Sales of medical devices at Abbott Laboratories grew by 9 percent last year, making med-tech the largest and fastest-growing division at the $30 billion Chicago-based health care supplier.

But the device brands that Abbott obtained in its acquisition of Little Canada-based St. Jude Medical two years ago didn't necessarily drive that growth.

Whether they will remains to be determined, but Abbott Chief Executive Miles White told investors in a quarterly earnings call Wednesday that steps are being taken to bolster growth in areas like neuromodulation devices to treat chronic pain.

While Abbott's profit met expectations in the fourth quarter, the company reported top-line growth that narrowly missed Wall Street's 3 percent projection. Investors sent Abbott shares down 2.2 percent.

In the call with analysts, White praised the rapid growth and huge commercial potential of Abbott products like the FreeStyle Libre continuous glucose monitor and the minimally invasive MitraClip for the heart's mitral valve. But he added that sales of the company's neuromodulation devices ­— acquired in its St. Jude deal — have not improved as well as he had hoped.

He acknowledged that, in previous earnings calls, he had overestimated how quickly neuromodulation could correct its direction. "It's taken a little longer than I would have guessed. But that's going to get sequentially better," White said.

Neuromodulation devices are essentially specialized pacemakers designed to treat pain instead of heart problems. Abbott's devices, including the Proclaim DRG Neurostimulation system and the Prodigy MRI spinal cord stimulation system, have several unique proprietary features. And like all neurostimulators for pain, they represent a potential alternative to opioids in an era of great national anxiety about opioid overuse.

Sales of neuromodulation devices grew by less than 1 percent year-over-year in the fourth quarter to $218 million, representing the third consecutive quarter of sluggish growth. After growing 43 percent during the full year of 2017, neuromodulation sales grew by 6.5 percent in 2018.

White said the most significant immediate step to pick up the pace of neuromodulation sales growth is the expansion and training the U.S. sales force. He said Abbott has doubled its research-and-development investment in the area as well.

"We don't think we've sort of fully gotten the benefit of the two main products we have now," White said. "So I'd say, it's got our attention."

Another longtime St. Jude product division was heart-rhythm devices, including pacemakers and implantable defibrillators. Abbott's sales of heart-rhythm devices fell by 1.5 percent in 2018, but still accounted for $2.1 billion in revenue.

In 2017, Abbott's first year of running the business, sales in the same division declined 8 percent.

"As you know, when we acquired that business, it was declining at a fairly heavy clip. We've been able to stabilize it," Scott Leinenweber, investor relations vice president, told analysts Wednesday, noting that its performance is generally in line with the overall market.

Sales were falling in the business because St. Jude had fallen behind its rivals in gaining regulatory approval to market heart devices that are compatible with MRI scanners.

The cybersecurity of St. Jude's heart devices also came under assault by a short-selling financial firm, causing Abbott to eventually issue software updates for thousands of heart devices with wireless communications capabilities. Abbott also lacks a small leadless pacemaker to compete with Medtronic's Micra device.

On Wednesday, White praised the 20 percent growth in the electrophysiology division, which hit $1.7 billion in revenue in 2018 led by sales of the Advisor HD heart-mapping catheter and a new TactiCath sensor-enabled ablation catheter — both of which were St. Jude franchises.

Companywide, fourth-quarter adjusted earnings of 81 cents per share met Wall Street expectations and represented 9 percent growth over the same quarter last year. But Abbott's top line revenue grew by 2 percent to $7.77 billion for the just-ended quarter, shy of the 3 percent growth that had been anticipated by Wall Street analysts. Each of the company's four major product groups showed organic sales growth in the fourth quarter.

For the full year, adjusted earnings per share rose 15.2 percent, to $2.88. Revenue was up 11.6 percent, to $30.58 billion.

Abbott paid down $8 billion of its corporate debt in 2018, including debt related to the $25 billion St. Jude acquisition, with the goal of attaining greater financial flexibility. Yet when asked, White said the company isn't actively planning major mergers in the coming year, because it doesn't see major holes in its catalog and because deal prices are high in the current financial climate.

"You earn your highest return on organic growth," White said, contrasting growth from ongoing activities with growth from mergers-and-acquisitions, or "M&A." "There's times to be in M&A markets, and there are times not to be. And you know when multiples are really high — bad time to buy."

For 2019, Abbott said that it expects to see 6.5 percent to 7.5 percent organic-sales growth and adjusted diluted earnings of $3.15 to $3.25 for the full year. For the first quarter of 2019, Abbott is guiding to adjusted EPS of 60 to 62 cents.

Abbott shares closed Wednesday at $69.91, down $1.58 on the day, or 2.2 percent.

Joe Carlson • 612-673-4779