From the Journals

Can better operations improve CABG in women?


Key clinical point: Survival rates after CABG are worse for women than for men.

Major finding: In both men and women, complete revascularization and use of bilateral-ITA grafting achieve better long-term survival than incomplete revascularization and single-ITA grafting.

Data source: Analysis of 57,943 adults who had primary isolated CABG from 1972 to 2011 at Cleveland Clinic.

Disclosure: Coauthor Ellen Mayer Sabik, MD, is a principal investigator for Abbott Laboratories and is on the scientific advisory board of Medtronic. Dr. Attia and all other coauthors reported having no relevant financial disclosures.

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Consider postoperative risk factors

As with other long-term analyses, the answer in this study “is in the shadows as opposed to the spotlight,” George L. Hicks Jr., MD, said in his invited commentary (J Thorac Cardiovasc Surg. 2017;153[3]:580-1).

Dr. Hicks of the University of Rochester (N.Y.) noted key limitations of the study: use of all-cause mortality, substandard use of bilateral– or single–internal thoracic artery grafting, little data about postdischarge cholesterol levels, diabetes incidence, or blood pressure, among others. However, “the authors raise the banner for the continued need for increased use of arterial revascularization with the eventual hope that the Arterial Revascularization Trial will reinforce the survival benefits manifested by that strategy,” he said.

Dr. George L. Hicks Jr.

Dr. George L. Hicks Jr.

Dr. Hicks invoked the besseller, “Men Are From Mars and Women From Venus.” “If men are truly from Mars and different from the women of Venus, it behooves all practitioners to aggressively monitor and treat women after menopause for the potential – if not inevitable – onset of cardiovascular problems, hypertension, hyperlipidemia, diabetes, and stroke,” Dr. Hicks said.

Reducing risks and not changing the type of operation will even out the differences in postoperative survival between genders, he indicated. “Furthermore, the extension of similar therapies – for example, [bilateral–internal thoracic artery] or all-arterial grafting and improved long-term risk modification in both men and women – may improve the inequality but not eliminate the differences until we know that both men and women come from the same planet,” he said.

Dr. Hicks reported having no relevant financial relationships to disclose.



Worse outcomes after cardiovascular arterial bypass grafting (CABG) in women have been attributed to a number of clinical and nonclinical factors: older age, delayed diagnosis and treatment, more comorbidities, smaller body size, underuse of arterial grafts, and referral bias. However, a team of Cleveland Clinic researchers reported that women were less likely than men to have bilateral–internal thoracic artery (ITA) grafting and complete revascularization, both of which are linked to better long-term survival.

Survival was lowest in women who were not completely revascularized and had no ITA grafting, while survival was highest in men who were completely revascularized and had bilateral grafting, Dr. Attia and coauthors said.

The researchers’ goal was to use extensive risk adjustment to evaluate how differences in revascularization strategies influenced survival of men and women after CABG. They analyzed 57,943 primary, isolated CABG procedures performed at Cleveland Clinic from 1972 to 2011, including 11,009 procedures in women.

The researchers identified differences between sexes in three key areas: revascularization strategies, in-hospital outcomes, and time-related survival.

With regard to revascularization strategies, while men were significantly more likely to have incomplete revascularization than were women, women received significantly fewer arterial grafts (8.4% vs. 9.3% for men). This included fewer bilateral-ITA grafts and radial artery grafts, less use of total arterial revascularization, and greater use of saphenous vein grafts (SVGs) to the left anterior descending artery. Women were also significantly more likely to receive only SVGs for revascularization (32% vs. 30% for men; P less than .0001). Most operations for both women and men were done with cardiopulmonary bypass, but significantly more women had off-pump procedures (5.4% vs. 2.9%).

In the hospital after operations, women were significantly more prone to postoperative deep sternal–wound infections and septicemias, as well as strokes and renal failure, including dialysis-dependent renal failure. Women also had higher rates of new-onset atrial fibrillation (15% vs. 13% in men), and higher rates of mechanical ventilation for more than 24 hours (13% vs. 9.2%). Women spent more time in the ICU and hospital overall, and their in-hospital death rate was more than double that of men (2.7% vs. 1.1%).

Women also had shorter long-term survival, “and this has persisted since the beginning of CABG at Cleveland Clinic,” Dr. Attia and coauthors said. What’s more, the survival gap between women in the study and women in the general population post CABG was wider than that in men. “After we adjusted for patient and revascularization strategy differences, female sex remained an independent risk factor for death overall and both early and late after CABG.”

Incomplete revascularization had greater consequences for women than for men. At 10 years, 58% of women with incomplete revascularization survived, vs. 70% of men. At 20 years, the rates were 25% for women and 35% for men. “Use of ITA grafts was associated with better survival than use of SVGs alone and was best when bilateral-ITA grafting was performed,” Dr. Attia and coauthors said. However, the study determined that bilateral grafting seems less effective in women long-term. “Hence, a patient’s sex deserves special consideration in operative planning.”

Many questions about CABG in women remain: Identifying which female patients would benefit from more meticulous conduit harvesting, from better coronary artery selection, and from bilateral-ITA grafting and which are less susceptible to sternal would infections could increase appropriate use of bilateral-ITA grafting, the researchers noted. “The difference in effectiveness of bilateral-ITA grafting needs to be considered in women at elevated risk for bilateral-ITA harvesting complications.”

Coauthor Ellen Mayer Sabik, MD, is a principal investigator for Abbott Laboratories and is on the scientific advisory board of Medtronic. Dr. Attia and all other coauthors reported having no relevant financial relationships to disclose.

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