Total hip and total knee replacement procedures were associated with an increased risk of heart attack in the first 2 weeks postoperatively, according to a report published in Archives of Internal Medicine.
“This study demonstrated an increased risk of [heart attack] during the first 2 weeks after THR [total hip replacement] (25-fold) and TKR [total knee replacement] (31-fold) surgery compared with matched controls,” study author Arief Lalmohamed, PharmD, stated in a news release. “The risk of [heart attack] sharply decreased after this period, although it remained significantly elevated in the first 6 weeks for THR patients.”
“The association was strongest in patients 80 years or older, whereas we could not detect a significantly increased risk in patients younger than 60 years,” Lalmohamed added.
The authors performed a retrospective, nationwide cohort study within Danish national registries involving 95,227 patients who underwent either THR or TKR from 1998 to 2007. Each patient was matched to three controls who had not undergone THR or TKR. Follow-up primarily examined heart attack.
According to the study abstract, the authors found the risk of heart attack to be substantially increased in THR patients when compared with controls. This risk remained elevated for 2 weeks to 6 weeks postoperatively, and then returned to baseline levels.
TKR patients also experienced an increased risk of heart attack for the first 2 weeks postoperatively, but these patients did not differ from controls after 2 weeks. Absolute 6-week risk of heart attack for THR patients was 0.51%, and 0.21% in TKR patients.
“Furthermore, a previous [heart attack] in the 6 months before surgery increased the risk of new [heart attack] during the first 6 weeks after THR and TKR (4-fold increase) surgery but did not modify the relationship between THR or TKR and [heart attack],” the authors wrote.
Lalmohamed A, Vestergaard P, Klop C, et al. Timing of acute myocardial infarction in patients undergoing total hip or knee replacement: A nationwide cohort study. Arch Intern Med. 2012. doi: 10.1001/archinternmed.2012.2713