Study: Patients taking aspirin can safely undergo PCNL

Gainesville, FL-Percutaneous nephrolithotomy (PCNL) in the presence of aspirin appears both effective and safe. In a retrospective review of almost 300 PCNL cases, postoperative hemorrhage was uncommon in patients who continued aspirin preoperatively, said Brandon Otto, MD, at the AUA annual meeting in San Diego.

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Concern over postoperative hemorrhage, therefore, “should not dissuade urologists from offering PCNL with perioperative aspirin use to this patient population,” he said.

More than 50 million adults worldwide take aspirin daily or every other day, for either primary or secondary prevention of cardiovascular events, said Dr. Otto, an endourology/minimally invasive surgery fellow at the University of Florida, Gainesville. Long-term aspirin is recommended by multiple guidelines for secondary prevention of cardiovascular events, having been shown to decrease the risk of a future vascular event by 22%.

Perioperative transfusion rates associated with PCNL have been reported at 1% to 15%, and the angioembolization rate for delayed bleeding is about 1%.

“As a result, urologists typically hold antiplatelet agents such as aspirin for 5 to 10 days prior to their procedure,” he said. “However, there is mounting evidence that aspirin discontinuation is associated with increased thrombotic events.” These include cardiac complications in susceptible patients and recurrent stroke.

“The timing of these events is often when we’re performing our surgery or in the early postoperative period. This puts us in a bit of a dilemma as the surgeon is trying to balance the bleeding risk of our procedure with the thrombotic risk that our patients may face,” said Dr. Otto, who worked on the study with Vincent G. Bird, MD, and colleagues.

Given this increasing concern about thrombotic events, aspirin has been continued in all patients undergoing PCNL at the University of Florida since 2012. Dr. Otto reviewed his institution’s experience following institution of this policy.

His group retrospectively reviewed 285 consecutive PCNL cases performed between 2012 and 2015. They identified patients who were maintained on aspirin, and compared perioperative outcomes and complication rates to those among patients who were not taking aspirin.

PCNL access is obtained with interventional radiology in the operating room.

“We typically dilate to a 24F or 30F tract,” he said. “These are not tubeless procedures; everyone gets some sort of an internal stent and has a 16F council tip catheter that serves as a nephrostomy tube.” Most patients undergo computed tomography on postoperative day 1, with removal of the Council tip catheter if the patient is stone-free.

Seventy-seven patients (27%) were maintained on aspirin. Indications for aspirin were primary prevention in 58.4% and secondary prevention in 41.6%. The vast majority of aspirin users (85.7%) were maintained on 81 mg/day. Thirty-one percent of aspirin users had a history of coronary artery disease, 13% had a coronary stent placed, 7.8% had a cerebrovascular accident, 14.3% had peripheral vascular disease, 9.1% had atrial fibrillation, 70.1% had hypertension, 44.2% had hyperlipidemia, and 28.6% had diabetes mellitus.

The aspirin users were significantly older than those not taking aspirin (median age, 66 vs. 51 years; p<.001). Significantly more aspirin users had a history of smoking compared with non-users (55.8% vs. 31.7%; p<.001) and aspirin users had a higher mean American Society of Anesthesiologist score (2.9 vs. 2.5; p<.001).

Next: No difference in blood loss between groups

No difference in blood loss between groups

The aspirin group underwent more left-side procedures (p=.03) and had a significantly shorter operating time than the non-aspirin group (158 vs. 184 min; p=.002). There were no significant differences between groups in estimated blood loss, number of tracts, or tract dilation method.

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Postoperatively, there were no differences in mean residual stone size between the aspirin and non-aspirin groups, with most patients in each group having residual stone fragments ≤2 mm. There were also no differences in the change of hemoglobin, hematocrit, or serum creatinine levels between the groups.

At 30 days, there were no significant differences in the number of readmissions between the aspirin and non-aspirin groups (12.4% in each group) or the percentage of patients with complications (31.6% vs. 26.7%; p=.401). The rate of major complications, defined as ≥Clavien III, was also not significantly different between the aspirin and non-aspirin groups (8.9% vs. 5.7%; p=.366).

Additionally, there were no significant differences in the percentage of patients with bleeding complications (3.8% vs. 3.3%; p=.853), the percentage requiring transfusion (1.3% vs. 1.0%; p=1.0), and the percentage with postoperative thrombotic events (1.3% vs. 0%; p=.273) between the aspirin and non-aspirin groups.

Follow-up at 90 days showed bleeding complications in 6.4% of the aspirin group.

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