journal of the American College of Cardiology.

Long-term Data

"We knew from the previous data that CABG was associated with a higher stroke risk than stenting in the short term but we weren't sure if that would be the case in the longer term, especially as stenting has a higher rate of repeat revascularizations," lead author Stuart J. Head, MD, Erasmus Medical Center, Rotterdam, the Netherlands, told Medscape Medical News.

For the study, the investigators performed a collaborative individual-patient-data pooled analysis of 11 randomized clinical trials comparing CABG with PCI using stents; the trials were ERACI II, ARTS, MASS II, SoS, SYNTAX, PRECOMBAT, FREEDOM, VA CARDS, BEST, NOBLE, and EXCEL.

The 30-day and 5-year stroke rates were compared between CABG and PCI by using a random-effects Cox proportional hazards model, stratified by trial.

The 11,518 patients had a mean follow-up of 3.8 years, during which a total of 293 strokes occurred.

Results showed that at 30 days, the stroke rate was 0.4% after PCI and 1.1% after CABG (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.20 - 0.53; P < .001).

At 5-year follow-up, stroke remained significantly lower after PCI than after CABG (2.6% vs 3.2%; HR, 0.77; 95% CI, 0.61 - 0.97; P = .027).

The increase in stroke rates with CABG was particularly pronounced in patients with diabetes, in whom the risk for stroke was nearly doubled after CABG (4.9%) compared with PCI (2.6%), whereas the stroke rates were almost identical between the two procedures in patients without diabetes.

Higher Risk in Select Populations

The composite of all-cause mortality or stroke at 30 days was 1.6% after PCI vs 2.4% after CABG (P = .003). Between 31 days and 5 years, this composite was higher after PCI compared with CABG (11.6% vs 9.3%; P < .001).

However, by 5 years the difference did not quite reach statistical significance (13.0% vs 11.4%; P = .069). Although there were no significant interactions, the benefit of CABG over PCI was generally seen in patients with diabetes and higher SYNTAX scores

"Our data confirm the lower risk of stroke with stenting at 30 days and shows that there doesn't appear to be a late catch-up in stroke rates in the stenting group as some had expected," said Head, a cardiac surgeon.

However, stroke rates go in the opposite direction of the mortality results. In a previous paper from the same meta-analysis published  in March in the Lancet, the researchers reported significant differences in 5-year all-cause mortality in favor of CABG over PCI.

The greater risk for stroke and the lower risk for death with CABG vs stenting both appear to be confined to patients with advanced complicated mutlivessel disease and those with diabetes.

In the current paper, the researchers report that the composite of all-cause mortality or stroke was lower after PCI compared with CABG at 30 days but was higher after PCI at 5 years.

While the difference at 5 years was not significant in the whole population, it was more pronounced in patients with diabetes, multivessel disease, and high SYNTAX scores.

Head noted that when a patient has multivessel disease and there is a choice between stenting and surgery, each case should be reviewed by an interventional cardiologist and a cardiac surgeon together to weigh stroke and mortality risks.     

"This latest data will help them reach a conclusion on which procedure is best for which patient. Generally, nondiabetics with relatively simple coronary disease will have good results with PCI. Patients with more complicated disease and diabetics may do better with CABG," he said.

Important New Findings

Coauthor of the accompanying editorial, Amar Krishnaswamy, MD, an interventional cardiologist from the Cleveland Clinic, Ohio, told Medscape Medical News the meta-analysis confirms observations from previous trials that stroke rate is lower with stenting than with bypass surgery. 

"[The fact] that the long-term results also show lower stroke rates with stenting is an important new finding. While clinicians often discuss the mortality benefit of CABG, this paper shows that we must also think about stroke risk."

He noted the overall results on stroke and mortality suggest that different recommendations are appropriate for different patients.

"If coronary anatomy is amenable to both procedures, a thorough review of risks and benefits for each individual patient is needed. The current results would lead me to recommend stenting for most patients in whom it is anatomically feasible and who are nondiabetics.  

"For diabetics and those with extensive multivessel disease, surgery may be preferable, but then surgeons need to think carefully about strategies to minimize stroke risk."

The current study was performed without funding. Head and Krishnaswamy have disclosed no relevant financial relationships.

J Am Coll Cardiol. 2018;72:386-398. Published online July 16, 2018. Abstract, Editorial

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