Dialysis raises short-term death risk in kidney patients undergoing TAVI

Kidney dialysis is an independent predictor of mortality in end-stage renal disease (ESRD) patients undergoing transcatheter aortic valve implantation (TAVI), according to a seven-year trial of 2,000 men and women in Karlsruhe, Germany.

The study, launched in 2008 and published a decade later in the American Journal of Cardiology, focused on a subset of kidney patients that are often ignored in clinical trials—those with ESRD. First author Gerhard Schymik, MD, and colleagues at Municipal Hospital Karlsruhe wrote that while anywhere between 10 and 50 percent of aortic stenosis (AS) patients will develop chronic kidney disease (CKD), just 2 to 4 percent of those with AS will experience ESRD.

Kidney complications have been linked to poor TAVI prognosis before, and numerous studies have explored the risks of undergoing the procedure as a CKD patient. But, the authors said, few researchers have focused on optimizing treatment for ESRD patients considering TAVI.

“While multicenter registries have advantages in their representativeness of clinical practice, their interpretation is hampered by site-specific approaches to TAVI including very experienced, but also quite inexperienced sites, resulting in a potential bias for the interpretation of data,” Schymik et al. wrote. “We aimed to explore differences in procedural and longer-term outcomes in dialysis patients compared to patients not undergoing dialysis under the assumption that single centers are less prone to disease-unrelated bias.”

Schymik and colleagues’ 2,000 patients were enrolled when they were first diagnosed with severe AS and deemed eligible for TAVI. At the study’s baseline, the patients were divided into a dialysis group (56 patients, or 2.8 percent of the pool) and a non-dialysis group (1,944 patients).

Comparing patient characteristics after TAVI, the researchers found patients on dialysis, who tended to be younger and male, saw significantly higher rates of mortality across the board. Dialysis patients saw a nearly six-fold increased risk of 72-hour periprocedural mortality compared to non-dialysis patients.

At 30 days, dialysis patients still saw a nearly five-fold increased risk of all-cause mortality when compared to non-dialysis patients, as well as a 3.7-fold increased risk of cardiovascular death, a 6.3-fold increased risk of non-cardiovascular death, a 9.4-fold increased risk of myocardial infarction and a 2.5-fold increased risk of bleeding events.

Schymik et al. also found dialysis was linked to poorer survival at one and three years, and a handful of confounding factors could compound that risk.

“While in the multivariable regression analysis reduced ejection fraction, peripheral arterial disease, pulmonary hypertension (PH), frailty and dialysis were associated with one-year mortality, only PH remained significant in an analysis restricted to the dialysis patients,” the authors explained.

“Dialysis is an independent predictor of procedural and long-term mortality in patients undergoing TAVI,” they wrote. “While long-term mortality appears to be largely determined by kidney disease or dialysis itself, short-term mortality still calls for pre-procedural optimization.”