CHICAGO – Many traditional and novel biochemical cardiac risk markers show dramatic and stable improvements following sleeve gastrectomy, a prospective, observational study shows.
C-reactive protein (CRP) levels were elevated in 78% of patients preoperatively, but they fell early in the preoperative course at 3 months (median 6.6 mg/L vs. 4.5 mg/L; P less than .0001) and continued to decline throughout the 12-month follow-up (median 5.8 mg/L vs. 2.4 mg/L; P less than .0001).
“This gradual improvement and normalization of this inflammatory marker may reflect the slower resolution of the chronic inflammatory burden that obesity brings along with it,” Ms. Tara Mokhtari said at the American College of Surgeons Clinical Congress.
Though prior studies have shown that gastric bypass and adjustable gastric banding improved biochemical cardiac risk factors (BCRFs), this is the first prospective study to detail such improvements following sleeve gastrectomy.
The study evaluated 10 BCRFs (total cholesterol (TC), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides (TG), TC/HDL ratio, hemoglobin A1c, TG/HDL ratio, homocysteine, lipoprotein A, and CRP) in 334 morbidly obese patients undergoing laparoscopic sleeve gastrectomy during 2006-2015. Their mean age was 45 years, 76.4% were women, 55% were hypertensive, 29.4% had diabetes, 9.6% had known coronary artery disease, and 26.4% were on a lipid-lowering medication.
Many patients had abnormal cardiac risk factors prior to surgery, the most striking being the 78% of patients with elevated CRP levels (at least 3 mg/L), according to Ms. Mokhtari of Stanford (Calif.) University.
One-third also had abnormal HDL levels, total cholesterol, and triglyceride/HDL ratio and 20% had LDL levels above the 130 mg/dL threshold. Statin use was discontinued in all patients following surgery, per hospital protocol.
After sleeve gastrectomy, body mass index declined from 43.5 preoperatively to 36.6 at 3 months, 34.3 at 6 months, and 33.1 at 12 months, according to the study authors, led by Dr. John M. Morton, also of Stanford.
Similar to the early changes observed in CRP, there were significant changes from baseline at 3 months in triglycerides (116.5 mg/dL vs. 98.5 mg/dL; P less than .0001) and HbA1c (5.8% vs. 5.5%; P less than .0001).
Six months after sleeve gastrectomy, significant improvements were seen in these same risk factors as well as HDL cholesterol (47 mg/dL vs. 51 mg/dL; P less than .0001), TG/HDL ratio, a surrogate marker for metabolic syndrome (2.5 vs. 1.9; P less than .0001), and lipoprotein A (8.9 mg/dL vs. 5.4 mg/dL; P = .016), Ms. Mokhtari said.
By 12 months, all cardiac risk factors except LDL cholesterol (median preop 101.5 mg/dL vs. 102.5 mg/dL; P = .062) were significantly improved. Notably, HDL increased to a median of 54 mg/dL, triglycerides continued to decline to 93 mg/dL, and HgA1c held steady at 5.5%.
“Triglycerides fell dramatically and remained stable, which in combination with the increase in HDL, reflects a much healthier overall lipid profile for our post-sleeve patients,” Ms. Mokhtari said. “It’s important to recall that all of these improvements were seen without the use of a statin drug.”
Improvement in these cardiac biomarkers may further represent improvements in other obesity-related diseases, as evidenced by improvements in the markers for type II diabetes and metabolic syndrome, she said.
“Such risk factors are useful in determining baseline risk for our sleeve patients and also can be followed very easily in the postoperative period,” Ms. Mokhtari added.
Discussant Dr. Aurora D. Pryor of State University of New York at Stony Brook, congratulated the authors on their research and asked how sleeve gastrectomy stacks up to gastric bypass or banding as a procedure for metabolic disease and whether the biomarker improvements will translate into improved mortality.
There are several published reports on cardiac risk factors and gastric banding and Roux-en-Y gastric bypass, but many do not include the newer biomarkers of lipoprotein A, homocysteine, or CRP, Ms. Mokhtari observed. A 2006 study by the Stanford investigators, however, suggests that “overall, Roux-en-Y allowed for a more significant improvement in these risk factors compared to sleeve,” she said.
Ms. Mokhtari went on to say that the SOS study reported a decrease in cardiovascular events after Roux-en-Y bypass, but that no such solid evidence exists for sleeve gastrectomy. However, studies have shown comparable improvements in Framingham risk scores at 1 year between sleeve and Roux-en-Y.